• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 봄 학술발표회논문집
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• pp.397-404
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• 2000

The research of the computer-aided analysis and design of steel structures has continuously evolved. Despite the importance of connection in steel structures, the design process of connections is inefficient in present. The purpose of this study is to help engineer in connection design process. In this paper, prototype of automatic connection design module in integrated system for steel structures is proposed. The main methodology is based on bottom-up approach to simplify and formalize product model. Expert system is used to help engineer for selecting steel connection type. Object-oriented analysis and modeling will improve the expansion of knowledge-base. The design for connection was done according to the design specifications of connections of AISC

• Bulletin of the Korean Chemical Society
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• 제24권6호
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• pp.757-762
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• 2003

Since theoretical investigations of gas phase clusters enable the evaluation of intrinsic molecular properties and intermolecular interactions, one can predict the macroscopic properties of bulk matter, from a microscopic determination of the properties of individual atoms, molecules, or clusters. Based on the insights obtained from theoretical investigations of the properties of a large number of cluster systems (ranging from simple water clusters to large π-systems), we have investigated the properties of various novel molecular systems including endo/exohedral fullerenes, nanotori, nonlinear optical materials, ionophores/receptors, polypeptides, enzymes, organic nanotubes, nanowires, and electronic and nano-mechanical molecular devices. The present minireview highlights some of the interesting results obtained in the course of our extensive theoretical investigations of clusters and nanomaterials.

• 말소리와 음성과학
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• 제1권2호
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• pp.15-22
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• 2009

Prominence of speech, which is often called 'accent,' affects the fluency of speaking American English greatly. In this paper, we present an accurate prominence detection method that can be utilized in computer-aided language learning (CALL) systems. We employed pitch movement, overall syllable energy, 300-2200 Hz band energy, syllable duration, and spectral and temporal correlation as features to model the prominence of speech. After the features for vowel syllables of speech were extracted, prominent syllables were classified by SVM (Support Vector Machine). To further improve accuracy, the differences in characteristics of neighboring syllables were added as additional features. We also applied a speech recognizer to extract more precise syllable boundaries. The performance of our prominence detector was measured based on the Intonational Variation in English (IViE) speech corpus. We obtained 84.9% accuracy which is about 10% higher than previous research.

• 대한산업공학회지
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• 제20권3호
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• pp.125-137
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• 1994

Manufacturing environs constantly change, and any efficient software system to be used in manufacturing must be able to adapt to the varying situations. In a CAPP (Computer-Aided Process Planning) system, a learning capability is necessary for the CAPP system to do change along with the manufacturing system. Unfortunately only a few CAPP systems currently possess learning capabilities. This research aims at the development of a learning system which can increase the knowledge in a CAPP system. A part in the system is represented by frames and described interactively. The process information and process planning logic is represented using a decision tree. The knowledge expansion is carried out through an interactive expansion of the decision tree according to human advice. Algorithms for decision tree modification are developed. A path can be recommended for an unknown part of limited scope. The processes are selected according to the criterion such as minimum time or minimum cost. The decision tree, and the process planning and learning procedures are formally defined.

• Journal of Advanced Marine Engineering and Technology
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• 제15권5호
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• pp.30-37
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• 1991

Steam ejector systems are widely used for the evacuation systems because of their high working confidence and simlicity. And recently these are used as the thermo-compressors in various energy saving systems. In this practical experiment, we have obtained the results as follows : (1) The velocity coefficient of the motive steam nozzle was 0.92-0.98. (2) The optimal area ratio was 0.00625 at pressure ratio 5.2 and expansion ratio 101.3. (3) The performance and efficiency of the steam ejector were mainly affected by the axial position of nozzle. (4) The good performance of the domestic manufactured steam ejector was confirmed in comparison with the foreign one. And by experimental results, we have carried out the improvement of Computer Aided Design Program of steam ejector which will be helpful for systematic research into the steam ejector.

• 한국기계가공학회지
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• 제19권9호
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• pp.71-77
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• 2020

In recent years, as a consequence of the technological advancements in the automobile industry and changes in consumer demands, the reduction of noise inside vehicles rather than vehicle performance has increasingly become an important factor of interest. To date, most studies have focused on noise and vibration reduction techniques for the engine and drive system of vehicles. In this research, a comparative analysis for reducing the effect of vehicle seatbelts on the transient response is performed using the test of vehicle conditions and transient response analysis in accordance with seatbelt conditions. After the sensitivity analysis, the specifications for improvement were designed based on the transient response analysis. It was confirmed that the transient response characteristics were improved by the transient response analysis and vehicle conditions test. Through computer-aided engineering, the transient response characteristics of seatbelts were checked with less cost and time.

• Journal of Mechanical Science and Technology
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• 제20권12호
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• pp.2025-2033
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• 2006

This paper presents, the design of a latch mechanism for wafer containers in a standard mechanical interface environment. For an integrated circuits fabrication factory, the standard mechanical interfaced wafer container is an effective tool to prevent wafers from particle contamination during wafer storage, transporting or transferring. The latch mechanism inside the container door is used to latch and further seal the wafer container for safety and air quality. Kinematic characteristics of the mechanism are established by analyzing the required functions of the mechanisms. Based on these characteristics, a methodology for enumerating feasible latch mechanisms is developed. New mechanisms with one degree-of-freedom and up to five links are generated. An optimum design is also identified with respect to the criteria pertinent to the application. The computer-aided simulation is also built to verify the design.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제7권2호
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• pp.101-117
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• 2003

In this paper, we give examples of models we have created for use in university mathematics courses. We explain the concept of linear transformation, investigate the roles of each component of 2 ${\times}$ 2 and 3 ${\times}$ 3 transformation matrices, consider the relation between sound and trigonometry, visualize the Riemann sum, the volume of surfaces of revolution and the area of unit circle. This paper illustrates how one can use Mathematica to visualize abstract mathematical concepts, thus enabling students to understand mathematics problems effectively in class. Development of these kinds of teaching and learning models can stimulate the students' curiosity about mathematics and increase their interest.

• 한국정밀공학회지
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• 제16권12호
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• pp.109-118
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• 1999

The objective of this research is to develop an effective inspection planning strategy for sculpture surfaces in OMM(On-Machine Measurement) process. As a first step, effective measuring point locations are determined to obtain optimum results for given sampling numbers. Two measuring point selection methods are suggested in this study based on newly proposed CAD/CAM/CAI integration concept: (1) by the prediction of cutting errors, (2) by considering cutter contact points to avoid the measurement errors caused by cusps. As a next step, the TSP(Traveling Salesman Problem)algorithm is applied to minimize the probe moving distance. Appropriate simulations and experiments are performed to verify the proposed inspection planning strategy in this study, and the results are analyzed.

• 한국해양공학회지
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• 제23권6호
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• pp.17-22
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• 2009

This study presents an investigation of the characteristics of piezoelectric sensors whose main utilization is to measure impact pressure. The piezoelectric sensors were tested from several points of view. Their characteristics were investigated for repeatability, the effect of the diameter, temperature effect, water purity, flush mounting, and AC and DC coupling. Out of these, it was revealed that the temperature effect is very significant. The characteristics of the AC and DC coupling are also very important in understanding the time history of the impact pressure.