Pub Date : 1992-04-01DOI: 10.1109/PCCC.1992.200553
S. Urban, K. Chalmers
An investigation of the view update problem for object-oriented views is presented. Views are formed using an object algebra that provides a set-oriented approach to the retrieval of objects. A view is defined to include an intension and an extension, where the extension of a view is updated by modifying objects in the scope of the query intension. The rich set of semantic constraints inherent in an object-oriented data model, enhanced with semantic modeling concepts, helps to make the effects of view updates explicit. The contribution of this research is the development of an approach for analyzing semantic constraints associated with the view intension to (1) identify alternative view update translations and (2) identify potential update side effects. The approach can be used to help in the design of view update operations that correctly reflect the intended semantics of the update.<>
{"title":"An investigation of the view update problem for object-oriented views","authors":"S. Urban, K. Chalmers","doi":"10.1109/PCCC.1992.200553","DOIUrl":"https://doi.org/10.1109/PCCC.1992.200553","url":null,"abstract":"An investigation of the view update problem for object-oriented views is presented. Views are formed using an object algebra that provides a set-oriented approach to the retrieval of objects. A view is defined to include an intension and an extension, where the extension of a view is updated by modifying objects in the scope of the query intension. The rich set of semantic constraints inherent in an object-oriented data model, enhanced with semantic modeling concepts, helps to make the effects of view updates explicit. The contribution of this research is the development of an approach for analyzing semantic constraints associated with the view intension to (1) identify alternative view update translations and (2) identify potential update side effects. The approach can be used to help in the design of view update operations that correctly reflect the intended semantics of the update.<<ETX>>","PeriodicalId":250212,"journal":{"name":"Eleventh Annual International Phoenix Conference on Computers and Communication [1992 Conference Proceedings]","volume":"814 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133181957","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-04-01DOI: 10.1109/PCCC.1992.200600
R. Curtis, S. Scarfone
XFace is a tool for displaying on X devices multivariate data as graphical images called Flury-Riedwyl faces. The tool allows the user to map variables to facial features such as eye size, slant, and position; pupil size and position; eyebrow curvature, density, and position; hair color and line; mouth curvature and size; face line; and nose shape. Symmetric faces support up to 17 variables and asymmetric faces support up to 34 variables. The menu-driven tool was developed in C and uses X Windows with Athena Widgets for portability. The system was developed to display software metrics. A manager may map each module's metrics to a face so that a quick scan determines modules with characteristics that vary from the project norm and which may require attention.<>
{"title":"XFace, an X tool for presenting multivariate data, and its use with software metrics","authors":"R. Curtis, S. Scarfone","doi":"10.1109/PCCC.1992.200600","DOIUrl":"https://doi.org/10.1109/PCCC.1992.200600","url":null,"abstract":"XFace is a tool for displaying on X devices multivariate data as graphical images called Flury-Riedwyl faces. The tool allows the user to map variables to facial features such as eye size, slant, and position; pupil size and position; eyebrow curvature, density, and position; hair color and line; mouth curvature and size; face line; and nose shape. Symmetric faces support up to 17 variables and asymmetric faces support up to 34 variables. The menu-driven tool was developed in C and uses X Windows with Athena Widgets for portability. The system was developed to display software metrics. A manager may map each module's metrics to a face so that a quick scan determines modules with characteristics that vary from the project norm and which may require attention.<<ETX>>","PeriodicalId":250212,"journal":{"name":"Eleventh Annual International Phoenix Conference on Computers and Communication [1992 Conference Proceedings]","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130387461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-04-01DOI: 10.1109/PCCC.1992.200574
Z. Wang, J. Crowcroft
A new approach for deriving quantitative information for rate-based congestion schemes is presented. Using the fluid model, it is shown that the bottleneck capacity can be estimated from round trip delay when the sender is increasing its traffic rate linearly. The exact solution for a time-dependent M(t)/M(t)/1 queue verifies that the approximation is accurate when the traffic load is high. The analytical results were verified with simulation experiments, and the practical issues in applying the estimation techniques in congestion control schemes are discussed.<>
{"title":"A fluid model approximation to quantitative information feedback in congestion control","authors":"Z. Wang, J. Crowcroft","doi":"10.1109/PCCC.1992.200574","DOIUrl":"https://doi.org/10.1109/PCCC.1992.200574","url":null,"abstract":"A new approach for deriving quantitative information for rate-based congestion schemes is presented. Using the fluid model, it is shown that the bottleneck capacity can be estimated from round trip delay when the sender is increasing its traffic rate linearly. The exact solution for a time-dependent M(t)/M(t)/1 queue verifies that the approximation is accurate when the traffic load is high. The analytical results were verified with simulation experiments, and the practical issues in applying the estimation techniques in congestion control schemes are discussed.<<ETX>>","PeriodicalId":250212,"journal":{"name":"Eleventh Annual International Phoenix Conference on Computers and Communication [1992 Conference Proceedings]","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115506426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-04-01DOI: 10.1109/PCCC.1992.200555
A. del Bimbo, P. Nesi
A blackboard-based framework is presented for concurrent object recognition in the presence of a large model database. A new object model is defined with a knowledge organization with two-object hierarchies. Concurrency has been introduced in order to provide a separate execution thread for each scheduled model. The system performs recognition by comparing graphical entities with models that are stored in an object-oriented database. Results are presented in terms of performance figures on a multiprocessor architecture.<>
{"title":"Blackboard-based concurrent object recognition using an object-oriented database","authors":"A. del Bimbo, P. Nesi","doi":"10.1109/PCCC.1992.200555","DOIUrl":"https://doi.org/10.1109/PCCC.1992.200555","url":null,"abstract":"A blackboard-based framework is presented for concurrent object recognition in the presence of a large model database. A new object model is defined with a knowledge organization with two-object hierarchies. Concurrency has been introduced in order to provide a separate execution thread for each scheduled model. The system performs recognition by comparing graphical entities with models that are stored in an object-oriented database. Results are presented in terms of performance figures on a multiprocessor architecture.<<ETX>>","PeriodicalId":250212,"journal":{"name":"Eleventh Annual International Phoenix Conference on Computers and Communication [1992 Conference Proceedings]","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122883954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-04-01DOI: 10.1109/PCCC.1992.200527
L. Shen, Y.-H. Lee
The authors propose a dynamic priority assignment scheme which is able to make the best use of the multiple priority mechanism and achieve significant system performance for real-time communications. First, they briefly introduce the distributed queue dual bus (DQDB) standard and point out some problems for real-time communications. A dynamic system model is proposed and some design strategies for the dynamic priority scheme are discussed. An efficient assignment algorithm based on the analysis of the mean media access delay is presented. Simulation results under various situations validated the model analysis and showed the significant performance improvement, compared to conventional media access control (MAC) protocols, for real-time communications.<>
{"title":"Dynamic priority assignment scheme for real-time communications in DQDB networks","authors":"L. Shen, Y.-H. Lee","doi":"10.1109/PCCC.1992.200527","DOIUrl":"https://doi.org/10.1109/PCCC.1992.200527","url":null,"abstract":"The authors propose a dynamic priority assignment scheme which is able to make the best use of the multiple priority mechanism and achieve significant system performance for real-time communications. First, they briefly introduce the distributed queue dual bus (DQDB) standard and point out some problems for real-time communications. A dynamic system model is proposed and some design strategies for the dynamic priority scheme are discussed. An efficient assignment algorithm based on the analysis of the mean media access delay is presented. Simulation results under various situations validated the model analysis and showed the significant performance improvement, compared to conventional media access control (MAC) protocols, for real-time communications.<<ETX>>","PeriodicalId":250212,"journal":{"name":"Eleventh Annual International Phoenix Conference on Computers and Communication [1992 Conference Proceedings]","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129567845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-04-01DOI: 10.1109/PCCC.1992.200607
M. Ancona, A. Bartolozzi, M. Paci, S. Provvedi
A method for optimizing LR(k) tables is presented. This method extends the algorithms of phi -inaccessible tables and error postponement for LR(k) tables defined by A. V. Aho and J. D. Ullman (1972, 1973) to a new kind of parsing tables, called reduced tables. Reduced tables are more convenient than canonical tables for all classes of LR grammars. For example, reduced tables can be effectively used to create full LR parsers for programming languages like Pascal, C, Oberon, and Eiffel. Experiments with some important programming languages show rates of optimization of the order of 70% of the eliminated tables and of 50% of nonerror deleted entries. Such results have been obtained with the grammars of programming languages like Ada, Pascal, C, Oberon, and Modula-2.<>
{"title":"Practical optimizations of LR(k) parsing tables","authors":"M. Ancona, A. Bartolozzi, M. Paci, S. Provvedi","doi":"10.1109/PCCC.1992.200607","DOIUrl":"https://doi.org/10.1109/PCCC.1992.200607","url":null,"abstract":"A method for optimizing LR(k) tables is presented. This method extends the algorithms of phi -inaccessible tables and error postponement for LR(k) tables defined by A. V. Aho and J. D. Ullman (1972, 1973) to a new kind of parsing tables, called reduced tables. Reduced tables are more convenient than canonical tables for all classes of LR grammars. For example, reduced tables can be effectively used to create full LR parsers for programming languages like Pascal, C, Oberon, and Eiffel. Experiments with some important programming languages show rates of optimization of the order of 70% of the eliminated tables and of 50% of nonerror deleted entries. Such results have been obtained with the grammars of programming languages like Ada, Pascal, C, Oberon, and Modula-2.<<ETX>>","PeriodicalId":250212,"journal":{"name":"Eleventh Annual International Phoenix Conference on Computers and Communication [1992 Conference Proceedings]","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131353572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-04-01DOI: 10.1109/PCCC.1992.200609
J. Fonseka
Baseband pulse shaping is proposed to improve the performance of M-ary frequency shift keying (FSK) with limiter discriminator detection in a satellite mobile channel. Numerical results obtained for binary, quaternary and octonary signals, indicate that pulse shaped signals perform significantly better than FSK signals. The error rate floor in presence of a Doppler shift is also analyzed. Numerical results indicate that the error rate floor of the pulse shaped signals is significantly lower than that of FSK signals.<>
{"title":"An improved narrow-band M-ary FSK technique in satellite mobile systems","authors":"J. Fonseka","doi":"10.1109/PCCC.1992.200609","DOIUrl":"https://doi.org/10.1109/PCCC.1992.200609","url":null,"abstract":"Baseband pulse shaping is proposed to improve the performance of M-ary frequency shift keying (FSK) with limiter discriminator detection in a satellite mobile channel. Numerical results obtained for binary, quaternary and octonary signals, indicate that pulse shaped signals perform significantly better than FSK signals. The error rate floor in presence of a Doppler shift is also analyzed. Numerical results indicate that the error rate floor of the pulse shaped signals is significantly lower than that of FSK signals.<<ETX>>","PeriodicalId":250212,"journal":{"name":"Eleventh Annual International Phoenix Conference on Computers and Communication [1992 Conference Proceedings]","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133744191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-04-01DOI: 10.1109/PCCC.1992.200531
S. Sur, P. Srimani
The authors propose a new family of interconnection topology that can be used to design communication architectures for distributed systems with an arbitrary number of computing nodes. The design is based on a novel generalization of the well-known hypercube graphs. The proposed topology is shown to be incrementally extensible in steps of 1 and to be optimally fault tolerant, and its diameter is logarithmic in the number of nodes. For any given number of nodes, the difference of the maximum and the minimum degree of a node in the graph is >
{"title":"Incrementally extensible hypercube (IEH) graphs","authors":"S. Sur, P. Srimani","doi":"10.1109/PCCC.1992.200531","DOIUrl":"https://doi.org/10.1109/PCCC.1992.200531","url":null,"abstract":"The authors propose a new family of interconnection topology that can be used to design communication architectures for distributed systems with an arbitrary number of computing nodes. The design is based on a novel generalization of the well-known hypercube graphs. The proposed topology is shown to be incrementally extensible in steps of 1 and to be optimally fault tolerant, and its diameter is logarithmic in the number of nodes. For any given number of nodes, the difference of the maximum and the minimum degree of a node in the graph is <or=1, i.e. the graph is almost regular.<<ETX>>","PeriodicalId":250212,"journal":{"name":"Eleventh Annual International Phoenix Conference on Computers and Communication [1992 Conference Proceedings]","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132780983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-04-01DOI: 10.1109/PCCC.1992.200571
P. Charette, R. Martinez, J. Tao
A project was conceived to research and develop gateway systems which will help incorporate new LANs into the campus internet. The research presented is from the first stage of this project, which involved the design, development, implementation and testing of a generic gateway prototype to incorporate a selected campus LAN into the campus internet. The candidate LAN selected was the University of Arizona Sytek broadband network, which includes the Sytek LocalNet 20 and System 2000 networks. How this connection-oriented LAN was incorporated into an IP internet using a router is outlined.<>
{"title":"The Sytek to Ethernet IP-router: an example of how to incorporate a connection-oriented LAN into an internet","authors":"P. Charette, R. Martinez, J. Tao","doi":"10.1109/PCCC.1992.200571","DOIUrl":"https://doi.org/10.1109/PCCC.1992.200571","url":null,"abstract":"A project was conceived to research and develop gateway systems which will help incorporate new LANs into the campus internet. The research presented is from the first stage of this project, which involved the design, development, implementation and testing of a generic gateway prototype to incorporate a selected campus LAN into the campus internet. The candidate LAN selected was the University of Arizona Sytek broadband network, which includes the Sytek LocalNet 20 and System 2000 networks. How this connection-oriented LAN was incorporated into an IP internet using a router is outlined.<<ETX>>","PeriodicalId":250212,"journal":{"name":"Eleventh Annual International Phoenix Conference on Computers and Communication [1992 Conference Proceedings]","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128316753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1992-04-01DOI: 10.1109/PCCC.1992.200595
J. Merlo, C.H. Zanvettor
The authors address the problem of finding the optimal configuration for a distributed application and also determine what database access approach is best suited to each remote database function request. In addition, the formulation developed allows the introduction of constraints that set priorities for the expected response time of each process component of the distributed application. A methodology is described for designing distributed applications accessing remote data in two approaches: remote request shipping and remote transaction shipping. The methodology leads to a final nonlinear programming model, after heuristic steps that continuously reduce the complexity of the problem context. The methodology is applied in a case example for an IBM CICS transaction manager.<>
{"title":"Computer communication modeling for a multisite distributed application design methodology","authors":"J. Merlo, C.H. Zanvettor","doi":"10.1109/PCCC.1992.200595","DOIUrl":"https://doi.org/10.1109/PCCC.1992.200595","url":null,"abstract":"The authors address the problem of finding the optimal configuration for a distributed application and also determine what database access approach is best suited to each remote database function request. In addition, the formulation developed allows the introduction of constraints that set priorities for the expected response time of each process component of the distributed application. A methodology is described for designing distributed applications accessing remote data in two approaches: remote request shipping and remote transaction shipping. The methodology leads to a final nonlinear programming model, after heuristic steps that continuously reduce the complexity of the problem context. The methodology is applied in a case example for an IBM CICS transaction manager.<<ETX>>","PeriodicalId":250212,"journal":{"name":"Eleventh Annual International Phoenix Conference on Computers and Communication [1992 Conference Proceedings]","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1992-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123891092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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