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The iSign project started in 2000 as a web-based laboratory setting for students of electrical engineering. In the meantime it has broadened into a heterogeneous learning environment offering learning material, adaptive user settings and access to a simulation tool. All these offerings can be accessed via web and wireless by different clients, such as PCs, PDAs and mobile phones. User adaptive systems offer unique and personalised environment for every learner and therefore are a very important aspect of modern e-learning systems. The iSign project aims to personalise the content structure based on the learner's behaviour, content pattern, policies, and system environment. The second aspect of the recent research and development within this project is the generation of suitable content and presentation for different clients. This generation is based additionally on the user preferences in order to obtain the desirable presentation for a given device. New, valuable features are added to the mobile application, empowering the user not only to control the simulation process with his mobile device but also to input data, view the simulation's output and evaluate the results. Experiences with students have helped to improve functionality and look-and-feel whilst using the iSign system. Our goal is to provide unconstrained, continuous and personalised access to the laboratory settings and learning material everywhere and at anytime with different devices.
The Division Industrial Chemistry of the Swiss Chemical Society organizes periodically a two-day event for the post-graduate education of its members. This event is known as the Freiburger Symposium. This year it focussed on sustainable chemical production. The twelve talks covered the following aspects: ethical needs for sustainability standards, the required, attained, and yet to be attained sustainability goals in chemical industry. Diverse case studies showed the highly developed awareness about the sustainability issue within the chemical community.
A platform of an electronic capsule is being developed for multi-task medical assistant application. It includes a near field telemetry unit for bidirectional communication system of 115 KHz low carrier frequency for inductive data transmission suited for human body energy transfer. The system triggers an actuator for drug delivery in various time and release forms via wireless external control, it has the ability to record temperature, measure pH of the body (additional sensors), and retrieve data to the outside. It consists of a 32bit processor, memory, external peripheries, and detection facility. The complete system is designed to fit small-size mass medical application with low power consumption, size of 7x25mm. The system is designed, simulated and emulated on FPGA. A final layout of the complete chip design is still under progress.
This paper shows the results of the evaluation of two sets of mobile web design guidelines concerning mobile learning. The first set of guidelines is concerned with the usage of text on mobile device screens. The second set is concerned with the usage of images on mobile devices. The evaluation is performed by eye tracking (objective) as well as questionnaires and interviews (subjective) respectively.
This paper describes the magmaOffenburg 3D simulation team trying to qualify for RoboCup 2009. It focuses on two distinctive features of the team: decisions making using extended behavior networks and its software architecture and implementation in Java to open the simulation for the Java community.
Innovative technologies and concepts will emerge as we move towards a more dynamic, service-based, market-driven infrastructure, where energy efficiency and savings can be facilitated by interactive distribution networks. A new generation of fully interactive Information and Communication Technologies (ICT) infrastructure has to be developed to support the optimal exploitation of the changing, complex business processes and to enable the efficient functioning of the deregulated energy market for the benefit of citizens and businesses. The architecture of such distributed system landscapes must be designed and validated, standards need to be created and widely supported, and comprehensive, reliable IT applications will need to be implemented. The collaboration between a smart house and a smart grid is a promising approach which, with the help of ICT can fully unleash the capabilities of the smart electricity network.
The developed solution enables the presentation of animations and 3D virtual reality (VR) on mobile devices and is well suited for mobile learning, thus creating new possibilities in the area of e-learning worldwide. Difficult relations in physics as well as intricate experiments in optics can be visualised on mobile devices without need for a personal computer.
The idea of this game is to use a flashcard system to create a short story in a foreign language. The story is developed by a group of people by exchanging sentences via a flashcard system. This way, people can learn from each other without fear of making mistakes because the group members are anonymous.
Flashcards are a well known and proven method to learn and memorise. Such a way of learning is perfectly suited for “learning on the way,” but carrying all the flashcards could be awkward. In this scenario, a mobile device (mobile phone) is an adequate solution. The new mobile device operating system Android from Google allows for writing multimedia-enriched applications.
“Today’s network landscape consists of quite different network technologies, wide range of end-devices with large scale of capabilities and power, and immense quantity of information and data represented in different formats” [9]. A lot of efforts are being done in order to establish open, scalable and seamless integration of various technologies and content presentation for different devices including mobile considering individual situation of the end user. This is very difficult because various kinds of devices used by different users or in different times/parallel by the same user which is not predictable and have to be recognized by the system in order to know device capabilities. Not only the devices but also Content and User Interfaces are big issues because they could include different kinds of data format like text, image, audio, video, 3D Virtual Reality data and upcoming other formats. Language Learning Game (LLG) is such an example of a device independent application where different kinds of devices and data formats, as a content of a flashcard is used for a collaborative learning. The idea of this game is to create a short story in a foreign language by using mobile devices. The story is developed by a group of participants by exchanging sentences/data via a flashcard system. This way the participants can learn from each other by knowledge sharing without fear of making mistakes because the group members are anonymous. Moreover they do not need a constant support from a teacher.
Die Einhaltung der innerhalb der Designphase festgelegten Architektur eines Softwareprojektes muss w ̈ahrend der Entwicklungsphase sichergestellt werden. Dieses Papier beschreibt eine Erweiterung des Eclipse-Plugins JDepend4Eclipse, die die Verwaltung von Regels ̈atzen erlaubt und die Pr ̈ufung auf in einem Projekt vorhandene, unerlaubte Abh ̈angigkeiten auf Knopfdruck innerhalb der Entwicklungsumgebung vornimmt. Die Erweiterung des Plugins wird bereits erfolgreich in internen Projekten der Hochschule Offenburg eingesetzt und soll demn ̈achst ̈offentlich verf ̈ugbar sein.
This paper describes the magmaOffenburg 3D simulation team trying to qualify for RoboCup 2010. While last year’s TDP focused on decisions making using extended behavior networks and on its software architecture and implementation in this year we describe the tool set that was created for RoboCup 3D. It contians a GUI for agent- and world state visualization, for evaluation of localization algorithms and benchmarks in general, a visual editor for Extended Behavior Networks creation and debugging, a live movement tool to interact with the joints and finally a tool for editing behavior motor files.
Vergleich der hämodynamischen Reaktion auf VV-Delay Änderungen bei Sinusrhythmus und Vorhofflimmern
(2010)
Termination of atrial flutter (AFL) is not possible in all AFL patients (P) with transesophageal left atrial pacing (TLAP) with undirected electrical pacing field (EPF) and high atrial pacing threshold. Purpose of the study was to evaluate bipo-lar transesophageal left atrial electrocardiography (TLAE) and TLAP with directed EPF for evaluation and termination of AFL with and without simultaneous transesophageal echocardiography (TEE).
Methods: AFL P were analysed using either a TO electrode with one cylindrical (CE) and three or seven hemispherical electrodes (HE) or TEE electrode with four HE (Osypka, Rheinfelden, Germany). Burst TLAP cycle length was between 200msand 50ms.
Results: AFL cycle length was 233±30 ms with mean ventricular cycle length of 540±149 ms. AFL could be terminated by rapid bipolar TLAP with directed EPF using HE-HE and CE-HE with induction of atrial fibrillation (AF), induction of AF and spontaneous conversion to sinus rhythm and direct conversion to sinus rhythm. Directed EPF was simulated with finite element method.
Conclusions: AFL can be evaluated by bipolar TLAE. AFL can be terminated with rapid TLAP with directed EPF with and without simultaneous TEE. Bipolar TLAE with rapid TLAP is a safe, simple and useful method for evaluation and termination of AFL.
Cardiac resynchronisation therapy (CRT) with biventricular pacing (BV) is an established therapy for heart failure (HF) patients with interventricular conduction delay (IVCD). The aim of the study was to evaluate transesophageal IVCD and left ventricular (LV) pacing with directed electrical pacing field (EPF) in HF patients.
Methods: HF patients were analysed with bipolar transesophageal LV electrocardiogram recording and LV pacing with constant voltage stimulus output, 4 ms stimulus duration, distal cylindrical electrode (CE) and seven 6 mm hemispherical electrodes (HE) with 15 mm electrode distance (TO, Dr. Osypka, Rheinfelden, Germany).
Results: LV electrocardiogram recording with HE-HE and CE-HE evaluated a mean IVCD of 79.9 ± 36.7 ms. Directed EPF with CE-HE and HE-HE allowed LV VAT (n=12) and LV D00 pacing (n=5) with a mean effective capture output of 97.35 ± 6.64 V. In 15 responders with IVCD of 87 ± 33 ms arterial pulse pressure (PP) increased from 65 ± 24 mmHg to 79 ± 27 mmHg (p < 0.001). EPF was simulated with finite element method.
Conclusions: Transesophageal LV electrocardiography and directed EPF pacing with CE and HE allowed the evaluation of IVCD and PP to select patients for BV pacing.
This paper describes the magmaOffenburg 3D simulation team trying to qualify for RoboCup 2011. While last year’s TDP focused on the tool set created for 3D simulation in this year we describe the further improvement in this tools as well as some new features we implemented focusing on heterogeneous robot models which seem to be used in RoboCup 2012.
An additional tool was written to simply generate situation-dependent strategies. Furthermore some tools, described last year, are now integrated in one single GUI to easy things up.
Existing approaches solving multi-vehicle pickup and delivery problems with soft time windows typically use common benchmark sets to verify their performance. However, there is a gap from these benchmark sets to real world problems with respect to instance size and problem complexity. In this paper we show that a combination of existing approaches together with improved heuristics is able to deal with the instance sizes and complexity of real world problems. The cost savings potential of the heuristics is compared to human dispatching plans generated from the data of a European carrier.
The concept of m-learning which differs from other forms of e-learning covers a wide range of possibilities opened up by the convergence of new mobile technologies, wireless communication structure and distance learning development. This process of converging has launched some new goals to support m-learning where heterogeneity of devices, their operating systems (Linux, Windows, Symbian, Android etc) and supported markup languages (WML, XHTML etc), adaptive content, preferences or characteristics of user have become some of the major problems to be solved. To facilitate the learning process even more and to establish literally anytime anywhere learning, learning material/content should be available to the user always even if the user is in offline. Multiple devices used by the same user should also be synchronized among themselves and with server to provide updated learning content and to give a freedom to the user to choose any device as per his/her convenience. In this paper software architecture has been proposed to solve these problems and has been implemented by using a multidimensional flashcard learning system which synchronizes among all the devices that are being used by the user.
Today's network landscape consists of quite different network technologies, wide range of end-devices with large scale of capabilities and power, and immense quantity of information and data represented in different formats. Research on 3D imaging, virtual reality and holographic techniques will result in new user interfaces (UI) for mobile devices and will increase their diversity and variety. A lot of efforts are being done in order to establish open, scalable and seamless integration of various technologies and content presentation for different devices including mobile considering individual situation of the end user. This is very difficult because various kinds of devices used by different users or in different times/parallel by the same user which are not predictable and have to be recognized by the system in order to identify device capabilities. Not only the devices but also Content and User Interfaces are big issues because they could include different kinds of data format like text, image, audio, video, 3D Virtual Reality data and other upcoming formats. A very suitable and useful example of the use of such a system is mobile learning because of the large amount of varying devices with significantly different features and functionalities. This is true not only to support different learners, e.g. all learners within one learning community, but also to support the same learner using different equipment parallel and/or at different times. Those applications may be significantly enhanced by including virtual reality content presentation. Whatever the purposes are, it is impossible to develop and adapt content for all kind of devices including mobiles individually due to different capabilities of the devices, cost issues and author‘s requirement. A solution should be found to enable the automation of the content adaptation process.
This paper describes the magmaOffenburg 3D simulation team trying to qualify for RoboCup 2012. While last year’s TDP focused on the tool set created for 3D simulation and the support for heterogeneous robot models, this year we focus on the different ways how robot behavior can be defined in the magmaOffenburg framework and how those behaviors can be improved by learning.
Responder-rate in cardiac resynchronization therapy (CRT) of patients in sinus rhythm (SR) or atrial fibrillation (AF) mainly depends on accurat selection, optimal position of the left ventricular electrode and individualization of hemodynamical parameters of the implanted biventricular pacing system during follow-up. High resolution esophageal left heart electrocardiography offers a quick and semi-invasive approach to the electrical activity of left atrium and left ventricle. It was used in 62 heart failure patients in sinus rhythm and 11 in atrial fibrillation after implantation of CRT systems to compare the semi-invasive interventricular conduction delay (IVCDE) with QRS width. In all of the patients, guideline decision for CRT was linked with IVCDE of about 40ms and up. From logical point of view, IVCDE provides the minimal target interval for the left ventricular electrode placement in order to exclude non-responders. Esophageal measurement of interatrial conduction intervals in VDD and DDD pacing was utilized to individualize the AV delay and to exclude adverse hemodynamic effects.
Capture threshold (CT) for transesophageal left atrial (LA) pacing (TLAP) and transesophageal left ventricular (LV) pacing (TLVP) with conventional cylindrical electrodes (CE) are higher than TLAP feeling threshold (FT). Purpose of the study was to evaluate focused TLAP CT and FT for supraventricular tachycardia (SVT) initiation and focused TLVP CT for cardiac resynchronisation therapy (CRT) simulation.
Methods: SVT initiation in patients (P) with palpitations (n=49, age 47 ± 17 years) was analysed during spontaneous rhythm and during focused bipolar TLAP with atrial constant current stimulus output, distal CE and three or seven 6 mm hemispherical electrodes (HE) (TO, Osypka AG, Rheinfelden, Germany). CRT simulation in heart failure P (n=75, age 62 ± 11 years) was evaluated by focused bipolar TLAP and/or TLVP with ventricular constant voltage stimulus output and different pacing mode.
Results: Focused electrical pacing field between CE and HE (n=28) allowed low threshold TLAP with 8.0 ± 2.6 mA CT at 9.9 ms stimulus duration (SD) which was lower than 9.2 ± 4.5 mA FT at 9.9 ms SD. Focused electrical pacing field between HE and HE (n=21) allowed low threshold TLAP with 8.1 ± 2.2 mA CT at 9.9 ms SD which was lower than 9.8 ± 5.0 mA FT at 9.9 ms SD. SVT initiation by programmed AAI TLAP was possible in 23 P and not possible in 26 P. CRT simulation was evaluated with TLAP and TLVP with VAT, D00 and V00 pacing mode and 95.5 ± 10.9 V TLVP CT at 4.0 ms SD.
Conclusions: Programmed focused AAI TLAP allowed initiation of SVT with very low CT and high FT and focused electrical pacing field between CE-HE and HE-HE.CRT simulation with focused TLAP and/or TLVP with VAT, D00 and V00 pacing mode may be a useful technique to detect responders to CRT.
Cardiac resynchronization therapy (CRT) with biventricular (BV) pacing is an established therapy in approximately two-thirds of symptomatic heart failure (HF) patients (P) with left bundle branch block (LBBB). The aim of this study was to evaluate left atrial (LA) conduction delay (LACD) and left ventricular (LV) conduction delay (LVCD) using pre-implantational transesophageal electrocardiography (ECG) in sinus rhythm (SR) CRT responder (R) and non-responder (NR).
Methods: SR HF P (n=52, age 63.6±10.4 years; 6 females, 46 males) with New York Heart Association (NYHA) class 3.0±0.2, 24.4±7.1 % LV ejection fraction and 171.2±37.6 ms QRS duration (QRSD) were measured by bipolar filtered transesophageal LA and LV ECG recording with hemispherical electrodes (HE) TO catheter (Osypka AG, Rheinfelden, Germany). LACD was measured between onset of P-wave in the surface ECG and onset of LA deflection in the LA ECG. LVCD was measured between onset of QRS in the surface ECG and onset of LV deflection in the LV ECG.
Results: There were 78.8 % SR CRT R (n=41) with 171.2±36.9 ms QRSD, 73.3±25.7 ms LACD, 80.0±24.0 ms LVCD and 2.3±0.5 QRSD-LVCD-ratio. SR CRT R QRSD correlated with LACD (r=0.688, P<0.001) and LVCD (r=0.699, P<0.001). There were 21.2 % SR CRT NR (n=11) with 153.4±22.4 ms QRSD (P=0.133), 69.8±24.8 ms LACD (n=6, P=0.767), 54.2±31.0 ms LVCD (P<0.0046) and 3.9±2.5 QRSD-LVCD-ratio (P<0.001). SR CRT NR QRSD not corre-lated with IACD (r=-0.218, P=0.678) and IVCD (r=0.042, P=0.903). During a 22.8±21.3 month CRT follow-up, the CRT R NYHA class improved from 3.1±0.3 to 1.9±0.3 (P<0.001). In CRT NR, NYHA class not improved (2.9±0.4 to 2.9±0.2, P=1) during 11.2±9.8 months BV pacing.
Conclusions: Transesophageal LA and LV ECG with HE can be utilized to analyse LACD and LVCD in HF P. Pre-implantational LVCD and QRSD-LVCD-ratio may be additional useful parameters to improve P selection for SR CRT.
Currently, QRS width and bundle branch block morphology are used as electrocardiographic guideline criterias to selectheart failure (HF) patients with interventricular desynchronization in sinus rhythm (SR) for cardiac resynchronisationtherapy (CRT). Nevertheless, up to 30% of these patients do not benefit from implantation of CRT systems. Esophagealleft ventricular electrogram (LVE) enables semi-invasive measurement of interventricular conduction delays (IVCD)even in patients with atrial fibrillation (AF). To routinely apply this method, a programmer based semi-invasiveautomatic quantification of IVCD should to be developed. Our aims were todefine interventricular conduction delaysby analyzing fractionated left ventricular (LV) deflections in the esophageal left ventricular electrogram of HF patientsin SR or AF.
In 66 HF patients (49 male,17 female, age 65 ± 10 years) a 5F TOslim electrode (Osypka AG, Germany) was perorallyapplied. Using BARD EP Lab, cardiac desynchronization was quantified as interval IVCD between onset of QRS insurface ECG and the investigator-determined onset of the left ventricular deflection in LVE. IVCD was compared withthe intervals between QRS onset and the first maximum (IVCDm1) and between QRS onset and the second maximum(IVCDm2) of the LV complex.
QRS of 173 ± 26 ms was linked with empirical IVCD of 75 ± 25 ms, at mean. First and second LV maximum could beascertained beyond doubt in all patients. Significant correlations of the p<0,01 level were found between IVCD and theIVCDm1 of 96 ± 28 ms as well as between IVCD and the IVCDm2 of 147 ± 31 ms, at mean. To standardize automatic measurement of interventricular conduction delays with respect to patients with fractionatedLV complexes, the first maximum of the LV deflection should be utilized to qualify the IVCD of HF patients with sinusrhythm and atrial fibrillation.
About 20% of those heart failure patients receiving cardiac resynchronization therapy (CRT) are in atrial fibrillation (AF). Current guidelines apply for patients in sinus rhythm only. Recent studies have shown again, that successful resynchronization is closely linked to a pre-existent ventricular desynchronization. In those studies, the interventricular conduction delay (IVCD) was determined prior to device implantation by ultrasound in patients with sinus rhythm (SR)only. In patients with AF this method ́s use is limited.
To implement left-heart electrogram (LHE) into standard programmers and to simplify IVCD measurement in heart failure patients with AF, LHE was recorded in 11 AF patients with heart failure by Biotronik ICS3000 programmer via a15Hz Butterworth high-pass filter. Therefore, TOslim esophageal electrode (Dr. Osypka GmbH, Rheinfelden, Germany) was perorally applied and fixed in position of maximal left ventricular defection. IVCD was measured between onset of QRS in surface ECG and left ventricular defection (LV) in LHE. In addition, intra-left ventricular conduction delay (ILVCD) was measured as duration of LV in LHE.
In all of the 11 AF patients, desynchronization was quantifiable by LHE. Mean QRS of 162 ± 27ms (120-206ms) was linked with IVCD of 62ms ± 27ms (37-98ms) and ILVCD of 110 ± 20ms (80-144ms), at mean. Correlation between IVCD and QRS was 0.39 (n. s.) with IVCD/QRS ratio of 0.38 ± 0.11 (0.22-0.81).
A 15Hz high-pass filtered LHE feature of the Biotronik ICS3000 programmer is feasible to quantify ventricular dyssynchrony in heart failure patients with AF in order to clearly indicate implantation of CRT systems. As relations between QRS duration, IVCD and ILVCD considerably differ interindividually, the predictive values of IVCD, ILVCD and IVCD/QRS ratio for individual CRT response or non-response shall be identified in follow-up studies.
ECG simulators, available on the market, imitate the electric activity of the heart in a simplified manner. Thus, they are suitable for education purposes but not really for testing algorithms to recognize complex arrhythmias needed for pacemakers and implantable defibrillators. Especially certain discrimination between various morphologies of atrial and ventricular fibrillation needs simulators providing native electrograms of different patients’ heart rhythm events. This explains the necessity to develop an ECG simulator providing high-resolution native intracardiac and surface electrograms of in-vivo rhythm events. In this paper we demonstrate an approach for an ECG simulator based on a consumer multichannel soundcard and a corresponding software application for a laptop computer. This Live-ECG Simulator is able to handle invasive electrogram recordings from electrophysiological studies and send the data to a modified external soundcard for subsequent digital to analog conversion. The hardware is completed with an electronic circuit providing level adjustment to adapt the output amplitude to the input conditions of several cardiac implants.
Cardiac resynchronization therapy with biventricular pacing is an established therapy for heart failure patients with electrical left ventricular desynchronization. The aim of this study was to evaluate left atrial conduction delay, intra left atrial conduction delay, left ventricular conduction delay and intra left ventricular conduction delay in heart failure patients using novel signal averaging transesophageal left heart ECG software.
Methods: 8 heart failure patients with dilated cardiomyopathy (DCM), age 68 ± 9 years, New York Heart Association (NYHA) class 2.9 ± 0.2, 24.8 ± 6.7 % left ventricular ejection fraction, 188.8 ± 15.5 ms QRS duration and 8 heart failure patients with ischaemic cardiomyopathy (ICM), age 67 ± 8 years, NYHA class 2.9 ± 0.3, 32.5 ± 7.4 % left ventricular ejection fraction and 167.6 ± 19.4 ms QRS duration were analysed with transesophageal and transthoracic ECG by Bard LabDuo EP system and novel National Intruments LabView signal averaging ECG software.
Results: The electrical left atrial conduction delay was 71.3 ± 17.6 ms in ICM versus 72.3 ± 12.4 ms in DCM, intra left atrial conduction delay 66.8 ± 8.6 ms in ICM versus 63.4 ± 10.9 ms in DCM and left cardiac AV delay 180.5 ± 32.6 ms in ICM versus 152.4 ± 30.4 ms in DCM. The electrical left ventricular conduction delay was 40.9 ± 7.5 ms in ICM versus 42.6 ± 17 ms in DCM and intra left ventricular conduction delay 105.6 ± 19.3 ms in ICM versus 128.3 ± 24.1 ms in DCM.
Conclusions: Left heart signal averaging ECG can be utilized to analyse left atrial conduction delay, intra left atrial conduction delay, left ventricular conduction delay and intra left ventricular conduction delay to improve patient selection for cardiac resynchronization therapy.
Cardiac resynchronization therapy (CRT) with biventricular pacing is an established therapy for heart failure (HF) patients (P) with ventricular desynchronization and reduced left ventricular (LV) ejection fraction. The aim of this study was to evaluate electrical right atrial (RA), left atrial (LA), right ventricular (RV) and LV conduction delay with novel telemetric signal averaging electrocardiography (SAECG) in implantable cardioverter defibrillator (ICD) P to better select P for CRT and to improve hemodynamics in cardiac pacing.
Methods: ICD-P (n=8, age 70.8 ± 9.0 years; 2 females, 6 males) with VVI-ICD (n=4), DDD-ICD (n=3) and CRT-ICD (n=1) (Medtronic, Inc., Minneapolis, MN, USA) were analysed with telemetric ECG recording by Medronic programmer 2090, ECG cable 2090AB, PCSU1000 oscilloscope with Pc-Lab2000 software (Velleman®) and novel National Intruments LabView SAECG software.
Results: Electrical RA conduction delay (RACD) was measured between onset and offset of RA deflection in the RAECG. Interatrial conduction delay (IACD) was measured between onset of RA deflection and onset of far-field LA deflection in the RAECG. Interventricular conduction delay (IVCD) was measured between onset of RV deflection in the RVECG and onset of LV deflection in the LVECG. Telemetric SAECG recording was possible in all ICD-P with a mean of 11.7 ± 4.4 SAECG heart beats, 97.6 ± 33.7 ms QRS duration, 81.5 ± 44.6 ms RACD, 62.8 ± 28.4 ms RV conduction delay, 143.7 ± 71.4 ms right cardiac AV delay, 41.5 ms LA conduction delay, 101.6 ms LV conduction delay, 176.8 ms left cardiac AV delay, 53.6 ms IACD and 93 ms IVCD.
Conclusions: Determination of RA, LA, RV and LV conduction delay, IACD, IVCD, right and left cardiac AV delay by telemetric SAECG recording using LabView SAECG technique may be useful parameters of atrial and ventricular desynchronization to improve P selection for CRT and hemodynamics in cardiac pacing.
New frontiers of supraventricular tachycardia and atrial flutter evaluation and catheter ablation
(2012)
Radiofrequency catheter ablation (RFCA) has revolutionized treatment for tachyarrhythmias and has become first-line therapy for some tachycardias. Although developed in the 1980s and widely applied in the 1990s, the technique is still in development. Transesophageal atrial pacing (TAP) can used for initiation and termination of supraventricular tachycardia (SVT).
Methods: The paroxysmal SVT include a wide spectrum of disorders including, in descending order of frequency, atrial flutter, atrioventricular (AV) nodal reentry, Wolff-Parkinson-White syndrome, and atrial tachycardia. While not life-threatening in most cases, they may cause important symptoms, such as palpitations, chest discomfort, breathlessness, anxiety, and syncope, which significantly impair quality of life. Medical therapy has variable efficacy, and most patients are not rendered free of symptoms. Research over the past several decades has revealed fundamental mechanisms involved in the initiation and maintenance of all of these arrhythmias. Knowledge of mechanisms has in turn led to highly effective surgical and catheter-based treatments. The supraventricular arrhythmias and their treatment are described in this report. SVT initiation was analysed with programmed TAP in 49 patients with palpitations (age 47 ± 17 years, 24 females, 25 males).
Results: In comparison to antiarrhythmic drug therapy the radiofrequency catheter ablation in patients suffering from atrial flutter, atrioventricular nodal reentry, atrioventricular reentry and atrial tachycardia is the better choice in most cases. TAP SVT initiation was possible in 23 patients before RFCA. Atrial cycle length of SVT was 320 ± 59 ms. We initiated AV nodal reentrant tachycardia (AVNRT, n=15), atrial tachycardia (AT, n=6) and AV reentrant tachycardia with Kent pathway conduction (AVRT, n=2) before RFCA.
Conclusions: Radiofrequency catheter ablation is a successful and safe method to cure most patients with paroxysmal supraventricular tachycardias. TAP allowed initiation and termination of SVT especially in outpatients.
This paper describes the magmaOffenburg 3D simulation team trying to qualify for RoboCup 2013. While last year’s TDP focused on different ways how robot behavior can be defined in the magmaOffenburg framework this year we focus on how we statistically evaluate new features on distributed systems. We also show some results gained through such analysis.
Automatic Meter Reading (AMR) is a major enabler for the upcoming smart grid. Potentially, it will be one of the first really large-scale M2M-communication solutions for sensor applications.
To date, the definition of the standardized communication stacks for Local Metrological Network (LMN) in AMR is still ongoing. This holds true both for ZigBee Smart Energy Profile and for Wireless M-Bus according to EN 13757. During this process, there is the necessity for flexible, albeit optimized solutions, which support the different existing and upcoming versions of the communication protocols. In the case of Wireless M-Bus, the major contender for European and possibly Asian installations, this is valid not only for the different operation modes (C-, N-, P-, Q-, R-, S-, and T-modes), which work in different frequencies (i.e. 868 MHz, 433 MHz, and 169 MHz) but also for the application layer, where additional bodies, like EN137575, Open Metering System (OMS) Group, or national bodies follow their approaches.
This contribution describes requirements, design techniques and experiences from the development of highly efficient Wireless M-Bus protocol stacks with support of good flexibility and portability between microcontroller platforms and RF-transceivers. The presented approach is not limited to the use of modern software engineering design processes, as such, but also includes essential additional features like testing or simulation, as well as tools for commissioning and monitoring.
In this paper we propose a motion framework forbipedal robots that decouples motion definitions from stabilizingthe robot. This simplifies motion definitions yet allows dynamicmotion adaptations. Two applications, walking and stopping onone leg, demonstrate the power of the framework. We show thatour framework is able to perform walking and stopping on one legeven under extreme conditions and improves walking benchmarkssignificantly in the RoboCup 3D soccer simulation domain.
Autonomous humanoid robots need high torque actuators to be able to walk and run. One problem in this context is the heat generated. In this paper we propose to use water evaporation to improve cooling of the motors. Simulations based on thermodynamic calculations as well as measurements on real actuators show that, under the assumption of the load of a soccer game, cooling can be considerably improved with relatively small amounts of water.
The formation of secondary phases in the porous electrodes is a severe mechanism affecting the lifetime of solid oxide fuel cells (SOFC). It can occur via various chemical mechanisms and it has a significant influence on cell performance due to pore clogging and deactivation of active surfaces and triple-phase boundary (TPB). We present a modeling and simulation study of nickel oxide formation (reoxidation) and carbon formation (coking) within the SOFC anode. We use a 2D continuum model based on a multi-phase framework [Neidhardt et al., J. Electrochem. Soc., 159, 9 (2012)] that allows the introduction of arbitrary solid phases (here: Ni, YSZ, NiO, Carbon) plus gas phase. Reactions between the bulk phases are modeled via interface-adsorbed species and are described by an elementary kinetic approach. Published experimental data are used for parameterization and validation. Simulations allow the prediction of cell performance under critical operation conditions, like (i) a non-fuel operation test, where NiO formation is taking place (Figure 1a), or (ii) an open circuit voltage (OCV) stability test under hydrocarbon atmosphere, where solid carbon is formed (Figure 1b). Results are applied for enhanced interpretation of experimental data and for prediction of safe operation conditions.
The IEEE802.11p standard describes a protocol for car-to-X and mainly for car-to-car-communication. It has found its place in hardware and firmware implementations and is currently tested in various field tests. In the research project Ko-TAG, which is part of the research initiative Ko-FAS, cooperative sensor technology is developed and its benefit for traffic safety applications is evaluated. A secondary radar principle based on communication signals enables localization of objects with simultaneous data transmission. It mainly concentrates on the detection of pedestrians and other vulnerable road users (VRU), but also supports pre crash safety applications. The Ko-TAG proposal enriches the current IEEE802.11p real-time characteristics needed for precise time-of-flight real-time localization. This contribution describes the development of a subsystem, which extends the functionality of IEEE802.11p and fits into the regulatory schemes. It discusses the approach for definition and verification of the protocol design, while maintaining the close coexistence with existing IEEE802.11p subsystems. System simulations were performed and hardware was implemented. The next step will be field measurements to verify the simulation results.
Das Ausmaß der elektrischen ventrikulären Desynchronisation bei reduzierter linksventrikulärer Funktion ist von Bedeutung für den Erfolg der Resynchronisationstherapie der Herzinsuffizienz mit biventrikulärer Stimulation. Das Ziel der Untersuchung besteht in der nichtinvasiven Messung der elektrischen inter-ventrikulären Desynchronisation mit und ohne ischämische Herzerkrankung bei kardialen Resynchronisationstherapie Respondern. Bei Patienten mit 25,3 ± 7,3 % reduzierter linksventrikulärer Ejektionsfraktion und 166,9 ± 38,5 ms QRS-Dauer wurde das transösophageale linksventrikuläre EKG abgeleitet. Die QRS-Dauer korrelierte mit dem interventrikulären und links-ventrikulären Delay bei Resynchronisationstherapie Respondern mit nicht-ischämischer Herzerkrankung.
Transösophageales interventrikuläres Delay bei Vorhofflimmern und kardialer Resynchronisation
(2013)
Die transösophageale linksventrikuläre Elektrokardiographie ermöglicht die Evaluierung der elektrischen ventrikulären Desynchronisation im Rahmen der kardialen Resynchronisationstherapie der Herzinsuffizienz. Das Ziel der Untersuchung besteht in der präoperativen Abschätzung des transösophagealen interventrikulären Delays bei Vorhofflimmern und kardialer Resynchronisationstherapie. Bei Patienten mit Vorhofflimmern, Herzinsuffizienz New York Heart Association Klasse 3,0 ± 0,2 und QRS-Dauer 159,6 ± 23,9 ms wurde das fokusierte transösophageale linksventrikuläre EKG abgeleitet. Die kardiale Resynchronisationstherapie Responder QRS-Dauer korrelierte mit dem transösophagealen interventrikulären Delay bei Vorhofflimmern.
Special implant connection module was developed to combine full features of two commercial heart rhythm simulators, ARSI-4 and Intersim II, into a master-slave teaching system. Seven workstations were equipped with the Carelink and Homemonitoring remote patient monitoring systems. This combination enables in-vitro training of physicians, nurses and students in pace-maker and defibrillator measurements during implantation and individual programming in the follow-up. Thus, extended sets of arrhythmias and electrode problems can be used to simulate problems and their solutions in a wide range of the clinical routine.
Decrease of non-responder rate is the main chal-lenge in cardiac resynchronization therapy. The problem could be solved, partly, in the follow-up by consequent indi-vidualization of hemodynamic pacing parameters. The eso-phageal electrogram feature of the Biotronik ICS 3000 programmer was used in the follow-up of 20 heart failure patients carrying implants for cardiac resynchronization therapy. Adverse hemodynamic programming of the sensed and paced AV delay could be easily observed and replaced by the individual optimal duration in 3 patients (15%) VDD and DDD operation.This result proves the value of esophageal electrogram recording CRT follow-up.
Network landscape of recent time contains many different network technologies, a wide range of end-devices with a large scale of capabilities and power, and an immense quantity of information and data represented in different formats. Research on 3D imaging, virtual reality and holographic techniques will result in new user interfaces (UI) for mobile devices, will increase their diversity and variety. In this paper software architecture has been proposed to establish device and content format independent communication including 3D imaging and virtual reality data as content. As experimental validation the concept is implemented in collaborative Language Learning Game (LLG), which is a learning tool for language acquisition.
The paper proposes a system architecture for charging infrastructure that serves the requirements of future fleets of shared-use electric vehicles in urban scenarios. The focus of the development is on the interfaces to central stakeholders such as mobility service providers, distribution network operators and utilities. The main concept of the proposed system is the adherence to a stringent resource-oriented design approach, following the design principles of the Representational State Transfer (REST) architectural software style for distributed systems. This design approach is used from the cloud-based services down to the implementation of the charging infrastructure's control algorithms. Focusing on the resources of the various entities simplifies the implementation of their interactions, compared to the explicit declaration of services that are available. The system design ensures that the charging infrastructure is open to all users and generates a benefit beyond basic charging operations. Integration in emerging smart markets is done via open web-based interfaces. These allow for the generation of an added value of concrete services for shared-use electric mobility. A link to the field of grid operation is proposed using the ISO/IEC 61850 telecontrol standard. The smart meter capabilities of the charging stations can be used to gain additional information on the current state of the distribution grid. As an exemplary service a load management service for a fleet of shared-use electric vehicles is going to be implemented.
This paper describes the new Sweaty humanoid adult size robot trying to qualify for the RoboCup 2014 adult size humanoid competition. The robot is built from scratch to eventually allow it to run. One characteristic is that to prevent the motors from overheating, water evaporation is used for cooling. The robot is literally sweating which has given it its name. Another characteristic is, that the motors are not directly connected to the frame but by means of beams. This allows a variable transmission ratio depending on the angle.
Since direct current high energy shock fulguration was initially performed in the mid 1980s, ablation of cardiac arrhythmias has come to widespread use. Today the most frequently used energy source for catheter ablation is radio frequency (RF). It was the German engineer Peter Osypka who made available the HAT 100 as the first simple commercial RF ablator.
Nevertheless, in the first years of ablation, physicians were effectively working in the dark. Until today with an increasing understanding of arrhythmia mechanisms, both at the atrial and ventricular levels, this curative technology has made tremendous progress. Now, due to crucial improvement of RF ablation generators, temperature and contact force sensor catheters in combination with non-flouroscopic electroanatomical mapping technologies, computerized temperature and impedance controlled radiofrequency catheter ablation can be used to cure all types of arrhythmias including atrial and ventricular fibrillation. For the latter, cooled ablation by saline solution irrigated catheters has been developed to a widely used standard method. This procedure resulting in pulmonary vein isolation requires transseptal puncture and is technically demanding. Nevertheless, it has shown to be more effective than antiarrhythmic drug therapy.
While earliest RF ablations were performed with non-steerable catheters, today are used steerable sensor catheters without or with external and internal cooling and tips of 4mm or 8mm length. Further innovations like integration of mapping and cardiac imaging give exact information of the number of pulmonary veins and branching patterns and help to correlate electrical signals with anatomical structures.
The magnetic navigation significantly improved the success rates and safety of catheter ablation. Thus, in most cases RF catheter ablation has developed in the treatment of supraventricular arrhythmias from an alternative approach to drug therapy into the first therapeutic choice providing low complication rates.
In future, robotic navigation will further simplify procedures and reduce radiation exposure of this curative approach.
Hintergrund: Das elektrische interventrikuläre Delay (IVD) und die Lage der linksventrikulären (LV) Elektrode zum Ort der spätesten LV Erregung sind bei Patienten (P) mit Herzinsuffizienz (HF), reduzierter LV Funktion und breiter QRS Dauer (QRSD) von Bedeutung für den Erfolg der kardialen Resynchronisationstherapie (CRT). Die LV Elektrokardiographie ermöglicht eine Abschätzung des elektrischen IVD. Ziel der Studie besteht in der nicht-invasiven Evaluierung des elektrischen IVD bei Patienten (P) mit Vorhofflimmern (AFib) mit und ohne CRT mit biventrikulärer (BV) Stimulation.
Methoden: Bei 49 HF P mit AFib (Alter 63,9 ± 10,8 Jahre; 43 Männer und 6 Frauen) mit New York Heart Association (NYHA) Klasse 2,9 ± 0,4, LV Ejektionsfraktion 26,03 ± 7,99 % und QRS-Dauer (QRSD) 143,69 ± 35,62 ms wurde das elektrische IVD als Intervall zwischen Beginn des QRS-Komplexes im Oberflächen EKG und Beginn des LV Signals im transösophagealen LV EKG bei 31 HF P mit AFib und bei 18 HF P mit AFib und CRT präoperativ bestimmt. Das fokussierte bipolare LV EKG wurde mittels Osypka TO Sonde mit halbkugelförmigen Elektroden in Höhe des maximalen LV Signals registriert.
Ergebnisse: Bei 31 HF P mit AFib betrugen QRSD 135,48 ± 38,78 ms, IVD 49,55 ± 26,38 ms, QRSD-IVD-Verhältnis 3,12 ± 1,11 und das IVD korrelierte mit der QRSD (r=0,75, P<0,001) und dem QRSD-IVD-Verhältnis (r=-0,67, P<0,001) (Fig.). Bei 18 HF P mit AFib und CRT Defibrillator betrugen QRSD 157,83 ± 24,38 ms, IVD 61,94 ± 26,88 ms, QRSD-IVD-Verhältnis 3,12 ± 1,89 und das IVD korrelierte mit der QRSD (r=0,47, P=0,049) und dem QRSD-IVD-Verhältnis (r=-0,73, P<0,001). Bei 72,2 % CRT Responder (R) (n=13) betrugen QRSD 158,15 ± 22,4 ms, IVD 64,23 ± 24,62 ms, QRSD-IVD-Verhältnis 2,82 ± 1,32 und das IVD korrelierte mit der QRSD (r=0,57, P=0,043) und dem QRSD-IVD-Verhältnis (r=-0,76, P=0,0024). Bei 27,8 % CRT Non-Responder (NR) (n=5) betrugen QRSD 157 ± 31,94 ms, IVD 56 ± 34,52 ms, QRSD-IVD-Verhältnis 3,88 ± 2,98 und das IVD korrelierte nicht mit der QRSD (r=0,33, P=0,591) und dem QRSD-IVD-Verhältnis (r=-0,732, P=0,159). Die CRT R verbesserten sich in der NYHA Klasse von 3 ± 0,2 auf 2,2 ± 0,3 (P<0,001) während 15,3 ± 13,1 Monaten BV Stimulation. Bei 15 CRT NR kam es zu keiner Verbesserung der NYHA Klasse von 3 auf 3,3 ± 0,97 (P=0,529) während 18,8 ± 20,7 Monaten BV Stimulation.
Schlussfolgerungen: Das transösophageale LV EKG ermöglicht bei HF-P mit AFib die nichtinvasive Messung des elektrischen IVD präoperativ vor CRT. IVD und QRSD-IVD-Verhältnis sind möglicherweise einfach anwendbare Parameter zur Vorhersage von CRT R und CRT NR bei P mit AFib.
Der Übergang Schule-Studium wird an der Hochschule Offenburg im Vorbereitungskurs Mathematik per Smartphone bzw. Tablet unterstützt. Eine Mathe-App gibt zu den Trainingsaufgaben bei Bedarf Tipps, Teilschritte und ausführliche Erklärungen und hilft so den Studierenden, die Lösungen in ihrer individuellen Lerngeschwindigkeit zu entwickeln. Der mobile Ansatz erlaubt, die ca. 400 Teilnehmer des Präsenz-Kurses in normalen Klassenräumen ohne PC-Ausstattung mit E-Learning vertraut zu machen und unterstützt die Flexibilisierung von Übungszeit und -ort über die Präsenzzeit hinaus. Durch die inhaltliche Orientierung am hochschulübergreifenden COSH (Cooperation Schule Hochschule) Mindestanforderungskatalog Mathematik entstand eine Lösung, die jedem Studienanfänger zur Vorbereitung auf das Studium nutzen kann, die zu den Brückenkurs-Inhalten vieler Hochschulen passt und für die aktuell schon Kooperationsprojekte mit Schulen starten.
Introduction: Radiofrequency ablation allows successful treatment of most supraventricular reentrant and focal tachycardias and an increasing number of ventricular tachycardias. Different catheter tips are used. While AV nodal reentrant tachycardias require catheters with a tip of 4mm length, an 8 mm tip electrodes will be used for atrial flutter. A pulmonary vein isolation will be performed using 4 mm irrigated tip electrodes to achieve larger and deeper lesions. The need of a tubing set and pump for saline transfusion is a disadvantage of this technique. Gold tip electrodes can alternatively be used to produce increases in lesion size. Aim of this study was to compare RF ablation catheters of exactly the same geometry with either platin-iridum or gold tip.
Methods: Gold provides an almost four-fold thermal conductivity compared with platinum-iridium. The Cerablate G flutter (Osypka AG, Rheinfelden-Herten) is a newly designed radiofrequency ablation catheter with an 8 mm gold tip. Its power delivery was compared with the Cerablate flutter of same geometry but platin-iridium tip. Therefore, in-vitro RF ablations were performed using pork meat in a 0.9% saline solution at 37°C temperature. A pulsed volume flow was generated using a pump to simulate the blood flow. Temperature controlled ablations of 60 seconds using 45, 55 and 65°C and a maximum of 70W RF power were performed.
Results: Using the Osypka HAT300smart ablator, cumulative power of 167, 474 and 672W was delivered with gold tip against 121, 227 and 310 W with platin-iridium tip. By the Stockert SmartAblate G4 ablator, 202, 546 and 1075W was delivered with gold tip against 117, 246 and 394W with platin-iridium using 45, 55 and 65°C temperature.
Conclusion: During in-vitro investigations, the gold tip electrodes allowed a in power delivery increase of 117 up to 173%. Thus, gold tips can be used to increase lesion depth and diameter without cooling equipment.
Der Übergang Schule-Studium wird an der Hochschule Offenburg im Vorbereitungskurs Mathematik per Smartphone bzw. Tablet unterstützt. Eine Mathe-App gibt zu den Trainingsaufgaben bei Bedarf Tipps und Teilschritte und hilft so den Studierenden, gemäß individuellem Tempo und Vorkenntnisstand zu arbeiten. Dies fördert eine Aktivierung der Kursteilnehmer auch bei großer Heterogenität. Der mobile Ansatz erlaubt, die ca. 400 Teilnehmer des Präsenz-Kurses in normalen Klassenräumen ohne PC-Ausstattung mit einem eCoach zu unterstützen und ermöglicht die Flexibilisierung von Übungszeit und –Ort über die Präsenzzeit hinaus.
Dieser für die heutige junge Generation attraktive Lernzugang entstand als Kooperationsprojekt zwischen der MassMatics UG und der Hochschule Offenburg. Durch die inhaltliche Orientierung am hochschulübergreifenden Mindestanforderungskatlog Mathematik des cosh-Arbeitskreises entstand eine Lösung, die jedem Studienanfänger zur Vorbereitung auf das Studium nutzen kann (auch ohne Präsenzkurs), die zu den Brückenkurs-Inhalten vieler Hochschulen passt und für die aktuell schon Kooperationsprojekte mit Schulen starten.
Das Projekt MINT-College TIEFE (Talente Individuell, Erfolgreich Fördern und Entwickeln) der Hochschule Offenburg wird im Rahmen des Bund-Länder-Programms Qualitätspakt Lehre aus Mitteln des Bundesministeriums für Bildung und Forschung (BMBF) unter dem Förderkennzeichen 01PL11016 gefördert. Unterstützt wird das Projekt vom Informationszentrum der Hochschule Offenburg.
Nowadays, it is assumed of many applications, companies and parts of the society to be always available online. However, according to [Times, Oct, 31 2011], 73% of the world population do not use the internet and thus aren't “online” at all. The most common reasons for not being “online” are expensive personal computer equipment and high costs for data connections, especially in developing countries that comprise most of the world’s population (e.g. parts of Africa, Asia, Central and South America). However it seems that these countries are leap-frogging the “PC and landline” age and moving directly to the “mobile” age. Decreasing prices for smart phones with internet connectivity and PC-like operating systems make it more affordable for these parts of the world population to join the “always-online” community. Storing learning content in a way accessible to everyone, including mobile and smart phones, seems therefore to be beneficial. This way, learning content can be accessed by personal computers as well as by mobile and smart phones and thus be accessible for a big range of devices and users. A new trend in the Internet technologies is to go to “the cloud”. This paper discusses the changes, challenges and risks of storing learning content in the “cloud”. The experiences were gathered during the evaluation of the necessary changes in order to make our solutions and systems “cloud-ready”.
Non-fluoroscopic Imaging with MRT/CT Image Integration - Catheter Positioning with Double Precision
(2014)
Introduction: When antiarrhythmic drug therapy has failed, different approaches of pulmonary vein isolation are considered a reasonable option in the treatment of atrial fibrillation. It will be performed predominantly by radiofrequency catheter ablation. As the individual anatomy of left atrium and the pulmonary veins differs considerably, accurate visualization of these structures is essential during catheter positioning. Using non-fluoroscopic electroanatomic mapping system with image integration, electroanatomic mapping can be combined with highly detailed anatomical MRT or CT information on complex left atrial structures. This may facilitate catheter navigation during ablation for atrial fibrillation.
Methods: The CARTO XP electroanatomic system was used in a project during biomedical engineering study to practice image integration of anonymized real patients that underwent pulmonary vein isolation by CARTO XP and a MRT/CT procedure. Using the image integration software, MRT or CT images were imported into the CARTO XP system. The next process was segmentation of the acquired images. It involves dividing the images into different regions in order to select the structures of interest. In clinical routine, this segmentation has to be performed before catheter ablation. Then, the segmented images were aligned with the reconstructed electroanatomic maps. This consists of several steps, including selection of the left atrium, scaling of the reconstructed geometry, fusion of the structures using landmarks, and optimization of the integration by adjusting the reconstructed geometry of the left atrium.
Results: In the 3 months lasting period of the project, image integration was trained in 13 patients undergoing catheter ablation for atrial fibrillation. Within this period, time consumption for the process decreased from about 90 minutes at the beginning to about 35 minutes at the end for one patient.
Conclusion: Image integration into non-fluoroscopic electroanatomic map is a sophisticated tool in cardiac radiofrequency catheter ablation. Intensive training is necessary to control the procedure.
Cardiac resynchronization therapy with atrioventricular and interventricular pacing delay optimized biventricular pacing is an established therapy for heart failure patients with sinus rhythm and reduced left ventricular ejection fraction. The aim of the study was to evaluate atrioventricular and interventricular pacing delay optimization in cardiac resynchroniza-tion therapy by transthoracic impedance cardiography in biventricular pacing with different left ventricular electrode po-sition. In biventricular pacing heart failure patients with lateral, posterolateral and anterolateral left ventricular electrode position, the mean optimal atrioventricular sening delay was 108.6 ± 20.3 ms and the mean optimal interventricular pac-ing delay -12.3 ± 25.9 ms. Transthoracic impedance cardiography may be a useful technique to optimize atrioventricular and interventricular pacing delay in biventricular pacing with different left ventricular electrode position.
Cardiac resynchronization therapy is an established therapy for heart failure patients with sinus rhythm, reduced left ventricular ejection fraction and prolongation of QRS duration. The aim of the study was to evaluate ventricular desynchronization with electrical interventricular delay (IVD) to left ventricular delay (LVD) ratio in atrial fibrillation heart failure patients. IVD and LVD were measured by transesophageal posterior left ventricular ECG recording. In atrial fibrillation heart failure patients with prolonged QRS duration, the mean IVD-to-LVD-ratio was 0.84 +/- 0.42 with a range from 0.17 to 2.2 IVD-to-LVD-ratio. IVD-to-LVD-ratio correlated with QRS duration. IVD-to-LVD-ratio may be a useful parameter to evaluate electrical ventricular desynchronization in atrial fibrillation heart failure patients.
Smoothie: a solution for device and content independent applications including 3D imaging as content
(2014)
Network landscape of recent time contains many different network technologies, a wide range of end-devices with a large scale of capabilities and power, and an immense quantity of information represented in different data formats. Research on 3D imaging, virtual reality and holographic techniques will result in new user interfaces (UI) for mobile devices and will increase their diversity and variety. A lot of effort is being made in order to establish open, scalable and seamless integration of various technologies and content presentation for different devices including those that are mobile, considering the individual situation of the end user. Till today the research is going on in different parts of the world but the task is not completed yet. The goal of this research work is to find a way to solve the above stated problems by investigating system architectures to provide unconstrained, continuous and personalized access to the content and interactive applications everywhere and at anytime with different devices. As a Solution of the problem considered, a new architecture named “Smoothie” is proposed.
E-Tutoren-Ausbildung: Lernerfahrungen reflektieren – Lehrhandlungskompetenzen dialogisch aufbauen
(2014)
The Internet of Things (IoT), ubiquitous computing and ubiquitous connectivity, Cyber Physical Systems (CPS), ambient intelligence, Machine-to-Machine communication (M2M) or Car-to-Car (C2C)-communication, smart metering, smart grid, telematics, telecare, telehealth – there are many buzzwords around current developments related to the Internet.
This contribution gives an overview on such IoT-applications, as they are already used today to improve the availability of information, increase efficiency, push system limits and extend the value chain. At a closer look, the economic and technical development can be separated into different phases. It is interesting that we are currently at the threshold to a new phase, with decentralized and cooperative communication and control nodes as cornerstones. Thus, embedded systems and their connectivity are in the middle of the scene.
This recent development is described along with some example projects from the author’s team which are used in industrial automation, energy supply and distribution (home automation and smart metering), traffic engineering (cooperative driver assistance systems), and in telehealth and telecare.
Transcatheter aortiv valve implantation is a new safe strategy treatment for patients with symptomatic severe aortic stenosis and high operative risk. The aim of the study was to compare the pre-and post- muiscatheter aortiv valve implantation procedures to determine the atrioventricuktr conduction time as a potential predictor of permanent pacemaker therapy requirement after transcatheter aortiv valve implantation. The transcatheter aortiv valve implantation patients were divided into groups without pacemaker and with dual or single chamber pacemEtker with diffent atrioventrieular conduction time disturbance before and after transcatheter aortiv valve implantation. In heart failure, patients without permanent pacemaker therapy after transcatheter aortiv valve implantation, atrioventricular conduction time was prolonged after transcatheter aortiv valve implantation. In patients with permanent dual chamber pacemaker therapy after transcatheter aortiv valve implantation, atrioventricular conduction time was normalised with dual chaniber atrioventrieuku pacing mode. Atrioventricular conduction time may be a useful parameter to evaluate the risk of post-procedural atrioventricular conduction block and permanent pacemaker therapy in transcatheter north, valve implantation patients.
Autonomous humanoid robots require light weight, high torque and high speed actuators to be able to walk and run. For conventional gears with a fixed gear ratio the product of torque and velocity is constant. On the other hand desired motions require maximum torque and speed. In this paper it is shown that with a variable gear ratio it is possible to vary the relation between torque and velocity. This is achieved by introducing systems of rods and levers to move the joints of our humanoid robot ”Sweaty II”. On the basis of a variable gear ratio low speed and high torque can be achieved for those joint angles, which require this motion mode, whereas high speed and low torque can be realized for those joint angles, where it is favorable for the desired motion.
Security in IT systems, particularly in embedded devices like Cyber Physical Systems (CPSs), has become an important matter of concern as it is the prerequisite for ensuring privacy and safety. Among a multitude of existing security measures, the Transport Layer Security (TLS) protocol family offers mature and standardized means for establishing secure communication channels over insecure transport media. In the context of classical IT infrastructure, its security with regard to protocol and implementation attacks has been subject to extensive research. As TLS protocols find their way into embedded environments, we consider the security and robustness of implementations of these protocols specifically in the light of the peculiarities of embedded systems. We present an approach for systematically checking the security and robustness of such implementations using fuzzing techniques and differential testing. In spite of its origin in testing TLS implementations we expect our approach to likewise be applicable to implementations of other cryptographic protocols with moderate efforts.
Im Projekt bwLehrpool wurde ein verteiltes System für die flexible Nutzung von Rechnerpools durch Desktop-Virtualisierung entwickelt. Auf Basis eines zentral gebooteten Linux- Grundsystems können beliebige virtualisierbare Betriebssysteme für Lehrund Prüfungszwecke zentral bereitgestellt und lokal auf den Maschinen aus-gewählt werden. Die verschiedenen Ar- beitsumgebungen müssen nicht mehr auf den PCs installiert werden und erlauben so eine multifunktionale Nutzung von PCs und Räumen für vielfältige Lehrund Lernszenarien sowie für elektronische Prüfungen. bwLehrpool abstrahiert von der PC-Hardware vor Ort und ermöglicht den Dozenten die eigene Gestaltung und Verwaltung ihrer Softwareumgebungen als Self-Service. Darüber hinaus fördert bwLehrpool den hochschulübergreifenden Austausch von Kursumgebungen.
The aim of this research work was to develop a boiler model with few parameters required for energy planning. The showcase considered for this work was the boiler system of the energy center at Offenburg University of Applied Sciences. A grey box model of the boiler was developed systematically starting from model abstraction, simplification, model break-down and to the use of empirical correlations wherever necessary to describe the intermediate effects along with the use of information from manufacturer’s specification in order to reduce parameters. This strategy had resulted in a boiler model with only 6 parameters, namely, nominal burner capacity, water gallery capacity, air ratio, heat capacity of wall, thermal conductance on flue gas and hot water side. Most of these parameters can be obtained through the information available in the spec sheets and thus an energy planner will be able to parameterize the model with low effort. The model was validated with the monitored data of the showcase. It was tested for the start-up, shut-down behavior and the effect of storage.
Environmental Monitoring is an attractive application field for Wireless Sensor Network (WSN). Water Level Monitoring helps to increase the efficiency of water distribution and management. In Pakistan, the world’s largest irrigation system covers 90.000 km of channels which needs to be monitored and managed on different levels. Especially the sensor systems for the small distribution channels need to be low energy and low cost. The distribution presents a technical solution for a communication system which is developed in a research project being co-funded by German Academic Exchange Service (DAAD). The communication module is based on IEEE-802.15.4 transceivers which are enhanced through Wake-On-Radio (WOR) to combine low-energy and real-time behavior. On higher layers, IPv6 (6LoWPAN) and corresponding routing protocols like Routing Protocol for Low power and Lossy Networks (RPL) can extend range of the network. The data are stored in a database and can be viewed online via a web interface. Of course, also automatic data analysis can be performed.
Der Studienbeginn wird an der Hochschule Offenburg durch Vorbereitungskurse, sogenannte Brückenkurse, unterstützt. Wir stellen vorläufige Ergebnisse beim Einsatz von Smartphones und Tablets im Rahmen des Physik-Brückenkurses vor, bei dem die Studenten Hilfen zum selbständigen Üben durch eine App erhalten. Durch die Überarbeitung des Kurses und den Einsatz der App konnte der Teilnehmerschwund verringert werden. Die Evaluationsergebnisse bestätigen eine hohe Akzeptanz der Neuerungen seitens der Studierenden. Erste Auswertungen von Ein- und Ausgangstests deuten darauf hin, dass durch den Brückenkurs eine Angleichung der Vorkenntnisse der Studienanfänger erreicht wird, da Teilnehmer mit geringeren Vorkenntnissen tendenziell einen größeren Lernfortschritt erreichen. Durch unterschiedliche Schwierigkeitsstufen und selbstregulierte Übungsphasen in individuellem Tempo können aber auch die Erfordernisse der stärkeren Teilnehmer angemessen berücksichtigt werden.
In der Wertanalyse ist die Methodik TRIZ (Theorie der Lösung erfinderischer Problemstellungen) seit vielen Jahren als Werkzeug zur Kostensenkung oder zur Steigerung der Funktionalität von Produkten bekannt. Seit ihrem ersten Bekanntwerden in Westeuropa hat sich auch TRIZ weiterentwickelt. So wurden Methoden zur Modellierung von Systemen inzwischen erweitert und um Werkzeuge zur schnellen Lösungsfindung, zur Fehlervoraussage und zur Produktplanung neu entwickelt. Durch den weltweiten wissenschaftlichen Fortschritt, die Verwendung unterschiedlicher Sprachen und neue Literatur ist andererseits auch die verwendete Terminologie angewachsen und nicht mehr eindeutig. Die neue VDI-Richtlinie 4521, von deren erstem Teil nun der Gründruck vorliegt, zielt deswegen auf eine Standardisierung der Terminologie und eine vereinheitlichte Beschreibung der Methoden ab. Mit ihrer Hilfe sollen das Studium der Methodik erleichtert, die Benutzung von Literatur vereinfacht und Inhalte der TRIZ klarer darstellbar werden.
The overview of public key infrastructure based security approaches for vehicular communications
(2015)
Modern transport infrastructure becomes a full member of globally connected network. Leading vehicle manufacturers have already triggered development process, output of which will open a new horizon of possibilities for consumers and developers by providing a new communication entity - a car, thus enabling Car2X communications. Nevertheless some of available systems already provide certain possibilities for vehicles to communicate, most of them are considered not sufficiently secured. During last 15 years a number of big research projects funded by European Union and USA governments were started and concluded after which a set of standards were published prescribing a common architecture for Car2X and vehicles onboard communications. This work concentrates on combining inner and outer vehicular communications together with a use of Public Key Infrastructure (PKI).
After having described many different aspects of our team software in previous years, in this paper we take the freedom to describe the magmaChallenge framework provided by the magmaOffenburg team. The framework is used as a benchmark tool to run different challenges like the running challenge in 2014 or the kick accuracy challenge in 2015. This description should serve as a documentation to simplify the maintenance by the community and to add new benchmarks in the future.
In contrast to conventional aortic valve replacement, the Transcatheter Aortic Valve Implantation (TAVI) is a new highly specialist alternative to surgical valve replacement for patients with symptomatic severe aortic stenosis and high operative risk. The procedure was performed in a minimally invasive way and was introduced at the university heart centre, Freiburg – Bad Krozingen in 2008. The results have been getting better and better over the years. The aim of the investigation is the analysis of electrocardiogram conduction time and the electrocardiography changes recorded hours and days after the procedure depending on artificial heart valve models, which may lead to pacemaker implantation, even the analysis of the effectiveness of treatment.
Transthoracic impedance cardiography (ICG) is a non-invasive method for determination of hemodynamic parameters. The basic principle of transthoracic ICG is the measurement of electrical conductivity of the thorax over the time. The aim of the study was the analysis of hemodynamic parameters from healthy individuals and the evaluation of various hemodynamic monitoring devices. Fourteen men (mean age 25 ± 4.59 years) and twelve women (mean age 24 ± 3.5 years) were measured during the cardiovascular engineering laboratory at Offenburg University of Applied Sciences, Offenburg, Germany. The ICG recordings were measured with the devices CardioScreen 1000, CardioScreen 2000 and TensoScreen with the corresponding Software Cardiovascular Lab 2.5 (Medis Medizinische Messtechnik GmbH, Illmenau, Germany). In order to create identical frame conditions, all measurements were recorded in the same position and for the same duration. Various positions were simulated from horizontal lying position to vertical standing position. Altogether, more than 30 hemodynamic parameters were measured.
Components of rocket engines as actively cooled combustion chambers must withstand high pressure as well as severe and complex thermal transients. While the thermal transients result in temperature gradients and, thus, in constraint thermal strains, the pressure load induces mean stresses. To assess the mechanical behaviour of such components during design via finite-element calculations, constitutive models are necessary that describe the time- and temperature-dependent plasticity of the material appropriately.
Advanced models account for viscoplastic deformations including isotropic and kinematic hardening, recovery and ratcheting. However, the models contain a relatively large number of temperature-dependent material properties that must be determined on the basis of data of material tests. The determination of the properties is a non-trivial task because it is not clear which loading history must be applied in the tests for a certain material to obtain stable and robust (i.e. objective) material properties. Consequently, the determined properties are depending on the underlying loading history in the tests as well as on the experience and valuation of the person that determined the properties. This results in uncertainties during the assessment of the components that must be faced with conservative designs leading to negative consequences in terms of mass and costs.
It is the aim of this work funded by the European Space Agency ESA to derive a procedure to determine stable and robust material properties of an advanced viscoplastic constitutive model for aerospace materials. To this end, a special loading history is applied in isothermal material tests conducted with copper at different temperatures in the temperature range from 300 to 700 K. To determine the material properties and to assess stability and robustness methods for numerical optimization as well as analytical and statistical methods are used. The determined material properties are validated on the basis of results of thermomechanical material tests also conducted in the temperature range from 300 to 700 K.
The ability to detect a signal masked by noise is improved in normal-hearing (NH) listeners when interaural phase differences (IPD) between the ear signals exist either in the masker or the signal. We determined the impact of different coding strategies in bilaterally implanted cochlear implant (BiCI) users with and without fine-structure coding (FSC) on masking level differences. First, binaural intelligibility level differences (BILD) were determined in NH listeners and BiCI users using their clinical speech processors. NH subjects (n=8) showed a significant mean BILD of 7.5 dB. In contrast, BiCI users (n=9) without FSC as well as with FSC revealed a barely significant mean BILD (0.4 dB respectively 0.6 dB). Second, IPD thresholds were measured in BiCI users using either their speech processors with FS4 or direct stimulation with FSC. With the latter approach, synchronized stimulation providing an interaural accuracy of stimulation timing of 1.67 µs was realized on pitch matched electrode pairs. The resulting individual IPD threshold was lower in most of the subjects with direct stimulation than with their speech processors. These outcomes indicate that some BiCI users can benefit from increased temporal precision of interaural FSC and adjusted interaural frequency-place mapping presumably resulting in improved BILD.
Agile Business Intelligence als Beispiel für ein domänenspezifisch angepasstes Vorgehensmodell
(2016)
Business-Intelligence-Systeme stellen durch ihre Unterstützung bei der Entscheidungsfindung für Unternehmen eine wichtige Rolle dar. Mit einer stetig dynamischeren Unternehmensumwelt geht daher die Anforderung nach der agilen Entwicklung dieser Systeme einher, so dass in der BI-Domäne zunehmend erfolgreich agile Methoden und Vorgehensmodelle eingesetzt werden. Die Weiterentwicklung und Anpassung von BI-Systemen ist dahingehend besonders, dass diese in der Regel langjährig gewachsenen Systemen und Strukturen betreffen, die strengen regulatorischen Rahmenbedingungen unterliegen, was eine Herausforderung für agile Vorgehensweisen darstellt. Wurden die Werte und Prinzipien des agilen Manifests [AM01] und die daraus abgeleiteten Methoden zu Beginn meist eins zu eins auf den Bereich BI übertragen, so hat sich das Verständnis von BI- Agilität als ganzheitliche Eigenschaft der BI im deutschsprachigen Raum etabliert, und agile Me- thoden wurden auf die Besonderheiten der BI-Domäne adaptiert. In diesem Beitrag werden BI-Agilität und Agile BI erläutert, ein Ordnungsrahmen für Maßnahmen zur Steigerung der BI-Agilität eingeführt sowie Herausforderungen bei Agile BI erläutert.
Institute of Reliable Embedded Systems and Communication Electronics, Offenburg University of Applied Sciences, Germany has developed an automated testing environment, Automated Physical TestBeds (APTB), for analyzing the performance of wireless systems and its supporting protocols. Wireless physical networking nodes can connect to this APTB and the antenna output of this attaches with the RF waveguides. To model the RF environment this RF waveguides then establish wired connection among RF elements like splitters, attenuators and switches. In such kind of set up it’s well possible to vary the path characteristics by altering the attenuators and switches. The major advantage of using APTB is the possibility of isolated, well controlled, repeatable test environment in various conditions to run statistical analysis and even to execute regression tests. This paper provides an overview of the design and implementation of APTB, demonstrates its ability to automate test cases, and its efficiency.
Wireless communication systems more and more become part of our daily live. Especially with the Internet of Things (IoT) the overall connectivity increases rapidly since everyday objects become part of the global network. For this purpose several new wireless protocols have arisen, whereas 6LoWPAN (IPv6 over Low power Wireless Personal Area Networks) can be seen as one of the most important protocols within this sector. Originally designed on top of the IEEE802.15.4 standard it is a subject to various adaptions that will allow to use 6LoWPAN over different technologies; e.g. DECT Ultra Low Energy (ULE). Although this high connectivity offers a lot of new possibilities, there are several requirements and pitfalls coming along with such new systems. With an increasing number of connected devices the interoperability between different providers is one of the biggest challenges, which makes it necessary to verify the functionality and stability of the devices and the network. Therefore testing becomes one of the key components that decides on success or failure of such a system. Although there are several protocol implementations commonly available; e.g., for IoT based systems, there is still a lack of according tools and environments as well as for functional and conformance testing. This article describes the architecture and functioning of the proposed test framework based on Testing and Test Control Notation Version 3 (TTCN-3) for 6LoWPAN over ULE networks.
BiCI users’ sensitivity to interaural phase differences for single- and multi-channel stimulation
(2016)
Energy and environment continue to be major issues of human mankind. This holds true on the regional, the national, and the global level. And it is one of the problems, where engineers and scientists in conjunction with political will and people's awareness, can find new approaches and solutions to save the natural resources and to make their use more efficient.
This paper describes the new Sweaty II humanoid adult size robot trying to qualify for the RoboCup 2016 adult size humanoid competition. Based on experiences during RoboCup 2014, the Sweaty robot has been completely redesigned to a new robot Sweaty II. A major change is the use of linear actuators for the legs. Another characteristic is its indirect actuation by means of rods. This allows a variable transmission ratio depending on the angle of a joint.
The humanoid Sweaty was the finalist in this year’s robocup soccer championship(adult size). For the optimization of the gait and the stability, data concerning forces and torques in the ankle joints would be helpful. In the following paper the development of a six-axis force and torque sensor for the humanoid robot Sweaty is described. Since commercial sensors do not meet the demands for the sensors in Sweatys ankle joints, a new sensor was developed. As a measuring devices we used strain gauges and custom electronics based on an acam PS09. The geometry was analyzed with the FEM program ANSYS to get optimal dimensions for the measuring beams. In addition ANSYS was used to optimize the position for the strain gauges on the beam.
In this TDP we describe a new tool created for testing the strategy layer of our soccer playing agents. It is a complete 2D simulator that simulates the games based on the decisions of 22 agents. With this tool, debugging the decision and strategy layer of our agents is much more efficient than before due to various interaction methods and complete control over the simulation.
In the future, the tool could also serve as a measure to run simulations of game series much faster than with the 3D simulator. This way, the impact of different play strategies could be evaluated much faster than before.