Top PDF Fuzzy Threshold Values in the Robust Design of Controllers for Probabilistic Uncertain Systems

Fuzzy Threshold Values in the Robust Design of Controllers for Probabilistic Uncertain Systems

Fuzzy Threshold Values in the Robust Design of Controllers for Probabilistic Uncertain Systems

in a known structure. In conventional optimum control system design, uncertainties are not addressed and the optimization process is accomplished deterministically. In fact, it has been shown that optimization without considering uncertainty generally leads to non-optimal and potentially high risk solution [11]. Therefore, it is very desirable to find robust design whose performance variation in the presence of uncertainties is not high. Generally, there exist two approaches addressing the stochastic robustness issue, namely, robust design optimization (RDO) and reliability-based design optimization (RBDO), [12]. With the aid of ever increasing computational power, there have been a great amount of research activities in the field of robust analysis and design devoted to the use of Monte Carlo simulation [13]. In fact, Monte Carlo simulation (MCS) has also been used to verify the results of other methods in RDO or RBDO problems when sufficient number of sampling is adopted [14]. Monte Carlo simulation (MCS) is a direct and simple numerical method but can be computationally expensive. In this method, random samples are generated assuming pre-defined probabilistic distributions for uncertain parameters. The system is then simulated with each of these randomly generated samples and the percentage of cases produced in failure region defined by a limit state function approximately reflects the probability of failure.
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DESIGN OF ROBUST COMMAND TO LINE-OF-SIGHT GUIDANCE LAW: A FUZZY ADAPTIVE APPROACH

DESIGN OF ROBUST COMMAND TO LINE-OF-SIGHT GUIDANCE LAW: A FUZZY ADAPTIVE APPROACH

Intelligent techniques such as fuzzy control, neural network and the combination of fuzzy and adaptive controllers have been extensively applied to nonlinear systems. The self-organizing controllers, based on fuzzy logic or neural networks, are more flexible than conventional ones, due to the ability to choose the rule base , number of fuzzy rules, network structure and the number of neurons [9, 10]. Feedback linearization has been adopted before to control the LOS of a nonlinear missile [11], in which the angular momentum is assumed to be fixed relative to the axis of angular positions roll, pitch and yaw.
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Comput. Appl. Math.  vol.24 número1

Comput. Appl. Math. vol.24 número1

The main difficulties found in the control design for real systems are the nonlin- earities and uncertainties. If we treat nonlinearities as uncertainties the obtained results for stability are in general conservatives. In the last years, attractive sta- bility results for nonlinear systems using Takagi-Sugeno (T-S) fuzzy systems [1] based on the theory of stability of nonlinear systems appeared in Feng et al. [2] and Cao et al. [3]. In the same context, stability conditions using LMIs were given in Hong and Langari [4], Li et al. [5] and Wang et al. [6]. Following this trend, the robust stabilization of uncertain nonlinear systems became an ac- tive field of research wherein available robust control techniques for uncertain
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Universidade Federal de Minas Gerais Escola de Engenharia Programa de Pós-Graduação em Engenharia Elétrica Estabilização Robusta de Sistemas Não Lineares Incertos Utilizando Representações Algébricas Diferenciais

Universidade Federal de Minas Gerais Escola de Engenharia Programa de Pós-Graduação em Engenharia Elétrica Estabilização Robusta de Sistemas Não Lineares Incertos Utilizando Representações Algébricas Diferenciais

The class of uncertain nonlinear systems (1.1) can be recast by different representation and approximation techniques in order to enable LTI control design (see Figure 1.2). Applying these techniques depend on the type of mathematical model of the system. In the context of regional stability and DOA the aforementioned studies investigated different classes of nonlinear systems such as polynomial systems (Tibken, 2000, Hachicho and Tibken, 2002, Chesi, 2004b), non- polynomial systems (Chesi, 2009, Zeˇcevi´c and ˇSiljak, 2010, Ichihara, 2011), Takagi–Sugeno (T- S) Fuzzy Systems (Lee, 2013, Gering et al., 2015) and rational systems (El Ghaoui and Scorletti, 1996, Rohr et al., 2009, Coutinho et al., 2009, Coutinho and De Souza, 2013, Trofino and Dezuo, 2014). However, when the parametric uncertainties and nonlinearities are taken into account the conservatism of robust stability analysis and control synthesis of the nonlinear systems will rely on how the system is represented. This problem can be addressed while the system states and the uncertainties explicitly show up in the stability analysis instead of being considered as a norm-bounded input perturbation. Accordingly, among the aforementioned classes of nonlinear systems the rational systems, which covers polynomial systems as well, seems to be interesting for investigation since one is able to recast them in Linear Fractional Representation (LFR) and/or Differential Algebraic Representation (DAR) as will be discussed in detail in Chapter 2, Sections 2.2 and 2.3, specifically when the uncertainties are considered. The LFR and DAR representations of rational uncertain nonlinear systems were mostly used in the robust control community, that employs LMIs, as basic tools after it was shown that LMI-based robust stability
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A New Approach for Robust Design Optimization Based on the Concepts of Fuzzy Logic and Preference Function

A New Approach for Robust Design Optimization Based on the Concepts of Fuzzy Logic and Preference Function

In today’s world, systems should also be robust in the face of uncertainties. In other words, the performance of the optimal solutions must have fewer changes because of the variations of design variables and operational conditions. So a measure of robustness should be introduced during optimization and design (Gaspar-Cunha and Covas 2008). Taguchi introduces robust design at first to enhance product quality so that the quality is not sensitive to variations (Wan et al. 2011). The purpose of this method is to minimize the deviation of system response due to uncertainties. In classical design methods for considering uncertainty in a system design, the designers apply drastic tolerances and large safety factors (Jun et al. 2011). Assigning the values of these parameters is based on past experience of designer and has these drawbacks: a) specifying the values of safety factor for new systems and materials without any experience is difficult; b) in the design process, it is not easy to measure robustness and
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Evaluation of susceptibility of the ZRE1 alloy to hot cracking in conditions of forced strain

Evaluation of susceptibility of the ZRE1 alloy to hot cracking in conditions of forced strain

Typical temperatures for the process of crystallization and melting of the ZRE1 alloy, i.e. temperature of the beginning and the end of crystallization, and melting point for intermetallic phase and the Mg (α) solid solution were determined by differential thermal analysis (DTA). The tests were performed on the SETSYS thermal analyser manufactured by Setaram, using the TG-DTA head. The systems allows measurements of heat flow during phase changes related to melting and crystallization of tested alloys. The measurement of the temperature of the beginning and the end of the change were made with the method of two tangents’ intersection (“one set point”). The conditions of the experiment are given in table 2, and the DTA curves for the ZRE1 alloy during heating and cooling are shown in figure 2.
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Design And Implementation Of Smart Living Room Wireless Control For Safety Purpose

Design And Implementation Of Smart Living Room Wireless Control For Safety Purpose

Smart living room wireless control using android phone is described. The components required for smart living room are chosen. The overall circuits for the research are designed and constructed. How to implement the PIC programis described with flowchart. The developed PIC program and designed circuit are tested with Proteus software. The connection between Bluetooth and android apk is also tested. Any kind of android phone which consists of bluetooth can be used by installing smart living room apk. Since this smart living room system can be controlled by mobile, it becomes reliable and convenient to use for user. It can reduce the loss of energy.This system makes the user comfort and cost effective.It can provide high safety for the room.The proposed control system can be implemented to provide high standards of living by increasing the facilities of the living room.
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Criterion for selection the optimal physical and chemical properties of cobalt aluminate powder used in investment casting process

Criterion for selection the optimal physical and chemical properties of cobalt aluminate powder used in investment casting process

The quality of ceramic moulds and in consequence the quality of the castings depends on the thickness of the ceramic layer applied on the wax pattern. In turn, the thickness of the ceramic layer is a function of viscosity of the ceramic slurry. The decrease of pH value of ceramic slurry with colloidal silica results in higher viscosity and thickness of ceramic layer. It was established that pH value of cobalt aluminate should range from 8.5 to 10 [15]. Therefore, the measurements of pH value of cobalt aluminate water suspension and an alkaline elements contamination (sodium contamination) were performed. It was proved that modifiers manufactured by companies: Mason Color, Remet and Permedia Lublin have different pH value of aqueous suspension. The higher alkalinity characterizes the powders Mason Color - pH=9.93 and Remet – pH=9.42 companies (Table 3). The alkalinity of Permedia Lublin powder is lower and pH is 7.95 (Tab. 3). The results of sodium content investigations indicate that pH value of cobalt aluminate of aqueous suspension mostly depends on the sodium contamination C Na (Tab. 3).
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The Economics of Sub-optimal Policies for Traffic Congestion

The Economics of Sub-optimal Policies for Traffic Congestion

Confirming economic theory’s prediction, the aggregate results show that the urban toll is welfare superior to the rotation system. But a closer look at the welfare consequences of these policies reveal other things. First, despite generating a smaller welfare loss - on aggregate and on average - the urban toll affects more peolple than the rotation system. Second, the distribution of losses under the rotation system is even more skewed, meaning that there is a small group who gets an over proportional share of the policy’s burden. And third, the difference in the fraction of the population affected by both policies is due to the fact that wealthier citizes avoid the rotation by having a second car, or the “rotation’s day car”. This last result shows a side effect of the rotation system, that is to provide incentives for people to buy cars. It is an undesireable side effect.
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Mobility and Signal Strength- Aware Handover Decision in Mobile IPv6 based Wireless LAN

Mobility and Signal Strength- Aware Handover Decision in Mobile IPv6 based Wireless LAN

There are many studies, which have examined handover latency in Wireless Local Area Networks (WLAN). In the IEEE 802.11/b standard mode with WiFi, there are several signals that the MN must perform with the AP to obtain association in order to be able to send and receive forwarded traffic. This process contains sequence phases, like probe requests and probe responses, authentication requests and authentication responses, and finally, reassociation requests and reassociation responses. These sequences are distributed as three Layer2 phases: potential phase, probe or scanning phase, and authentication phase. In the potential phase, a MN senses if the current link quality is weakening when some frames fail to be transferred via the network. At the same time, a MN receives other signals, which belong to other, better quality APs in the range. While in the probe or scanning phase, a MN starts to collect the RSSI values for the APs that are available in the range and then makes decisions about the handover. The handover decision depends on the RSSI value, which determines the quality of the current link and the desirable link. Afterwards, the authentication phase is applied between the MN and the new AP; this happens when the authentication is enabled in the APs. In each active scan executed by the MN, the worst possible delay is 300-400 ms [6]. This delay period is taken every time the MN needs to obtain a list of APs in the range in order to make the handover decision.
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SINTONIA DE CONTROLADOR FUZZY POR ALGORITMO GENÉTICO EM SISTEMA DE NÍVEL DE LÍQUIDOS JOSÉ FLÁVIO BARBOSA DE ANDRADE

SINTONIA DE CONTROLADOR FUZZY POR ALGORITMO GENÉTICO EM SISTEMA DE NÍVEL DE LÍQUIDOS JOSÉ FLÁVIO BARBOSA DE ANDRADE

A configuração de um algoritmo genético é uma etapa critica para obtenção de bons resultados. Apesar disso, ainda não foi encontrado uma metodologia para a determinação ótima desse conjunto de parâmetros sendo que, uma determinada configuração pode ter um desempenho melhor que outra em um problema específico (BRAGA et al., 2000). As metodologias adotadas para a definição desses parâmetros normalmente são empíricas, isto é, baseadas na experiência prévia do projetista. A base de conhecimento utilizada neste sistema fuzzy poderia ser perfeitamente obtida diretamente de um projetista experiente, ou de forma analítica dos dados e sinais, ou automaticamente, através de algoritmo genético, como demonstra esse trabalho.
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Combination of Neural Networks and Fuzzy Clustering Algorithm to Evalution Training Simulation-Based Training

Combination of Neural Networks and Fuzzy Clustering Algorithm to Evalution Training Simulation-Based Training

Abstract —With the advancement of computer technology, computer simulation in the field of education are more realistic and more effective. The definition of simulation is to create a virtual environment that accurately and real experiences to improve the individual. So Simulation Based Training is the ability to improve, replace, create or manage a real experience and training in a virtual mode. Simulation Based Training also provides large amounts of information to learn, so use data mining techniques to process information in the case of education can be very useful. So here we used data mining to examine the impact of simulation-based training. The database created in cooperation with relevant institutions, including 17 features. To study the effect of selected features, LDA method and Pearson's correlation coefficient was used along with genetic algorithm. Then we use fuzzy clustering to produce fuzzy system and improved it using Neural Networks. The results showed that the proposed method with reduced dimensions have 3% better than other methods.
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Braz. J. Chem. Eng.  vol.27 número3

Braz. J. Chem. Eng. vol.27 número3

Before discussing more details of the procedure, it is worthwhile to note certain aspects of dependability. A different interpretation of it can be given by the percentage of time when the plant is operating in specification (Freeman and Gaddy, 1975). In many cases, D 1 < does not necessitate that, on average, the process will not be able to meet the specification, for which it has been designed. On the contrary, in certain cases, a plant with a smaller additional design margin may still be able to make up for times of reduced production when the varying parameters are in its advantage at a later time. Also, D < does not entail 1 that the plant is down at some instances throughout the year, though product quality or quantity may be reduced. In contrast, methods requiring the process to stay within its specifications at all times (e.g., Grossmann et al., 1983) lead to greater equipment overdesign to fulfill these conditions. This is more important when the uncertainty stems from parameters that continue to vary when the process is operational, such as feedstock purity conditions. In contrast to uncertainties in, e.g., kinetic constants whose value is unknown, but actually does not vary, it is not necessary to design processes that are always capable of delivering nominal capacity.
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Functionalities of multi-agent systems in Programmable Logic Controllers

Functionalities of multi-agent systems in Programmable Logic Controllers

EAS are the integrated systems with equipment that allow modularity, adaptability and scalability of the product. They are modules who should provide open hardware and software architecture with plug and play functionality; the connection is made without the other equipment being disconnected or reconfigured. The reconfiguration of systems allows the manufacture to be evolvable (PEIXOTO; PEREIRA; CAVALCANTE, 2012). The mounting system of the evolution is based on simple systems, reconfigurable elements with specific tasks (system modules), which allow a continuous evolution of the system. An EAS can co-evolve with the product and assembly process (Ribeiro, 2012). The EAS can be implemented by Service Oriented Systems (SOA), that is the basic element in the abstraction of services which has properties of autonomy, interoperability, platform independence, encapsulation and availability ( LEITÃO; Et al. , 2001), (LEITÃO, 2009), or by using Multi-agent Systems (MAS) defined as a paradigm derived from the distributed artificial intelligence field, characterized by decentralization and parallel execution of activities based on autonomous entities, called agents (Oliveira, 2004).
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The Existence Of Leading Islands Securing And The Border Areas Unitary State Of Indonesia An Analysis In Law Perspective

The Existence Of Leading Islands Securing And The Border Areas Unitary State Of Indonesia An Analysis In Law Perspective

www.ijstr.org can support the management of coastal areas, so it can be arranged on the setting, management, utilization, preservation and protection and security of marine areas and determination of Indonesia‘s borders area. To be comprehend the existence of territory of a country that called as maritime country in which it consists of securing a territorial waters, leading islands and natural resources outcomes such as fishing become rights and obligations of all government and relevant agencies to handle the management of coastal areas and leading small islands of various foreign ships or parties that violate a cross-border waters the other party‘s interests that can threaten the state‘s sovereignty.
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Resear ch Ar ticle

Resear ch Ar ticle

Table 3 presents the estimates of pertinence through the fuzzy controller based on the Annicchiari- co method (1992), which indicate in which of the four groups each of the genotypes was to be classified by the fuzzy controller. Thus, the BRS Pontal cultivar was classified as general behavior (GB). This classification is correct, since this genotype presented high index of recommendation readings both for favorable environ- ments (ω f ) and highly unfavorable (ω d ).The cultivars BRS Estilo, Campeão 2 and IPR Juriti were classified as indicated for favorable environments (FE). This is due to the recommendation index for favorable environ- ments being (ω f ) High (average yield above the general average, which is 1,952 kg ha –1 in favorable environ-
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Irrigation controller mechanically actuated by soil-water tension: II - Field evaluations

Irrigation controller mechanically actuated by soil-water tension: II - Field evaluations

In this study, a field evaluation of the performance of an irrigation controller mechanically actuated by soil-water tension (SWT) was performed. The controller employs a tensiometer used as a sensor of SWT to directly control a mechanically actuated hydraulic valve. Six controllers were installed in an orchard to control the irrigation for six rows of plants over 64 days. Each controller controlled the irrigation of one lateral drip line. The drip irrigation system was gravity-fed from a water source placed 7 m above the soil surface. The SWT and the pressure in each lateral line were measured to evaluate the performance of the controllers. All the controllers tested in the field autonomously initiated and terminated the irrigation during the evaluation. Irrigation events were initiated when values close to the set soil-tension values were reached and were terminated at lower soil-tension values. As the SWT in the root zone was maintained close to the setup threshold plus 20% tolerance for at least 90% of the evaluation period, the performance of the controllers was considered satisfactory. The proposed controller was shown to be functional and was operated effectively for an SWT range of up to 30 kPa, which is commonly encountered under high-frequency irrigation conditions.
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An Analysis Of The Difference In Gender Level Of Cassava Production And Access To Land In Abia State Nigeria

An Analysis Of The Difference In Gender Level Of Cassava Production And Access To Land In Abia State Nigeria

Women also provide most of the labour for harvesting and post-harvest activities (FAO, 1996). Cassava is important, not only as a food crop but even more as a major source of income for rural households (Davies et al., 2008). As a cash crop, cassava generates cash income for the largest number of households in comparison with other staples. However the sustainability of this staple crop depends on the enormous availability of land for its cultivation. Land is the foundation of all human, social and economic activities that lie at the heart of social, political, or economic life of most nations especially African nations. Land is recognized as a primary source of wealth, social status and power, the basis for shelter, food, and economic activities and significantly provides employment opportunities in the rural areas. Land is fundamental to agriculture, yet the different challenges women face in accessing them are rarely fully addressed. For women, it is often particularly difficult to access, own or control land due to legal or cultural restrictions ( Emeasoba, 2012). This problem is widespread; women hold title to approximately two percent of land globally and are frequently denied the right to inherit property (World Bank, 2005). The wealth obtainable from cassava production, processing and marketing as a result of gender inequality remains under serious threat if nothing is done to improve the operating environmental and socio- economic conditions of the farmers in terms of asset holding, welfare and credit availability. The broad objective of the study is to analyze male and female access to land for cassava production in Abia state and specifically to describe the socio-economic characteristics of the respondents and the difference in quantity of cassava produced by both male and female respondents.
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Assessment Of NPK In Human Male And Female Urine For Its Fertilising Potential In Agriculture

Assessment Of NPK In Human Male And Female Urine For Its Fertilising Potential In Agriculture

discharge into water is reduced by about 60% irrespective of the type of treatment [10]. Pure urine is sterile but there is the likelihood of cross-contamination with the use of urine separating (Ecosan) toilets [28]. According to Jönsson et al. (2000) separated urine contains a greater part of the total nutrients in normal sewage; 80% of N, 55% of P, and 60% of K in just 1.5% of the volume of the sewage. According to Rheiberger (1936), there are comparable levels of creatine, urea and ammonia nitrogens in urine among primates such as man, mangabeys, baboons and chimpanzees. However, he identified sex differences in creatinine nitrogen coefficients of the male mangabeys, baboons and chimpanzees to be higher than those in the female counterparts. In small cases there was reversal of the magnitude seen in the macaques species precluding an assumption as to the validity of the observation. In analysing sex differences in urine with respect to lysine and α - amino nitrogen, the mean excretion of α - amino nitrogen whether ―total,‖ ―free,‖ or ―bound,‖ was higher for females than for males [22]. Thus, it is possible that the higher rate of amino acid excretion observed in females might be correlated with the sexual cycle, although no evidence of this was observed in the case of the four amino acids studied by Thompson and Kirby (1949) when samples from the same subjects were taken at various stages of the menstrual cycle. The influence of sex (gender) on the level of NPK in human urine has received no attention. Therefore, there is a need to study the effect from the Ecological Sanitation (ECOSAN) perspective, especially under local conditions. This is because gender ECOSAN urinals are going to spring up with the advent of industries and ECOSAN concepts, especially in the developing countries. The use of urine in agriculture has been studied in countries such as Sweden, Germany, Switzerland, South Africa, Burkina Faso and Nigeria. In all these studies, the fertilizing ability of human urine was established as being comparable to that of chemical fertilizers, such as 21% N ammonia. However, in Ghana little U
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Design of a Single Input Fuzzy Logic Controller Based SVC for Dynamic Performance Enhancement of Power Systems

Design of a Single Input Fuzzy Logic Controller Based SVC for Dynamic Performance Enhancement of Power Systems

Wang . Y et al. [3] discussed voltage stability enhancement by a non-linear SVC controller designed through direct feedback linearisation technique. Gracia kasuki et al. [4] had shown the application of SVC to damp out sustained voltage oscillations for a given level of reactive power demand as well as increasing the maximum point of system’s loadability using a first order delay model of SVC. Mohamed S. Sad et al [5] introduced washout aided feedback in the design of SVC to increase the range of stable operation of a power system susceptible to voltage collapse.
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