3185763
Address generation for nanowire decoders
Nanoscale crossbars built from nanowires can form high density memories and programmable logic devices. To integrate such nanoscale devices with CMOS circuits, nanowire decoders were invented. Due to the stochastic nature of the nanoscale fabrication, the decoder addresses that address the nanowires selectively must be generated after fabrication. In this paper, we develop a mathematical model of the nanowire decoders for the generation of the proper addresses. Assuming a simple testing approach calledon-off measurement, we prove that the maximum number of the proper addresses can be generated in finite time. We design the algorithms to generate the required number of the proper addresses. Experimental results confirm the efficiency of our algorithms.
2271365
Minimal period retiming under process variations
With aggressive scaling down of feature sizes in VLSI fabrication, process variations have become a critical issue in designs. With process variations, timing optimization should consider the randomness introduced in delays. This paper considers how to retime a circuit under process variations. A statistical retiming problem is defined on the concept of a disutility function. Based on a new minimal period retiming algorithm, two algorithms are presented for the statistical retiming problem. Both theoretical and experimental results are given.
6804856
Processing rate optimization by sequential system floorplanning
The performance of a sequential system is usually measured by its frequency. However, with the appearance of global interconnects that require multiple clock periods to communicate the throughput is usually traded-off for higher frequency (for example, through wire pipelining or latency insensitive design). Therefore, we propose to use the processing rate, defined as the amount of processed inputs per unit time, as the performance measure. We show that the minimal ratio of the flip-flop number over the delay on any cycle is an upper bound of the processing rate. Since the processing rate of a sequential system is mainly decided by its floorplan when interconnect delays are dominant, the problem of floorplanning for processing rate optimization is formulated and solved. We optimize the processing rate bound directly in a floorplanner by applying Howard's algorithm incrementally. Experimental results confirm the effectiveness of our approach
7128221
TAPHS: thermal-aware unified physical-level and high-level synthesis
Thermal effects are becoming increasingly important during integrated circuit design. Thermal characteristics influence reliability, power consumption, cooling costs, and performance. It is necessary to consider thermal effects during all levels of the design process, from the architectural level to the physical level. However, design-time temperature prediction requires access to block placement, wire models, power profile, and a chip-package thermal model. Thermal-aware design and synthesis necessarily couple architectural-level design decisions (e.g., scheduling) with physical design (e.g., floorplanning) and modeling (e.g., wire and thermal modeling). This article proposes an efficient and accurate thermal-aware floor-planning high-level synthesis system that makes use of integrated high-level and physical-level thermal optimization techniques. Voltage islands are automatically generated via novel slack distribution and voltage partitioning algorithms in order to reduce the design's power consumption and peak temperature. A new thermal-aware floorplanning technique is proposed to balance chip thermal profile, thereby further reducing peak temperature. The proposed system was used to synthesize a number of benchmarks, yielding numerous designs that trade off peak temperature, integrated circuit area, and power consumption. The proposed techniques reduces peak temperature by 12.5degC on average. When used to minimize peak temperature with a fixed area, peak temperature reductions are common. Under a constraint on peak temperature, integrated circuit area is reduced by 9.9% on average
38052408
Towards a practical, secure, and very large scale online election
We propose a practical and secure electronic voting protocol for large-scale online elections. Our protocol satisfies a large set of important criteria that has never been put together in a single protocol before. Among all electronic voting schemes in the literature, Sensus, a security-conscious electronic voting protocol proposed by Cranor and Cytron (1997), satisfies most of our criteria. Sensus has been implemented and used in mock elections. However, Sensus suffers from several major drawbacks. For instance, we show that even if all voters follow the Sensus protocol honestly, some voters' votes may still be replaced with different votes without being detected. Our protocol overcomes these drawbacks.
8200860
Digital imagery for significant cultural and historical materials
Digital imagery for significant cultural and historical materials is an emerging research field that bridges people, culture, and technologies. In this paper, we first discuss the great importance of this field. Then we focus on its four interrelated subareas: (1) creation and preservation, (2) retrieval, (3) presentation and usability, and (4) applications and use. We propose several mechanisms to encourage collaboration and argue that the field has high potential impact on our digital society. Finally, we make specific recommendations on what to pursue in this field.
14843520
Deriving knowledge from figures for digital libraries
Figures in digital documents contain important information. Current digital libraries do not summarize and index information available within figures for document retrieval. We present our system on automatic categorization of figures and extraction of data from 2-D plots. A machine-learning based method is used to categorize figures into a set of predefined types based on image features. An automated algorithm is designed to extract data values from solid line curves in 2-D plots. The semantic type of figures and extracted data values from 2-D plots can be integrated with textual information within documents to provide more effective document retrieval services for digital library users. Experimental evaluation has demonstrated that our system can produce results suitable for real-world use.
19646455
The upper bound of essential cyclomatic numbers of hypergraphs
Abstract The essential cyclomatic number of a hypergraph is the maximum number of independent essential cycles of the hypergraph. In this paper, we first prove a general upper bound for the cyclomatic number in terms of the size, order and edge-size of a hypergraph. Then we give a sharp upper bound for ( n −2)-uniform hypergraphs of order n by solving an extremal problem of graphs. It is remarkable that this sharp upper bound is not generally achieved by the complete ( n −2)-uniform hypergraphs.
12186597
A Power-Saving Multi-Radio Multi-Channel MAC Protocol for Wireless Local Area Networks
Opportunistic spectrum access and adaptive power management are effective techniques to improve throughput, delay performance, and energy efficiency for wireless networks. In this paper, we consider the joint design of opportunistic spectrum access and adaptive power management under the setting of multi-radio nodes and multi-channel wireless local area networks (WLANs) under the distributed coordination function (DCF) mode. This design problem is particularly challenging due to the conflicting nature of the multi-radio capability of a node, i.e., multiple radios improve throughput and delay performance at the cost of increased energy consumption. To address this problem, we propose a power-saving multi-channel MAC protocol (PSM-MMAC), which is capable of reducing the collision probability and the waiting time in the ‘awake’ state of a node, resulting in improved throughput, delay performance, and energy efficiency. The key ideas of PSM-MMAC are the following: we first estimate the number of active links; given this estimation as well as queue lengths and channel conditions, we appropriately select channels, radios, and power states (i.e., awake or doze state); then we optimize the medium access probability in p-persistent CSMA used in the data exchange. Another contribution of this paper is an analytical model that characterizes the throughput performance. Simulation results validate the accuracy of our analytical model and show that our proposed protocol is able to significantly improve both throughput and energy efficiency.