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The purpose of this paper is to generate information about the contours of police responsiveness, focussing on how quickly and precisely police make firearm arrests after a shooting incident.

Using a modified version of the Knox close pair method, a spatio-temporal clustering technique, over 11,000 shooting incidents and firearm arrests between 2004 and 2007 in Philadelphia, PA were analyzed.

Police are responding quickly and in a geographically targeted fashion to shootings. Across Philadelphia elevated patterns of firearm arrests were approximately two and a half times greater than would be expected if shootings and firearm arrests lacked a spatio-temporal association. Greater than expected patterns of firearm arrests persisted for roughly one-fourth of a mile and for about one week from the shooting incident but the strength of these associations waned over space and time. The pattern of police response varied slightly across different police divisions.

The current method uncovered spatio-temporal patterning and determined when these patterns were significantly different from what would be expected if the events were completely independent. Specific events and processes surrounding each event are not known.

Findings can help inform the knowledge about police behavior in terms of how police produce arrests.

The patterns observed here provide more micro-level detail than has been revealed in previous studies regarding police responsiveness to firearm violence while also introducing a more integrated spatially and temporally specific framework.

The increasing need to access and elaborate dynamic and heterogeneous information sources distributed over the Internet calls for new models and paradigms for application design and development. The mobile agent paradigm promotes the design of applications where agents roam through Internet sites to locally access and elaborate information and resources, possibly co‐operating with each other. Focuses on mobile agent co‐ordination, and presents the TuCSoN co‐ordination model for Internet applications based on mobile information agents. TuCSoN exploits a notion of local tuple‐based interaction space, called a tuple centre. A tuple centre is a tuple space enhanced with the capability of programming its behaviour in response to communication events. This enables properties to be embedded into the interaction space, and a mobile agent to be designed independently of the peculiarities of the information sources. Several issues critical to Internet applications can then be charged on tuple centres transparently to agents. The effectiveness of the TuCSoN model is first shown by means of an application example in the area of Internet information retrieval, then discussed in the context of workflow management and electronic commerce.