This paper presents dynamic behaviors of autonomous solid oxide fuel cells (SOFC) with AC bus control. Both voltage and frequency control are utilized to achieve load-sharing of the studied SOFC feeding isolated loads...
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This paper presents dynamic behaviors of autonomous solid oxide fuel cells (SOFC) with AC bus control. Both voltage and frequency control are utilized to achieve load-sharing of the studied SOFC feeding isolated loads. A DC-to-DC converter is connected to the output terminals of the studied SOFC for stabilizing output voltage and current fluctuations under different loading conditions. The PWM inverter connected to the output terminals of the DC-to-DC converter is operated under voltage-controlled mode to regulate the voltage profile across the connected loads. It can be concluded from the simulation results that the proposed voltage and frequency droop controllers of the PWM inverter may operate satisfactory under stand-alone mode.
This paper is dealing with redundant optoelectronic data transmission with special respect to laser channels. The concept of the generalized erasure channel (GEC) is used to determine the probability of undetected err...
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This paper is dealing with redundant optoelectronic data transmission with special respect to laser channels. The concept of the generalized erasure channel (GEC) is used to determine the probability of undetected error for some binary symmetric and non-symmetric channels protected by appropriate codes. In detail, communication via different binary symmetric channels (BSCs), generalized erasure channels and symmetrized binary non symmetric channels (BNSCs) is investigated. Simple upper bounds are given, relating the new formulas to that one of the BSC Finally the results in connection with an inequality for proper codes are applied to multi wavelength optical transmission through channels generated by semiconductor lasers.
Developing security-critical applications is very difficult and the past has shown that many applications turned out to be erroneous after years of usage. For this reason it is desirable to have a sound methodology fo...
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Experimenters in biomedical image processing rely on software libraries to provide a large number of standard filtering and image handling algorithms. The Insight Toolkit (ITK) is an open-source library that provides ...
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ISBN:
(纸本)9789898111050
Experimenters in biomedical image processing rely on software libraries to provide a large number of standard filtering and image handling algorithms. The Insight Toolkit (ITK) is an open-source library that provides a complete framework for a range of image processing tasks, and is specifically aimed at segmentation and registration tasks for both two and three dimensional images. This paper describes a visual dataflow language, ITKBoard, designed to simplify building, and more significantly, experimenting with ITK applications. The ease with which image processing experiments can be interactively modified and controlled is an important aspect of the design. The experimenter can focus on the image processing task at hand, rather than worry about the underlying software. ITKBoard incorporates composite and parameterised components, and control constructs, and relies on a novel hybrid dataflow model, combining aspects of both demand and data-driven execution.
computer science and engineering communities have been exploring a variety of activities and techniques to attract and retain more students, especially women and minorities, to computer science and computer engineerin...
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computer science and engineering communities have been exploring a variety of activities and techniques to attract and retain more students, especially women and minorities, to computer science and computerengineering degree programs1. This paper briefly describes the efforts and results of a plan for actively recruiting young women into undergraduate computerengineering and computer science programs hosted by the University of North Texas (UNT). It also describes a series of activities aimed at improving the retention rate of students already in our programs, particularly during the freshman year. Such recruitment and retention efforts are critical to the country's efforts to increase the number of engineering professionals, and are a priority for the computer Science and engineering (CSE) Department at UNT. We initially designed a three-part plan to achieve our recruitment and retention goals: Sponsorship of portable and mobile summer computerengineering robotics camps for middle and high-school women students, coordinating with the regional Girl Scouts councils and other organizations to help with the recruitment;Creation of an Ambassador program using young women currently enrolled in the upper division of current computer science and computerengineering programs as a form of outreach to area high schools and junior colleges;and Expansion of our successful undergraduate mentoring program by using the Ambassador cohort mentioned above as mentors for incoming freshman and first-year transfer women entering our programs. This paper will focus primarily on the summer camp program and present an analysis of the results we have seen to date after 2 years of camp activities. Results from student surveys and parent surveys will be presented. The paper concludes with recommended changes and improvements in the program, as well as a discussion of adaptations that would create programs suitable for implementation at other institutions as well as programs aimed at a dif
With single thread performance starting to plateau, HW architects have turned to chip level multiprocessing (CMP) to increase processing power. All major microprocessor companies are aggressively shipping multi-core p...
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ISBN:
(纸本)1595936025
With single thread performance starting to plateau, HW architects have turned to chip level multiprocessing (CMP) to increase processing power. All major microprocessor companies are aggressively shipping multi-core products in the mainstream computing market. Moore's law will largely be used to increase HW thread-level parallelism through higher core counts in a CMP environment. CMPs bring new challenges into the design of the software system stack. In this tutorial, we talk about the shift to multi-core processors and the programming implications. In particular, we focus on transactional programming. Transactions have emerged as a promising alternative to lock-based synchronization that eliminates many of the problems associated with lock-based synchronization. We discuss the design of both hardware and software transactional memory and quantify the tradeoffs between the different design points. We show how to extend the Java and C languages with transactional constructs, and how to integrate transactions with compiler optimizations and the language runtime (e.g., memory manager and garbage collection).
Because they are easy to create and modify, low fidelity prototypes are commonly used in early evaluations of user interface designs. Designers typically use either pen-and-paper or various computer-based tools to cre...
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ISBN:
(纸本)1595936424
Because they are easy to create and modify, low fidelity prototypes are commonly used in early evaluations of user interface designs. Designers typically use either pen-and-paper or various computer-based tools to create and test low fidelity prototypes;however, our informal analyses of these existing technologies indicate that they do not optimally support the two key, complementary tasks of (a) prototype creation and (b) wizard of oz testing. To address this problem, we have been developing WOZ Pro (Wizard of Oz Prototyper), a pen-based software environment for the quick and easy creation and testing of low fidelity user interface prototypes. We are designing WOZ Pro to be as easy to use as pen-and-paper, but to hold key advantages over pen-and-paper and existing computer-based tools. When designing interface screens in WOZ Pro, designers can easily (a) propagate a design change to other related screens, and (b) specify the set of screens that are reachable from a given screen. In a wizard of oz test, WOZ Pro reduces the cognitive load on the wizard by allowing navigation only to those next screens that are valid. We are planning a controlled experiment to compare WOZ Pro against paper-and-pencil along several measures in a set of prototype creation and evaluation tasks.
Developing security-critical applications is very difficult and the past has shown that many applications turned out to be erroneous after years of usage. For this reason it is desirable to have a sound methodology fo...
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Developing security-critical applications is very difficult and the past has shown that many applications turned out to be erroneous after years of usage. For this reason it is desirable to have a sound methodology for developing security-critical e-commerce applications. We present an approach to model these applications with the Unified Modeling Language (UML) [1] extended by a UML profile to tailor our models to security applications. Our intent is to (semi-) automatically generate a formal specification suitable for verification as well as an implementation from the model. Therefore we offer a development method seamlessly integrating semi-formal and formal methods as well as the implementation. This is a significant advantage compared to other approaches not dealing with all aspects from abstract models down to code. Based on this approach we can prove security properties on the abstract protocol level as well as the correctness of the protocol implementation in Java with respect to the formal model using the refinement approach. In this paper we concentrate on the modeling with UML and some details regarding the transformation of this model into the formal specification. We illustrate our approach on an electronic payment system called Mondex [10]. Mondex has become famous for being the target of the first ITSEC evaluation of the highest level E6 which requires formal specification and verification.
The Haskell String type is notoriously inefficient. We introduce a new data type, ByteString, based on lazy lists of byte arrays, combining the speed benefits of strict arrays with lazy evaluation. Equational transfor...
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ISBN:
(纸本)9783540696087
The Haskell String type is notoriously inefficient. We introduce a new data type, ByteString, based on lazy lists of byte arrays, combining the speed benefits of strict arrays with lazy evaluation. Equational transformations based on term rewriting are used to deforest intermediate ByteStrings automatically. We describe novel fusion combinators with improved expressiveness and performance over previous functional array fusion strategies. A library for ByteStrings is implemented, providing a purely functional interface, which approaches the speed of low-level mutable arrays in C.
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