Determination Of The Phase Current Waveform For A Disc‐Type Axial‐Flux Wheel Motor

An optimal design of the driving current pattern for a disc‐type axial‐flux brushless DC wheel motor of an electric vehicle is proposed in this paper. The electro‐magnetic dynamic model of the motor is established with magnetic circuits, describing the relationship between the output torque and excitation current. The optimal current pattern, in terms of magnitude and phase angle, is then obtained by maximizing the output torque with respect to the rotor shift. Compared with the traditional three‐phase‐on current pattern of fixed 120–degree phase shift, both the average torque and efficiency with the driving current of an optimal advanced switching angle are seen to be improved under various loading conditions. The motor performance with the optimal driving waveform is simulated and verified by experiments.     

Incremental Value Iteration for Time-Aggregated Markov-Decision Processes

A value iteration algorithm for time-aggregated Markov-decision processes (MDPs) is developed to solve problems with large state spaces. The algorithm is based on a novel approach which solves a time aggregated MDP by incrementally solving a set of standard MDPs. Therefore, the algorithm converges under the same assumption as standard value iteration. Such assumption is much weaker than that required by the existing time aggregated value iteration algorithm. The algorithms developed in this paper are also applicable to MDPs with fractional costs.     

基于模函数与像素值差值的高质量双图像可逆信息隐藏

为解决在一些一对二的交流场景中使用信息隐藏技术来传递信息时对载密图像的视觉质量和载体图像的精确度的高要求问题. 在本文中提出了一种基于模函数和像素值差值(pixel value difference , PVD)的双图像可逆信息隐藏方案, 通过模函数和对数函数确定了PVD范围表, 从而确定在单位面积上的信息嵌入位数以及模函数的系数. 所提出的方案可以在信息嵌入位数不断增加的情况下仍然保持像素值的修改量与信息嵌入位数之比不大于0.5, 所以与目前一些基于PVD的方案相比在像素对差值越大的图像中越占有优势. 实验结果表明与现有的一些在载密图像质量方面优质的方案相比, 具有更高的PSNR和SSIM, 此外本方案在抗RS隐写分析和PDH隐写分析的静态攻击方面上具有良好的性能, 并且避免了大多数在基于像素值差值的信息隐藏方案中对溢出问题的解决方案复杂繁琐的情况.     

Structural topology optimization using ant colony optimization algorithm

The ant colony optimization (ACO) algorithm, a relatively recent bio-inspired approach to solve combinatorial optimization problems mimicking the behavior of real ant colonies, is applied to problems of continuum structural topology design. An overview of the ACO algorithm is first described. A discretized topology design representation and the method for mapping ant's trail into this representation are then detailed. Subsequently, a modified ACO algorithm with elitist ants, niche strategy and memory of multiple colonies is illustrated. Several well-studied examples from structural topology optimization problems of minimum weight and minimum compliance are used to demonstrate its efficiency and versatility. The results indicate the effectiveness of the proposed algorithm and its ability to find families of multi-modal optimal design.     

An innovative framework of collaborative-based workflow in Development Chain Management

Currently, most product development procedures have been characterized as unnecessarily complicated. To maintain a competitive edge and to simplify the procedures, joint efforts from different functional groups play such crucial role. Specifically, information from marketing, sales, engineering, sourcing, and manufacturing should be cross-referenced. In addition, adopting pre-defined workflows contributes to efficient collection of distributed information. Moreover, unlike traditional workflow, a collaborative-based workflow (CWF) in product development process boasts of complicated workflow forms with manifold views for a workflow execution. Traditional workflow solutions, for instance, can only transmit a workflow form through different actors. Such workflow solutions merely offer modeling approval-based workflow (AWF), such as drawing reviews or absence applications.     

Effects of impurities on removal of polysilicon in chemical-mechanical polish

The effects of impurities on the removal of doped polysilicon in the chemical-mechanical polishing (CMP) process is discussed. It has been found that the Si-CMP is seriously retarded in the presence of boron impurities. In this paper, effects of several usually used n-and p-type impurities for polysilicon are investigated. Successive polishing was performed to reveal the correlation between the removal rate and the dopant concentration along the depth of polysilicon layer. The removal is seriously retarded for p-type samples and slightly enhanced for n-type samples. After excluding the interference from surface roughness, linear relationship was found between the resultant removal rate and the doping concentration. In this study, electrostatic interaction between the reactant ions and the ionized impurities at the silicon surface is proposed to be the primary factor to change the removal reaction rates. For p-type polysilicon etched in an alkaline aqueous solution, transport of OH⁻ anions is hindered because OH⁻ anions experience a repelling force in front of the negative-charged acceptors. Following the same principle, the removal reaction forn-type polysilicon is enhanced. However, the removal rate forn-type polysilicon is rather limited by surface reaction than by transport of reactant ions. As a consequence, the enhancement of removing n-type polysilicon is not so prominent as compated to the retardation effect found for removal of p-type polysilicon.     

Payment versus bid cost [The Business Scene]

This article summarizes the recent developments in the solution methodology of payment-cost minimization and the economic analysis of the two auction methods. Topics such as revenue adequacy implications are brought into discussion. Generally speaking, the research on the appraisal of the two auction methods is still at the early stages, and that a comprehensive study of the two auction methods is highly valuable for both researchers and industrial practitioners. This article can initiate more serious debate among researchers and stakeholders as to which objective should be used in ISO markets.     

Effect of sweetener types on chemical and sensory quality of frozen kiwifruit concentrates

Fresh, mature kiwifruits, not suitable for the fresh market, were used to prepare frozen kiwifruit concentrate. Sucrose, 62 DE corn syrup and high-fructose Cornsweet₅₅ were used either alone or in various combinations on the same dry basis to prepare six sweetener types.The acidity, soluble solids, and ascorbic acid content of the fresh kiwifruit pulp and concentrates are presented. The high performance liquid chromatography method (HPLC) was used to quantitatively analyse the oligosaccharides present in the concentrates. Colour measurements made with a Hunter colour difference meter indicated that the kiwifruit concentrates differed in colour attributes, depending on the holding temperature. Objective measurements with a Brookfield viscometer indicated that the consistency of the concentrates varied with the sweetener types. The concentrate made with 62 DE corn syrup and sucrose (1:2) was thickest in consistency.Kiwifruit nectars prepared from frozen concentrates sweetened with either sucrose alone or Cornsweet₅₅ alone were preferred by the taste panel to the others.