rahman khan - Academia.edu (original) (raw)
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Ensit : école nationale supérieure des ingénieurs de Tunis
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Papers by rahman khan
Proceedings of the 23rd SIGSPATIAL International Conference on Advances in Geographic Information Systems - GIS '15, 2015
We introduce a new type of spatial query, Optimal Accessible Location (OAL) query. When a set of ... more We introduce a new type of spatial query, Optimal Accessible Location (OAL) query. When a set of paths is provided the query finds the best location from a set of locations that has the optimal accessibility from these paths. OAL queries have many applications such as the selection of the optimal location for a mobile facility such as a food truck or selection of a venue for an event. We exploit geometric properties and develop pruning techniques to eliminate unrelated path segments as well as locations. Our experimental results demonstrate that we provide a readily deployable solution for real-life applications.
Lecture Notes in Computer Science, 2014
Finding a convenient meeting point for a group is a common problem. For example, a group of users... more Finding a convenient meeting point for a group is a common problem. For example, a group of users may want to meet at a restaurant that minimizes the group's total travel distance. Such queries are called Group Nearest Neighbor (GNN) queries. Up to now, users have had to rely on an external party, typically a location service provider (LSP), for computing an optimal meeting point. This implies that users have to trust the LSP with their private locations. Existing techniques for private GNN queries either cannot resist sophisticated attacks or are computationally too expensive to be implemented on the popular platform of mobile phones. This paper proposes an algorithm to efficiently process private GNN queries. To achieve high efficiency we propose an approach that approximates a GNN with a high accuracy and is robust to attacks. Unlike methods based on obfuscation, our method does not require a user to provide an imprecise location and is in fact location oblivious. Our approach is based on a distributed secure sum protocol which requires only light weight computation. Our experimental results show that we provide a readily deployable solution for real life applications which can also be deployed for other geo-spatial queries and applications.
Bulletin of Materials Science, 1987
The electrical resistivity and temperature coefficient of resistance of potycrystalline holmium h... more The electrical resistivity and temperature coefficient of resistance of potycrystalline holmium hydride films, grown on glass slides, have been measured in vacuo. Experimental results show that the resistivity decreases with decreasing film thickness. The resistivity of 200/~ holmium dihydride film is less than that of the parent metal. The observed behaviour of the thickness dependence of the resistivity has been explained in terms of the structural phase change.
Proceedings of the 23rd SIGSPATIAL International Conference on Advances in Geographic Information Systems - GIS '15, 2015
We introduce a new type of spatial query, Optimal Accessible Location (OAL) query. When a set of ... more We introduce a new type of spatial query, Optimal Accessible Location (OAL) query. When a set of paths is provided the query finds the best location from a set of locations that has the optimal accessibility from these paths. OAL queries have many applications such as the selection of the optimal location for a mobile facility such as a food truck or selection of a venue for an event. We exploit geometric properties and develop pruning techniques to eliminate unrelated path segments as well as locations. Our experimental results demonstrate that we provide a readily deployable solution for real-life applications.
Lecture Notes in Computer Science, 2014
Finding a convenient meeting point for a group is a common problem. For example, a group of users... more Finding a convenient meeting point for a group is a common problem. For example, a group of users may want to meet at a restaurant that minimizes the group's total travel distance. Such queries are called Group Nearest Neighbor (GNN) queries. Up to now, users have had to rely on an external party, typically a location service provider (LSP), for computing an optimal meeting point. This implies that users have to trust the LSP with their private locations. Existing techniques for private GNN queries either cannot resist sophisticated attacks or are computationally too expensive to be implemented on the popular platform of mobile phones. This paper proposes an algorithm to efficiently process private GNN queries. To achieve high efficiency we propose an approach that approximates a GNN with a high accuracy and is robust to attacks. Unlike methods based on obfuscation, our method does not require a user to provide an imprecise location and is in fact location oblivious. Our approach is based on a distributed secure sum protocol which requires only light weight computation. Our experimental results show that we provide a readily deployable solution for real life applications which can also be deployed for other geo-spatial queries and applications.
Bulletin of Materials Science, 1987
The electrical resistivity and temperature coefficient of resistance of potycrystalline holmium h... more The electrical resistivity and temperature coefficient of resistance of potycrystalline holmium hydride films, grown on glass slides, have been measured in vacuo. Experimental results show that the resistivity decreases with decreasing film thickness. The resistivity of 200/~ holmium dihydride film is less than that of the parent metal. The observed behaviour of the thickness dependence of the resistivity has been explained in terms of the structural phase change.