19776539
Stack value file: custom microarchitecture for the stack
As processor performance increases, there is a corresponding increase in the demands on the memory system, including caches. Research papers have proposed partitioning the cache into instruction/data, temporal/non-temporal, and/or stack/non-stack regions. Each of these designs can improve performance by constructing two separate structures which can be probed in parallel while reducing contention. In this paper, we propose a new memory organization that partitions data references into stack and nonstack regions. Non-stack references are routed to a conventional cache. Stack references, on the other hand, are shown to have several characteristics that can be leveraged to improve performance using a less conventional storage organization. This paper enumerates those characteristics and proposes a new microarchitectural feature, the stack value file (SVF), which exploits them to improve instruction-level parallelism, reduce stack access latencies, reduce demand on the first-level cache, and reduce data bus traffic. Our results show that the SVF can improve execution performance by 29 to 65% while reducing overhead traffic for the stack region by many orders of magnitude over cache structures of the same size.
19026342
Eager writeback - a technique for improving bandwidth utilization
Modern high-performance processors utilize multi-level cache structures to help tolerate the increasing latency of main memory. Most of these caches employ either a writeback or a write-through strategy to deal with store operations. Write-through caches propagate data to more distant memory levels at the time each store occurs, which requires a very large bandwidth between the memory hierarchy levels. Writeback caches can significantly reduce the bandwidth requirements between caches and memory by marking cache lines as dirty when stores are processed and writing those lines to the memory system only when that dirty line is evicted. Unfortunately, for applications that experience significant numbers of cache misses due to streaming data, writeback cache designs can degrade overall system performance by clustering bus activity when dirty lines contend with data being fetched into the cache. In this paper we present a new technique called Eager Writeback, which re-distributes and balances memory traffic by writing and "cleaning" dirty cache lines prior to their eviction. Eager Writeback can be viewed as a compromise between write-through and writeback policies, in which dirty lines are written later than write-through, but prior to writeback. We will show that this approach can reduce the large number of writes seen in a write-through design, while avoiding the performance degradation caused by clustering bus traffic in a writeback approach.
26133819
Multi-agent Technology as an enabler of Computer Supported Cooperative Work for the Mobile Workforce
This paper proposes an agent-based computer supported cooperative work system known as TeamWorker that enables cooperation between mobile workers for the execution of their jobs by providing services via conversational components (C-COMs). C-COMs, encapsulate agent interaction protocols, which can be dynamically plugged into participating agents. Furthermore, the intelligence and autonomy of agent technology is applied to overcome the barriers faced in mobile computing environments, such as difficulty in monitoring work progress, device diversity, need for multi-modal human agent interface, etc. Finally, we discuss how TeamWorker has been applied to a real mobile business process in a telecommunications company in the UK.
19085830
An analysis of multiple-class vacation queues with individual thresholds
This study examines a multiple-class M/G/1 queue with multiple thresholds. Each class of customer arrives according to an independent Poisson process, and each class has its own threshold. The idle server is reactivated as soon as any one of the thresholds is reached. Both FCFS and non-preemptive priority cases are considered. The Laplace-Stieltjes transform of the waiting time distribution function and the mean waiting time for each class of customers are derived.
7999511
A proportional-share scheduler for multimedia applications
This paper presents a proportional-share CPU scheduler which can support multimedia applications in a general-purpose workstation environment. For this purpose, we have extended the stride scheduler which is designed originally for conventional tasks. New scheduling parameters are introduced to specify timing requirements of multimedia applications. Through the, use of the rate regulator, the accuracy error of the scheduling is reduced to O(1). Separate task groups are proposed to represent both relative shares and absolute shares. The proposed scheduler is evaluated using a simulation study. The results show that the proposed scheduler achieves improved accuracy and adaptability as well as fairness.
7138459
Comparison of Feature Extraction Techniques for Watermark Synchronization
This paper evaluates feature extraction techniques in aspect of watermark synchronization. Most watermarking algorithms suffer from geometric distortion attacks that desynchronize the location of the inserted watermark. The process of synchronizing the location for watermark insertion and detection is crucial to design robust watermarking. One solution for watermark synchronization is to use features. This paper reviews feature extraction techniques in feature-based watermarking: the Harris corner detector and the Mexican Hat wavelet scale interaction method. We evaluate the scale-invariant keypoint extractor in comparison with others. After feature extraction, the set of triangles is generated by Delaunay tessellation. These triangles are the location for watermarking. Redetection ratio of triangles is measured against geometric distortion attacks and signal processing attacks. Experimental results show that the scale–invariant keypoint extractor is appropriate for robust watermarking.
12136049
Content-Based Synchronization Using the Local Invariant Feature for Robust Watermarking
This paper addresses the problem of content-based synchronization for robust watermarking. Synchronization is a process of extracting the location to embed and detect the signature, copyright information, so that it is crucial for the robustness of the watermarking system. In this paper, we will review representative content-based approaches and propose a new synchronization method based on the scale invariant feature transform. In content-based synchronization approaches, it is important to extract robust features even with image distortions and we suspect that the consideration of local image characteristics will be helpful. The scale invariant feature transform regards these characteristics and is invariant to noise, spatial filtering, geometric distortions, and illumination changes of the image. Through experiments, we will compare the proposed method with representative content-based approaches and show the appropriateness for robust watermarking.