• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2002년도 춘계학술대회논문집
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• pp.161-176
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• 2002

Collision avoidance is the most important part of a small vessel. Small and mediurn sized ships are surprisingly poor targets for radar reflection and are frequently in danger of being overrun by large vessels, even under good condition of visibility. One of the best way to prevent collisions at sea is to use as large and well designed a radar reflector. Thus, RCS(Radar Cross Section) increase is key element in the design of radar reflector. Radar Reflectors are normally classified into active-type and passive-type. In this paper, the RCS increase methods for passive-type reflector through shaping are explained, and analyzed with RCS performance test by computer simulation. As results from analysis, It is shown that the effective diameter of radar reflector is over 10 λ to provide a return above the threshold RCS of 25m$^2$, lower limit of detectability using X-band radar in a moderate sea.

• 한국정밀공학회지
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• 제33권8호
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• pp.641-646
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• 2016

The best method of measuring wood diameter is a contact-type device: however, obtaining an accurate result can be problematic under certain circumstances. In this study, we used a laser beam and a CCD camera that did not require contact with wood. The wood is illuminated by the laser beam, and the CCD camera captures this illumination. The measurement results were determined by processing of the captured image sequences. This paper explains the use of image processing and laser systems for measurement of wood under circumstances in which physical contact is impossible.

• 대한전기학회논문지
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• 제39권1호
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• pp.16-21
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• 1990

A Knowledge based expert system is a computer program that emulates the reasoning process of a human expert in a specific problem domain. Expert system has the potential to solve a wide range of problems which require knowledge about the problem rather than a purely analytical approach. This papaer presents the application of knowledge based expert system to power system fault diagnosis. The contents of expert system develpped in this paper is judgement of fault section from a given alarm sets and production of all possible hypothesis for the single fault. Both relay failures and circuit breaker failures are considered simultaneously. Although many types of relay are used in actual system, experts recognize ones as several typical signals corresponding to the fault types. Therefore relays are classified into several types. The expert system is written in an artificial intelligence language "PROLOG" . Best-first search method is used for problem solving. Both forward chaining and backward chaining schemes are used in reasoning process. The application to a part of actual power system proves the availability of the developed expert system.

• 에너지공학
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• 제23권2호
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• pp.114-118
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• 2014

The need to maximize the exhaust pipe inside surface and to minimize exhaust resistance And Find the best point between the exhaust and the duration of contact between the two surfaces. Exhaust gas mass flow On the whole cross section of catalytic converters more uniform distribution will contribute to its usability. Based on the flow rate of fluid traces given color, Exhaust fluid resistance in the porous catalyst can be estimated, from the efficiency of the catalytic converter that is very important.

• 한국안전학회지
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• 제2권3호
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• pp.5-11
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• 1987

In this study, a mild steel (SS41) of the carbon steel, a spring steel (SUP-9), and stainless steel (SUS 304) of the special gceel, etc, are adopted as the experimental materrials and are weded by $CO_2$(SS41, SUP-9), TIG (SUS304), respectively. And the residual stress distribution and fracture behavior at the welded zone are examined according to annealing temperatures of four section involving as welded. As a consequence, the best annealing temperatures that the residual stress is removed enough and mechanical properties are very suitable are at 90$0^{\circ}C$ (SS41), 75$0^{\circ}C$ (SUP-9), 110$0^{\circ}C$ (SUS 304), respectively.

• 한국안전학회지
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• 제23권6호
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• pp.108-114
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• 2008

Although FRP is relatively new material for constructional use, there are several commercial GFRP bridge decks available today. In this paper we first set variables which decide the design of a GFRP deck based on commercial products. Under the assumption of linear elastic behavior under DB24 load, all the conditions of stability and serviceability are considered. We seek the best solution which minimizes the cross section area using genetic algorithm. The optimal solution shows that the shape is close to the ASSET deck with larger angle of the web and smaller area.

• Nuclear Engineering and Technology
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• 제38권7호
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• pp.665-674
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• 2006

Three-dimensional neutron flux and fluence of Kori Unit 3 were evaluated using the synthesis technique described in Regulatory Guide 1.190 for all reactor geometry. For this purpose DORT neutron transport calculations from Cycle 1 to Cycle 15 were performed using BUGLE-96 cross-section library. The calculated flux and fluence were validated by comparing the calculated reaction rates to the measurement data from the dosimetry sensor set of the $5^{th}$ surveillance capsule withdrawn at the end of cycle 15 of Kori Unit 3. And then the best estimation of the neutron exposures for the reactor vessel beltline region was performed using the least square evaluation. These results can be used in the assessment of the state of embrittlement of Kori Unit 3 pressure vessel.

• 한국정밀공학회지
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• 제16권11호
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• pp.166-173
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• 1999

Al forged parts are many cases with rib-web section which is difficult to manufacture precisely. Therefore, process conditions must be optimized for precision forging of Al alloys. In this study, various process parameters such as die design, lubricant, ram speed, forging temperature have been investigated using the experiment, upper bound theory and F.E.M. simulation to develop the precision forging technology for rib-web shape component. When lubricant is applied to both material and die, shear friction factor is 0.1 which shows best effect of lubricant. It is specific corner radius of die that minimized forging load regarding process conditions, especially according to the ratio of the width of rib and web. In conclusion, optimum corner radius is 2~3mm when the width of rib and web is 3mm and 20mm respectively.

• Nuclear Engineering and Technology
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• 제34권4호
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• pp.269-285
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• 2002

Water heat transfer experiments were carried out in a uniformly heated annulus with a wide range of pressure conditions. The local heat transfer coefficients for saturated water (low boiling have been measured just before the occurrence of the critical heat flux (CHF) along the length of the heated section. The trends of the measured heat transfer coefficients were quite different from the conventional understanding for the heat transfer of saturated flow boiling. This discrepancy was explained from the nucleate boiling in the liquid film of annular flow under high heat flux conditions. The well-known correlations were compared with the measured heat transfer coefficients. The Shah and Kandlikar correlations gave better prediction than the Chen correlation. However, the modified Chen correlation proposed in the present work showed the best agreement with the present data among correlations examined .

• Journal of information and communication convergence engineering
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• 제19권3호
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• pp.148-154
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• 2021

With the advent of context-aware computing, many attempts were made to understand emotions. Among these various attempts, Speech Emotion Recognition (SER) is a method of recognizing the speaker's emotions through speech information. The SER is successful in selecting distinctive 'features' and 'classifying' them in an appropriate way. In this paper, the performances of SER using neural network models (e.g., fully connected network (FCN), convolutional neural network (CNN)) with Mel-Frequency Cepstral Coefficients (MFCC) are examined in terms of the accuracy and distribution of emotion recognition. For Ryerson Audio-Visual Database of Emotional Speech and Song (RAVDESS) dataset, by tuning model parameters, a two-dimensional Convolutional Neural Network (2D-CNN) model with MFCC showed the best performance with an average accuracy of 88.54% for 5 emotions, anger, happiness, calm, fear, and sadness, of men and women. In addition, by examining the distribution of emotion recognition accuracies for neural network models, the 2D-CNN with MFCC can expect an overall accuracy of 75% or more.