• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.73-78
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• 2003

Ultrasonic measurement is one of important technologies in the lift-time maintenance of nuclear poler plant. Ultrasonic inspection system is consisted of the operator, equipment and procedure. The reliability of ultrasonic inspection system is affected by its ability. The performance demonstration round robin was conducted to quantify the capability of ultrasonic inspection for in-service. The small number of teams who employed procedures that met or exceeded ASME Sec. XI Code requirements detected the piping of nuclear power plant with various cracks to evaluate the capability of detection and sizing. In this paper, the statistical reliability assessment of ultrasonic nondestructive inspection data using Monte Carlo simulation is presented. The results of the probability of detection (POD) analysis using Monte Carlo simulation are compared to these of logistic probability model. In these results, Monte Carlo simulation was found to be very useful to the reliability assessment f3r the small hit/miss data sets.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.812-819
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• 1996

This study was performed to quantify microscopically morphological characteristics of cotton fiber to identify parameters for quality evaluation using image analysis . The image of each fiber was captured by a Pc-based color imaging system using a conventional microscope. Ends of individual cotton fibers were glued on a microscope slide without any tension or straightening. A modified watershed technique was implemented to identify individual convolution segments, which were defined as sections of the fiber bordered by two neighboring convolutions. Length, area and perimeter of each convolution segment were measured directly from the image . Average width, shape factor and number of convolution segments in mm were calculated from the measured parameters. The performance of the image analysis algorithm was compared with visual varieties of cotton . The image analysis results agreed with visual inspection in 89.6% of the tested images.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.3
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• pp.139-150
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• 2000

Although a number of neck injuries are generated, the data which quantify the kinematic response of the human head and cervical spine in low-speed rear-end automobile collisions is very limited. On this problem, just few in vitro experimental research or some experimental research using dummy on neck injury by rear-end collision was conducted, thus systematic research is requested on full scale injury mechanism. An occupant model for the response of the occupant subject to rear-end collision using commercial dynamics package DADS was developed. Developed model shows more close agreement with the experimental data compared with the MADYMO simulation results for the cases of ${\delta}V=16$ kph in sled test. For the case of ${\delta}V=8$ kph and 33.5 kph with production seat, model also shows its reliable response compared with experimental results using Hybrid III and Hybird III with RID.

• Korean System Dynamics Review
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• v.7 no.2
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• pp.215-226
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• 2006

A conceptual system dynamics model is developed to represent the dynamic mechanism between the number of hepatitis B virus and the defense system of the body. The simulation results shows that the model behaves within the reasonable ranges. The developed conceptual model is a first attempt to quantify the dynamic mechanisms of the hepatitis B virus, where only feedback structures are considered without bio-organism data. The next step would be to incorporate the model with bio-organism theory and to carry out case studies to identify personal characteristics. Since the current model is a conceptual model where quantitative results are not based on the sound background, the usage is limited only within the qualitative basis. It could be a effective educational tool for the patients. It also shows what-to-do lists in order to be used for forecast purposes.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.721-725
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• 2004

Multiple-count problem is occurred when rectangle objects span across several buckets. The Cumulative Density (CD) histogram is a technique which solves multiple-count problem by keeping four sub-histograms corresponding to the four points of rectangle. Although it provides exact results with constant response time, there is still a considerable issue. Since it is based on a query window which aligns with a given grid, a number of errors may be occurred when it is applied to real applications. In this paper, we proposed selectivity estimation techniques using the generalized cumulative density histogram based on two probabilistic models: (1) probabilistic model which considers the query window area ratio, (2) probabilistic model which considers intersection area between a given grid and objects. In order to evaluate the proposed methods, we experimented with real dataset and experimental results showed that the proposed technique was superior to the existing selectivity estimation techniques. The proposed techniques can be used to accurately quantify the selectivity of the spatial range query on rectangle objects.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.538-543
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• 2003

Perforated wall has long been employed to control a variety of flow phenomena. It has been, in general, characterized by a porosity of the perforated wall. However, this porosity value does not take account of the number and detailed shape of porous holes, but is defined by only the ratio of the perforated area to total wall surface area. In order to quantify the porous wall effects on the flow control performance, an effective porosity should be known with the detailed flow properties inside the porous holes. In the present study, a theoretical analysis using a small disturbance method is performed to investigate detailed flow information through porous hole and a computational work is also carried out using the two-dimensional, compressible Navier-Stokes equations. Both the results are compared with existing experimental data. The gasdynamical porosity is defined to elucidate the effect of perforated wall.

• Journal of Korea Water Resources Association
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• v.56 no.11
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• pp.823-835
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• 2023

Recently, due to the increase in abnormal climate, rainfall intensity is increasing and drought periods are continuing. These environmental changes lead to prolonged drought conditions and difficulties in real-time recognition. In general, drought can be judged by the amount of precipitation and the number of days without rainfall. In determining the impact of drought, it is divided into meteorological drought, agricultural drought, and hydrological drought and evaluation is made using the drought index, but environmental drought evaluation is insufficient. The river water quality managed through the total water pollution cap system is vulnerable to the effects of such drought. In this study, we aim to determine the drought impact on river water quality and quantify the impact of prolonged drought on water quality. The impact of rain-free days and accumulated precipitation on river water quality was quantitatively evaluated. The Load Duration Curve (LDC), which is used to evaluate the water quality of rivers, was used to evaluate water pollution occurring at specific times. It has been observed that when the number of consecutive rainless days exceeds 14 days, the target water quality in the mid-basin is exceeded in over 60% of cases. The cumulative rainfall is set at 28 days as the criteria, with an annual average rainfall of 3%, which is 32.1 mm or less. It has been noted that changes in water quality in rivers occur when there are 14 or more rainless days and the cumulative rainfall over 28 days is 32.1 mm or less in the Gamcheon Mid-basin. Based on the results of this study, it aims to quantify the drought impact and contribute to the development of a drought water quality index for future environmental droughts.

• Journal of Nutrition and Health
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• v.54 no.2
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• pp.129-138
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• 2021

To set the estimated energy requirement (EER) in Dietary Reference Intakes for Koreans (KDRI), we need the coefficient by physical activity stage, as determined by the physical activity level(PAL). Thus, there has been demand for a tool to calculate PAL based on the physical activity diary. This study was undertaken to develop a physical activity (PA) classification table for Koreans, using the 2011 Compendium of physical activities in the United States. The PA classification table for Koreans contains 262 codes, and values of the metabolic equivalent of task (MET) for specific activities. Of these, 243 PAs which do not have Korean specific data or information, were selected from the 2011 Compendium of PAs that originated in the United States; another 19 PAs were selected from the previous research data of Koreans. The PA classification table is codified to facilitate the selection of energy values corresponding to each PA. The code for each PA consists of a single letter alphabet (activity category) and four numeric codes that display the activity type (2 digit number), activity intensity (1 digit number), and specific activities (1 digit number). In addition, the intensity (sedentary behavior, low, middle and high) of specific PA and its rate of energy expenditure in MET are presented together. The activity categories are divided into 4 areas: Daily Activity (A), Movement (B), Occupation (C), and Exercise and Sports (D). The developed PA classification table can be applied to quantify the energy cost of PA for adults in research or practice, and to assess energy expenditure and physical activity levels based on self-reported PA.

• International Journal of Industrial Entomology and Biomaterials
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• v.4 no.2
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• pp.137-141
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• 2002

An experimental study was undertaken to quantify the effects of insect hormones on the replication of nucleopolyhedrovirus (NPV). The results demonstrated that TCID/ sub 50/ at 72 h post-infection (hpi) rose systematically from 0.55$\times$10$^{8}$ /m1, for untreated cells, up to 1.67$\times$10$^{8}$ / ml at 3$\mu$g/ml, then dropped down to 1.45$\times$10$^{8}$ /m1 at 4 $\mu$g/ml, by adding ecdysone to the culture medium for Bm-N cells infected with a wild-type Bambyx mori. nucleopolyhedrovirus (BmNPV). The optimum enhancement of about 3 times on budded virus (BV) titer at 72 hpi was given at 3 $\mu$g/ml of ecdysone. While the polyhedra number had no obvious variation within the range of concentrations from 0 to 4 $\mu$g/ml. By addition of juvenile hormone analogue (JHA) into the media with this concentration range, the BmNPV TCID/ sub 50/ and polyhedra number at 72 hpi did not show significant changes. Also, the addition of either 3 $\mu$g/ml of ecdysone or 3 $\mu$g/ml of JHA to the culture media did not appear to affect the TCID/ sub 50/ and polyhedra number significantly in infected Sf-21 cells with the autographa californica nucleopolyhedrovirus (AcMNPV).

• Asia-Pacific Journal of Business
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• v.12 no.3
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• pp.51-69
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• 2021

Purpose - Based on literature studies of movie reviews and movie ratings, this study raised two research questions on the contents of online word of mouth and the number of movie screens as mediator variables. Research question 1 wanted to figure out which topics of word groups had a positive or negative impact on movie ratings. Research question 2 tried to identify the role of the number of movie screens between movie ratings and box office outcomes. Design/methodology/approach - Through R program, this study collected about 82,000 movie reviews and movie ratings posted on Naver's movie website to examine the role of online word of mouths and movie screen counts in 10 movies that were considered commercially unsuccessful with fewer than 2 million viewers despite securing about 1,000 movie screens. To confirm research question 1, topic modeling, a text mining technique, was conducted on movie reviews. In addition, this study linked the movie ratings posted on Naver with information of KOBIS by date, to identify the research question 2. Findings - Through topic modeling, 5 topics were identified. Topics found in this study were largely organized into two groups, the content of the movie (topic 1, 2, 3) and the evaluation of the movie (topics 4, 5). When analyzing the relationship between movie reviews and movie ratings with 5 mediators identified in topic modeling to probe research question 1, the topic word groups related to topic 2, 3 and 5 appeared having a negative effect on the netizen's movie ratings. In addition, by connecting two secondary data by date, analysis for research question 2 was implemented. The outcomes showed that the causal relationship between movie ratings and audience numbers was mediated by the number of movie screens. Research implications or Originality - The results suggested that the information presented in text format was harder to quantify than the information provided in scores, but if content information could be digitalized through text mining techniques, it could become variable and be analyzed to identify causality with other variables. The outcomes in research question 2 showed that movie ratings had a direct impact on the number of viewers, but also had indirect effects through changes in the number of movie screens. An interesting point is that the direct effect of movie ratings on the number of viewers is found in most American films released in Korea.