27936359
A new content-based hybrid video transcoding method
Many video transcoding architectures have been proposed to reduce the bitrates of compressed video bitstreams. Requantization of transformed coefficients (such as DCT coefficients), spatial resolution down-sampling, and temporal resolution down-sampling are the three transcoding tools which are commonly used to reduce compressed video bitrates. We propose a new video transcoding method that combines the use of different transcoding tools to transcode compressed video bit streams to various target bitrates while maintaining good subjective/objective video quality. The transcoding tools are selected based on the video content, which is characterized by two video content descriptors inferring the video spatial and motion activities, respectively. These two content descriptors can be readily computed from the compressed video bit streams without full decompression. Experimental results show that the proposed method can provide better video quality than other existing transcoders that make use of a single transcoding tool.
22284885
Motion vector re-estimation for fractional-scale video transcoding
In video transcoding, the compressed video is often converted to a lower resolution in order to reduce the bit rate. One way to achieve this is to first decompress the compressed video, down-sample each frame, and then re-compress the down-scaled frame sequences. This method can obtain high-quality compressed video bit-streams; however, it involves motion vector estimation that is computationally complex. Recently, some transcoding techniques have been proposed to compute the motion vectors for a compressed video with lower resolution using the motion vectors directly from the original compressed video. These techniques, however, cannot be used in arbitrary-size video down-scaling, e.g for converting CIF (Common Intermediate Format) video to sub-QCIF (Quarter CIF) video or QCIF to sub-QCIF. In this paper, we propose a video transcoding method that can estimate the motion vectors for arbitrary-size down-scaled video. It can provide video quality that is comparable to full-search motion estimation but with very low computational complexity.
147466
A vision-based approach to early detection of drowning incidents in swimming pools
We present in this paper a vision-based approach to detection of drowning incidents in swimming pools at the earliest possible stage. The proposed approach consists of two main parts: a vision component which can reliably detect and track swimmers in spite of large scene variations of monitored pool areas, and an event-inference module which parses observation sequences of swimmer features for possible drowning behavioral signs. The vision component employs a model-based approach to represent and differentiate the background pool areas and foreground swimmers. The event-inference module is constructed based on a finite state machine, which integrates several reasoning rules formulated from universal motion characteristics of drowning swimmers. Possible drowning incidents are quickly detected using a sequential change detection algorithm. We have applied the proposed approach to a number of video clips of simulated drowning and obtained promising results as reported in this paper.
32434128
Fast motion vector and bitrate re-estimation for arbitrary downsizing video transcoding
In video transcoding technique, many fast methods have been proposed to estimate the motion vectors required for downsizing a pre-coded video by an integer factor. In this paper we examine and compare several fast video transcoding methods for downsizing a pre-coded video by an arbitrary factor. Methods which out-perform others are identified and discussed. We also propose a new method to model the relation between bitrate and frame size under low bitrate condition. With this new model, we can re-estimate the bitrate according to a required frame size or select a suitable frame size for a given target bitrate, while maintaining good video quality. Experimental results are presented to show the performance of the proposed fast motion vector and bitrate re-estimation methods.
34798576
Video transcoding for fast forward/reverse video playback
Fast forward and fast reverse playbacks are two common video browsing functions provided in many analog and digital video players. They help users quickly find and access video segments of interest by scanning through the content of a video at a faster than normal playback speed. We propose a video transcoding approach to realizing fast forward and reverse video playbacks by generating a new compressed video from a pre-coded video. To reduce the computational requirements, we design and compare several fast algorithms for estimating the motion vectors required in transcoded video. To accommodate changes due to frame skipping for fast video playback, we also alter the group-of-pictures structure of transcoded video. In addition, subjective tests are conducted to assess the minimum video peak-signal-to-noise-ratio degradation that is perceptible to viewers at different fast playback speeds. To this end, we obtain an adaptive video transcoding method, which combines intra-coding and inter-coding with a fast motion vector reestimation method to strike a good balance between computational complexity and transcoded video quality. Experimental results are reported to show the efficacy of the proposed method.
9891360
Image retrieval with SVM active learning embedding Euclidean search
Image retrieval with relevance feedback suffers from the small sample problem. Recently, SVM active learning has been proposed to tackle this problem, showing promising results. However, a small but sufficient number of initially labelled samples are still required to ensure subsequent efficient active learning and good retrieval performance. In the existing method, the user is asked to label more images before active learning starts. In this paper, a method of embedding Euclidean search into SVM active learning is proposed. With the help of Euclidean search, the adverse effect on retrieval performance due to lack of initially labelled samples can be reduced. Experimental results demonstrate the improvement by the proposed method, especially when the number of initially labelled samples is small.
27173472
Guest editorial
increasing relevance of security, safety and privacy issues 2 and of d the their perceived or subjective counterpartÈin IT and in particular on the web ; fact that trust is essential for any organization, or any human social d the relation, and thus should be maintained and created in new forms of computer supported collaboration and computer mediated communities ; fact that what is growing on the web is a new market, Electronic d the Commerce (EC), and since a market is mainly based on selÐsh interests, it is open to cheating and to competition between attractive alternatives. Hence, this new virtual market strongly requires trust in the chosen partner, trust in rules and procedures, trust in guaranties and enforcing authorities.
14496219
Optimal Processing Policies for an e-Commerce Web Server
The explosive growth in online shopping has provided online retailers impressive opportunities to extend revenue and profit. However, retailers may lose considerable online business from slow response times at electronic shopping sites. Although increasing server capacity may improve response time, the resources needed to do so are clearly not free. In this study, we propose a scheme that can improve a server's performance with no more than its current capacity. This scheme is based on priority processing, where the priority assigned to a customer depends on the potential revenue that is likely to be generated from the customer. The results for single-period analysis show that the benefit from priority processing increases as the server becomes more heavily utilized. 
 
We have also modeled a multiperiod version of the problem, where the demand in a period depends on the quality of service (QoS) that buyers receive in the previous period. In the multiperiod problem, both the server capacity and the processing policy in each period are determined optimally. Here, it may be optimal for the retailer to sacrifice profit and increase QoS in initial periods in order to increase demand (and revenue) in later periods. Thus, the processing policy of the server evolves from an emphasis on QoS in initial periods, to one on profit in subsequent periods.
31919378
A risk management of ASPs
Application service providers (ASPs) provide access to application software over wide area networks and have been viewed as a means of making the benefits of outsourcing available to small businesses. However, many enterprise ASPs get the majority of their revenue from very large businesses while many vertical niche ASPs get their revenue from small businesses. We analyze this seeming anomaly from a risk management perspective. ASPs present a greater risk management problem to would-be customers than traditional outsourcing. We analyze the nature of the risk differences and then propose a model of how would-be customers process those risks. In our model, prospects first assess whether they can tolerate the worst case scenario and if they are able to do due diligence on the likely outcome. They consider benefits only if one of the previous assertions is true. The worst case scenario for enterprise applications is truly dire and only technologically sophisticated businesses are better able to identify the true risk profile. For vertical niche ASPs the worst case scenario is relatively mild, but economies of scale make the benefits relatively more appealing to small businesses.
181942
Search engine driven author disambiguation
In scholarly digital libraries, author disambiguation is an important task that attributes a scholarly work with specific authors. This is critical when individuals share the same name. We present an approach to this task that analyzes the results of automatically-crafted Web searches. A key observation is that pages from rare Web sites are stronger source of evidence than pages from common Web sites, which we model as inverse host frequency (IHF). Our system is able to achieve an average accuracy of 0.836
16080551
Institutional trust and familiarity in online interorganizational relationships
Institutional trust is necessary for inter-organizational relationships in e-commerce. Two types of institutional trust are herein proposed (a) third-party institution-based trust, which deals with intermediary-driven structures, and (b) bilateral institutionalized trust, which deals with dyadic inter-organizational processes. We examine how these two types of institutional trust develop through their underlying dimensions (i) structural assurances, (ii) facilitating conditions, and (iii) situational normality. We focus on how interorganizational trust and online relationship building can be longitudinally facilitated by institutional trust, which can initially substitute and progressively complement the role of familiarity. More specifically, this study focuses on the time-dependent nature of initial trust formation, and specifically on the role of relationship phase (from exploration to maturity), by describing (a) the role of bilateral relative to third-party institutional trust on interorganizational trust, and (b) the transition of the underlying dimensions of institutional trust. This research has implications for (1) the longitudinal nature and role of institutional trust in online relationship building, (2) the literature on initial trust formation, and (3) the strategic design and use of cost-effective trust-building mechanisms.