• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.128-134
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• 2016

Estimating the repair and reinforcement (R&R) costs for each bridge member is essential for managing the life cycle of a bridge using a bridge management system (BMS). Representative members of a bridge were defined in this study, and detailed and representative R&R methods for each one were drawn in order to develop a systematic maintenance cost model that is applicable to the BMS. The unit cost for each detailed R&R method was established using the standard of estimate and historical cost data, and a systematic procedure is presented using an integration program to enable easy renewal of the R&R unit cost. Also, the average unit cost of the representative R&R methods was calculated in the form of a weighted average by considering the unit cost and application frequency of each detained R&R method. The appropriateness of the drawn average unit cost was reviewed by comparing and verifying it with the previous historical unit cost. The suggested average R&R unit cost can be used to review the validity of the required budget or the appropriateness of the R&R performance cost in the stage to establish the bridge maintenance plan. The results of this study are expected to improve the reliability of maintenance cost information and the rationality of decision making.

• Journal of Korean Clinical Health Science
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• v.5 no.1
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• pp.790-802
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• 2017

Purpose. This study was designed to analyze recent trends in Children Art Therapy Program Intervention research in Korea and suggest future research directions in this area. Methods. Studies(29) selected from http://www.riss4u.net for last 15 year were used. They were analyzed by publication type, field and design of the study, study participants and outcome variables used in intervention studies. Results. 1. As for academic field, there are 15 art therapy academic journals(51.72%), which made up the largest proportion. 2. As for subjects of the study, there are 17 articles of Elementary (58.6%) education, which made up the largest proportion. As for the subjects of sex, 8 articles (27.59%) are for male students, 7 (24.14%) articles are for female students and 14 articles (48.28.%) are for both male and female students. 3. As for 7 articles of Art therapy(24.14%), 7 articles of Group Art therapy (24.14%) made up the largest proporton 4. As for the intervention study method according to the subjects of suicide intervention program, there are 15 articles of monoclonal Pre and post design (51.72%),which made up the largest proportion. 5. As for the sample size, there were 16.79 persons in the treatment group on average, 13.28 persons in the control group have average and the total persons were 10 on average. The treatment period was 12 weeks on average and the average number of treatment times was 18. The places of treatment were 3 schools (10.38%), which made up the largest proportion. 19. The results of the experimental study support the research hypothesis of all 29 programs. Conclusions. As the above, the studies on the art therapy intervention program for children are increasing but the subjects are overly weighted toward elementary school students. Although the content of the art therapy intervention program was varied, it was found that the development of the program using various art media which can induce the motivation of the child was lacking. In addition, the place of experimental mediation was concentrated on psychology center as 12(41.38%), indicating that there are not enough places to connect with community organizations such as schools and hospitals. The variables of experimental study were focused on psychological variables and it was found that there were insufficient application of various variables including coping method, social support, and physiological variables.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.9
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• pp.1-9
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• 2011

In this paper, we propose an efficient method to create clusters of geographically distributed base stations which cooperatively transmit signals in cellular mobile communication systems. The proposed method utilizes a sequential selection approach to choose candidate base stations which can provide maximum weighted sum-rate gain when they participate in the cooperative transmission with the existing cluster. In particular, the proposed method limits the maximum number of base stations in a cluster by considering the system operational and implementation complexities. Moreover, the combinations of clusters dynamically change along with variations of channel environments. Through computer simulations, performance of the proposed method is verified by comparing with the non-cooperative transmission method and the static clustering method. Numerical result shows that the proposed sequential selection based clustering method is especially advantageous for the performance improvement of lower percentile users in terms of average throughput, and thus the proposed method can effectively improve the fairness among users.

• The Journal of Engineering Geology
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• v.24 no.1
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• pp.39-52
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• 2014

Limestone caves that consist of main passages and branches are formed by a variety of processes, and have the characteristic of developing with a preferred orientation controlled by discontinuities such as bedding, joints, and faults around the cave. However, it is difficult to analyze a representative orientation from various orientations. To interpret the overall development orientation of limestone caves, this study proposes new development orientation analysis methods, termed the Average Span Ratio Method (ASRM) and the Individual Development Ratio Method (IDRM), using the weighting of persistence. Nine limestone caves in Korea were randomly selected for testing the new methods. The methods show a stronger development orientation for limestone caves than that obtained by traditional methods, which consider only the distribution of development orientations. Based on an analysis of the relationship between the average span and the dip angle of bedding, it is confirmed that shallowly dipping bedding is a major contributor to the expansion of span in limestone caves. In addition, using scan-line survey data acquired in the field, we perform an RMR analysis of stability of the ground around limestone caves.

• KIPS Transactions on Software and Data Engineering
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• v.7 no.9
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• pp.351-360
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• 2018

The LWR (Locally Weighted Regression) model, which is traditionally a lazy learning model, is designed to obtain the solution of the prediction according to the input variable, the query point, and it is a kind of the regression equation in the short interval obtained as a result of the learning that gives a higher weight value closer to the query point. We study on an incremental ensemble learning approach for LWR, a form of lazy learning and memory-based learning. The proposed incremental ensemble learning method of LWR is to sequentially generate and integrate LWR models over time using a genetic algorithm to obtain a solution of a specific query point. The weaknesses of existing LWR models are that multiple LWR models can be generated based on the indicator function and data sample selection, and the quality of the predictions can also vary depending on this model. However, no research has been conducted to solve the problem of selection or combination of multiple LWR models. In this study, after generating the initial LWR model according to the indicator function and the sample data set, we iterate evolution learning process to obtain the proper indicator function and assess the LWR models applied to the other sample data sets to overcome the data set bias. We adopt Eager learning method to generate and store LWR model gradually when data is generated for all sections. In order to obtain a prediction solution at a specific point in time, an LWR model is generated based on newly generated data within a predetermined interval and then combined with existing LWR models in a section using a genetic algorithm. The proposed method shows better results than the method of selecting multiple LWR models using the simple average method. The results of this study are compared with the predicted results using multiple regression analysis by applying the real data such as the amount of traffic per hour in a specific area and hourly sales of a resting place of the highway, etc.

• Korean Journal of Community Nutrition
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• v.1 no.3
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• pp.376-394
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• 1996

This study evaluated the reproducibility and validity of the self-administered semiquantitative food frequency questionnaire used in a large prospective cohort study(Korean Cancer Research Survey) in middle-aged men. The questionnaire was administered twice at an interval of approximately two years(December, 1992-January, 1995), and four or five 24-hour recalls for each subject were collected at intervals of approximately three months. The results were as follows; 1) Although the distributions of the data estimated by the questionnaire were somewhat wider, the mean nutrient intakes of group estimated by our questionnaires and the multiple 24-hour recalls were roughly comparable. 2) The reproducibility determined by correlation of absolute(unadjusted nutrient intake) and calorie adjusted nutrient intakes from two semiquantitative food frequency questionnaires were more than 0.5, and the weighted kappa values were more than 0.4. 3) The Pearson correlation coefficients between unadjusted nutrient intakes values were average 0.40 on the average(Ca, 0.13-Carbohydrate, 0.58) at the first questionnaire vs. 24-hour recalls, and 0.28 at the second questionnaire vs. 24-hour recalls. The spearman rank order correlation coefficients were similar. When energy intake was adjusted, there was a slight reduction : 0.28 at the second questionnaire, 0.25 average on the second. In order to correct the measurement error of 24-hour recall data, the deattenuated correlation coefficient was calculated. It averaged 0.53 on the first questionnaire, 0.37 on the second questionnaire for unadjusted nutrient intake. for calorie-adjusted nutrient intake, it averaged 0.44 on the first questionnaire, 0.37 on the second questionnarie. 4) There was lower agreement(k<0.4) between the questionnaries and the 24-hour recalls. And the subjects classified in the same quartile by 24-hour recalls and first questionnaire were average 37$\%$(energy-adjusted values) and 40$\%$(unadjusted values) on the average. More than k10$\%$(average) of subjects were in the extreme quartile of the questionnarie and 24-hour recall method. But 8.2$\%$(average) of subjects classified in the lowest quartile of unadjusted nutrient intake level by the 24-hour recalls were in the highest quartile by the first questionnaire. These data indicate that our self-administered semiquantitative food frequency questionnarie is reproducible. Correlation coefficients comparing nutrient intakes measured by two different dietary assessment methods were less than 0.5. The validity of our questionnarie is not high enough.

• Journal of Korean Society for Geospatial Information Science
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• v.12 no.1 s.28
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• pp.39-44
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• 2004

The SCS-CN method was known to have difficulties to the applied to the mountainous area like Korean river basins. This study focused to develop a distributed SCS-CN method considering river basin slopes from GIS data. For the purpose, the method was applied to Sulma river and compared with area weighted average method and distributed SCS-CN method using GIS. According to the results, SCS-CN method considering river basin slopes provided better effects on the estimating effective rainfall on the other methods. The necessity of the generalization of the results to the other rivers was discussed.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.4
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• pp.342-352
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• 2020

Objectives: The characteristics of research workers are different from those working in the manufacturing industry. Furthermore, the reagents used change according to the research due to the characteristics of the laboratory, and the amounts used vary. In addition, since the working time changes almost every day, it is difficult to adjust the time according to exposure standards. There are also difficulties in setting standards as in the manufacturing industry since laboratory environments and the types of experiments performed are all different. For these reasons, the measurement of the working environment of research workers is not realistically carried out within the legal framework, there is a concern that the accuracy of measurement results may be degraded, and there are difficulties in securing data. The exposure evaluation based on an eight-hour time-weighted average used for measuring the working environment to be studied in this study may not be appropriate, but it was judged and consequently applied as the most suitable method among the recognized test methods. Methods: The investigation of the use of chemical substances in the research laboratory, which is the subject of this study, was conducted in the order of carrying out work environment measurement, sample analysis, and result analysis. In the case of the use of chemical substances, after organizing the substances to be measured in the working environment, the research workers were asked to write down the status, frequency, and period of use. Work environment measurement and sample analysis were conducted by a recognized test method, and the results were compared with the exposure standards (TWA: time weighted average value) for chemical substances and physical factors. Results: For the substances subject to work environment measurement, the department of chemical engineering was the most exposed, followed by the department of chemistry. This can lead to exposure to a variety of chemicals in departmental laboratories that primarily deal with chemicals, including acetone, hydrogen peroxide, nitric acid, sodium hydroxide, and normal hexane. Hydrogen chloride was measured higher than the average level of domestic work environment measurements. This can suggest that researchers in research activities should also be managed within the work environment measurement system. As a result of a comparison between the professional science and technology service industry and the education service industry, which are the most similar business types to university research laboratories among the domestic work environment measurements provided by the Korea Safety and Health Agency, acetone, dichloromethane, hydrogen peroxide, sodium hydroxide, nitric acid, normal hexane, and hydrogen chloride are items that appear higher than the average level. This can also be expressed as a basis for supporting management within the work environment measurement system. Conclusions: In the case of research activity workers' work environment measurement and management, specific details can be presented as follows. When changing projects and research, work environment measurement is carried out, and work environment measurement targets and methods are determined by the measurement and analysis method determined by the Ministry of Employment and Labor. The measurement results and exposure standards apply exposure standards for chemical substances and physical factors by the Ministry of Employment and Labor. Implementation costs include safety management expenses and submission of improvement plans when exposure standards are exceeded. The results of this study were presented only for the measurement of the working environment among the minimum health management measures for research workers, but it is necessary to prepare a system to improve the level of safety and health.

• Journal of Korea Water Resources Association
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• v.36 no.4
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• pp.521-531
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• 2003

Pollutant load to Yongdam Reservoir considering rainfall effect is estimated using data collected during dry and wet days between Dec 1998 and Oct. 1999. Limit of significant rainfall was assumed to be as 10 mm/day and numbers of days of significant rainfall for each month were counted using 10 years of meteorological data of the study area. Water quality input concentrations were estimated by taking weighted averages of concentrations in dry and wet days in each month. The resulting concentrations were used as inputs for water quality modeling of Yongdam Reservoir. When rainfall effect was included average reservoir concentrations of BOD, TN and TP were increased by 70％, 5％ and 27％, respectively Considering the fact that Korea is under the significant influence of monsoon effect during the summer, it should be important to include rainfall effect in estimating pollutant input to receiving waters. This method is expected to increase reliability of annual water quality modeling results by providing realistic input data.

• Annals of Occupational and Environmental Medicine
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• v.34
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• pp.7.1-7.10
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• 2022

Background: Occupational skin diseases are skin conditions that occur or worsen in relation to work and known to be the second most common type of occupational disease affecting individuals in the United States. In Korea, epidemiological reports related to occupational skin diseases are rare. But, no cases of occupational contact dermatitis caused by welding and grinding work have been reported previously. Case presentation: Nine male workers working in the production department for liquefied natural gas (LNG) ships in Ulsan complained of erythematous papules/patches and itching in various areas of the body after welding and grinding work. The work environment monitoring report revealed that the amount of nickel dust exceeded the time weighted average (TWA) and poor local ventilation status. Based on the symptoms and the overall results of surveys, several tests, and work environment monitoring report, the 2 workers who had positive patch-test reactions to nickel were diagnosed with nickel dust-induced allergic contact dermatitis. The other 7 workers were diagnosed that there was a high probability that they had nickel dust-induced irritant contact dermatitis. The 2 workers who had nickel dust-induced allergic contact dermatitis were recommended to switch their jobs. Conclusions: Nickel is one of the most common cause of allergic contact dermatitis. In this case, the dust was assumed to be created by welding work with a high nickel content new welding rod and subsequent grinding work, and the concentration of this dust exceeded the time weighted average. Thus, it is thought that the nickel dust may have caused contact dermatitis through continuous contact with the workers' exposed skin in a poorly ventilated space. Currently, several domestic shipbuilding companies are manufacturing LNG tankers using a new construction method. Consequently, it is highly likely that similar cases will occur in the future, which makes this case report meaningful.