• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.1886-1900
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• 2018

This paper proposes a confronting feedback control structure and controllers for positive output elementary super lift Luo converters (POESLLCs) working in discontinuous conduction mode (DCM). The POESLLC offers the merits like high voltage transfer gain, good efficiency, and minimized coil current and capacitor voltage ripples. The POESLLC working in DCM holds the value of not having right half pole zero (RHPZ) in their control to output transfer function unlike continuous conduction mode (CCM). Also the DCM bestows superlative dynamic response, eliminates the reverse recovery troubles of diode and retains the stability. The proposed control structure involves two controllers respectively to control the voltage (outer) loop and the current (inner) loop to confront the time-varying ON/OFF characteristics of variable structured systems (VSSs) like POESLLC. This study involves two different combination of feedback controllers viz. the proportional integral controller (PIC) plus sliding mode controller (SMC) and the fuzzy logic controller (FLC) plus SMC. The state space averaging modeling of POESLLC in DCM is reviewed first, then design of PIC, FLC and SMC are detailed. The performance of developed controller combinations is studied at different working states of the POESLLC system by MATLAB-Simulink implementation. Further the experimental corroboration is done through implementation of the developed controllers in PIC 16F877A processor. The prototype uses IRF250 MOSFET, IR2110 driver and UF5408 diodes. The results reassured the proficiency of designed FLC plus SMC combination over its counterpart PIC plus SMC.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.8
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• pp.89-95
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• 2008

This paper describes the checking results and some problems of guard lamps installed in the field. The guard lamp providing night security for people is installed outdoors and exposed to the natural factors causing secular ageing and the people's vandalism, etc., thus it is prone to get troubles in function. In fact, the guard lamps has been left without considering the fundamental measures in the legislative system in spite of the loss of lives due to the electric shock accidents repetitively taking place every year. This study arouses people's attention to the risk due to the lack of management and maintenance of the guard lamp by investigating the recent technology and the actual operating conditions and some problems and countermeasures were ultimately deduced. In this process, we reflected on the various opinions through fieldwork and had a couple of consultations with field staffs, manufacturers concerned and active officers with local autonomous entities.

• Journal of Navigation and Port Research
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• v.29 no.5 s.101
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• pp.457-464
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• 2005

Database integration has been recognized as a critical issue for effective logistics service in logistics environment. However, research related to effective methodology for this have been little studied, and also, prominent achievements have yet to be suggested. The aim of this paper is to present a quantitative methodology for the identification of conflict that is a representative problem on database integration. To achieve this aim, we suggested a quantitative methodology that can efficiently fine troubles such as name conflicts when schema integration, based on the level of semantic similarity between attributes and entities. And, in order to measure these semantic similarities, we used a thesaurus dictionary that proposed previous research. Finally, we presented effectiveness of the proposed methodology through some typical examples.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.6
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• pp.1428-1442
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• 2007

Nowadays, as IT environment is changing rapidly, traditional infra system such as hardware, software, and development methodology are changing as well. Legacy system has been filled with Intellectual property such as invested budget and development period for the time of IT is developing. Many countries around the world are having troubles with how to manage the legacy system. It is time to study on a development method and the implementation of supporting tool to reuse or process the legacy system. In this paper, it proves the definition, concept and also background of legacy system by showing real market and technology trend. Developed to handle the concrete development methodology, procedure and reference. We can get more profitability and productivity advance by reuse of legacy system and maintenance cost-saving through legacy migration.

• Resources Recycling
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• v.29 no.2
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• pp.48-54
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• 2020

Korea, one of the manufacturing-oriented countries, consumes a large amount of metals in various industrial areas, but should depend on import of most of the metals from foreign countries. Also, global metal consumption amounts are increasing in relation to those of the world's reserve and production. Some metals are limitedly produced from only several centuries, which might lead to instability of the future supply of those metals. In addition, when such metals are hazardous, those may result in various environmental troubles with contamination. To resolve those issues, the recovery and the recycling of hazardous but valuable metals in industrial waste are desirable. However, there are overwhelming numbers of the metal types, waste generators, and amounts of wastes containing the metals, so it can be troublesome even to implement a preliminary status analysis to screen proper metals, wastes with the metals, and waste producers. Therefore, this study introduces the valuable metals for Korean industry, announced by public institutions, Also, a flow chart is suggested to facilitate a preliminary status analysis, using the domestic PRTR (Pollutant Release and Transfer Register) database, to screen proper waste producers containing some of hazardous but valuable metals such as nickel, cobalt, and manganese.

• The KIPS Transactions:PartD
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• v.14D no.5
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• pp.545-554
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• 2007

The user authentication and authorization in the current home network system almost works at home and home users, sometimes novice, should manage the system directly. This situation can make much of troubles, sometimes cause some suity problems. Moreover, the system costs high to build up, demands special user knowledge to maintain. In this paper, we propose the user authentication and authorization system based on remote management server to solve the problems, designed and implemented the system. To verify the system performance and function, we built a demo system for information appliances. The results of the test, the authentication and authorization function works well and reliably.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.70-77
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• 2004

In many industrial applications, an unexpected fault of induction motor drive systems can cause serious troubles such as downtime of the overall system heavy loss, and etc. As one of methods to solve such problems, this paper investigates the fault diagnosis for open-switch damages in a voltage-fed PWM inverter for induction motor drive. For the feature extraction of a fault we transform the current signals to the d-q axis and calculate mean current vectors. And then, for diagnosis of different fault patterns, we propose a clustering based diagnosis algorithm The proposed diagnostic technique is a modified ANFIS(Adaptive Neuro-Fuzzy Inference System) which uses a clustering method on the premise of general ANFIS's. Therefore, it has a small calculation and good performance. Finally, we implement the method for the diagnosis module of the inverter with MATLAB and show its usefulness.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.106-109
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• 2005

Springback is a common phenomenon in sheet metal forming, caused by the elastic recovery of the internal stresses after removal of the tooling. Recently, advanced high strength steels (AHSS) such as TRIP and DP are finding acceptance in the automotive industry because their superior strength to weight ratio can lead to improved fuel efficiency and assessed crashworthiness of vehicles. The major troubles of the automotive structural members stamped with high strength steel sheets are the tendency of the large amount of springback due to the high yield strength and the tensile strength. The amount of springback is mainly influenced by the type of the yield function and anisotropic model induced by rolling. The discrepancy of the deep drawn product comparing the data of from the product design induced by springback must be compensated at the tool design stage in order to guarantee its function and assembly with other parts. The methodology of compensation of the low shape accuracy induced by large amount of springback is developed by the expert engineer in the industry. Recently, the numerical analysis is introduced in order to predict the amount of springback and to improve the shape accuracy prior to tryout stage of press working. In this paper, the tendency of springback is evaluated with respect to the blank material. The stamping process is analyzed fur the front side member formed with AHSS sheets such as TRIP60 and DP60. The analysis procedure fully covers the binderwrap, stamping, trimming and springback process with the commercial elasto-plastic finite element code LS-DYNA3D.

• The Journal of Internal Korean Medicine
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• v.18 no.2
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• pp.177-194
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• 1997

This thesis, deduced from studying eastern and western medical records, deals with geriatric demedtia in modern society. The result were obtained as follows : 1. Dementia is a kind of chronic, progressive, degenerative disease. The chief expression and pathogenic change of the disease is organic: e.g., extensive change such as cerebrum - atrophy, and denaturalization result. in such a situation intellectual capacities and the ability to enjoy daily life deteriorate trenendously. 2. A basic internal cause of the disease is Defficiencies of the heart, liver and kidneys. An exterior cause is an Excessiveness of the 'Dam'(痰), 'Blood Stasis', 'Fung'(風) and 'Fire'. In a Western Medical view, the reason for dementia is due to the onset of Alzheimer's disease and Brain anemia resulting from Multi - infarction or some other reason. If the white - matter of the brain is injured, then dementia easily to results. 3. Disease symptoms result in troubles in intellectual functions : e.g., memory, orientation, intelligence, judgement, common sence and calculating abilities. 4. The proper therapeutic treatment depends on the causes. When the Deficiency is serious, Fortification (heart, liver. and kidney deficiency) is applied and Decrease is follow. When Excessiveness of wrong is serious, the Decrease is tried before the supplement measure is used depending on the deficiency, which generally is used together with 'Fortify Right - Decreace Wrong'. 5. If the disease wasn't caused by some mental reason, it's difficult to be cured of the disease. When the degree of the disease is light and it doesn't continue for a long time, the therapeutic treatment can block the disease's progress and improve the patient's symptoms.

• Journal of KIISE:Software and Applications
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• v.33 no.3
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• pp.316-334
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• 2006

In the traditional computing paradigm, developers design software to run in a fixed and well-defined environment. The real environment, however, is too complicated to analyze all situations perfectly. Consequently, traditional software, which is implemented only for what is wanted as input, often fails badly in real environment. As a new approach, self-adaptive software can avoid runtime failures adapting to unpredictable situations. Self-adaptive software must firstly evaluate the contextual situation to determine the need for adaptation. Existing researches do not support the abstraction mechanism for identifying contextual problem. Consequently, they can have troubles with identifying the contextual problem as the execution environment is getting complex. In addition, they cannot support the expandability for contextual problems, which software can evaluate. This paper suggests the goal-based evaluation method of contextual situation for coping with the limitations of existing researches.