14291535
Background Updating for Visual Surveillance
Scene changes such as moved objects, parked vehicles, or opened/closed doors need to be carefully handled so that interesting foreground targets can be detected along with the short-term background layers created by those changes. A simple layered modeling technique is embedded into a codebook-based background subtraction algorithm to update a background model. In addition, important issues related to background updating for visual surveillance are discussed. Experimental results on surveillance examples, such as unloaded packages and unattended objects, are presented by showing those objects as short-term background layers.
6524269
Real-time foreground-background segmentation using codebook model
We present a real-time algorithm for foreground-background segmentation. Sample background values at each pixel are quantized into codebooks which represent a compressed form of background model for a long image sequence. This allows us to capture structural background variation due to periodic-like motion over a long period of time under limited memory. The codebook representation is efficient in memory and speed compared with other background modeling techniques. Our method can handle scenes containing moving backgrounds or illumination variations, and it achieves robust detection for different types of videos. We compared our method with other multimode modeling techniques. In addition to the basic algorithm, two features improving the algorithm are presented-layered modeling/detection and adaptive codebook updating. For performance evaluation, we have applied perturbation detection rate analysis to four background subtraction algorithms and two videos of different types of scenes.
838252
Background modeling and subtraction by codebook construction
We present a new fast algorithm for background modeling and subtraction. Sample background values at each pixel are quantized into codebooks which represent a compressed form of background model for a long image sequence. This allows us to capture structural background variation due to periodic-like motion over a long period of time under limited memory. Our method can handle scenes containing moving backgrounds or illumination variations (shadows and highlights), and it achieves robust detection for compressed videos. We compared our method with other multimode modeling techniques.
1602753
Interactive mosaic generation for video navigation
Navigation through large multimedia collections that include videos and images still remains cumbersome. In this paper, we introduce a novel method to visualize and navigate through the collection by creating a mosaic image that visually represents the compilation. This image is generated by a labeling-based layout algorithm using various sizes of sample tile images from the collection. Each tile represents both the photographs and video files representing scenes selected by matching algorithms. This generated mosaic image provides a new way for thematic video and visually summarizes the videos. Users can generate these mosaics with some predefined themes and layouts, or base it on the results of their queries. Our approach supports automatic generation of these layouts by using meta-information such as color, time-line and existence of faces or manually generated annotated information from existing systems (e.g., the Family Video Archive).
17794843
TCP throughput analysis under transmission error and congestion losses
This paper analyzes the performance of a large population of long lived TCP flows experiencing random packet losses due to both random transmission errors and congestion created by the sharing of a common tail drop bottleneck router. We propose a natural and simple model for the joint throughput evolution of the set of TCP sessions under such a mix of losses. For the case of Poisson transmission errors, we show that the asymptotic model where the population tends to infinity leads to a well defined and tractable dynamical system. In particular, we get the mean value of the throughput of each session as a function of the transmission error rate and the synchronization rate in the bottleneck router. The large population asymptotic model has two interesting and non-intuitive properties: 1) there exists a positive threshold (given in closed form) on the transmission error rate above which there are no congestion losses at all in steady state; 2) below this threshold, the mean throughput of each flow is an increasing function of the transmission error rate, so that the maximum mean value is in fact achieved when the transmission error rate is equal to this threshold. The finite population model and models based on other classes of point processes are also studied. In particular, a sufficient condition is obtained for the existence of congestion times in the case of arbitrary transmission error point processes.
8709932
Mapping Cooperating GRID Applications by Affinity for Resource Characteristics
The Computational Grid, distributed and heterogeneous collections of computers in the Internet, has been considered a promising platform for the deployment of various high-performance computing applications. One of the crucial issues in the Grid is how to discover, select and map possible Grid resources in the Internet for meeting given applications. The general problem of statically mapping tasks to nodes has been shown to be NP-complete. In this paper, we propose a mapping algorithm for cooperating Grid applications by the affinity for the resources, named as MACA. The proposed algorithm utilizes the general affinity of Grid applications for certain resource characteristics such as CPU speeds, network bandwidth, and input/output handling capability. To show the effectiveness of the proposed mapping algorithm, we compare the performance of the algorithm with some previous mapping algorithms by simulation. The simulation results show that the algorithm could effectively utilize the affinity of Grid applications and shows good performance.
26299662
A Resilient Multipath Routing Protocol for Wireless Sensor Networks
Wireless sensor networks should be self-configuring, highly scalable, redundant, and robust in dealing with shifting topologies due to node failure and environment changes. The energy of a sensor node is the most important system resource, and one of the best ways of conserving energy is to distribute the routing load across all sensor nodes as much equally as possible. Considering the load balance for conserving energy, multipath routing protocols have been employed in sensor networks. In this paper we present a resilient multipath routing protocol based on AODV, named as RMRP, for wireless sensor networks. RMRP is an AODV-based multipath routing protocol in which sensor nodes setup double routing paths toward sink nodes in an AODV fashion and select one of them randomly for forwarding a packet. RMRP proposes a resilient route maintenance scheme which repairs broken links by utilizing localized information around neighbor nodes of the broken link, thereby reducing the flooding range of control messages. To show the effectiveness of the proposed route maintenance scheme, we evaluate the performance enhancement of the proposed scheme by ns2-based simulation.
39411693
IP lookup by binary search on prefix length
Waldvogel et al. [ACM SIGCOMM, 1997, 25-36] have proposed a collection of hash tables (CHT) organization for an IP router table. IP lookup can be done with O(log l/sub dist/) hash-table searches, where l/sub dist/ is the number of distinct prefix-lengths (also equal to the number of hash tables in the CHT). Srinivasan and Varghese [ACM transactions on Computer Systems, Feb:1-40, 1999] have proposed the use of controlled prefix-expansion to reduce the value of l/sub dist/. The algorithm of [V. Srinivasan, 1999] does not minimize the storage required by the prefixes and markers for the resulting set of prefixes. We develop an algorithm that minimizes storage requirement but takes O(nW/sup 3/ + kW/sup 4/) time, where k is the desired number of distinct lengths, n is the number of prefixes, and W is the length of the longest prefix. Also, we propose improvements to the heuristic of [V. Srinivasan, 1999].