271858
Providing scalable on-demand video services for heterogeneous receivers
To provide scalable video-on-demand services, precious system bandwidth must be shared among video requests. Although many efficient bandwidth-sharing techniques have been proposed, they are all designed for homogeneous receivers, i.e., the clients are assumed to have the same receiving bandwidth. For networks with client heterogeneity, these techniques either cannot work or have to compromise their performance. In this paper, we address this problem and propose an efficient solution allowing each client to use its whole receiving bandwidth to download data. To serve a client, the server first selects a set of serving channels for the client according to its actual receiving bandwidth. The video data needed for this client are then scheduled and dynamically adjusted for delivery over these channels. We evaluate the performance of the new technique using simulation and compare it with an existing scheme. Our study shows that by effectively leveraging client heterogeneity, the new technique achieves significantly smaller service latency
2308501
A framework for parsing colonoscopy videos for semantic units
Colonoscopy is an important screening procedure for colorectal cancer. During this procedure, the endoscopist visually inspects the colon. Currently, there is no content-based analysis and retrieval system that automatically analyzes videos captured from colonoscopic procedures and provides a user-friendly and efficient access to important content. Such a system will be valuable for endoscopic research and education. The first necessary step for the analysis is parsing for semantic units. Since the characteristics of colonoscopy videos differ from those of videos studied in the literature, we introduce a new video parsing framework that includes: (i) a new scene definition and a new video parsing paradigm; (ii) a novel scene segmentation algorithm using audio analysis and finite state automata to recognize scenes and associated boundaries. Our experimental results show average precision and recall of 95% and 81%, respectively, for parsing scenes. The framework is extensible to videos captured from other endoscopic procedures such as upper gastrointestinal endoscopy, enteroscopy, cystoscopy, and laparoscopy.
14407932
Automatic measurement of quality metrics for colonoscopy videos
Colonoscopy is the accepted screening method for detection of colorectal cancer or its precursor lesions, colorectal polyps. Indeed, colonoscopy has contributed to a decline in the number of colorectal cancer related deaths. However, not all cancers or large polyps are detected at the time of colonoscopy, and methods to investigate why this occurs are needed. We present a new computer-based method that allows automated measurement of a number of metrics that likely reflect the quality of the colonoscopic procedure. The method is based on analysis of a digitized video file created during colonoscopy, and produces information regarding insertion time, withdrawal time, images at the time of maximal intubation, the time and ratio of clear versus blurred or non-informative images, and a first estimate of effort performed by the endoscopist. As these metrics can be obtained automatically, our method allows future quality control in the day-to-day medical practice setting on a large scale. In addition, our method can be adapted to other healthcare procedures. Last but not least, our method may be useful to assess progress during colonoscopy training, or as part of endoscopic skills assessment evaluations.
14348286
A Visual Model Approach for Parsing Colonoscopy Videos
Colonoscopy is an important screening procedure for colorectal cancer. During this procedure, the endoscopist visually inspects the colon. Currently, there is no content-based analysis and retrieval system that automatically analyzes videos captured from colonoscopic procedures and provides a user-friendly and efficient access to important content. Such a system will be valuable as an educational resource for endoscopic research, a platform to assess procedural skills for endoscopists, and a platform for mining for unknown abnormality patterns that may lead to colorectal cancer. The first necessary step for the analysis is parsing for semantic units. In this paper, we propose a new visual model approach that employs visual features extracted directly from compressed videos together with audio analysis to discover important semantic units called scenes. Our experimental results show average precision and recall of 93% and 85%, respectively.
17046491
Lightweight agents for intrusion detection
We have designed and implemented an intrusion detection system (IDS) prototype based on mobile agents. Our agents travel between monitored systems in a network of distributed systems, obtain information from data cleaning agents, classify and correlate information, and report the information to a user interface and database via mediators.Agent systems with lightweight agent support allow runtime addition of new capabilities to agents. We describe the design of our Multi-agent IDS and show how lightweight agent capabilities allowed us to add communication and collaboration capabilities to the mobile agents in our IDS.
14591533
Leveraging broadband access for true on-demand delivery of Internet videos
We consider in this paper how the increasingly popular broadband access can be leveraged for scalable and cost-effective video service. Although much work has been done for such service, the existing techniques either are not designed for on-demand video delivery, or do not take into account the vastly improved client receiving capability. In this paper, we address this problem and develop three novel video delivery techniques with two ultimate goals: minimizing service latency and maximize data sharing. With the new techniques, a client can be served as soon as server resource becomes available and meanwhile, all its receiving bandwidth can be used for data receiving. In particular, in the proposed dynamic scheduling algorithm, the efficiency of data sharing is further improved by also exploring server bandwidth for early delivery of video segments. This innovation is contradicted to the intuition that each video segment should be delivered as late as possible in order to maximize data sharing. We evaluate the performance of our new techniques using simulation and our study convincingly shows that with the new schemes, zero service latency can indeed be achieved with very minimal system resource.
11369157
Statistical model of lossy links in wireless sensor networks
Recently, several wireless sensor network studies demonstrated large discrepancies between experimentally observed communication properties and properties produced by widely used simulation models. Our first goal is to provide sound foundations for conclusions drawn from these studies by extracting relationships between location (e.g. distance) and communication properties (e.g. reception rate) using non-parametric statistical techniques. The objective is to provide a probability density function that completely characterizes the relationship. Furthermore, we study individual link properties and their correlation with respect to common transmitters, receivers and geometrical location. The second objective is to develop a series of wireless network models that produce networks of arbitrary sizes with realistic properties. We use an iterative improvement-based optimization procedure to generate network instances that are statistically similar to empirically observed networks. We evaluate the accuracy of our conclusions using our models on a set of standard communication tasks, like connectivity maintenance and routing.
3837698
On Staleness and the Delivery of Web Pages
A popular technique to improve the scalability of a web based system is caching at proxy servers. Caching has the drawback that a cached page becomes stale when the page is updated at the web server. In some cases, staleness may not be completely avoided because the server may not wish to expend the processing and communication resources required to transmit all the updates immediately. In general, if updates are transmitted less frequently, the staleness will tend to increase, but the amount of resources consumed will be reduced. The tradeoff between resource consumption and staleness is investigated. A measure of staleness is defined and optimization problems are formulated. The solutions to these problems allow one to come up with an optimal strategy for transmitting page updates. Numerical examples showing the resource consumption/staleness tradeoff are presented.
1973000
Gateway placement for latency and energy efficient data aggregation [wireless sensor networks]
We propose the use of multiple gateways to significantly reduce latency and energy consumption in multi-hop wireless sensor networks during data aggregation. We have derived efficient integer linear programming formulations as well as a novel negative selection statistically-tuned heuristics. The heuristics are based on newly developed relaxation based lower bounds that are also used to quantify the effectiveness of the proposed heuristics. Our simulation study indicates that the use of gateways can often reduce latency and energy consumption by several times.
6612620
Design techniques for sensor appliances: foundations and light compass case study
We propose the first systematic, sensor-centric approach for quantitative design of sensor network appliances. We demonstrate its use by designing light appliance devices and the associated middleware. We have developed five models which are required to make this problem tractable and to undertake the challenging task of designing light sensor appliances: i. physical world, ii. light sensor, iii. physical phenomenon, iv. appliance design, and v. computational model. With these models in place, we present the new design methodology that consists of two main steps: 1. a procedure for placement of individual sensors of the appliances, and 2. error minimization-based sensor data interpretation middleware. We have developed new optimization techniques for both tasks. A portable light sensor system was designed using the optimization intensive procedure, and its effectiveness demonstrated.
6228197
Copy detection for intellectual property protection of VLSI designs
We give the first study of copy detection techniques for VLSI CAD applications; these techniques are complementary to previous watermarking-based IP protection methods in finding and proving improper use of design IP. After reviewing related literature (notably in the text processing domain), we propose a generic methodology for copy detection based on determining basic elements within structural representations of solutions (IPs), calculating (context-independent) signatures for such elements, and performing fast comparisons to identify potential violators of IP rights. We give example implementations of this methodology in the domains of scheduling, graph coloring and gate-level layout; experimental results show the effectiveness of our copy detection schemes as well as the low overhead of implementation. We remark on open research areas, notably the potentially deep and complementary interaction between watermarking and copy detection.