• 제목/요약/키워드: industrial difference

검색결과 3,451건 처리시간 0.03초

ANALYSIS OF A ONE-DIMENSIONAL FIN USING THE ANALYTIC METHOD AND THE FINITE DIFFERENCE METHOD

  • Han, Young-Min;Cho, Joo-Suk;Kang, Hyung-Suk
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • 제9권1호
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    • pp.91-98
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    • 2005
  • The straight rectangular fin is analyzed using the one-dimensional analytic method and the finite difference method. For the finite difference method, the numbers of nodes vary from 20 to 100. The relative errors of heat loss and temperature between the analytic method and the finite difference method are represented as a function of Biot Number and dimensionless fin length. One of the results shows that the relative error between the analytic method and the finite difference method decreases as the numbers of nodes for finite difference method increase.

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JND를 이용한 휴대폰의 최적 진동 주파수 설계 (JND-based Mobile Phone Optimal Vibration Frequency)

  • 이봉왕;박현호;명노해
    • 대한산업공학회지
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    • 제30권1호
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    • pp.27-35
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    • 2004
  • A study was conducted to investigate an optimal vibration frequency for mobile phones with just noticeable difference(JND). The just noticeable difference, Weber's law, is the minimum amount by which stimulus intensity must be changed in order to produce a noticeable variation in sensory experience. In order to find the optimal vibration frequency, sixteen frequencies ranged from 24Hz to 603Hz were selected. Subjects then wereasked to differentiate a pair of vibration frequencies. For the analysis, the psychometric function to determine the optimal vibration frequency and the logistic regression to validate the determined frequency were used. The results show that the 2nd order polynomial equations were best fitted for the JND psychometric function and the optimal mobile phone vibrations were determined at 140Hz, 151 Hz, and 160Hz. With the ogive-shaped psychometric function developed by the logistic regression, the results of this study was validated that the determined vibration frequencies (140Hz, 151 Hz, and 160Hz) were optimal mobile phone vibration frequencies.

차량도어 조립공차 예측기술 개발 (An Advanced Prediction Technology of Assembly Tolerance for Vehicle Door)

  • 정남용;조진형;오현승;이세재
    • 산업경영시스템학회지
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    • 제41권4호
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    • pp.91-100
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    • 2018
  • The setting of values on door hinge mounting compensation for door assembly tolerance is a constant quality issue in vehicle production. Generally, heuristic methods are used in satisfying appropriate door gap and level difference, flushness to improve quality. However, these methods are influenced by the engineer's skills and working environment and result an increasement of development costs. In order to solve these problems, the system which suggests hinge mounting compensation value using CAE (Computer Aided Engineering) analysis is proposed in this study. A structural analysis model was constructed to predict the door gap and level difference, flushness through CAE based on CAD (Computer Aided Design) data. The deformations of 6-degrees of freedom which can occur in real vehicle doors was considered using a stiffness model which utilize an analysis model. The analysis model was verified using 3D scanning of real vehicle door hinge deformation. Then, system model which applying the structural analysis model suggested the final adjustment amount of the hinge mounting to obtain the target door gap and the level difference by inputting the measured value. The proposed system was validated using the simulation and showed a reliability in vehicle hinge mounting compensation process. This study suggests the possibility of using the CAE analysis for setting values of hinge mounting compensation in actual vehicle production.

A Study on the Difference of Total Grip Strength and Individual Finger Force between Dominant and Non-dominant Hands in Various Grip Spans of Pliers

  • Kong, Yong-Ku;Park, Hyunjoon;Kim, Dujeong;Lee, Taemoon;Roh, Eunyoung;Lee, Seulki;Zhao, Wenbin;Kim, Dae-Min;Kang, Hyun-Sung
    • 대한인간공학회지
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    • 제32권6호
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    • pp.503-509
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    • 2013
  • Objective: The purpose of this study is to analyze the individual finger force between dominant hand and non-dominant hand and to investigate an effect of the individual finger on the total grip strength depending on dominant hand and non-dominant hand. Background: Many studies on the ratio of the grip force between dominant hand and non-dominant hand has been researched. While a 10% rule which is a ratio of the grip force between dominant hand and non-dominant hand has been applied in most studies, studies on the rate of the individual finger force between dominant hand and non-dominant hand have been insufficiently researched. Method: The experiment was preceded with 17 subjects (male, mean 25.8 ages). The individual finger force and total grip strength were measured using pliers being able to change the grip span from 45 to 80mm. Results: The difference of total grip strength between dominant hand and non-dominant hand is following 10% rule. However, the difference of individual finger force between dominant hand and non-dominant hand are not same as the difference of total grip strength. Especially in the case of grip span with 50mm, the differences between total grip strength, index finger, middle finger, ring finger, and little finger were $9.87{\pm}14.80%$, $8.95{\pm}37.17%$, $13.71{\pm}28.27%$, $6.77{\pm}24.35%$, $39.29{\pm}42.46%$, respectively, with p=0.018 of statistical significance. Additionally, the results of regression analysis in 50 and 60mm of grip span showed that the difference in ring finger affected the most to the total grip strength; and the effects followed in order of index finger, middle finger, and little finger. Conclusion: Our study suggests that an effect of individual finger and grip span of pliers have to be considered when explaining the difference of the total grip strength between dominant hand and non-dominant hand. Application: This result is expected to be used for designing ergonomic hand tool.

A Comparison between 3-D Analytical and Finite Difference Method for a Trapezoidal Profile Fin

  • 이성주;강형석
    • 산업기술연구
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    • 제21권A호
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    • pp.41-50
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    • 2001
  • A comparison is made of the temperature distribution and heat loss from a trapezoidal profile fin using two different 3-dimensional methods. These two methods are analytical and finite difference methods. In the finite difference method 78 nodes are used for a fourth of the fin. A trapezoidal profile fin being the height of the fin tip is half of that of the fin base is chosen arbitrarily as the model. One of the results shows that the relative error in the total convection heat loss obtained by using 78 nodes in the finite difference method as compared to the heat conduction through the fin root obtained by analytic method seems to be good (i.e., -3.5%

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A comparative study of nutrient compositions between HongJams prepared from 5 silkworm varieties making white cocoons

  • Nam-Suk, Kim;Sang Kug, Kang;Sung-Wan, Kim;Min Young, Kim;Kee-Young, Kim;Young Ho, Koh
    • International Journal of Industrial Entomology and Biomaterials
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    • 제45권2호
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    • pp.84-92
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    • 2022
  • White-Jade silkworm (previously also known as Baegokjam) variety is the most popular silkworm variety that produces white cocoons. In 2021, the market share of White-Jade variety in Korea is very high, accounting for 88% of the silkworm production. Daebaekjam, Dodamsilkworm, Kumkangjam, and Kumokjam varieties, which have recently been established, make white cocoons like White-Jade. In this study, we found that 5 types of HongJams produced from 5 varieties of silkworms producing white cocoons did not show any severe difference in proximate analysis. The amounts of crude proteins, the most abundant nutrient, were between 71.05 ~ 73.38%, and those of crude lipids were 13.89 ~ 14.69% in 5 types of HongJams. In addition, there was no difference between White-Jade HongJam (WJ) and Daebaekjam HongJam in amino acid compositions. The amount of unsaturated fatty acid was significantly higher in WJ than in the other four types of HongJams, but the omega-6 fatty acids/omega-3 fatty acids ratio was higher in the four types of HongJams. Most of the minerals were higher in four types of HongJams than in WJ, and three heavy metal were not detected in all 5 types of HongJams. Phytochemicals were also most abundant in WJ, but the difference in the amounts were not severe. And pepsin digestibility was the highest for Kumokjam HongJam and the lowest for Dodam-silkworm HongJam, but the difference was not severe. The nutritional component analysis results of this study suggested that four new varieties can be used for producing HongJams, and Daebaekjam can replace White-Jade the most as the protein source.

비대칭무게중심을 지닌 물체 들기 작업시 허리부위 등근육 부하 및 피로 분석 (The Analysis of Low Back Loading and Muscle Fatigue while Lifting an Asymmetric Load)

  • 한승조;김선욱
    • 산업경영시스템학회지
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    • 제35권2호
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    • pp.30-36
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    • 2012
  • This study is aimed to show that an asymmetric load in the frontal plane leads to an increase in low back loading and fatigue in comparison with a symmetric load when workers lift an external weight by investigating previous studies and verifying the phenomenon with an experiment. Ten male subjects are required to lift and hold an given external load at 70cm height during 50sec, then the EMG amplitude and median frequency on bilateral low back muscle groups (Longissimus, Iliocostalis, and Multifidus) are recorded and analyzed. Independent variables are two-level load weight (13kg, 20kg) and three-level LCG (Center, 6.5cm to the right, and 13cm to the right), and dependent variables are EMG amplitude average, difference, and Fatigue Index (FI). Results show that load weight increases significantly amplitude average and FI, but LCG does significantly amplitude difference and FI significantly (P-value < 0.05). Also the correlation coefficient between amplitude difference and FI is over 0.99. These implies that trunk loading should be explained by not EMG amplitude but muscle fatigue aspect since the association between an external load and amplitude is linear, but the relationship between an external load and median frequency as muscle fatigue index is almost exponential.

지니(Gini)의 평균차이를 이용한 공정산포 추정 (On the Estimation of the Process Deviation Based on the Gini's Mean Difference)

  • 남호수;이병근;정현석
    • 산업경영시스템학회지
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    • 제23권58호
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    • pp.113-118
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    • 2000
  • Estimation of the process deviation is an important problem in statistical process control, especially in the control chart, process capability analysis or measurement system analysis. In this paper we suggest the use of the Gini's mean difference for the estimation of the c, the measure of the process deviation through a lots of simulations in various types of distributions. The Gini's mean difference uses the differences of all possible pairs of data. This point will improve the efficiency of estimation. In various classes of distributions, the Gini's mean difference shows good performance, in sense of bias of estimates or mean squared errors.

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보급형 디지털 장비를 이용한 Deco-Film용 PVC의 색차판별에 대한 연구 (A Study on Color Difference Discrimination for PVC Deco-Film using Entry-Level Digital Device)

  • 임호윤;김민수
    • 한국전자거래학회지
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    • 제22권1호
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    • pp.1-13
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    • 2017
  • 스마트폰, 디지털 카메라 및 사무용 스캐너와 같은 보급형 디지털 영상장비가 과거에 비해 매우 개선되었음에도 실제 산업 현장에서 활용되는 경우는 거의 없다. 이것은 산업 현장에서 요구되는 높은 수준의 품질과 성능 때문이지만, 향상된 보급형 장비의 성능이 충분히 기존 산업용 장비를 대신할 만큼 성장했는지에 대해 객관적인 검증은 부족한 상황이다. 만약 보급형 장비가 활용될 수 있는 영역을 실험을 통해 객관적으로 확인할 수 있다면, 기업들은 고가의 산업용 장비 구입에 투자하는 비용을 절감할 수 있을 것이다. 본 연구에서는 PVC(Polyvinyl chloride) 컬러용지의 색차판별에 대한 보급형 디지털 영상장비의 활용가능성을 실험하고자 한다. 스마트폰, 디지털 카메라 및 사무용 스캐너를 색차판별 실험에 사용하여, 사무용 스캐너가 적은 측정오차와 일관된 결과를 보이는 것을 확인하였다. 사무용 스캐너를 실제 산업용 분광색차계와 비교하는 추가 실험을 통해 두 결과의 상관관계가 높다는 것을 확인하였다. 본 연구의 결과를 토대로 색차판별을 위한 적절한 관리기준을 마련한다면 PVC 컬러용지 제작에서 사무용 스캐너가 산업용 분광색차계를 충분히 대신할 수 있을 것으로 기대된다.

Optical Simulation of Multicolor Cholesteric Liquid Crystal Displays Using Finite-Difference Time- Domain (FDTD) Method

  • Ding, J.M.;Ting, C.L.;Lin, Y.R.;Chen, R.D.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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    • pp.1142-1145
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    • 2006
  • The Finite-difference time-domain (FDTD) method is used to directly solve Maxwell's equations, and the techniques required for optical simulation of Bragg reflections of cholesteric liquid crystal (ChLC) displays are introduced in this paper. The simulated results show that the color gamut of a ChLC display can be broadened by using of a circular polarizer on top surface of the ChLC film, and are examined by experiments.

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