Pub Date : 2006-11-01DOI: 10.1109/COLCOM.2006.361837
Felix Hupfeld, M. Gordon
Optimistic replication allows mobile workspaces to remain accessible during interrupted network access, but require consecutive handling of any conflicts. When conflict handling requires manual intervention by the user, the system must not require that conflicts are resolved immediatley after their detection. We present a log-based algorithm for reconciling changes to replicated data that supports deferred manual conflict resolution, while sharing the favorable scalability properties of log-based approaches of small storage and communication overhead. Simulation results validate our design and show that it compares favorably in the relevant metrics with version vector-based designs.
{"title":"Using distributed consistent branching for efficient reconciliation of mobile workspaces","authors":"Felix Hupfeld, M. Gordon","doi":"10.1109/COLCOM.2006.361837","DOIUrl":"https://doi.org/10.1109/COLCOM.2006.361837","url":null,"abstract":"Optimistic replication allows mobile workspaces to remain accessible during interrupted network access, but require consecutive handling of any conflicts. When conflict handling requires manual intervention by the user, the system must not require that conflicts are resolved immediatley after their detection. We present a log-based algorithm for reconciling changes to replicated data that supports deferred manual conflict resolution, while sharing the favorable scalability properties of log-based approaches of small storage and communication overhead. Simulation results validate our design and show that it compares favorably in the relevant metrics with version vector-based designs.","PeriodicalId":315775,"journal":{"name":"2006 International Conference on Collaborative Computing: Networking, Applications and Worksharing","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122560966","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 : 2006-11-01DOI: 10.1109/COLCOM.2006.361874
P. Knezevic, A. Wombacher, T. Risse
An essential issue in peer-to-peer data management is to keep data highly available all the time. A common idea is to replicate data hoping that at least one replica is available when needed. However, due to churns, the number of created replicas could be not sufficient for guaranteeing the intended data availability. If the number of replicas is computed according to the lowest expected peer availability (a classical case), but the expectation were too high, then the peer availability after a churn could be too low, and the system could not be able to recover the requested data availability. The paper is a continuation of previous work (Knezevic et al., 2006) and presents a replication protocol that delivers a configured data availability guarantee, and is resistant to, or recovers fast from churns. The protocol is based on a distributed hash table (DHT), measurement of peer online probability in the system, and adjustment of the number of replicas accordingly. The evaluation shows that we are able to maintain or recover the requested data availability during or shortly after stronger or weaker churns, and at the same time the storage overhead is close to the theoretical minimum
点对点数据管理的一个基本问题是始终保持数据的高可用性。一个常见的想法是复制数据，希望在需要时至少有一个副本可用。但是，由于频繁切换，创建的副本数量可能不足以保证预期的数据可用性。如果副本的数量是根据最低期望的对等可用性计算的(典型情况)，但是期望过高，那么在中断后对等可用性可能过低，系统无法恢复所请求的数据可用性。这篇论文是之前工作(Knezevic et al.， 2006)的延续，并提出了一种复制协议，该协议提供了配置的数据可用性保证，并且可以抵抗或从中断中快速恢复。该协议基于分布式哈希表(DHT)，测量系统中对等在线的概率，并相应地调整副本的数量。评估表明，我们能够在较强或较弱的震荡期间或之后不久维护或恢复所请求的数据可用性，同时存储开销接近理论最小值
{"title":"Managing and Recovering High Data Availability in a DHT under Churn","authors":"P. Knezevic, A. Wombacher, T. Risse","doi":"10.1109/COLCOM.2006.361874","DOIUrl":"https://doi.org/10.1109/COLCOM.2006.361874","url":null,"abstract":"An essential issue in peer-to-peer data management is to keep data highly available all the time. A common idea is to replicate data hoping that at least one replica is available when needed. However, due to churns, the number of created replicas could be not sufficient for guaranteeing the intended data availability. If the number of replicas is computed according to the lowest expected peer availability (a classical case), but the expectation were too high, then the peer availability after a churn could be too low, and the system could not be able to recover the requested data availability. The paper is a continuation of previous work (Knezevic et al., 2006) and presents a replication protocol that delivers a configured data availability guarantee, and is resistant to, or recovers fast from churns. The protocol is based on a distributed hash table (DHT), measurement of peer online probability in the system, and adjustment of the number of replicas accordingly. The evaluation shows that we are able to maintain or recover the requested data availability during or shortly after stronger or weaker churns, and at the same time the storage overhead is close to the theoretical minimum","PeriodicalId":315775,"journal":{"name":"2006 International Conference on Collaborative Computing: Networking, Applications and Worksharing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129592465","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 : 2006-11-01DOI: 10.1109/COLCOM.2006.361865
W. Appelt, Sanjin Pajo, W. Prinz
In this paper, we discuss security issues of Web based CSCW systems and describe a conceptual model as well a recent extension to the BSCW Shared Workspace System (Appelt, 1999) that satisfies high security requirements for communication and cooperation in an inter-organizational setting by using encryption technology
{"title":"Secure Communication and Cooperation via Shared Workspaces","authors":"W. Appelt, Sanjin Pajo, W. Prinz","doi":"10.1109/COLCOM.2006.361865","DOIUrl":"https://doi.org/10.1109/COLCOM.2006.361865","url":null,"abstract":"In this paper, we discuss security issues of Web based CSCW systems and describe a conceptual model as well a recent extension to the BSCW Shared Workspace System (Appelt, 1999) that satisfies high security requirements for communication and cooperation in an inter-organizational setting by using encryption technology","PeriodicalId":315775,"journal":{"name":"2006 International Conference on Collaborative Computing: Networking, Applications and Worksharing","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129683220","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 : 2006-11-01DOI: 10.1109/COLCOM.2006.361892
Jing Jin, Gail-Joon Ahn
The introduction of service-oriented paradigm in grid and corresponding Web services standards has recently demanded the evolution of access control solutions to support finegrained authorization requirements and dynamic natures derived from grid environments. In this paper, we present a role-based authorization infrastructure for data sharing and management services in grid. Our infrastructure advocates a dynamic and flexible resource-centric authorization approach with features of distributed role-based access control and systematic delegation of administrative authority. The infrastructure seamlessly integrates the existing XACML-based policy framework and authorization services in the RAMARS framework. We discuss our proof-of-concept prototype system that supports Web services and SAML based authorization assertions. We also describe how the framework can be deployed in being compatible with an open grid service architecture
{"title":"Towards Secure Information Sharing and Management in Grid Environments","authors":"Jing Jin, Gail-Joon Ahn","doi":"10.1109/COLCOM.2006.361892","DOIUrl":"https://doi.org/10.1109/COLCOM.2006.361892","url":null,"abstract":"The introduction of service-oriented paradigm in grid and corresponding Web services standards has recently demanded the evolution of access control solutions to support finegrained authorization requirements and dynamic natures derived from grid environments. In this paper, we present a role-based authorization infrastructure for data sharing and management services in grid. Our infrastructure advocates a dynamic and flexible resource-centric authorization approach with features of distributed role-based access control and systematic delegation of administrative authority. The infrastructure seamlessly integrates the existing XACML-based policy framework and authorization services in the RAMARS framework. We discuss our proof-of-concept prototype system that supports Web services and SAML based authorization assertions. We also describe how the framework can be deployed in being compatible with an open grid service architecture","PeriodicalId":315775,"journal":{"name":"2006 International Conference on Collaborative Computing: Networking, Applications and Worksharing","volume":"120 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132480594","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 : 2006-11-01DOI: 10.1109/COLCOM.2006.361879
Zhixiong Zhang, Xinwen Zhang, R. Sandhu
In RBAC, roles are typically created based on job functions inside an organization. Traditional RBAC does not scale up well for modeling security policies spanning multiple organizations. To solve this problem, a family of extended RBAC models called role and organization based access control (ROBAC) models is proposed and formalized in this paper. Two examples are used to motivate and demonstrate the usefulness of ROBAC. Comparison between ROBAC and other related RBAC models is given. We show that ROBAC can significantly reduce administration complexity for Web and Internet-based applications involving a large number of organizations. Some administrative issues for ROBAC are identified and discussed. Although the theoretical-expressive power of ROBAC is the same as that of RBAC, it is more succinct and intuitive to use ROBAC than to use RBAC when applications involve many organizations
{"title":"ROBAC: Scalable Role and Organization Based Access Control Models","authors":"Zhixiong Zhang, Xinwen Zhang, R. Sandhu","doi":"10.1109/COLCOM.2006.361879","DOIUrl":"https://doi.org/10.1109/COLCOM.2006.361879","url":null,"abstract":"In RBAC, roles are typically created based on job functions inside an organization. Traditional RBAC does not scale up well for modeling security policies spanning multiple organizations. To solve this problem, a family of extended RBAC models called role and organization based access control (ROBAC) models is proposed and formalized in this paper. Two examples are used to motivate and demonstrate the usefulness of ROBAC. Comparison between ROBAC and other related RBAC models is given. We show that ROBAC can significantly reduce administration complexity for Web and Internet-based applications involving a large number of organizations. Some administrative issues for ROBAC are identified and discussed. Although the theoretical-expressive power of ROBAC is the same as that of RBAC, it is more succinct and intuitive to use ROBAC than to use RBAC when applications involve many organizations","PeriodicalId":315775,"journal":{"name":"2006 International Conference on Collaborative Computing: Networking, Applications and Worksharing","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116205467","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 : 2006-11-01DOI: 10.1109/COLCOM.2006.361884
H. Khurana, J. Basney, Von Welch, R. Campbell
Large collaborative infrastructures that span multiple organizations such as those that enable grid computing and scientific experimentation are being deployed and used today. In order to secure these infrastructures a comprehensive requirements study is needed that takes into account the novel risks, threats, and operational issues brought on by the large-scale, distributed nature of these systems. In this paper we argue that gaps in security policies and procedures combined with organizational autonomy are the primary drivers motivating a set of requirements that go beyond those observed today. With three example infrastructures in mind, namely, Teragrid, LHC Grid, and GEM, we explore the novel risks, threats, and operational issues to compose a set of operational security requirements; the satisfaction of which are essential for securing such large collaborative infrastructures
{"title":"Operational Security Requirements for Large Collaborative Compute Infrastructures","authors":"H. Khurana, J. Basney, Von Welch, R. Campbell","doi":"10.1109/COLCOM.2006.361884","DOIUrl":"https://doi.org/10.1109/COLCOM.2006.361884","url":null,"abstract":"Large collaborative infrastructures that span multiple organizations such as those that enable grid computing and scientific experimentation are being deployed and used today. In order to secure these infrastructures a comprehensive requirements study is needed that takes into account the novel risks, threats, and operational issues brought on by the large-scale, distributed nature of these systems. In this paper we argue that gaps in security policies and procedures combined with organizational autonomy are the primary drivers motivating a set of requirements that go beyond those observed today. With three example infrastructures in mind, namely, Teragrid, LHC Grid, and GEM, we explore the novel risks, threats, and operational issues to compose a set of operational security requirements; the satisfaction of which are essential for securing such large collaborative infrastructures","PeriodicalId":315775,"journal":{"name":"2006 International Conference on Collaborative Computing: Networking, Applications and Worksharing","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116771925","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 : 2006-11-01DOI: 10.1109/COLCOM.2006.361853
V. Gruhn, André Köhler
This paper introduces a graphical modeling notation based on coloured Petri nets for the performance and cost evaluation of mobile applications. When developing such an application some restrictions due to the low bandwidth of mobile networks need to be considered. The notation can be used to model the workflow of a mobile application with just a small effort. The resulting model can be (automatically) transformed into a coloured Petri net for simulating the communication behaviour depending on typical user interactions. The simulation results are an important basis for improving the applications performance and the occurring costs for using mobile networks
{"title":"A Modeling and Analysis Approach for Mobile Information Systems","authors":"V. Gruhn, André Köhler","doi":"10.1109/COLCOM.2006.361853","DOIUrl":"https://doi.org/10.1109/COLCOM.2006.361853","url":null,"abstract":"This paper introduces a graphical modeling notation based on coloured Petri nets for the performance and cost evaluation of mobile applications. When developing such an application some restrictions due to the low bandwidth of mobile networks need to be considered. The notation can be used to model the workflow of a mobile application with just a small effort. The resulting model can be (automatically) transformed into a coloured Petri net for simulating the communication behaviour depending on typical user interactions. The simulation results are an important basis for improving the applications performance and the occurring costs for using mobile networks","PeriodicalId":315775,"journal":{"name":"2006 International Conference on Collaborative Computing: Networking, Applications and Worksharing","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122034378","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 : 2006-11-01DOI: 10.1109/COLCOM.2006.361866
Carla Valle, W. Prinz, M. Jarke
This paper describes the design and implementation of a coordination mechanism to support follow up of decisions made in meetings, using task management and semi-structured messages in an integrated way. Two questions lead our research: i) can a set of group support mechanisms, enabling the link between pre-meeting, meeting and post-meeting activities, allow for better coordination of decisions being implemented?; ii) can electronic elements, which belong to daily project scenarios, provide awareness of decision implementation's problems? Our evaluations and conclusions indicate that such elements (ie. tasks and emails) provide means for coordination of decision follow up
{"title":"Using Tasks and Semi-structured Messages to Support Decision Follow Up","authors":"Carla Valle, W. Prinz, M. Jarke","doi":"10.1109/COLCOM.2006.361866","DOIUrl":"https://doi.org/10.1109/COLCOM.2006.361866","url":null,"abstract":"This paper describes the design and implementation of a coordination mechanism to support follow up of decisions made in meetings, using task management and semi-structured messages in an integrated way. Two questions lead our research: i) can a set of group support mechanisms, enabling the link between pre-meeting, meeting and post-meeting activities, allow for better coordination of decisions being implemented?; ii) can electronic elements, which belong to daily project scenarios, provide awareness of decision implementation's problems? Our evaluations and conclusions indicate that such elements (ie. tasks and emails) provide means for coordination of decision follow up","PeriodicalId":315775,"journal":{"name":"2006 International Conference on Collaborative Computing: Networking, Applications and Worksharing","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129013361","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 : 2006-11-01DOI: 10.1109/COLCOM.2006.361869
C. Ignat, M. Norrie
Version control systems are widely used to support a group of people working together on a set of documents over a network by merging their changes into the same source repository. The existing versioning systems offer limited support concerning conflict resolution and tracking of user activity. In this paper we propose a multi-level editing approach that keeps the editing operations that refer to an element of a hierarchical document associated with that element. In this way, customisable merging is achieved, where the conflicts can be specified and resolved at different granularity levels
{"title":"Flexible Definition and Resolution of Conflicts through Multi-level Editing","authors":"C. Ignat, M. Norrie","doi":"10.1109/COLCOM.2006.361869","DOIUrl":"https://doi.org/10.1109/COLCOM.2006.361869","url":null,"abstract":"Version control systems are widely used to support a group of people working together on a set of documents over a network by merging their changes into the same source repository. The existing versioning systems offer limited support concerning conflict resolution and tracking of user activity. In this paper we propose a multi-level editing approach that keeps the editing operations that refer to an element of a hierarchical document associated with that element. In this way, customisable merging is achieved, where the conflicts can be specified and resolved at different granularity levels","PeriodicalId":315775,"journal":{"name":"2006 International Conference on Collaborative Computing: Networking, Applications and Worksharing","volume":"274 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115972492","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 : 2006-11-01DOI: 10.1109/COLCOM.2006.361858
J. Preston, S. Prasad
The primary goals in a synchronous collaborative editing system (CES) involve ensuring a high level of concurrent access while maintaining the properties of the CCI model. We revisit the idea of applying lock-based concurrency control algorithms to manage access to a shared document; this research overcomes the traditional problem of reduced concurrent access inherent in pessimistic concurrency control by dynamically managing the size of the portion of document locked based upon user demand, scaling up and down the lock granularity to accommodate user write requests. We present algorithms to efficiently maximize concurrent access while utilizing caching techniques to reduce communication costs. We also discuss how OT and other optimistic concurrency control techniques may be incorporated within our approach - leveraging best practices of both techniques. We conclude with an analysis of the communication and computational costs of our approach and compare these costs to costs incurred using OT-based concurrency control
{"title":"An Efficient Synchronous Collaborative Editing System Employing Dynamic Locking of Varying Granularity in Generalized Document Trees","authors":"J. Preston, S. Prasad","doi":"10.1109/COLCOM.2006.361858","DOIUrl":"https://doi.org/10.1109/COLCOM.2006.361858","url":null,"abstract":"The primary goals in a synchronous collaborative editing system (CES) involve ensuring a high level of concurrent access while maintaining the properties of the CCI model. We revisit the idea of applying lock-based concurrency control algorithms to manage access to a shared document; this research overcomes the traditional problem of reduced concurrent access inherent in pessimistic concurrency control by dynamically managing the size of the portion of document locked based upon user demand, scaling up and down the lock granularity to accommodate user write requests. We present algorithms to efficiently maximize concurrent access while utilizing caching techniques to reduce communication costs. We also discuss how OT and other optimistic concurrency control techniques may be incorporated within our approach - leveraging best practices of both techniques. We conclude with an analysis of the communication and computational costs of our approach and compare these costs to costs incurred using OT-based concurrency control","PeriodicalId":315775,"journal":{"name":"2006 International Conference on Collaborative Computing: Networking, Applications and Worksharing","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2006-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127532624","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：