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ABSTRACT: A geographic information system is often used to find objects of users' interest. It presents the users with an interface. Typically, a user interface presents a language for communication. We propose a prototype of a high level interface based on simplified relational algebra. A prototype system has been proposed. It is based on the notion of a query-by-object (QBO) approach.
Frontier of Computer Science and Technology, 2007. FCST 2007. Japan-China Joint Workshop on; 12/2007
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ABSTRACT: The use of handheld devices, such as cell phones, PDAs or pocket computers as tools for querying spatial data in mobile environments, is becoming increasingly popular. Thus, there is a need for simple and user-friendly interfaces to allow users to pose adhoc queries. At present, Query-By-Example (QBE) is available as a user-friendly interface, developed for accessing a RDBMS on a desktop computer. In this paper, we propose extensions for QBE to support spatial queries on mobile devices. It is accordingly named as Spatial mQBE (m stands for mobile). An empirical study shows that Spatial mQBE is a simple and an intuitive interface which facilitates the dynamic expression of both spatial and common database queries. The main strengths of this interface are its simplicity to express a query and its expressive power
Computer and Information Technology, 2006. CIT '06. The Sixth IEEE International Conference on; 10/2006
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ABSTRACT: Many applications use geographic data, such as land management, urban planning, tourism, vehicle guidance and navigation, and e-commerce. A related research problem is to define user-friendly interfaces for Web GIS. There is a need for the definition of simple and user-friendly interfaces to allow the users to pose ad-hoc queries. Query-by-example (QBE) is a user-friendly language developed for a RDBMS. However, many RDBMS have included support for spatial extensions in SQL. QBE has not been extended in line with these extensions. In this paper, we make an effort to create extensions for QBE to support spatial queries and thus calling it spatial QBE. We show that spatial QBE is a simple and user-friendly interface for Web users. It can cater to both spatial and common database queries. The main strengths of this interface are its simplicity to express a query and its expressive power.
Computer and Information Technology, 2005. CIT 2005. The Fifth International Conference on; 10/2005
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ABSTRACT: In the last few years, many GIS applications have appeared on the Web giving users access to both spatial and non-spatial (attribute) data. Web access to GIS resources needs to address the possibility of access via handheld devices such as mobile phones, PDAs or pocket computers. Currently, only a few research studies are available on high-level user interface for spatial queries on such devices. Thus, an important research problem is to design user-friendly interfaces for mobile Web GIS. Query-by-example (QBE) is a user-friendly language developed for a relational database management system (RDBMS). Many RDBMSs have included support for spatial extensions. In this paper, we make an effort to create extensions for QBE to support spatial queries on mobile devices. It is called spatial mQBE. We show that spatial mQBE is a simple and user-friendly interface. The main strengths of this interface are its simplicity to express a query and its expressive power.
Web Intelligence, 2005. Proceedings. The 2005 IEEE/WIC/ACM International Conference on; 10/2005
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ABSTRACT: Information requirement elicitation (IRE) is essential in wireless Web service to elicit information requirements through interactive choice prompts. We present a high-level user interface for an IRE-enabled information system, in the context of database queries by a mobile Web user. The prototype is based on the notion of a query-by-object (QBO) approach of building a query using multiple user-level steps. The test prototype system uses the mobile information devices profile (MIDP) of the Java 2 Platform, Micro Edition (J2ME), for a wireless front end, and a Java 2 Platform, Enterprise Edition (J2EE) application server and an object-relational database management system (ORDBMS) at the back end. A sample set of dynamic queries demonstrates ease of use by the users.
Mobile Business, 2005. ICMB 2005. International Conference on; 08/2005
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ABSTRACT: Nowadays, a major activity on the Internet is the retrieval and browsing of multimedia information. Yet, today 's search engines are not really up to the task. Users often have to query various search engines and browse many Web sites before finding a satisfactory answer. Once users find such an answer, presentation of the results is very rigid, i.e., not tailored to the users' needs, and it does not enable users to manipulate the data. Thus, this retrieval activity often becomes tedious. To improve user-information interaction, a major issue is to give search-engines the ability to access data semantics. We propose a framework to address the issue. Our framework combines database and multimedia data mining to endow Web-based applications with the ability to let users manipulate the data at different levels of interest. As an experimental testbed, we implemented a holiday planner that supports users in their search for a hotel. By using database technology, Web-based multimedia interaction becomes possible, offering as a side effect more feasible and reliable feedback.
Web Intelligence, 2003. WI 2003. Proceedings. IEEE/WIC International Conference on; 11/2003
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ABSTRACT: A model of asynchronous transaction management has been proposed in this study. This model demonstrates a procedure for elimination of delays caused by the occurrence of distributed deadlocks. The possibilities of occurrence of deadlocks are eliminated by using multiple asynchronous operations. By using the proposed model of activity, many conventional delays associated with transaction processing get eliminated prior to the occurrence of a wait state.
Parallel Processing Workshops, 2003. Proceedings. 2003 International Conference on; 11/2003
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ABSTRACT: Distributed locking is commonly adopted for performing concurrency control in distributed systems. It incorporates additional steps for handling deadlocks. This activity is carried out by methods based on wait-for-graphs or probes. The present study examines detection of conflicts based on enhanced local processing for distributed concurrency control. In the proposed "edge detection" approach, a graph-based resolution of access conflicts has been adopted. The technique generates a uniform wait-for precedence order at distributed sites for transactions to execute. The earlier methods based on serialization graph testing are difficult to implement in a distributed environment. The edge detection approach is a fully distributed approach. It presents a unified technique for locking and deadlock detection exercises. The technique eliminates many deadlocks without incurring message overheads.
IEEE Transactions on Knowledge and Data Engineering 06/2003; 15(3):721- 733. · 1.66 Impact Factor
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ABSTRACT: Many Web based information systems plan to support database query facilities for the Web users. This will enable the users to seek the desired information from vast data resources. However, most Web users are not skilled at using the conventional database query languages. Most users are highly skilled at referring to tabular data. A natural inclination exists among the users for object-by-object traction to find information. We propose an approach for the Web information systems users. The proposed interface introduces simplicity and avoids communication ambiguities.
TENCON '02. Proceedings. 2002 IEEE Region 10 Conference on Computers, Communications, Control and Power Engineering; 11/2002
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ABSTRACT: Data warehouses are used in many applications that depend on distributed systems. A data warehouse supports information processing by providing a single platform of integrated, historical data for doing analysis. Data warehouses provide the facility for integration in a world of unintegrated application systems. The contents of a data warehouse are evolved in an evolutionary, step-at-a-time fashion. A data warehouse organizes and stores the data needed for informational, analytical processing over a long historical time perspective. Data warehouses keep a materialized view (such as historical data), and user queries are processed using this view. The view has to be maintained to reflect the updates done against the base relations stored at the various distributed data sources. Detecting and extracting modifications from information sources is an integral part of a data warehouse. For unsophisticated sources, in practice it is often necessary to infer modifications by periodically comparing snapshots and backup copies of data from the source. This study considers the materialized view and its maintenance. Various implementation and performance evaluation of the differential snapshot algorithms have been compared for evaluation of suitable alternatives.
Parallel Processing Workshops, 2002. Proceedings. International Conference on; 02/2002
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S. Bhalla
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ABSTRACT: A number of factors contribute to delays in transaction execution. In a real-time database system, delays due to deadlocks, data accessing, and transaction commit must reduce to enable a transaction to complete successfully. In this report, a model of transaction execution is presented that permits execution and commit of any hard real-time transaction. The execution proceeds without the incidence of deadlock, or other blocking delays such as, due to denial of lock or commit approvals. The proposed technique is based on transaction classification and implementation of a precedence management scheme. The scheme provides an instantaneous execution opportunity to a serializable transaction within a hard real-time database system
High Performance Computing, 1998. HIPC '98. 5th International Conference On; 01/1999
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ABSTRACT: Distributed systems depend on consistent global snapshots for process recovery and garbage collection activity. We provide exact conditions for an arbitrary checkpoint based on independent dependency tracking within clusters of nodes. The method permits nodes (within clusters) to independently compute dependency information based on available (local) information. The existing models of global snapshot computations provide the necessary and sufficient conditions. But, these require expensive global computations. The proposed computations can be performed by a node to identify existing global checkpoints. The nodes can also compute conditions to make a checkpoint, or conditions, such that a collection of checkpoints, can belong to a global snapshot
High-Performance Computing, 1997. Proceedings. Fourth International Conference on; 01/1998
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ABSTRACT: Consistent recovery from process failures is an essential
component of reliable distributed systems. Many existing recovery
techniques use asynchronous message logging and checkpoints. Most of the
present approaches depend on logged states of non-fail processes for
recovery. A model of recovery based on the current active states of
processes has been proposed. The algorithm considers recoverable state
of the failed process and current states of the non-failed processes.
Each process recovers to a consistent system state independently
High Performance Computing, 1996. Proceedings. 3rd International Conference on; 01/1997
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ABSTRACT: Replicated data management systems adopt the 1-copy
serializability criteria for processing transactions. In order to
achieve this goal, many approaches rely on obtaining votes from other
sites for processing update requests. In the proposed approach, a
technique for generation of precedence graphs for each transaction
execution is analyzed. The transaction data flow graph approach is a
fully distributed approach. The proposed technique, is free from
deadlocks, and avoids resubmission of transactions
IEEE Transactions on Knowledge and Data Engineering 11/1995; · 1.66 Impact Factor
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ABSTRACT: Concurrency control based on conventional techniques requires
additional efforts for deadlock detection and elimination. The
possibility of a deadlock is also connected to the introduction of
delays, and repeated restarts of transactions in deadlock cycles. In the
proposed approach, a technique for generation of data flow precedence
graphs among transactions at data sites has been studied. The local
access graph approach is a fully distributed approach. Through local
computations, the approach can prevent deadlocks in a distributed system
Parallel Algorithms/Architecture Synthesis, 1995. Proceedings. First Aizu International Symposium on; 04/1995
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ABSTRACT: Distributed systems use optimistic message logging for recovery from transient process failures. Such a recovery is facilitated by asynchronous message logging and check-pointing. It is also supported by garbage collection which requires identifying messages in stable storage that are no longer needed for the process of recovery. For this purpose, it is necessary to keep track of message dependencies between process states. A model to keep track of state dependencies using dependency graphs has been proposed
Parallel Algorithms/Architecture Synthesis, 1995. Proceedings. First Aizu International Symposium on; 04/1995
