Similarity measures,penalty functions,and fuzzy entropy from new fuzzy subsethood measures

In this study, we discuss a new class of fuzzy subsethood measures between fuzzy sets. We propose a new definition of fuzzy subsethood measure as an intersection of other axiomatizations and provide two construction methods to obtain them. The advantage of this new approach is that we can construct fuzzy subsethood measures by aggregating fuzzy implication operators which may satisfy some properties widely studied in literature. We also obtain some of the classical measures such as the one defined by Goguen. The relationships with fuzzy distances, penalty functions, and similarity measures are also investigated. Finally, we provide an illustrative example which makes use of a fuzzy entropy defined by means of our fuzzy subsethood measures for choosing the best fuzzy technique for a specific problem.     

Method for improving the position precision of a hydraulic robot arm: dual virtual spring–damper controller

Recently, control approaches for a hydraulic robot in the field of robotics have attracted considerable attention owing to their high power-to-weight ratio. Many studies on behavior and control exploiting the advantages of hydraulic robots have been pursued. Application to hydraulically actuated systems, however, is not straightforward due to the nonlinear internal dynamics of the actuators. This paper presents a relatively simple method to improve the position precision of a hydraulic robot arm. We propose a simple control method concept based on a virtual spring–damper (VSD) controller, which enables the robot to realize a desired position. The main advantage of the VSD control is its simple calculation method, which eliminates the need to solve the Jacobian pseudo-inverse or ill-posed inverse kinematics. In this study, experiments were conducted to identify the problems in previous study results and evaluated the applicability of VSD control to the hydraulic robot arm. A relatively simple method was proposed to solve these problems and to verify improvements in the position precision. The proposed method is the dual VSD controller in which an additional VSD model is applied to the elbow, in addition to the conventional VSD model connected to the wrist. The effectiveness of the proposed control scheme is demonstrated in experimentation with the hydraulic robot arm.     

Effects of catalyst aging on the activity and selectivity of commercial three-way catalysts

A Pd catalyst is particularly effective for the oxidation of CO and C₃H₆ at low temperatures, while the Pt/Rh/Ce catalyst is active for NO reduction. The TWC activity of both catalysts generally decreased as the catalyst mileage increased. However, the NO reduction activity was less affected by catalyst aging compared to the oxidation reactions. The selectivity of the catalysts in favor of the CO–O₂ reaction (vs. C₃H₆–O₂ reaction) in the O₂ partitioning experiments became less pronounced as the catalyst aged. The NO partitioning experiments reveal the superior capability of H₂ in NO reduction to the other reductants (CO and C₃H₆) examined in the present study. The reactivities of NO with both H₂ and CO were found to decrease upon catalyst aging, resulting in decreased overall NO removal activity.     

On the origin of electrodeposition mechanism of ZnO on ITO substrate

Zinc oxide (ZnO) was potentiostatically deposited on indium tin oxide (ITO) substrates. Comparing of the theoretical mass/charge ratio with experimental value measured byin-situ electrochemical quartz crystal microbalance, the origin of deposition mechanism of ZnO could be explained as follows: (i) surface pH enhancement due to the adsorption of hydroxide ion; (ii) the formation of intermediate species (i.e., zinc hydroxide (Zn(OH)⁺); (iii) ZnO deposition with production of water.Ex-situ morphological and structural analyses by scanning electron microscope and X-ray diffraction strongly supported the deposition mechanism of ZnO. This also showed that hexagonal shaped ZnO islands were first formed on ITO cathode and grew into compact ZnO films, and the formation behaviour of ZnO was clearly explainedvia analysis of the profile of measured current.     

Dual permeation of acid dyes through nylon 6 membrane

Permeation of acid dyes in nylon 6 membrane was measured and analyzed by the dual sorption and diffusion mechanism, comprising partition and Langmuir-type modes. The results were compared with our previous work on diffusion in the same system by the film roll method. Diffusion coefficients of both dye species were found to be similar in magnitude.     

A centrifugal force-based serpentine micromixer (CSM) on a plastic lab-on-a-disk for biochemical assays

In this paper, a centrifugal force-based serpentine micromixer (CSM) on a plastic lab-on-a-disk (LOD) for biochemical assay was designed, fabricated, and fully characterized with numerical and experimental methods. The CSM comprised two inlets, an outlet, and a serpentine microchannel composed of five circumferential channels with connecting radial channels in one layer. The centrifugal force induced in the rotating disk thoroughly mixed the sample and reagent together throughout the serpentine microchannel of the CSM. Despite its simple geometry, effective mixing performance was achieved inside the CSM because of transverse secondary flows and the three-dimensional stirring effect in the microchannel. Numerical simulation showed that the interfaces of the two streams inside the circumferential microchannel were efficiently stirred by the induced transversal velocity field. The plastic LOD was fabricated by CNC-micromilling on one layer of the thermoplastic substrate, followed by thermal bonding with a cover plastic substrate. Mixing performance of the CSM was also investigated experimentally by means of colorimetric analysis using phenolphthalein. High levels of distributive mixings were obtained within a short required mixing length. As a proof-of-concept example, a biochemical assay of albumin level was successfully determined with the help of the LOD containing the CSM. Owing to the mass-producible simple geometry, excellent mixing performance, and convenience, the CSM can be applied to biochemical assays based on the centrifugal microfluidics.     

An M-ary detection approach for asset allocation

We develop a continuous-time asset allocation model which incorporates both model uncertainty and structural changes in economic conditions. A “dynamic” M-ary detection framework for a continuous-time hidden Markov chain partially observed in a Gaussian process is used to model the price dynamics of the risky asset and the hidden states of an economy. The goal of an investor is to select an optimal asset portfolio mix so as to maximize the expected utility of terminal wealth. Filtering theory is used first to turn the problem into one with complete observations and then to derive M-ary detection filters for the hidden system. The Hamilton-Jacobi-Bellman dynamic programming approach is used to solve the asset allocation problem with complete observations. An explicit solution is obtained for the power utility case.     

A BSDE approach to a risk-based optimal investment of an insurer

We discuss a backward stochastic differential equation, (BSDE), approach to a risk-based, optimal investment problem of an insurer. A simplified continuous-time economy with two investment vehicles, namely, a fixed interest security and a share, is considered. The insurer’s risk process is modeled by a diffusion approximation to a compound Poisson risk process. The goal of the insurer is to select an optimal portfolio so as to minimize the risk described by a convex risk measure of his/her terminal wealth. The optimal investment problem is then formulated as a zero-sum stochastic differential game between the insurer and the market. The BSDE approach is used to solve the game problem. It leads to a simple and natural approach for the existence and uniqueness of an optimal strategy of the game problem without Markov assumptions. Closed-form solutions to the optimal strategies of the insurer and the market are obtained in some particular cases.     

Sex Hormones Function as Sex Attractant Pheromones in House Mice and Brown Rats

Sex hormones of mammals control the expression of sexual characteristics and bodily functions. The male hormone testosterone and the female hormones progesterone and estradiol are known to occur in urine markings of mice. Here, we show that all three hormones are also present in urine of brown rats, and that they are effective sexual communication signals (pheromones) that elicit attraction behavior of prospective mates in both brown rats and house mice. When added as lures to trap boxes in field experiments, synthetic testosterone, for example, increased captures of adult female mice 15‐fold, and a blend of progesterone and estradiol increased captures of male mice eightfold and male rats 13‐fold. Remarkably, these hormones increased captures even though the food‐ and pheromone‐based baits to which they were added had previously been shown to be superior to current commercial rodent attractants. We predict that these sex hormones will function as sex attractant pheromones in diverse taxa.