5953229
Building an intelligent camera management system
Given rapid improvements in storage devices, network infrastructure and streaming-media technologies, a large number of corporations and universities are recording lectures and making them available online for anytime, anywhere access. However, producing high-quality lecture videos is still labor intensive and expensive. Fortunately, recent technology advances are making it feasible to build automated camera management systems to capture lectures. In this paper we report our design of such a system, including system configuration, audio-visual tracking techniques, software architecture, and user study. Motivated by different roles in a professional video production team, we have developed a multi-cinematographer single-director camera management system. The system performs lecturer tracking, audience tracking, and video editing all fully automatically, and offers quality close to that of human-operated systems.
10647458
Auto-summarization of audio-video presentations
As streaming audio-video technology becomes widespread, there is a dramatic increase in the amount of multimedia content available on the net. Users face a new challenge: How to examine large amounts of multimedia content quickly. One technique that can enable quick overview of multimedia is video summaries; that is, a shorter version assembled by picking important segments from the original.
We evaluate three techniques for automatic creation of summaries for online audio-video presentations. These techniques exploit information in the audio signal (e.g., pitch and pause information), knowledge of slide transition points in the presentation, and information about access patterns of previous users. We report a user study that compares automatically generated summaries that are 20%-25% the length of full presentations to author generated summaries. Users learn from the computer-generated summaries, although less than from authors' summaries. They initially find computer-generated summaries less coherent, but quickly grow accustomed to them.
5542322
Rendering with concentric mosaics
An image based system and process for rendering novel views of a real or synthesized 3D scene based on a series of concentric mosaics depicting the scene. In one embodiment, each concentric mosaic represents a collection of consecutive slit images of the surrounding 3D scene taken from a different viewpoint tangent to a circle on a plane within the scene. Novel views from viewpoints within circular regions of the aforementioned circle plane defined by the concentric mosaics are rendered using these concentric mosaics. Specifically, a slit image can be identified by a ray originating at its viewpoint on the circle plane and extending toward the longitudinal midline of the slit image. Each of the rays associated with the slit images needed to construct a novel view will either coincide with one of the rays associated with a previously captured slit image, or it will pass between two of the concentric circles on the circle plane. If it coincides, then the previously captured slit image associated with the coinciding ray can be used directly to construct part of the novel view. If the ray passes between two of the concentric circles of the plane, then the needed slit image is interpolated using the two previously captured slit images associated with the rays originating from the adjacent concentric circles that are parallel to the non-coinciding ray. If the objects in the 3D scene are close to the camera, depth correction is applied to reduce image distortion for pixels located above and below the circle plane. In another embodiment, a single camera is used to capture a sequence of images. Each image includes image data that has a ray direction associated therewith. To render an image at a novel viewpoint, multiple ray directions from the novel viewpoint are chosen. Image data is combined from the sequence of images by selecting image data that has a ray direction substantially aligning with the ray direction from the novel viewpoint.
17606652
Solving the Chan-Vese Model by a Multiphase Level Set Algorithm Based on the Topological Derivative
In this work, we specifically solve the Chan-Vese active contour model by multiphase level set methods. We first develop a fast algorithm based on calculating the variational energy of the Chan-Vese model without the length term. We check whether the energy decreases or not when we move a point to another segmented region. Then we draw a connection between this algorithm and the topological derivative, a concept emerged from the shape optimization field. Furthermore, to include the length term of the Chan-Vese model, we apply a preprocessing step on the image by using nonlinear diffusion. We show numerical experiments to demonstrate the efficiency and the robustness of our algorithm.
11874775
Microarchitecture Level Interconnect Modeling Considering Layout Optimization
— In this paper, we study microarchitecture-level interconnect modeling for power and performance. Considering structural interconnects, layer assignment, and concurrent repeater and Flip-Flop (FF) insertion, we develop cycle-accurate microarchitecture-level power and throughput simulation and obtain an accurate modeling of interconnects at the early design stage. Experiment show that the simulation reduces over-estimation by up to 2.24X compared to the conventional power estimation based on purely stochastic interconnects and fixed switching factor. Furthermore, we optimize throughput with consideration of FF insertion for interconnects and floorplanning optimization. We show that throughput is not always higher for an increased clock frequency, and there exists an optimal clock frequency to maximize throughput for a given microarchitecture and given floorplan. In addition, floorplan optimized for IPC (instructions per cycle)-critical interconnects has little on the total interconnect length but improves throughput by 23.49%. As FF insertion becomes necessary to achieve the clock frequency specified by ITRS, we conclude that the traditional design flow optimizing IPC and clock frequency separately is no longer valid, and coupled microarchitecture and layout optimization may improve both power efficiency and throughput.
14206406
Performance-Aware Workflow Management for Grid Computing
Grid middleware development has advanced rapidly over the past few years to support component-based programming models and service-oriented architectures. This is most evident with the forthcoming release of the Globus toolkit (GT4), which represents a convergence of concepts (and standards) from both the grid and web-services communities. Grid applications are increasingly modular, composed of workflow descriptions that feature both resource and application dynamism. Understanding the performance implications of scheduling grid workflows is critical in providing effective resource management and reliable service quality to users. This paper describes a series of extensions to an existing performance-aware grid management system (TITAN). These extensions provide additional support for workflow prediction and scheduling using a multi-domain performance management infrastructure.
1023314
An Investigation into the Application of Different Performance Prediction Methods to Distributed Enterprise Applications
Response time predictions for workload on new server architectures can enhance Service Level Agreement–based resource management. This paper evaluates two performance prediction methods using a distributed enterprise application benchmark. The historical method makes predictions by extrapolating from previously gathered performance data, while the layered queuing method makes predictions by solving layered queuing networks. The methods are evaluated in terms of: the systems that can be modelled; the metrics that can be predicted; the ease with which the models can be created and the level of expertise required; the overheads of recalibrating a model; and the delay when evaluating a prediction. The paper also investigates how a prediction-enhanced resource management algorithm can be tuned so as to compensate for predictive inaccuracy and balance the costs of SLA violations and server usage.
6609824
Performance-Aware Load Balancing for Multiclusters
In a multicluster architecture, where jobs can be submitted through each constituent cluster, the job arrival rates in individual clusters may be uneven and the load therefore needs to be balanced among clusters. In this paper we investigate load balancing for two types of jobs, namely non-QoS and QoS-demanding jobs and as a result, two performance-specific load balancing strategies (called ORT and OMR) are developed. The ORT strategy is used to obtain the optimised mean response time for non-QoS jobs and the OMR strategy is used to achieve the optimised mean miss rate for QoS-demanding jobs. The ORT and OMR strategies are mathematically modelled combining queuing network theory to establish sets of optimisation equations. Numerical solutions are developed to solve these optimisation equations, and a so called fair workload level is determined for each cluster. When the current workload in a cluster reaches this pre-calculated fair workload level, the jobs subsequently submitted to the cluster are transferred to other clusters for execution. The effectiveness of both strategies is demonstrated through theoretical analysis and experimental verification. The results show that the proposed load balancing mechanisms bring about considerable performance gains for both job types, while the job transfer frequency among clusters is considerably reduced. This has a number of advantages, in particular in the case where scheduling jobs to remote resources involves the transfer of large executable and data files.