Managing public key certificates revocation has long been a central issue in public key infrastructures. Though various certificate revocation mechanisms have been proposed to address this issue, little effort has been devoted to the empirical analysis of real-world certificate revocation data. In this paper, we conduct such an empirical analysis based on a large amount of data collected from V...

The space-time scan statistic is a widely-used method for cluster detection in which both the geographic locations and the temporal length of the cluster are unknown. It relies on a cylinder scanning window in which the base represents geographic locations and the height represents the time component, simultaneously. Due to the strict shape of the scanning window, different geometries and graph...

Drug-dosing recommendations for visceral leishmaniasis (VL) treatment are based on the patients' weight or age. A current lack of demographic and anthropometric data on patients hinders (1) the ability of health providers to properly prepare for patient management, (2) an informed drug procurement for disease control, and (3) the design of clinical trials and development of new drug therapies i...

Location-based Mobile Social Networks (MSNs) are becoming increasingly popular given the success of Online Social Networks (OSNs), such as Facebook and MySpace, and recent availability of GPS-embedded mobile platforms, such as Apple iPhones and Google Android phones. MSNs extend existing OSNs by allowing a user to know where her friends are and to meet new people nearby who share her interests....

The use of geographic information systems in determining transit service areas has not progressed far beyond simple buffering operations even though there is widespread capability to analyze network walking distances in conjunction with demographic, cadastral, and land-use data sets. This article presents a method for determining the population with walking access to bus stop locations using th...

How do organizations coordinate interdependent activities across geographic distance? We analyze 121 surveys of offshored processes to understand both the sources of difficulty in the remote delivery of services as well as how organizations overcome these difficulties. We find that contrary to conventional wisdom, system dependence of a process is a much greater hindrance to the offshoring serv...

BACKGROUND Veterans of the 1991 Gulf War have an increased risk of amyotrophic lateral sclerosis (ALS), but the etiology is unknown. OBJECTIVES This study sought to identify geographic areas with elevated risk for the later development of ALS among military personnel who served in the first Gulf War. METHODS A unified geographic information system (GIS) was constructed to allow analysis of ...

Location-based services have attracted the attention of important research in the field of mobile computing. Specifically, different mechanisms have been proposed to process location-dependent queries. In the above mentioned context, it is usually assumed that the location data are expressed at a fine geographic precision. However, a different granularity may be more appropriate in certain situ...

BACKGROUND The fall peak in childhood asthma exacerbations is thought to be related to an increase in viral infections and allergen exposure when children return to school. Whether the seasonality of asthma attacks among children from different geographic regions follows similar trends is unclear. OBJECTIVE To compare seasonal trends in asthma exacerbations among school-age children who lived...

Advances in human dynamics research and availability of geo-referenced communication data provide an unprecedented opportunity for studying the semantics of communication and understanding the interplay between online social networks and geography. Among the most extensively studied topics in geographically-embedded communication networks, are the effect of geographic proximity on interpersonal...