• 대한전기학회논문지:시스템및제어부문D
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• 제53권6호
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• pp.415-424
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• 2004

In this paper, we introduce and investigate a new category of rule-based fuzzy inference system based on Information Granulation(IG). The proposed rule-based fuzzy modeling implements system structure and parameter identification in the efficient form of “If..., then...” statements, and exploits the theory of system optimization and fuzzy implication rules. The form of the fuzzy rules comes with three types of fuzzy inferences: a simplified one that involves conclusions that are fixed numeric values, a linear one where the conclusion part is viewed as a linear function of inputs, and a regression polynomial one as the extended type of the linear one. By the nature of the rule-based fuzzy systems, these fuzzy models are geared toward capturing relationships between information granules. The form of the information granules themselves becomes an important design features of the fuzzy model. Information granulation with the aid of HCM(Hard C-Means) clustering algorithm hell)s determine the initial parameters of rule-based fuzzy model such as the initial apexes of the membership functions and the initial values of polynomial function being used in the Premise and consequence Part of the fuzzy rules. And then the initial Parameters are tuned (adjusted) effectively with the aid of the improved complex method(ICM) and the standard least square method(LSM). In the sequel, the ICM and LSM lead to fine-tuning of the parameters of premise membership functions and consequent polynomial functions in the rules of fuzzy model. An aggregate objective function with a weighting factor is proposed in order to achieve a balance between performance of the fuzzy model. Numerical examples are included to evaluate the performance of the proposed model. They are also contrasted with the performance of the fuzzy models existing in the literature.

• 사상체질의학회지
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• 제11권1호
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• pp.311-327
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• 1999

이제마(李濟馬)는 각 체질의 판단을 위해 체형기상(體形氣像)등의 방법을 제시하였으며, 이를 바탕으로 우리는 여러 가지 다양한 방법의 체질판단을 시도할 수 있다. 그러한 이론의 바탕에는 이제마(李濟馬)의 행위결정론적 사고방식이 강하게 뿌리박고 있다. 이는 "성명론(性命論)"의 '두견요둔(頭肩腰臀)', '이목비구(耳目鼻口)', '함억제복'등의 단어들을 볼 때, 기존처럼 형(形)을 상(象)을 반영하는 객체로 인식하는 것이 아니라, 하나의 부분 주체적 개념으로 인식하고 있는 것을 보면 알 수 있다. 이로 보아 이제마(李濟馬)는 인체의 각 부위에 대하여 기존에 가지고 있던 육체적 기능뿐만 아니라 복잡한 성정적(性情的) 기능도 가지고 있다고 본 것이다. 이러한 고찰과 인체의 외형에 대한 직접적 서술이 있는 "장부론(臟腑論)" 등을 종합해 보면 현재 이용하고 있는 체질판단의 체형기상(體形氣像) 부분에 대하여 일정한 이론을 가지고 설명할 수 있다고 생각하여 다음과 같은 가설을 제시하여 보았다. "사단론(四端論"과 "확충론(據充論)"을 볼 때, 사상인(思象人)의 직부대소(職腑大小)는 태음인(太陽人)의 경우 폐(肺) > 비(脾) > 신(腎) > 간(肝)의 순으로, 소양인(少陽人)은 비(脾) > 폐(肺) > 간(肝) > 신(腎)의 순으로, 태음인(太陰人)의 경우 간(肝) > 신(腎) > 비(脾) > 폐(肺), 소음인(少陰人)은 신(腎) > 간(肝) > 폐(肺) > 비(脾)의 순으로 생각할 수 있으며, "직부론(職腑論)"에서 사람의 형(形)이 형성되는 과정 중에 보이는 '신기혈정(神氣血精)'이라는 개념은 형(形)의 생성과 관련이 있음과 아울러 각 직국(職局) 및 애노희락(哀怒喜樂)의 기운과 통한다라고 할 수 있다. 이러한 관점에서 사상인(四象人)을 분류해 보면, 태음인(太陽人)을 신기정혈형(神氣精血型), 소양인(少陽人)을 기신혈정형(氣神血精型), 태음인(太陰人)을 혈정기신형(血精氣神型), 소음인(少陰人)을 정혈신기형(精血神氣型)으로 분류할 수 있을 것이다. 이러한 역량관계에 따라 각 체질의 외형에 대하여 일정한 설명방법을 도입해 보았으며, 이러한 시도를 바탕으로 사상의학의 형상에 대한 논의가 활발해졌으면 하는 바램이다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.720-723
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• 2005

Ship motion is a complex controlled process with several hydrodynamic parameters that vary in wide ranges with respect to ship load condition, speed and surrounding conditions (such as wind, current, tide, etc.). Therefore, to effectively control ships in a designed track is always an important task for ship masters. This paper presents an effective adaptive autopilot ships that ensure the optimal accuracy, economy and stability characteristics. The PID control methodology is modified and parameters of a PID controller is designed to satisfy conditions for an optimal objective function that comprised by heading error, resistance and drift during changing course, and loss of surge velocity or fuel consumption. Designing of the controller for course changing process is based on the Model Reference Adaptive System (MRAS) control theory, while as designing of the automatic course keeping process is based on the Self Tuning Regulator (STR) control theory. Simulation (using MATLAB software) in various disturbance conditions shows that in comparison with conventional PID autopilots, the designed autopilot has several notable advantages: higher course turning speed, lower swing of ship bow even in strong waves and winds, high accuracy of course keeping, shorter time of rudder actions smaller times of changing rudder direction.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권12호
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• pp.5116-5134
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• 2015

In this paper, due to the network security defense is mainly static defense, a dynamic classification network security defense strategy model is proposed by analyzing the security situation of complex computer network. According to the network security impact parameters, eight security elements and classification standard are obtained. At the same time, the dynamic classification algorithm based on fuzzy theory is also presented. The experimental analysis results show that the proposed model and algorithm are feasible and effective. The model is a good way to solve a safety problem that the static defense cannot cope with tactics and lack of dynamic change.

• KIEAE Journal
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• 제11권6호
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• pp.117-125
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• 2011

As quality of life improves recently, people began to pay more attention to outdoor environment and outdoor activities. In case of the U.S.A., community garden is utilized as space for plant cultivation and horticulture activities and the space is also used for complex activities such as education, play, leisure and rest. At the same time, such diverse activities are linked with creating social and economic wealth, thus creating sustainable values in the community. This study targets to identify the social and economic effects of community garden. For this purpose, the study analyzes the detailed cases of community gardens in the U.S. and analyzed the contents of the study based on the theory of social capital. In case of Korea, community gardens are operated in the form of urbane farming and parks in most cases but it is desirable in terms of contribution to the community and sustainability to manage the community gardens with space characteristics and programs that set up communities by gathering many residents in the community. It is necessary to approach the matter of community garden comprehensively and to set up comprehensive and complex plans to form community gardens. This study is expected to function as an important base for such purpose.

• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.1935-1944
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• 2018

With the increase of the production of energy from renewable, it becomes important to look at techniques to store this energy. Therefore, a single winding bearingless flywheel motor (SWBFM) specially for flywheel energy storage system is introduced. For the control system of SWBFM, coupling between the torque and the suspension subsystems exists inevitably. It is necessary to build a reasonable radial force mathematical model to precisely control SWBFM. However, SWBFM has twelve independently controlled windings which leads to high-order matrix transformation and complex differential calculation in the process of mathematical modeling based on virtual displacement method. In this frame, a Maxwell tensor modeling method which is no need the detailed derivation and complex theoretical computation is present. Moreover, it possesses advantages of universality, accuracy, and directness. The fringing magnetic path is improved from straight and circular lines to elliptical line and the rationality of elliptical line is verified by virtual displacement theory according to electromagnetic torque characteristics. A correction function is taken to increase the model accuracy based on finite element analysis. Simulation and experimental results show that the control system of SWBFM with radial force mathematical model based on Maxwell tensor method is feasible and has high precision.

• 한국항만학회지
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• 제12권1호
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• pp.9-17
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• 1998

The evaluation structure of complex problems is composed of multi-attributes and hierarchy. A many studies were existed on this problems, but that based on the assumption that the evaluation elements were independent. The actual evaluation problems have the complexity, ambiguity and interlinkage among the elements. In this situation, the fuzzy evaluation process is very effective in settling the complex problems. For evaluation of large scale hierarchical MADM problem, the fuzzy evaluation algorithm is developed in this paper, and that is centering on the identification of fuzzy measures. In this study, we newly identified the weight and interaction among the evaluation attributes. The results of this study are as follows: we can identified the hierarchical structure of the evaluation problem which is composed of the evaluation structure, function and hierarchy; we improved the existed weighting method which could be accomplished by normalizing process, considering the uncertainty and new weight integrating method which come from Dempster-Shafer theory. And we take into account the interaction properties among more than 3 evaluation attributes, which can be compared with the existed studies in which only 2 evaluation attributes taked into account.

• Composites Research
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• 제18권3호
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• pp.14-20
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• 2005

본 논문에서는 카본 블랙/에폭시 복합재료 적층판의 유전율에 대한 연구를 수행하였다. 유전율 측정은 $1\;GHz\~18\;GHz$의 주파수 영역에서 수행하였으며, 복합재료의 유전율은 카본 블랙 함유율의 주파수의 함수로 얻을 수 있었다. 유전율 및 전기 전도도의 주파수 특성은 Percolation 이론에서 제시된 경향을 만족하였다. 측정에 사용된 주파수 영역은 전기 전도도가 주파수의 함수관계를 가지는 최소 주파수인 임계주파수보다 크며, 복합재료의 유전율과 전기 전도도는 카본 블랙의 함유량과 일정한 관계를 가졌다. 본 연구에서는, 카본 블랙의 함유율에 따른 복합재료의 유전율을 모사하는 혼합법칙을 얻기 위하여 Lichteneker-Rother 방정식에 기초한 새로운 방법이 제시되었으며, 혼합법칙으로 계산된 복합재료 유전율 모사 결과는 실험적으로 얻은 유전율을 비교적 잘 모사하는 결과를 얻을 수 있었다.

• 대한기계학회논문집B
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• 제29권6호
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• pp.671-686
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• 2005

The transient nature and complex geometries of two-phase gas-liquid flows cause fundamental difficulties when measuring flow velocity using an electromagnetic flowmeter. Recently, a current-sensing flowmeter was introduced to obtain measurements with high temporal resolution (Ahn et al.). In this study, current-sensing flowmeter theory was applied to measure the fast velocity transients in slug flows. The velocity fields of axisymmetric gas-liquid slug flow in a vertical pipe were obtained using Volume-of-Fluid (VOF) method, and the virtual potential distributions for the electrodes of finite size were also computed using the finite volume method for simulating slug flow. The output signal prediction for slug flow was carried out from the velocity and virtual potential (or weight function) fields. The flowmeter was numerically calibrated to obtain the cross-sectional liquid mean velocity at an electrode plane from the predicted output signal. Two calibration parameters are proposed for this procedure: a flow pattern coefficient and a localization parameter. The flow pattern coefficient was defined by the ratio of the liquid resistance between the electrodes for two-phase flow with respect to that for single-phase flow, and the localization parameter was introduced to avoid errors in the flowmeter readings caused by liquid acceleration or deceleration around the electrodes. These parameters were also calculated from the computed velocity and virtual potential fields. The results can be used to obtain the liquid mean velocity from the slug flow signal measured by a current-sensing flowmeter.

• Asia pacific journal of information systems
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• 제7권2호
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• pp.225-266
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• 1997

A Causal Transition Model of the IT impact on organization is proposed. The model is based upon the premise that the IT impact is a multi-phase, multi-realm phenomenon, and that the IT impact in one organizational realm logically transpires to another realm, thus forming complex causal webs among them. Two exploratory research studies, the one qualitative and the other quantitative, were conductea to validate the model in a setting involving major structural reorganization of the organizations' IT function. The research results provide support for the general theory structure of the model. The findings include: ⅰ) the IT impact manifests on multiple organizational realms, with different degrees of strength, ⅱ) the impact on the realms follow a particular causal transition path among them, and ⅲ) the IT impact manifests on and through the information processing aspect of work. The results, however, indicate that people's perception of the IT impact is strongly mitigated by the IT relevance of work, and that the organization is affected as much by the structural arrangement surrounding and accompanying the IT as by the technology itself, suggesting that the IT impact is an organizational phenomenon as well as a technological phenomenon. The implications of the research results are discussed at the end.