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In this paper, a concept for an anthropomorphic replacement hand cast with silicone with an integrated sensory feedback system is presented. In order to construct the personalized replacement hand, a 3D scan of a healthy hand was used to create a 3D-printed mold using computer-aided design (CAD). To allow for movement of the index and middle fingers, a motorized orthosis was used. Information about the applied force for grasping and the degree of flexion of the fingers is registered using two pressure sensors and one bending sensor in each movable finger. To integrate the sensors and additional cavities for increased flexibility, the fingers were cast in three parts, separately from the rest of the hand. A silicone adhesive (Silpuran 4200) was examined to combine the individual parts afterwards. For this, tests with different geometries were carried out. Furthermore, different test series for the secure integration of the sensors were performed, including measurements of the registered information of the sensors. Based on these findings, skin-toned individual fingers and a replacement hand with integrated sensors were created. Using Silpuran 4200, it was possible to integrate the needed cavities and to place the sensors securely into the hand while retaining full flexion using a motorized orthosis. The measurements during different loadings and while grasping various objects proved that it is possible to realize such a sensory feedback system in a replacement hand. As a result, it can be stated that the cost-effective realization of a personalized, anthropomorphic replacement hand with an integrated sensory feedback system is possible using 3D scanning and 3D printing. By integrating smaller sensors, the risk of damaging the sensors through movement could be decreased.
Linear acceleration is a key performance determinant and major training component of many sports. Although extensive research about lower limb kinetics and kinematics is available, consistent definitions of distinctive key body positions, the underlying mechanisms and their related movement strategies are lacking. The aim of this ‘Method and Theoretical Perspective’ article is to introduce a conceptual framework which classifies the sagittal plane ‘shin roll’ motion during accelerated sprinting. By emphasising the importance of the shin segment’s orientation in space, four distinctive key positions are presented (‘shin block’, ‘touchdown’, ‘heel lock’ and ‘propulsion pose’), which are linked by a progressive ‘shin roll’ motion during swing-stance transition. The shin’s downward tilt is driven by three different movement strategies (‘shin alignment’, ‘horizontal ankle rocker’ and ‘shin drop’). The tilt’s optimal amount and timing will contribute to a mechanically efficient acceleration via timely staggered proximal-to-distal power output. Empirical data obtained from athletes of different performance levels and sporting backgrounds are required to verify the feasibility of this concept. The framework presented here should facilitate future biomechanical analyses and may enable coaches and practitioners to develop specific training programs and feedback strategies to provide athletes with a more efficient acceleration technique.
Die vorliegende Bachelorarbeit befasst sich mit den Marketing-Kommunikationsstrategien im zweiseitigen Markt am Beispiel einer Immobilienplattform.
Das primäre Ziel dieser Arbeit besteht darin, auf Grundlage der Netzwerkeffekte im zweiseitigen Markt und durch Anwendung von Onlinemarketingmaßnahmen die Positionierung der Plattform Immobilien Rith in den Internetsuchergebnissen zu optimieren.
MINT-College TIEFE
(2021)
Das Projekt MINT-College TIEFE konnte in der zweiten Förderperiode die verschiedenen Maßnahmen der vorangegangenen Förderperiode weiter ausbauen und verstetigen. Die Angebote im Rahmen des Projekts MINT-College TIEFE begleiteten die Studierenden über den Student-Life-Cycle hinweg über das komplette Studium der technischen Studiengänge, beginnend in der Schule und endend beim Übergang in den Beruf. Um die Qualität der Lehre an der Hochschule Offenburg zu verbessern, wurden darüber hinaus verschiedene digital unterstützte Lehrformate weiterentwickelt und ausgebaut. Zentrale Angebote des MINT-College, das 2019 zentrale Einrichtung der Hochschule Offenburg wurde, sind die für die Studieneingangsphase entwickelten Angebote der Einführungstage, des Mentorenprogramms, der Brückenkurse, des Lernzentrums und Angebote für den Übergang in den Beruf, wie das Gründerbüro. Die mediendidaktischen Unterstützungsangebote für Lehrende unterstützten den Lernkulturwandel an der Hochschule. Es wurden systematisch nachhaltige Strukturen aufgebaut, um Innovationen für das Lehren und das Lernen auch künftig entwickeln, erproben und etablieren zu können.
The central purpose of this paper is to present a novel framework supporting the specification and the implementation of media streaming services using XML and Java Media Framework (JMF). It provides an integrated service development environment comprising of a streaming service model, a service specification language and several implementation and retrieval tools. Our approach is based on a clear separation of a streaming service specification, and its implementation by a distributed JMF application and can be used for different streaming paradigms, e.g. push and pull services.
The central purpose of this paper is to present a novel framework supporting the specification, the implementation and retrieval of media streaming services. It provides an integrated service development environment comprising of a streaming service model, a service specification language and several implementation and retrieval tools. Our approach is based on a clear separation of a streaming service specification, and its implementation by a distributed application and can be used for different streaming paradigms, e.g. push and pull services.
Purpose
Although start-ups have gained increasing scholarly attention, we lack sufficient understanding of their entrepreneurial strategic posture (ESP) in emerging economies. The purpose of this study is to examine the processes of ESP of new technology venture start-ups (NTVs) in an emerging market context.
Design/methodology/approach
In line with grounded theory guidelines and the inductive research traditions, the authors adopted a qualitative approach involving 42 in-depth semi-structured interviews with Ghanaian NTV entrepreneurs to gain a comprehensive analysis at the micro-level on the entrepreneurs' strategic posturing. A systematic procedure for data analysis was adopted.
Findings
From the authors' analysis of Ghanaian NTVs, the authors derived a three-stage model to elucidate the nature and process of ESP Phase 1 spotting and exploiting market opportunities, Phase II identifying initial advantages and Phase III ascertaining and responding to change.
Originality/value
The study contributes to advancing research on ESP by explicating the process through which informal ties and networks are utilised by NTVs and NTVs' founders to overcome extreme resource constraints and information vacuums in contexts of institutional voids. The authors depart from past studies in demonstrating how such ties can be harnessed in spotting and exploiting market opportunities by NTVs. On this basis, the paper makes original contributions to ESP theory and practice.
One of the main problematics of the seals tests is the time and money consuming they are. Up to now, there are few tries to do a digitalisation of a test where the seals behaviour can be known.
This work aims to digitally reproduce a seal test to extract their behaviour when working under different operation conditions to see their impact on the pimp’s efficiency. In this thesis, due to the Lomaking effect, the leakage and the forces applied on the stator will be the base of analysis.
First of all, among all the literature available for very different kind of seals and inner patterns, it has been chosen the most appropriate and precise data. The data chosen is “Test results for liquid Damper Seals using a Round-Hole Roughness Pattern for the Stator” from Fayolle, P. and “Static and Rotordynamic Characteristics of Liquid Annular Seals with Circumferentially/Grooved Stator and Smooth Rotor using three levels of circumferential Inlet-Fluid” from Torres J.M.
From the literature, dimensions of the test rig and the seals will be extracted to model them into a 3D CAD software. With the 3D CAD digitalisation, the fluid volumes for a rotor-centred position, meaning without eccentricity, will be extracted, and used. The following components have been modelled:
- Smooth Annular Liquid Seal (Grooved Rotor)
- Grooved Annular Liquid Seal (Smooth Rotor)
- Round-Hole Pattern Annular Liquid Seal (𝐻𝑑=2 𝑚𝑚) (Smooth Rotor)
- Straight Honeycomb Annular Liquid Seal (Smooth Rotor)
- Convergent Honeycomb Annular Liquid Seal (Smooth Rotor)
- Smooth Rotor / Smooth Annular Liquid Seal (Smooth Rotor)
As there is just one test rig, all the components have been adapted to the different dimensions of the seals by referencing some measures. This allows to test any seal with the same test rig.
Afterwards a CFD simulation that will be used to obtain leakage and stator forces. The parameters that will be changed are the rotational velocity of the fluid (2000 rpm, 4000 rpm, and 6000 rpm) and the pressure drop (2,068 bar, 4,137 bar, 6,205 bar, and 8,274 bar).
Those results will be compared to the literature ones, and they will determine if digitalisation can be validated or not. Even though the relative error is higher than 5% but the tendency is the same and it is thought that by changing some parameters the test results can be even closer to the literature ones.
The evolution of cellular networks from its first generation (1G) to its fourth generation (4G) was driven by the demand of user-centric downlink capacity also technically called Mobile Broad-Band (MBB). With its fifth generation (5G), Machine Type Communication (MTC) has been added into the target use cases and the upcoming generation of cellular networks is expected to support them. However, such support requires improvements in the existing technologies in terms of latency, reliability, energy efficiency, data rate, scalability, and capacity.
Originally, MTC was designed for low-bandwidth high-latency applications such as, environmental sensing, smart dustbin, etc. Nowadays there is an additional demand around applications with low-latency requirements. Among other well-known challenges for recent cellular networks such as data rate energy efficiency, reliability etc., latency is also not suitable for mission-critical applications such as real-time control of machines, autonomous driving, tactile Internet etc. Therefore, in the currently deployed cellular networks, there is a necessity to reduce the latency and increase the reliability offered by the networks to support use cases such as, cooperative autonomous driving or factory automation, that are grouped under the denomination Ultra-Reliable Low-Latency Communication (URLLC).
This thesis is primarily concerned with the latency into the Universal Terrestrial Radio Access Network (UTRAN) of cellular networks. The overall work is divided into five parts. The first part presents the state of the art for cellular networks. The second part contains a detailed overview of URLLC use cases and the requirements that must be fulfilled by the cellular networks to support them. The work in this thesis is done as part of a collaboration project between IRIMAS lab in Université de Haute-Alsace, France and Institute for Reliable Embedded Systems and Communication Electronics (ivESK) in Offenburg University of Applied Sciences, Germany. The selected use cases of URLLC are part of the research interests of both partner institutes. The third part presents a detailed study and evaluation of user- and control-plane latency mechanisms in current generation of cellular networks. The evaluation and analysis of these latencies, performed with the open-source ns-3 simulator, were conducted by exploring a broad range of parameters that include among others, traffic models, channel access parameters, realistic propagation models, and a broad set of cellular network protocol stack parameters. These simulations were performed with low-power, low-cost, and wide-range devices, commonly called IoT devices, and standardized for cellular networks. These devices use either LTE-M or Narrowband-IoT (NB-IoT) technologies that are designed for connected things. They differ mainly by the provided bandwidth and other additional characteristics such as coding scheme, device complexity, and so on.
The fourth part of this thesis shows a study, an implementation, and an evaluation of latency reduction techniques that target the different layers of the currently used Long Term Evolution (LTE) network protocol stack. These techniques based on Transmission Time Interval (TTI) reduction and Semi-Persistent Scheduling (SPS) methods are implemented into the ns-3 simulator and are evaluated through realistic simulations performed for a variety of low-latency use cases focused on industry automation and vehicular networking. For testing the proposed latency reduction techniques in cellular networks, since ns-3 does not support NB-IoT in its current release, an NB-IoT extension for LTE module was developed. This makes it possible to explore deployment limitations and issues.
In the last part of this thesis, a flexible deployment framework called Hybrid Scheduling and Flexible TTI for the proposed latency reduction techniques is presented, implemented and evaluated through realistic simulations. With help of the simulation evaluation, it is shown that the improved LTE network proposed and implemented in the simulator can support low-latency applications with low cost, higher range, and narrow bandwidth devices. The work in this thesis points out the potential improvement techniques, their deployment issues and paves the way towards the support for URLLC applications with upcoming cellular networks.
Fifth-generation (5G) cellular mobile networks are expected to support mission-critical low latency applications in addition to mobile broadband services, where fourth-generation (4G) cellular networks are unable to support Ultra-Reliable Low Latency Communication (URLLC). However, it might be interesting to understand which latency requirements can be met with both 4G and 5G networks. In this paper, we discuss (1) the components contributing to the latency of cellular networks and (2) evaluate control-plane and user-plane latencies for current-generation narrowband cellular networks and point out the potential improvements to reduce the latency of these networks, (3) present, implement and evaluate latency reduction techniques for latency-critical applications. The two elements we detected, namely the short transmission time interval and the semi-persistent scheduling are very promising as they allow to shorten the delay to processing received information both into the control and data planes. We then analyze the potential of latency reduction techniques for URLLC applications. To this end, we develop these techniques into the long term evolution (LTE) module of ns-3 simulator and then evaluate the performance of the proposed techniques into two different application fields: industrial automation and intelligent transportation systems. Our detailed evaluation results from simulations indicate that LTE can satisfy the low-latency requirements for a large choice of use cases in each field.
The excessive control signaling in Long Term Evolution networks required for dynamic scheduling impedes the deployment of ultra-reliable low latency applications. Semi-persistent scheduling was originally designed for constant bit-rate voice applications, however, very low control overhead makes it a potential latency reduction technique in Long Term Evolution. In this paper, we investigate resource scheduling in narrowband fourth generation Long Term Evolution networks through Network Simulator (NS3) simulations. The current release of NS3 does not include a semi-persistent scheduler for Long Term Evolution module. Therefore, we developed the semi-persistent scheduling feature in NS3 to evaluate and compare the performance in terms of uplink latency. We evaluate dynamic scheduling and semi-persistent scheduling in order to analyze the impact of resource scheduling methods on up-link latency.
Vehicle-to-Everything (V2X) communication promises improvements in road safety and efficiency by enabling low-latency and reliable communication services for vehicles. Besides using Mobile Broadband (MBB), there is a need to develop Ultra Reliable Low Latency Communications (URLLC) applications with cellular networks especially when safety-related driving applications are concerned. Future cellular networks are expected to support novel latencysensitive use cases. Many applications of V2X communication, like collaborative autonomous driving requires very low latency and high reliability in order to support real-time communication between vehicles and other network elements. In this paper, we classify V2X use-cases and their requirements in order to identify cellular network technologies able to support them. The bottleneck problem of the medium access in 4G Long Term Evolution(LTE) networks is random access procedure. It is evaluated through simulations to further detail the future limitations and requirements. Limitations and improvement possibilities for next generation of cellular networks are finally detailed. Moreover, the results presented in this paper provide the limits of different parameter sets with regard to the requirements of V2X-based applications. In doing this, a starting point to migrate to Narrowband IoT (NB-IoT) or 5G - solutions is given.
The next generation cellular networks are expected to improve reliability, energy efficiency, data rate, capacity and latency. Originally, Machine Type Communication (MTC) was designed for low-bandwidth high-latency applications such as, environmental sensing, smart dustbin, etc., but there is additional demand around applications with low latency requirements, like industrial automation, driver-less cars, and so on. Improvements are required in 4G Long Term Evolution (LTE) networks towards the development of next generation cellular networks for providing very low latency and high reliability. To this end, we present an in-depth analysis of parameters that contribute to the latency in 4G networks along with a description of latency reduction techniques. We implement and validate these latency reduction techniques in the open-source network simulator (NS3) for narrowband user equipment category Cat-Ml (LTE-M) to analyze the improvements. The results presented are a step towards enabling narrowband Ultra Reliable Low Latency Communication (URLLC) networks.
On a regular basis, we hear of well-known online services that have been abused or compromised as a result of data theft. Because insecure applications jeopardize users' privacy as well as the reputation of corporations and organizations, they must be effectively secured from the outset of the development process. The limited expertise and experience of involved parties, such as web developers, is frequently cited as a cause of risky programs. Consequently, they rarely have a full picture of the security-related decisions that must be made, nor do they understand how these decisions affect implementation accurately.
The selection of tools and procedures that can best assist a certain situation in order to protect an application against vulnerabilities is a critical decision. Regardless of the level of security that results from adhering to security standards, these factors inadvertently result in web applications that are insufficiently secured. JavaScript is a language that is heavily relied on as a mainstream programming language for web applications with several new JavaScript frameworks being released every year.
JavaScript is used on both the server-side in web applications development and the client-side in web browsers as well.
However, JavaScript web programming is based on a programming style in which the application developer can, and frequently must, automatically integrate various bits of code from third parties. This potent combination has resulted in a situation today where security issues are frequently exploited. These vulnerabilities can compromise an entire server if left unchecked. Even though there are numerous ad hoc security solutions for web browsers, client-side attacks are also popular. The issue is significantly worse on the server side because the security technologies available for server-side JavaScript application frameworks are nearly non-existent.
Consequently, this thesis focuses on the server-side aspect of JavaScript; the development and evaluation of robust server-side security technologies for JavaScript web applications. There is a clear need for robust security technologies and security best practices in server-side JavaScript that allow fine-grained security.
However, more than ever, there is this requirement of reducing the associated risks without hindering the web application in its functionality.
This is the problem that will be tackled in this thesis: the development of secure security practices and robust security technologies for JavaScript web applications, specifically, on the server-side, that offer adequate security guarantees without putting too many constraints on their functionality.
Integration of BACNET OPC UA-Devices Using a JAVA OPC UA SDK Server with BACNET Open Source Library
(2014)
In dieser Bachelorthesis wurde ein Funktionsmuster eines energieautarken elektronischen Türschildes mit einem 7,8” großen E-Paper-Display und NFC-Konfigurationsschnittstelle entwickelt, auf dem per Smartphone-App und NFC einfach Informationen wie Abwesendheitsnachrichten angezeigt werden können. Hierzu wird ein Kommunikationsprotokoll entwickelt, welches die Kommunikation zwischen App und Türschild spezifiziert, und einen Befehlssatz zur Konfiguration des Türschildes bereitstellt. Das System wird aus amorphen Silizium-Solarzellen versorgt und verfügt über einen LiPo-Akku als Energiespeicher. Durch sorgfältiges Hardware- und Software-seitiges Low-Power-Design beträgt die Leistungsaufnahme im Ruhemodus lediglich 1, 5 μW. Bedingt durch den anwenderfreundlichen, jedoch für Low-Power-Designs ungeeigneten Display-Controller, beträgt der Energieverbrauch während eines Updates 300 mW. Trotzdem zeigt sich, dass das System bei einer Zellfläche von knapp 220 cm2 auch bei schlechter Beleuchtung von 10 lx in dunklen Gängen mehrere Türschild-Updates pro Tag bereitstellen kann.
Elektronische Türschilder zur Darstellung von Informationen sind insbesondere in öffentlichen Gebäuden zwischenzeitlich weit verbreitet. Die Varianz dieser elektronischen Türschilder reicht vom Tablet-basierten Türschild bis hin zum PC-basierten Türschild mit externem Bildschirm. Zumeist werden die Systeme mit 230 V betrieben. Bei einer großen Summe von Türschildern in öffentlichen Gebäuden kann dies zu einem signifikanten Umsatz an Energie führen. Im Rahmen dieses Papers wird die Entwicklung eines energieautarken arbeiten Türschildes vorgestellt, bei dem ein E-Paper-Display zum Einsatz kommt. Das Türschild lässt sich per Smartphone-App und NFC-Schnittstelle konfigurieren. Es wird insbesondere auf das Low-Power-Hardware-Design der Elektronik und energetische Aspekte eingegangen.
When people with hearing loss are provided with different devices in each ear, these devices usually have different processing latencies. This leads to static temporal offsets between both ears in the order of several milliseconds. This thesis measured effects of such offsets in stimulation timing on mechanisms of binaural hearing, such as sound localization and speech understanding in noise in hearing-impaired and normal-hearing listeners.
Subjects utilizing a cochlear implant (CI) in one ear and a hearing aid (HA) on the contralateral ear suffer from mismatches in stimulation timing due to different processing latencies of both devices. This device delay mismatch leads to a temporal mismatch in auditory nerve stimulation. Compensating for this auditory nerve stimulation mismatch by compensating for the device delay mismatch can significantly improve sound source localization accuracy. One CI manufacturer has already implemented the possibility of mismatch compensation in its current fitting software. This study investigated if this fitting parameter can be readily used in clinical settings and determined the effects of familiarization to a compensated device delay mismatch over a period of 3–4 weeks. Sound localization accuracy and speech understanding in noise were measured in eleven bimodal CI/HA users, with and without a compensation of the device delay mismatch. The results showed that sound localization bias improved to 0°, implying that the localization bias towards the CI was eliminated when the device delay mismatch was compensated. The RMS error was improved by 18% with this improvement not reaching statistical significance. The effects were acute and did not further improve after 3 weeks of familiarization. For the speech tests, spatial release from masking did not improve with a compensated mismatch. The results show that this fitting parameter can be readily used by clinicians to improve sound localization ability in bimodal users. Further, our findings suggest that subjects with poor sound localization ability benefit the most from the device delay mismatch compensation.
Users of a cochlear implant (CI) in one ear, who are provided with a hearing aid (HA) in the contralateral ear, so-called bimodal listeners, are typically affected by a constant and relatively large interaural time delay offset due to differences in signal processing and differences in stimulation. For HA stimulation, the cochlear travelling wave delay is added to the processing delay, while for CI stimulation, the auditory nerve fibers are stimulated directly. In case of MED-EL CI systems in combination with different HA types, the CI stimulation precedes the acoustic HA stimulation by 3 to 10 ms. A self-designed, battery-powered, portable, and programmable delay line was applied to the CI to reduce the device delay mismatch in nine bimodal listeners. We used an A-B-B-A test design and determined if sound source localization improves when the device delay mismatch is reduced by delaying the CI stimulation by the HA processing delay (τ HA ). Results revealed that every subject in our group of nine bimodal listeners benefited from the approach. The root-mean-square error of sound localization improved significantly from 52.6° to 37.9°. The signed bias also improved significantly from 25.2° to 10.5°, with positive values indicating a bias toward the CI. Furthermore, two other delay values (τ HA –1 ms and τ HA +1 ms) were applied, and with the latter value, the signed bias was further reduced in some test subjects. We conclude that sound source localization accuracy in bimodal listeners improves instantaneously and sustainably when the device delay mismatch is reduced.
In asymmetric treatment of hearing loss, processing latencies of the modalities typically differ. This often alters the reference interaural time difference (ITD) (i.e., the ITD at 0° azimuth) by several milliseconds. Such changes in reference ITD have shown to influence sound source localization in bimodal listeners provided with a hearing aid (HA) in one and a cochlear implant (CI) in the contralateral ear. In this study, the effect of changes in reference ITD on speech understanding, especially spatial release from masking (SRM) in normal-hearing subjects was explored. Speech reception thresholds (SRT) were measured in ten normal-hearing subjects for reference ITDs of 0, 1.75, 3.5, 5.25 and 7 ms with spatially collocated (S0N0) and spatially separated (S0N90) sound sources. Further, the cues for separation of target and masker were manipulated to measure the effect of a reference ITD on unmasking by A) ITDs and interaural level differences (ILDs), B) ITDs only and C) ILDs only. A blind equalization-cancellation (EC) model was applied to simulate all measured conditions. SRM decreased significantly in conditions A) and B) when the reference ITD was increased: In condition A) from 8.8 dB SNR on average at 0 ms reference ITD to 4.6 dB at 7 ms, in condition B) from 5.5 dB to 1.1 dB. In condition C) no significant effect was found. These results were accurately predicted by the applied EC-model. The outcomes show that interaural processing latency differences should be considered in asymmetric treatment of hearing loss.
Bei bimodaler Cochlea-Implantat-/Hörgerät-Versorgung kann es aufgrund seitenverschiedener Signalverarbeitung zu einer zeitlich versetzten Stimulation der beiden Modalitäten kommen. Jüngste Studien haben gezeigt, dass durch zeitlichen Abgleich der Modalitäten die Schalllokalisation bei bimodaler Versorgung verbessert werden kann. Um solch einen Abgleich vornehmen zu können, ist die messtechnische Bestimmung der Durchlaufzeit von Hörgeräten erforderlich. Kommerziell verfügbare Hörgerätemessboxen können diese Werte häufig liefern. Die dazu verwendete Signalverarbeitung wird dabei aber oft nicht vollständig offengelegt. In dieser Arbeit wird ein alternativer und nachvollziehbarer Ansatz zum Design eines simplen Messaufbaus basierend auf einem Arduino DUE Mikrocontroller-Board vorgestellt. Hierzu wurde ein Messtisch im 3D-Druck gefertigt, auf welchem Hörgeräte über einen 2-ccm-Kuppler an ein Messmikrofon angeschlossen werden können. Über einen Latenzvergleich mit dem simultan erfassten Signal eines Referenzmikrofons kann die Durchlaufzeit von Hörgeräten bestimmt werden. Frequenzspezifische Durchlaufzeiten werden mittels einer Kreuzkorrelation zwischen Ziel- und Referenzsignal errechnet. Aufnahme, Ausgabe und Speicherung der Signale erfolgt über einen ATMEL SAM3X8E Mikrocontroller, welcher auf dem Arduino DUE-Board verbaut ist. Über eigens entworfene elektronische Schaltungen werden die Mikrofone und der verwendete Lautsprecher angesteuert. Nach Abschluss einer Messung (Messdauer ca. 5 s) werden die Messdaten seriell an einen PC übertragen, auf dem die Datenauswertung mittels MATLAB erfolgt. Erste Validierungen zeigten eine hohe Stabilität der Messergebnisse mit sehr geringen Standardabweichungen im Bereich weniger Mikrosekunden für Pegel zwischen 50 und 75 dB (A). Der Messaufbau wird in laufenden Studien zur Quantifizierung der Durchlaufzeit von Hörgeräten verwendet.
Though the basic concept of a ledger that anyone can view and verify has been around for quite some time, today’s blockchains bring much more to the table including a way to incentivize users. The coins given to the miner or validator were the first source of such incentive to make sure they fulfilled their duties. This thesis draws inspiration from other peer efforts and uses this same incentive to achieve certain goals. Primarily one where users are incentivised to discuss their opinions and find scientific or logical backing for their standpoint. While traditional chains form a consensus on a version of financial "truth", the same can be applied to ideological truths too. To achieve this, creating a modified or scaled proof of stake consensus mechanism is explored in this work. This new consensus mechanism is a Reputation Scaled - Proof of Stake. This reputation can be built over time by voting for the winning side consistently or by sticking to one’s beliefs strongly. The thesis hopes to bridge the gap in current consensus algorithms and incentivize critical reasoning.
The increase of the Internet of Things (IoT) calls for secure solutions for industrial applications. The security of IoT can be potentially improved by blockchain. However, blockchain technology suffers scalability issues which hinders integration with IoT. Solutions to blockchain’s scalability issues, such as minimizing the computational complexity of consensus algorithms or blockchain storage requirements, have received attention. However, to realize the full potential of blockchain in IoT, the inefficiencies of its inter-peer communication must also be addressed. For example, blockchain uses a flooding technique to share blocks, resulting in duplicates and inefficient bandwidth usage. Moreover, blockchain peers use a random neighbor selection (RNS) technique to decide on other peers with whom to exchange blockchain data. As a result, the peer-to-peer (P2P) topology formation limits the effective achievable throughput. This paper provides a survey on the state-of-the-art network structures and communication mechanisms used in blockchain and establishes the need for network-based optimization. Additionally, it discusses the blockchain architecture and its layers categorizes existing literature into the layers and provides a survey on the state-of-the-art optimization frameworks, analyzing their effectiveness and ability to scale. Finally, this paper presents recommendations for future work.
Lean und ERP - Synergie oder Widerspruch? Ein neuer Ansatz zur Steigerung der Unternehmenseffizienz
(2015)
Eine erfolgreiche Zusammenführung der Vorteile von ERP-Systemen mit den Vorzügen des Lean-Ansatzes kann zur Erschließung eines erheblichen Verbesserungspotenzials und damit zu signifikanten Wettbewerbsvorteilen einer Unternehmung führen. Da dieser Ansatz in der Praxis häufig kritisiert und bisher kaum adäquat verfolgt wird, zielt dieser Beitrag darauf ab, einen innovativen Lösungsweg vorzustellen, welcher nicht nur theoretisch, sondern auch anhand eines ERP-Einführungsprojekts in einem KMU empirisch aufzeigt, dass Lean und ERP nutzbringend miteinander kombiniert werden können und sollten.
The present document is aimed to propose a suitable thermal model for the cooling down process of a one piston air cooled reciprocating compressor. In order to achieve this, a thermographic camera is used to record the temperature of different measuring points throughout different operating conditions. This data is later analyzed, with statistical tools and graphical visualization. The thermal phenomena present in the thermal process is characterized according to the compressors' geometry. Finally, using the analysis and taking into consideration the thermal phenomena the optimal thermal model is selected. This paper belongs to a bigger project and the last step is to simulate the compressor and the accuracy of the proposed model.
Although short range wireless communication explicitly targets local and very regional applications, range continues to be an extremely important issue. The range directly depends on the so called link budget, which can be increased by the choice of modulation and coding schemes. Especially, the recent transceiver generation comes with extensive and flexible support for Software Defined Radio (SDR). The SX127x family from Semtech Corp. is a member of this device class and promises significant benefits for range, robust performance, and battery lifetime compared to competing technologies. This contribution gives a short overview into the technologies to support Long Range (LoRa ™), describes the outdoor setup at the Laboratory Embedded Systems and Communication Electronics of Offenburg University of Applied Sciences, shows detailed measurement results and discusses the strengths and weaknesses of this technology.
Die vorliegende Bachelor-Thesis wurde im Rahmen des Bachelorstudiengangs an der Hochschule Offenburg in der Sparte S der Fertigungsplanung der Hugo Kern und Liebers GmbH und Co. KG verfasst. Ziel dieser Abschlussarbeit ist es, die Lagerung der vorderen Kettenumlenkung weiter zu optimieren, um die Standzeit zu verbessern. Der Fokus der Arbeit liegt dabei in der Optimierung des Seriengleitlagers, bzw. der Entwicklung und Herstellung eines speziell gekapselten Gleitlagers.
Als Optimierungen im seriennahen Bereich, das heißt möglichst ohne große Änderungen am Fertigungs- bzw. Montageablauf, findet vor allem das Borieren der Reibpartner besondere Beachtung. Durch erste Feldversuche zeigte sich, dass das Borieren des Umlenksterns positive Auswirkungen auf die Reibung hat und den Widerstand gegen abrasiven Verschleiß durch Erhöhung der Randschichthärte deutlich verbessert. Zusätzlich zum Einsatz eines borierten Umlenksterns wird untersucht, ob das zusätzliche Borieren des HM-Rings weitere Vorteile bringt, vor allem hinsichtlich der entstehenden zusätzlichen Notlaufeigenschaften durch die Boridschicht.
Als weitere Variante wird der eingesetzte Hartmetallring, welcher aktuell lediglich eine einzige Schmiernut enthält, mit optimierten Schmiernuten hergestellt. Als Vorbild hierfür wird die Gestaltungsrichtlinie von Schmiernuten von hydrodynamischen Gleitlagern verwendet.
Der größte Block und damit auch der, welcher am vielversprechendsten ist, ist die Neuentwicklung und Herstellung einer gekapselten Gleitlagervariante. Diese soll es ermöglichen, dass die Reibpartner komplett von Öl umschlossen sind und so eine Verbesserte und dauerhafte Schmierung erreicht werden soll. Außerdem soll die gekapselte Gleitlagerung so gestaltet werden, dass eine Nachförderung von Öl aus einem in den Bolzen angebrachten Schmiermittelreservoir ermöglicht wird und so eine Lebensdauerschmierung erreicht werden kann.
Um die unterschiedlichen Mustervariationen bewerten zu können, werden jeweils Prüfstandversuche durchgeführt, bei dem die entstehenden Drehmomente und die Temperatur gemessen werden. Als Vergleich dient jeweils der Serienstand mit seinen festgelegten Grenzen.
Außerdem wird für jede Variante ein Sägeversuch durchgeführt, bei welchem die Bau-gruppen bei den beiden kritischen Sägerichtungen Rückwärts und Einstechen überprüft wird. Auch hier erfolgt die Beurteilung über etwaige Verbesserungen mit den Ergebnissen der Sägesysteme aus dem aktuellen Serienzustand.
Bei der Prüfung der Musterbaugruppen zeigt sich, dass vor allem das Borieren der Reibpartner Vorteile gegenüber der Serie bringt und durchaus die Möglichkeit der Umsetzung in der Serienbaugruppe besteht. Die Tests verliefen äußerst positiv, vor allem im Bereich höherer Belastungen zeigt sich, dass das Borieren des Umlenksterns deutliches Verbesserungspotenzial im Vergleich zum aktuellen Serienstand zeigt.
An ein Umsetzen der Baugruppen mit gekapselter Gleitlagervariante ist aktuell nicht zu denken. Die geprüften Baugruppen zeigen deutliche Schwächen bei den Prüfstandsversuchen. Die Ergebnisse der Sägeversuche stellen sich jedoch noch deutlich schlechter dar. Unabhängig vom verwendeten Schmieröl, bzw. den darin enthaltenen Festschmierstoffpartikeln, besteht keine einzige Baugruppe auch nur annähernd die festgelegten Mindestanforderungen.
Um die gekapselte Gleitlagervariante auf einen Stand zu bringen, bei welchem an ein Umsetzen in die Serienbaugruppe gedacht werden kann, bedarf es noch weiterem Entwicklungsaufwand. Das Aufbiegen des Schwertes während des Sägens muss verhindert werden. Außerdem muss die Materialpaarung, die Härte und die Oberflächenqualität von Umlenkstern und Bolzen angepasst werden, um die Ausbildung von Kaltverschweißungen zu vermeiden. Die Kaltverschweißungen zwischen Umlenkstern und Bolzen bewirken, dass der Bolzen nicht mehr drehbar ist was unmittelbar zum Ausfall der Baugruppen führt.
Ripple: Overview and Outlook
(2015)
Ripple is a payment system and a digital currency which evolved completely independently of Bitcoin. Although Ripple holds the second highest market cap after Bitcoin, there are surprisingly no studies which analyze the provisions of Ripple.
In this paper, we study the current deployment of the Ripple payment system. For that purpose, we overview the Ripple protocol and outline its security and privacy provisions in relation to the Bitcoin system. We also discuss the consensus protocol of Ripple. Contrary to the statement of the Ripple designers, we show that the current choice of parameters does not prevent the occurrence of forks in the system. To remedy this problem, we give a necessary and sufficient condition to prevent any fork in the system. Finally, we analyze the current usage patterns and trade dynamics in Ripple by extracting information from the Ripple global ledger. As far as we are aware, this is the first contribution which sheds light on the current deployment of the Ripple system.
Social-Media-Content - Auswirkungen auf Fear of Missing Out und den Selbstwert junger Nutzer*innen
(2023)
Social-Media-Marketing ist ein wichtiger Baustein einer erfolgreichen Content-Strategie. Insbesondere jüngere Zielgruppen sind auf Social Media anzutreffen – und das oftmals über viele Stunden täglich. Neben den Vorteilen, die Social Media den Nutzer*innen bietet, gibt es aber auch Schattenseiten. Zwei negative Aspekte, die sogenannte Fear of Missing Out und ein verminderter Selbstwert, wurden im Frühjahr 2022 in einer empirischen Befragung von 1338 Personen zwischen 14 und 30 Jahren untersucht. Daneben wurden auch Daten zum grundsätzlichen Social-Media-Nutzungsverhalten erhoben. Die zentralen Erkenntnisse, die sich aus der Studie ableiten, werden in diesem Kapitel vorgestellt und mit Bezug auf ihre Relevanz für das Content-Marketing hin eingeordnet.
Das Thema Ethnomarketing gewinnt mit der steigenden Anzahl an Mitbürgern mit Migrationshintergrund an Wert. Bestimmte Marketingmaßnahmen für bestimmte Zielgruppen. Diese wissenschaftliche Arbeit befasst sich mit diesem Thema und die Widerspiegelung (Medienintegration) dieser in den Medien. Anhand von verschiedenen Beispielen wird das Thema überschaubar und verständlich beleuchtet.
Investigation on Bowtie Antennas Operating at Very Low Frequencies for Ground Penetrating Radar
(2023)
The efficiency of Ground Penetrating Radar (GPR) systems significantly depends on the antenna performance as the signal has to propagate through lossy and inhomogeneous media. GPR antennas should have a low operating frequency for greater penetration depth, high gain and efficiency to increase the receiving power and should be compact and lightweight for ease of GPR surveying. In this paper, two different designs of Bowtie antennas operating at very low frequencies are proposed and analyzed.
The objective of this project is to enhance the operations of a micro-enterprise that deals with food ingredients. The emphasis is on streamlining procedures and executing effective tactics. By utilizing tools like SWOT analysis, evaluations, and strategy development, the company's strengths, weaknesses, opportunities, and threats were assessed. The company developed business-level and functional-level strategies to expedite growth and attain objectives based on the findings. Moreover, precise suggestions were given to minimize the quantity of SKUs and optimize operations. The work highlighted the significance of developing a process map for streamlining operations, boosting efficiency, and elevating customer contentment. Through the implementation of said recommendations and strategies, the company can strategically position itself for success within the highly competitive food ingredients industry.
The progress in machine learning has led to advanced deep neural networks. These networks are widely used in computer vision tasks and safety-critical applications. The automotive industry, in particular, has experienced a significant transformation with the integration of deep learning techniques and neural networks. This integration contributes to the realization of autonomous driving systems. Object detection is a crucial element in autonomous driving. It contributes to vehicular safety and operational efficiency. This technology allows vehicles to perceive and identify their surroundings. It detects objects like pedestrians, vehicles, road signs, and obstacles. Object detection has evolved from being a conceptual necessity to an integral part of advanced driver assistance systems (ADAS) and the foundation of autonomous driving technologies. These advancements enable vehicles to make real-time decisions based on their understanding of the environment, improving safety and driving experiences. However, the increasing reliance on deep neural networks for object detection and autonomous driving has brought attention to potential vulnerabilities within these systems. Recent research has highlighted the susceptibility of these systems to adversarial attacks. Adversarial attacks are well-designed inputs that exploit weaknesses in the deep learning models underlying object detection. Successful attacks can cause misclassifications and critical errors, posing a significant threat to the functionality and safety of autonomous vehicles. With the rapid development of object detection systems, the vulnerability to adversarial attacks has become a major concern. These attacks manipulate inputs to deceive the target system, significantly compromising the reliability and safety of autonomous vehicles. In this study, we focus on analyzing adversarial attacks on state-of-the-art object detection models. We create adversarial examples to test the models’ robustness. We also check if the attacks work on a different object detection model meant for similar tasks. Additionally, we extensively evaluate recent defense mechanisms to see how effective they are in protecting deep neural networks (DNNs) from adversarial attacks and provide a comprehensive overview of the most commonly used defense strategies against adversarial attacks, highlighting how they can be implemented practically in real-world situations.
In this paper we integrate the ideas of network coding and relays into an existing practical network architecture used in a wireless network scenario. Specifically, we use the COPE architecture to test our ideas. Since previous works have focused on the communication aspect at the physical layer level, we attempt to take it one step further by including the MAC layer. Our idea is based on information theoretic concepts developed by Shannon in order to reliably apply network coding to increase the net throughput.
Supporting the COVID-19 response in Asia and the Pacific—The role of the Asian Development Bank.
(2020)
The COVID-19 pandemic has affected all countries of the Asia Pacific region over the last few months with far reaching economic, health and social consequences. To counter the impact, governments have accelerated their health spending and announced large macroeconomic stabilization and stimulus policy packages. As with past disasters and crises in the region, the Asian Development Bank has reacted with a number of targeted support interventions since the very early stages of the outbreak. In mid- April 2020, the Bank then put forward a comprehensive COVID-19 Response Package totalling $20 billion to support its member countries which rests on four pillars.
The last few months have proven that multilateral development banks like the Asian Development Bank have the ability to respond quickly and to mobilize significant resources for a global emergency like COVID-19. Whilst this financial supported is urgently needed at this point, attention will need to be paid on how debt sustainability for low- and middle-income countries can be ensured in the coming years. Given the unprecedented scale of and uncertainty around the COVID-19 pandemic, it may offer a window of opportunity to redesign the way developmental finance is coordinated and the way it is delivered. This also includes a chance to “build back better” and to focus on a sustainable, resilient and green recovery.
Experimental Investigation of the Air Exchange Effectiveness of Push-Pull Ventilation Devices
(2020)
The increasing installation numbers of ventilation units in residential buildings are driven by legal objectives to improve their energy efficiency. The dimensioning of a ventilation system for nearly zero energy buildings is usually based on the air flow rate desired by the clients or requested by technical regulations. However, this does not necessarily lead to a system actually able to renew the air volume of the living space effectively. In recent years decentralised systems with an alternating operation mode and fairly good energy efficiencies entered the market and following question was raised: “Does this operation mode allow an efficient air renewal?” This question can be answered experimentally by performing a tracer gas analysis. In the presented study, a total of 15 preliminary tests are carried out in a climatic chamber representing a single room equipped with two push-pull devices. The tests include summer, winter and isothermal supply air conditions since this parameter variation is missing till now for push-pull devices. Further investigations are dedicated to the effect of thermal convection due to human heat dissipation on the room air flow. In dependence on these boundary conditions, the determined air exchange efficiency varies, lagging behind the expected range 0.5 < εa < 1 in almost all cases, indicating insufficient air exchange including short-circuiting. Local air exchange values suggest inhomogeneous air renewal depending on the distance to the indoor apertures as well as the temperature gradients between in- and outdoor. The tested measurement set-up is applicable for field measurements.
Durch ein wachsendes Bewusstsein für soziale und nachhaltige Konflikte spielt verantwortungsvolles unternehmerisches Handeln eine zunehmend große Rolle für potenzielle Kund*innen. Viele Unternehmen entscheiden sich daher für Corporate-Social-Responsibility-Marketing: Sie greifen wichtige gesellschaftliche Themen in ihren Kampagnen auf. Nicht immer steckt dahinter ein edles Motiv. Wirtschaftliches Interesse steht häufig über ethischem Antrieb. Doch in einigen Fällen durchschauen Kund*innen diese Irreführung.
Ziel dieser wissenschaftlichen Arbeit ist die Analyse der Auswirkungen von unglaubwürdigem Corporate-Social-Responsibility-Marketing auf die Kaufbereitschaft von Studierenden. Die Untersuchung wird anhand des Unternehmens Nike durchgeführt. Hierfür wird den Proband*innen zunächst ein Corporate-Social-Responsibility-Werbespot von Nike gezeigt. Anschließend wird ihnen ein Skandal präsentiert, der eben diesen Werbespot als reine Marketing-Masche enttarnt. Zwischenzeitlich wird die Kaufbereitschaft der Studierenden mit einem Fragebogen gemessen. Zusätzlich werden die Teilnehmer*innen zu ihren Gedanken und Gefühlen befragt, die Kampagne und Skandal hinterlassen.
Aus dem Experiment ging hervor, dass die Teilnehmer*innen nach der Präsentation des Skandals eine signifikant niedrigere Kaufbereitschaft zeigten. Außerdem wurde ein leicht erhöhtes Interesse an Nikes Tätigkeiten als Sponsor ermittelt. Mehr als die Hälfte der Befragten äußerten zudem ihre Enttäuschung und einen veränderten Blick auf das Unternehmen Nike.
We present a 3D simulation approach utilising the diffuse interface representation of the phase-field method combined with a heat transfer equation to analyse the thermal conductivity in air-filled aluminium foams with complex cellular structures of different porosity. Algorithmic methods are introduced to create synthetic open-cell foam structures and to compute the thermal conductivity by means of phase-field modelling. A material law for the effective thermal conductivity is derived by determining the appropriate exponent depending on the relative density in the system. The results are compared with the thermal conductivity in massive aluminium and in pure air.
Die verstärkte Nachfrage des Marktes nach regelbaren EC-Antrieben mit erhöhten Leistungsdichten fordert das Einsetzen von höherwertigen Elektroblechsorten. Diese weisen durch ihren höheren Siliziumgehalt höhere Härten auf, was zu neue Herausforderungen bei der Montage führt. Das Fügen sogenannter gekerbter Wellen in das Rotorlamellenpaket kann zu Partikelbildung führen, wenn die Härtedifferenz zwischen den beiden Fügepartnern zu gering ausfällt. Dieser Umstand ist zur Einhaltung der steigenden Anforderungen bezüglich technischer Sauberkeit zu vermeiden, da ansonsten kostspielige Reinigungskonzepte in der Montagelinie installiert werden müssen. Für die Montage von Lagern werden die Rotorwellen selektiv induktiv randschichtgehärtet. Hierbei müssen bspw. Lagerstellen eine Mindesthärte erreichen und Kerbzonen unbehandelt bleiben, damit eine entsprechende Umformbarkeit beim Kerben erhalten bleibt sowie der Verschleiß der Kerbwerkzeuge möglichst geringgehalten wird.
Im Rahmen dieser Masterthesis wird die induktive Wärmebehandlung untersucht. Insbesondere wird hier das induktive Hochgeschwindigkeitsvergüten zur Weiterentwicklung der Welle-Nabe-Verbindung im Kerbbereich betrachtet, um bei gleichbleibender Taktzeit die erforderte Härtedifferenz zum Rotorlamellenwerkstoff zu ermöglichen. Hierbei wird der Kerbbereich wie für die Lagermontage induktiv randschichtgehärtet und anschließend bei höheren Temperaturen angelassen (vergütet).
Die Auswertung der Versuchsergebnisse zeigt, dass mit dem vorhandenen Maschinenfuhrpark nur das Anlassen mit Selbstabschreckung die geforderten Härtetoleranzen als Kompromiss zwischen Spanfreiheit beim Fügen und Werkzeugverschleiß ermöglicht. Diese wiederum zeigen aufgrund der ununterbrochene Wärmeleitung eine in Axialrichtung ausgeweiteten Wärmeeinflusszone, die zu unscharfen Härteübergängen im Vergleich zu nach dem Anlassen aktiv gekühlter Rotorwellen führt. Eine höhere Härte in der Kerbzone führt zu einem kleineren Kerbaufwurf unter gleichbleibenden Kerbbedingungen. Der Nachweis einer Prozessfähigkeit für die Härte ist nicht üblich und kann auch aufgrund der hohen Unsicherheit des Härteprüfverfahrens nicht erbracht werden. Das Anlassen verschlechtert nur geringfügig den Rundlauf. Die Einpresskräfte von Rotorlamellenpaketen hängt von der Höhe des Kerbaufwurfs ab und steigt entsprechend mit deren Zunahme. Für eine serientaugliche Umsetzung ist in Abhängigkeit des Anforderungsprofils eine Rücksprache mit der Designabteilung bezüglich axiale Härteübergang und Kerbeindringtiefe notwendig. Für eine dauerhafte Lösung wird die Verwendung eines Mittelfrequenzgenerators für den Anlassprozess empfohlen.
Mit der neuen Abgasnorm Euro VI und den steigenden Kraftstoffpreisen müssen Nutzfahrzeugantriebe eine Reduzierung der CO2-Emission und eine höhere Effizienz vorweisen (Umweltbundesamt, 2015). Um diese Anforderungen erfüllen zu können, wird bei vielen Nutzfahrzeugherstellern intensiv an Systemen zur Rückgewinnung von Abgasenergie, den sogenannten Waste-Heat-Recovery-Systemen, geforscht. Eine Kraftstoffersparnis von rund 5 % wird dabei angestrebt.
Das System basiert auf einem ORC-Prozess. Bei diesem thermodynamischen Kreisprozess wird die Abwärme des Abgases über einen Wärmetauscher geführt, der das organische Arbeitsfluid Ethanol in einem geschlossenen Kreislauf erhitzt. Durch den Dampfdruckaufbau wird eine Turbine angetrieben. Zur Transformation der Enthalpie des Ethanoldampfes in mechanische Energie sind Drehzahlen von bis zu 120000 U/min notwendig, um eine hohe Effizienz des Systems vorweisen zu können. Systemdrücke bis 50 bar und Temperaturen des Ethanoldampfes von maximal 300 °C treten im WHR-System auf und führen zu extremen Beanspruchungen. Eine besondere Herausforderung stellen hierbei die Wellendichtungen, vor allem bei nutzfahrzeugtypischen Lebensdauern, dar. Als interessante Alternative zeigt sich die Zentrifugal-Wellendichtung, um die hohen Dichtungsanforderungen über die geforderten Laufzeiten zuverlässig zu erfüllen.
Durch methodisch stufenweise ablauforientiertes Vorgehen wird die Analyse der Zentrifugal-Wellendichtungen durchgeführt. Hierbei wird zuallererst das Wirkprinzip untersucht. Ein besonderes Augenmerk wird dabei auf die Wärmeeinträge aus der Umgebung und Verwendung unterschiedlicher Sperrfluide gelegt.
Für eine Testdrehzahl von 15000 U/min ergibt sich, bei einer beidseitig glatten Scheibe mit einem Scheibenradius von 8,7 mm, eine maximal abdichtbare Druckdifferenz von 0,04 bar. Im Sperrfluid herrschen hierbei Temperaturen von rund 50 °C. Die Versuche zeigen Korrelationen zu den bekannten theoretischen Ansätzen von Ketola und McGrey. Die maximale Druckdifferenz beträgt in diesem Fall 0,043 bar. Nachdem stationäre Betrachtungen ausreichend untersucht werden, widmet sich diese Arbeit dem Anfahr- und Not-Aus-Verhalten. Die Optimierung des Projekts wird durch abschließende Verbesserungsvorschläge, für die Realisierung höherer Sperrdrücke, erzielt.
Much of the research in the field of audio-based machine learning has focused on recreating human speech via feature extraction and imitation, known as deepfakes. The current state of affairs has prompted a look into other areas, such as the recognition of recording devices, and potentially speakers, by only analysing sound files. Segregation and feature extraction are at the core of this approach.
This research focuses on determining whether a recorded sound can reveal the recording device with which it was captured. Each specific microphone manufacturer and model, among other characteristics and imperfections, can have subtle but compounding effects on the results, whether it be differences in noise, or the recording tempo and sensitivity of the microphone while recording. By studying these slight perturbations, it was found to be possible to distinguish between microphones based on the sounds they recorded.
After the recording, pre-processing, and feature extraction phases we completed, the prepared data was fed into several different machine learning algorithms, with results ranging from 70% to 100% accuracy, showing Multi-Layer Perceptron and Logistic Regression to be the most effective for this type of task.
This was further extended to be able to tell the difference between two microphones of the same make and model. Achieving the identification of identical models of a microphone suggests that the small deviations in their manufacturing process are enough of a factor to uniquely distinguish them and potentially target individuals using them. This however does not take into account any form of compression applied to the sound files, as that may alter or degrade some or most of the distinguishing features that are necessary for this experiment.
Building on top of prior research in the area, such as by Das et al. in in which different acoustic features were explored and assessed on their ability to be used to uniquely fingerprint smartphones, more concrete results along with the methodology by which they were achieved are published in this project’s publicly accessible code repository.
Bud type carbon nanohorns (CNHs) are composed of carbon and have a closed conical tip at one end protruding from an aggregate structure. By employing a simple oxidation process in CO2 atmosphere, it is possible to open the CNH tips which increases their specific surface area by four fold. These tip opened CNHs combine the microporous nature of activated carbons and the crystalline mesoporous character of carbon nanotubes. The results for the high pressure CO2 gas adsorption of tip opened CNHs are reported herein for the first time and are found to be superior to traditional CO2 adsorbents like zeolites. The modified CNHs are also found to be promising materials for lithium ion batteries and the performance is found to be on a par with carbon nanotubes and carbon nanofibers.
Gas adsorption studies of CO2 and N2 in spatially aligned double-walled carbon nanotube arrays
(2013)
Gas adsorption studies (CO2 and N2) over a wide pressure range on vertically, highly aligned dense double-walled carbon nanotube arrays of high purity and high specific surface area are reported. At high pressures, the adsorption capacity of these materials was found to be comparable to those of metal organic frameworks and mesoporous molecular sieves. These highly aligned CNT arrays were chemically modified by treating with oxygen plasma and structurally modified by decreasing the diameter of individual carbon nanotubes. Oxygen plasma treatment led to grafting of a large number of C–O functional groups onto the CNT surface, which further increased the gas adsorption capacity. It was found that gas adsorption is dependent on tube diameter and increases with decrease of the individual CNT diameter in the CNT bundles. As results of our studies we have found that at lower pressure regimes, plasma functionalized carbon nanotubes exhibit better adsorption characteristics whereas at higher pressures, lower diameter carbon nanotube structures exhibited better gas adsorption characteristics.
Many different methods, such as screen printing, gravure, flexography, inkjet etc., have been employed to print electronic devices. Depending on the type and performance of the devices, processing is done at low or high temperature using precursor- or particle-based inks. As a result of the processing details, devices can be fabricated on flexible or non-flexible substrates, depending on their temperature stability. Furthermore, in order to reduce the operating voltage, printed devices rely on high-capacitance electrolytes rather than on dielectrics. The printing resolution and speed are two of the major challenging parameters for printed electronics. High-resolution printing produces small-size printed devices and high-integration densities with minimum materials consumption. However, most printing methods have resolutions between 20 and 50 μm. Printing resolutions close to 1 μm have also been achieved with optimized process conditions and better printing technology.
The final physical dimensions of the devices pose severe limitations on their performance. For example, the channel lengths being of this dimension affect the operating frequency of the thin-film transistors (TFTs), which is inversely proportional to the square of channel length. Consequently, short channels are favorable not only for high-frequency applications but also for high-density integration. The need to reduce this dimension to substantially smaller sizes than those possible with today’s printers can be fulfilled either by developing alternative printing or stamping techniques, or alternative transistor geometries. The development of a polymer pen lithography technique allows scaling up parallel printing of a large number of devices in one step, including the successive printing of different materials. The introduction of an alternative transistor geometry, namely the vertical Field Effect Transistor (vFET), is based on the idea to use the film thickness as the channel length, instead of the lateral dimensions of the printed structure, thus reducing the channel length by orders of magnitude. The improvements in printing technologies and the possibilities offered by nanotechnological approaches can result in unprecedented opportunities for the Internet of Things (IoT) and many other applications. The vision of printing functional materials, and not only colors as in conventional paper printing, is attractive to many researchers and industries because of the added opportunities when using flexible substrates such as polymers and textiles. Additionally, the reduction of costs opens new markets. The range of processing techniques covers laterally-structured and large-area printing technologies, thermal, laser and UV-annealing, as well as bonding techniques, etc. Materials, such as conducting, semiconducting, dielectric and sensing materials, rigid and flexible substrates, protective coating, organic, inorganic and polymeric substances, energy conversion and energy storage materials constitute an enormous challenge in their integration into complex devices.
The suffix-free-prefix-free hash function construction and its indifferentiability security analysis
(2012)
In this paper, we observe that in the seminal work on indifferentiability analysis of iterated hash functions by Coron et al. and in subsequent works, the initial value (IV) of hash functions is fixed. In addition, these indifferentiability results do not depend on the Merkle–Damgård (MD) strengthening in the padding functionality of the hash functions. We propose a generic n-bit-iterated hash function framework based on an n-bit compression function called suffix-free-prefix-free (SFPF) that works for arbitrary IVs and does not possess MD strengthening. We formally prove that SFPF is indifferentiable from a random oracle (RO) when the compression function is viewed as a fixed input-length random oracle (FIL-RO). We show that some hash function constructions proposed in the literature fit in the SFPF framework while others that do not fit in this framework are not indifferentiable from a RO. We also show that the SFPF hash function framework with the provision of MD strengthening generalizes any n-bit-iterated hash function based on an n-bit compression function and with an n-bit chaining value that is proven indifferentiable from a RO.
Um Simulationen schnell und kostengünstig sowie ergebnisträchtig durchzuführen, bedarf es einer sorgfältigen Vorbereitung. Der Artikel befaßt sich mit dem automatischen Ablauf einer Simulationstudie zum Materilafluß und erläutert die im Ablauf notwendigen Beiträge der Anwender. In den Einzelheiten wird über die automatische Vorgehensweise und Anwendung der Standard-Simulationsmodelle (SSM) sowie spezieller Simulationsmodule (SimDBC) berichtet. Entscheidend für eine breitere Anwendung von Simulationswerkzeugen ist die einfache Handhabung und leicht verständliche Definition der zu untersuchenden Szenarien.
This paper presents a system that uses a multi-stage AI analysis method for determining the condition and status of bicycle paths using machine learning methods. The approach for analyzing bicycle paths includes three stages of analysis: detection of the road surface, investigation of the condition of the bicycle paths, and identification of substrate characteristics. In this study, we focus on the first stage of the analysis. This approach employs a low-threshold data collection method using smartphone-generated video data for image recognition, in order to automatically capture and classify surface condition and status.
For the analysis convolutional neural networks (CNN) are employed. CNNs have proven to be effective in image recognition tasks and are particularly well-suited for analyzing the surface condition of bicycle paths, as they can identify patterns and features in images. By training the CNN on a large dataset of images with known surface conditions, the network can learn to identify common features and patterns and reliably classify them.
The results of the analysis are then displayed on digital maps and can be utilized in areas such as bicycle logistics, route planning, and maintenance. This can improve safety and comfort for cyclists while promoting cycling as a mode of transportation. It can also assist authorities in maintaining and optimizing bicycle paths, leading to more sustainable and efficient transportation system.
Since their dawning, space communications have been among the strongest driving applications for the development of error correcting codes. Indeed, space-to-Earth telemetry (TM) links have extensively exploited advanced coding schemes, from convolutional codes to Reed-Solomon codes (also in concatenated form) and, more recently, from turbo codes to low-density parity-check (LDPC) codes. The efficiency of these schemes has been extensively proved in several papers and reports. The situation is a bit different for Earth-to-space telecommand (TC) links. Space TCs must reliably convey control information as well as software patches from Earth control centers to scientific payload instruments and engineering equipment onboard (O/B) spacecraft. The success of a mission may be compromised because of an error corrupting a TC message: a detected error causing no execution or, even worse, an undetected error causing a wrong execution. This imposes strict constraints on the maximum acceptable detected and undetected error rates.
NEXCODE is a project promoted by the European Space Agency aimed at research design development and demonstration of a receiver chain for telecomm and links in space missions including the presence of new short low-density parity-check codes for error correction. These codes have excellent performance from the error rate viewpoint but also put new challenges as regards synchronization issues and implementation. In this paper after a short review of the results obtained through numerical simulations we present an overview of the breadboard designed for practical testing and the test-plan proposed for the verification of the breadboard and the validation of the new codes and novel synchronization techniques under relevant operation conditions.
Im Rahmen dieser Masterarbeit soll ein Radträger für ein Leichtbaufahrzeug entwickelt werden. Dieser soll ein niedriges Gewicht sowie eine hohe Steifigkeit aufweisen und fertigbar sein.
Dabei wird über einen iterativen Prozess aus Simulation, Topologieoptimierung und Neukonstruktion ein neues Radträgerdesign entwickelt.
Zu Beginn der Arbeit wird auf die wissenschaftlichen Grundlagen eingegangen. Dabei spielen vor allem das Thema Leichtbau sowie die finite Elemente Methode eine Rolle. Es wird auf Prinzipien der Konstruktion eingegangen, um das Bauteil fertigungsgerecht und auch effizient zu gestalten.
Im nächsten Kapitel wird der aktuelle Stand der Technik genauer untersucht. Hierbei wird der Entwicklungsprozess der aktuellen Radträger-Varianten untersucht und diese mittels FEM nachgerechnet. Zuvor werden noch die für die Simulation benötigten wirkenden Kräfte berechnet und Plausibilitätstests durchgeführt, bei denen Computersimulationen mit realen Messwerten auf deren Richtigkeit überprüft werden.
In den letzten Kapiteln geht es um die Entwicklung des Radträgers. Hier werden einige Konzepte entwickelt und mittels FEM-Simulationen getestet. Durch den Einsatz von Topologieoptimierungen wird versucht, das Gewicht des Radträgers bei gleichbleibender Steifigkeit zu senken.
Durch den digitalen Wandel, sowie durch die an Benutzerfreundlichkeit und Leistung zunehmenden technischen Geräte im Endbenutzer-Bereich beginnt die Bedeutung von Augmented-Reality Applikationen zu wachsen. Daher ist das Ziel dieser Arbeit die Entwicklung einer Engine auf iOS Basis, zur Dastellung von Augmented-Reality Inhalten. Die Engine wurde nach dem Vorbild von Komponenten-basierten Game Engines entworfen, da diese beinahe identische Anforderungen besitzen. Die, im Rahmen dieser Arbeit erstellte Engine wurde mit Unterstützung der 5d lab Gmb entwickelt. Durch die Verwendung des, nach Erfahrungswerten, schnellsten Mobile Augmented Reality SDK und einer gelungenen Engine-Architektur konnte ein Produkt entwickelt werden, dass mit bestehenden Applikationen konkurrenzfähig ist.
The three lines of defense model (TLoD) aims to provide a simple and effective way to improve coordination and enhance communications on risk management and control by clarifying the essential roles and duties of different governance functions. Without effective coordination of these governance functions, work can be duplicated or key risks may be missed or misjudged. To address these challenges, professional standards recommend that the chief audit executive (CAE) coordinates activities with other internal and external governance stakeholders (assurance providers). We consider survey responses from 415 CAEs from Austria, Germany, and Switzerland to analyze determinants that help to implement the TLoD without any challenges and to explore the extent of (coordination) challenges between the internal audit function and the respective governance stakeholders. Our results show a great variance in the extent of coordination challenges dependent on different determinants and the respective governance stakeholder.
Crowdinvesting als alternative Unternehmensfinanzierung - Grundlagen und Marktdaten in Deutschland
(2015)
Interne Revision: Anforderungen an die Wirksamkeit – ein Vergleich von IDW EPS 983 und MaRisk
(2017)
The invention relates to the field of transporting flat substrates such as silicon substrates. In particular, the invention relates to particularly protective and continuous transport of such substrates. The method according to the invention is used to transport a vertically aligned flat substrate (1) comprising two flat sides in a transport direction inside a transport channel (2) that is at least partially filled with a liquid medium (F), wherein said liquid medium (F) flows against at least one of the flat sides of the substrate (1) and has a supporting component, which lifts the sum of the weight and buoyancy force of the substrate (1), and an advancing component, which is directed in the transport direction, so that the substrate (1) is supported and transported without mechanical aids. The device according to the invention comprises a transport channel (2) for accommodating a liquid medium (F) and a substrate (1) to be guided in vertical alignment within said medium (F), wherein the transport channel (2) has inflow openings (5) in the walls (3, 4).
Die Erfindung betrifft das Gebiet des Transports flacher Substrate wie beispielsweise Siliziumsubstrate. Insbesondere betrifft die Erfindung den besonders schonenden und kontinuierlichen Transport solcher Substrate. Das erfindungsgemäße Verfahren dient dem Transport eines vertikal ausgerichteten flachen Substrats (1) in eine Transportrichtung innerhalb eines mit einem flüssigen Medium (F) gefüllten Transportkanals (2), wobei das flüssige Medium (F) gegen mindestens eine der Flachseiten des Substrats (1) strömt und eine die Summe aus Gewichts- und Auftriebskraft des Substrats (1) aufhebende Tragekomponente, sowie eine in Transportrichtung gerichtete Vorschubkomponente aufweist, so dass das Substrat (1) ohne mechanische Hilfsmittel getragen und transportiert wird. Die erfindungsgemäße Vorrichtung umfasst einen Transportkanal (2) zur Aufnahme eines flüssiges Mediums (F) sowie eines innerhalb dieses Mediums (F) in vertikaler Ausrichtung zu führenden Substrats (1), wobei der Transportkanal (2) in seinem Wandbereich (3, 4) Einströmöffnungen (5) aufweist.
Die Erfindung betrifft das Gebiet des Transports flacher Substrate wie beispielsweise Siliziumsubstrate. Insbesondere betrifft die Erfindung den besonders schonenden und kontinuierlichen Transport solcher Substrate. Das erfindungsgemäße Verfahren dient dem Transport eines vertikal ausgerichteten flachen Substrats (1) in eine Transportrichtung innerhalb eines mit einem flüssigen Medium (F) gefüllten Transportkanals (2), wobei das flüssige Medium (F) gegen mindestens eine der Flachseiten des Substrats (1) strömt und eine die Summe aus Gewichts- und Auftriebskraft des Substrats (1) aufhebende Tragekomponente, sowie eine in Transportrichtung gerichtete Vorschubkomponente aufweist, so dass das Substrat (1) ohne mechanische Hilfsmittel getragen und transportiert wird. Die erfindungsgemäße Vorrichtung umfasst einen Transportkanal (2) zur Aufnahme eines flüssiges Mediums (F) sowie eines innerhalb dieses Mediums (F) in vertikaler Ausrichtung zu führenden Substrats (1), wobei der Transportkanal (2) in seinem Wandbereich (3, 4) Einströmöffnungen (5) aufweist.
A two-dimensional single-phase model is developed for the steady-state and transient analysis of polymer electrolyte membrane fuel cells (PEMFC). Based on diluted and concentrated solution theories, viscous flow is introduced into a phenomenological multi-component modeling framework in the membrane. Characteristic variables related to the water uptake are discussed. A Butler–Volmer formulation of the current-overpotential relationship is developed based on an elementary mechanism of electrochemical oxygen reduction. Validated by using published V–I experiments, the model is then used to analyze the effects of operating conditions on current output and water management, especially net water transport coefficient along the channel. For a power PEMFC, the long-channel configuration is helpful for internal humidification and anode water removal, operating in counterflow mode with proper gas flow rate and humidity. In time domain, a typical transient process with closed anode is also investigated.
The state-of-the-art electrochemical impedance spectroscopy (EIS) calculations have not yet started from fully multi-dimensional modeling. For a polymer electrolyte membrane fuel cell (PEMFC) with long flow channel, the impedance plot shows a multi-arc characteristic and some impedance arcs could merge. By using a step excitation/Fourier transform algorithm, an EIS simulation is implemented for the first time based on the full 2D PEMFC model presented in the first part of this work. All the dominant transient behaviors are able to be captured. A novel methodology called ‘configuration of system dynamics’, which is suitable for any electrochemical system, is then developed to resolve the physical meaning of the impedance spectra. In addition to the high-frequency arc due to charge transfer, the Nyquist plots contain additional medium/low-frequency arcs due to mass transfer in the diffusion layers and along the channel, as well as a low-frequency arc resulting from water transport in the membrane. In some case, the impedance spectra appear partly inductive due to water transport, which demonstrates the complexity of the water management of PEMFCs and the necessity of physics-based calculations.
Erarbeitung von zwei unterschiedlichen Marken- und Werbekonzepten zur Ermittlung der Image- und Gestaltungswirkung. Eine einzigartige Werbemittelgestaltung, abgestimmt auf das Markenimage, die Zielgruppe und den Produktnutzen, ist für die Wirkung auf den Konsumierenden und damit den wirtschaftlichen Erfolg von hoher Bedeutung. Im Rahmen der vorliegenden Bachelorarbeit wurde eine qualitative Untersuchung der Image- und Gestaltungswirkung auf den Konsumierenden durchgeführt. Theoretische Ansätze zum Thema Marken und Werbung in Verbindung mit psychologischen Erklärungen bilden dafür eine fundierte Basis. Als Untersuchungsobjekt fungieren zwei eigen kreierte Werbemittel, welche auf Basis theoretischer Grundlagen für das identische fiktive Produkt erstellt wurden. Bei dem Produkt handelt es sich um einen Energy-Drink, welcher eine junge dynamische Zielgruppe ansprechen soll. Dabei zeigen die teilweise gegensätzlich gestalteten Plakate auf, welche Techniken im Hinblick auf das Produkt sowie die vorher definierte Zielgruppe funktionieren und welche nicht.
Photovoltaic-heat pump (PV-HP) combinations with battery and energy management systems are becoming increasingly popular due to their ability to increase the autarchy and utilization of self-generated PV electricity. This trend is driven by the ongoing electrification of the heating sector and the growing disparity between growing electricity costs and reducing feed-in tariffs in Germany. Smart control strategies can be employed to control and optimize the heat pump operation to achieve higher self-consumption of PV electricity. This work presents the evaluation results of a smart-grid ready controlled PV-HP-battery system in a single-family household in Germany, using 1-minute-high-resolution field measurement data. Within 12 months evaluation period, a self-consumption of 43% was determined. The solar fraction of the HP amounts to 36%, enabled also due to higher set temperatures for space heating and domestic hot water production. Accordingly, the SPF decreases by 4.0% the space heating and by 5.7% in the domestic hot water mode. The combined seasonal performance factor for the heat pump system increases from 4.2 to 6.7, when only considering the electricity taken from the grid and disregarding the locally generated electricity supplied from photovoltaic and battery units.
Synthesizing voice with the help of machine learning techniques has made rapid progress over the last years [1]. Given the current increase in using conferencing tools for online teaching, we question just how easy (i.e. needed data, hardware, skill set) it would be to create a convincing voice fake. We analyse how much training data a participant (e.g. a student) would actually need to fake another participants voice (e.g. a professor). We provide an analysis of the existing state of the art in creating voice deep fakes and align the identified as well as our own optimization techniques in the context of two different voice data sets. A user study with more than 100 participants shows how difficult it is to identify real and fake voice (on avg. only 37 percent can recognize a professor’s fake voice). From a longer-term societal perspective such voice deep fakes may lead to a disbelief by default.
Synthesizing voice with the help of machine learning techniques has made rapid progress over the last years. Given the current increase in using conferencing tools for online teaching, we question just how easy (i.e. needed data, hardware, skill set) it would be to create a convincing voice fake. We analyse how much training data a participant (e.g. a student) would actually need to fake another participants voice (e.g. a professor). We provide an analysis of the existing state of the art in creating voice deep fakes and align the identified as well as our own optimization techniques in the context of two different voice data sets. A user study with more than 100 participants shows how difficult it is to identify real and fake voice (on avg. only 37% can recognize a professor’s fake voice). From a longer-term societal perspective such voice deep fakes may lead to a disbelief by default.
Background: This paper presents a novel approach for a hand prosthesis consisting of a flexible, anthropomorphic, 3D-printed replacement hand combined with a commercially available motorized orthosis that allows gripping.
Methods: A 3D light scanner was used to produce a personalized replacement hand. The wrist of the replacement hand was printed of rigid material; the rest of the hand was printed of flexible material. A standard arm liner was used to enable the user’s arm stump to be connected to the replacement hand. With computer-aided design, two different concepts were developed for the scanned hand model: In the first concept, the replacement hand was attached to the arm liner with a screw. The second concept involved attaching with a commercially available fastening system; furthermore, a skeleton was designed that was located within the flexible part of the replacement hand.
Results: 3D-multi-material printing of the two different hands was unproblematic and inexpensive. The printed hands had approximately the weight of the real hand. When testing the replacement hands with the orthosis it was possible to prove a convincing everyday functionality. For example, it was possible to grip and lift a 1-L water bottle. In addition, a pen could be held, making writing possible.
Conclusions: This first proof-of-concept study encourages further testing with users.
Total Cost of Ownership (TCO) is a key tool to have a complete understanding of the costs associated with an investment, as it allows to analyze not only the initial acquisition costs, but also the long-term costs related to operation, maintenance, depreciation, and other factors. In the context of the cement industry, TCO is especially important due to the complexity of the production processes and the wide variety of components and machinery involved in the process.
For this reason, a TCO analysis for the cement industry has been conducted in this study, with the objective of showing the different components of the cost of production. This analysis will allow the reader to gain knowledge about these costs, in the industrial model will be to make informed decisions on the adoption of technologies and practices that will allow them to reduce costs in the long run and improve their operational efficiency.
In particular, this study pursues to give visibility to technologies and practices that enable the reduction of carbon emissions in cement production, thus contributing to the sustainability of industry and the protection of the environment. By being at the forefront of sustainability issues, the cement industry can contribute to the achievement of environmentally friendly technologies and enable the development of people and industry.
The Oxyfuel technology has been selected as a carbon capture solution for the cement industry due to its practical application, low costs, and practical adaptation to non-capture processes. The adoption of this technology allows for a significant reduction in CO2 emissions, which is a crucial factor in achieving sustainability in the cement manufacturing process.
Carbon capture storage technologies represent a high investment, although these technologies increase the cost of production, the application of Oxyfuel technology is one of the most economically viable as the cheapest technology per capture according to the comparison. However, this price increase is a technical advantage as the carbon capture efficiency of this technology reaches 90%. This level of efficiency leads to a decrease in taxes for the generation of CO2 emissions, making the cement manufacturing process sustainable.
Schluckspecht project
(2022)
This work provides a series of methane adsorption isotherms and breakthrough curves on one 5A zeolite and one activated carbon. Breakthrough curves of CH4 were obtained from dynamic column measurements at different temperature and pressure conditions for concentrations of 4.4 – 17.3 mol.‐% in H2/CH4 mixtures. A simple model was developed to simulate the curves using measured and calculated data inputs. The results show that the model predictions agree very well with the experiments.
The separation of nitrogen and methane from hydrogen-rich mixtures is systematically investigated on a recently developed binder-free zeolite 5A. For this adsorbent, the present work provides a series of experimental data on adsorption isotherms and breakthrough curves of nitrogen and methane, as well as their mixtures in hydrogen. Isotherms were measured at temperatures of 283–313 K and pressures of up to 1.0 MPa. Breakthrough curves of CH4, N2, and CH4/N2 in H2 were obtained at temperatures of 300–305 K and pressures ranging from 0.1 to 6.05 MPa with different feed concentrations. An LDF-based model was developed to predict breakthrough curves using measured and calculated data as inputs. The number of parameters and the use of correlations were restricted to focus on the importance of measured values. For the given assumptions, the results show that the model predictions agree satisfactorily with the experiments under the different operating conditions applied.
Regarding the importance of adsorptive removal of carbon monoxide from hydrogen-rich mixtures for novel applications (e.g. fuel cells), this work provides a series of experimental data on adsorption isotherms and breakthrough curves of carbon monoxide. Three recently developed 5A zeolites and one commercial activated carbon were used as adsorbents. Isotherms were measured gravimetrically at temperatures of 278–313 K and pressures up to 0.85 MPa. Breakthrough curves of CO were obtained from dynamic column measurements at temperatures of 298–301 K, pressures ranging from 0.1 MPa to ca. 6 MPa and concentrations of CO in H2/CO mixtures of 5–17.5 mol%. A simple mathematical model was developed to simulate breakthrough curves on adsorbent beds using measured and calculated data as inputs. The number of parameters and the use of correlations to evaluate them were restricted in order to focus the importance of measured values. For the given assumptions and simplifications, the results show that the model predictions agree satisfactorily with the experimental data at the different operating conditions applied.
As a basis for the evaluation of hydrogen storage by physisorption, adsorption isotherms of H2 were experimentally determined for several porous materials at 77 K and 298 K at pressures up to 15 MPa. Activated carbons and MOFs were studied as the most promising materials for this purpose. A noble focus was given on how to determine whether a material is feasible for hydrogen storage or not, dealing with an assessment method and the pitfalls and problems of determining the viability. For a quantitative evaluation of the feasibility of sorptive hydrogen storage in a general analysis, it is suggested to compare the stored amount in a theoretical tank filled with adsorbents to the amount of hydrogen stored in the same tank without adsorbents. According to our results, an “ideal” sorbent for hydrogen storage at 77 K is calculated to exhibit a specific surface area of >2580 m2 g−1 and a micropore volume of >1.58 cm3 g−1.
Im Rahmen einer Master Thesis wurde ausgehend von einem vorhandenen System On Chip Design, welches eingehende EKG-Datensignale verarbeitet, das bestehende System so erweitert dass es komplett über den standardisierten SPI-Bus steuerbar und auslesbar ist.
Im ASIC Design Center der Hochschule Offenburg wird ein Design Kit für die UMC 0.18μm Faraday Technologie aufbereitet. Dabei werden alle benötigten Dateien, welche für einen zunächst rein digitalen Chipentwurf unter Verwendung der Synopsys, Cadence und Mentor Tools benötigt werden, für den UMC 0.18μm Prozess zusammengestellt.
Compliance Due Diligence
(2017)
Nahezu jedes Unternehmen hat heute auf seiner Homepage einen eigenen Bereich integriert, in welchem Compliance- und Integrity-Maßnahmen vorgestellt werden. Auslöser hierfür dürften wohl nicht nur die immer strengeren Gesetze sein, sondern vielmehr Unternehmensskandale, welche in den Unternehmen für Unruhe sorgten. Man denke hierbei beispielsweise an die Korruptionsskandale bei MAN oder Siemens sowie aktuell der Volkswagen Abgas-Skandal. Die Folgen können weitreichend sein. Schadensersatzzahlungen, Auftragsverluste oder auch große Image-Schäden sind die Folgen. Zu erkennen ist ebenfalls, dass auch immer mehr mittelständische Unternehmen das Thema Compliance für sich entdecken. Es ist also keinesfalls davon auszugehen, dass nur die großen Unternehmen hohen Haftungsrisiken ausgesetzt sind. Dennoch sind konkrete Compliance-Programme in diesen meist eher vorhanden und konkret ausgestaltet.
Ziel der folgenden Bachelorarbeit ist es, eine Steuerung für einen Motorenprüfstand zu entwickeln. Dieser wurde von Aaron Maier geplant und konstruiert. Die Steuerung soll es ermöglichen, die Motoren des Prüfstands sowohl manuell als auch automatisiert anzusteuern. Dabei sollen die Parameter Drehmoment, Drehzahl, Spannung, Strom sowie die Temperatur der Motoren automatisiert, oder auf Knopfdruck erfasst und abgelegt werden. Die Arbeit umfasst die Auswahl der benötigten Hardwarekomponenten, das Verbauen dieser Komponenten in einem Bedienpult, die elektrische Verschaltung dieser Komponenten, die Programmierung des Microkontrollers und das Erstellen einer Dokumentation.
Die touristische Entwicklung in den deutschen Urlaubsorten gestaltet sich derzeit in der Regel sehr positiv. Dies ist einerseits sehr erfreulich und sollte Anlass für das Marketing geben, diese Situation zu verfestigen und zu verstärken; andererseits zeigt eine nähere Betrachtung, dass sich die Besucherströme in erster Linie auf die Hauptsaisonzeiten der jeweiligen Urlaubsgebiete konzentrieren. Für viele Bäderorte, vor allem etwa auch die der Ost- und Nordseeküste, sind dies die Ferienzeiten im Sommer. So verzeichnen viele Hotels und Restaurants bis zu 70 % ihrer Jahreseinnahmen in dieser nur dreimonatigen Periode. Das Problem besteht nun in den übrigen Jahreszeiten vor allem darin, dass bei geringem Umsatz trotzdem Personal und Einrichtungen vorgehalten werden müssen. Auch die vorhandenen gemeindlichen und privaten Infrastrukturen werden in den Nebensaisonzeiten nicht genügend ausgelastet. Läden und Geschäfte leiden zum Teil unter der geringen Gästezahl. Manche Urlaubsorte wirken, so vor allem im Winter, oft in diesen Zeiten wie ausgestorben. Entwicklungsbedarf entsteht nun darin, auch Angebote zu schaffen, die einen Ferienaufenthalt im Herbst, Winter und Frühjahr attraktiver machen. Vor diesem Hintergrund ist es das Ziel der folgenden Ausführungen, entsprechende innovative Lösungsansätze aufzuzeigen.
Die vorliegenden Arbeit befasst sich mit dem datengetriebenen Targeting im Social-Media Advertising. Sie gibt einen Einblick in die verschiedenen Möglichkeiten der datengetriebenen Zielgruppenansprache, welche die sozialen Netzwerke für werbetreibenden Unternehmen zur Verfügung stellen. Zu Beginn werden die Grundlagen des Datenmanagements dargestellt und anschließend die wesentlichen Targeting-Techniken sowie die technischen und juristischen Grenzen präsentiert. Dabei wird auf die Relevanz der Zielgruppenbestimmung eingegangen. Im Weiteren werden die Varianten des Social-Media-Targeting am Beispiel von Facebook ausgearbeitet. Am Ende wird ein Überblick über die Plattformen Facebook, Instagram, Twitter, LinkedIn, Pinterest und YouTube entwickelt.
Datengetriebenes Targeting
(2020)
Ein Sachcomic von Schlogger:
- Warum streiten wir?
- Welche gesellschaftlichen und psychologischen Probleme erschweren moderne Beziehungen?
- Wie streiten wir?
- Warum lohnt es sich Streiten zu lernen?
- Was ist Kommunikation und was kann dabei schief laufen?
- Wie streiten wir konstruktiver?
Diese Fragen versucht "STREIT[SAM]"anhand vieler grafischer Beispiele und Theorien wie z.B."Das Vier-Seiten-Modell" von Schulz von Thun, den "Axiomen zur Kommunikationspsychologie"
von Paul Watzlawick oder der Gewaltfreien Kommunikation nach Rosenberg zu beantworten.