• 대한기계학회논문집A
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• 제20권3호
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• pp.765-774
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• 1996

Computer Integrated Manufacturing(CIM) requires models of manufacturing processes to be implemented on the computer. These models are typically used for determining optimal process control parameters or designing adaptive control systems. In spite of the progress made in the mechanistic modeling, however, empirical models derived from experimental data play a maior role in manufacturing process modeling. This paper describes the development of a meural metwork medel for injection molding. This paper describes the development of a nueral network model for injection molding process. The model uses the CAE analysis data based on Taguchi method. The developed model is, then, compared with the traditional polynomial regression model to assess the applicabilit in practice.

• Journal of Communications and Networks
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• 제12권5호
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• pp.411-432
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• 2010

We consider three different secure broadcasting scenarios: i) Broadcast channels with common and confidential messages (BCC), ii) multi-receiver wiretap channels with public and confidential messages, and iii) compound wiretap channels. The BCC is a broadcast channel with two users, where in addition to the common message sent to both users, a private message, which needs to be kept hidden as much as possible from the other user, is sent to each user. In this model, each user treats the other user as an eavesdropper. The multi-receiver wiretap channel is a broadcast channel with two legitimate users and an external eavesdropper, where the transmitter sends a pair of public and confidential messages to each legitimate user. Although there is no secrecy concern about the public messages, the confidential messages need to be kept perfectly secret from the eavesdropper. The compound wiretap channel is a compound broadcast channel with a group of legitimate users and a group of eavesdroppers. In this model, the transmitter sends a common confidential message to the legitimate users, and this confidential message needs to be kept perfectly secret from all eavesdroppers. In this paper, we provide a survey of the existing information-theoretic results for these three forms of secure broadcasting problems, with a closer look at the Gaussian multiple-input multiple-output (MIMO) channel models. We also present the existing results for the more general discrete memoryless channel models, as they are often the first step in obtaining the capacity results for the corresponding Gaussian MIMO channel models.

• 한국컴퓨터그래픽스학회논문지
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• 제4권1호
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• pp.11-19
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• 1998

오일러 연산과 집합 연산과 같은 비다양체 위상 연산은 모델링의 다양한 환경을 제공한다. 이들 연산들은 주어진 모델의 위상 정보를 적합하게 유지하도록 하기 위하여 기하학적인 문제를 발생시킨다. 꼭지점, 모서리와 면과 같은 요소들이 서로 접촉할 때 이들 연산의 내부에서 수행되는 접합 연산은 비다양체 모델의 위상을 수정하는 기본적인 방법이다. 비다양체 모델을 접합할 때는 위상 관계를 추론하여야 한다. 위상 관계의 추론 방법은 위상학적인 방법과 기하학적인 방법의 2 가지 경우로 분류할 수 있다. 위상학적인 방법은 저장되어 있는 위상 정보만을 이용하여 위상 관계를 추론한다. 반면에, 기하학적인 방법은 접합이 일어나는 부분적인 영역에서 기하학적인 형상을 고려하여 위상의 관계를 찾아내는 방법이다. 본 연구에서는 이들 중에서 기하학적인 방법에 관하여 기술한다.

• Journal of information and communication convergence engineering
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• 제14권2호
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• pp.115-121
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• 2016

Currently there is a lack of literature on SPICE-level models of double-gate (DG) tunnel field-effect transistors (TFETs). A DG TFET compact model is presented in this work that is used to develop a SPICE model for DG TFETs implemented with Verilog-A language. The compact modeling approach presented in this work integrates several issues in previously published compact models including ambiguity about the use of tunneling parameters A_k and B_k, and the use of a universal equation for calculating the surface potential of DG TFETs in all regimes of operation to deliver a general SPICE modeling procedure for DG TFETs. The SPICE model of DG TFET captures the drain current-gate voltage (I_ds-V_gs) characteristics of DG TFET reasonably well and offers a definite computational advantage over TCAD. The general SPICE modeling procedure presented here could be used to develop SPICE models for any combination of structural parameters of DG TFETs.

• Journal of Electrical Engineering and Technology
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• 제10권2호
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• pp.670-675
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• 2015

Medical imaging is one of the most powerful tools for gaining information about internal organs and tissues. It is a challenging task to develop sophisticated image analysis methods in order to improve the accuracy of diagnosis. The objective of this paper is to develop a Computer Aided Diagnostics (CAD) scheme for Brain Tumour detection from Magnetic Resonance Image (MRI) using active contour models and to investigate with several approaches for improving CAD performances. The problem in clinical medicine is the automatic detection of brain Tumours with maximum accuracy and in less time. This work involves the following steps: i) Segmentation performed by Fuzzy Clustering with Level Set Method (FCMLSM) and performance is compared with snake models based on Balloon force and Gradient Vector Force (GVF), Distance Regularized Level Set Method (DRLSE). ii) Feature extraction done by Shape and Texture based features. iii) Brain Tumour detection performed by various tree classifiers. Based on investigation FCMLSM is well suited segmentation method and Random Forest is the most optimum classifier for this problem. This method gives accuracy of 97% and with minimum classification error. The time taken to detect Tumour is approximately 2 mins for an examination (30 slices).

• 한국산학기술학회논문지
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• 제11권4호
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• pp.1307-1317
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• 2010

응용 소프트웨어 시스템의 신뢰성을 평가하기 위한 모형은 매우 다양하게 개발되어 있다. 그러나 이렇게 개발된 대부분의 모형에서 보면, 모수의 추정방법이 너무 복잡하다. 그러므로 소프트웨어를 생산하는 산업현장에서 적용하기에는 불편한 점이 너무 많다. 그래서 본 연구에서는 간편하게 현장에서 적용할 수 있는 신뢰성 평가모형을 개발한다. 그리고 시스템을 이용하여 신뢰성을 평가하여 기존의 신뢰성 평가모형과 차이가 없음을 증명하고자 한다. 이렇게 효과가 입증되면, 현장에서 소프트웨어 시스템을 개발하고 있는 개발자들이 편리하게 신뢰성을 평가해 볼 수 있도록 하게 될 것이다. 따라서 소프트웨어 시스템에 대한 신뢰도를 높이고, 처리된 정보에 대한 신뢰도를 향상시키는데 크게 기여할 수 있을 것으로 본다.

• Environmental Engineering Research
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• 제14권4호
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• pp.200-210
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• 2009

The modern era of water quality modeling in the United States began in the 1960s. Pushed by advances in computer technology as well as environmental sciences, water quality modeling evolved through five broad periods: (1) initial model development with mainframe computers (1960s - mid 1970s), (2) model refinement and generalization with minicomputers (mid 1970s - mid 1980s), (3) model standardization and support with microcomputers (mid 1980s - mid 1990s), (4) better model access and performance with faster desktop computers running Windows and local area networks linked to the Internet (mid 1990s - early 2000s), and (5) model integration and widespread use of the Internet (early 2000s - present). Improved computer technology continues to drive improvements in water quality models, including more detailed environmental analysis (spatially and temporally), better user interfaces and GIS software, more accessibility to environmental data from on-line repositories, and more robust modeling frameworks linking hydrodynamics, water quality, watershed and atmospheric models. Driven by regulatory needs and advancing technology, water quality modeling will continue to improve to better address more complicated water bodies and pollutant types, and more complicated management questions. This manuscript describes historical trends in water quality model development in the United States, reviews current efforts, and projects promising future directions.

• 한국컴퓨터그래픽스학회논문지
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• 제4권2호
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• pp.29-32
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• 1998

다면체를 부드럽게 렌더링하기 위해서는 각 꼭지점에서의 법선 벡터가 필요하다. 기장 흔히 쓰는 법선 벡터 계산 방법은 꼭지점 주변 면들의 법선 벡터들을 평균하는 것인데, 이 방법은 면들이 어떻게 분할 되어 있는지에 영향을 받으며, 따라서 비록 모델을 연속되게 변형하더라도 면 분할을 행하고 나면 법선 벡터들이 연속되지 않게 변할 수 있다. 본 논문에서는 이러한 문제점들을 해결하기 위하여 기존의 방법을 약간 변형한 법선 벡터 계산 방법을 제시한다. 이 방법에서는 꼭지점 주변 면들의 법선 벡터를 가중합하여 구하는데, 한 면의 가중치는 꼭지점에 걸쳐있는 두 모서리가 이루는 각으로 정한다.

• 대한인간공학회지
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• 제31권3호
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• pp.463-467
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• 2012

This study aims to empirically investigate population stereotype of burner-control linkage of four-stove gas range for Koreans. Background: The previous studies' results for gas range stereotypes were different depending upon methods adopted, i.e., whether using questionnaires, computer simulation or physical models. It is known that the physical model experiment should not be methodologically replaced by the computer simulation or paper-and-pencil tests. Stereotype of gas range for Koreans was surveyed based on questionnaires, but has not been dealt with by using physical models. Method: An experiment was conducted to investigate stereotype of four-burner gas range, in which 32 subjects participated and a real gas range available in the market was bought and used. Four types of burner-control linkage were used as independent variable, and reaction time as dependent variable. Results: ANOVA revealed that four types of burner-control linkage and subjects' gender were not significant on reaction time. Duncan's multiple range test showed that reaction times for type III was significantly lower than those for the other three types of burner-control linkage(${\alpha}$=0.05). Conclusion: It is concluded based on the results of this study that stereotype of gas range for Koreans is type III. This is in agreement with results of existing studies using questionnaire survey, while different from those based on physical models. Application: The results of this study would be useful as an ergonomic guideline when designing gas ranges or similar equipments for minimizing operation errors.

• Nuclear Engineering and Technology
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• 제47권2호
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• pp.176-186
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• 2015

Pattern classifications have become important tools for fault diagnosis in nuclear power plants (NPP). However, it is often difficult to obtain training data under fault conditions to train a supervised classification model. By contrast, normal plant operating data can be easily made available through increased deployment of supervisory, control, and data acquisition systems. Such data can also be used to train classification models to improve the performance of fault diagnosis scheme. In this paper, a fault diagnosis scheme based on semisupervised classification (SSC) scheme is developed. In this scheme, new measurements collected from the plant are integrated with data observed under fault conditions to train the SSC models. The trained models are subsequently applied to new measurements for fault diagnosis. In comparison with supervised classifiers, the proposed scheme requires significantly fewer data collected under fault conditions to train the classifier. The developed scheme has been validated using different fault scenarios on a desktop NPP simulator as well as on a physical NPP simulator using a graph-based SSC algorithm. All the considered faults have been successfully diagnosed. The results have demonstrated that SSC is a promising tool for fault diagnosis in NPPs.