K. Veeraraghavan, Edmund B. Nightingale, J. Flinn, Brian D. Noble
We introduce a unifying file system abstraction, called a quFile, that provides a new mechanism for implementing mobile data management policies. quFiles allow arbitrary data types to be bundled together without confusing the user. Similar to a quBit (quantum bit), the particular data displayed by a quFile is not determined until the moment it is observed. A quFile displays the appropriate data type and version depending upon an application-specific policy that can take any information into account, such as the platform, external devices, context, connectivity, or battery power. We first describe what the quFile mechanism provides to applications and mobile devices. We then discuss how quFiles can benefit mobile data management in the areas of resource management, extensibility, and data consistency and availability.
{"title":"quFiles: a unifying abstraction for mobile data management","authors":"K. Veeraraghavan, Edmund B. Nightingale, J. Flinn, Brian D. Noble","doi":"10.1145/1411759.1411777","DOIUrl":"https://doi.org/10.1145/1411759.1411777","url":null,"abstract":"We introduce a unifying file system abstraction, called a quFile, that provides a new mechanism for implementing mobile data management policies. quFiles allow arbitrary data types to be bundled together without confusing the user. Similar to a quBit (quantum bit), the particular data displayed by a quFile is not determined until the moment it is observed. A quFile displays the appropriate data type and version depending upon an application-specific policy that can take any information into account, such as the platform, external devices, context, connectivity, or battery power. We first describe what the quFile mechanism provides to applications and mobile devices. We then discuss how quFiles can benefit mobile data management in the areas of resource management, extensibility, and data consistency and availability.","PeriodicalId":88972,"journal":{"name":"Proceedings. IEEE Workshop on Mobile Computing Systems and Applications","volume":"103 1","pages":"65-68"},"PeriodicalIF":0.0,"publicationDate":"2008-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90083646","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 : 1994-12-08DOI: 10.1109/MCSA.1994.513485
A. Herzberg, H. Krawczyk, G. Tsudik
User mobility is rapidly becoming an important and popular feature in today's networks. This is especially evident in wireless/cellular environments. While useful and desirable, user mobility raises a number of important security related issues and concerns. One of them is the issue of tracking mobile user's movements and current whereabouts. Ideally, no entity other than the user himself and a responsible authority in the user's home domain should know either the real identity or the current location of the mobile user. At present, environments supporting user mobility either do not address the problem at all or base their solutions on the specific hardware capabilities of the user's personal device, e.g., a cellular telephone. The paper discusses a wide range of issues related to anonymity in mobile environments, reviews current state of the art approaches and proposes several potential solutions. Solutions vary in complexity, degree of protection and assumptions about the underlying environment.
{"title":"On travelling incognito [mobile computing]","authors":"A. Herzberg, H. Krawczyk, G. Tsudik","doi":"10.1109/MCSA.1994.513485","DOIUrl":"https://doi.org/10.1109/MCSA.1994.513485","url":null,"abstract":"User mobility is rapidly becoming an important and popular feature in today's networks. This is especially evident in wireless/cellular environments. While useful and desirable, user mobility raises a number of important security related issues and concerns. One of them is the issue of tracking mobile user's movements and current whereabouts. Ideally, no entity other than the user himself and a responsible authority in the user's home domain should know either the real identity or the current location of the mobile user. At present, environments supporting user mobility either do not address the problem at all or base their solutions on the specific hardware capabilities of the user's personal device, e.g., a cellular telephone. The paper discusses a wide range of issues related to anonymity in mobile environments, reviews current state of the art approaches and proposes several potential solutions. Solutions vary in complexity, degree of protection and assumptions about the underlying environment.","PeriodicalId":88972,"journal":{"name":"Proceedings. IEEE Workshop on Mobile Computing Systems and Applications","volume":"5 1","pages":"205-211"},"PeriodicalIF":0.0,"publicationDate":"1994-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89938651","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 : 1994-12-08DOI: 10.1109/MCSA.1994.513486
M. Satyanarayanan
{"title":"Workshop on Mobile Computing Systems and Applications December 1994","authors":"M. Satyanarayanan","doi":"10.1109/MCSA.1994.513486","DOIUrl":"https://doi.org/10.1109/MCSA.1994.513486","url":null,"abstract":"","PeriodicalId":88972,"journal":{"name":"Proceedings. IEEE Workshop on Mobile Computing Systems and Applications","volume":"126 1","pages":"212-"},"PeriodicalIF":0.0,"publicationDate":"1994-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73590348","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 : 1994-12-08DOI: 10.1109/MCSA.1994.512729
J. Saldanha, D. Cohn
Existing distributed file systems are based on either a client-server model or a peer-to-peer model. We believe that the dynamic conditions of mobile computing and new classes of devices such as PDAs will no longer permit rigid adherence to either of these models. We argue that a hybrid of the two will have to be used. We then propose a file system design based on such a model which exploits the ability of highly portable devices like PDAs to be carried by their owners at all times. We examine the relationship between mobile computing personae and file systems and show how the personae concept can be used to support the file system needs of mobile users. Finally we discuss some issues raised by the implementation we are building.
{"title":"A hybrid model for mobile file systems","authors":"J. Saldanha, D. Cohn","doi":"10.1109/MCSA.1994.512729","DOIUrl":"https://doi.org/10.1109/MCSA.1994.512729","url":null,"abstract":"Existing distributed file systems are based on either a client-server model or a peer-to-peer model. We believe that the dynamic conditions of mobile computing and new classes of devices such as PDAs will no longer permit rigid adherence to either of these models. We argue that a hybrid of the two will have to be used. We then propose a file system design based on such a model which exploits the ability of highly portable devices like PDAs to be carried by their owners at all times. We examine the relationship between mobile computing personae and file systems and show how the personae concept can be used to support the file system needs of mobile users. Finally we discuss some issues raised by the implementation we are building.","PeriodicalId":88972,"journal":{"name":"Proceedings. IEEE Workshop on Mobile Computing Systems and Applications","volume":"11 1","pages":"20-23"},"PeriodicalIF":0.0,"publicationDate":"1994-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91214314","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 : 1994-12-08DOI: 10.1109/MCSA.1994.513477
E. Pitoura, B. Bhargava
It is expected that in the near future millions of users will have access to on-line distributed databases through mobile computers. The restrictions imposed by the nature of the wireless medium and the resulting mobility of data consumers and data producers make traditional transaction models inadequate. In this paper, we investigate means for providing transaction support appropriate for mobile environments. Specifically, we define a model that ensures a weaker notion of consistency, accounts for mobility, and provides for recovery.
{"title":"Revising transaction concepts for mobile computing","authors":"E. Pitoura, B. Bhargava","doi":"10.1109/MCSA.1994.513477","DOIUrl":"https://doi.org/10.1109/MCSA.1994.513477","url":null,"abstract":"It is expected that in the near future millions of users will have access to on-line distributed databases through mobile computers. The restrictions imposed by the nature of the wireless medium and the resulting mobility of data consumers and data producers make traditional transaction models inadequate. In this paper, we investigate means for providing transaction support appropriate for mobile environments. Specifically, we define a model that ensures a weaker notion of consistency, accounts for mobility, and provides for recovery.","PeriodicalId":88972,"journal":{"name":"Proceedings. IEEE Workshop on Mobile Computing Systems and Applications","volume":"3 1","pages":"164-168"},"PeriodicalIF":0.0,"publicationDate":"1994-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75658391","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 : 1994-01-01DOI: 10.1109/MCSA.1994.513473
D. G. Messerschmidt, J. M. Reason, A. Lao
Wireless access to continuous-media services is becoming increasingly prevalent. An interactive video service is one such service, but existing compression standards are unsatisfactory for wireless packet-video services. We propose a novel strategy for video transport using a layered source coder in conjunction with a variable quality-of-service, multiple-substream abstraction for the transport. This abstraction specifically addresses the need to simultaneously obtain high spectral efficiency, good subjective quality and low perceptual delay on a wireless channel (perceptual delay is the effective end-to-end latency observed by the user). The abstraction also addresses the heterogenous transport resulting from the concatenation of a wireless access link with a broadband backbone network. We use asynchronous video reconstruction, running counter to current techniques which use strictly synchronous video processing. By doing so, we hope to achieve a perceptual delay that is much lower than the worst-case transport delay. By identifying packets to the transport with relaxed reliability and/or delay requirements, the transport can achieve high traffic capacity. Reasonable and promising simulation results are achieved, although much work remains on achieving significant video compression in this environment.
{"title":"Asynchronous video coding for wireless transport","authors":"D. G. Messerschmidt, J. M. Reason, A. Lao","doi":"10.1109/MCSA.1994.513473","DOIUrl":"https://doi.org/10.1109/MCSA.1994.513473","url":null,"abstract":"Wireless access to continuous-media services is becoming increasingly prevalent. An interactive video service is one such service, but existing compression standards are unsatisfactory for wireless packet-video services. We propose a novel strategy for video transport using a layered source coder in conjunction with a variable quality-of-service, multiple-substream abstraction for the transport. This abstraction specifically addresses the need to simultaneously obtain high spectral efficiency, good subjective quality and low perceptual delay on a wireless channel (perceptual delay is the effective end-to-end latency observed by the user). The abstraction also addresses the heterogenous transport resulting from the concatenation of a wireless access link with a broadband backbone network. We use asynchronous video reconstruction, running counter to current techniques which use strictly synchronous video processing. By doing so, we hope to achieve a perceptual delay that is much lower than the worst-case transport delay. By identifying packets to the transport with relaxed reliability and/or delay requirements, the transport can achieve high traffic capacity. Reasonable and promising simulation results are achieved, although much work remains on achieving significant video compression in this environment.","PeriodicalId":88972,"journal":{"name":"Proceedings. IEEE Workshop on Mobile Computing Systems and Applications","volume":"63 1","pages":"138-145"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73794038","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 : 1994-01-01DOI: 10.1109/MCSA.1994.512748
R. Alonso, V. Mani
The appearance on the market of pen-based computers with wireless communication capabilities has led to the ability to access geographically distributed information bases. Moreover, such computing devices require database interfaces that are easy-to-use, avoid large-scale data input via keyboard use, and are suited for smaller display screens. We establish the need for newer interfaces to deal with problems specific to mobile computing devices that use the pen as a primary input device. We describe an implementation of a pen-based graphical database interface on a pen computer (using the PenPoint operating system) with a built-in cellular phone. Using the cellular phone capability, the interface connects to remote databases and displays the schema information of the database chosen by the user. In response to gestures made by the user using the pen, the interface automatically generates queries and retrieves results. We use the 'universal relation' concept to aid in automatically generating queries based on the attributes chosen by the user. We provide a summary of the status of this interface, some implementation details and suggest some future directions.
{"title":"A pen-based database interface for mobile computers","authors":"R. Alonso, V. Mani","doi":"10.1109/MCSA.1994.512748","DOIUrl":"https://doi.org/10.1109/MCSA.1994.512748","url":null,"abstract":"The appearance on the market of pen-based computers with wireless communication capabilities has led to the ability to access geographically distributed information bases. Moreover, such computing devices require database interfaces that are easy-to-use, avoid large-scale data input via keyboard use, and are suited for smaller display screens. We establish the need for newer interfaces to deal with problems specific to mobile computing devices that use the pen as a primary input device. We describe an implementation of a pen-based graphical database interface on a pen computer (using the PenPoint operating system) with a built-in cellular phone. Using the cellular phone capability, the interface connects to remote databases and displays the schema information of the database chosen by the user. In response to gestures made by the user using the pen, the interface automatically generates queries and retrieves results. We use the 'universal relation' concept to aid in automatically generating queries based on the attributes chosen by the user. We provide a summary of the status of this interface, some implementation details and suggest some future directions.","PeriodicalId":88972,"journal":{"name":"Proceedings. IEEE Workshop on Mobile Computing Systems and Applications","volume":"27 1","pages":"130-135"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74567595","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 : 1994-01-01DOI: 10.1109/MCSA.1994.512742
K. Cho, K.P. Birmans
Describes the design and implementation of a set of tools, called MobileChannel, for use with the Isis system. A simple scheme to support user mobility-switching a control point between replicated servers-provides a uniform mechanism to handle both client migrations and server failures. The hands-off mechanism is simplified by integrating a FIFO channel implementation into the server replication mechanism. Our scheme provides a simple abstraction of migration, practically eliminates hands-off protocols, provides fault tolerance, and is implemented within the existing group communication mechanisms of Isis.
{"title":"A group communication approach for mobile computing","authors":"K. Cho, K.P. Birmans","doi":"10.1109/MCSA.1994.512742","DOIUrl":"https://doi.org/10.1109/MCSA.1994.512742","url":null,"abstract":"Describes the design and implementation of a set of tools, called MobileChannel, for use with the Isis system. A simple scheme to support user mobility-switching a control point between replicated servers-provides a uniform mechanism to handle both client migrations and server failures. The hands-off mechanism is simplified by integrating a FIFO channel implementation into the server replication mechanism. Our scheme provides a simple abstraction of migration, practically eliminates hands-off protocols, provides fault tolerance, and is implemented within the existing group communication mechanisms of Isis.","PeriodicalId":88972,"journal":{"name":"Proceedings. IEEE Workshop on Mobile Computing Systems and Applications","volume":"47 1","pages":"95-102"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77733846","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 : 1994-01-01DOI: 10.1109/MCSA.1994.512743
M. Mazer, J. Tardo
Discusses a client-side-only approach to providing disconnected access to a heterogeneous set of network file services. Our method contrasts with those used in systems such as Coda, primarily because Coda depends upon changes to both the client software and the server software. Instead, we assume that we cannot make changes to the servers, and we explore the resultant benefits and limitations, as manifested in our prototype implementation. Unlike the LITTLE WORK approach to disconnected operation for the Andrew File System (AFS), we do not commit to a specific file access protocol; rather, we support access to multiple file services. We describe how a usability study affected our user model, system design and implementation.
{"title":"A client-side-only approach to disconnected file access","authors":"M. Mazer, J. Tardo","doi":"10.1109/MCSA.1994.512743","DOIUrl":"https://doi.org/10.1109/MCSA.1994.512743","url":null,"abstract":"Discusses a client-side-only approach to providing disconnected access to a heterogeneous set of network file services. Our method contrasts with those used in systems such as Coda, primarily because Coda depends upon changes to both the client software and the server software. Instead, we assume that we cannot make changes to the servers, and we explore the resultant benefits and limitations, as manifested in our prototype implementation. Unlike the LITTLE WORK approach to disconnected operation for the Andrew File System (AFS), we do not commit to a specific file access protocol; rather, we support access to multiple file services. We describe how a usability study affected our user model, system design and implementation.","PeriodicalId":88972,"journal":{"name":"Proceedings. IEEE Workshop on Mobile Computing Systems and Applications","volume":"17 1","pages":"104-110"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84312834","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 : 1994-01-01DOI: 10.1109/MCSA.1994.513482
M. Theimer, A. Demers, K. Petersen, M. Spreitzer, D. Terry, B. Welch
The paper describes a problem of weakly consistent replicated data systems used in support of disconnected groups of people. The problem concerns actions and updates derived from tentative data updates that are ultimately determined to be in conflict. While some such actions and updates can be automatically resolved, many require human intervention. Furthermore, although some file and database systems support internal conflict detection and resolution, derived actions may be external to those systems, implying that human users must ensure that proper consistency is maintained between independent components of the system. The entire problem becomes exacerbated when disconnected work groups are taken into account, where tentative data values may be seen and acted upon by multiple people.
{"title":"Dealing with tentative data values in disconnected work groups","authors":"M. Theimer, A. Demers, K. Petersen, M. Spreitzer, D. Terry, B. Welch","doi":"10.1109/MCSA.1994.513482","DOIUrl":"https://doi.org/10.1109/MCSA.1994.513482","url":null,"abstract":"The paper describes a problem of weakly consistent replicated data systems used in support of disconnected groups of people. The problem concerns actions and updates derived from tentative data updates that are ultimately determined to be in conflict. While some such actions and updates can be automatically resolved, many require human intervention. Furthermore, although some file and database systems support internal conflict detection and resolution, derived actions may be external to those systems, implying that human users must ensure that proper consistency is maintained between independent components of the system. The entire problem becomes exacerbated when disconnected work groups are taken into account, where tentative data values may be seen and acted upon by multiple people.","PeriodicalId":88972,"journal":{"name":"Proceedings. IEEE Workshop on Mobile Computing Systems and Applications","volume":"112 1","pages":"192-195"},"PeriodicalIF":0.0,"publicationDate":"1994-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87792907","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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