11513370
A Quantitative Evaluation of Cache Types for High-Performance Computer Systems
Parallel accesses to the table lookaside buffer (TLB) and cache array are crucial for high-performance computer systems, and the choice of cache types is one of the most important factors affecting cache performance. The authors classify caches according to both index and tag. Since both index and tag could be either virtual (V) or real (R), their classification results in four combinations or cache types. The real address caches with virtual tags for high-performance computer systems in this study are prediction-based, since index bins are generated from a small array and predictions could be false. As a result, they also discuss and evaluate real address MRU caches with real tags, and propose virtually indexed MRU caches with real tags. Each of the four cache types and MRU caches are discussed and evaluated using trace-driven simulation. The results show that a virtually indexed MRU cache with real tags is a good choice for high-performance computer systems. >
40872599
Timestamp consistency and trace-driven analysis for distributed parallel systems
A continuous stream of event data describing the progress of parallel program execution is realized for trace-driven analysis. Unfortunately, it is often the case that separate streams are produced independently by multiple processors in the system, and the logical order of events cannot be guaranteed due to discrepancy among local clocks. We present an integrated approach for timestamp consistency and performance analysis techniques for IBM SPn systems. The trace facility requires no source code modification, and can generate message passing and system events with minimal trace overhead. Trace-driven analysis tools are developed to extract useful information. Analysis results for NAS kernel benchmarks are reported.<<ETX>>
38476421
Design Trade-offs for Process Scheduling in Tightly Coupled Multiprocessor Systems
8015300
MPI programming environment for IBM SP1/SP2
In this paper we discuss an implementation of the message passing interface standard (MPI) for the IBM Scalable Power PARALLEL 1 and 2 (SP1, SP2). Key to a reliable and efficient implementation of a message passing library on these machines is the careful design of a UNIX-Socket like layer in the user space with controlled access to the communication adapters and with adequate recovery and flow control. The performance of this implementation is at the same level as the IBM-proprietary message passing library (MPL). We also show that in the IBM SP1 and SP2 we achieve integrated tracing ability, where both system events, such as context switches and page fault etc., and MPI related activities are traced, with minimal overhead to the application program, thus presenting application programmers the trace of all the events that ultimately affect efficiency of a parallel program.
7845091
A Hybrid Number System Processor with Geometric and Complex Arithmetic Capabilities
The architecture, design, and performance of a hybrid number system processor are described. The processor performs multiplication, division, square root, and square in the logarithmic number system (LNS) domain. However, the input, output, addition, and subtraction are all executed in the 32-b IEEE standard floating-point number system. With the LNS multiplier and pipelined architecture, the processor is able to perform the geometric and complex arithmetic very effectively. The processor is also shown to compare well to an existing 32-b floating-point DSP (digital signal processor) chip. For the same level of CMOS technology, the performance ratios between the hybrid number system and the floating-point processor are shown to be 6.4:1 and 8:1 for division and square root, respectively; for the complex FFT (fast Fourier transform) algorithm, the ratio is around 2:1. >
463160
A Rule-Based Circuit Representation for Automated CMOS Design and Verification
A novel rule-based circuit representation is proposed to describe the connectivities of CMOS circuits at the transistor level. The unique feature of the rule-based representation is its ability to automate CMOS circuit design and verification. A precise symbolic description of the functionality of a transistor-level circuit can be derived based on a set of production rules in linear time. Automated synthesis and verification of CMOS logic circuits are demonstrated.
414035
Internet voting: concerns and solutions
Internet voting systems, catering to different requirements, have been widely implemented and used. Some have been successful, while others have experienced unexpected problems. This paper overviews the concerns of using Internet voting and tries to give solutions. Tradeoffs between the advantages and disadvantages of employing Internet voting are also addressed. A simple protocol is designed to show that technical problems identified in the literature can be solved fairly easily, though some seem subtle. This study reveals that the main concerns of adopting Internet voting for critical elections are not cryptographic tools, but hardware and software reliability, and social and political issues. After discussing possible concerns about Internet voting and possible solutions or comments, we propose steps to enable Internet voting to be adopted even for critical elections.
7629632
Speech content authentication integrated with CELP speech decoders
A speech content authentication scheme, which is integrated with CELP speech coders to minimize the total computational cost is proposed in this research. Speech features relevant to semantic meaning are extracted, encrypted and attached as the header information. A low cost synchronization algorithm is used to resolve mis-synchronization caused by content preserving operations. Silent and tonal regions in the speech are identified with algorithms of low complexity to enhance the precision of integrity verification. This scheme is not only much faster than traditional cryptographic bitstream integrity algorithms, but also more compatible for a variety of applications. Experimental results are collected by using the GSM-AMR speech coder, and statistical analysis is performed to calculate the false positive rate of tamper detection.
2900154
Learning simulation through team projects
For several years, team projects have been an integral part of the simulation course at the department of Industrial and Operations Engineering at the University of Michigan. We believe that team projects are an effective tool for learning how to perform simulation. In this paper, we present a brief summary of research on cooperative learning from the field of education research. Based on findings from that research, we present the procedure we follow in assigning, running, and evaluating team projects during an academic semester. We analyze students' responses to a survey on their preference and perceived value of the team project as conducted in this course. Two student papers, published in this conference, provide for examples of completed team projects.
14697178
Design of integrated multimedia compression and encryption systems
Two approaches for integrating encryption with multimedia compression systems are studied in this research, i.e., selective encryption and modified entropy coders with multiple statistical models. First, we examine the limitations of selective encryption using cryptanalysis, and provide examples that use selective encryption successfully. Two rules to determine whether selective encryption is suitable for a compression system are concluded. Next, we propose another approach that turns entropy coders into encryption ciphers using multiple statistical models. Two specific encryption schemes are obtained by applying this approach to the Huffman coder and the QM coder. It is shown that security is achieved without sacrificing the compression performance and the computational speed. This modified entropy coding methodology can be applied to most modern compressed audio/video such as MPEG audio, MPEG video, and JPEG/JPEG2000 images.
53305921
Substring selection for biomedical document classification
Motivation: Attribute selection is a critical step in development of document classification systems. As a standard practice, words are stemmed and the most informative ones are used as attributes in classification. Owing to high complexity of biomedical terminology, general-purpose stemming algorithms are often conservative and could also remove informative stems. This can lead to accuracy reduction, especially when the number of labeled documents is small. To address this issue, we propose an algorithm that omits stemming and, instead, uses the most discriminative substrings as attributes. 
 
Results: The approach was tested on five annotated sets of abstracts from iProLINK that report on the experimental evidence about five types of protein post-translational modifications. The experiments showed that Naive Bayes and support vector machine classifiers perform consistently better [with area under the ROC curve (AUC) accuracy in range 0.92--0.97] when using the proposed attribute selection than when using attributes obtained by the Porter stemmer algorithm (AUC in 0.86--0.93 range). The proposed approach is particularly useful when labeled datasets are small. 
 
Contact: vucetic@ist.temple.edu 
 
Supplementary Information: The supplementary data are available from www.ist.temple.edu/PIRsupplement