Fuzzy control of arrivals to tandem queues with two stations

We consider two queues in tandem, each of which has its own input of arriving customers, which, in turn, may either be accepted or rejected. Suppose that the system receives a fixed reward for each accepted customer and pays a holding cost per customer per unit time in the system. The objective is to dynamically determine the optimal admission policies based on the state of the system so as to maximize the average profit (reward minus cost) over an infinite horizon. This model finds applications in flow control in communication systems, industrial job shops, and traffic-flow systems. In this paper, a novel approach is presented using fuzzy control. This approach explicitly finds the optimal policy, which up until now has defied analytical solutions     

Solving equations by hybrid evolutionary computation techniques

Evolutionary computation techniques have mostly been used to solve various optimization and learning problems. This paper describes a novel application of evolutionary computation techniques to equation solving. Several combinations of evolutionary computation techniques and classical numerical methods are proposed to solve linear and partial differential equations. The hybrid algorithms have been compared with the well-known classical numerical methods. The experimental results show that the proposed hybrid algorithms outperform the classical numerical methods significantly in terms of effectiveness and efficiency     

Segmentation method for face detection in complex background

A new method for segmenting candidate regions of human faces with a complex background is proposed. A number of evolutionary agents are distributed in the 2D colour image environment in order to find the face-like pixels and locate each face-like region. Experimental results show that the proposed method is fast and robust     

Optimisation of two-step sintering parameters to produce bioactive and dense zirconia-hydroxyapatite composite ceramics

3Y-TZP along with Hydroxyapatite (HAp) are common bioceramics used in bone tissue engineering scaffolds to yield better patient outcomes and faster healing times. However, significant differences in thermal expansion of these ceramics result in challenges to co-sintering these materials without losing functionality and strength. In this work, a two-step sintering (TSS) process was utilised to co-sinter composites using (1-x)3Y-TZP and xHAp where x varies between 20 and 80 wt%. A peak temperature of 1300 °C, a plateau temperature of 1175 °C, a holding time of 600 min and heating rate of 10 °C/min were the optimum TSS conditions for all compositions. The TSS process produced specimens with grain sizes between 0.5 and 1.2 µm and a compression strength between 88 and 176 MPa. The similarity in compression strength of these zirconia-hydroxyapatite composites with natural bone and the retention of HAp make them suitable for bone tissue engineering applications in load bearing areas.     

Multi-factor impact mechanism on combustion efficiency of a hydrogen-fueled micro-cylindrical combustor

As it is important to achieve higher combustion efficiency for applications of micro-cylindrical combustor, the multi-factor impact mechanism on the combustion efficiency of a hydrogen-fuelled micro-cylindrical combustor is investigated in this work. Firstly, six factors such as hydrogen/air equivalence ratio, inlet velocity, inlet temperature, wall thermal conductivity, wall emissivity and convective heat transfer coefficient of outer wall and five levels of each factor are determined. Orthogonal design table L₂₅(5⁶) is introduced to arrange cases. Secondly, grey relational analysis is adopted to investigate the effects of the six factors on combustion efficiency. Finally, the results of grey relational analysis are validated by analysis of variance. Based on grey relational analysis and analysis of variance, it is determined that the impact ranking from the largest to the smallest is hydrogen/air equivalence ratio, inlet velocity and inlet temperature, followed by the other three factors. The impact of wall thermal conductivity, convective heat transfer coefficient of outer wall and wall emissivity is considered to be equal due to their difference of impact on combustion efficiency is very small. This work provides us significant reference for optimizing combustion efficiency of a hydrogen-fuelled micro-cylindrical combustor.     

高强墩头式预应力钢拉杆及工程应用

笔者介绍了成都庶民科技有限公司所生产的四种型号的新型钢结构构件一新型墩头式钢拉杆，并通过与我国现行相关规范和市场应用现状对其材料性能、经济性能进行分析。结果表明，成都庶民科技有限公司所生产的新型墩头式钢拉杆材料性能符合我国现行相关规范，在实际轻钢结构应用中，其拥有节约钢材，便于安装，缩短工期等方面优点，经济性能优于普通圆钢支撑，在今后的工业实践中更广泛的应用。     

Comments on "The multisynapse neural network and its application to fuzzy Clustering"

In the above-mentioned paper, Wei and Fahn proposed a neural architecture, the multisynapse neural network, to solve constrained optimization problems including high-order, logarithmic, and sinusoidal forms, etc. As one of its main applications, a fuzzy bidirectional associative clustering network (FBACN) was proposed for fuzzy-partition clustering according to the objective-functional method. The connection between the objective-functional-based fuzzy c-partition algorithms and FBACN is the Lagrange multiplier approach. Unfortunately, the Lagrange multiplier approach was incorrectly applied so that FBACN does not equivalently minimize its corresponding constrained objective-function. Additionally, Wei and Fahn adopted traditional definition of fuzzy c-partition, which is not satisfied by FBACN. Therefore, FBACN can not solve constrained optimization problems, either.     

A qualitative model of cross-lane inhomogeneities in traffic flow

The dilemma of traditionally quantitative methods in application to complex systems leads more and more researchers to emphasize the qualitative methods that can tackle the qualitative knowledge. Based on the concepts and ideas of qualitative reasoning, a preliminary qualitative method for modeling the traffic flow is proposed in this paper. Following new concepts, such as the homogenous measure index, which can be treated as an entropy to judge the homogeneity of traffic flow, a set of linear parameters-varying difference equations is used to describe the process of qualitative state transitions of the traffic flow. The procedures as well as the rationality of qualitative modeling for the traffic flow are illustrated by the data obtained from an actual traffic system-the Beijing Third Ring Road. Comparing the simulation results with actual data, it is proven that the results obtained by the proposed qualitative model coincide with the actual situation and the qualitative model can basically depict the nonhomogenous state transitions of traffic flow.     

Optimal design of multistage discrete Raman amplifiers incorporating midway isolators

Multistage discrete Raman amplifiers with midway isolators to suppress double Rayleigh backscattering are fully investigated at constant nonlinearity. The results show that placing Raman pumps at the last stage only is sufficient. For most conditions, two isolators can achieve adequate performance improvement, while more isolators only lead to slightly optical signal-to-noise ratio increase. The optimum positions of the isolators are insensitive to varied Raman gains, nonlinear phase shifts, and Rayleigh coefficients, but sensitive to different fiber lengths as well as Raman pumping schemes. Moreover, backward-pumping schemes can derive better noise performance than bidirectional pumping when using midway isolators.     

无线传感器网络的信任模型研究

无线传感器网络环境下的信任模型作为密码技术的有效补充,在抵抗内部攻击、识别故障节点等方面发挥着重要作用,可应用于安全路由、安全数据融合等,用以提高系统的安全性、可靠性和公平性;分析了无线传感器网络环境下信任模型的特性,详细介绍了信任模型的评价指标;选取4种典型的信任模型进行评述,分析其优势和不足,并根据各项评价指标进行比较;最后指出目前研究中存在的问题,并展望了进行后续研究的切入点。