• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 가을 학술발표회 논문집
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• pp.131-137
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• 1996

To perform condition monitoring of P.C. Box girder bridge under ambient traffic, dynamic characteristics were identified using the results of load test an analysis. It was found that natural frequencies obtained from the measured acceleration data for the forced vibration part and free vibration part were nearly identical. Thus it can be concluded that dynamic parameters are properly determined under ambient traffic condition. Finite element model for analysis was calibrated using measured frequencies. Change of dynamic characteristics were predicted through analysis of the established finite element model with anticipated change.

• 한국도로학회논문집
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• 제15권6호
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• pp.93-101
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• 2013

PURPOSES : The rumble strip installed at the highway near the tollgate has the purpose to reduce the vehicle velocity or prevent sleepiness by awakening people to the danger. These rumble strip has different vibration decibel from the rumble strip shapes, resulting in some fatigue damage to human because a driver suffers from a lot of stress and displeasure. In this connection, the objective of this paper is to analyze the vibration decibel perceived by a driver in the vehicle under some conditions. METHODS : The vibration decibel conveyed from the tire can be analyzed. The frequency analysis methods were used according to DFT (Discrete Fourier Transform) analysis, FFT (Fast Fourier Transform) analysis, CPB (Constant Percentage Bandwidth) analysis. But the frequency analysis method in this paper is the 1/24 OCT(Octave) band analysis because of the convenience of the analysis and the overall vibration amplitude along the frequency. RESULTS : By using the results of the vibration decibel after analyzing the 1/24 OCT band analysis, these results can be compared from some conditions (e.g., rumble strip shape, uniform velocity of a vehicle, road condition, mass of a vehicle). As a result, the numerical values of decibel are not directly proportional to the vehicle velocity. CONCLUSIONS : At the condition that a vehicle is passing by the rumble strip, the value of a vibration decibel at the rumble strip of the cylinder shape is smaller than the rumble strip of rectangular shape regardless of the rumble strip depth and width. At the mass condition, the more a vehicle is massive, the more the vibration decibel increases. At the road condition, the vibration decibel at the wet road is smaller than the value at dry road condition.

• 비파괴검사학회지
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• 제30권6호
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• pp.558-563
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• 2010

In this paper, the novel approach for the fault diagnosis of the bearing equipped with rotational mechanical facilities was studied. As research works, by applying the ball bearing used extensively in many industrial fields, experiments were conducted in order to propose the new prognostic method about the condition monitoring for the rotational bodies based on the condition analysis of infrared thermography. Also, by using the vibration spectrum analysis, the real time monitoring was performed. As results, it was confirmed that infrared thermography method could be adapted into monitor and diagnose the fault for bearing by evaluating quantitatively and qualitatively the temperature characteristics according to the condition of the ball bearing.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제27회 춘계학술대회
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• pp.212-217
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• 1998

Reynolds equation, which describes behavior of fluid film in journal bearing, basically satisfies mass conservation. But, boundary conditions usually used with this equation, e.g. half Sommerfeld or Reynolds boundary conditions, cannot fulfill this natural law of conservation. In the case of connecting rod bearing, where applied load is dynamic and its magnitude is relatively large, such unrealistic boundary conditions have serious influence on calculation results, especially on lubricant flow rate or power dissipation which are important parameters in thermal analysis. Another important factor in the analysis of connecting rod bearing is elastic deformation of bearing support structure which is relatively flexible. In this paper, EHL analysis of connecting rod beating is performed using mass-conserving boundary condition. Elastic deformation of bearing support structure and application of mass-conserving boundary condition have significant effects on the performances of connecting rod bearing.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1998년도 가을 학술발표회 논문집
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• pp.61-68
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• 1998

It has become important to evaluate the qualitive reliability and condition assessment of existing structural systems in order to establish a rational program for repair and maintenance. Since most of if existing structural system may suffer from defect corrosion and damage, it is necessary to account for their effects in fuzzy reliability analysis, In this paper, an attempt is made to develope a reliability analysis for damaged structural systems using failure possibility theory. Damage state is specified in terms of linguistic valiables using natural language information and numerical information, which are defined by fuzzy sets. Using a subjective condition index of failure possibility and information of the damage state is introduced into the calculation of failure probability. The subjective condition index of quantitative and qualitative analysis method is newly proposed based on the fuzzy set operations, namely logical product, drastic product, logical sum and drastic sum

• 한국정보기술학회 영문논문지
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• 제8권2호
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• pp.47-58
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• 2018

In this paper, we propose a method for skin condition analysis using a camera module embedded in a smartphone without a separate skin diagnosis device. The type of skin disease detected in facial image taken by smartphone is acne, pigmentation, blemish and flush. Face features and regions were detected using Haar features, and skin regions were detected using YCbCr and HSV color models. Acne and flush were extracted by setting the range of a component image hue, and pigmentation was calculated by calculating the factor between the minimum and maximum value of the corresponding skin pixel in the component image R. Blemish was detected on the basis of adaptive thresholds in gray scale level images. As a result of the experiment, the proposed skin condition analysis showed that skin diseases of acne, pigmentation, blemish and flush were effectively detected.

• 한국정밀공학회지
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• 제14권5호
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• pp.143-149
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• 1997

This paper was undertaken to do image analysis of wear debris on operating condition of the lubricated moving surfaces. This lubricating wear test was performed under different experimental conditions using the wear test device was made in our laboratory and wear testing specimen of the pin on dist type was rubbed in paraffine series base oil, by materials, varying applied load, sliding distance. The four shape parameters (50% volumetric diameter, aspect, roundness and reflectivity) to describe wear debris have been developed and are outlined in the paper. A system using such techniques promises to obviate the need for subjective, human interpretation of particle morphology for machine condition monitoring, this to overcome many of the difficulties with current methods and facilitating wider use of wear particle analysis in machine condition monitouing.

• 한국환경과학회지
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• 제15권3호
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• pp.261-269
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• 2006

In this study, an optimization technique was developed from the application of allocation rule. The results obtained from the water supply analysis and reliability indices analysis of Andong dam and Imha dam which are consist of parallel reservoir system are summarized as the followings; Allocation rule(C) is effective technique at the parallel reservoir system because results of the water supply analysis, storage analysis and reliability indices analysis is calculated reasonable results. Also, reliability indices analysis results are not sufficient occurrence based reliability or quantity based reliability. Thus reliability indices analysis are need as occurrence based reliability, quantity based reliability vulnerability, resilience, average water supply deficits and average storage. And water supply condition is better varying water supply condition than constant water supply condition.

• 대한치과기공학회지
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• 제33권4호
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• pp.467-478
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• 2011

Purpose: The purpose of this study was to analyze dental technician's job environment and health condition level and to examine its correlation. Methods: 250 dental technicians in Seoul, Incheon, and Jeonbuk area were selected. Survey was carried out from October 11, 2010 to November 25, 2010 by using self-administered questionnaire. As for the tools for this study, the structured questionnaire was used with its proven reliability and feasibility, and the questionnaire consisted of total 49 questions which included general attribute of subjects(14 questions), job Environment(13 questions) and health condition(22 questions). The data analysis was processed by computerized system with SPSS Win 17.0. Statistical analysis techniques included frequency, percentage, T-test, One-way ANOVA analysis and regression analysis. Results: As a result of analyzing the research subjects' job environment level, there was significant difference in the item of gender, working hours a day(Hour), healthy condition, job satisfaction level with dental technician, plan for task continuity in dental technician(P<0.05). The average in the job environment was indicated to be high with 2.85. As a result of analyzing the research subjects' health condition level, there was significant difference in the item of gender, task field, working hours a day(Hour), healthy condition, job satisfaction level, plan for task continuity(P<0.05). The average in the self health recognition was indicated to be high with 2.83. Conclusion: Correlation between job environment and health condition, all of variables were indicated to have reverse correlation, thereby having been shown that the worse job environment leads to the more physical subjective symptoms.

• 융합정보논문지
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• 제11권5호
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• pp.267-275
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• 2021

피부상태는 미용적인 측면에서 중요한 관심사이다. 본 연구는 뷰티산업종사자들이 육안관찰 또는 스마트폰 등으로 촬영된 피부상태 이미지를 통하여 할 수 있는 개략적 피부상태 분석방법에 대하여 고찰하였다. 학술연구정보서비스(RISS)에서 '피부상태'와 관련된 키워드로 검색되는 학위논문과 학술논문 중 주관적 평가와 객관적 평가를 병행한 논문, 육안확인이 가능한 요인들과의 상관관계를 도출한 논문을 선별하였고, 주관적인 피부상태와 객관적 피부측정결과가 일치하는 요인과 피부표면에서 육안확인이 가능한 요인과의 관계를 조사하였다. 연구결과, 주관적·객관적 평가가 일치하는 가장 적합한 요인은 '유분량'이었고, 이는 피부표면에서 육안확인이 가능한 '모공', '피부결', '홍반'과 유의미한 상관관계가 있는 것으로 나타났다. 이를 이용하여 개략적인 피부상태 분석이 가능할 것으로 사료된다.