基于定向拉普拉斯模型的图像放大方法

针对传统插值及PDE模型放大方法的缺点,提出一种具有边缘增强作用的基于定向拉普拉斯模型的图像放大方法。该方法以传统插值放大方法为初值,然后经边缘增强的定向拉普拉斯PDE方程反复迭代的扩散作用实现图像放大。实验结果表明,该算法是一种有效的保持边缘和细节的图像放大方法,在客观指标和主观效果上均优于传统双线性插值和P-M方程的方法,是一种有效的图像放大算法。     

Componentwise edge detection by Laplacian operator masks

This note introduces componentwise edge detection technique for Laplacian operator masks. Laplacian operator masks are expressed by means of gradient components. The absolute sums of the gradient components at image points form the gradient image, from which the edges are extracted. The results obtained are comparable to those obtained by the gradient sum and max operators or Sobel and Prewitt masks.     

基于Laplacian算子的小波变换图像融合算法

针对传统融合算法在图像融合时,不能很好地保留源图像信息和边缘信息的缺点,提出了一种基于Laplacian算子的小波变换图像融合算法。该算法利用小波变换对图像进行分解,分解后得到图像的低频系数和高频系数;对高频系数采用基于对两个Laplacian模板算子卷积结果相比较并进行筛选的融合规则;对低频系数采用基于拉普拉斯清晰度评价函数和8邻域局部方差相结合的融合规则;最后进行小波逆变换得到融合图像。对实验结果结合主观和多种客观评价方法进行分析。结果表明,该改进算法与传统融合算法相比融合效果更好,融合图像具有边缘信息丰富、图像清晰度高等优点。     

Optimally sensitive networks

The constraints on LC transfer-function coefficients are investigated for networks to be optimally sensitive according to Schoeffler's criterion considered by Leeds and Ugron.     

An Optimally Controlled Respirator

An optimally controlled respirator was developed. It has three main features: 1) ventilation is controlled by the patient's metabolic rate from continuously measured C02 output, 2) physiologic dead space approximated as a linear function of tidal volume is used to estimate alveolar ventilation, and 3) respiratory rate is computed to minimize ventilatory work.     

Sharing Memory Optimally

Efficient design of service facilities, such as data or computer networks that meet random demands, often leads to the sharing of resources among users. Contention for the use of a resource results in queueing. The waiting room is a part of any such service facility. The number of accepted service requests per unit of time (throughput), or the fraction of the time the servers are busy (utilization), are often used as performance measures to compare designs. Most common models in queueing theory consider the design of the waiting rooms with the assumption that, although individual requests may differ from one another, they are statistically indistinguishable. However, there are several instances where available information allows us to classify the requests for service into different types. In such cases the design of the service facility not only involves the determination of an optimum size for the waiting room but also the rules of sharing it among the different types. Even with a fixed set of resources, the rules of sharing them can influence performance. In data networks (or computer networks) the "waiting room" consists of memory of one kind or another. Messages (jobs) destined for different locations (processors) sharing common storage is an important example of shared use of memory. Recently, Kleinrock and Kamoun have modeled such use of memory and computed the performance of various policies for managing the allocation of memory to several types of users. Decisions to accept or reject a demand for service were based on the number of waiting requests of each type. However, the optimal policy was not determined even in the case where there were only two types of users. We determine the structure of optimal policies for the model considered with three types of users. The optimal policy consists of limiting the number of waiting requests of each type, and reserving a part of the memory to each type.     

Optimally adaptive transform coding

The optimal linear block transform for coding images is well known to be the Karhunen-Loeve transformation (KLT). However, the assumption of stationarity in the optimality condition is far from valid for images. Images are composed of regions whose local statistics may vary widely across an image. While the use of adaptation can result in improved performance, there has been little investigation into the optimality of the criterion upon which the adaptation is based. In this paper we propose a new transform coding method in which the adaptation is optimal. The system is modular, consisting of a number of modules corresponding to different classes of the input data. Each module consists of a linear transformation, whose bases are calculated during an initial training period. The appropriate class for a given input vector is determined by the subspace classifier. The performance of the resulting adaptive system is shown to be superior to that of the optimal nonadaptive linear transformation. This method can also be used as a segmentor. The segmentation it performs is independent of variations in illumination. In addition, the resulting class representations are analogous to the arrangement of the directionally sensitive columns in the visual cortex.     

The surface Laplacian operator of the potentials on a bounded volume conductor has a unique inverse

In the discussion on the use of the surface Laplacian (SL) of the distribution of bioelectric potentials on the body surface, the question remained open whether a complete specification of the SL of the potential over the surface bounding a volume conductor would uniquely specify the potential on that surface up to a constant. This paper reports that this is indeed the case. In addition, it is shown that the integral of the SL over a closed surface is zero, a property that may serve as a check on the accuracy of any numerical approximation of the SL.     

Optimally Interleaved Signals for SFN

This paper focuses on how designing transmit signals improves performance of single frequency networks (SFNs), employing multiple distributed transmit antennas. Considering the effect of multipath fading, pairwise error probability conditioned on shadowing is derived to show that the achievable diversity order of SFNs increases as the number of resolvable channel taps between transmit and receive antennas increases. One transmit signal based on interleaved-partition subcarrier grouping is proposed to obtain the achievable diversity order. Further, we show that different interleaving methods result in different performance due to asynchronous delays caused by unequal distances between distributed transmit antennas and mobile receivers. To optimize the proposed transmit signal, one interleaving scheme, establishing a tradeoff between mobile receivers' location and performance, is introduced in terms of the asynchronous delays. Simulation results are presented in a representative scenario to demonstrate the performance gains offered by the proposed optimum transmit signal. The proposed scheme does not introduce any changes at the mobile receivers.     

An Optimally Fair Coin Toss

We address one of the foundational problems in cryptography: the bias of coin-flipping protocols. Coin-flipping protocols allow mutually distrustful parties to generate a common unbiased random bit, guaranteeing that even if one of the parties is malicious, it cannot significantly bias the output of the honest party. A classical result by Cleve (Proceedings of the 18th annual ACM symposium on theory of computing, pp 364–369, 1986) showed that for any two-party \(r\)-round coin-flipping protocol there exists an efficient adversary that can bias the output of the honest party by \(\varOmega (1/r)\). However, the best previously known protocol only guarantees \(O(1/\sqrt{r})\) bias, and the question of whether Cleve’s bound is tight has remained open for more than 20 years. In this paper, we establish the optimal trade-off between the round complexity and the bias of two-party coin-flipping protocols. Under standard assumptions (the existence of oblivious transfer), we show that Cleve’s lower bound is tight: We construct an \(r\)-round protocol with bias \(O(1/r)\).     

An Optimally Energized Cardiac Pacemaker

Batteries that power implanted cardiac pacemakers deteriorate because of energy drain and permeation of body fluids. They must, therefore, be replaced periodically, most often by means of an operation. In this paper, the stimulating waveform that draws the least amount of energy from the battery and also delivers the minimum energy to a heart cell is derived. It is shown that a 31-percent reduction in energy (with respect to that required by the standard rectangular pulse) can be achieved if the pulse duration is about twice the cell time constant. Moreover, it is demonstrated that the required energy is insensitive to pulse-duration variations (due to component changes). An easily synthesized suboptimal approximation is developed and requires only slightly more energy than the optimal pulse.     

Optimally sensitive controller for digital systems

A scheme is developed which allows an optimal control policy to be maintained in cases where the parameters of the controlled system deviate by a small amount from the values expected. This is achieved by augmenting the nominally correct controller design to allow updating of the system control vector on the basis of observed deviations from the ideal state trajectory.     

Optimally aggregated models of high-order systems

A straightforward scheme for generating optimally aggregated models of high-order systems is presented. The simplicity of the scheme is a direct result of generalising the model forms under consideration. The interesting case of optimal projection along invariant subspaces is a special case. Finally, the notion of quasioptimal aggregated models is introduced, which reduces computation considerably.     

An Optimally Designed Process for Submicrometer MOSFET's

An n-channel MOS process has been optimized to yield desirable characteristics for submicrometer channel-length, MOSFET's. Process/device simulation is extensively used to find an optimized processing sequence compatible with typical production-line processes. The simulation results show an excellent agreement with experimental data. We have obtained long-channel subthreshold characteristics, saturation drain characteristics up to 5 V, and a minimized substrate bias sensitivity for transistors with channel lengths as small as 0.5 /spl mu/m. The short-channel effects have been also minimized. A new self-aligned silicidation technology has been developed to reduce the increased resistance of diffused layers with down-scaled junction depths.     

一种改进的链路容量优化路由策略

设计能够适应高移动环境下的空基自组网路由协议是目前研究的重点方向。提出了基于负载均衡的优化路由协议,该协议在获得位置信息的前提下,首先预测出通信链路的有效时间,然后在满足数据的时延、带宽以及链路有效性等多约束条件下,路由协议以均衡节点负载为优化目标,使得网络节点都能合理承担数据传输任务。仿真结果表明,设计的路由协议能够保证网络节点合理分担传输任务,充分利用链路资源,提高网络的吞吐量。     

一种新的最佳多维星座成形算法

本文提出一种新的实现对多维星座最佳成形区域—截断多圆柱映射的编码和译码算法，该算法采用循环和移位操作大幅度地减少了存储空间，适合于用数字信号处理器实现。     

拉普拉斯加权聚类算法

 本文提出了一种用于聚类分析的加权聚类算法,通过利用拉普拉斯权,将聚类对象之间的结构信息自动转换为对象的权重.由于拉普拉斯权能够描述数据的邻域结构,从而能够更好的聚类.该加权聚类算法在性能上比经典聚类算法有较大改进,还具有对孤立点鲁棒、适合类别不平衡数据聚类、对聚类个数不敏感等优点.人工数据集以及UCI标准数据集上的实验证实了本文算法的可行性和有效性.     

Optical Fiber Direct Detection Receivers Optimally Tolerant to Jitter

A technique for optimizing the performance of directdetection optical communication receivers for binary signaling in the presence of signal dependent noise, additive noise, and intersymbol interference by minimizing a Chernoff bound on the average error probability is extended to accommodate timing jitter. Receivers are identified which provide significantly improved performance compared to conventional designs, and the performance of a jitter-optimized receiver is shown to be relatively insensitive to variations in the jitter level.     

液晶盒厚度的反射光谱拟合法测量

介绍了一种测量液晶盒厚度的新型光学方法——反射光谱拟合法。理论上,液晶盒的反射光谱呈正弦曲线,且曲线取极值时对应入射光波长大小值取决于所用液晶盒的厚度。反之亦然,当得知液晶空盒的反射光谱时,可以根据曲线取极值时入射光波长的值来获得待测液晶盒的厚度。软件用来搜索与实验测试数据相互吻合的液晶盒厚度。该技术以白光作为液晶盒的前端光源,且白光入射角为0°。结果表明,该方法测量范围5 ～30μm,测量重复误差0 .1μm以下。实验中,光纤光谱仪用来测试反射光谱,并通过USB接口将其传输到计算机。该方法的优点是它可以在0 .1 s内测试液晶盒表面任意点处的厚度,有较强的使用价值。