In synchronous circuit designs, clock skew is difficult to minimize because a single physical layout of a clock tree must satisfy multiple constraints in a complicated power mode environment where certain modules may operate with different voltages. In this paper, we use adjustable delay buffers (ADB) whose delays can be tuned or adjusted to minimize clock skew under different power modes. Assuming that the positions of$k$ADBs are already determined, we first propose a linear-time optimal algorithm which assigns the values of ADBs so that the skew is optimal among all possible ADB assignments with a possibility of latency penalty. Then, we propose a modified optimal algorithm without latency penalty. We also propose an efficient heuristic to determine good positions for ADBs. Our results show significant improvement when compared to cases without ADBs.

In synchronous circuit designs, clock skew is difficult to minimize because a single physical layout of a clock tree must satisfy multiple constraints in a complicated power mode environment where certain modules may operate with different voltages. In this paper, we use Adjustable Delay Buffers (ADB) whose delays can be tuned or adjusted to minimize clock skew under different power modes. Assuming that the positions of k ADBs are already determined, we propose a linear-time optimal algorithm which assigns the values of ADBs so that the skew is optimal among all possible ADB assignments. We also propose an efficient heuristic to determine good positions for ADBs. Our results show significant improvement when compared to cases without ADBs. Categories and Subject Descriptors B.6.3 [Logic Design]: Design Aids — Optimization General Terms: Algorithms, Reliability

In this paper, a novel method is presented to detect video copies for a given video query. These copies and the query have identical or near-duplicate content, which might differ in their spatiotemporal structures slightly. To address both the efficient and effective issues, we conduct the bag-of words model for video feature representation, and apply a coarse-to-fine matching scheme to analyze the video spatiotemporal structure. The proposed method can deal with various kinds of video transformations, such as cropping, zooming, speed change, and subsequence insertion/deletion, which are not well addressed in existing methods. Besides, two indexing methods are employed to speed up the matching process. Experimental results show that the proposed method can behave in an efficient and effective manner.

This work is motivated by a strong market demand in the replacement of NOR flash memory with NAND flash memory to cut down the cost in many embedded-system designs, such as mobile phones. Different from LRU-related caching or buffering studies, we are interested in prediction-based prefetching based on given execution traces of application executions. An implementation strategy is proposed in the storage of the prefetching information with limited SRAM and run-time overheads. An efficient prediction procedure is presented based on information extracted from application executions to reduce the performance gap between NAND flash memory and NOR flash memory in reads. With the behavior of a target application extracted from a set of collected traces, we show that data access to NOR flash memory can be responded effectively over the proposed implementation.

This paper presents a visualization tool, VisHD, that can visualize the spatial distribution of vector points in high dimensional feature space. It is important to handle high dimensional information in many areas of computer science. VisHD provides several methods for dimension reduction in order to map the data from high dimensional space to low dimensional one. Next, this system builds intuitive visualization for observing the characteristics of the data set, whether these data are pre-defined labels or not. In addition, some useful functions have been implemented to facilitate the information visualization. This paper, finally, gives some experiments and discussions for showing the abilities of VisHD for visualizing high-dimensional data.