Similarity-based ranking and query processing in multimedia databases

Since media-based evaluation yields similarity values, results to a multimedia database query, Q(Y₁,…,Y_n), is defined as an ordered list S_Q of n-tuples of the form X₁,…,X_n. The query Q itself is composed of a set of fuzzy and crisp predicates, constants, variables, and conjunction, disjunction, and negation operators. Since many multimedia applications require partial matches, S_Q includes results which do not satisfy all predicates. Due to the ranking and partial match requirements, traditional query processing techniques do not apply to multimedia databases. In this paper, we first focus on the problem of “given a multimedia query which consists of multiple fuzzy and crisp predicates, providing the user with a meaningful final ranking”. More specifically, we study the problem of merging similarity values in queries with multiple fuzzy predicates. We describe the essential multimedia retrieval semantics, compare these with the known approaches, and propose a semantics which captures the requirements of multimedia retrieval problem. We then build on these results in answering the related problem of “given a multimedia query which consists of multiple fuzzy and crisp predicates, finding an efficient way to process the query.” We develop an algorithm to efficiently process queries with unordered fuzzy predicates (sub-queries). Although this algorithm can work with different fuzzy semantics, it benefits from the statistical properties of the semantics proposed in this paper. We also present experimental results for evaluating the proposed algorithm in terms of quality of results and search space reduction.     

A Simultaneous Search Problem

We introduce a new search problem motivated by computational metrology. The problem is as follows: we would like to locate two unknown numbers x,y ∈ [0,1] with as little uncertainty as possible, using some given number k of probes. Each probe is specified by a real number r∈ [0,1] . After a probe at r , we are told whether x≤ r or x \geq r , and whether y≤ r or y\geq r . We derive the optimal strategy and prove that the asymptotic behavior of the total uncertainty after k probes is 13/7 2 ^-(k+1)/2 for odd k and 13/10 2 ^-k/2 for even k . Received November 11, 1996; revised October 2, 1997, and July 13, 1998.     

Investigation of point-to-point performance test of touch trigger probes on coordinate-measuring machines

A major factor contributing to the total measuring error of coordinate measuring machines (CMMs) is the performance of the probing sub-system. Probing test methods are typically used to detect errors due to the probing sub-system. The probe performance evaluation method specified in the ANSI B89 standard is investigated in this paper. The sampling plan associated in the probe performance evaluation was tested by using experimental probing data from a CMM. Research findings indicate that the performance of touch trigger probes is overestimated due to a systematic bias in the vertical direction of the best-fit reference ball center in the probe performance test. A two-latitude sampling plan synthesis method based on a pretravel model for touch trigger probes is proposed in this paper. The proposed method can be used to accurately identify the reference ball center in the performance test of touch trigger probes.     

基于DNA算法的独立数问题的求解*

在构造了一种链接链及一种新型的“类发夹式”探针的基础上,给出了图的独立数问题的一种DNA算法。利用顶点的简单编码及链接链,该算法直接生成数据池,使用常规的生物操作即可完成解空间的产生及最终解的分离。     

快速流化床内探头设置方向对传热系数测量结果的影响

本文在一高8m,直径186mm 的快速流化床中采用小型电加热探头测定了床层与换热面之间的局部传热系数,实验中通过将探头向上和向下设置考察了探头设置方向对局部传热系数的影响,实验表明探头在床中的设置方向不同将对传热系数的测定值产生一定的影响:另外在同一床层浓度下,操作气速和固体循环速率的变化将对传热系数产生直接的影响     

Polyaniline as a Gas-Sensor Material

Polyaniline (PANI) was synthesized by oxidative polymerization of aniline using ammonium persulfate in an acid medium. The polyaniline salt was converted to base form by treatment with ammonium hydroxide. The polyaniline base was dissolved in N-methyl pyrrolidone (NMP) for film casting. The cast film was doped with HCl for obtaining higher conductivity. Both doped and undoped PANI films were characterized by UV-visible, FTIR, and XRD analyses. The electrical conductivity of the PANI film was studied by a four-point probe method at room temperature. Finally, ammonia gas-sensing characteristics of the prepared polyaniline film were studied by measuring the change in electrical conductivity on exposure to ammonia gas at different concentrations. The influence of concentration of acid during polymerization of aniline and dopant concentration on the gas sensing characteristics of PANI film are reported in this paper.     

探针组分对紫外光固化材料表面性能的影响

光固化快速成型技术（Stereolithography，SL）采用材料逐层固化累加法来形成三维实体模型，因此固化材料的表面性质对层与层之间的结合力有着非常大的影响。为了研究环氧丙烯酸酯类紫外光固化材料所形成表面的性质及影响因素，通过使用探针组分，对固化涂层进行接触角的测定和表面能的计算，并用衰减全反射-傅立叶变换红外光谱（Attenuated total reflectance-Fourier transforminfrared，ATR-FTIR）对固化膜的表面组成进行了表征。结果表明：固化过程中组分发生了迁移，其含量由表及里存在分布不均现象，最终对固化层的表面能产生了影响，且质量分数为0．01％的探针组分含量就能使表面能的变化显得相当敏感（Deuchem 467使涂层表面能由51．32mJ m^-2骤降至35．05mJm^2）.不同结构的探针组分迁移程度有差异，使涂层表面能发生了不同的改变。同时，组分的迁移程度也与涂层的两种接触介质（固化气氛与基材）的性质有关，引起涂层气氛面和基材面表面能的较大差异。     

靶标成像双目视觉坐标测量建模

提出了一种利用手持式靶标实现双目视觉三维坐标测量建模的新方法。利用空间透视变换建立了非线性测量模型．介绍了基于牛顿非线性迭代的测量方程的求解方法。以矩阵分析理论为基础，讨论了影响测量方程求解的因素，并提出了方法中重要部件手持式靶标上特征点分布的基本约束条件，为这一方法在实际应用中获得较高的测量精度提供了较为完善的理论分析依据。通过数值分析与计算，验证了理论分析的正确性和这一方法应用的可行性。     

Effect of interactions between voltage and current harmonics on the net harmonic current produced by single phase non-linear loads

The effect of the interaction between both load voltage and current harmonics on the net harmonic current produced by different types of single phase non-linear loads is investigated. Two types of loads are considered: the fluorescent lamps' load and single phase diode bridge rectifiers' load. Studies are done on each load alone and then on the combination of both. The electromagnetic transient program has been used to model these loads. The computer simulations are supported by laboratory testing. The main conclusion of this work is that neglecting the interactions between both voltage and current harmonics will result in incorrect estimation of the harmonic current produced by these loads. Also it is concluded that using a combination of different types of loads can result in a reduction of the current and voltage distortions.