Kin Fun Li

A resilient mutual exclusion algorithm for computer networks

The authors present an extension to the work of I. Suzuki and T. Kasami (see Proc. 3rd Int. Conf. Distributed Compact Syst., p.365-70 (1982)), where a mutual exclusion algorithm uses a message called a token to transfer the privilege of entering a critical region among the participating sites. The proposed algorithm checks whether the token is lost during network failure, and regenerates it if necessary. The mutual exclusion requirement is satisfied by guaranteeing regeneration of only one token in the network. Failures in a computer network are classified into three types: processor failure, communication controller failure, and communication link failure. To detect failures, a time-out mechanism based on message delay is used. The execution of the algorithm is described for each type of failure; each site follows a rather simple execution procedure. Each site is not required to observe the failure of other sites or communication links. >

Smart home technology for telemedicine and emergency management

With the ageing population, mobility is an important issue and it deters the elderlies to visit health clinics on a regular basis. Individuals with disabilities also face the same obstacles for their out-of-home medical visits. In addition, people living in remote areas often do not get the needed health care attention unless they are willing to spend the time, effort and cost to travel. Advances in information and telecommunication technologies have made telemedicine possible. Using the latest sensor technologies, a person’s vital data can be collected in a smart home environment. The bio-information can then be transferred wirelessly or via the Internet to medical databases and the healthcare professionals. Using the appropriate sensing apparatus at a smart home setting, patients, elderlies and people with disabilities can have their health signals and information examined on a real-time and archival basis. Recovery process can be charted on a regular basis. Remote emergency alerts can be intercepted and responded quickly. Health deterioration can be monitored closely enabling corrective actions. Medical practitioners can therefore provide the necessary health-related services to more people. This paper surveys and compiles the state-of-the-art smart home technologies and telemedicine systems.

A Web-Based Sign Language Translator Using 3D Video Processing

The American Sign Language (ASL) is used by hearing-impaired people in North America, as well as in other parts of the world to supplement indigenous sign language. A proof-of-concept ASL Translator has been designed and developed using 3D video processing techniques. Foreseeing its potential as a Web-based application, the Translator must have a portable input device to capture gestures and its cost must be kept low. The recently introduced Xbox Kinect is a versatile gesture input device and fits the low-cost requirement as well. 3D data of the joints of a user captured by the Kinect are analyzed and matched to a library of pre-recorded signs. The matched signs are then transcribed to word or phrase, and output to a suitable user interface. The implemented prototype works with excellent accuracy for a limited vocabulary. Using the Web and a server to archive the pre-recorded signs and to process recorded gesture via a motion capture device, there are many potential applications. The Translator can be utilized as an assistive tool for the hearing impaired to communicate or as a teaching tool for those who want to learn the sign language.

A quantitative study for Java microprocessor architectural requirements. Part II: high-level language support

Abstract Java was designed for network programming. This imposes certain requirements on its virtual machine instruction set architecture and on designs that intend to support Java. The purpose of this study is to carry out a behavioral analysis of the different aspects of Java instruction set architecture. Performance metrics were collected through benchmarking a bytecode interpreter. In this second part of our two-part paper, we study the instruction set utilization, instruction execution time, method invocation behavior, and the effect of object-orientation.

A quantitative study for Java microprocessor architectural requirements. Part I: Instruction set design

Abstract Java was designed for network programming. This imposes certain requirements on its virtual machine instruction set architecture and on designs that support Java. The purpose of this study is to carry out a behavioral analysis of the different aspects of Java instruction set architecture. This will help in establishing the hardware requirements for executing Java bytecodes. First, the bytecode interpreter was instrumented to include performance counters and statistics collectors. Then performance metrics were collected through benchmarking. Analyzing these data helps to identify performance-critical aspects that are candidates for hardware support, while less critical aspects can be left for software implementations. In this first part of our two-part paper, we study access patterns for data types, addressing modes, and instruction encoding. Recommendations for architectural requirements for Java processors will be made throughout this study.

Building an Adaptive Multimedia System using the Utility Model

We present our experience of building a prototype system based on the Utility Model for adaptive multimedia. The Utility Model is proposed to capture the issues and dynamics in multi-session multimedia systems where the quality of service (QoS) of individual sessions is adapted to dynamic changes of available resources and of user preferences. We present the design and implementation of our prototype multimedia system, and report experimental results. We demonstrate that the Utility Model supports two types of adaptation: reactive adaptation for systems where only a subset of the applications follows the adaptation model, and proactive adaptation for systems where all the applications follow the adaptation model. Our results demonstrate that the Utility Model may be effectively used for dynamic quality adaptation in real-time multimedia systems.

Parallel Computation of Similarity Measures Using an FPGA-Based Processor Array

An enormous amount of data needs to be processed in many data mining applications. In addition to algorithmic development, hardware support is imperative to improve the effectiveness and efficiency of these applications. We are investigating various hardware architectural design techniques and methodologies to support data mining at the chip level. In this work, we focus on the design of an FPGA-based processor array for the computation of similarity matrix, a commonly used data structure to represent the similarity among a set of feature vectors, with each matrix element representing the computed similarity measure between two vectors. An algorithm is developed to assign computation efficiently to the array of processing elements. Theoretical performance metrics are derived and compared to the experimental results. Performance gains using the processor array over software implementations are also presented and discussed.

Optimal quality of service routing and admission control using the utility model

Real-time multimedia applications such as video and audio streaming, video conferencing and online collaboration are becoming increasingly popular. In order to guarantee effective support of many of these applications, the Internet must provide absolute Quality of Service(QoS) guarantees for such parameters as network bandwidth and end-to-end delay by incorporating session admission control, session routing, and resource reservation. In this article, we present the Utility Model for optimal routing and admission control (RAC) of a data network supporting sessions requiring QoS guarantees. This model maps the optimal RAC problem to a Multiple-choice Multi-dimension 0-1 Knapsack Problem (MMKP), a variation of the classical 0-1 Knapsack Problem. We also present a design for an optimal RAC system based on the Utility Model. This method uses the MMKP formulation of the optimal RAC problem to provide an integrated solution of the session routing, admission control and resource allocation problems. Our experiments show that optimal RAC using the MMKP formulation (OptRAC) would provide 7-16% more revenue than the revenue provided by a traditional RAC system (TradRAC).

FPGA-Based Reconfigurable Hardware for Compute Intensive Data Mining Applications

Advances in distributed system technology have enabled new computation paradigms such as Grid, Cloud, and Internet computing. Due to the logical and physical organization of these paradigms, portable and embedded computing devices are being developed and naturally becoming an integral part of these systems. In addition to stringent area and power requirements, design constraints such as time-to-market and competitive margin pose serious challenges to embedded hardware designers. One of the most promising avenues to overcome these challenges is reconfigurable hardware. In this work, FPGA-based reconfigurable hardware is examined. As a case study, Principal Component Analysis (PCA), the classical technique to reduce the dimensionality of data and to extract dominant features, is designed and implemented as hardware on FPGA to be reconfigured dynamically during execution. Using part of a handwriting analysis application together with a benchmark dataset, experiments are performed to evaluate the feasibility, efficiency, and flexibility of reconfigurable hardware.

Keysurf: a character controlled browser for people with physical disabilities

For many users with a physical or motor disability, using a computer mouse or other pointing device to navigate the web is cumbersome or impossible due to problems with pointing accuracy. At the same time, web accessibility using a keyboard in major browsers is rudimentary, requiring many key presses to select links or other elements. We introduce KeySurf, a character controlled web navigation system which addresses this situation by presenting an interface which allows a user to activate any web page element with only two or three keystrokes. Through an implementation of a user-centric incremental search algorithm, elements are matched according to user expectation as characters are entered into the interface. We show how our interface can be integrated with a speech recognition input, as well as with specialized on-screen keyboards for people with disabilities. Using the users browsing history, we improve the efficiency of the selection process and find potentially interesting page links for the user within the current web page. We present the results from a pilot study evaluating the performance of various components of our system.