• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.25-26
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• 2015

Inductive Power Transfer (IPT) method becomes more and more popular for the Electric Vehicle (EV) battery charger due to its convenience and safety in comparison with plugged-in charger. In recent years, Lithium batteries are increasingly used in EVs and Constant Current/Constant Voltage (CC/CV) charge needs to be adopted for the high efficiency charge. However, it is not easy to design the IPT Battery Charger which can charge the battery with CC/CV charge under the wide range of load variation due to the wide range of variation in its operating frequency. This paper propose a new design and control method which makes it possible to implement the CC/CV mode charge with minimum frequency variation (less than 1kHz) during all over the charge process. A 6.6kW prototype charge has been implemented and 96.1% efficiency was achieved with 20cm air gap between the coils.

• Journal of the Korean Society for Railway
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• v.13 no.1
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• pp.71-77
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• 2010

It is increasing annually that the cost for bridge Maintenance Repair & Rehabilitation (MR&R) in developed countries. Based on Intelligent Technology, Bridge Management System (BMS) is developed for optimization of Life Cycle Cost (LCC) and reliability to predict long-term bridge deteriorations. However, such data are very limited amongst all the known bridge agencies, making it difficult to reliably predict future structural performances. To alleviate this problem, an Artificial Neural Network (ANN) based Backward Prediction Model (BPM) for generating missing historical condition ratings has been developed. Its reliability has been verified using existing condition ratings from the Maryland Department of Transportation, USA. The function of the BPM is to establish the correlations between the known condition ratings and such non-bridge factors as climate and traffic volumes, which can then be used to obtain the bridge condition ratings of the missing years. Since the non-bridge factors used in the BPM can influence the variation of the bridge condition ratings, well-selected non-bridge factors are critical for the BPM to function effectively based on the minimized discrepancy rate between the BPM prediction result and existing data (deck; 6.68%, superstructure; 6.61%, substructure; 7.52%). This research is on the generation of usable historical data using Artificial Intelligence techniques to reliably predict future bridge deterioration. The outcomes (Long-term Bridge deterioration Prediction) will help bridge authorities to effectively plan maintenance strategies for obtaining the maximum benefit with limited funds.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.3214-3219
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• 2011

HONAM High Speed Railway project is under construction with the target to have 350km/h design speed from Songjeong Gwangju City to Osong. The track for the whole section of the line is scheduled to be a concrete track in order to decrease total life cycle cost (LCC) according to the decrease of track destruction. However, the study on the related parts to increase the train speed up to 400km/h is on going in order to strength the competitiveness of high speed railway. On this study, the stress of track has been analyzed according to the concrete track design method of Eisenmann using equivalent depth theory proposed by Odemark for behavior analysis of concrete track on track bed, which is having embankment deformation characteristics by train load. The behavior analysis of track is performed to analyze the stress of track bed layer and track according to the variation of design load and train speed. And also, the characteristics of concrete track have been figured out by analyzing the parameter according to the thickness of track bed layer.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.12
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• pp.1544-1553
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• 1999

Recently, ultrasonic testing techniques have been widely used in the evaluation of the quality of metal. In this experiment, six heat-treated temperature of specimen have been considered : 0, 1200, 1250, 1300, 1350 and 1387$^{\circ}C$. As heat-treated temperature increases, the grain size of stainless steel also increases and then, eventually make it destroy. In this paper, a pattern recognition method is proposed to identify the heat-treated temperature of metals by evidence accumulation based on artificial intelligence with multiple feature parameters; difference absolute mean value(DAMV), variance(VAR), mean frequency(MEANF), auto regressive model coefficient(ARC), linear cepstrum coefficient(LCC) and adaptive cepstrum vector(ACV). The grain signal pattern recognition is carried out through the evidence accumulation procedure using the distances measured with reference parameters. Especially ACV is superior to the other parameters. The results (96% successful pattern classification) are presented to support the feasibility of the suggested approach for ultrasonic grain signal pattern recognition.

• Journal of the Korea Institute of Building Construction
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• v.2 no.2
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• pp.134-143
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• 2002

The purposes of this research are to use the buildings efficiently and long, save energies, make the cozy and comfortable environment of residential and living spaces, rearrange the related acts for easy implementation of remodeling, and activate the government's support programs so as to make remodeling activated in a safe mode. The scope and methodology of this research include the review of existing literatures and data on remodeling, census on apartment residents, influence factors, and the development of methods for activation of building remodeling and strengthening of safety management, like activation measures, licensing and ordering regulation updates, etc regarding the remodeling. Safety inspection and in-depth inspection before and after remodeling should be regulated. The construction materials for remodeling should be light weighted and the construction methods which can minimize the impact and vibration during construction should be selected. The improvement of regulation on the remodeling contractor qualification and order method should be updated. If the remodeling is activated and safety management is reinforced by the suggested measures, solving of lack of house, prevention of abuse of resources, and improvement of residential environment could be accomplished rationally.

• Journal of the Korea Institute of Building Construction
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• v.8 no.6
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• pp.155-160
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• 2008

The BTL project, 4 years since its operation. has benchmarked the PFI Project in Japan and has been introduced. Given the evaluation step to select a preferred bidder, in a technological factor, the basic plans are corrected and complemented, whereas in a price factor, the low price bidding system is being enforced. There is concern that how to select preferred bidders and how to operate project costs during operation and management period may be problematic. Thus, in this study, using the Analytic Hierarchy Process, the method of deciding the priority to select preferred bidders in an early stage of the project and the evaluation model to evaluate the validity of BTL project expenses in process of project enforcement are established. Targeting the group composed of experts who have experiences in the BTL project. Then, the levelling of evaluation factors and grouping have been carried out as following : LCC analysis and disbursement for government including two more detailed factors.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.2
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• pp.331-336
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• 2018

In this paper, the life cycle cost of the auxiliary power unit in the conventional 8200 series electric locomotive is evaluated and an effective life cycle cost reduction method is sought. For this, a life cycle cost evaluation model was proposed using IEC 60300-3-3 standard. As a result of analysis, material cost which accounted for a large percentage of preventive maintenance cost, accounted for 64% of total cost, and breakdown maintenance cost was as high as 27%. Except for the cost of preventive maintenance, the breakdown maintenance cost ratio was the highest. In order to reduce the LCC of the auxiliary power unit(APU) of the 8200 series in the future, it is necessary to reduce the material cost in case of development and to secure the high reliability according to the parts manufacturing so as to minimize the maintenance cost.

• Journal of Korean Library and Information Science Society
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• v.35 no.2
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• pp.135-154
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• 2004

This study was investigated to the geographical categories and arrangement of library classifications and public organizations in ender to understand the geographical category comprehension and canon from the north-west to south-east in Korean library classification and then to develop a Korean geographical classification system Research method was the examination of different type of library classification (DDC, NDC, LCC) and geographical categorizations of the public organizations. The results show that there was not a principle of categorization and arrangement for geographical information. This study proposes to the three hierarchical structures and radial category arrangement from center-area to side area for developing Km geographical classification.

• KIEAE Journal
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• v.15 no.3
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• pp.15-20
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• 2015

Purpose: Suggesting a working prototype of a kinetic light shelf unit and revealing its energy efficiency by a series of building performance simulations were presented. Recently, kinetic building envelope has been an emerging technology as an innovative way to control exterior building environment, but products from many researches about the facade could not been reached to the industrialization so far. That is because its initial installation, operation and maintenance costs are still too high to use for the practical field, although buildings using kinetic envelopes could decrease their energy consumption significantly. This narrow point of view needs to be reconsidered, since buildings require great amount of energies to run their functions through the whole life and using better building components can lead to achieve much more benefits in aspects of the lifecycle cost (LCC). Method: A series of certified simulation tools like Ecotect and Green Building Studio that are normally used for researches and developments in the field of architecture were utilized. Result: Based on simulation analyses, the result of the study has showed that the proposed system definitely has adaptability to the professions and positively shows practicability as advanced integrative building envelopes with renewable energy association.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.292-298
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• 2010

Recently, with the beginning of the commercial operation of high-speed railway, there have been a number of changes in track structure fields. Also, it is expected that the development and introduction of new technology will be increased afterwards. However, it accompanies a lot of risk to install new track structures of which performance and safety are not verified on permanent ways with high traffic density. Therefore, to minimize the risk and enhance the adoption of new technology, it is required to develop a systemic verification system for track structure. To do this, in this paper, main contents of a draft of guidelines for track structure verification, and main issues in debate such as criteria and method for verification, test conditions and test periods are discussed. Also, a process to choose a most appropriate one for a specific project out of proven track structures by the above verification system, the selection process by the technical investigation committee and the VE process to analyze the economical and maintenance aspects based on LCC concept in Korea Rail Network Authority is introduced.