A fuzzy DEA model with undesirable fuzzy outputs and its application to the banking sector in India

Data envelopment analysis (DEA) is a widely used technique for measuring the relative efficiencies of decision making units (DMUs) with multiple inputs and multiple outputs. However, in real life applications, undesirable outputs may be present in the production process which needs to be minimized. The present study endeavors to propose a DEA model with undesirable outputs and further to extend it in fuzzy environment in view of the fact that input/output data are not always available in exact form in real life problems. We propose a fuzzy DEA model with undesirable fuzzy outputs which can be solved as crisp linear program for each α in (0, 1] using α-cut approach. Further, cross-efficiency technique is applied to increase the discrimination power of the proposed models and to rank the efficient DMUs at every α in (0, 1]. Moreover, for better understanding of the proposed methodology, we present a numerical illustration followed by an application to the banking sector in India. This is the first study which attempts to measure the performance of public sector banks (PuSBs) in India using fuzzy input/output data for the period 2009–2011. The results obtained from the proposed methodology not only depict the impact of undesirable output on the performance of PuSBs but also analyze efficiently the influence of the presence of uncertainty in the data over the efficiency results. The findings show that the efficiency results of many PuSBs vary with the variation in α during the selected period.     

多路输出反激式开关电源的改进与实现

针对传统开关电源存在的控制芯片供电方式耗能较大、反馈电路光耦有效输入电流范围窄两个问题,对传统电源电路进行了改进,设计并实现了一款性能优良的48V转+5V、±15V,输出功率25W的三路输出反激式开关电源。样机输出电压精度为0.2%(+5V)、0.53%(+15V)、0.6%(-15V),输出电压纹波为20mV(+5V)、50mV(+15V)、60mV(-15V),电压精度和纹波率均满足小于1%的要求;测试表明:该电源性能优良,具有效率高,稳压精度高,负载调整率高等优点,有很高的生产应用价值。     

基于双闭环控制的单端反激式多路隔离输出开关电源的实现

以UC3842电流型控制芯片为核心,以MOSFET IRFPG40作为功率开关器件,设计及研制了一种单端反激式、双闭环电流控制、5路稳定电压输出的40W开关稳压电源,用作于变频器逆变侧IPM模块的专用驱动电源以及其他外围电路工作电源,实验证明所设计的开关电源具有高稳定性。     

Performance of the most common non‐cryptographic hash functions

Non‐cryptographic hash functions (NCHFs) have an immense number of applications, ranging from compilers and databases to videogames and computer networks. Some of the most important NCHF have been used by major corporations in commercial products. This practical success demonstrates the ability of hashing systems to provide extremely efficient searches over unsorted sets. However, very little research has been devoted to the experimental evaluation of these functions. Therefore, we evaluated the most widely used NCHF using four criteria as follows: collision resistance, distribution of outputs, avalanche effect, and speed. We identified their strengths and weaknesses and found significant flaws in some cases. We also discuss our conclusions regarding general hashing considerations such as selection of the compression map. Our results should assist practitioners and engineers in making more informed choices regarding which function to use for a particular problem. Copyright © 2013 John Wiley & Sons, Ltd.     

基于MOCCCII-C的n阶电流模式滤波器

提出了一种基于多输出电流控制电流传输器的通用高阶电流模式滤波器的系统综合设计方法,该方法通过对n阶通用电流模式滤波器的传递函数进行数学分析,将其分解为n个无损积分器级联的形式,由此提出的电路结构简单,仅由n个有源器件,n个接地电容构成。并只要通过改变输入电流的接入方式和接入数目就可以实现不同的滤波功能,便于集成,面向实际电路完成P sp ice仿真。     

任意阶电流模式椭圆滤波器的综合设计

通过对任意奇数阶电流模式滤波器传递函数进行数学分析,将其分解为n个无损积分器级联的形式,并根据椭圆型滤波器的传输函数对输出电流信号进行线性组合,从而提出了一种奇数阶的电流模式椭圆滤波器的系统综合法。由该方法实现的电路结构简单,仅由（3n-1）／2个有源器件,n个接地电容构成。面向实际电路完成Pspice仿真,结果表明由该方法产生的滤波器具有良好的性能。     

一种新的多目标角跟踪方法

该文提出了一种新的多目标角跟踪算法。首先利用高分辨处理估计出目标的个数及其初始角度,接着通过对协方差矩阵的更新得到不同时刻各个目标的角度。该算法减小了阵元噪声的影响,相邻时刻估计得到的角度之间是自动关联的,省去了运算量较大的数据关联过程。此外,文中还提出了进一步提高性能的两种方法：通过引入预测值减小了算法中两个近似带来的误差;采用记忆跟踪法来处理有目标交汇的情况。仿真结果表明,该算法有较高的跟踪性能。     

EFFECTIVE DECENTRALIZED TITO PROCESS IDENTIFICATION FROM CLOSED‐LOOP STEP RESPONSES

In this paper, a new identification method performed in the time domain based on the decentralized step‐test is proposed for two inputs and two outputs (TITO) processes with significant interactions. In terms of parameter identification, the coupled closed‐loop TITO system is decoupled to obtain four individual single open‐loop systems with the same input signal. As in the SISO case, new linear regression equations are derived, from which the parameters of a first‐ or second‐order plus dead‐time model can be obtained directly. The proposed method outperforms the existing estimation methods for multivariable control systems that use step‐test responses. Furthermore, the method is robust in the presence of high levels of measurement noise. Simulation examples are given to show both effectiveness and practicality of the identification method for a wide range of multivariable processes. The usefulness of the identified method in multivariable process modeling and controller design is demonstrated.     

Fault detection and isolation design for uncertain nonlinear systems based on full-order,reduced-order and high-order high-gain sliding-mode observers

This paper considers the observer-based fault detection and isolation design problems when the observer matching condition is not satisfied. Based on the relative degree concept, an auxiliary output vector that may satisfy the observer matching condition is constructed. Since the auxiliary output vector contains unknown information, we use a high-order high-gain sliding-mode observer to exactly estimate not only the auxiliary outputs, but also their derivatives in a finite time. Then, an adaptive robust full-order observer is developed to serve as an actuator fault detection observer. For the actuator fault reconstruction purpose, a reduced-order observer is proposed to estimate the system states even if there are some actuator faults and an actuator fault reconstruction method is provided to reach the fault isolation purpose. A numerical simulation example is used to illustrate the effectiveness of the proposed methods.