14948724
Joint software research between industry and academia
A model for industry-sponsored academic software research tha helps the sponsor gain tangible results quickly but respects the university's research mission is presented. Central to the model is joint effort to achieve a win-win situation for all participants. The key is the relationship between the university's principal investigator and the company's visiting scholar. The principal investigator initiates research contracts and is responsible for research results but, because he or she is an academic, may not have an industrial perspective. The company dispatches a technical representative, called the visiting scholar, to participate directly in the daily research. A research structure, relations with the sponsoring company, issues regarding environmental compatibility and funding amount and duration, and a reporting structure are all spelled out in the model. Legal recommendations are made with respect to confidentiality, copyrights and patents, export controls, and other issues. Other considerations that arise when writing a research contract are discussed.<<ETX>>
30575380
Modeling a real-time multitasking system in a timed PQ net
A system is described that integrates timed Petri nets and queueing networks to model complex, real-time systems. It includes a graphical modeling tool, called TPQN, a textual specification language, called TPQL, and a simulator, called TPQS. TPQN's capabilities are illustrated by a performance analysis of a real-time, multitasking scheduler that had been previously implemented on top of SunOS on a Sun-3 workstation. A simulation package has been developed for TPQN that allows the behavior of various complicated systems under a designated queueing network topology to be studied before the system is implemented.<<ETX>>
35042753
A Binary Single-Key-Lock System for Access Control
A binary coding method was invented and has been applied to the single-key-lock (SKL) system which achieves access control by associating with each accesser only one key and with each resource only one lock. The new system is called the binary single-key-lock (BSKL) system. In both the SKL and BSKL systems, through operations on the single-key-lock pair, the control information can be revealed. On the basis of the new binary coding method, and because binary operations are much faster, better performance for such an access control system can be achieved. The increased extensibility of the modification is also discussed. >
9167410
Computing curricula 2001 how will it work for you?
In the fall of 1998, the ACM Education Board and the Educational Activities Board of the IEEE Computer Society appointed representatives to a joint task force to prepare Computing Curricula 2001 (CC2001), the next installment in a series of reports on the undergraduate computer science curriculum that began in 1968 and was then updated in 1978 and 1991. Interim reports on the initial planning of the curriculum were presented at the SIGCSE symposium and the IEEE Frontiers in Education Conference in both 1999 and 2000. The CC2001 Task Force released its first draft report at the 2000 SIGCSE conference and plans to release its penultimate draft at SIGCSE 2001. The purpose of this session is to describe how we expect the recommendations of the report to apply in practice. The panelists represent a range of institutions and can therefore speak to the questions that audience members from similar institutions might have.
2457108
An object-oriented real-time distributed simulation of cellular phone switching system
The cellular phone network is a distributed system which is composed of three kinds of subsystems, a mobile phone unit, a base site station and a MSC (mobile switching center). A class of cellular phone switching systems, was chosen as the system to be studied. SUN workstations and the UNIX operating system with X windows have been employed as the core of the development environment. The object-oriented (OO) paradigm and C++ were chosen to develop the simulation. UICCELL was developed as an object-oriented system for cellular phone switching real-time multitasking simulation. UICCELL has been fully implemented and is currently running on an Ethernet LAN. A central monitor is created on the screen to manipulate and monitor the simulator. The graphical user interface displays the configuration of UICCELL and the status of processors, channels, etc. The current implementation contains 60 classes and about 20,000 lines of C++ code.<<ETX>>
9710130
A specification language for real-time distributed systems
The authors introduce a design specification method, extended modified Petri nets (EMPN), and its description language (EMPNDL). The specification is based on a stochastic Petri-net model and is suitable for modeling real-time distributed systems. The syntax of the language is formally described in BNF grammar while the semantics is based on that for stochastic Petric nets. In addition to the modeling capability of EMPN and EMPNDL, methods for verification and validation of such systems are also discussed. EMPN and EMPNDL have been extensively used to the specification of a prototype switching system, UICPBX. Based on the presented formulation, verification and validation of UICPBX can be automated to a great extent.<<ETX>>
30291393
Formalization of computer supported cooperative work applications
From its first appearance in 1984, Computer Supported Cooperative Work (CSCW) has attracted a lot of research attention in distributed systems. Over the past decade, the CSCW community has developed a number of experimental systems and commercial products to support collaboration. However, much of the reported work is highly application-specific. There generally lacks a sound infrastructure to support the development of a wide variety of CSCW applications. It is essential to formalize the collaboration concepts, model the cooperative and communicative activities, erect CSCW-oriented architectures, and construct a flexible and extendable development environment for building CSCW applications.
9268321
Online medical teaching case database
Case-based teaching allows for the study of medicine through records of patient encounters. These cases, used for teaching purposes, are variably collected by clinicians as hard copies of patient files and radiology films. Currently, a single repository of thorough, multi-disciplinary, medical teaching cases that can be uniformly accessed, shared, and searched comprehensively by all medical professionals does not exist. An Internet accessible database (iCORD) that focuses on graphical, audio-visual information along with text has been created. Users may create their own teaching case records to organize their files and share them with others. Case submissions are executed through a non-platform-specific application securely connected to the iCORD database. This submission tool and connector module, was developed using Java and XML-related technologies. The data storage medium, which is an extensible SQL database primarily used for storing patient case information, is exposed using IIS 5.0 and XML-based transformation tools to allow dynamic content delivery to PC's and handheld devices. Usage statistics, distributable teaching files, and user-centric information, which are compiled in the iCORD database, allow development of useful case search algorithms. The prototype database of 400 otolaryngology clinical cases is fully searchable using Boolean logic by parameters including age, gender, diagnosis, medical history, clinical keywords, pathology keywords, and more. The database can be used as a teaching tool during conferences and as a case authoring tool for physicians.
18643244
An Empirical Performance Study on PSIM
It is well known that errors caught in the early stages of system development life cycle greatly helped reduce the expense for later error fixing and mitigate risks and complications. Performance analysis is one of the methods to ensure satisfactory system performance that can avoid redesign and patch in the later stage of system development when performance problems emerge. Much work has been done to address such concerns collectively known as the 'performance engineering' problem. However, a comprehensive method is still needed to provide an end-to-end support for performance evaluation on software architecture design. Automated tools to support the method must be developed, and its validation must be carefully planned and conducted. In response to this need, we propose our approach, PSIM (performance simulation and modeling). PSIM is a performance simulation and modeling tool that integrated performance properties into software architecture specifications expressed in several major UML diagrams. PSIM models can be transformed into Colored GSPN (colored generalized stochastic Petri nets) via an automated tool. As a result, the Colored GSPN models can be simulated to perform model-based performance evaluation. In this paper PSIM is first briefly reviewed and illustrated through modeling a web-based electronic conferencing system, called M-Net, to derive performance metrics. We then conduct runtime performance testing to the implementation of M-Net and compare the simulation results against the runtime testing data. PSIM is shown to be effective in predicting system performance and in identifying system performance bottlenecks through this experimentation.
7769541
A Net Practice for Software Project Management
Technical and managerial complexity increasingly overwhelm project managers. To rein in that complexity, the authors propose PM-Net, a model that captures the concurrent, iterative, and evolutionary nature of software development. It adopts the basic concepts of Petri nets, graphical models of information flow, with extensions to represent both decisions and artifacts.
10778870
An empirical performance study for validating a performance analysis approach: PSIM
Performance analysis gains more attention in recent years by researchers who focus their study on the early software development stages to mitigate the risk of redesign as problems emerge later. Previously we proposed PSIM (a performance simulation and modeling tool) that integrated performance properties into software architecture specifications expressed in several major UML diagrams. PSIM models can be transformed into colored GSPN and the colored GSPN models can then be simulated to perform model-based performance evaluation. In this paper we briefly review the PSIM approach and apply it to model a Web-based conferencing system, called M-Net, to derive performance metrics. We then conduct runtime performance testing to the implementation of M-Net and compare the simulation data to runtime testing data. The comparison results show the effectiveness of the PSIM method in predicting system performance and identifying system performance bottlenecks.