• 한국정보통신학회논문지
• /
• 제16권8호
• /
• pp.1717-1724
• /
• 2012

온라인에서 사용자들의 사회적 관계 정보는 상업 활동의 추천 정보와 같은 다른 서비스에 사용될 수 있는 유용한 정보이다. 이 때문에 소셜 네트워크의 시각화를 통한 분석이 많이 연구되고 있다. 기존의 대부분의 시각화 방법은 복잡한 다차원 그래프를 통하여 소셜 네트워크상의 사용자의 관계를 집중적으로 표현하고 있다. 그러나 이러한 방법은 개인 사용자 중심으로 사회관계의 중요도를 직관적으로 파악하기 힘들다. 이러한 문제를 해결하기 위해서 본 논문은 사용자의 상관 관계와 네트워크 노드의 사용자 관계를 이용한 새로운 시각화 방법을 제안한다. 제안방법은 사용자 메시지가 반영된 네트워크상의 내부관계와 네트워크 노드간의 외부관계를 사용하여 사용자간의 관계를 계층적으로 시각화한다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제51권5호
• /
• pp.234-241
• /
• 2002

An optical pickup actuator is an objective-lens-moving mechanism that provides a means to follow the disk displacement accurately(1). In this paper, a slim type optical pickup actuator for Notebook PCs is analyzed and designed to improve the driving sensitivity A three dimensional equivalent magnetic circuit network method (3D-EMCN method) is proposed for an analysis method which provides better characteristics in both precision and computation time of analysis comparing with a commercial three-dimensional finite element (3D-FEM) codes. To verify the validity of proposed method, we made a comparison between the analysis results and the experimental ones. We also compared this analysis results with 3D-FEM results. Among the several optimal algorithm, we adopt a niching genetic algorithm, which renders a set of the multiple optimal solutions. RCS (Restricted Competition Selection) niching genetic algorithm is used for optimal design of the actuator's performance. Recently, the pickup actuator needs additional driving structure for radial and tangential tilting motion to obtain better pick-up performance. So we applied the proposed method to the model containing tilting coils.

• International Journal of Air-Conditioning and Refrigeration
• /
• 제6권
• /
• pp.1-13
• /
• 1998

The basic heat transfer process that occurs in a building can best be illustrated by an electrical circuit network. Present paper reports the dynamic simulation of annual energy consumption in an office building by the thermal resistance capacitance network method. Unsteady thermal behaviors and annual energy consumption in an office building were examined in detail by solving the simultaneous circuit equations of thermal network. The results are used to evaluate the accuracy of the modified BIN method for the energy consumption analysis of a large building. Present thermal resistance-capacitance method predicts annual energy consumption of an office building with the same accuracy as that of response factor method. However, the modified BIN method gives 15% lower annual heating load and 25% lower cooling load than those from the present method. Equipment annual energy consumptions for fan, boiler and chiller in the HVAC system are also calculated for various control systems as CAV, VAV, FCU+VAV and FCU+CAV. FCU+CAV system appears to consume minimum annual energy among them.

• ETRI Journal
• /
• 제26권4호
• /
• pp.371-374
• /
• 2004

We propose and demonstrate a fabrication method of chirped fiber gratings by a thermal diffusion process. The method could suggest a direction for a simple and cost-effective implementation of chirped fiber grating-based devices.

• 한국지능시스템학회:학술대회논문집
• /
• 한국퍼지및지능시스템학회 1998년도 춘계학술대회 학술발표 논문집
• /
• pp.49-52
• /
• 1998

Neural Network has good performance in pattern classification, control and many other fields by learning ability. However, there is effective rule or systematic approach to determine optimal structure. In this paper, we propose a new method to find optimal structure of feed-forward multi-layer neural network as a kind of pruning method. That eliminating redundant elements of neural network. To find redundant elements we analysis error and weight changing with Rough Set Theory, in condition of executing back-propagation leaning algorithm.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2004년도 하계학술대회 논문집 D
• /
• pp.2383-2385
• /
• 2004

Network uncertainties can vary the stability property of networked control system. Therefore, the performance and the stability variation of networked control system due to network uncertainties must be considered first in designing networked control system. In this paper, we present a new stability analysis method of networked control system with data loss and time delay. The proposed method can determine maximum allowable time delay and allowable transmission rate that preserves stability performance of networked control system. The results of the simulation validate effectiveness of our stability analysis methods.

• 한국정밀공학회지
• /
• 제32권5호
• /
• pp.463-470
• /
• 2015

Solar cell is typical representative of renewable green energy. Silicon wafer contributes about 66 percent to its cost structure. In its manufacturing, micro-cracks are often occurred due to manufacturing process such as wire sawing, grinding and cleaning. Their detection and classification are important to process feedback information. In this paper, a classification method of micro-cracks is proposed, based on the fusion of principal component analysis(PCA) and neural network. The proposed method shows that it gives higher results than single application of two methods, in terms of shape and size classification of micro-cracks.

• International Journal of Advanced Culture Technology
• /
• 제6권3호
• /
• pp.142-150
• /
• 2018

This paper describes the algorithm that lowers the dimension, maintains the object recognition and significantly reduces the eigenspace configuration time by combining the edge orientation histogram and principle component analysis. By using the detected object region as a recognition input image, in this paper the object recognition method combined with principle component analysis and the multi-layer network which is one of the intelligent classification was suggested and its performance was evaluated. As a pre-processing algorithm of input object image, this method computes the eigenspace through principle component analysis and expresses the training images with it as a fundamental vector. Each image takes the set of weights for the fundamental vector as a feature vector and it reduces the dimension of image at the same time, and then the object recognition is performed by inputting the multi-layer neural network.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제53권2호
• /
• pp.63-68
• /
• 2004

This paper presents an approach to optimum design of Moving Magnet Type Linear Oscillatory Actuator(MM-LOA). The Finite Element Method is applied to characteristic parameters for characteristic analysis and in order to reduce modeling time and efforts, the moving model node technique is used. In addition the neural network is used to reduce computational time of analysis according to changing design variable. To confirm the validity of this study, optimum design results are compared with results of analysis procedure that is verified by experiment.

• Nuclear Engineering and Technology
• /
• 제56권10호
• /
• pp.4149-4157
• /
• 2024

Welding processes are used to connect several components in nuclear power plants. These welding processes can induce residual stress in welding joints, which has been identified as a significant factor in primary water stress corrosion cracking. Consequently, the assessment of welding residual stress plays a crucial role in determining the structural integrity of welded joints. In this study, a deep fuzzy neural networks (DFNN) with a rule-dropout method, which is an artificial intelligence (AI) method, was used to predict the residual stress of dissimilar metal welding. ABAQUS, a finite element analysis program, was used as the data collection tool to develop the AI model, and 6300 data instances were collected under 150 analysis conditions. A rule-dropout method and genetic algorithm were used to optimize the estimation performance of the DFNN model. DFNN with the rule-dropout model was compared to a deep neural network method, known as a general deep learning method, to evaluate the estimation performance of DFNN. In addition, a fuzzy neural network method and a cascaded support vector regression method conducted in previous studies were compared. Consequently, the estimation performance of the DFNN with the rule-dropout model was better than those of the comparison methods. The welding residual stress estimation results of this study are expected to contribute to the evaluation of the structural integrity of welded joints.