2성분계 유지혼합용액의 열역학적 고찰 : Methyl ethyl ketone-Alcohol system의 기액평형 Vapor-Liquid Equilibrium of Methyl ethyl ketone-Alcohol System

이철희,심홍섭 영남이공대학 1972 論文集 Vol.1 No.-

The binary vapor-liquid equilibria of methyl ethyl ketone-n-propanol system and methyl ethyl ketone-n-butanol system were measured under the atmospheric pressure. The consistency of vapor-liquid equilibrium data were checked by means of Herington' s consistency test method. It was observed that the logarithmic value of activity coefficient(log γ) and the maximum value of Q-function(Q_(max)) for the liquid phase composition had the same value(log γ=Q_(max)) at^(x) r?????, and that the activity coefficient(γ) and the ratio of vapor pressure of pure component(P_(i)/P^(0)) had the same value(γ=P_(i),/P^(0)) at the liquid phase composition of crossed point on x -y diagram from Raoult's law and from experimental data(x_(c)).

GA와 러프집합을 이용한 퍼지 모델링

이철희,주용석 강원대학교 정보통신연구소 2003 정보통신논문지 Vol.7 No.-

Fuzzy system has in general a drawback that no well-structured and systematic procedure for its design exists. To overcome this difficulty, we suggest a new design method for fuzzy model by combining genetic algorithm(GA) and rough set(RS) theory. Even though the structure and the parameters of fuzzy model may be optimally tuned by GA, it is a time consuming process due the huge serach space. Therefore we introduce rough set theory for rule reduction procedure. As a result, the decrease of learning time and the considerable rate of rule reduction are achieved without loss of useful information. The proposed algorithm is composed of three stages; First stage is quasi-optimization of fuzzy model using GA(coarse tuning). Next the obtained rule base is reduced by rough set concept(rule reduction). Finally only the membership functions of the fixed rules are re-optimized by GA(fine tuning). To check the effectiveness of the suggested algorithm, examples for time series prediction are examined.

퍼지논리 제어기의 비선형성의 정량적 해석

이철희,서선학 江原大學校 産業技術硏究所 1996 産業技術硏究 Vol.16 No.-

In this paper,the nonlinear I/O characteristic of suzzy logic controller is analyzed by using cell concept. Sources of the conlinearity inafuzzy logic controller include thefuzzification, the fuzzy reasoning and the defuzzification. A closed form expression for the defuzzified output is derived in case of a fuzzy logic controller with two inputs, traingular memberships, MacVicar-Whelan type linguistic rules, and direct fuzzy reasoning. As a result, it is shown that fuzzy logic linguistic rules, an direct fuzzy reasoning. As a result, it is shown that fuzzy logic controller is a nonlinear controller. Also its nonlinearity is analyzed with respect to the conventional PID control and the sliding mode control.

특이점과 Gabor 필터를 이용한 효과적인 지문 이미지 분류

이철희,이민섭 강원대학교 정보통신연구소 2003 정보통신논문지 Vol.7 No.-

In fingerprint recognition, an accurate and consistent classification can greatly reduce the matching time for large fingerprint database. Therefore, we propose a new approach to fingerprint classification based on both singular points and Gabor features. We find singular points of fingerprint image by using squared directional field and Poincare index which gives more accurate estimates and requires no postprocessing step. Then the input fingerprint image can be classified into one of 5 classes using the number of singular points and their location. However, it is often impossible to classify the fingerprint image because the number and the position of the estimated singular points are not correct due to noise. In this case Gabor features are extracted from unclassified images using multi-channel 2D Gabor filters and they are classified by using k-nearest neighbor classifier. This method has been tested on the NIST-4 database, and experimental results show that the proposed method is reliable.

오존酸化와 活性炭 濾過에 의한 飮料水의 水質改善에 관하여

李哲熙,金富漢 嶺南大學校 環境問題硏究所 1984 環境硏究 Vol.4 No.2

This research is conducted to find out the effect of ozonization in the removal of hazardous contaminants encountered at Sankyuk Waterworks, and also to modify the conventional treatment plant with ozonization process for producing the sterilized clean water. The ozone treatment rate to maintain 0.4mg/1 of free residual ozone in the gallery infiltered water is 2.1mg/1 for ozone demand flask, 1.8mg/1 for pilot plant. Accordig to increase of iron and manganese in the gallery infiltered water, the turbidity is encreased by ozonization. Through ozonization, sand filtration and activated carbon filtration, the water quality is improved by decreasing above 90% of the organic compounds detergent, algae,E.coli group, iron and manganese, but the ammonia is only removed 51%. As the amount of ammonia containing in the gallery infiltered water is 2.7mg/1, the filtered water through sands is required to aerate with air or to dose more amount of ozone before the activated carbon filtration in order to remove ammonia. When the sand filtration rate is 120m/day, the filter run time after ozonization in the gallery infiltered water is increased to 25% in comparison with the general rapid sand filtration.

비선형 시스템 제어를 위한 퍼지 PID 제어기의 설계 및 해석

이철희,김성호 강원대학교 산업기술연구소 2000 産業技術硏究 Vol.20 No.B

Although Fuzzy Logic Controller(FLC) adopted three terms as input gives better performance, FLC is in general composed of two-term control because of the difficulty in the construction of fuzzy rule base. In this paper, a three-term FLC which is similar to PID control but acts as a nonlinear controller is proposed. To reduce the complexity of the rule base design and to increase efficiency. a simplified fuzzy PID control is induced from a hybrid velocity/position type PID algorithm by sharing a common rule base for both fuzzy PI and fuzzy PD parts. It is simple in structure, easy in implementation, and fast in calculation. The phase plane technique is applied to obtain the rule base for fuzzy two-term control and the resultant rule base is Macvicar-Whelan type. And the membership function is a Gaussian function. The frequency response information is used in tuning of the membership functions. Also a tuning strategy for the scaling factors is proposed based on the relationship between PID gain and the scaling factors. Simulation results show better performance and the effectiveness of the proposed method.

回韓圓板生物膜法으로 都市下水 處理時 圓板表面積과 附着汚尼量에 대하여

李正奎,朴永圭,李哲熙,徐裕德 嶺南大學校 環境問題硏究所 1987 環境硏究 Vol.6 No.2

This paper discussed on the sruface area of disc and the amount of attached biomass by kinetics cinstant at each stage, for treating sewage with rotating biological contactor (RBC). The results are shown as follows; 1. It was found in all experiment that substrate removal could bo divided into two phase. Over 60% of substratre was removed in the first phase. The first phase consisted of the first stage. The remaining substrate removed in the second phase consisting of the second, third and fourth stages. Since the majority of the substrate was removed in the fitst stage and very little in the remaining stages, reducing the distance between the disc in the second phase was necessary for better efficiency in RBC design. 2. The determined saturation constant (㎏) and area capacity constant (p) for calculation of the surface area of disc were ; 69.0, 70.4 at first stage, 88.0, 74.6 at second stage and 137.0, 82.0 ar third and fourth stages, respectively. 3. Thickness of the attached biomass (film) was between 0.34mm and 3.3mm, and the percentages of contained water in the film was approximately 97%. It was also observed that the maximun value of the dry sludge index (DSI) was almost unchanged beyond the effluent concentration of 60㎎/ℓ.

유연구조 퍼지추론 및 비퍼지화

이철희,서선학,Yager, R. 강원대학교 정보통신연구소 1997 정보통신논문지 Vol.1 No.-

In this paper, we suggest a new approach having the flexibility to the problem of fuzzy inference and defuzzification. For fuzzy inference, we observe the fact that it consists of three parts; the determination of firing level of each rule, the determination of degree of coupling between antecedent and consequent of a rule, and the aggregation of all rules. So we soften the paradigm of Mamdani's fuzzy inference model by using S-OWA operators. Also, for defuzzification, we introduced a combinability function to help to more intelligently guide the difuzzification process. And then, we treat it as a kind of clustering problem and apply the basic idea used in the mountain clustering method. The proposed method includes Mamdani's fuzzy inference model and center of gravity method as a special case, and it has the flexibility.

水溶液에서 有機시안化合物의 오존酸化

李哲熙 嶺南大學校 工業技術硏究所 1983 연구보고 Vol.11 No.1

Treatability studies are conducted in oxidizing acrylonitrile, acetonitrile and propionitrile with ozone to investigate the oxidation of organic cyanide compounds in the wastewater of the petrochemical plant. The results are shown as follows; 1. Upon oxidizing acrylonitrile, acetonitrile and propionitrile with ozone, acrylonitrile is much oxidized under acidic solution and the others under the alkaline one. 2. In case of being oxidized acrylonitrile, acetonitrile and propionitrile in aqueous solution with ozone, total organic carbon is much removed under alkaline solution than acidic one. 3. The pH of solutions after oxidizing acrylonitrile, acetonitrile and propionitrile is lower than that of initial solution. Especially in acrylonitrile solution the pH after oxidizing decrease from 9 to 3.4. This suggests that all sorts of oragnic acid produced during ozonizaion might be dissolved in the solution. 4. In case of being oxidized acrylonitrile, acetonitrile and propionitrile under various catalyst with ozone, this is much oxidized more than that of none catalyst. Rany-Nickel catalyst is better than Fe₂O₃ one. 5. Although the present study is limited to the ozonization of nitrile compounds, but the mechanistic studies concerning the the ozonization of nitrile compounds are now in progress in this laboratory.

다중모델기법을 이용한 비선형시스템의 퍼지모델링

이철희,하영기,서선학 江原大學校 産業技術硏究所 1997 産業技術硏究 Vol.17 No.-

In this paper, a new approach to modeling of nonlinear systems using fuzzy theory is presented. To express the various and complex behavior of nonlinear system, we combine multiple model method with hierachical prioritized structure, and the mountain clustering technique is used in partitioning of system. TSK rule structure is adopted to form the fuzzy rules, and Back propagation algorithm is used for learning parameters in consequent parts of the rules. Also we soften the paradigm of Mamdani's inference mechanism by using Yager's S-OWA operators. Computer simulations are performed to verify the effectiveness of the proposed method.