EDGE newsletters contain brief descriptions of research activities and discoveries at Virginia Polytechnic Institute and State University and provides links to researchers, centers, and sources of additional information.

One-stop social service

Citizens collecting benefits must often visit several offices to receive the benefits to which they are entitled. The process can prevent individuals from devoting adequate time to enhancing their prospects for becoming self-supporting with a consequent harmful impact on their health.

A major problem is that isolated and autonomous information systems are hard to interoperate.

Computer science researchers from Virginia Tech’s Northern Virginia Center and Purdue University teamed with the Indiana Family and Social Services Administration and U.S. Health and Human Services to help citizens better access benefits.

A significant technical challenge was incompatibility between various databases created using different software and mounted on different hardware platforms. The researchers provided systems solutions and created Web access based on database content, such as grouping law enforcement information into one ontology and child welfare databases in another.

The result is a one-stop-shop to access hundreds of databases used for Social Services Administration. Social workers are able to access all necessary information using one single interface so that citizens in need of help are able to have most of their needs satisfied in a single meeting.

Contact Dr. Athman Bouguettaya of Virginia Tech at athman@vt.edu.

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Communicating across 10 time zones

Hughes Network Systems, a contractor providing mobile phone service via a satellite for customers of Thuraya Satellite Telecommunications Company, found it challenging to serve widely dispersed and mobile customers. The satellite is in a fixed orbit that covers 10 time zones from Spain to India. Some areas are heavily populated, while other areas are sparsely populated.

Each mobile phone can communicate with the satellite or through a ground station. The satellite capacity is 13,750 simultaneously usable telephone channels. The coverage area is divided geographically into 250 cells, and channels are allocated dynamically to the cells.

The challenge is that a channel cannot simply be removed from one cell and given to another at any time. Important constraints must be met and demand in each cell must be predicted based on population, customer base, and time of day, so that 1) the necessary channels are allocated to a cell before the demand, and 2) no more than 2 percent of attempted calls are denied because of too few channels.

Computer science faculty member Lenwood Heath, consulting with Hughes employee and former student Xiangdong Liu, addressed the difficulty of allocating sufficient channels during peak cell usage while providing adequate service across all 10 time zones.

The researchers employed an algorithmic strategy called simulated annealing to solve the channel assignment problem. “We expressed the problem as an optimization problem with numerous constraints,” says Heath. “We were able to solve the optimization problem and take into account more constraints than in any previous work done by satellite engineers.”

Hughes has applied for a patent on the developed technique.

Contact Dr. Heath at 540-231-4352 or heath@vt.edu.

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Improved packaging provides longer shelf life

Shredded cheeses are more convenient, but can spoil before they are used.

Virginia Tech faculty members in food science and technology conducted extensive experiments to define the packaging and processing conditions needed to provide an acceptable product with the longest shelf life possible. Research focused on modified atmosphere packaging (MAP) and examined the use of approved food additives to control mold spoilage on shredded cheeses. The research led to recommendations on optimal MAP procedures and additive use, which are being adopted by the U.S. cheese industry.

Implementation of proper MAP packaging for shredded cheeses has markedly decreased the spoilage rate of cheeses at both the institutional and consumer level. Use of anti-mold additives also holds great promise for increasing the shelf life of shredded cheeses and other dairy products.

Contact Dr. Joe Marcy at 540-231-7850 or jmarcy@vt.edu.

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