The Experts below are selected from a list of 14904 Experts worldwide ranked by ideXlab platform
José A.b. Fortes - One of the best experts on this subject based on the ideXlab platform.
-
Seamless Access to Decentralized Storage Services in Computational Grids via a Virtual File System
Cluster Computing, 2004Co-Authors: Renato J. Figueiredo, Nirav Kapadia, José A.b. FortesAbstract:This paper describes a novel technique for establishing a virtual file system that allows data to be transferred user-transparently and on-demand across computing and storage servers of a computational grid. Its implementation is based on extensions to the Network File System (NFS) that are encapsulated in software proxies. A key differentiator between this approach and previous work is the way in which file servers are partitioned: while conventional file systems share a single (logical) server across multiple users, the virtual file system employs multiple proxy servers that are created, customized and terminated dynamically, for the duration of a computing session, on a per-user basis. Furthermore, the solution does not require modifications to standard NFS clients and servers. The described approach has been deployed in the context of the PUNCH network-computing infrastructure, and is unique in its ability to integrate unmodified, interactive applications (even commercial ones) and existing computing infrastructure into a network computing environment. Experimental results show that: (1) the virtual file system performs well in comparison to native NFS in a local-area setup, with mean overheads of 1 and 18%, for the single-client execution of the Andrew benchmark in two representative computing environments, (2) the average overhead for eight clients can be reduced to within 1% of native NFS with the use of concurrent proxies, (3) the wide-area performance is within 1% of the local-area performance for a typical compute-intensive PUNCH application (SimpleScalar), while for the I/O-intensive application Andrew the wide-area performance is 5.5 times worse than the local-area performance.
-
Seamless Access to Decentralized Storage Services in Computational Grids via a Virtual File System
Cluster Computing, 2004Co-Authors: Renato J. Figueiredo, Nirav Kapadia, José A.b. FortesAbstract:This paper describes a novel technique for establishing a virtual file system that allows data to be transferred user-transparently and on-demand across computing and storage servers of a computational grid. Its implementation is based on extensions to the Network File System (NFS) that are encapsulated in software proxies. A key differentiator between this approach and previous work is the way in which file servers are partitioned: while conventional file systems share a single (logical) server across multiple users, the virtual file system employs multiple proxy servers that are created, customized and terminated dynamically, for the duration of a computing session, on a per-user basis. Furthermore, the solution does not require modifications to standard NFS clients and servers. The described approach has been deployed in the context of the PUNCH network-computing infrastructure, and is unique in its ability to integrate unmodified, interactive applications (even commercial ones) and existing computing infrastructure into a network computing environment. Experimental results show that: (1) the virtual file system performs well in comparison to native NFS in a local-area setup, with mean overheads of 1 and 18%, for the single-client execution of the Andrew benchmark in two representative computing environments, (2) the average overhead for eight clients can be reduced to within 1% of native NFS with the use of concurrent proxies, (3) the wide-area performance is within 1% of the local-area performance for a typical compute-intensive PUNCH application (SimpleScalar), while for the I/O-intensive application Andrew the wide-area performance is 5.5 times worse than the local-area performance.
-
The PUNCH virtual file system: Seamless Access to decentralized storage services in a computational grid
Proceedings 10th IEEE International Symposium on High Performance Distributed Computing, 2001Co-Authors: Renato J. Figueiredo, N.h. Kapadia, José A.b. FortesAbstract:Describes a virtual file system that allows data to be transferred on demand between storage and computational servers for the duration of a computing session. The solution works with unmodified applications (even commercial ones) running on standard operating systems and hardware. The virtual file system employs software proxies to broker transactions between standard NFS (Network File System) clients and servers; the proxies are dynamically configured and controlled by computational grid middleware. The approach has been implemented and extensively exercised in the context of PUNCH (Purdue University Network Computing Hubs), an operational computing portal that has more than 1,500 users across 24 countries. The results show that the virtual file system performs well in comparison to native NFS: performance analyses show that the proxy incurs mean overheads of 1% and 18% with respect to native NFS for a single-client execution of the Andrew benchmark in two representative computing environments, and that the average overhead for eight clients can be reduced to within 1% of native NFS with concurrent proxies.
Renato J. Figueiredo - One of the best experts on this subject based on the ideXlab platform.
-
Seamless Access to Decentralized Storage Services in Computational Grids via a Virtual File System
Cluster Computing, 2004Co-Authors: Renato J. Figueiredo, Nirav Kapadia, José A.b. FortesAbstract:This paper describes a novel technique for establishing a virtual file system that allows data to be transferred user-transparently and on-demand across computing and storage servers of a computational grid. Its implementation is based on extensions to the Network File System (NFS) that are encapsulated in software proxies. A key differentiator between this approach and previous work is the way in which file servers are partitioned: while conventional file systems share a single (logical) server across multiple users, the virtual file system employs multiple proxy servers that are created, customized and terminated dynamically, for the duration of a computing session, on a per-user basis. Furthermore, the solution does not require modifications to standard NFS clients and servers. The described approach has been deployed in the context of the PUNCH network-computing infrastructure, and is unique in its ability to integrate unmodified, interactive applications (even commercial ones) and existing computing infrastructure into a network computing environment. Experimental results show that: (1) the virtual file system performs well in comparison to native NFS in a local-area setup, with mean overheads of 1 and 18%, for the single-client execution of the Andrew benchmark in two representative computing environments, (2) the average overhead for eight clients can be reduced to within 1% of native NFS with the use of concurrent proxies, (3) the wide-area performance is within 1% of the local-area performance for a typical compute-intensive PUNCH application (SimpleScalar), while for the I/O-intensive application Andrew the wide-area performance is 5.5 times worse than the local-area performance.
-
Seamless Access to Decentralized Storage Services in Computational Grids via a Virtual File System
Cluster Computing, 2004Co-Authors: Renato J. Figueiredo, Nirav Kapadia, José A.b. FortesAbstract:This paper describes a novel technique for establishing a virtual file system that allows data to be transferred user-transparently and on-demand across computing and storage servers of a computational grid. Its implementation is based on extensions to the Network File System (NFS) that are encapsulated in software proxies. A key differentiator between this approach and previous work is the way in which file servers are partitioned: while conventional file systems share a single (logical) server across multiple users, the virtual file system employs multiple proxy servers that are created, customized and terminated dynamically, for the duration of a computing session, on a per-user basis. Furthermore, the solution does not require modifications to standard NFS clients and servers. The described approach has been deployed in the context of the PUNCH network-computing infrastructure, and is unique in its ability to integrate unmodified, interactive applications (even commercial ones) and existing computing infrastructure into a network computing environment. Experimental results show that: (1) the virtual file system performs well in comparison to native NFS in a local-area setup, with mean overheads of 1 and 18%, for the single-client execution of the Andrew benchmark in two representative computing environments, (2) the average overhead for eight clients can be reduced to within 1% of native NFS with the use of concurrent proxies, (3) the wide-area performance is within 1% of the local-area performance for a typical compute-intensive PUNCH application (SimpleScalar), while for the I/O-intensive application Andrew the wide-area performance is 5.5 times worse than the local-area performance.
-
The PUNCH virtual file system: Seamless Access to decentralized storage services in a computational grid
Proceedings 10th IEEE International Symposium on High Performance Distributed Computing, 2001Co-Authors: Renato J. Figueiredo, N.h. Kapadia, José A.b. FortesAbstract:Describes a virtual file system that allows data to be transferred on demand between storage and computational servers for the duration of a computing session. The solution works with unmodified applications (even commercial ones) running on standard operating systems and hardware. The virtual file system employs software proxies to broker transactions between standard NFS (Network File System) clients and servers; the proxies are dynamically configured and controlled by computational grid middleware. The approach has been implemented and extensively exercised in the context of PUNCH (Purdue University Network Computing Hubs), an operational computing portal that has more than 1,500 users across 24 countries. The results show that the virtual file system performs well in comparison to native NFS: performance analyses show that the proxy incurs mean overheads of 1% and 18% with respect to native NFS for a single-client execution of the Andrew benchmark in two representative computing environments, and that the average overhead for eight clients can be reduced to within 1% of native NFS with concurrent proxies.
Sudha Krishnamurthy - One of the best experts on this subject based on the ideXlab platform.
-
tinysip providing Seamless Access to sensor based services
International Conference on Mobile and Ubiquitous Systems: Networking and Services, 2006Co-Authors: Sudha KrishnamurthyAbstract:Recent technological trends are transforming sensor nodes from passive data-gathering entities to a collaborative network of sensors, capable of providing data-related and event-related information services. Such a sensor-based information service is useful only if it cain be Seamlessly Accessed across traditional networks and through familiar device interfaces. In order to enable such ubiquitous Access to sensor-based services, we need a remote messaging protocol that supports versatile messaging options, interoperates over different types of network, and allows messages to be routed based on flexible attribute-based addressing of endpoints. Furthermore, in order to ensure ease of adoption and deployment within an enterprise as well as in consumer environments, we must leverage communication abstractions that are well-known and already supported on traditional networks. In this paper, we propose TinySIP as a communication abstraction for Accessing sensor-based services. TinySIP is based on the Session Initiation Protocol (SIP), which is a standard application-level signaling mechanism. Users on traditional networks remotely interact with a sensor network service by sending SIP messages. A gateway maps the SIP abstractions to the corresponding TinySIP abstractions and propagates the messages to the sensor nodes. We are currently planning on deploying the SIP-based solution that we propose on a research testbed to enable users on a wireless mesh to Access the in-network storage and event correlation services offered by a sensor network consisting of 20 MicaZ sensor nodes.
-
MobiQuitous - TinySIP: Providing Seamless Access to Sensor-based Services
2006 Third Annual International Conference on Mobile and Ubiquitous Systems: Networking & Services, 2006Co-Authors: Sudha KrishnamurthyAbstract:Recent technological trends are transforming sensor nodes from passive data-gathering entities to a collaborative network of sensors, capable of providing data-related and event-related information services. Such a sensor-based information service is useful only if it cain be Seamlessly Accessed across traditional networks and through familiar device interfaces. In order to enable such ubiquitous Access to sensor-based services, we need a remote messaging protocol that supports versatile messaging options, interoperates over different types of network, and allows messages to be routed based on flexible attribute-based addressing of endpoints. Furthermore, in order to ensure ease of adoption and deployment within an enterprise as well as in consumer environments, we must leverage communication abstractions that are well-known and already supported on traditional networks. In this paper, we propose TinySIP as a communication abstraction for Accessing sensor-based services. TinySIP is based on the Session Initiation Protocol (SIP), which is a standard application-level signaling mechanism. Users on traditional networks remotely interact with a sensor network service by sending SIP messages. A gateway maps the SIP abstractions to the corresponding TinySIP abstractions and propagates the messages to the sensor nodes. We are currently planning on deploying the SIP-based solution that we propose on a research testbed to enable users on a wireless mesh to Access the in-network storage and event correlation services offered by a sensor network consisting of 20 MicaZ sensor nodes.
Na Li - One of the best experts on this subject based on the ideXlab platform.
-
a responsive design approach for supporting mobile Access to virtual and remote laboratories
International Conference on Advanced Learning Technologies, 2014Co-Authors: Panagiotis Zervas, Alexandros Trichos, Demetrios G Sampson, Na LiAbstract:Remote and virtual laboratories aim to overcome typical constraints of traditional laboratories and offer Access to laboratory experiments without location and time restrictions. Additionally, the continuous growth of mobile devices' ownership, as well as their increased technical capabilities, have created an emerging trend for supporting mobile Access to virtual and remote labs. Existing approaches in this direction are focusing on developing device-dependent mobile apps for Accessing the experiment(s) of the original remote or virtual lab. This creates difficulties related to (a) Seamless Access to experiments of remote or virtual labs across various mobile devices and (b) additional costs that are needed for developing different versions of the same mobile app that meets the specific technical requirements of each mobile device. In this paper, we aim to address this issue by adopting a responsive design approach for developing mobile web apps towards providing Seamless Access through various mobile devices to existing virtual and remote labs.
Nirav Kapadia - One of the best experts on this subject based on the ideXlab platform.
-
Seamless Access to Decentralized Storage Services in Computational Grids via a Virtual File System
Cluster Computing, 2004Co-Authors: Renato J. Figueiredo, Nirav Kapadia, José A.b. FortesAbstract:This paper describes a novel technique for establishing a virtual file system that allows data to be transferred user-transparently and on-demand across computing and storage servers of a computational grid. Its implementation is based on extensions to the Network File System (NFS) that are encapsulated in software proxies. A key differentiator between this approach and previous work is the way in which file servers are partitioned: while conventional file systems share a single (logical) server across multiple users, the virtual file system employs multiple proxy servers that are created, customized and terminated dynamically, for the duration of a computing session, on a per-user basis. Furthermore, the solution does not require modifications to standard NFS clients and servers. The described approach has been deployed in the context of the PUNCH network-computing infrastructure, and is unique in its ability to integrate unmodified, interactive applications (even commercial ones) and existing computing infrastructure into a network computing environment. Experimental results show that: (1) the virtual file system performs well in comparison to native NFS in a local-area setup, with mean overheads of 1 and 18%, for the single-client execution of the Andrew benchmark in two representative computing environments, (2) the average overhead for eight clients can be reduced to within 1% of native NFS with the use of concurrent proxies, (3) the wide-area performance is within 1% of the local-area performance for a typical compute-intensive PUNCH application (SimpleScalar), while for the I/O-intensive application Andrew the wide-area performance is 5.5 times worse than the local-area performance.
-
Seamless Access to Decentralized Storage Services in Computational Grids via a Virtual File System
Cluster Computing, 2004Co-Authors: Renato J. Figueiredo, Nirav Kapadia, José A.b. FortesAbstract:This paper describes a novel technique for establishing a virtual file system that allows data to be transferred user-transparently and on-demand across computing and storage servers of a computational grid. Its implementation is based on extensions to the Network File System (NFS) that are encapsulated in software proxies. A key differentiator between this approach and previous work is the way in which file servers are partitioned: while conventional file systems share a single (logical) server across multiple users, the virtual file system employs multiple proxy servers that are created, customized and terminated dynamically, for the duration of a computing session, on a per-user basis. Furthermore, the solution does not require modifications to standard NFS clients and servers. The described approach has been deployed in the context of the PUNCH network-computing infrastructure, and is unique in its ability to integrate unmodified, interactive applications (even commercial ones) and existing computing infrastructure into a network computing environment. Experimental results show that: (1) the virtual file system performs well in comparison to native NFS in a local-area setup, with mean overheads of 1 and 18%, for the single-client execution of the Andrew benchmark in two representative computing environments, (2) the average overhead for eight clients can be reduced to within 1% of native NFS with the use of concurrent proxies, (3) the wide-area performance is within 1% of the local-area performance for a typical compute-intensive PUNCH application (SimpleScalar), while for the I/O-intensive application Andrew the wide-area performance is 5.5 times worse than the local-area performance.
