• Korean Journal of Optics and Photonics
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• v.26 no.3
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• pp.155-161
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• 2015

We report the design and performance analysis of an off-axis three-mirror telescope as the fore optics for a new hyperspectral sensor aboard a small unmanned aerial vehicle (UAV), for low-altitude coastal remote sensing. The sensor needs to have at least 4 cm of spatial resolution at an operating altitude of 500 m, $4^{\circ}$ field of view (FOV), and a signal to noise ratio (SNR) of 100 at 660 nm. For these performance requirements, the sensor's optical design has an entrance pupil diameter of 70 mm and an F-ratio of 5.0. The fore optics is a three-mirror system, including aspheric primary and secondary mirrors. The optical performance is expected to reach $1/15{\lambda}$ in RMS wavefront error and 0.75 in MTF value at 660 nm. Considering the manufacturing and assembling phase, we determined the alignment compensation due to the tertiary mirror from the sensitivity, and derived the tilt-tolerance range to be 0.17 mrad. The off-axis three-mirror telescope, which has better performance than the fore optics of other hyperspectral sensors and is fitted for a small UAV, will contribute to ocean remote-sensing research.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.1
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• pp.137-142
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• 2014

Industrial control system (ICS) is a computer based system which are typically used in nation-wide critical infra-structure facilities such as electrical, gas, water, wastewater, oil and transportation. In addition, ICS is essentially used in industrial application domain to effectively monitor and control the remotely scattered systems. The highly developed information technology (IT) and related network techniques are continually adapted into domains of industrial control system. However, industrial control system is confronted significant side-effects, which ICS is exposed to prevalent cyber threats typically found in IT environments. Therefore, cyber security vulnerabilities and possibilities of cyber incidents are dramatically increased in industrial control system. The vulnerabilities that may be found in typical ICS are grouped into Policy and Procedure, Platform, and Network categories to assist in determining optimal mitigation strategies. The order of these vulnerabilities does not necessarily reflect any priority in terms of likelihood of occurrence or severity of impact. Firstly, corporate security policy can reduce vulnerabilities by mandating conduct such as password usage and maintenance or requirements for connecting modems to ICS. Secondly, platfom vulnerabilities can be mitigated through various security controls, such as OS and application patching, physical access control, and security software. Thirdly, network vulnerabilities can be eliminated or mitigated through various security controls, such as defense-in-depth network design, encrypting network communication, restricting network traffic flows, and providing physical access control for network components.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2541-2549
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• 2013

The Construction industry has been dealing with much trouble due to global economic recession and domestic political trends emphasizing on welfare than development. Consequently, domestic construction market has been dramatically shrunk during the last a few years, and international market has become the only potential solution for the industry. However, there has been lack of efforts in developing a quantified measure of global competencies for Korean engineering and construction organizations. This study attempted to develop quantified indices for Korean engineering and construction contractors with which the level of global construction competencies can be objectively monitored. In doing so, a survey questionnaire was developed to identify relative importances of core competency elements which were derived from extensive literature reviews and experts interviews. AHP (Analytic Hierarchy Process) was employed as a main analysis method in developing quantification measures. The analysis results reveal little differences in competency requirements between engineering and construction firms and it implies that the global market becomes more integrated and requires a total solution for a construction project. The developed core competency measures can be used to quantify the level of preparedness of Korean engineering and construction firms at the time of evaluation and also be used as a basis for performance benchmarking indicators if they are compared with business showings.

• Spatial Information Research
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• v.11 no.1
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• pp.41-60
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• 2003

It is noted that the paper mapping system for University Building Facility has many limitations in terms of data maintenance, real-time GIS data acquisition, and economic efficiency. The aim of this research was to evaluate an operational potential of an on site real-time mobile GIS technique to resolve the problem faced in the university. The idea is based upon the recent trends in the field of 'Telecommunication and Information Technology' that uses a PDA (personal Digital Assistants), wireless network computing, mobile computing, etc. A real time mobile GIS approach has been adopted, in which a PDA is linked to a wireless internet and field workers record data on the computer at the site and analyse data on site. While there should be a considerable number and variety of factors associated with real-time mobile GIS quality, this research focuses on three criteria that are identified as fundamental to customer requirements; (1) data quarry (2) spatial analysis (3) real-time GIS database building. 'Art--empirical study for a case study facility has been conducted to confirm the validity for the system. The system has been checked experimentally, enabled the field users to quarry the data required simply and execute spatial analysis (buffer, overlay etc.,) accommodating versatile alternatives on the site. Detailed visual maps can be generated over large areas quickly and easily. The PDA interface, in particular, were ideally suited for field users to interactively displaying positional information with attribute data. This system has shown to be quite convenient to maintaining a highly reliable database since it could playa crucial role in documenting at real-time basis temporal and spatial changes occurred in the facilities. It is anticipated that this research output will greatly serve to introduce the reliable and cost-effective facility mapping system in the university by overcoming serious constraints suffered from the past non-real time mobile GIS approach.

• Journal of Acupuncture Research
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• v.27 no.4
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• pp.147-178
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• 2010

Objectives : This study was to propose the improved instruction for authors and research ethic regulations by the comparative analysis of those of the domestic journals, for the purpose of enhancing the citation rate of Journal of Korean Acupuncture and Moxibustion Society. Methods : Narrative review method was used for comparatively analyzing instruction for authors of 34 domestic journals, especially focused on how to write a reference. Thereafter, in order to elucidate the drawbacks of current instruction for authors and research ethic regulations of the acupuncture and moxibustion society, the well prepared instructions and research ethic regulations was selected from them, which were compared with the present instructions for authors and research ethic regulations of the acupuncture and moxibustion society. Results : As a result of the comparative analysis of instruction for authors in the 34 domestic journals, style for references was based largely on that of National Library of Medicine and vancouver at the same time. The number of reference was limited according to types of writings. for example, the original article and case report was frequently limited to 40 and 20 references respectively. Authors were mostly listed up to six. If there are more, the first three or six authors were listed with 'et al'. it was generally recommended that using abstracts as references should be avoided and References to papers accepted but not yet published should be designated as 'in press' or 'forthcoming', and that the names of journals should be set in italics and abbreviated according to the List of Journals Indexed for Medline (formerly Index Medicus) published by the National Library of Medicine or koreanmed or WHO-IST, etc. In addition, citation of electrical literature, English writing of reference and obligational citation of more than two articles in the journals were encouraged. In consequence of comparison between well prepared instructions and research ethic regulations of the selected journals and those of current instructions for authors and research ethic regulations of the acupuncture and moxibustion society, the followings were needed to be added or revised. 1. Requirements for case reports were not mentioned. 2. Reporting Guidelines for Specific Study Designs were not included. 3. Previous Orthography of herbal prescription should be revised. 4. Orthography of authors and guidelines for writing article constituents such as title, abstract, introduction, method, statistics, results, discussions were not presented. 5. How to write a reference was so simplified. 6. Definition of Research Ethical Misconduct was omitted and establishment, management and members of committee for research ehtics were not mentioned, 7. Information, reception and investigative procedures of Research Ethical Misconduct was not specified. Conclusions : For the development of Journal of Korean Acupuncture and Moxibustion Society, apporopriate revision of the instruction for author and research ethic regulations should be made based upon the above findings. English writing of reference were believed to be one of the alternatives enhancing citation rate.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.12
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• pp.1087-1094
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• 2016

The responsibility of the vehicle holding device (VHD) is to hold the launch vehicle while it is stayed on launch pad and release the holding mechanism to allow a lift-off of launch vehicle at a moment of lift-off. During a release of the holding mechanism, in order to prevent the Ka doing a doing a doing mode which is vertical oscillation of entire liquid propellant and very severe for vehicle structure, gradual release of holding force is required. Also, a release operation of all 4 VHD should be synchronized very precisely. In this study, to comply the "gradual release and synchronized operation requirement", concept of VHD hydraulic system using an accumulator, pyro valve and orifice to control speed of hydraulic cylinder is proposed instead of using complicated hydraulic components. Then through multi-body dynamic analysis and computational hydraulic analysis, a size of orifice to meet a target speed of hydraulic cylinder is calculated. Through this study, simple and reliable VHD hydraulic system complying requirements is designed.

• Journal of Energy Engineering
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• v.23 no.3
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• pp.186-190
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• 2014

Nuclear Power Plants require the control ability of chemical condition (pH) because pH control during transient accident such as LOCA makes an able the fission product removal capability to be maintained, stress corrosion cracking of stainless steel equipment to be prevented and the production of hydrogen by aluminum and zinc to be minimized. An NPP is designed to control the pH of containment spray and sump coolant using the spray additives 30% NaOH in the event of loss of coolant accident. In this paper, the pH of sump coolant of an NPP during LOCA was analyzed and the fission products removal constant and decontamination factor were calculated according to Standard Review Plan 6.5.2 related to spray chemical conditions of pH. The calculated pH value of recirculation mode using the computer code corresponds to 8.09~9.67, which meets the chemical environment regulation requirements. The fission product removal capability caused by containment spray system is performed to provide input to radiation analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.12
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• pp.8700-8706
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• 2015

The first driving device of the power bogies for the Korean high-speed railway vehicle consists of the traction motor (TM) and the motor reduction gears unit (MRU). Although TM and MRU are the mechanically integrated structures, their time between overhauls (TBO) have two separate intervals due to different technical requirements(i.e. TBO of MRU: $1.8{\times}10^6km$, TBO of TM: $2.5{\times}10^6km$). Therefore, to reduce the unnecessary number of preventive maintenances, it is important to evaluate the optimal TBO with a viewpoint of reliability-center maintenance towards cost-effective solution. In this study, derived from the field data in maintenance, fault tree analysis and failure rate of the subsystem considering criticality of the components are evaluated respectively. To minimize the conventional total maintenance cost, the same optimal TBO of the components is derived from genetic algorithm considering target reliability and improvement factor. In this algorithm, a chromosome which comprised of each individual is the minimum preventive maintenance interval. The fitness function of the individual in generation is acquired through the formulation using an inverse number of the total maintenance cost. Whereas the lowest common multiple method produces only a four percent reduction compared to what the existing method did, the optimal TBO of them using genetic algorithm is $2.25{\times}10^6$km, which is reduced to about 14% comparing the conventional method.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.5
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• pp.442-448
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• 1999

We introduce the systematization design method using similarity theory which is profitable in the c compatability and standardization of the developed products and the reduction of construction time and price to d develop and design a machine equipment. Systematization design method is to select the standard model for d designing and developing from the large machinery to the super precision one and then to induce the c characteristic of machines step by step in advance in case of miniaturizing and making largelongleftarrowscale. With this m method, we extract the peculiar characteristics through the close analysis on the physical and ttx:hnical part a and predict the characteristic experiment for the magnitude we desire by an머ogical mathematical analysis. At l last, we will get the design sample the users demand with the verification of the data on optimum design p previously. In this paper, we could predict the characteristic of the product the users rC'Quire in advance with the d design method applying similarity theor${\gamma}$ and suggested the design method which could meet the various r requirements the users want. Also, it is shown that the standardization design by the similarity theory is a available as comparing the characteristic values expc'Cted through the experiment of the actual actuator with t the theoretical character data of similarity theoη after selecting the linear actuator as a model.

• International Commerce and Information Review
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• v.14 no.3
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• pp.281-306
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• 2012

Global competition has resulted in companies' expectations to heighten competitiveness and enhance customer service through ownership companies' reduced investment on logistics costs, in turn focusing on the development of core competence, in addition to logistics companies' increased tendencies to satisfy customers' needs and requirements through logistics outsourcing. However, a partial perspective of the logistics contract exists due to its flexible characteristic in order to act accordingly in times of sudden changes and uncertainty. Therefore, this study is designed to test through a survey the standard of desired format of logistics contract in comparison to the currently existing format based on the results of researcher's previous study on the specific clauses in the logistics contract and its effect on the logistics outcome. A hypothesis has been designed to test the differences of perspective between two test groups, and a t-test &IPA (Importance-Performance Analysis) was performed. As a result, firstly, there was a significant difference of perspective between the ownership companies and logistics companies when dealing with the logistics contract; secondly, a significant difference of perspective was also expressed between the two groups on how to guide and re-direct the present standard of logistics contract. In addition, the two groups also showed a difference of expectations between the current and future service standard. Therefore, this study is designed to specify the difference of perspective and expectations between the ownership companies and the logistics companies in order to provide a gateway for the two groups in order to further develop and enhance the field of logistics.