With the continued development of economy, the energy demand increases continually . The industry is interested in evaluating the technology of heat pump, with applications mostly for water heater. This thesis analyzes and compares the heating efficiency of electric heater, gas heater and heat pump heater . A fuzzy theory is employed to the developed heating algorithm to raise the efficiency of the heat pump heater and suppress the unnecessary heating at the high temperature. According to the experiment, the heat pump heater could reach 60% energy saving while gas heater could attain 23% in comparison with the electric heater under the same temperature, The system could work all year around and can provide users with water at a proper temperature. In the winter, COP of heat pump heater could reache 2.1~2.5 while in the summer around 2.61~2.95. The energy saving is obvious.

Thesis (Ph. D.) in Physics--University of Maine, 2003. / Includes vita. Includes bibliographical references (leaves 129-143).

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: LabVIEW; fuzzy logic control; anesthesia. Includes bibliographical references (p. 71-74).

We are living in a world full of uncertainty and ambiguity. We usually ask ourselves questions that we are uncertain about their answers. Is it going to rain tomorrow? What will be the exchange rate of euro next month? Why, where and how should I invest? Type-1 Fuzzy sets are characterized by the membership function whose value for a given element x is said to be the grade of membership having a value in the interval [0, 1]. In addition, type-1 fuzzy sets have limited capabilities to deal with uncertainty. In our thesis, we study another concept of a fuzzy description of uncertainty which is called Type-2 fuzzy sets. According to this concept, for any given element x, we can’t speak of an unambiguously specified value of the membership function. Moreover, Type-2 fuzzy sets constitute a powerful tool for handling uncertainty. The aim of our thesis is to examine the potential of the Type-2 fuzzy sets especially in decision making. So, we present basic definitions concerning Type-2 fuzzy sets, and operations on these sets are to be discussed too. Then, Type-2 fuzzy relations and methods of transformation of Type-2 fuzzy sets will be introduced. Also, the theory of Type-2 Fuzzy sets will serve for the construction of the fuzzy inference system. Finally, we utilize interval type-2 fuzzy sets in the application of Multiple Attributes Group Decision Making which is called TOPSIS.

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This thesis introduces a novel online set-point modulation (SPM) technique that employs fuzzy logic to adjust the timing and magnitude of control system set-points. After first applying fuzzy logic-enabled SPM to underdamped second order systems for testing purposes, the new scheme is then applied to an electromagnetic transient simulation model of Manitoba Hydro’s existing Ponton SVC system, and the results are then compared to the original SVC system that uses traditional control approaches. Conclusions show that fuzzy logic-based SPM improves the controlled voltage’s transient overshoot response to changes in the voltage set-point.

The problem of the evaluation of fuzzy situations arises quite often in real life. Images, symbols, signals and so on usually are fuzzily described and can be considered as fuzzy situations. So the parameters, which characterize the fuzzy situation, are not only numerical ones, but verbal too, for example, an object can be described as "heavy, little and moves fast". It is difficult to decide something formally about the object with such characterization. Leasing companies meet this problem in contracts classification process too. Accordingly most leasing companies have own contracts classification (recognition) systems, which mostly are statistically based and the similarities and differences between good and bad contracts are not computed. Therefore the demand arises to develop the intellectual recognition system using fuzzy logic. This system should be simply integrating in any leasing company. It also must compute and measure the similarities and differences between good and bad contracts from their evaluation history. Such intellectual system could be as an adviser for business expert. The module of fuzzily characterized situation's evaluation is implemented using: 1) fuzzy sets, 2) fuzzy clustering, 3) fuzzy recognition. The general idea was experimentally investigated using artificially generated data as well as using data from real contracts. The software developed during this research is under preparation to be integrated in companies "Baltic... [to full text]

Wireless sensor nodes are resource constrained and have limited amount of energy. Therefore, designing protocols that conserve energy is an important area of research. Researchers have investigated architectures and topologies that allow energy efficient operation of WSNs. One of the popular techniques in this regard is clustering. A typical clustering protocol contains two main steps: cluster head election and cluster formation. This thesis is aimed at investigation of the cluster formation process. We propose a Fuzzy Logic based approach that uses three descriptors namely: energy level, distance between cluster-head and base station, and distance between the cluster-head and the sensor’s node. We compare our proposed model, FLCFP (Fuzzy Logic Clustering Formation Protocol), with the most popular model, LEACH, which was proposed previously to prolong network lifetime. FLCFP approach is shown to prolong network lifetime. In addition, it is shown that sensor node energy is consumed in a more uniform fashion.

In this thesis, an alternative control method based on Fuzzy Inference System (FIS) is proposed to keep the product composition of a distillation column constant. This study compares a proposed FIS to traditional PID (proportional, integral, derivative) control technique and analyzes the results. The FIS is applied to the control of the tray temperature of the distillation column by using indirect feed split control structure to modulate the steam flow with management of the tray temperature. In turn, this modulation maintains the composition of product at specified levels. Rockwell fuzzy designer is used to develop the fuzzy logic controller. Both a fuzzy logic controller and a PID controller are downloaded in the Rockwell ControlLogix L62 process controller. Chemstations Chemcad simulation software is used to run the distillation column simulations. Simulation results are programmed into L62 process controller to behave as a dynamic distillation column. Results show that the proposed fuzzy logic controller is more tolerant to disturbances in the feed flow and feed composition of the distillation column than the PID controller.

This thesis introduces a novel online set-point modulation (SPM) technique that employs fuzzy logic to adjust the timing and magnitude of control system set-points. After first applying fuzzy logic-enabled SPM to underdamped second order systems for testing purposes, the new scheme is then applied to an electromagnetic transient simulation model of Manitoba Hydro’s existing Ponton SVC system, and the results are then compared to the original SVC system that uses traditional control approaches. Conclusions show that fuzzy logic-based SPM improves the controlled voltage’s transient overshoot response to changes in the voltage set-point.