Institute for Systems Research Technical Reports
Permanent URI for this collectionhttp://hdl.handle.net/1903/4376
This archive contains a collection of reports generated by the faculty and students of the Institute for Systems Research (ISR), a permanent, interdisciplinary research unit in the A. James Clark School of Engineering at the University of Maryland. ISR-based projects are conducted through partnerships with industry and government, bringing together faculty and students from multiple academic departments and colleges across the university.
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Item Image Browsers: Taxonomy, Guidelines, and Informal Specifications(1994) Plaisant, Catherine; Carr, David A.; Shneiderman, Ben; ISR; CSHCNImage browsing is necessary in numerous applications. Designers have merely used two one-dimensional scroll bars or they have made ad hoc designs for a two-dimensional scroll bar. However, the complexity of two-dimensional browsing suggests that more careful analysis, design, and evaluation might lead to significant improvements. We present a task taxonomy for image browsing, suggest design features and guidelines, assess existing strategies, and introduce an informal specificationItem Data Structures for Dynamic Queries: An Analytical and Experimental Evaluation(1994) Jain, Vinit; Shneiderman, Ben; ISRDynamic Queries is a querying technique for doing range search on multi-key data sets. It is a direct manipulation mechanism where the query is formulated using graphical widgets and the result s are displayed graphically preferably within 100 milliseconds.This paper evaluates four data structures, the multilist, the grid file, k-d tree and the quad tree used to organize data in high speed storage for dynamic queries. The effect of factors like size, distribution and dimensionality of data on the storage overhead and the speed of search is explored. Analytical models for estimating the storage and the search overheads are presented, and verified to be correct by empirical data. Results indicate that multilists are suitable for small (few thousand points) data sets irrespective of the data distribution. For large data sets the grid files are excellent for uniformly distributed data, and trees are good for skewed data distributions. There was no significant difference in performance between the tree structures.
Item Next Generation Network Management Technology(1994) Atallah, George C.; Ball, Michael O.; Baras, John S.; Goli, Shravan K.; Karne, Ramesh K.; Kelley, Stephen; Kumar, Harsha P.; Plaisant, Catherine; Roussopoulos, Nick; Shneiderman, Ben; Srinivasarao, Mulugu; Stathatos, Kostas; Teittinen, Marko; Whitefield, David; ISR; CSHCNToday's telecommunications networks are becoming increasingly large, complex, mission critical and heterogeneous in several dimensions. For example, the underlying physical transmission facilities of a given network may be ﲭixed media (copper, fiber- optic, radio, and satellite); the sub networks may be acquired from different vendors due to economic, performance, or general availability reasons; the information being transmitted over the network may be ﲭultimedia (video, data, voice, and images) and, finally, varying performance criteria may be imposed e.g. data transfer may require high throughput while the others, whose concern is voice communications, may require low call blocking probability. For these reasons, future telecommunications networks are expected to be highly complex in their services and operations. Due to this growing complexity and the disparity among management systems for individual sub networks, efficient network management systems have become critical to the current and future success of telecommunications companies. This paper addresses a research and development effort which focuses on prototyping configuration management, since that is the central process of network management and all other network management functions must be built upon it. Our prototype incorporates ergonomically designed graphical user interfaces tailored to the network configuration management subsystem and to the proposed advanced object-oriented database structure. The resulting design concept follows open standards such as Open Systems Interconnection (OSI) and incorporates object oriented programming methodology to associate data with functions, permit customization, and provide an open architecture environment.- A revised version of this technical report has been published in
The 12th Symposium on Space Nuclear Power and Propulsion/Commercialization, pp. 75-82, Albuquerque, NM, January 8-12, 1995.Item Data Structures for Dynamic Queries: An Analytical and Experimental Evaluation(1993) Jian, Vinit; Shneiderman, Ben; ISRDynamic Queries is a querying technique for doing range search on multi-keydata sets. It is a direct manipulation mechanism where the query is formulatedusing graphical widgets and the results are displayed graphically in real time.This paper evaluates four data structures, the multilist, the gridfile, k-d tree and the quad tree used to organize data in high speed storage for dynamic queries. The effect of factors like size, distribution and dimensionality of data on the storage overhead and the speed of search is explored. A way of estimating the storage and the search overheads using analytical models is presented. These models are verified to be correct by empirical data.
Results indicate that multilists are suitable for small (few thousandpoints) data sets irrespective of the data distribution. For large data sets the grid files are excellent for uniformly distributed data, and trees are good for skewed data distributions. These was no significant difference in performance between the tree structures.