• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.6
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• pp.4322-4327
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• 2015

Improper backfill materials and compaction controls under pipelines have become one of the major causes of failure in many sewage pipeline systems. A study on backfill materials and compaction controls has been considered for a long time. However, structural supporters under the pipe were recently concerned because of pipeline repair and maintenance. This paper presents a prefabricated plastic foundation for supporting a sewage pipe system and increasing the performance function of the pipes. Several analytical models for the plastic foundations were investigated using finite-element program, ABAQUS, for checking safety. Comparing with the results of analyses, some of economic design sections based on the sizes of pipe diameters, 600mm, 700 and 600mm, were evaluated. These results could be applied to a pipeline system with a prefabricated plastic foundation with respect to pipe diameters and buried depths.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.6168-6175
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• 2014

Several studies regarding the effects of academic achievement on mental health problems have been conducted in adolescents but not in elementary school students. Therefore, the aim of the current study was to examine the effects of school achievement on depression in Korean elementary school students. The participants were 1,048, 5th to 6th elementary students in Seoul, Korea. The Spearman correlations between school achievement and depression were -0.31 for boys and -0.37 for girls (p<0.001 for both). After controlling for grader, the family economic status and self-esteem, higher achiever group showed a significantly low risk for depression in boys and girls. This study suggests that the lower school achievement is associated with a depressive mood in Korean elementary students. Therefore, students with lower academic performance are a risk group for depression.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.1
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• pp.78-88
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• 2012

Although structural concrete is well known for its good economic efficiency, it has limits of structural performance due to the low tensile strength, for which new structural members utilizing various concrete composite materials have been developed. Steel Fiber-Reinforced Concrete(SFRC) has great tensile strength, which is the one of the excellent composite material to complement the weakness of concrete, and it is also considered as a good alternative to prevent the explosive failure of high strength concrete under fire. Also, prestressed concrete members are of great advantages to long span structures and have greater shear strength compared to conventional reinforced concrete members. In this research, thus, a total of 22 direct shear test specimens were fabricated and tested to understand the shear behavior of Steel Fiber-Reinforced Prestressed Concrete(SFR-PSC) members, in which SFRC members combined with prestressing method. Based on the test results, the constitutive equations of shear behavior at crack interfaces were proposed, which provided good estimation on the shear behavior of the SFR-PSC direct shear test specimens.

• Journal of the Institute of Convergence Signal Processing
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• v.20 no.3
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• pp.138-144
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• 2019

In a modern society, people are concerned seriously about their travel destinations depending on time, economic problem. In this paper, we propose an non-hierarchical clustering based hybrid recommendation using context knowledge. The proposed method is personalized way of recommended knowledge about preferred travel places according to the user's location, place, and weather. Based on 14 attributes from the data collected through the survey, users with similar characteristics are grouped using a non-hierarchical clustering based hybrid recommendation. This makes more accurate recommendation by weighting implicit and explicit data. The users can be recommended a preferred travel destination without spending unnecessary time. The performance evaluation uses accuracy, recall, F-measure. The evaluation result was shown 0.636 accuracy, 0.723 recall, and 0.676 F-measure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.2
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• pp.1083-1088
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• 2014

Recently, due to advances in both imaging technology and ICT, various types of image processing services became available and the application services of these two technologies are diversifying. Recognition of vehicle license plates is used in places where vehicle information is needed such as in parking management. However, existing systems have economic disadvantages like issuing parking tickets and attaching unnecessary equipment. In order to solve these problems, we designed and implemented automatic parking management system through recognition of vehicle license plates by using emguCV that is based on OpenCV. Additionally, we designed improved UI to handle the entire parking management situation which include information such as details of each parking vehicle, parking time and remaining parking spaces without screen movement. This improved UI is implemented with the use of WPF which is the latest technology in user program development. The emguCV used in this paper showed the most optimized performance in Intel based environment. With it, we obtained the result of within 0.5 seconds of recognition processing time and over 90% of recognition rate. Through improved UI, the manager could both simply and intuitively manage the entire system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.8
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• pp.1340-1346
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• 2016

Utilization of Distributed Generations (DGs) using Renewable Energy Sources (RESs) has been constantly increasing as they provide a lot of environmental, economic merits. In spite of these merits, some problems with respect to voltage profile, protection and its coordination system due to reverse power flow could happen. In order to analyze and solve the problems, accurate modeling of DG systems should be preceded as a fundamental research task. In this paper, we present a PhotoVoltaic (PV) generation system which consists of practical PV cells with series and parallel resistor and an inverter for interconnection with a main distribution system. The inverter is based on controllable current source which is capable of controlling power factors, active and reactive powers within a certain limit related to amount of PV generation. To verify performance of the model, a distribution system based on actual data is modeled by using ElectroMagnetic Transient Program (EMTP) software. Computer simulations according to various conditions are also performed and it is shown from simulation results that the model presented is very effective to study DG-related researches.

• International Journal of Highway Engineering
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• v.9 no.3
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• pp.91-100
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• 2007

The most important thing for driver's safety on the road is equipment of crash cushion as a vehicle protection safety facility. But development of crash cushion is defective because there's no rational and reality way of design. And also without an alternative plan, it rely on crash test hereby it suffers a great economic loss and wastes time. This study that uses data of cash test proves the suitability of single degree of freedom which considers the safety of passengers about three-dimensional complicated Crash Analysis. As the study analyzes the conduct of crash cushion, it want to develop the effective method of design on Single Degree of Freedom Crash Cushion. And it presents the way of crash cushion design through making a crash analysis model with single degree of freedom. To verify the validness of the crash cushion plan, with single degree of freedom plan, we make the level CC2 crash cushion and execute the crash test. A performance test brings satisfied result and a plan of single degree of freedom crash cushion is proven as an one of the way to be a good system which can design crash cushion.

• Journal of the Korean Society of School Health
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• v.4 no.1
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• pp.88-99
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• 1991

The purpose of this study was attempted to analyze the relationship between drug abuse and the other problem behavior Patterns among high school students in Cheju. In order to achieve these set-goals, questionaires were finally supplied to the total 379 case of 9 high school from October to December, 1990. The collected data were processed using the SPSS-X computer program and statistically analyzed by the Chi-square method and. percentage. Results of the study were as follows: Among the 370 adolescents, 32.4% of students experienced cigarette smoking in their life, adolescents who experienced alcohol drinking were 46.8%, 0.5% of the students ever used marihuana; cocaine 0.3%, stimulant 3.2%, hallucinogen and inhalants 0.5%, tranquilizer 1.4%, analgesics 31:6%, antitussives 6.5%, antihistamines 1.9%. And all students never experienced the amphetamines and narcotics. The rates of drug use except stimulant and antitussive were higher in the male than in the female students. For the analysis of personal identifying datum, the rates of experienced smokers increased among groups of buddhist and the rates of experienced alconoi drinking increased among groups of no religion. Drug abuser increased among the group lower socio-economic status student, the adolescents whose parents have traditional education point of view. And it was also higher in those who were living only one than in those who were living together. Most students tended to use drugs after 17 or 18 years old. Drug users were more inclined to commit other problem behaviors when compared non-drug users. In the conclusion of the above results, it will be necessary to investigate the drug problem of adolescent. Drug abuse of students must be seen in an environmental context including family, school, peer group and society and not solely as the characteristics of an individual adolescent. And their parents and teachers must be on the alert for the behavior changes of their children such as changes of school performance, neglecting homework, tardiness or truancy from school, runaway from home, and mingled with bad companions, etc. We must recognize that drug abuse is frequently symptomatic of problems in the adolescent's environment.

• Safety and Health at Work
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• v.7 no.1
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• pp.6-11
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• 2016

Background: A permit to work (PTW) is a formal written system to control certain types of work which are identified as potentially hazardous. However, human error in PTW processes can lead to an accident. Methods: This cross-sectional, descriptive study was conducted to estimate the probability of human errors in PTWprocesses in a chemical plant in Iran. In the first stage, through interviewing the personnel and studying the procedure in the plant, the PTW process was analyzed using the hierarchical task analysis technique. In doing so, PTWwas considered as a goal and detailed tasks to achieve the goal were analyzed. In the next step, the standardized plant analysis risk-human (SPAR-H) reliability analysis method was applied for estimation of human error probability. Results: The mean probability of human error in the PTW system was estimated to be 0.11. The highest probability of human error in the PTW process was related to flammable gas testing (50.7%). Conclusion: The SPAR-H method applied in this study could analyze and quantify the potential human errors and extract the required measures for reducing the error probabilities in PTW system. Some suggestions to reduce the likelihood of errors, especially in the field of modifying the performance shaping factors and dependencies among tasks are provided.

• International Journal of Quality Innovation
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• v.7 no.1
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• pp.60-89
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• 2006

In the Knowledge-based Economic Era, all of the enterprises are facing global competitive pressure. The activities of knowledge accessing, codifying, and application will obviously become the main inner function on enterprise operation. Knowledge will be the primary competitive advantage; therefore, he who wants to hold the competitive advantage should do the knowledge management (KM) very well. In this study, we construct the research dimensions and variances by the successful factors of KM, which had been practiced very well by big enterprises inside and outside our country, and which was recommended by the related scholars. In order to approach the differences between big enterprises and small and medium-sized enterprises (SMEs) towards implementing KM, this study takes the way of questionnaire investigation to do empirical analysis and to construct the model of KM by path analysis. The study found out when implementing KM, SMEs should highlight 'leadership,' 'library-architecture,' and 'corporate culture' these three aspects, while 'information technology' and 'performance evaluation' these two aspects show no remarkable influence. It shows that he who wants to construct KM might not too overweight on information technology to build the KM system. Therefore, we suggest when implementing KM, enterprises should reinforce the corporate culture by sharing, organized KM process, learning environment for all employees, and highly authorization by top managers in order to reach the expectant success of KM. The result of this study offers practical thinking directions to reach the expectant success for the policy makers in SMEs, who are accessing to or evaluating to implement KM.