Image segmentation of a color-blindness plate

One way of testing color vision is with a color-blindness plate (CBP) consisting of a set of brilliant colored dots to form a pattern (a figure) and a set of other colored dots to form a background. Classification of such a type of color image into a pattern and a background with a traditional technique is difficult. Based on a self-organizing feature map and a labeling process as well as spatial distance computation, an effective approach to the segmentation of a CBP image is presented. We describe the principle of a CBP segmentation and then introduce the CBP. The proposed approach is described, and its experimental results are presented. We conclude that the method can segment the CBP image into a pattern and a background successfully.     

并联机床的动力学特性对加工精度影响的分析

为了提高并联机床的加工精度,分析了并联机床的动力学特性对加工精度的影响。根据牛顿—欧拉方程,得到并联机床的动力学方程,解得连杆的驱动力;根据杆件轴向伸长量与受力之间的关系,得到连杆的长度误差;以无长度误差的连杆长度为优化目标,用优化的方法,得到动平台的位姿,并与连杆有长度误差时动平台的位姿比较,得动平台的位姿误差;根据刀具在动平台坐标系中位置,得刀具加工位置误差及对被加工零件精度的影响。结果表明：并联机床连杆的长度误差,引起刀具加工位置误差,使被加工零件产生形位误差和尺寸误差;并联机床电主轴偏心引起连杆的长度误差的扰动,产生刀具加工位置的扰动误差,影响被加工零件的表面粗糙度。     

Fluctuational electromagnetic interaction between a moving particle and a flat surface covered with a thin adsorbed film

The effect of a thin adsorbed film on the fluctuational electromagnetic tangential force of interaction between a moving nanoparticle and a flat solid surface was theoretically studied for the first time in a nonrelativistic approximation. Particular calculations were performed for a metal film on a dielectric and for a dielectric film on a metal. In both cases, the nanoparticle is assumed to be made of a nonmagnetic metal. It is shown that, at a normal temperature, the presence of an adsorbed film may lead to an increase in the tangential friction force by one or two orders of magnitude for a certain relation between the particle distance from the surface and the film thickness. In the case of a dielectric film on a metal substrate, a decrease in the temperature is accompanied by exponential decrease in the viscous friction. For a metal film on a dielectric substrate, the tangential force exhibits a quadratic dependence on the temperature.     

Developing a product–service system through a productisation strategy: a case from the 3PL industry

A Product–Service System (PSS) is created by combing a tangible product and an intangible service into one integrated offering. Thus, a PSS can be achieved by a production company adding intangible services to a product using a servitisation strategy or by a service company adding a tangible product to a service by means of a productisation strategy. The focus of this paper is on the latter. Our work demonstrates a significant gap in the literature in this area. To address this, we adapt an existing PSS conceptual framework as a means to identify the driving and restraining forces considered by a service company as it explored the possibility of pursuing a PSS productisation strategy. The conceptual framework is applied in an exploratory case study with a 3PL service provider. Application of the framework reveals new driving and restraining forces not previously discussed in the literature. Furthermore, it allows a preliminary quantification of the driving and restraining forces using a force field analysis approach. Our work contributes towards the expansion of the empirical knowledge base in the area of PSS.     

Formation of a Nanophase Wetting Layer and Metal Growth on a Semiconductor

Based on the data on the atomic density of a film and degree of its homogeneity during the formation of the interface between 3d transition metals (Cr, Co, Fe, or Cu) and silicon, a new concept of forming a contact between a reactive metal and a semiconductor has been justified. According to this concept, the low-temperature vapor-phase deposition of a metal onto a semiconductor is accompanied by the formation of a two-dimensional nanophase wetting layer of a metal or its mixture with silicon with a thickness of several monolayers, which significantly affects the interface formation and structure. This concept changes a perspective of forming a contact between a metal and a semiconductor substrate: it is necessary to take into account not only the formation of surface phases and clusters and/or the mixing process, but also the effect of elastic wetting of a substrate by the forming phases.     

Similarity solutions for slender dry patches with thermocapillarity

The lubrication approximation is used to investigate slender dry patches in an infinitely wide film of viscous fluid flowing steadily on an inclined plane that is either heated or cooled relative to the surrounding atmosphere. Four non-isothermal situations in which thermocapillary effects play a significant role are considered.Similarity solutions describing a thermocapillary-driven flow with a dry patch that is widening or narrowing due to either gravitational or surface-tension effects on a non-uniformly heated or cooled substrate are obtained, and examples of these solutions, when the substrate temperature gradient depends on the longitudinal coordinate according to a general power law, are presented. When gravitational effects are strong, the solution contains a free parameter, and for each value of this parameter there is a unique solution representing both a narrowing pendent dry patch and a widening sessile dry patch, whose transverse profile has a monotonically increasing shape. When surface-tension effects are strong, the solution also contains a free parameter, and for each value of this parameter there is both a unique solution representing a narrowing dry patch, whose transverse profile has a monotonically increasing shape, and a one-parameter family of solutions representing a widening dry patch, whose transverse profile has a capillary ridge near the contact line and decays in an oscillatory manner far from it.Similarity solutions are also obtained for both a gravity-driven and a constant-surface-shear-stress-driven flow with a dry patch that is widening or narrowing due to thermocapillarity on a uniformly heated or cooled substrate. The solutions in both cases contain a free parameter, and for each value of this parameter there is a unique solution representing both a narrowing dry patch on a heated substrate and a widening dry patch on a cooled substrate, whose transverse profile has a monotonically increasing shape.     

The Variational Form of the Mathematical Model of a Thermal Explosion in a Solid Body with Temperature-Dependent Thermal Conductivity

The variational form of a mathematical model of a thermal explosion has been developed based on a variational formulation of a nonlinear problem of stationary thermal conductivity in a homogeneous solid body. The model takes the temperature dependence of the thermal conductivity of a solid body into account. The presented example of quantitative analysis of the model demonstrates a method for finding the combination of parameters for determining a thermal explosion in a plate with an exponential temperature dependence of the thermal conductivity. At the same time, the analysis allows one to identify the number of steadystate temperature distributions inside a body whose energy release intensifies with a temperature increase.     

Ground-to-Satellite Narrow-Laser-Beam Pointing by Use of a Backscattered Image

A technique for transmitting a narrow laser beam from a ground station to a satellite has been developed. The principle of pointing a laser beam to a distant target in a scattering medium by use of a backscattered laser beam image is described. We calculated the intensity distribution of the image by using a typical model of atmospheric coefficients. The method was applied to transmit a laser beam from a ground station to Engineering Test Satellite-VI. The accuracy of pointing the laser beam to the satellite was approximately 10 murad in this experiment.     

Enhanced three-dimensional reconstruction from confocal scanning microscope images. II. Depth discrimination versus signal-to-noise ratio in partially confocal images

The enhanced depth discrimination of a confocal scanning optical microscope is produced by a pinhole aperture placed in front of the detector to reject out-of-focus light. Strictly confocal behavior is impractical because an infinitesimally small aperture would collect very little light and would result in images with a poor signal-to-noise ratio (SNR), while a finite-sized partially confocal aperture provides a better SNR but reduced depth discrimination. Reconstruction algorithms, such as the expectationmaximization algorithm for maximum likelihood, can be applied to partially confocal images in order to achieve better resolution, but because they are sensitive to noise in the data, there is a practical trade-off involved. With a small aperture, fewer iterations of the reconstruction algorithm are necessary to achieve the desired resolution, but the low a priori SNR will result in a noisy reconstruction, at least when no regularization is used. With a larger aperture the a priori SNR is larger but the resolution is lower, and more iterations of the algorithm are necessary to reach the desired resolution; at some point the a posteriori SNR is lower than the a priori value. We present a theoretical analysis of the SNR-toresolution trade-off partially confocal imaging, and we present two studies that use the expectationmaximization algorithm as a postprocessor; these studies show that a for a given task there is an optimum aperture size, departures from which result in a lower a posteriori SNR.     

An inspection policy for a deteriorating single-unit system characterized by a delay-time model

This paper develops a method for determining the discrete time points of inspection for a deteriorating system which is under condition-based maintenance. The system is regarded as a single component unit, and it has the following states: a normal state, a symptom state and a failed state. A delay-time model is utilized in order to describe the transition of the states. The transition time from a normal state to a symptom state and the transition time from a symptom state to a failed state are assumed to obey independent and identically distributed probability density functions respectively. Two types of probabilities with respect to inspections are considered: failed-dangerous (FD) probability or type I error that a system is wrongly diagnosed as in a normal state when the system is actually in a symptom state and failed-safe (FS) probability or type II error that a system is wrongly diagnosed as in a symptom state when the system is actually in a normal state. The determination method is formulated to minimize the long-run average cost per unit time with a constraint on inspection time. The nature and sensitivity of the proposed method is investigated under varying FD and FS probabilities and coefficients of variation.     

钢筋混凝土异形柱空间框架抗倒塌试验研究

预知结构在偶然荷载作用下的失效机理和提供新荷载路径是异形柱框架结构抗倒塌设计的重要内容。进行1/3比例的两层3×2跨的底层边柱、角柱的突然失效试验及拟静力倒塌试验。分析钢筋混凝土异形柱空间框架的试验现象、裂缝分布、破坏过程及荷载-位移等,进行异形柱空间框架受力过程分析,研究异形柱空间框架结构的受力机制转换过程。研究结果表明:动力效应对异形柱空间框架的影响效果并不显著。试验中没有出现钢筋被拔出现象,裂缝主要集中在竖向构件支座处;异形柱空间框架的边柱、角柱倒塌破坏过程均经历了弹性阶段、弹塑性阶段、塑性阶段和悬链线阶段,边柱表现的悬链线效应远大于角柱的;楼板及梁的钢筋产生的悬链线效应在异形柱空间框架抗倒塌中发挥重要作用。     

Near-field optical taper antennas fabricated with a highly replicable ac electrochemical etching method

This paper describes a novel chemical etching method to fabricate high quality near-field optical antennas-tapered metallic tips-from gold wire in a reproducible way for optically probing a specimen on the nanoscale. A new type of an electrochemical cell is introduced and different dc and ac etching regimes are studied in detail. The formation and dynamics of a meniscus around a gold wire immersed in an electrolyte when supplying a square wave voltage are considered. We show that in situ etching current kinetics allows one to improve a yield of tips with a well-defined geometry up to 95% by filtering these on the basis of a cutoff current and a power spectrum of etching current fluctuations. As a quantitative measure for estimating the yield we introduce a probability to find tips with curvature radii falling in the range of interest. Testing the tips for a plasmonic effect is implemented with tip-enhanced Raman spectroscopy and sub-wavelength imaging of a thin fullerene film.     

Application of a new orthogonal-flux-type amorphous core tohigh-frequency parametric inverters and three-phase measuringtransformers

The fundamentals of a parametric oscillator using an orthogonal-flux-type amorphous core are described, and several applications are proposed. The parametric oscillator circuit has a power-conversion efficiency of 42% and automatic overcurrent protection. The flux distribution calculated by the finite-element method (FEM) suggests that the discharge of a tuning capacitor generates a circulating flux in a leg of the core. The parametric oscillator, a self-oscillating invertor using a Royer circuit, shows an efficiency of 47% at 18.5 kHz and offers overcurrent protection. As a separately controlled parametric inverter, it operates at a frequency of 74 kHz and shows an efficiency of 14% at the maximum output power of 11 W. It can also be used as a potential transformer and as a current transformer in a three-phase system     

Drive to generate digital current for control vertical field in asmall Tokamak

The horizontal position of a small Tokamak plasma has been controlled by a circuit to generate the control vertical field. The circuit must respond quickly to the position signal from a feedback circuit and feed a large current in a short time. We have assembled the circuit to generate a digital current called a drive. The drive includes several units, and each unit is made up of a capacitor, a transistor, a protective resistor and a comparator. We have installed the drive on a small Tokamak, the Hamana-T and obtained satisfactory results. The performance of the drive is described     

Generation of long-range nondiffracting narrow light beams

A type of nondiffracting narrow light beam that propagates across a long range with a narrow beamwidth is presented. This beam is formed by a distorted concave spherical wave front that can be generated by a Galilean transmitting telescope with an eyepiece that has a spherical aberration. We observed an unusual image with a striped pattern in the laser beam's atmospheric backscatter that provided an opportunity to examine this effect. We demonstrate the mechanism of the generation and the characteristics of the long-range nondiffracting beam. The results show that a nondiffracting core beam with a width of the order of millimeters with a propagation distance of the order of a kilometer is generated by a 10-cm-diameter laser beam.     

Digitally controlled linear-in-dB variable-gain amplifier for high-frequency applications

A design technique to implement a digitally controlled dB-linear variable-gain amplifier (VGA) for high-frequency applications is presented. The design approach is applicable to current-steering VGAs and is based on a digital gain control circuit that operates as a nonlinear digital-to-analogue converter to achieve a digitally controlled dB-linear gain control characteristic. Using the proposed approach, a variable-gain up-converter for 5-GHz wireless LAN applications has been fabricated with a low-cost 46-GHz-f_rceil silicon bipolar technology. The adopted VGA, operating at a frequency of 1 GHz, provides a linear-in-dB gain control characteristic over a 30-dB dynamic range with a 2-dB step and a +0.8-dB gain error.     

Granular flows down inclined channels with a strain-rate dependent friction coefficient. Part I: Non-cohesive materials

The flow of a granular material down an incline of finite width with a strain-rate dependent coefficient of friction and a conical yield criterion is semi-analytically obtained using a characteristic method for flows on a deep layer of grains. This analysis leads to a flow field with three distinct zones: a Bagnold-flow zone below the free surface, a dead-zone and a matching zone between the two, linked to slippage at the wall. A good agreement between the computed flow field and experimental data is obtained.     

Hierarchical-genetic-algorithm-based design of a large scale Fresnel lens for a reading light system with multiple LED sources

A conventional Fresnel lens is suitable to be used in the reading light system due to its features of directing and collecting light rays, as well as its properties of being essentially flat, plastic, lightweight, and cost efficient. However, it is not suitable for a reading light system with multiple light sources. To a reading light system with multiple light sources, a Fresnel lens with suitably designed groove angles can be used to improve the performance of that system in both illuminance and uniformity. Nevertheless, suitable groove angles are rather difficult to find if a Fresnel lens consists of a lot of groove angles and each angle covers a wide range of degrees. We develop a hierarchical genetic algorithm (HGA) to search for a set of optimal groove angles to design a Fresnel lens for a reading light system with multiple light sources from an enormous searching space. In addition, the groove angles of the Fresnel lens are directly derived from a conventional Fresnel lens database. The design goal is to maximize the illuminance and simultaneously maintain the uniformity of light rays incident to a specified reading surface. As a result, we can demonstrate that a HGA really works better than a genetic algorithm and the optimally designed Fresnel lens, indeed, offers a better light-guiding performance than a conventional Fresnel lens for a multiple-LED reading light system.     

Generally configured supply chain with flexible local control strategies

We consider a supply chain that comprises manufacturing stations, distribution stations and retail stations. A manufacturing station consists of a limited input buffer, a machine, a limited output buffer, a set of kanbans and a vehicle. A distribution or retail station consists of a limited storage buffer and a vehicle. A manufacturing station can choose any one of two mechanisms, buffer and kanban, to control its work-in-process, whereas that in a distribution or retail station is controlled only by a buffer mechanism. A vehicle can choose either a push or pull policy for transporting items from other stations to its own station. The supply chain is generally configured, which means that a vehicle can go to more than one station for transporting items rather than to a single upstream station. A manufacturing station can be controlled under a flexible strategy such as a push policy and buffer mechanism (push/buffer), or a push/kanban, or a pull/buffer or a pull/kanban, whereas a distribution or retail station can be under a push/buffer or a pull/buffer. Then, a global control strategy of the supply chain is formed by combining all local control styles. Such a supply chain is modelled as a queuing network. A decomposition approach is developed for major performance measures such as the throughput of each station and the work-in-process in each station. The efficiency of the decomposition approach is evaluated by comparing numerical experiments with simulations.     

Micromachined Vibratory Gyroscopes Controlled by a High-Order Bandpass Sigma-Delta Modulator

This work reports on the design of novel closed-loop control systems for the sense mode of a vibratory-rate gyroscope based on a high-order sigma-delta modulator (SigmaDeltaM). A low-pass and two distinctive bandpass topologies are derived, and their advantages discussed. So far, most closed-loop force-feedback control systems for these sensors were based on low-pass SigmaDeltaM's. Usually, the sensing element of a vibratory gyroscope is designed with a high quality factor Q to increase the sensitivity and, hence, can be treated as a mechanical resonator. Furthermore, the output characteristic of vibratory rate gyroscopes is narrowband amplitude-modulated signal. Therefore, a bandpass SigmaDeltaM is a more appropriate control strategy for a vibratory gyroscope than a low-pass SigmaDeltaM. Using a high-order bandpass SigmaDeltaM, the control system can adopt a much lower sampling frequency compared with a low-pass SigmaDeltaM while achieving a similar noise floor for a given oversampling ratio (OSR). In addition, a control system based on a high-order bandpass SigmaDeltaM is superior as it not only greatly shapes the quantization noise, but also alleviates tonal behavior, as is often seen in low-order SigmaDeltaM control systems, and has good immunities to fabrication tolerances and parameter mismatch. These properties are investigated in this study at system level