Empirical comparison of image retrieval color similarity methods with human judgment

It is important to verify assumptions and methods of image retrieval against actual human behavior. A study was conducted to compare similarity methods of color histograms against human assessment of similarity. The similarity methods tested include basic histogram intersection, center histogram matching, locality histogram matching, and size-weighted histogram matching. 161 subjects participated in the empirical study. The findings, based on Spearman correlation analysis, showed that both the basic histogram intersection method and size-weighted histogram are very close to human assessment of similarity (Spearman correlation coefficient of 0.915). The other two are not close to human judgment on similarity. This study illustrates an alternative approach to evaluating matching algorithms. Unlike the usual measures of recall and precision, this approach emphasizes human validation. Fewer images are required with the use of statistical testing.     

Design criteria for the crystallization of an organic salt from an aqueous solutionAuslegungsunterlagen zur kristallisation eines organischen salzes aus wässriger Lösung

Results from laboratory experiments and a 500 tonnes per month pilot plant have been used to draw up criteria for designing the crystallization of an organic salt from its aqueous solution. The crystallization kinetics were determined in a continuous forced circulation crystallizer. The experiments in the forced circulation evaporative crystallizer were carried out and evaluated in accordance with the MSMPR (mixed suspension mixed product removal) concept.The residence time was varied between 0.8 and 10 hours, and the density of the suspension between 180 and 870 kg m^?3. It was found that, within the residence time and suspension density ranges studied, growth and nucleation rates have the same dependence on the supersaturation. On the other hand, the nucleation rate decreases with increasing suspension density. If the crystallization kinetics and other design criteria, such as vapour velocity, i.e. supersaturation ratio in the vicinity of the evaporative surface, or height of liquid above the heat exchangers, are taken into account, it is possible to obtain a space—time yield which is five times higher than in the pilot plant, so that the plant to be built can be designed to be correspondingly smaller.     

Frequency discrimination: Assessing global-level and element-level units in memory.

Assessed the retention of memory units for word-like strings of letters using the perceptions of 120 undergraduates in 2 experiments in determining how frequently various letters appeared. A series of strings was presented at 1 of 3 exposure durations. Within the series, the frequencies of occurrence of different strings and of the letters composing the strings were varied orthogonally. Results indicate that, at relatively long exposure durations, Ss could discriminate the frequency of occurrence for both strings and their constituent letters. The formation of global-level (string) memory units was indicated by judgments of string frequency being unaffected by either the frequencies of their component letters or experimental conditions (brief exposures) that prohibited accurate judgment of letter frequency. Although judgments of letter frequency were sometimes biased by the frequency of the strings containing the letters, the success with which the judgments discriminated different levels of letter frequency did not depend on the activation of string-level memory units. Furthermore, Ss' frequency judgments for letters were not predictable from their recall of the strings containing the letters. Results provide evidence for the formation of element-level (letter) memory units. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Application of supercritical fluid chromatography in the quantitative analysis of minor components (carotenes,vitamin E,sterols, and squalene) from palm oil

The application of supercritical fluid chromatography (SFC) coupled with a UV variable-wavelength detector to isolate the minor components (carotenes, vitamin E, sterols, and squalene) in crude palm oil (CPO) and the residual oil from palm-pressed fiber is reported. SFC is a good technique for the isolation and analysis of these compounds from the sources mentioned. The carotenes, vitamin E, sterols, and squalene were isolated in less than 20 min. The individual vitamin E isomers present in palm oil were also isolated into their respective components, α-tocopherol, α-tocotrienol, γ-tocopherol, γ-tocotrienol, and δ-tocotrienol. Calibration of all the minor components of palm as well as the individual components of palm vitamin E was carried out and was found to be comparable to those analyzed by other established analytical methods.     

Layered Diffusion-based Coverage Control in Wireless Sensor Networks

Coverage is an important performance metric for many applications, such as surveillance in wireless sensor networks. Coverage control is used to select as few active nodes as possible from all deployed sensor nodes, such that sufficient coverage of the monitored area can be guaranteed while reducing the energy consumption of each individual sensor node to prolong the network lifetime. This paper classifies three types of coverage control protocols based on the available information about nodes’ distances or locations, and reviews several representative protocols for each type. We also propose a new distributed and localized coverage control protocol, called Layered Diffusion-based Coverage Control (LDCC). The LDCC protocol does not require information about the node location coordinates when selecting active nodes. Instead, it exploits hop count information, which is easily obtained in a WSN, to select active sensor nodes. Furthermore, the LDCC protocol is very simple and does not require any sophisticated computation such as distance or covered area computation. Our simulation results show that the LDCC protocol achieves a high coverage ratio while incurring very low message overhead compared with other existing protocols. Furthermore, simulation results suggest that in a large-scale sensor network with medium to large localization errors, LDCC performs even better than location-based coverage control protocols.     

Barrier Lyapunov Functions for the control of output-constrained nonlinear systems

In this paper, we present control designs for single-input single-output (SISO) nonlinear systems in strict feedback form with an output constraint. To prevent constraint violation, we employ a Barrier Lyapunov Function, which grows to infinity when its arguments approach some limits. By ensuring boundedness of the Barrier Lyapunov Function in the closed loop, we ensure that those limits are not transgressed. Besides the nominal case where full knowledge of the plant is available, we also tackle scenarios wherein parametric uncertainties are present. Asymptotic tracking is achieved without violation of the constraint, and all closed loop signals remain bounded, under a mild condition on the initial output. Furthermore, we explore the use of an Asymmetric Barrier Lyapunov Function as a generalized approach that relaxes the requirements on the initial conditions. We also compare our control with one that is based on a Quadratic Lyapunov Function, and we show that our control requires less restrictive initial conditions. A numerical example is provided to illustrate the performance of the proposed control.     

增进城市地区生物多样性——以新加坡模式为例

自 1963 年以来,新加坡开展实施了绿化计划,并经历了从“花园城市”到“花园中的亲生态城市”的演变。为了在新加坡实现生物多样性保护,国家公园局制定了自然保护蓝图,重点介绍该规划实施的关键是利用技术创新。新加坡城市生物多样性指数是一种评价生物多样性成效的自我评估工具,已在全球范围内的多个城市得到应用。     

Friction and Wear Reduction Mechanism of Polyalkylene Glycol-Based Engine Oils

Polyalkylene glycols (PAG) have been explored as a possible base stock for engine oil formulation. The friction, wear, and load-carrying capacity of five different PAG chemistries were evaluated either as a base stock or as formulated oils in pure sliding and sliding-rolling conditions using various laboratory bench test rigs operating under boundary and mixed lubrication regimes. The results were compared against GF-5 SAE 5W-20 and a mineral-based oil. The wear surfaces were also characterized using various surface-sensitive techniques for analysis of tribofilms to understand the mechanism of friction reduction. The results indicated that PAG oils show lower friction/traction coefficients and improved load-carrying capability, depending on the formulation, than those of the GF-5 SAE 5W-20 and mineral-based oil. The adsorption of PAG molecules on the surface appeared to be responsible for the lower friction characteristics.