Pub Date : 2001-04-16DOI: 10.1109/CDCS.2001.918723
Y. Shyu, Peng-Wen Chen
Traditional higher education has long been criticized for its high cost and low quality. With the advances of multimedia and networks, many educators are trying to apply these new techniques in education. They are looking for new models and environments for future education and are hoping that new results will also solve the problems mentioned above. Distance learning seems to be an appealing alternative. However, this kind of new approach does not yet seem to have emerged as a good solution. Despite this result, distance learning does provide a new way to solve learners' spatial and temporal problems. Since distance learning is itself a very rich research subject, issues of high cost and low quality are no longer of major concern for most research. In this paper, we are interested in the low-quality problem occurring in higher education, especially in programming teaching/learning. We discuss those factors that seriously degrade learning qualities. Then, we try to come up with a better solution. A programming language laboratory (PLL) system is designed and implemented. The salient features of this system are that: (1) the content of the learner's self-practice is well-designed and organized by the instructor. Thus, the learning curve is very smooth and the learning is very efficient. (2) The instructor is able to involve himself in the learner's learning process in a non-passive way.
{"title":"PLL: a programming languages lab system","authors":"Y. Shyu, Peng-Wen Chen","doi":"10.1109/CDCS.2001.918723","DOIUrl":"https://doi.org/10.1109/CDCS.2001.918723","url":null,"abstract":"Traditional higher education has long been criticized for its high cost and low quality. With the advances of multimedia and networks, many educators are trying to apply these new techniques in education. They are looking for new models and environments for future education and are hoping that new results will also solve the problems mentioned above. Distance learning seems to be an appealing alternative. However, this kind of new approach does not yet seem to have emerged as a good solution. Despite this result, distance learning does provide a new way to solve learners' spatial and temporal problems. Since distance learning is itself a very rich research subject, issues of high cost and low quality are no longer of major concern for most research. In this paper, we are interested in the low-quality problem occurring in higher education, especially in programming teaching/learning. We discuss those factors that seriously degrade learning qualities. Then, we try to come up with a better solution. A programming language laboratory (PLL) system is designed and implemented. The salient features of this system are that: (1) the content of the learner's self-practice is well-designed and organized by the instructor. Thus, the learning curve is very smooth and the learning is very efficient. (2) The instructor is able to involve himself in the learner's learning process in a non-passive way.","PeriodicalId":273489,"journal":{"name":"Proceedings 21st International Conference on Distributed Computing Systems Workshops","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115516549","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 : 2001-04-16DOI: 10.1109/CDCS.2001.918692
M. Pinto, M. Amor, L. Fuentes, J. M. Troya
Nowadays, the interest in collaborative environments has increased considerably, probably due to current technological advances, especially in Internet computing. However, the lack of a standard reference architecture for the development of these systems makes the development of useful collaborative environments, that can be used in real work, difficult. Our goal is the development of a framework for the construction of collaborative virtual environments. We consider aspect-oriented programming to be very suitable for both the design and implementation of these systems. Thus, we present an aspect-oriented approach for the development of collaborative virtual environments.
{"title":"Collaborative virtual environment development: an aspect-oriented approach","authors":"M. Pinto, M. Amor, L. Fuentes, J. M. Troya","doi":"10.1109/CDCS.2001.918692","DOIUrl":"https://doi.org/10.1109/CDCS.2001.918692","url":null,"abstract":"Nowadays, the interest in collaborative environments has increased considerably, probably due to current technological advances, especially in Internet computing. However, the lack of a standard reference architecture for the development of these systems makes the development of useful collaborative environments, that can be used in real work, difficult. Our goal is the development of a framework for the construction of collaborative virtual environments. We consider aspect-oriented programming to be very suitable for both the design and implementation of these systems. Thus, we present an aspect-oriented approach for the development of collaborative virtual environments.","PeriodicalId":273489,"journal":{"name":"Proceedings 21st International Conference on Distributed Computing Systems Workshops","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125660881","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 : 2001-04-16DOI: 10.1109/CDCS.2001.918728
N. Sato, M. Uehara, Y. Sakai, H. Mori
Information retrieval is frequently used for the Internet. However, we face the problem that the update intervals of conventional search engines are too long. It is difficult for conventional search engines to make their intervals short because they are based on a centralized architecture. So, we proposed the Cooperative Search Engine (CSE), which is based on a distributed architecture. CSE can realize the shortening of the update interval. In CSE, a large search engine is constructed from multiple local meta search engines that cooperate with each other. CSE can accomplish correct ranking in a distributed fashion because each local meta search engine hides the difference between its local search engine and the others. The article discusses the design and experimental evaluations of CSE.
{"title":"Distributed information retrieval by using cooperative meta search engines","authors":"N. Sato, M. Uehara, Y. Sakai, H. Mori","doi":"10.1109/CDCS.2001.918728","DOIUrl":"https://doi.org/10.1109/CDCS.2001.918728","url":null,"abstract":"Information retrieval is frequently used for the Internet. However, we face the problem that the update intervals of conventional search engines are too long. It is difficult for conventional search engines to make their intervals short because they are based on a centralized architecture. So, we proposed the Cooperative Search Engine (CSE), which is based on a distributed architecture. CSE can realize the shortening of the update interval. In CSE, a large search engine is constructed from multiple local meta search engines that cooperate with each other. CSE can accomplish correct ranking in a distributed fashion because each local meta search engine hides the difference between its local search engine and the others. The article discusses the design and experimental evaluations of CSE.","PeriodicalId":273489,"journal":{"name":"Proceedings 21st International Conference on Distributed Computing Systems Workshops","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125859899","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 : 2001-04-16DOI: 10.1109/CDCS.2001.918730
K. Shimamura, Katsuya Tanaka, M. Takizawa
In distributed applications like teleconferences, a group of multiple processes cooperate, where messages exchanged among the processes are required to be causally delivered. The processes exchange types of multimedia objects. The multimedia objects are longer than traditional messages and are structured. The authors discuss novel types of causally precedent relations among multimedia objects transmitted in the network. They discuss a protocol to causally deliver multimedia objects in a group of processes. The authors also show the evaluation of the protocol.
{"title":"Group communication of multimedia objects","authors":"K. Shimamura, Katsuya Tanaka, M. Takizawa","doi":"10.1109/CDCS.2001.918730","DOIUrl":"https://doi.org/10.1109/CDCS.2001.918730","url":null,"abstract":"In distributed applications like teleconferences, a group of multiple processes cooperate, where messages exchanged among the processes are required to be causally delivered. The processes exchange types of multimedia objects. The multimedia objects are longer than traditional messages and are structured. The authors discuss novel types of causally precedent relations among multimedia objects transmitted in the network. They discuss a protocol to causally deliver multimedia objects in a group of processes. The authors also show the evaluation of the protocol.","PeriodicalId":273489,"journal":{"name":"Proceedings 21st International Conference on Distributed Computing Systems Workshops","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115116093","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 : 2001-04-12DOI: 10.1109/CDCS.2001.918747
Vlad Korolev, A. Joshi
We propose a lightweight scheme for negotiating client capabilities in the context of end-end content adaptation for wireless Web access. Our method is much less complex then W3C's proposed CC/PP framework. We suggest that for the purposes of content negotiation, all (mobile) clients could be grouped into a few relatively large categories. With this assumption, we simplify the CC/PP protocol and implement it as an Apache module. The paper describes the simple CC/PP protocol, issues related to its implementation, and performance measurements.
{"title":"An end-end approach to wireless Web access","authors":"Vlad Korolev, A. Joshi","doi":"10.1109/CDCS.2001.918747","DOIUrl":"https://doi.org/10.1109/CDCS.2001.918747","url":null,"abstract":"We propose a lightweight scheme for negotiating client capabilities in the context of end-end content adaptation for wireless Web access. Our method is much less complex then W3C's proposed CC/PP framework. We suggest that for the purposes of content negotiation, all (mobile) clients could be grouped into a few relatively large categories. With this assumption, we simplify the CC/PP protocol and implement it as an Apache module. The paper describes the simple CC/PP protocol, issues related to its implementation, and performance measurements.","PeriodicalId":273489,"journal":{"name":"Proceedings 21st International Conference on Distributed Computing Systems Workshops","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122369284","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 : 2001-04-01DOI: 10.1109/CDCS.2001.918701
P. Sties, W. Kellerer
Attractive services will be the crucial factor in the future competition of providers in the telecommunications market. While system heterogeneity and service convergence complicate the service provisioning process, there are still no common models to support early service analysis. We present an implementation and network platform independent model for service description. It consists of abstract descriptions for endpoints, communication channels and communication relations. This model can support all service development phases including requirements analysis and service architecture design. We focus on the requirement phase where a tool supported analysis could facilitate early technical and economical decisions.
{"title":"A generic and implementation independent service description model","authors":"P. Sties, W. Kellerer","doi":"10.1109/CDCS.2001.918701","DOIUrl":"https://doi.org/10.1109/CDCS.2001.918701","url":null,"abstract":"Attractive services will be the crucial factor in the future competition of providers in the telecommunications market. While system heterogeneity and service convergence complicate the service provisioning process, there are still no common models to support early service analysis. We present an implementation and network platform independent model for service description. It consists of abstract descriptions for endpoints, communication channels and communication relations. This model can support all service development phases including requirements analysis and service architecture design. We focus on the requirement phase where a tool supported analysis could facilitate early technical and economical decisions.","PeriodicalId":273489,"journal":{"name":"Proceedings 21st International Conference on Distributed Computing Systems Workshops","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133367895","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 : 2001-04-01DOI: 10.1109/CDCS.2001.918740
M. Marina, Samir R Das
On-demand routing protocols for mobile ad hoc networks utilize route caching in different forms in order to reduce the routing overheads as well as to improve the route discovery latency. For route caches to be effective, they need to adapt to frequent topology changes. Using an on-demand protocol called Dynamic Source Routing (DSR), we study the problem of keeping the caches up-to-date in dynamic ad hoc networks. Previous studies have shown that cache staleness in DSR can significantly degrade performance. We present and evaluate three techniques to improve cache correctness in DSR namely wider error notification, route expiry mechanism with adaptive timeout selection and the use of negative caches. Simulation results show that the combination of the proposed techniques not only result in substantial improvement of both application and cache performance but also reduce the overheads.
{"title":"Performance of route caching strategies in Dynamic Source Routing","authors":"M. Marina, Samir R Das","doi":"10.1109/CDCS.2001.918740","DOIUrl":"https://doi.org/10.1109/CDCS.2001.918740","url":null,"abstract":"On-demand routing protocols for mobile ad hoc networks utilize route caching in different forms in order to reduce the routing overheads as well as to improve the route discovery latency. For route caches to be effective, they need to adapt to frequent topology changes. Using an on-demand protocol called Dynamic Source Routing (DSR), we study the problem of keeping the caches up-to-date in dynamic ad hoc networks. Previous studies have shown that cache staleness in DSR can significantly degrade performance. We present and evaluate three techniques to improve cache correctness in DSR namely wider error notification, route expiry mechanism with adaptive timeout selection and the use of negative caches. Simulation results show that the combination of the proposed techniques not only result in substantial improvement of both application and cache performance but also reduce the overheads.","PeriodicalId":273489,"journal":{"name":"Proceedings 21st International Conference on Distributed Computing Systems Workshops","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123928703","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 : 2001-04-01DOI: 10.1109/CDCS.2001.918705
Lalana Kagal, Vlad Korolev, Harry Chen, A. Joshi, Timothy W. Finin
In an age where wirelessly networked appliances and devices are becoming commonplace, there is a necessity for connecting them to work together for a mobile user. The design outlined in the paper provides an infrastructure and communication protocol for providing 'smart' services to these mobile devices. This flexible framework allows any medium to be used for communication between the system and the portable device, including infra-red, and BlueTooth. Using Extensible Markup Language (XML) for information passing, gives the system a uniform and easily adaptable interface. We explain our trade-offs in implementation and through experiments we show that the design is feasible and that it indeed provides a flexible structure for providing services. Centaurus provides a uniform infrastructure for heterogeneous services, both hardware and software services, to be made available to the users everywhere where they are needed.
{"title":"Centaurus: a framework for intelligent services in a mobile environment","authors":"Lalana Kagal, Vlad Korolev, Harry Chen, A. Joshi, Timothy W. Finin","doi":"10.1109/CDCS.2001.918705","DOIUrl":"https://doi.org/10.1109/CDCS.2001.918705","url":null,"abstract":"In an age where wirelessly networked appliances and devices are becoming commonplace, there is a necessity for connecting them to work together for a mobile user. The design outlined in the paper provides an infrastructure and communication protocol for providing 'smart' services to these mobile devices. This flexible framework allows any medium to be used for communication between the system and the portable device, including infra-red, and BlueTooth. Using Extensible Markup Language (XML) for information passing, gives the system a uniform and easily adaptable interface. We explain our trade-offs in implementation and through experiments we show that the design is feasible and that it indeed provides a flexible structure for providing services. Centaurus provides a uniform infrastructure for heterogeneous services, both hardware and software services, to be made available to the users everywhere where they are needed.","PeriodicalId":273489,"journal":{"name":"Proceedings 21st International Conference on Distributed Computing Systems Workshops","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130347377","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 : 1900-01-01DOI: 10.1109/CDCS.2001.918720
Lain-Chyr Hwang, S. J. Hsu, C. Ku, Hsin-Tzung Wu
A new technique for congestion control, named ping-pong flow control (PPFC), for ATM available bit-rate (ABR) traffic is presented. It is a rate-based flow control scheme. PPFC uses a hybrid feedback strategy called "bipolar feedback". We also introduce a technique called "state early detection" that enables PPFC to control traffic flows more accurately at critical moments. In practicality, we offer an implementation of PPFC on both ATM switches and end-stations. Simulation results show that the proposed algorithm has higher throughput and a lower cell loss ratio when compared to the well-known BECN (backward explicit congestion notification) algorithm. These results also prove that our algorithm has excellent defense against feedback losses.
{"title":"An implementation of ping-pong flow control in ATM","authors":"Lain-Chyr Hwang, S. J. Hsu, C. Ku, Hsin-Tzung Wu","doi":"10.1109/CDCS.2001.918720","DOIUrl":"https://doi.org/10.1109/CDCS.2001.918720","url":null,"abstract":"A new technique for congestion control, named ping-pong flow control (PPFC), for ATM available bit-rate (ABR) traffic is presented. It is a rate-based flow control scheme. PPFC uses a hybrid feedback strategy called \"bipolar feedback\". We also introduce a technique called \"state early detection\" that enables PPFC to control traffic flows more accurately at critical moments. In practicality, we offer an implementation of PPFC on both ATM switches and end-stations. Simulation results show that the proposed algorithm has higher throughput and a lower cell loss ratio when compared to the well-known BECN (backward explicit congestion notification) algorithm. These results also prove that our algorithm has excellent defense against feedback losses.","PeriodicalId":273489,"journal":{"name":"Proceedings 21st International Conference on Distributed Computing Systems Workshops","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117247580","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 : 1900-01-01DOI: 10.1109/CDCS.2001.918690
Karsten A. Schulz, M. Orlowska
In a world of electronic interconnectivity, concepts for process automation within an organisation need to be extended to support co-operation with customers and partners across organisational boundaries. Current workflow standards provide only limited support to enable this interconnectivity. We propose a model for tiering business processes into the private business processes of organisations and those shared business processes that interconnect them. Private business processes can expose interaction points, and shared processes can link to these points so that an overall business process may span two or more organisations. The interaction points can selectively expose information about the processes and process tasks of an organisation. This paper also shows how these ideas can be supported by a coordinating architecture and describes a prototype that implements the key ideas. The proposed architecture that supports inter-organisational business processes was initially validated in the Vega final demonstration that brought together six different companies in a virtual enterprise. The implementation built upon OMG's Workflow Management Facility Specification concept for inter-workflow management interfaces, incorporated existing workflow management systems, including SAP R/3, and also non-process-oriented systems. Available services were selected at run time according to their capabilities and their availability. Experience from the demonstration with all the involved components showed a dynamic linkage between existing business processes and reliable communication between the business partners.
{"title":"Architectural issues for cross-organisational B2B interactions","authors":"Karsten A. Schulz, M. Orlowska","doi":"10.1109/CDCS.2001.918690","DOIUrl":"https://doi.org/10.1109/CDCS.2001.918690","url":null,"abstract":"In a world of electronic interconnectivity, concepts for process automation within an organisation need to be extended to support co-operation with customers and partners across organisational boundaries. Current workflow standards provide only limited support to enable this interconnectivity. We propose a model for tiering business processes into the private business processes of organisations and those shared business processes that interconnect them. Private business processes can expose interaction points, and shared processes can link to these points so that an overall business process may span two or more organisations. The interaction points can selectively expose information about the processes and process tasks of an organisation. This paper also shows how these ideas can be supported by a coordinating architecture and describes a prototype that implements the key ideas. The proposed architecture that supports inter-organisational business processes was initially validated in the Vega final demonstration that brought together six different companies in a virtual enterprise. The implementation built upon OMG's Workflow Management Facility Specification concept for inter-workflow management interfaces, incorporated existing workflow management systems, including SAP R/3, and also non-process-oriented systems. Available services were selected at run time according to their capabilities and their availability. Experience from the demonstration with all the involved components showed a dynamic linkage between existing business processes and reliable communication between the business partners.","PeriodicalId":273489,"journal":{"name":"Proceedings 21st International Conference on Distributed Computing Systems Workshops","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125367876","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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