Fast activity detection indexing for temporal stochastic automaton based activity models
- 1. FAST ACTIVITY DETECTION INDEXING FOR TEMPORAL STOCHASTIC AUTOMATON-BASED ACTIVITY MODELS ABSTRACT: In this paper, we address the problem of efficiently detecting occurrences of high-level activities from such interleaved data streams. A solution to this important problem would greatly benefit a broad range of applications, including fraud detection, video surveillance, and cyber security. There has been extensive work in the last few years on modeling activities using probabilistic models. In this paper, we propose a temporal probabilistic graph so that the elapsed time between observations also plays a role in defining whether a sequence of observations constitutes an activity. We first propose a data structure called “temporal multiactivity graph” to store multiple activities that need to be concurrently monitored. We then define an index called Temporal Multiactivity Graph Index Creation (tMAGIC) that, based on this data structure, examines and links observations as they occur. We define algorithms for insertion and bulk insertion into the tMAGIC index and show that this can be efficiently accomplished. We define algorithms to solve two problems: the “evidence” problem that tries to find all occurrences of an activity (with probability over a threshold) within a given sequence of observations, and the “identification” problem that tries to find the activity that best matches a sequence of observations. We introduce complexity reducing restrictions and pruning strategies to make the problem-which is intrinsically exponential-linear to the number of observations. Our experiments confirm that tMAGI- has time and space complexity linear to the size of the input, and can efficiently retrieve instances of the monitored activities. ECWAY TECHNOLOGIES IEEE PROJECTS & SOFTWARE DEVELOPMENTS OUR OFFICES @ CHENNAI / TRICHY / KARUR / ERODE / MADURAI / SALEM / COIMBATORE CELL: +91 98949 17187, +91 875487 2111 / 3111 / 4111 / 5111 / 6111 VISIT: www.ecwayprojects.com MAIL TO: [email protected]