• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1255-1263
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• 2008

A Safety Case is an railway organization's formal arrangement, through the provision of policies, resources and processes, to ensure the safety of its work activity within safety management system. An effective system helps the organization to identify and manage risks effectively. It allows an organization to demonstrate its capability in achieving its safety objectives and in meeting regulatory requirements. The purpose of this research is to give how to the risk assessments are described within Railway Safety Cases can be prepared and maintained to meet the criteria specified by the upcoming railway regulations. Through this research, we propose the elements of safety management system that include arrangements for the ongoing identification of hazards, assessment of risks and the implementation of necessary control measures.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.2
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• pp.136-141
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• 2002

The electrical characteristics of solid state devices such as BJT(Bipolar Junction Transistor) and MOSFET, etc, are altered by impinging nuclear radiation and temperature in the space environment. This phenomenon is well known and has been studied extensively since the early 1960's when satellites were first being designed and used in the United States. However, the studies and the developments of radiation hardening technologies for the electronic components at the industrial fields in our country has not been popular so far. The worst case design technology in the electrical circuit is required for the appropriate operation of solid state devices in the space environment. In this paper, the interface circuit used in KOMPSAT(Korea Multipurpose Satellite), which is now being operated since the one was launched in 1999, is optimally designed to accomodate the worst case design and radiation effect.

• Journal of Periodontal and Implant Science
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• v.32 no.2
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• pp.415-428
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• 2002

Periodontal disease is a complex infectious disease caused by bacteria in the oral mucosa, which results in gingival inflammation, breakdown of periodontal tissues, bone resorption, and finally tooth loss. Mechanical plaque control methods-scaling and root planing are effective methods to stop the progression of such periodontal disease. It was reported that subantimicrobial dose of doxycycline(SDD) regimen could improve clinical conditions of periodontal tissues without causing the overgrowth of opportunistic organisms that was a typical antibiotic side effect. Therefore pharmacological therapy, used in conjunction with mechanical therapy could be considered a useful treatment modality in the treatment of chronic periodontal disease. In this study, 30 patients diagnosed as moderate to advanced chronic periodontitis were divided into 2 groups. In this double-blind, placebo-controlled study, the patients were administered 20mg doxycycline capsule or placebo capsule b.i.d. for 4months, after scaling and root planing. Clinical parameters-bleeding on probing, pocket depth and clinical attachment level were compared and evaluated between these groups at periods of first visit, 1 month, 2 months, 3 months, 4 months. The results were as follows ; 1. In case of moderate periodontitis, pocket depth showed significant reduction after treatment in both the control & experiment groups, when compared with the baseline values(p<0.01), but in case of advanced periodontitis, only the experiment group showed significant reduction after treatment when compared with the baseline values(p<0.05). Statistically significant reduction in pocket depth was observed in the experiment group compared to the control group(p<0.05). 2. In case of moderate periodontitis, clinical attachment level showed significant reduction after treatment in both the control & experiment groups, when compared with the baseline values(p<0.01), but in case of advanced periodontitis, only the experiment group showed significant reduction after treatment when compared with the baseline values(p<0.05). Statistically significant reduction in clinical attachment level was observed in the experiment group compared to the control group(p<0.05). 3. Bleeding on probing improved after treatment in both the groups. In case of moderate periodontitis, the experiment group showed statistically significant reduction of bleeding on probing when compared with the control group at 1 and 4 months after treatment(p<0.05). In case of advanced periodontitis, treatment resulted in statistically significant reduction of bleeding on probing in both the groups(p<0.05). These results indicate that the use of subantimicrobial dose of doxycycline is a useful supplement to mechanical treatment for periodontal patients in ameliorating the clinical parameters such as periodontal pocket, attachment level, and bleeding on probing.

• Korean Journal of Oriental Medicine
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• v.13 no.2 s.20
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• pp.65-69
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• 2007

Background and Purpose : The purpose of this case-control study was to show the relationship between risk factors(past medical history, BMI, WHR, smoking, drinking), warning signs(dyscinesia, sightless, dysarthria, sensory disorder, numbness, blephalospasm, facial spasm, tension) and the incidence of stroke in korean adults. Methods : 455 stroke patients were enrolled as the case group and 180 non-stroke patients as control group from Oct. 2005 to Feb. 2006. Patients were hospitalized within 2 weeks after the onset of stroke. Obesity were defined as $BMI{\geq}25kg/m2$, $WHR{\geq}0.9$ in male and $WHR{\geq}0.8$ in female. Risk factors and warning signs were obtained from personal interview. The analysis of the data was done by chi-square test. Fisher's exact test and test-sample t-test. Results : The percentage of current smokers(or current drinkers) of case group is higher significantly than that of control group. The past medical history of risk factors were found to be transient ischemic attack(p=0.0698), facial palsy(p=0.4061), hypertension(p<0.0001), hyperlipidemia(p=0.1484), DM(p<0.0001), ischemic heart disease(p=0.0093), migraine(p=0.0014) and hypochondria(p=0.2370). $WHR{\geq}0.9$ in male had a 6.696 (3.711-12.082) odds ratio, $WHR{\geq}0.8$ in female had a 1.567 (0.659-3.726) odds ratio. $BMI{\geq}25kg/m2$ had a 2.017(1.263-3.222). The dyscinesia and sensory disorder of warning signs were found to be statistical difference between case and control group. Conclusions : According to the above results, it was found that smoking, drinking, BMI, WHR, hypertension, DM, ischemic heart disease, migraine affected to the incidence of stroke.

• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.43-50
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• 2009

In order to reduce the download around Smart UAV(SUAV) at hovering and transition mode, flow control using synthetic jet has been performed. Many of the complex tilt rotor flow features are captured including wing leading and trailing edge separation, and the large region of separated flow beneath the wing. First, in order to control the trailing edge separation, synthetic jet is located at 30, 95% of flap chord length. The flow control using synthetic jet on flap shows that stall characteristics depending on several mode can be improved through separation vortices resizing. Also, a flap jet and a 0.01c jet which control the separation efficiently are applied at the same time at each test case because controlling the leading edge separation is essential for download reduction. As a result, time averaged download is reduced about 18% comparing with no control case at hovering mode and 48% at transition mode. These research results show that if flow control using leading edge jet and trailing edge jet is used effectively to the SUAV in overall flight mode, flight performance and stability can be improved.

• International Journal of Automotive Technology
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• v.5 no.4
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• pp.269-276
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• 2004

There has been considerable activity in recent years in developing timing analysis algorithms for distributed real-time control systems. However, it is difficult for control engineers to analyze the timing behavior of distributed real-time control systems because the algorithms was developed in a software engineer's position and the calculation of the algorithm is very complex. Therefore, there is a need to develop a timing analysis tool, which can handle the calculation complexity of the timing analysis algorithms in order to help control engineers easily analyze or develop the distributed real-time control systems. In this paper, an interactive timing analysis tool, called RAT (Response-time Analysis Tool), is introduced. RAT can perform the schedulability analysis for development of distributed real-time control systems. The schedulability analysis can verify whether all real-time tasks and messages in a system will be completed by their deadlines in the system design phase. Furthermore, from the viewpoint of end-to-end scheduling, RAT can perform the schedulability analysis for series of tasks and messages in a precedence relationship.

• Fire Science and Engineering
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• v.31 no.2
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• pp.24-28
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• 2017

This study compared the performance of a smoke control system in the case of a fire with that in the case of non-fire. Single-pressurization in the vestibule, single-pressurization in the stairwell, simultaneous smoke control of the stairwell and vestibule, which was the pressurization of smoke control, were assessed. The result showed that simultaneous smoke control of the stairwell and vestibule can maintain the differential pressure and is least influenced for the evacuation of evacuees. In addition, for the status of smoke control in Korea and the proper pressurization method, these results highlight the necessity of improving the current pressurization method through the survey.

• Korean Journal of Computational Design and Engineering
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• v.18 no.3
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• pp.177-188
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• 2013

The construction industry consists of various and massive architectural information as an architectural process includes a variety of design stages with cooperation of many disciplines. Particularly, architectural information is generated and managed through the life cycle of a building, from conceptual design stage to the construction and maintenance. A Building Information Model (BIM) serves as a shared knowledge resource for information about a facility forming a reliable basis for decisions during its life-cycle from inception onward. BIM technology accomplished quantitative development being utilized in various disciplines. However, it is necessary to develop environment and requirement for qualitative improvement of BIM based project. Particularly, requirement is very important for architectural design evaluations. The purpose of this study is to develop and apply of quality control check-list for improving the quality of architectural design in BIM environments. To achieve this purpose, the authors have investigated case study for open BIM data quality control (software, guideline and application case) and classified quality control targets according to physical/logical quality control and data quality. In addition, the authors have defined open BIM based quality control process and developed quality control check-list. Finally, the authors have developed automatic quality check system using requirements for efficient quality control based on open BIM.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.620-628
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• 2005

Spatial control of sound is essential to deliver better sound to the listener's position in space. As it can be experienced in many listening environments, the quality of sound can not be manifested over every position in a hall. This motivates us to control sound in a region we select. The primary focus of the developed method has to do with the brightness and contrast of acoustic image in space. In particular, the acoustic brightness control seeks a way to increase loudness of sound over a chosen area, and the contrast control aims to enhance loudness difference between two neighboring regions. This enables us to make two different kinds of zone - the zone of quiet and the zone of loud sound - at the same time. The other perspective of this study is on the direction of sound. It is shown that we can control the direction of perceived sound source by focusing acoustic energy in wavenumber domain. To begin with, the proposed approaches are formulated for pure-tone case. Then the control methods are extended to a more general case, where the excitation signal has broadband spectrum. In order to control the broadband signal in time domain, an inverse filter design problem is defined and solved in frequency domain. Numerical and experimental results obtained in various conditions certainly validate that the acoustic brightness, acoustic contrast, direction of wave front can be manipulated for some finite region in space and time.

• International conference on construction engineering and project management
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• 2013.01a
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• pp.426-432
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• 2013

The construction industry consists of various and massive architectural information as an architectural process includes a variety of design stages with cooperation of many disciplines. Particularly, architectural information is generated and managed through the life cycle of a building, from conceptual design stage to the construction and maintenance. A Building Information Model (BIM) serves as a shared knowledge resource for information about a facility forming a reliable basis for decisions during its life-cycle from inception onward. BIM technology accomplished quantitative development being utilized in various disciplines. However, it is necessary to develop environment and requirement for qualitative improvement of BIM based project. Particularly, requirement is very important for architectural design evaluations. The purpose of this study is to develop and apply of quality control requirement for improving the quality of architectural design in open BIM environments. To achieve this purpose, the authors have investigated case study for open BIM data quality control (software, guideline and application case) and classified quality control targets according to physical/logical quality and data quality. In addition, the authors have defined open BIM based quality control process and developed quality control requirements. Finally, the authors have developed rule based quality check system using requirements for efficient quality control based on open BIM.