一种基于小波变换的图像压缩方法

提出一种基于小波变换的灰度图像数据压缩编码方法,基本思路是利用小波变换实现图像的多分辨分解,用矢量量化（ＶＱ）对分解后的图像进行编码,在矢量量化ＬＢＧ算法的初始码书的选取中根据矢量中各分量的特性提出一种改进的随机选取法,避免了可能的胞腔不均现象,提高了码书的质量,而且重构的图像质量也有所提高。     

基于MF-RC500的射频卡读写系统设计

MF-RC500完整的集成13.56MHz下所有类型的被动非接触式通信方式和协议,是一种先进的集成式射频芯片,本文设计一种基于MF-RC500的射频卡读写系统,系统主控制器采用具有超低功耗特性的MSP430系列微控制器.首先依据系统框图设计硬件电路系统,设计了MSP430f1232与MF-RC500的接口以及天线和EMC回路:另外设计了系统初始化程序及射频卡处理程序.该系统可读写Mifare Pro、Mifare One、Mifare Light等射频卡,具有一定的通用性.     

Learning a Maximum Margin Subspace for Image Retrieval

One of the fundamental problems in Content-Based Image Retrieval (CBIR) has been the gap between low-level visual features and high-level semantic concepts. To narrow down this gap, relevance feedback is introduced into image retrieval. With the user-provided information, a classifier can be learned to distinguish between positive and negative examples. However, in real-world applications, the number of user feedbacks is usually too small compared to the dimensionality of the image space. In order to cope with the high dimensionality, we propose a novel semisupervised method for dimensionality reduction called Maximum Margin Projection (MMP). MMP aims at maximizing the margin between positive and negative examples at each local neighborhood. Different from traditional dimensionality reduction algorithms such as Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA), which effectively see only the global euclidean structure, MMP is designed for discovering the local manifold structure. Therefore, MMP is likely to be more suitable for image retrieval, where nearest neighbor search is usually involved. After projecting the images into a lower dimensional subspace, the relevant images get closer to the query image; thus, the retrieval performance can be enhanced. The experimental results on Corel image database demonstrate the effectiveness of our proposed algorithm.     

Lot-sizing scheduling with batch setup times

This paper is concerned with scheduling independent jobs on m parallel machines in such a way that the makespan is minimized. Each job j is allowed to split arbitrarily into several parts, which can be individually processed on any machine at any time. However, a setup for uninterrupted s_j time units is required before any split part of job j can be processed on any machine. The problem is strongly NP-hard if the number m of machines is variable and weakly NP-hard otherwise. We give a polynomial-time -approximation algorithm for the former case and a fully polynomial-time approximation scheme for the latter. AMS Subject Classifications: 68M20 · 90B35 · 90C59     

Microstructure of SiCp-reinforced A356 cast Al metal-matrix composite

The microstructure of SiCp-reinforced A356 cast Al metal-matrix composite (MMC) has been investigated by means of transmission electron microscopy and energy-dispersive X-ray analysis. It is found that the MMC contains -SiC, ( + ₂) SiC composite, eutectic Si, GP zones of Si sequence, a new J phase and the amorphous phase Al _x Si₉Ca₂. The ₂-SiC is lathlike with a triclinic crystal structure having a=0.308 nm, b=0.305 nm, c=1.262 nm, = 93.8 °, = 90.0 °, and = 60.0 °. The J phase is bulk-like with a C-face-centred orthorhombic crystal structure having a = 0.680 nm, b = 1.170 nm and c = 0.826 nm.     

Distribution of ground stress on Puhe Coal Mine

Puhe Coal Mine is a typical Tertiary coal in Shenbei mining area. With an increase in mining depth, tectonic stress field becomes more complex, leading to increased deformation and failure of the soft rock roadway. Stress becomes an important factor of mine safety and stability. This paper analyzes the distribution of the regional tectonic field, and determines the distribution of situ stress measurement through measuring the ground stress field in the main mining area level of Puhe Coal Mine using stress relief method. The acquired in situ stress data at different locations and depths provide a reference for the rational arrangement of the stop and mine roadway supporting design, which are of great significance for the efficient safety production of the mine.     

ISHair: Importance Sampling for Hair Scattering

We present an importance sampling method for the bidirectional scattering distribution function (bsdf) of hair. Our method is based on the multi‐lobe hair scattering model presented by Sadeghi et al. [ [SPJT10] ]. We reduce noise by drawing samples from a distribution that approximates the bsdf well. Our algorithm is efficient and easy to implement, since the sampling process requires only the evaluation of a few analytic functions, with no significant memory overhead or need for precomputation. We tested our method in a research raytracer and a production renderer based on micropolygon rasterization. We show significant improvements for rendering direct illumination using multiple importance sampling and for rendering indirect illumination using path tracing.     

空冷型光伏光热一体化系统的实验研究

对空冷型单晶硅光伏光热一体化系统进行了实验研究,充分肯定了光伏光热一体化系统对于提高电效率和利用热能的作用.通过对带有风机的空冷型强制对流单晶硅电池板与空冷型自然对流单晶硅电池板两者的电效率、净电效率和热效率的比较,探讨风机对于电池板散热的效果以及对其各项效率的影响.     

压电阻尼复合材料在船舶承力轴承减振中的应用研究

为了使船舶承力轴承具有良好的降噪减震效果,采用环氧树脂为基体,PMN(铌镁锆钛酸铅)为压电相,导电炭黑为导电相制备了0-3型压电复合材料,DMA(dynamic mechanical analyzer)测试结果表明,PMN/导电炭黑/环氧树脂复合材料具有良好的阻尼性能。以该复合材料作为阻尼层,制备船舶承重轴承缩比模型,阻尼性能研究结果显示结构试件的阻尼性能主要由0-3型压电复合材料提供,试件整体结构阻尼因子为0.415 6,振级落差的数值在4.64～16.79dB,具有良好阻尼减振效果。     

自适应背景筛选的运动对象检测算法

针对传统帧差法和背景差分法对运动对象检测不准确等不足,提出了一种自适应背景筛选的运动对象检测算法。该算法在采用帧差法构建的背景中标注出原图存在运动对象的区域,筛选当前运动对象区域未被标注且距当前时刻最近的背景与当前帧进行差分,从而提取前景运动目标。与帧差背景结合方法相比,该方法能更好解决因运动对象静止后融入背景建模而导致的检测对象不准确问题,且算法简单,易于实现,满足实时监控要求。实验结果验证了该算法的有效性。