Video from http://www.youtube.com/v/SlqwSc8J8NU

It has been over 20 days since 17-year-old Trayvon Martin was shot and killed with a 9mm pistol in his father’s gated community in Florida on February 26th. Walking home from the local convenience store where he bought Skittles and a can of iced tea, Trayvon was identified as “suspicious” by the leader of the community’s Neighborhood Watch, George Zimmerman. Trayvon Martin was African-American.

Zimmerman allegedly called 911 to report a suspicious person walking around in the neighborhood and was told by police to take no action, to which Zimmerman responded, ”These assholes always get away.”

Minutes later, there were reports of shots being fired. Witnesses have been emerging and have faced some difficulty in getting the police to record their full testimonies, but have noted hearing a cry of help from the boy just before shots were fired. The youngest witness who saw the shooting take place, a 13-year-old boy, is still struggling with what he saw and the fact that Zimmerman has not yet been arrested. Other witnesses are arguing that the police department tampered with witness evidence at the scene of the crime.

The Martin family sued the police department for access to the 911 tapes, which they finally had the chance to listen to late last week. The family claims that the tapes make it absolutely clear that the teen was pursued by Zimmerman and that Zimmerman was not acting in self defense. According to one witness who heard the cries for help:

“This was not self-defense. We heard no fighting, no wrestling, no punching. We heard a boy crying. As soon as the shot went off, it stopped, which tells me it was the child crying. If it had been Zimmerman crying, it wouldn’t have stopped. If you’re hurting, you’re hurting.

The family, witnesses, and commentators are noting the racial components to the case.

The police department recently turned over the case to the State’s Attorney’s Office. The family continues to search for justice in the killing of their son and brother.

Addressing failures in wireless sensor networks

Krasimira Kapitanova
University of Virginia

1:00pm Wednesday 28 March, 2012, ITE 325b, UMBC

Wireless sensor networks are now being used for a growing number of applications, from mission critical applications, including fire-fighting, emergency response, infrastructure monitoring, and medical application, to smart home applications, such as home automation, energy efficiency, and home security. These applications must operate reliably and continuously due to the high costs associated with system failure and maintenance. However, continuous and reliable operation of sensor networks is notoriously difficult to guarantee due to hardware degradation and environmental changes, which can cause operating conditions that were impossible for the original system designers to foresee. Recent studies have found that low-cost sensors suffer from many types of faults. Inexpensive nodes can break and battery-powered nodes lose power. Furthermore, sensor network installations suffer from a large number of non-fail-stop faults in which the sensor does not completely fail. Instead, it continues to report values, but the meaning of the values changes or becomes invalid. This talk will discuss a number of new run-time techniques that use application-level semantics to detect, assess, and adapt to sensor node failures.

Krasimira Kapitanova is a PhD candidate of Computer Science at the University of Virginia. Her research focuses on wireless sensor network, in particular using formal approaches for event description and detection. She is also interested in how testing and machine learning techniques can be used to improve the reliability of sensor network applications.

Host: Tim Finin

Full Title: UMBC Falls to Rhode Island, 9-1, on Third Day of UMBC Spring Classic

Suffix trees for very large strings

Dr. Marina Barsky
University of Illinois at Urbana-Champaign

1:00pm Friday, 30 March 2012, ITE 325b, UMBC

The seminar is dedicated to the construction of suffix trees in external memory. A suffix tree is a compact index of all substrings of a given text. While being asymptotically linear in the size of the input, in practice, suffix trees can easily be 50 times larger than the input. As such, suffix trees often exceed typical main memory sizes, even when the input does not. As most existing algorithms are designed for RAM, their performance severely degrades when the tree and/or input do not fit in main memory. So far, this has prevented the wide application of suffix trees for the analysis of massive string collections.

We will look at new advanced methods of suffix tree construction which circumvent memory concerns and allow us to construct suffix trees for inputs of any size using secondary storage (magnetic disks). We will also discuss how this disk-based index can be used for facilitating the pattern discovery in sequential data.

Dr. Marina Barsky is currently a Post-Doctoral fellow in the Department of Computer Science at the University of Illinois at Urbana-Champaign, IL. She received her PhD in Computer Science from the University of Victoria, British Columbia, Canada in 2010. A large part of her post-graduate research was dedicated to pattern discovery in string data, primarily in massive DNA databases. She is currently expanding her expertise in database systems to new areas such as index management and data mining. Her research interests include data mining of sequential data, information networks, and teaching of computer science through interactive interfaces.

Host: Richard Chang

viviandnguyen:

One and a half songs of fun. at UMBC. (March)

This was a great night!

UMBC students from  SOCY/HAPP 354, “The Social Basis of Community and Public Health,” regularly visit Baltimore’s Port Discovery Children’s Museum to discuss health issues with young visitors (ages 2-10) and their families. This semester, the students shared public health messages at Port Discovery’s March 3rd “Healthy First Saturday” (photos now online).

The course, taught by Andrea Kalfoglou, is part of UMBC’s Health Administration and Policy Program. It explores the history, major concepts and practice of public health in the U.S and abroad. Students also learn about health disparities and how government, the private sector, NGOs and social entrepreneurs address public health needs.