Pub Date : 1996-06-03DOI: 10.1109/SDNE.1996.502446
U. Leonhardt, Jeff Magee
With the advent of mobile computing devices and cheap location sensing systems, location information has become an important resource both for mobile and 'desktop' users. We describe some key concepts a scalable ubiquitous location service should be based on. Firstly, we discuss the general problem of client-server computing in mobile environments. Secondly, we describe the theoretical and design framework for a general location service. We address the use of multiple sources of location information. Further, we describe location domains as a powerful framework for presenting and protecting location information.
{"title":"Towards a general location service for mobile environments","authors":"U. Leonhardt, Jeff Magee","doi":"10.1109/SDNE.1996.502446","DOIUrl":"https://doi.org/10.1109/SDNE.1996.502446","url":null,"abstract":"With the advent of mobile computing devices and cheap location sensing systems, location information has become an important resource both for mobile and 'desktop' users. We describe some key concepts a scalable ubiquitous location service should be based on. Firstly, we discuss the general problem of client-server computing in mobile environments. Secondly, we describe the theoretical and design framework for a general location service. We address the use of multiple sources of location information. Further, we describe location domains as a powerful framework for presenting and protecting location information.","PeriodicalId":112195,"journal":{"name":"Proceedings of Third International Workshop on Services in Distributed and Networked Environments","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127514924","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 : 1996-06-03DOI: 10.1109/SDNE.1996.502444
K. Cheverst, N. Davies, A. Friday, G. Blair
This paper describes the design of services to support consistency in collaborative mobile applications. The requirements for application level consistency in groupware applications are discussed and it is argued that existing consistency services for mobile environments fail to address these requirements because they assume infrequent (write) sharing of information. We present the design of a group execution service called G-QEX which is designed to support consistency in mobile applications and includes features necessary to cope with the fluctuations in QoS which characterise mobile environments.
{"title":"Services to support consistency in mobile collaborative applications","authors":"K. Cheverst, N. Davies, A. Friday, G. Blair","doi":"10.1109/SDNE.1996.502444","DOIUrl":"https://doi.org/10.1109/SDNE.1996.502444","url":null,"abstract":"This paper describes the design of services to support consistency in collaborative mobile applications. The requirements for application level consistency in groupware applications are discussed and it is argued that existing consistency services for mobile environments fail to address these requirements because they assume infrequent (write) sharing of information. We present the design of a group execution service called G-QEX which is designed to support consistency in mobile applications and includes features necessary to cope with the fluctuations in QoS which characterise mobile environments.","PeriodicalId":112195,"journal":{"name":"Proceedings of Third International Workshop on Services in Distributed and Networked Environments","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125024227","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 : 1996-06-03DOI: 10.1109/SDNE.1996.502443
S. Pope
Mobile computers, termed Walkstations are expected to be used under massively changing conditions. In order to operate effectively they must adapt their behaviour as conditions change. This paper presents a low latency, heterogeneous application migration service, built from a distributed programming environment, which enables applications to adapt from a rich, office based computing environment to one which is more self-reliant.
{"title":"Application migration for mobile computers","authors":"S. Pope","doi":"10.1109/SDNE.1996.502443","DOIUrl":"https://doi.org/10.1109/SDNE.1996.502443","url":null,"abstract":"Mobile computers, termed Walkstations are expected to be used under massively changing conditions. In order to operate effectively they must adapt their behaviour as conditions change. This paper presents a low latency, heterogeneous application migration service, built from a distributed programming environment, which enables applications to adapt from a rich, office based computing environment to one which is more self-reliant.","PeriodicalId":112195,"journal":{"name":"Proceedings of Third International Workshop on Services in Distributed and Networked Environments","volume":"145 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126640897","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 : 1996-06-03DOI: 10.1109/SDNE.1996.502453
E. Grasso
Concurrency is a paramount concern in a real-time system, where a trade-off exists between high availability on the one hand and application consistency on the other. We argue that a traditional concurrency control service (CCS) based on a predefined set of lock modes may be too confining as it does not allow the programmer to set their own concurrency level tailored to application semantics. We propose a programmable concurrency control service (PCCS) that addresses precisely the problem mentioned above. The PCCS is defined as a CORBA Object Service and is a smooth extension of the standard OMG concurrency control service. Compared with OMG CCS, the PCCS better responds to real-time demands by allowing the specification of the number and conflict-level of lock modes.
{"title":"A programmable concurrency control service for CORBA","authors":"E. Grasso","doi":"10.1109/SDNE.1996.502453","DOIUrl":"https://doi.org/10.1109/SDNE.1996.502453","url":null,"abstract":"Concurrency is a paramount concern in a real-time system, where a trade-off exists between high availability on the one hand and application consistency on the other. We argue that a traditional concurrency control service (CCS) based on a predefined set of lock modes may be too confining as it does not allow the programmer to set their own concurrency level tailored to application semantics. We propose a programmable concurrency control service (PCCS) that addresses precisely the problem mentioned above. The PCCS is defined as a CORBA Object Service and is a smooth extension of the standard OMG concurrency control service. Compared with OMG CCS, the PCCS better responds to real-time demands by allowing the specification of the number and conflict-level of lock modes.","PeriodicalId":112195,"journal":{"name":"Proceedings of Third International Workshop on Services in Distributed and Networked Environments","volume":"255 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114362140","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 : 1996-06-03DOI: 10.1109/SDNE.1996.502456
N. Baukari, A. Aljane
This paper describes an implementation architecture of an auditing system applied to a simulated virtual private network service. It analyses the VPN security and audit requirements and illustrates the auditing system components: the audit manager, the audit and the virtual private network service managed objects.
{"title":"Security and auditing of VPN","authors":"N. Baukari, A. Aljane","doi":"10.1109/SDNE.1996.502456","DOIUrl":"https://doi.org/10.1109/SDNE.1996.502456","url":null,"abstract":"This paper describes an implementation architecture of an auditing system applied to a simulated virtual private network service. It analyses the VPN security and audit requirements and illustrates the auditing system components: the audit manager, the audit and the virtual private network service managed objects.","PeriodicalId":112195,"journal":{"name":"Proceedings of Third International Workshop on Services in Distributed and Networked Environments","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122124070","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 : 1996-06-03DOI: 10.1109/SDNE.1996.502454
A. Vogel, B. Gray, K. Duddy
The co-existence of middleware platforms, eg. DCE and CORBA, creates a new problem of heterogeneity-the heterogeneity of middleware platforms. In this paper a partial approach to overcoming this heterogeneity is presented-the translation between different interface definition languages (IDL) and the comparison of interface specifications in different IDLs. In particular, a mapping between DCE IDL and OMG IDL and the corresponding translation tools are presented. Furthermore, various definitions of sub-typing of interface specifications are investigated for their suitability in comparing specifications in different IDLs.
{"title":"Understanding any IDL lesson one: DCE and CORBA","authors":"A. Vogel, B. Gray, K. Duddy","doi":"10.1109/SDNE.1996.502454","DOIUrl":"https://doi.org/10.1109/SDNE.1996.502454","url":null,"abstract":"The co-existence of middleware platforms, eg. DCE and CORBA, creates a new problem of heterogeneity-the heterogeneity of middleware platforms. In this paper a partial approach to overcoming this heterogeneity is presented-the translation between different interface definition languages (IDL) and the comparison of interface specifications in different IDLs. In particular, a mapping between DCE IDL and OMG IDL and the corresponding translation tools are presented. Furthermore, various definitions of sub-typing of interface specifications are investigated for their suitability in comparing specifications in different IDLs.","PeriodicalId":112195,"journal":{"name":"Proceedings of Third International Workshop on Services in Distributed and Networked Environments","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130820367","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 : 1996-06-03DOI: 10.1109/SDNE.1996.502458
K. Maly, A. Gupta, B. Kvande, I. Levinstein, R. Mukkamala, M. Olson, R. Whitney, R. Chambers
Modern research projects may involve dozens of geographically distributed collaborators who access distributed information, applications workstations and devices. We are developing an architecture and methods for distributed, decentralized privilege management and enforcement with regard to access to distributed mass storage data and information via the Internet. Our approach does not require modification of the supporting operating system yet provides a more flexible and finer grained privilege system. We use X-windows and World Wide Web based interfaces in secure environments which support authentication and authorization. Toward this end, we have established secure distributed computing environment (DCE) networks at two sites and implemented selected features of the system. In this paper we report the design and implementation details of the project and summarize the issues that need to be resolved in future. The initial work is part of a larger Distributed Informatics Computing and Collaborative Environments (DICCE) project associated with the US Department of Energy's Energy Science Network (ESnet). The particular project is a joint effort between the Continuous Electron Beam Accelerator Facility (CEBAF), the Chinese Institute of High Energy Physics, and Old Dominion University.
{"title":"A privilege management system for a secure network","authors":"K. Maly, A. Gupta, B. Kvande, I. Levinstein, R. Mukkamala, M. Olson, R. Whitney, R. Chambers","doi":"10.1109/SDNE.1996.502458","DOIUrl":"https://doi.org/10.1109/SDNE.1996.502458","url":null,"abstract":"Modern research projects may involve dozens of geographically distributed collaborators who access distributed information, applications workstations and devices. We are developing an architecture and methods for distributed, decentralized privilege management and enforcement with regard to access to distributed mass storage data and information via the Internet. Our approach does not require modification of the supporting operating system yet provides a more flexible and finer grained privilege system. We use X-windows and World Wide Web based interfaces in secure environments which support authentication and authorization. Toward this end, we have established secure distributed computing environment (DCE) networks at two sites and implemented selected features of the system. In this paper we report the design and implementation details of the project and summarize the issues that need to be resolved in future. The initial work is part of a larger Distributed Informatics Computing and Collaborative Environments (DICCE) project associated with the US Department of Energy's Energy Science Network (ESnet). The particular project is a joint effort between the Continuous Electron Beam Accelerator Facility (CEBAF), the Chinese Institute of High Energy Physics, and Old Dominion University.","PeriodicalId":112195,"journal":{"name":"Proceedings of Third International Workshop on Services in Distributed and Networked Environments","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127239062","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 : 1996-06-03DOI: 10.1109/SDNE.1996.502447
E. Monteiro, G. Quadros, F. Boavida
The characterization of congestion in communication systems is a pre-requisite for the definition of mechanisms that can be used in congestion control with the goal to minimize its effects on the performance of distributed applications. In order for those mechanisms to work properly, there is the need to quantify congestion of services and systems. This paper proposes a scheme that enables the quantification of the congestion of a particular communication service, the comparison of the congestion degree of two more services, and the quantification of the global system congestion, based on the definition of a set of system QoS parameters, of the their normal variation limits and of their degradation thresholds. The paper begins with the characterization of the congestion problem. Following, a congestion definition is presented and a congestion metric is proposed. The paper ends with an analysis of the quantification of congestion in communication systems when looked at as a set of several consecutive modules.
{"title":"A scheme for the quantification of congestion in communication services and systems","authors":"E. Monteiro, G. Quadros, F. Boavida","doi":"10.1109/SDNE.1996.502447","DOIUrl":"https://doi.org/10.1109/SDNE.1996.502447","url":null,"abstract":"The characterization of congestion in communication systems is a pre-requisite for the definition of mechanisms that can be used in congestion control with the goal to minimize its effects on the performance of distributed applications. In order for those mechanisms to work properly, there is the need to quantify congestion of services and systems. This paper proposes a scheme that enables the quantification of the congestion of a particular communication service, the comparison of the congestion degree of two more services, and the quantification of the global system congestion, based on the definition of a set of system QoS parameters, of the their normal variation limits and of their degradation thresholds. The paper begins with the characterization of the congestion problem. Following, a congestion definition is presented and a congestion metric is proposed. The paper ends with an analysis of the quantification of congestion in communication systems when looked at as a set of several consecutive modules.","PeriodicalId":112195,"journal":{"name":"Proceedings of Third International Workshop on Services in Distributed and Networked Environments","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124375383","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 : 1996-06-03DOI: 10.1109/SDNE.1996.502449
S. Kummel, A. Schill, G. Volkmann
This paper describes measurements and experiences with remote procedure call (RPC) over different network technologies, and with different levels of functionality. The major basis is the RPC of the OSF Distributed Computing Environment. We first discuss performance based on local area networks; also including secure RPC features. We then present performance results over WAN connections via the Internet and compare them with our findings in LAN settings. Another major focus area is the investigation of the RPC behavior using an ATM network as a basis for transmission. Major limitations and further requirements of client/server interactions in high performance networks are illustrated. The RPC is also evaluated in mobile environments using a cellular, GSM-based WAN. In this domain, various additional requirements have to be considered as discussed in the paper. Finally, steps towards a new integrated and enhanced request-response protocol are pointed out as a conclusion.
{"title":"RPC over advanced network technologies: evaluation and experiences","authors":"S. Kummel, A. Schill, G. Volkmann","doi":"10.1109/SDNE.1996.502449","DOIUrl":"https://doi.org/10.1109/SDNE.1996.502449","url":null,"abstract":"This paper describes measurements and experiences with remote procedure call (RPC) over different network technologies, and with different levels of functionality. The major basis is the RPC of the OSF Distributed Computing Environment. We first discuss performance based on local area networks; also including secure RPC features. We then present performance results over WAN connections via the Internet and compare them with our findings in LAN settings. Another major focus area is the investigation of the RPC behavior using an ATM network as a basis for transmission. Major limitations and further requirements of client/server interactions in high performance networks are illustrated. The RPC is also evaluated in mobile environments using a cellular, GSM-based WAN. In this domain, various additional requirements have to be considered as discussed in the paper. Finally, steps towards a new integrated and enhanced request-response protocol are pointed out as a conclusion.","PeriodicalId":112195,"journal":{"name":"Proceedings of Third International Workshop on Services in Distributed and Networked Environments","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128136601","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 : 1996-06-03DOI: 10.1109/SDNE.1996.502460
Kwang-Soo Kim
This paper deals with the service aspect of X.500 directory services to provide a user-configurable, easy-to-use, and platform-independent directory user interface. To deploy the X.500 white pages service widely, for instance, such an integrated user interface is essential. The availability of powerful World-Wide Web (WWW) clients is already providing this means if they have proper links with the X.500 directory. In this paper, the functionality has been fulfilled by implementing a customizable WWW-X.500 gateway, called Cweb500. It investigates some paramount advantages that the gateway may bring. In our X.500 pilot, the gateway has been utilized satisfactorily with many user-friendly functions, and as an integrated means that combines WWW and X.500 directory services.
{"title":"Enabling customizable World-Wide Web access to X.500 directory","authors":"Kwang-Soo Kim","doi":"10.1109/SDNE.1996.502460","DOIUrl":"https://doi.org/10.1109/SDNE.1996.502460","url":null,"abstract":"This paper deals with the service aspect of X.500 directory services to provide a user-configurable, easy-to-use, and platform-independent directory user interface. To deploy the X.500 white pages service widely, for instance, such an integrated user interface is essential. The availability of powerful World-Wide Web (WWW) clients is already providing this means if they have proper links with the X.500 directory. In this paper, the functionality has been fulfilled by implementing a customizable WWW-X.500 gateway, called Cweb500. It investigates some paramount advantages that the gateway may bring. In our X.500 pilot, the gateway has been utilized satisfactorily with many user-friendly functions, and as an integrated means that combines WWW and X.500 directory services.","PeriodicalId":112195,"journal":{"name":"Proceedings of Third International Workshop on Services in Distributed and Networked Environments","volume":"286 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132062139","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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