• Transactions of the Korean Society of Mechanical Engineers A
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• 제39권10호
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• pp.1039-1044
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• 2015

During the development of vehicles, durability tests are time consuming and costly. Recently, automobile companies have attempted to develop their own durability evaluation procedures by modifying and complementing . In this paper, we propose an integrated computer-aided engineering (CAE) method to evaluate the durability of a torsion beam axle (TBA). We compare this method with the standardized durability evaluation method used by an actual automobile company in order to determine the feasibility of this method. We compare the results with the test result data to enable us to estimate the reliability of the analysis results. In this study, we analyze the processes and results of the quasi-static fatigue analysis, and found improved methods and problems. Furthermore, we perform a thorough test using the requirements of the actual company. Based on the results, the structural analysis process in the quasi-static fatigue analysis method was superseded by the multi-body dynamics analysis process. Generally, this method is referred to as the resonance-fatigue analysis method.

• Journal of Korean Society of Industrial and Systems Engineering
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• 제39권1호
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• pp.37-46
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• 2016

Quality has been a key issue to manufacturers. Many distinguished scholars have defined quality with profound insight. Korean firms struggle to make better products to fulfil requirements and satisfy customers. Korean industries have implemented quality management from Japan in early 70s. Statistical quality control, QCC (Quality Control Circle), and total quality management have also been introduced in succession. Chief executive officers, managers, and field employees have been aware of the importance of quality since then. This quality movement force workers to improve quality. They have to maintain the quality of products and compete with foreign products. Korean industries were able to compete with foreign industries in price. However, Korean firms now have to compete in quality as well as price. ISO (International Organization for Standardization) was established and industries around world have started to implement standardized systems depending on their need. ISO 9000 has continuously been revised and firms around world started to register a ISO 9000 certificate. Today's quality competitiveness gets more deeply involved. KSA (Korean Standard Association) have launched QCAS (Quality Competitiveness Assessment System) since 1997. Up until now recent status of QCAS have been reported but the characteristics of QCAS results have not been analyzed. In this article we examine the QCAS results of 41 firms in 2014. QCAS consisted of 13 subsections : strategy and management system, organization culture and development of human resource, information management, quality system, customer satisfaction, management achievement, TPM, logistics, product development and technology, PL, QCC, SQC/SPC, and reliability. We performed one way ANOVA to discover the difference among the levels of firm size, business type, and quality hall of fame using the total scores of 13 subsections resulted from QCAS. We also analyzed the scores of 13 individual subsections of QCAS to see if there is any differences based on firm size and business type. We interpret the results and implication of analysis and finally draw a conclusion.

• Research in Community and Public Health Nursing
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• 제28권1호
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• pp.23-33
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• 2017

Purpose: The purpose of this research is to enhance organizational competitiveness of health centers as well as private medical institutions serving as public health and medical institutions. It tries to help them to cope with the requirements from health consumers, to enhance public health nurses' job performance, Methods: After verifying the reliability of the tool, confirmatory factor analysis was used to detect a model, in which valid path coefficients exist among variables. The detected model was then selected as the subject and its validity was verified. Finally, a structural equation model was applied to verify whether the estimate was suitable for the purpose of this research. Results: As for the nursing organizational culture, the public health nurses considered relation-oriented culture the most desirable. As for the self-leadership, they considered self-compensation the most desirable. It was found that mediating effects of self-leadership was partially significant. Conclusion: To enhance job performance, it is necessary to make a transition from the organizational culture to the relation-oriented culture and it is also necessary to develop a program capable of reinforcing self-leadership. In addition, it is necessary to conduct a research to verify whether such a developed self-leadership program is influential on job performance enhancement.

• Journal of the Korean Data and Information Science Society
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• 제24권3호
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• pp.557-569
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• 2013

Risk management activity for successful defense R&D project should be done anticipatorily and consistently over the entire project period and there should be a priority for management depending on importance of the risk factors. In this study, we verified the reliability and validity through factor analysis for the risk factors selected by the Delphi technique. We also obtained the relative importance of risk factors with analytic hierarchy process (AHP) and decided to prioritize for comparison of domestic and overseas research. According to the study, we found that it is important to settle the requirements and to classify the scope of R&D. It is also considered significant to have reasonable schedule for completion and secure the necessary resources in the early stage of project. Unlike previous studies, it appeared the technical factors are critical elements as well for defense R&D project.

• Fashion & Textile Research Journal
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• 제18권5호
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• pp.625-636
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• 2016

The purposes of this study were to investigate the effects of social appearance anxiety, negative body image, appearance importance on appearance management behavior and cosmetic surgery intention. For data collection, a questionnaire was administrated to 428 female college students in Gwangju City, Korea. The results were summarized as follows. To analysis the data, the SPSS 20.0 was used, and frequence analysis, descriptive statistical analysis, reliability analysis, regression analysis, F-test were conducted. The results were summarized as follows. First, social appearance anxiety turned out to have significant positive effect on appearance management behavior and cosmetic surgery intention. Second, negative body image had positive effect on appearance management behavior and cosmetic surgery intention. Third, appearance importance turned out to have significant effect on appearance management behavior and cosmetic surgery intention. The results of this study above suggest that it would be necessary to seek for measures to reduce individual's appearance anxiety, negative body image, and appearance importance. Especially, People should get the realization of the beautiful on the inside that includes personality is more important than having external beauty. And, it is considered that the requirements of the social effort and education through a school and a media as well as a family for reducing the individual's appearance anxiety, negative body image, and the serious consideration of the appearance as rejecting the discrimination based on appearance.

• Composites Research
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• 제15권1호
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• pp.53-60
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• 2002

Composite ablative tubes required capabilities of ablative and structural characteristics were fabricated through filament winding technique and several experiments were conducted to evaluate the structural performance of composite ablative tubes. For this purpose, manufacturing procedures were briefly described and then resin digestion method was applied to measure the fiber volume fraction and the void content of composite ablative tubes. The configuration of tensile specimen fur composite ablative tubes with not losing the continuity of reinforced fibers was suggested by evaluating mechanical properties of several types of the specimen with different widths. Also, suitable processing variables for composite ablative tubes were determined by evaluating mechanical properties of several types of the specimen with different processing variables. In addition, acoustic emission signals were obtained during the proof test and could be applicable to study the crack initiation and the damage mode of composite ablative tubes. Finally, the structural reliability of composite ablative tubes could be verified to satisfy design requirements through the proof and burst tests.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제39권6호
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• pp.561-566
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• 2015

In this paper, the operating stiffness of a parallel robot used to handle heavy packages is optimized. Because the studied model, called a "pick and place robot," is applied for packaging logistics, it is important for the robot to be lightweight so that it may respond rapidly and have high stiffness to allow sufficient operating precision. However, these two requirements of low weight and high stiffness are mutually exclusive. Thus, the dynamic characteristics of the robot are analyzed through multibody dynamics analysis, and topology optimization is conducted to achieve this exclusive performance. Lastly, the reliability of the topology optimization is verified by applying the optimized design to the parallel robot.

• KCID journal
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• 제17권2호
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• pp.57-70
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• 2010

This study was performed to analyze the affect of water supply capacity followed by allocating flood control volume in heightening reservoir, of which Baekgog reservoir was selected as a case study in here. Baekgog reservoir is located in Jincheon county, Chungbuk province, of which full water level will be heightened from EL. 100. 1m to EL. 102.1m, and total storage from 21.75M $m^3$ to 26.67M $m^3$. Flood inflow with 200year frequency was estimated to 997 $m^3$/s in peak flow and 22.54M $m^3$ in total volume. Reservoir flood routing was conducted to determine flood limited water levels, which was determined to have scenarios such as EL 97-98-99m in periods of 6.21.-7.20., 7.21.-8.20., and 8.21.-9.20., respectively, EL 97-97-97m, EL 98-98-98m in present reservoir, and EL 99-100-101m, EL 99-99-99m, and EL 100-100-100m in heightened reservoir. Reservoir inflow was simulated by DAWAST model. Annual paddy irrigation requirement was estimated to 33.19M $m^3$ to 2,975ha. Instream flow was allocated to 0.14mm/d from October to April. Operation rule curve was drawn using inflow, irrigation and instream flow requirements data. In case of withdrawal limit reservoir operation using operation rule curve, reduction rates of annual irrigation supply before and after flood control by reservoir were 2.0~4.3% in present size and 1.5~3.6% in heightened size. Reliability on water supply was decreased from 77.3% to 63.6~68.2% in present size and from 81.6% to 72.7~79.5% in heightened size. And reduction rates of water storage at the end of year before and after flood control by reservoir were 7.3~16.5% in present size and 7.7~16.9% in heightened size. But water supplies were done without any water deficiency through withdrawal limit reservoir operation in spite of low flood regulating water level.

• Journal of Advanced Navigation Technology
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• 제23권6호
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• pp.589-596
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• 2019

With the proliferation of intelligent transportation system (ITS) with dedicated short-range communication (DSRC) deployment, there are various applications requiring different throughput and reliability performance. To meet the enhanced throughput requirements in newly generated applications, IEEE 802.11bd is proposed to standardize for support of enhanced throughput and latency, preserving the fairness with previously deployed WLAN V2X devices. One of the main features of IEEE 802.11 bd is 20 MHz transmission to support the high data rate. In this paper, the primary channel selection method is proposed to guarantee the fairness with frame transmissions with 10 MHz bandwith including communications in WLAN V2X devices deployed with IEEE 802.11p. Simulation shows that the proposed channel access method for 20 MHz transmission with primary selection preserves the fairness without the change of channel access method in wide-band transmission.

• Journal of KIISE:Software and Applications
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• 제32권10호
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• pp.963-973
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• 2005

Increasing attention is being recently devoted to various problems inherent in the topological design of networks systems. The topological structure of these networks can be based on service centers, terminals (users), and connection cable. Lately, these network systems are well designed with tiber optic cable, because the requirements from users become increased. But considering the high cost of the fiber optic cable, it is more desirable that the network architecture is composed of a spanning tree. In this paper, we present a GA (Genetic Algorithm) for solving bicriteria network topology design problems of wide-band communication networks connected with fiber optic cable, considering the connection cost, average message delay, and the network reliability We also employ the $Pr\ddot{u}fer$ number (PN) and cluster string in order to represent chromosomes. Finally, we get some experiments in order to certify that the proposed GA is the more effective and efficient method in terms of the computation time as well as the Pareto optimality.