3877390
Distributed meetings: a meeting capture and broadcasting system
The common meeting is an integral part of everyday life for most workgroups. However, due to travel, time, or other constraints, people are often not able to attend all the meetings they need to. Teleconferencing and recording of meetings can address this problem. In this paper we describe a system that provides these features, as well as a user study evaluation of the system. The system uses a variety of capture devices (a novel 360° camera, a whiteboard camera, an overview camera, and a microphone array) to provide a rich experience for people who want to participate in a meeting from a distance. The system is also combined with speaker clustering, spatial indexing, and time compression to provide a rich experience for people who miss a meeting and want to watch it afterward.
28801152
Remote Collaboration on Physical Whiteboards
A whiteboard provides a large shared space for the participants to focus their attention and express their ideas, and is therefore a great collaboration tool for information workers. However, it has several limitations; notably, the contents on the whiteboard are hard to archive or share with people who are not present in the discussions. This paper presents our work in developing tools to facilitate collaboration on physical whiteboards by using a camera and a microphone. In particular, our system allows a user to take notes of a whiteboard meeting when he/she wants or in an automatic way, to transmit the whiteboard content to remote participants in real time and in an efficient way, and to archive the whole whiteboard session for efficient post-viewing. Our system can be retrofit to any existing whiteboard. With the help of a camera and a microphone, we are effectively bridging the physical and digital worlds.
2276524
Automatic Business Card Scanning with a Camera
In this paper, we present a system to automatically extract, rectify and enhance business card images. First the business card image patch is automatically segmented by minimizing a novel local-global variational energy. Second a quadrangle is fitted to the segmented image patch. With the four corner points of the quadrangle, we then estimate the physical aspect ratio of the business card and obtain a homography to rectify the quadrangle back to rectangular shape. We finally enhance the contrast of the rectified business card image using a S-shaped curve. Extensive experiments demonstrated the efficacy and robustness of our system.
18016173
Corner guided curve matching and its application to scene reconstruction
Corners and curves are important image features in many vision-based applications. Corners are usually more stable and easier to match than curves, while curves contain richer information of scene structure. In previously work, corners are often used to recover the epipolar geometry between two views, which is then used in curve matching to reduce the search space. However, information of the scene structure contained in this set of matched corners is ignored. In this paper we present a curve matching algorithm that is guided by a set of matched corners. Within a probabilistic framework, the role of the corner guidance is explicitly defined by a set of similarity-invariant unary measurements and by a similarity function. The similarity function provides stronger capability of resolving matching ambiguity than the epipolar constraint, and is integrated into a relaxation scheme to reduce computational complexity and improve accuracy of curve matching. Experimental results clearly demonstrate the benefit of integrating corner matches into the curve matching procedure.
36184486
Image-Based Surface Detail Transfer
We present a novel technique, called Image-Based Surface Detail Transfer, to transfer geometric details from one surface to another with simple 2D image operations. The basic observation is that, without knowing its 3D geometry, geometric details (local deformations) can be extracted from a single image of an object in a way independent of its surface reflectance, and furthermore, these geometric details can be transferred to modify the appearance of other objects directly in images. We show examples including surface detail transfer between real objects, as well as between real and synthesized objects.
8951856
Model-based head pose tracking with stereovision
We present a robust model-based stereo head tracking algorithm that operates in real time on a commodity PC. The use of an individualized three-dimensional head model, coupled with the epipolar constraint from the stereo image pair greatly improves the robustness of the tracking. Experimental results have shown that our method is able to track all the six degrees of freedom of the rigid part of head motions, over an extended period of time, in the presence of large angular and translational head motions, partial occlusions, and/or dramatic facial expression changes. Applications include human-computer interaction and eye-gaze correction for videoconferencing.
510739
An analysis of queueing systems with multi-task servers
Abstract We study a Markovian queueing system with multi-task servers. Each server can perform two types of job-serving the queue as primary jobs and taking vacations as secondary jobs. In such a system with c>1 servers, if at a service completion instant the server finds no customer waiting in line and the number of servers already on vacations is less than d(⩽c), he or she will take a vacation. At any time, the number of servers attending the queue or staying idle is at least c−d. By changing the parameter d, the queueing manager can better allocate the servers’ time to performing the primary jobs and the secondary jobs. Using the matrix analytic method, we provide a new computational algorithm for the stationary distributions of the queue length and waiting time. The conditional stochastic decomposition properties have been established for such a system.
45852164
An Agent-Based Hybrid Intelligent System for Financial Investment Planning
Many complex problems including financial investment planning require hybrid intelligent systems that integrate many intelligent techniques including expert systems, fuzzy logic, neural networks, and genetic algorithms. however, hybrid intelligent systems are difficult to develop due to complicated interactions and technique incompatibilities. this paper describes a hybrid intelligent system for financial investment planning that was built from agent points of view. this system currently consists of 13 different agents. the experimental results show that all agents in the system can work cooperatively to provide reasonable investment advice. the system is very flexible and robust. the success of the system indicates that agent technologies can significantly facilitate the construction of hybrid intelligent systems.
14844081
Constructing battery-aware virtual backbones in sensor networks
A critical issue in wireless sensor networks is to construct energy efficient virtual backbones for routing, broadcasting and data propagating. The minimum connected dominating set (MCDS) has been proposed as a backbone to reduce power dissipation and prolong network lifetime. However, we find that an MCDS cannot guarantee maximum network lifetime as it does not consider the battery discharging behavior. Recent study in battery technology reveals that the discharging of a battery is not linear. Batteries tend to discharge more power than needed, and reimburse the over-discharged power later if they have sufficiently long recovery time. In order to optimize network performance and construct an energy efficient virtual backbone in sensor networks, battery-awareness should be considered. In this paper we first study the mathematical battery discharging model and provide a simplified battery model suitable for implementation in sensor networks. We then introduce the concept of battery-aware connected dominating set (BACDS) and show that in general the BACDS can achieve longer lifetime than the MCDS. Then we show that finding a minimum BACDS (MBACDS) is NP-hard and give a distributed approximation algorithm to construct the BACDS. The resulting BACDS constructed by our algorithm is at most (8+/spl Delta/)opt size where /spl Delta/ is the maximum node degree and opt is the size of an optimal BACDS. The time and message complexities of the algorithm are O(n) and O(n(/spl radic/n+logn+/spl Delta/)), respectively, where n is the number of nodes in the network. The simulation results show that the BACDS constructed by our algorithm can save a significant amount of energy and achieve up to 30% longer network lifetime than the MCDS. To the best of our knowledge, this is the first work considering battery-awareness in the construction of connected dominating sets.
14282413
Distance-adaptive update protocols for scalable shared-memory multiprocessors
While update protocols generally induce lower miss rates than invalidate protocols, they tend to generate much traffic. This is one of the reasons why they are considered less cost-effectively scalable than invalidate protocols and, as a result, are avoided in most existing designs of scalable shared-memory multiprocessors. However, given the increasing relative cost of cache misses, update protocols are becoming more worthy of exploration. In this paper, we present a model of sharing that is key to investigating the performance of optimized update protocols: the update distance model. The model gives insight into the update patterns that optimized protocols need to handle. Using this model, we design a new family of protocols that we call distance-adaptive protocols. In these schemes, the directory records the update patterns observed and then uses them to selectively send updates and invalidations to processors. As a result, traffic and miss rates are kept low. We present an implementation of these protocols based on a dynamic pointer scheme. A performance comparison between one of these protocols and efficient invalidate and delayed competitive-update protocols over five applications shows that the new protocol decreases the execution time by an average of 15% and 10% respectively.
8796177
LIPS: Lightweight Internet Permit System for Stopping Unwanted Packets
In this paper, we propose a Lightweight Internet Permit System (LIPS) that provides a lightweight, scalable packet authentication mechanism for ensuring traffic-origin accountability. LIPS is a simple extension of IP, in which each packet carries an access permit issued by its destination host or gateway, and the destination verifies the access permit to determine if a packet is accepted or dropped. We will first present the design and the prototype implementation of LIPS on Linux 2.4 kernel. We then use analysis, simulations, and experiments to show how LIPS can effectively prevent protected critical servers and links from being flooded by unwanted packets with negligible overheads. We propose LIPS as an domain-to-domain approach to stop unwanted attacks, without requiring broad changes in backbone networks as other approaches. Therefore, LIPS is incrementally deployable in a large scale on common platforms with minor software patches.