Multiobjective maintenance optimization of the continuously monitored deterioration system

With the development of the monitoring technology, it is more and more common that the system is continuously monitored. Therefore, the research on the maintenance optimization of the continuously monitored deterioration system is important. The deterioration process of the discussed system is described by a Gamma process. The predictive maintenance is considered to be imperfect and formulated. The expected interval of two continuous preventive maintenances is derived. Then, the maintenance optimization model of the continuously monitored deterioration system is presented. In the model, the minimization of the expected operational cost per unit time and the maximization of the system availability are the optimization objectives. The improved ideal point method with the normalized objective functions is employed to solve the proposed model. The validity and sensitivity of the proposed multiobjective maintenance optimization model are analyzed by a numerical example.       

Integrating dual-role variables in data envelopment analysis

Traditional data envelopment analysis (DEA) theory assumes that decision variables are regarded as inputs or outputs, and no variable can play the roles of both an input and an output at the same time. In fact, there exist some variables that work as inputs and outputs simultaneously and are called dual-role variables. Traditional DEA models cannot be used to appraise the performance of decision making units containing dual-role variables. The paper analyzes the structure and properties of the production systems comprising dual-role variables, and proposes a DEA model integrating dual-role variables. Finally the proposed model is illustrated to evaluate the efficiency of university departments.       

LLR calculation for LDPC coded SCBT in 60 GHz WPAN

The single-carrier block transmission (SCBT), a.k.a., single-carrier frequency-domain equalization (SC-FDE), is being considered as an option technique for the wireless personal area network (WPAN) operating at 60 GHz. It is found that for residential environment, in non-line-of-sight (NLOS) multi-path channels, the SCBT is much more effective to combat the inter-symbol interference (ISI) compared with orthogonal frequency division multiplexing (OFDM). Low-density parity-check (LDPC) codes are a class of linear block codes which provide near capacity performance on a large collection of data transmission and storage channels while simultaneously admitting implementable decoders. To facilitate using LDPC codes for SCBT system, a new log-likelihood ratio (LLR) calculation method is proposed based on pilot symbols (PS). Golay Sequences whose sum autocorrelation has a unique peak and zero sidelobe are used for creating the PS. The position and length of the PS are not fixed in the data blocks. The simulation results show that the proposed method can significantly improve the LDPC decoding performance in SCBT system. This is very promising to support ultra high-data-rate wireless transmission.     

Novel matched filtering method and its application

The method of using a narrowband filter to realize matched filtering is derived. A novel method of using spectrum sampling to realize matched filtering is presented, and the method can conquer the disadvantages that the narrowband filter cannot adopt the adaptive scheduling of phased array radars and realize matched filtering for several waveforms. A novel error extraction method is proposed, which uses a time division multipath method to realize the intermediate frequency extraction. This method can save lots of space for vehicle-born radar systems, reduce the influence of amplitude and phase distortion caused by devices, and enhance the system reliability. Simulation results show that the spectrum sampling method is applicable, and the implementation of frequency spectrum sampling is elaborated.     

Analysis and verification of network profile

The elements of network profile are proposed. Based   on the network traffic distribution model, the network profile includes   the application request rate, the branch transfer probability,   the ratio of application requests, and the probability distribution of   the requested objects. Based on the evaluation method of network   performance reliability, four simulation cases are constructed in   OPNET software, and the results show the four elements of profile   have impacts on the network reliability.     

Moving object detection in framework of compressive sampling

Compressive sensing is a revolutionary idea proposed recently to achieve much lower sampling rate for signals. In the image application with limited resources the camera data can be stored and processed in compressed form. An algorithm for moving object and region detection in video using a compressive sampling is developed. The algorithm estimates motion information of the moving object and regions in the video from the compressive measurements of the current image and background scene. The algorithm does not perform inverse compressive operation to obtain the actual pixels of the current image nor the estimated background. This leads to a computationally efficient method and a system compared with the existing motion estimation methods. The experimental results show that the sampling rate can reduce to 25% without sacrificing performance.     

Orthogonal genetic algorithm for solving quadratic bilevel programming problems

A quadratic bilevel programming problem is transformed  into a single level complementarity slackness problem by applying  Karush-Kuhn-Tucker (KKT) conditions. To cope with the complementarity  constraints, a binary encoding scheme is adopted for  KKT multipliers, and then the complementarity slackness problem  is simplified to successive quadratic programming problems,  which can be solved by many algorithms available. Based on 0−1  binary encoding, an orthogonal genetic algorithm, in which the orthogonal  experimental design with both two-level orthogonal array  and factor analysis is used as crossover operator, is proposed.  Numerical experiments on 10 benchmark examples show that the  orthogonal genetic algorithm can find global optimal solutions of  quadratic bilevel programming problems with high accuracy in a  small number of iterations.     

Velocity compensation methods for LPRF modulated frequency stepped-frequency（MFSF） radar

In the high speed target environment, there exists serious Doppler effect in the low pulse repetition frequency (LPRF) modulated frequency stepped frequency (MFSF) radar signal. The velocity range of the target is large and the velocity is high ambiguous, so the single method is difficult to satisfy the velocity measurement requirement. For this problem, a novel method is presented, it is a combination of cross-correlation inner frame velocity measurement and range-Doppler coupling velocity measurement. The cross-correlation inner frame method, overcoming the low Doppler tolerance of the cross-correlation between frames, can obtain the coarse velocity of the high speed target, and then the precision velocity can be obtained with the range-Doppler coupling method. The simulation results confirm the method is effective, and also it is well real-time and easy to the project application.     

基于T-S模糊模型的网络控制系统鲁棒H∝容错控制

针对同时存在网络时延和数据包丢失的网络环境,研究了执行器故障下一类非线性网络控制系统的鲁棒H_∞容错控制问题。基于不确定T-S模糊模型描述的非线性网络控制系统模型,考虑了更实际、更常见的执行器部分失效情况。通过引入一个积分不等式,获得了此类系统的时滞相关鲁棒稳定性条件,且采用锥补线性化算法给出了此类系统的鲁棒H_∞容错控制器设计方法。仿真算例表明,对于任意容许的不确定性以及执行器故障,所设计的控制器能使系统鲁棒渐近稳定,且具有H_∞范数界。       

Sensor fault-tolerant observer applied in satellite attitude control

The observing failure and feedback instability might happen when the partial sensors of a satellite attitude control sys- tem (SACS) go wrong. A fault diagnosis and isolation (FDI) method based on a fault observer is introduced to detect and isolate the fault sensor at first. Based on the FDI result, the object system state-space equation is transformed and divided into a corresponsive triangular canonical form to decouple the normal subsystem from the fault subsystem. And then the KX fault-tolerant observers of the system in different modes are designed and embedded into online monitoring. The outputs of all KX fault-tolerant observers are selected by the control switch process. That can make sense that the SACS is part-observed and in stable when the partial sensors break down. Simulation results demonstrate the effectiveness and superiority of the proposed method.     

Multiobjective fault detection and isolation for flexible air-breathing hypersonic vehicle

An application of the multiobjective fault detection and isolation (FDI) approach to an air-breathing hypersonic vehicle (HSV) longitudinal dynamics subject to disturbances is presented. Maintaining sustainable and safe flight of HSV is a challenging task due to its strong coupling effects, variable operating conditions and possible failures of system components. A common type of system faults for aircraft including HSV is the loss of effectiveness of its actuators and sensors. To detect and isolate multiple actuator/sensor failures, a faulty linear parameter-varying (LPV) model of HSV is derived by converting actuator/system component faults into equivalent sensor faults. Then a bank of LPV FDI observers is designed to track individual fault with minimum error and suppress the effects of disturbances and other fault signals. The simulation results based on the nonlinear flexible HSV model and a nominal LPV controller demonstrate the effectiveness of the fault estimation technique for HSV.     

“Unfolding” Natural Resource-Use Information Systems: Fieldwork in Botswana

My research examines the performance of natural resource-use information systems. I question why such systems, despite receiving substantial financial and human investment, appear to have a weak impact on projects, programs, and policy intended for rural poverty alleviation in developing countries. Drawing on my understanding of the process of unfolding introduced by C. West Churchman, and its particular relationship to Habermasian constitutive interests, I reflect on my experiences of using the concept during fieldwork undertaken in Botswana. The concept is found useful on two fronts: first, it provides a purposeful guide for gathering and processing information/knowledge—what I have termed an epistemological intent; second, it provides a useful template for evaluating other information systems; in particular, the role of expertise—what I have termed an ontological intent. The process of unfolding, as I understand it, also provides an invitation for constructive (rather than self-indulgent) personal reflection: what might be termed a constitutive reflexive intent. By making information gathering and knowledge generation less mystical and a more transparent social activity, the conceptual and practical application of the process of unfolding can help toward retrieving inquiry as being a purposeful, openly political, and thereby less deceptive engagement: features which I believe are found particularly wanting in the business of rural development information gathering.     

Why There's Nothing Wrong With Systems Thinking a Little Chaos Won't Fix? A Critique of Modern Systems Theory and the Practice of Organizational Change It Informs

We find ourselves at the dawning of a new millennium, uneasy denizens of a world of growing flux. The models of reality on which we rely in our continuing effort to master the turbulent and hypercompetitive marketplace are failing us. Even the much touted 20th-century innovation referred to by Peter Senge in his 1990 bestseller of the same name as the fifth discipline, that is, systems thinking, turns out to be less than adequate to the task. Therein lies the central purpose of this paper: to demonstrate why there's nothing wrong with systems thinking that a little chaos can't remedy. My intent is twofold: first, to expose the problematic partialness of this paradigm, given its tendency to direct one's focus to not to the whole system, but to its exterior half, and, second, to introduce the reader to Chaos, the powerful cosmology now emerging from 20th-century science, as a science of whole wholes—one that enables the practitioner of management and systems sciences to comprehend the system's externality, its subtle within, and most importantly, the crucial relationship between them.     

The Holistic Sense of Prison Phenomena in Venezuela. III. The Unity of the Research

In this paper the underlying systemic unity of the research reported in the two previous articles is sought. The research journey is examined in order to draw lessons concerning our systemic practice. In addition, an effort is made to relate Interpretive Systemology to some strands of systems, management and action research sciences. In so doing, we expect to draw some links that could be established between interpretive systemologists and the community of researchers who compose the select audience of SPAR.     

基于未知输入观测器方法的非线性切换系统故障检测

基于非线性未知输入观测器方法对一类离散时间非线性切换系统的故障检测问题进行了研究。给出了两种不同结构的非线性未知输入观测器。针对每一种观测器都考虑了两种切换信号:任意时间切换信号和满足平均驻留时间的切换信号。在任意切换信号下,使用了切换Lyapunov函数的方法来设计非线性未知输入观测器的参数;在满足平均驻留时间切换信号下,使用了多Lyapunov函数方法进行观测器参数的设计。然后利用已知的非线性未知输入观测器,得到残差生成器,进而实现故障检测。通过数值仿真例子,验证了故障检测方法的有效性。     

楼宇设备监测管理综合网络与智能故障诊断系统的研究

论述现代楼宇设备计算机远程监测与实时数据管理综合网络的系统结构,给出在线故障检测与离线故障诊断的实现方案,提出了这类系统故障诊断模糊专家系统的推理算法与时变隶属度的计算方法．采用实时监测与故障诊断专家系统有效地提高了楼宇设备的故障诊断分析能力、设备的运行效率以及物业管理水平.     

An Inquiry into the Historical Meaning of “The Fifth Discipline”

This paper shows a possible way to unfold the historical meaning of The Fifth Discipline. The thread of this way is the question about the new way to be human promoted by The Fifth Discipline. It is shown that this new way of being is not modern and coincides at several points with the ancient one. This situation is given two opposed interpretations. The first one points to a sort of a returning of our cultural worldview to the ancient one. A critique to this interpretation leads to a second possibility, which points to a radicalization of the instrumental trends of high modernity. Then a second critique is articulated which shows that the shift in the idea of humanity manifested by The Fifth Discipline remains obscure and problematic for our current way of thinking.     

基于观测器的非线性系统执行器死区故障的自适应跟踪控制

研究了一类具有不对称执行器死区故障的非线性系统的跟踪控制问题。基于扩张观测器,提出了一种新的自适应跟踪控制方法。取消了系统所有状态完全可测的限制。在死区模型所有参数以及系统非线性不确定项上界均未知的情况下,所设计的自适应控制器可以很好地消除执行器死区故障的影响,保证跟踪误差有界。仿真结果表明该方法的有效性。     

ON （∈, ∈ ∨q）-FUZZY FILTERS OF BL-ALGEBRAS

The authors introduce the notions of （∈, ∈ ∨q）-fuzzy Boolean （implicative, positive implicative, and fantastic） filters in BL-algebras, present some characterizations on these generalized fuzzy filters, and describe the relations among these generalized fuzzy filters. It is proved that an （∈, ∈ ∨q）fuzzy filter in a BL-algebra is Boolean （implicative） if and only if it is both positive implicative and fantastic.     

中央空调水系统传感器在线故障诊断研究

针对中央空调冷媒水系统中的温度传感器，本文提出了一种基于数理统计的在线故障诊断方法，以实现在线检测并修正传感器的突发漂移故障。首先建立控制体的能量守恒方程式，然后利用其残差值判断是否出现传感器漂移故障，根据残差方程的数字特征运用数理统计的方法建立诊断方程组，通过采集有效的系统运行数据求解诊断方程组以修正传感器的故障。该方法在已经建立的中央空调水系统仿真器上进行了验证，结果表明它能够较快地解决传感器突发漂移故障，将其嵌入到楼宇智能控制系统中将使系统更可靠，更智能。