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In recent years, light-weight cryptography has received a lot of attention. Many primitives suitable for resource-restricted hardware platforms have been proposed. In this paper, we present a cryptanalysis of the new stream cipher A2U2 presented at IEEE RFID 2011 [9] that has a key length of 56 bit. We start by disproving and then repairing an extremely efficient attack presented by Chai et al. [8], showing that A2U2 can be broken in less than a second in the chosen-plaintext case. We then turn our attention to the more challenging known-plaintext case and propose a number of attacks. A guess-and-determine approach combined with algebraic cryptanalysis yields an attack that requires about 249 internal guesses. We also show how to determine the 5-bit counter key and how to reconstruct the 56-bit key in about 238 steps if the attacker can freely choose the IV. Furthermore, we investigate the possibility of exploiting the knowledge of a “noisy keystream” by solving a Max-PoSSo problem. We conclude that the cipher needs to be repaired and point out a number of simple measures that would prevent the above attacks.
Digital libraries are providing an increasing amount of data, which is normally structured in a classical way by documents and described by metadata as keywords. The data, even in scientific systems such as digital libraries and virtual research environments, will contain a great amount of noise or information unnecessary for our personal interests. Although there has been a lot of progress in the field of information retrieval, search techniques and other content finding methods, there is still much to be done in the field of information retrieval based on user behavior. This paper presents an approach deployed in the Humboldt Digital Library (HDL) to facilitate the retrieval of relevant information to the users of the system, making recommendations of paragraphs based on their profile and the behavior of other users who share similar profiles. The Humboldt digital library represents an innovative system of open access to the legacy of Alexander von Humboldt in a digital form on the Internet (www.avhumboldt.net). It contributes to the key question, how to present interconnected data in a proper form using information technologies.
Mit gleichem kommunalem Mehrzweck-Fahrzeug (Abb. 1) wurden mehrere Fahrzyklen mit konventionellem Dieselantrieb und mit parallelem diesel-elektrischem Hybridantrieb simuliert. Aus den Ergebnissen der realen Fahrzyklen mit konventionellem Dieselmotorantrieb ließen sich die Kraftstoffeinsparpotenziale mit dem Hybridmotor und den verschiedenen Maßnahmen wie Start-Stopp, Rekuperation und Boost ermitteln. Selbst bei diesem Kommunalfahrzeug lassen sich Kraftstoffeinsparungen bis über 20 % nachweisen, obwohl die Fahrzyklen für Hybridanwendungen nicht besonders attraktiv sind. Deutlich höhere Potenziale liegen beispielsweise bei Gabelstaplern und Baumaschinen vor.
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.
In previous work we [1] and other authors (e.g. [2]) have shown that agent-based systems are successful in optimizing delivery plans of single logistics companies and are meanwhile successfully productive in industry. In this paper we show that agent-based systems are particularly useful to also optimize transport across logistics companies. In intercompany optimization, privacy is of major importance between the otherwise competing companies. Some data has to be treated strictly private like the cost model or the constraint model. Other data like order information has to be shared. However, typically the amount of orders released to other companies has also to be limited. We show that our agent-based approach can be easily fine tuned to trade off privacy against the benefit of cooperation.
In the year 2009 several data privacy scandals have hit the headlines where major corporations had a legitimate need for detecting fraud conducted by their own employees, but chose inappropriate measures for data screening. This contribution presents architectures and pseudonymization technology for privacy compliant fraud screening or fraud detection, in order to reduce the number of undiscovered fraud cases and to reduce the time to discovery.
Auch wenn kaum eine andere Branche in Deutschland durch die weltweite Finanzkrise so stark getroffen wurde wie der Maschinenbau, gehört dieser nach wie vor zu den erfolgreichsten Branchen (vgl. VDMA 2010). In vielen Produktsegmenten sind deutsche Maschinenbauer Weltmarktführer. Jedoch stehen sie seit einigen Jahren Herausforderungen gegenüber, die zu einem Umdenken und einer Neuausrichtung führen. Insbesondere das nach wie vor existente Problem der Produktpiraterie sowie die zumeist aus den asiatischen Räumen eingetretenen Wettbewerber, die für einen enormen Preisdruck sorgen, haben in den letzten Jahren dazu geführt, dass Standardmaschinen nur noch eine geringe Profitabilität aufweisen. Mit produktbegleitenden Dienstleistungen (Services) hingegen lasst sich mit durchschnittlich 21 % eine rund viermal so hohe operative Marge realisieren wie mit Maschinen (vgl. Schmiedeberg/Strahle/Bendig 2010, S. 3). Annahmen gehen davon aus, dass Services das Potenzial haben, einen Umsatzanteil von bis zu 35 % und damit einen Gewinnanteil von bis zu 60 % zu erreichen.
Semi-invasive electromechanical target interval to guide left ventricular electrode placement
(2011)
Electrical velocimetry to optimize VV delay in biventricular VVIR and DDD pacing for heart failure
(2011)
Introduction: VV delay (VVD) is the only parameter to hemodynamically optimize cardiac resynchronization therapy (CRT) for patients with atrial fibrillation (AF). Electrical velocimetry (EV) has been established to monitor thoracic electrical conductivity and to calculate hemodynamic surrogate parameters. We compared the response of this method to hemodynamic parameter changes between CRT patients with sinus rhythm (SR) and patients with AF.
Methods: VVD was individualized in 17 CRT patients in SR (12m, 5f, 67.0±7.2yrs.) after echo AV delay optimization and in 11 CRT patients in AF (10m, 1f, 69.8±9.6yrs.) using the Aesculon Cardiovascular Monitor (Osypka Medical, Berlin, Germany). Serial 30s EV recordings were accomplished, decreasing the VVD stepwise by 10ms from +60ms to -60ms between right and left ventricular stimulus. Optimal VVD was determined by the maximum of at least two of the three averaged parameters stroke volume (SV), cardiac output (CO) and cardiac index (CI). The response of SV, CO and CI was tested comparing their values in optimal VVD and suboptimal VVD. Suboptimal VVD was defined by optimal VVD±20ms.
Results: In all 28 patients in SR and AF, EV recordings resulted in optimal VVD. Between suboptimal and optimal mean VVD of 18.6±30.8ms between left and right ventricular stimulus, SV increased by 7.2±6.8%, CO by 7.8±7.2% and CI by 10.0±13.3% (all p<0.02). In the SR group with VVD of 18.8± 29.6ms, SV increased by 4.6±2.9%, CO by 5.0±2.9% and CI by 4.9±2.9% (all p<0.02). In the AF group with VVD of 18.2±4.0ms, SV increased by 10.4±8.9%, CO by 11.3±9.5% and CI by 16.4±18.2% (all p<0.02). Significant differences were not found between optimal VVD in SR and AF patients.
Conclusion: EV is a feasible serial method to individualize VVD in DDD and VVIR pacing for heart failure. Its response to hemodynamic changes demonstrates the value of EV for VVD fine-tuning.
Surface and interface acoustic waves are two-dimensionally guided waves, as their displacement field is plane-wave like regarding its dependence on the spatial coordinates parallel to the guiding plane, while it decays exponentially along the axis normal to that plane. When propagating at the planar surface or interface of homogeneous media, they are non-dispersive. Another type of non-dispersive acoustic waves which is, however, one-dimensionally guided, has displacement fields localized near the apex of a wedge made of an elastic material. In this short review, their propagation properties are described as well as theoretical and experimental methods which have been used for their analysis. Experimental findings are discussed in comparison with corresponding theoretical work and potential applications of this fascinating type of acoustic waves are presented.
This study presents some results from a monitoring project with night ventilation and earthto-air heat exchanger. Both techniques refer to air-based low-energy cooling. As these technologies are limited to specific boundary conditions (e.g. moderate summer climate, low temperatures during night, or low ground temperatures, respectively), water-based low-energy cooling may be preferred in many projects. A comparison of the night-ventilated building with a ground-cooled building shows major differences in both concepts.
The German Weather Service (DWD) releases a heat warning, when the weather forecast provides a warm, humid, sunny, and windless weather condition during the next days. The heat stress is calculated by the so called Klima-Michel model. If the apparent air temperature exceeds ca. 32°C / 38°C, there is a strong / extreme heat stress. The smallest forecast area is each administrative district. As people (and especially the vulnerable population) stay most of the time indoors, the heat health warning system was extended by the prediction of heat stress in typical rooms. Therewith it is feasible to forecast the heat stress using a combination of the outdoor and indoor heat stress. The prediction for the indoor heat stress is based on the same weather forecast like the Heat Health Warning Systems (HHWS).and calculates the heat stress by the PMV-model (predicted mean vote). Based on a sophisticated data analysis and simulation study, realistic but summer-critical living situations were defined and implemented in the building simulation program ESP-r. As the simulation runs especially for extreme weather conditions, a simplified building model cannot be used. Standardized input/output routines and an adaptive handover of start values provide for short run times for each forecast area. Good building designs and urban planning provide effective measures to reduce heat stress in cities. However, we have to also pay attention to the present building stock under climate change and a higher heat-wave risk. The extended German HHWS provide information for the emergency services to support the social assistants during heat waves.
In large aircrafts the cabling is very complex and often causes reliability problems. This is specially true for modern In-flight Entertainment (IFE) systems, where every passenger can select a preferred movie, play computer games or be able to communicate with other travellers. Due to EMC problems, wireless communication systems (WiFi etc.) didn't succeed in solving these problems. In this paper an innovative communication system is proposed which perfectly supplements an aircraft IFE system. The key innovation of this system is to use structures that are essential parts of the airframe for data transfer, such as seat rails. Those rails consist of rectangular shapes and could easily be modified to fulfill the function of waveguides for microwaves. A waveguide as part of the seat rail would provide enormous benefits for aircrafts, such as a large bandwidth and consequently high data rates, no problems with EMC, unlimited flexibility of seat configuration, mechanical robustness with associated increase of reliability and a few additional advantages related to aircrafts such as reduction of weight and costs.
Home Care Applications and Ambient Assisted Living become increasingly attractive. This is caused as well by market pull, as the number of elderly people grows monotonously, as well as by technology push, as technological advances and attractive products pave the way to economically advantageous offerings. However, in real-life applications, a significant number of challenges remain. Those include seamless communication between products from different supplier, due to the lack of sufficiently standardized solutions, energy budgets, and scalability of solutions. This paper presents the experience from the InCASA project (Integrated Network for Completely Assisted Senior Citizen's Autonomy), where architectures for heterogeneous physical and logical communication flows are examined.
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.
A simple model is introduced that describes the interaction of surface acoustic waves (SAWs) with a 2D periodic array of objects on the surface that give rise to internal resonances. Such objects may be high-aspect ratio structures like micro-pillars fabricated of a material different from that of the substrate. The model allows for an approximate determination of the band structure for the acoustic modes in such systems. Results are presented for the dependence on structural parameters of a total bandgap in the non-radiative regime of a semi-infinite substrate, and it is shown how the frequency and radiation damping of vibrational modes can be determined that are associated with defects in the periodic 2D array.
In this paper we suggest to combine the areas of media streaming services, mobile devices, and manufacturing processes to support monitoring, controlling and supervising production processes in order to achieve high levels of efficiency and environmentally friendly production. It contains a comprehensive and detailed explanation of the proposed E-Learning streaming framework, especially the adaption of streaming services to mobile environments. The key components of our approach are 1) an XML-based streaming service specification language, 2) adaption of multimedia E-Learning services to mobile environments, and 3) a media delivery platform for searching, registration, and creation of streaming services for mobile devices.