CMT-conductivity-modulated transistor

The characteristics of a conductivity-modulated transistor which can control AC current are presented. Measured characteristics of a fabricated device are shown and compared with calculated characteristics. Calculations are based on a physical, one-dimensional analytical model which has been, in part, derived from numerical analysis of the device. The proposed model gives relatively good qualitative agreement between calculated and measured characteristics. Potential applications of the device are discussed     

Optimal Sorting Algorithms for a Simplified 2D Array with Reconfigurable Pipelined Bus System

In recent years, many researchers have investigated optical interconnections as parallel computing. Optical interconnections are attractive due to their high bandwidth and concurrent access to the bus in a pipelined fashion. The Linear Array with Reconfigurable Pipelined Bus System (LARPBS) model is a powerful optical bus system that combines both the advantages of optical buses and reconfiguration. To increase the scalability of the LARPBS model, we propose a two-dimensional extension: a simplified two-dimensional Array with Reconfigurable Pipelined Bus System (2D ARPBS). While achieving better scalability, we show the effectiveness of this newly proposed model by designing two novel optimal sorting algorithms on this model. The first sorting algorithm is an extension of Leighton's seven-phase columnsort algorithm that eliminates the restriction of sorting only an r times s array, where r ge s^2 , and sorts an n times n array in O(log n) time. The second one is an optimal multiway mergesort algorithm that uses a novel processor efficient two-way mergesort algorithm and a novel multiway merge scheme to sort n^2 items in O(log n) time. Using an optimal sorting algorithm Pipelined Mergesort designed for the LARPBS model as a building block, we extend our research on parallel sorting on the LARPBS to a more scalable 2D ARPBS model and achieve optimality in both sorting algorithms.     

Real-Time Vision and Speech Driven Avatars for Multimedia Applications

Recent progress in advanced video communication services and multimedia applications is grounded on novel human machine interfaces, improved usability, and user friendliness driven by user centric research and development. In this paper, we describe a complete system concept and algorithmic details of an example application within this area. The key features of the system are vision and speech based interfaces, which are used to animate an avatar for an audio-visual representation of a communication partner. The system is applied in two application scenarios, namely video chat and customer care services. Both applications are mass-market oriented and therefore careful design and development of robust and supporting user interfaces are required. The presented approach is integrated into a complete real-time prototype system, which is permanently demonstrated in the showcase at the head quarter of Deutsche Telekom, Bonn, Germany.     

Antireflection coated, wedged, single-crystal silicon aircraftwindow for the far-infrared

Operating far-infrared remote-sensing instruments from inside a pressurized cabin of an aircraft requires a window with high transmittance. Furthermore, the radiometric properties of the window, such as the transmittance and the emitted radiation (i.e., temperature distribution), have to be known. The design of a wedged, antireflection coated single-crystal silicon aircraft window, its modeled transmittance spectrum, and the applied coating technique are presented. Measurements of the window transmittance with the 2.5 THz heterodyne spectrometer TeraHertz OH-Measurement Airborne Sounder (THOMAS) and a Fourier-transform spectrometer are presented, showing a transmittance of about 90% around 84 cm^-1. The window was designed and built for the 2.5 THz OH-Sensor THOMAS, operated on the DLR research aircraft FALCON. The transmittance of 90% means a substantial improvement compared to the window used previously. With this new window, systematic errors in the measured atmospheric radiance could be lowered, making the retrieval of atmospheric parameters easier. Several successful flights with the new window up to an altitude of 43000 ft have already been performed     

On the cost of uniform protocols whose memory consumption is adaptive to interval contention

Recently, we introduced a novel term, memory-adaptive, whose goal it is to capture what it means for a distributed protocol to most efficiently make use of its shared memory. We proved three results that relate to the memory-adaptive model in the uniform setting. We considered a store/release protocol where processes are required to store a value in shared MWMR memory so that it cannot be overwritten until it has been released by the process. We showed that there do not exist uniformly wait-free store/release protocols using only the basic operations read and write that are memory-adaptive to point contention. We further showed that there exists a uniformly wait-free store/release protocol using only the basic operations read, write, and read-modify-write that is memory-adaptive to interval contention and time-adaptive to total contention. This left a significant gap — it remained open as to whether there exists a uniform, memory adaptive to interval contention store/release protocol that only uses read/write (no read-modify-write) registers. In this paper, we close this gap by showing that no such protocol can exist. We furthermore illustrate the validity and practicality of the concept of memory adaptiveness by providing a uniform, memory-adaptive to interval contention store/release protocol for Network Attached Disks.     

PLANNING TO OPTIMIZE THE UMTS CALL SETUP FOR THE EXECUTION OF MOBILE APPLICATIONS

The third generation of mobile communication, the so-called UMTS, makes a broad variety of applications for mobile terminals available. This endeavor is the maintenance of several applications on one terminal: Radio bearers have restrictions in the quality of service (QoS) for applications due to limited resources. And the cell setup for the execution of several mobile applications may lead to unacceptable waiting periods for the user. As example considers WAP access, where the connection to the gateway takes, in general, approximately half a minute. This period increases if one is using several applications on one mobile terminal. Another hinderance is an insufficient QoS availability during the call setup. Here, the execution of the mobile application is shutdown.

In this paper, the optimization of the call setup for several mobile applications is investigated. The optimization applies scheduling to order and optimize the execution of the modules for UMTS for the call setup. This application is new for scheduling in artificial intelligence (AI). The premise is the modularization of the UMTS call setup based on agent technology, since the call setup of radio is basically a continuous process in the field of electrical engineering. As a result, the user has a shorter waiting period until the execution of several mobile applications is started and thus mobile terminals can be used more flexibly. Experiments for the execution of up to 20 mobile applications on the same mobile terminal demonstrate the optimization.     

Sludge settling processes in SBR-related sewage treatment plants according to the Biocos method.

This paper describes the investigations in a sedimentation and circulation reactor (SU-reactor) of a three-phase Biocos plant. The aim of these investigations was the determination of the temporal and depth-dependent distribution of suspended solid contents, as well as describing the sludge sedimentation curves. The calculated results reveal peculiarities of the Biocos method with regard to sedimentation processes. In the hydraulically uninterrupted (pre-)settling phase, a sludge level depth was observed, which remained constant over the reactor surface and increased linearly according to the sludge volume. The settling and the thickening processes of this phase corresponded to a large extent to the well-known settling test in a one-litre measuring cylinder. During the discharge phase, the investigated settling rate was overlaid by the surface loading rate and the sludge level changed depending on the difference between those two parameters. The solid distribution of the A-phase indicated a formation of functional zones, which were influenced by the surface loading. The formation was comparable to the formation of layers in secondary settling tanks with vertical flow. The concentration equalisation between the biological reactor and the SU-reactor proved to be problematic during the circulation phase, because a type of internal sludge circulation occurred in the SU-reactor. A permanent sludge recirculation seems to be highly recommendable.     

In vitro toxicity tests of diethyleneglycol with cell cultures and an automated bacterial test system

Diethyleneglycol was tested for its general cytotoxic effects in three cell culture test systems and in a novel, automated bacterial test system. The first cytotoxic effects were detected in the cell culture test systems at DEG-concentrations of 1 g/1 and 3g/1. The bacterial test system showed a minimal inhibitory concentration of 5 g/1 DEG (20% growth reduction). Morphological observations showed evidence of membrane damage to the cultured cells by DEG. With the bacterial test system one could determine the amount of DEG semiquantitatively in wines to which this material had been added.