• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1987년도 한국자동제어학술회의논문집; 한국과학기술대학, 충남; 16-17 Oct. 1987
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• pp.658-663
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• 1987

The new controller developed here, which is the facility with only one measurement, is a new concept for the level controller of the existing nuclear steam generator. A MACS (Microcomputer-based Adaptive Control System of a Steam Generator) is quite practical and efficient, and has also simple structure and higher flexibility in the installment for actual plant. A key ingredient of this system is adaptive regulator which can calculate adaptive, optimal valve position in response to changes in the dynamics of the process and the disturbances. In spite of many difficulties in the steam generator water level control at low power, it can be concluded from the experimental and simulation results, that the MACS can provide optimal, robust steam generator level control from zero to full power. The amount of the control input effort can be reduced by adjusting the weighting factor. However, the steady state water level errors are generated. To avoid the steady errors, the different adaptive algorithm should be investigated in the future. The 3 second sampling time is acceptable for this system. However, action should be taken to shorten the sampling time for better digital control.

• Journal of Korea Technology Innovation Society
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• 제6권4호
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• pp.551-568
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• 2003

The aircraft industry is a typical complex product system (CoPS) and one of the system integration industries. In this particular sector, industrial competitiveness is decided by technological capabilities in system level as well as subsystem level. Korea has been involved in the aircraft industry since early 1970s. Technological capability in the system level has been developed based on military aircraft production program. However, subsystem and component level capabilities have been remained less developed. In this paper, the capability building process as well as current problem; of the Korean aircraft industry have been examined. In conclusion, capability building up strategies in the Korean aircraft industry has been suggested.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국해양정보통신학회 2003년도 춘계종합학술대회
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• pp.749-752
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• 2003

The HLA is defined by three components: (1) Rules, (2) the HLA Interface Specification, and (3) the Object Model Template(OMT). The RTI(Run-Time Infrastructure) software implements the interface specification. It provides services in a manner that is comparable to the way a distributed operating system provides services to applications. A way to test whether is suitable for a standard, and all service was implemented is tested through two phases of processes to verify the RTI which proposed in DMSO. In this paper, we discuss Level One Test Procedures and a method. Confirms whether RTI was implemented in Interface Specification according to Level One Test Procedures appropriately through a test. Develops Test Suite for every each step to test whether a correct command and the expected results are occur.

• Journal of the Institute of Electronics Engineers of Korea SD
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• 제45권4호
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• pp.78-85
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• 2008

This paper presents a high-level design methodology applied on an SoC using SystemC. The topic will emphasize on high-level design approach for intensive architecture exploration and verifying cycle accurate SystemC models comparative to real Verilog RTL models. Unlike many high-level designs, we started the poject with working Verilog RTL models in hands, which we later compared our SystemC models to real Verilog RTL models. Moreover, we were able to use the on-chip test board performance simulation data to verify our SystemC-based platform. This paper illustrates that in high-level design, we could have the same accuracy as RTL models but achieve over one hundred times faster simulation speed than that of RTL's. The main topic of the paper will be on architecture exploration in search of performance degradation in source.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• 제25권4호
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• pp.482-492
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• 2015

Objectives: Exposure Assessment for workplace hazards where the exposure level is below occupational exposure limits(OELs) has been performed without considering either the degrees of risk or exposure levels and has failed to lead to intervention in many cases. The objective of this study was to suggest and test an application framework for risk assessment methodology under the current exposure assessment system in Korea. Materials: First, we investigated the exposure assessment systems in Korea and other countries. To adopt some risk assessment techniques, we also analyzed risk assessment systems and compared them to exposure assessment systems. A few suggestions were made. We held a public hearing during an industrial hygiene conference and took surveys using a questionnaire. Results: The first suggestion was to implement the risk assessment and exposure assessment through a "one-stop" system. In that case, one expected question would be who has been doing the jobs so far. In most cases, industrial hygiene consulting services or laboratories have been performing exposure assessment for business owners. Business owners are required to perform risk assessment. As two different groups of people will be required to implement two things in a one-stop system, they need to share information. As an information vehicle to share information, commonly filed survey checklists were suggested. The second suggestion was to categorize exposure level into four groups instead of the current binary divisions based on OELs. In the risk assessment system, exposure level is divided into four groups utilizing the cut-points of 10%, 50%, and 100% of OELs. The same schema can be adopted in the exposure assessment system and different levels of requirements can be assigned for each group. The third suggestion was regarding the regulation system. To provide the suggestions some thrust toward being implemented in the field, changes should be made in the legal system. Two different types of new exposure assessment result reporting forms were suggested. Some investigations such as an ergonomic survey are officially accepted as risk assessment under the current legal system. A few items were suggested to be included in the exposure assessment result reporting to be accepted as risk assessment. A pilot study in two small factories was performed and pointed out the strengths and weakness of our suggestions. Conclusions: Discussions and studies on the improvement of the exposure assessment system have been held for decades and no tangible changes have yet been made. We hope this result can help realize healthy lives for workers in Korea.

• Industrial Engineering and Management Systems
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• 제8권2호
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• pp.80-92
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• 2009

This paper addresses the inventory rationing issue embedded in the regional supply chain inventory replenishment problem (RSIRP). The concerned supply chain, which was fed by the national supply chain, consisted of a single warehouse distributing a single product to multiple stores (M-stores) with independent and normally distributed customer demand. It was assumed that the supply chain operated under the order-up-to level inventory replenishment system and had only one truck at the regional warehouse. The truck could make one replenishment trip to one store per period (a round trip per period). Based on current inventories and the vehicle constraint, the warehouse must make two decisions in each period: which store in the region to replenish and what was the replenishment quantity? The objective was to position inventories so as to minimize lost sales in the region. The warehouse inventory was replenished in every fixed-interval from a source outside the region, but the store inventory could be replenished daily. The truck destination (store) in each period was selected based on its maximum expected shortage. The replenishment quantity was then determined based on the predetermined order-up-to level system. In case of insufficient warehouse inventories to fulfill all projected store demands, an inventory rationing rule must be applied. In this paper, a new inventory rationing rule named Expected Cost Minimization (ECM) was proposed based on the practical purpose. The numerical results based on real data from a selective industry show that its performance was better and more robust than the current practice and other sharing rules in the existing literature.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제57권3호
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• pp.416-420
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• 2008

This paper proposes a new method to improve signal characteristics at branches frequently met in system-level routing. We also introduce the numerical formula which can estimate the time delay due to branches and the simple design guideline for system-level routing. Finally, we propose the routing method which can eliminate the signal reflection for the case of one driver and two receivers (multi-drop topology).

• Journal of Korean Society for Quality Management
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• 제41권3호
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• pp.395-404
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• 2013

Purpose: Technology readiness assessment(TRA) used as a standard readiness assessment tool in the acquisition program of weapon system has some limitations in the comprehensive understanding of the complex system. Therefore, this research is intended to suggest a holistic maturity assessment method for the acquisition of high quality weapon system. Methods: Technology readiness level(TRL), manufacturing readiness level(MRL), integration readiness level(IRL) and system readiness level(SRL) developed to assess system maturities in the various aspects are compared and analyzed to draw an improvement avenue for the current readiness assessment method. Results: TRL, MRL, IRL and SRL have large differences in their maturity targets during the acquisition life cycle: technological performance, manufacturing capability, interface between components and total system, respectively. They complement one another's shortcomings Conclusion: To achieve a successful acquisition of high quality weapon system, multi-dimensional readiness assessment is required. Therefore, comprehensive readiness assessment using TRL, MRL, IRL and SRL will contribute to the acquisition of high quality weapon system through the accurate maturity information of overall system.

• Journal of International Academy of Physical Therapy Research
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• 제5권2호
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• pp.723-729
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• 2014

The purpose of this study is to understand the relationship between female college students' stress level and premenstrual syndrome so that it can provide baseline data on how to cope with the syndrome. The study subjects are 250 female college students in Gyungbook area. This study chose 199 appropriate subjects and collected data. As per general menstrual phases, this study investigated the age when one had her first period, regularity and duration of period, and amount of bleeding. It used a measurement tool to measure stress level and premenstrual syndrome. Most of the subjects experienced their first period before the age of 13. The menstrual period was irregular with the duration of less than 7 days. 123 subjects had normal amount of bleeding. 121 subjects were experiencing high level of stress over 2.4. The correlation between the level of stress and premenstrual syndrome factors showed significant static correlation for each factor. Especially, the correlation between digestive system and response of autonomic nervous system was .996 and negative emotion and behavioral change was .635, and negative emotion and pain was .614 which were relatively high. The regression analysis of factors of premenstrual syndrome depending on the subjects' stress level indicated that response of autonomic nervous system had the biggest effect in the low stress group while behavioral change, negative emotion, pain, decreased concentration, water congestion, response of autonomic nervous system, and skin change had the biggest effect in the high stress group with statistical significance. Based on the result, it can be said that higher premenstrual stress is closely related to the premenstrual syndrome one experiences for some female college students.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• 제5권3호
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• pp.40-49
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• 1996

The problem related to the rotational vibration at steering wheel end of passenger cars during high speed driving is investigated. to analyze vibration of steering wheel, a steering system of passenger car is modelled in twelve degrees of freedom including backlash effect of rack and pinion gear system. The one degree of freedom system with backlash in investigated by the analytical method. Consequently the skeleton curve and the frequency response curves are computed. The steering system is analyzed by the numerical simulation using the 4th order Runge-Kutta method, the obtained results are compared with the experimental data. Also the effects of the change of rack gear tooth stiffness and backlash on the acceleration level of steering wheel are investigated. As a result, it can be found that the acceleration level of steering wheel becames lower as the rack gear tooth stiffness becames higher, and that acceleration level becames high as the magnitude of backlash between rack and pinion gear increase.