43825190
Temporal Relations and Synchronization Agents
Temporal relationships, inevitable among distributed multimedia objects, require synchronization of multiple data streams in time. We propose using synchronization agents as "smart" distributed objects to deal with scheduling, integrating, and synchronizing distributed multimedia streams. A formal specification model, interoperable Petri nets, describes the agents' behavior and captures the temporal semantics existing among distributed multimedia objects.
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.
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>>
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>>
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>>
33039704
A circular skip-cluster scheme to support video-on-demand services
Abstract. The major drawback of the existing cluster placement scheme is the long response time caused by admission control if the number of clusters and the number of users are large. A circular skip-cluster placement scheme is proposed to reduce the size of the data buffer as well as the system response time. Furthermore, the popularity of each video is different in the real world. We propose a new popularity-based data allocation scheme to allocate data units within a cluster such that the corresponding data units of these popular videos are stored in those cylinders at one end of each cluster. Due to a higher spatial locality within these hot cylinders, some data units requested by the users are stored in the same cylinder such that one seek operation, one rotation, and one transfer operation are required to retrieve these data units. Therefore, the time required to retrieve data for these requests can be reduced, thus also reducing the system response time. Based on our results, the buffer size and the system response time can be reduced by half or more. These findings are essential for constructing video-on-demand systems that provide satisfactory performance.
8941164
Supporting agent-based distributed software development through modeling and simulation
In today's software engineering environment, it is becoming increasingly commonplace for team members and stakeholders to be distributed in multiple locations and time zones. Under these circumstances, the coordination of software development activities becomes increasingly more complex. One solution uses mobile agent-based tools to support collaborative software engineering tasks, such as requirements management. Despite the fact that development and validation of such tools would be facilitated by the use of modeling and simulation, very little work relating formal methods to agent-based system development has been performed. This paper therefore presents a hierarchical colored Petri Net (CPN) model as a formal framework for agent-based distributed software development, and demonstrates its usefulness by applying the framework to the development of a requirements management system.
15018569
Categorical data visualization and clustering using subjective factors
A common issue in cluster analysis is that there is no single correct answer to the number of clusters, since cluster analysis involves human subjective judgement. Interactive visualization is one of the methods where users can decide a proper clustering parameters. In this paper, a new clustering approach called CDCS (Categorical Data Clustering with Subjective factors) is introduced, where a visualization tool for clustered categorical data is developed such that the result of adjusting parameters is instantly reflected. The experiment shows that CDCS generates high quality clusters compared to other typical algorithms.
12945067
A Fast Search Algorithm for Vector Quantization
285,641. British Celanese, Ltd., and Olpin, H. C. Feb. 9, 1927. Samples furnished. Anthraquinone derivatives.-Sulphuric esters of anthraquinonylamino alcohols, which are dyestuffs for organic substitution products of cellulose, e.g. cellulose esters and ethers, and for animal fibres, are made by treating the corresponding alcohols with sulphuric acid or oleum; or by the action of sulphuric esters of aminoalcohols on leuco oxyanthraquinones, e.g. the leuco compounds of 1-oxy-, 1 : 4-dioxy-, 1 : 4 : 5- trioxy or 1 : 4 : 5 : 8-tetraoxy-anthraquinone, followed by oxidation of the leuco body; or by replacement of chlor, nitro, methoxy &c. groups by treatment with sulphuric esters of aminoalcohols, e.g. #-aminoethyl alcohol. The anthraquinonylamino alcohols, for treatment with sulphuric acid or oleum, may be obtained by treating amino or mono-substituted amino derivatives of anthraquinone or substituted anthraquinones with halohydrins, e.g. ethylene, propylene or glyceryl chlorhydrins, epichlorhydrin, or chlorbutylene glycol, or with alkylene oxides, e.g. ethylene or propylene oxide, or with oxyaldehydes or ketones, or by replacement of chlor, nitro, hydroxy, methoxy &c. groups by treatment with an amino alcohol. The sulphuric esters of 1-#-oxyethylamino-, 1-#-oxyethylamino-2 (and 4)- methyl-, 1-#-oxyethylamino-4-oxy (and amino)-, 1-#-oxyethylamino-2-brom-4-amino-, and 1 : 4- and 1: 5-di-#-oxyethylamino-anthraquinones are specified.
31867607
Reconfigurable Web Wrapper Agents
Web wrapper agents exploit online Web data sources, facilitating information integration and reuse. With the DeepSpot Agent Toolbox, users can automate virtually all types of Web browsing sessions simply by browsing the target Web sites.