• International conference on construction engineering and project management
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• 2009.05a
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• pp.1433-1439
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• 2009

Best value is the ultimate goal of the owner and can thus have diverse meanings according to the project characteristic, owner's purpose, user groups' payment capability, etc.. Recently, resettlement problems of the marginalized members in the urban regeneration area have been issued in Korea because they have no capability to purchase (or lease) redeveloped housing (or apartment). It means that a minimized production cost for reducing supply price of housing is a key factor in establishing the best value of the marginalized members. The lowest-price bidding system serves the purpose of ensuring a minimized production cost, but due to the low-cost investments, it creates various problems, such as sloppy construction, lowered quality, an increased LCC, and worsening profitability for builders. Thus, to help them resettle, it is necessary to supply affordable housing geared towards a certain appropriate quality and minimum construction costs. Towards this end, this study aimed to propose a cost reduction bidding system based on a technical proposal. The proposed technical-proposal-based cost reduction bidding system consists of the following components: work-unit-based, project-unit-based, and construction-period-reducing technical proposals. These components are evaluated to select the best bidder for a given project. The technical proposal based cost reduction bidding system proposed herein is expected to provide facilities with appropriate supply prices and appropriate quality levels, to bolster the technological competitiveness of builders.

• Journal of the Korean Society of Safety
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• v.22 no.5
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• pp.1-6
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• 2007

Vibro-impacts in manual transmissions result due to several nonlinearities such as multi-staged clutch characteristics and gear backlashes. For the sake of understanding the torsional system, one specific manual transmission with front engine and front wheel drive configuration is investigated with a linear model under the several assumptions substituting the nonlinear factors. First, this system is examined with the mathematical approaches by expressing the governing equations to find out the torsional motions. Second, this system is analyzed using the linear model in order to understand its modal and frequency response characteristics using eigensolution method and the FRF(Frequency Responses Function) analysis. Third, with the given results from the eigensolutions, several mode shapes are investigated related to the torsional motion characteristics. Fourth, the system characteristics with the FRFs are studied with the basic approach, with which the several key parameters will be suggested based upon the results in the further studies.

• Journal of Advanced Marine Engineering and Technology
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• v.10 no.3
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• pp.94-106
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• 1986

Since the oil shock of '70s the engine makers have developed new types of diesel engine with low fuel consumption. There is an obvious tendency towards the use of poorer quality fuels, such as the residual oil from chemical processes of refinery. The shaft driving generators is also widely adopted on behalf of the auxiliary diesel engines, which are driving on the expensive diesel oil and have high fuel oil consumption rates, and some mania propulsion diesel engines are equipped with reduction gear systems to get better propulsive efficiency by slower propeller revolutions. The propulsion shafting system equipped with the shaft driving generator or the geared diesel engine shafting system has flexible couplings, and it requires extensive investigations of the torsional vibration and torque fluctuation in order to ensure the acceptable operation range in service. The characteristics of misfiring must be especially examined for the high viscosity fuels to be used. Both torsional vibration and fluctuating torque resulted from misfiring, should be examined for thier effects on the flexible coupling and propulsion shafting system. This paper is to investigate and solve the above mentioned problems which must be predicted on the design-stage of marine propulsion shafting system. A computer program is developed to calculate the indicated diagram, fluctating torque and torsional vibration for both normal and misfiring conditions.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.1
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• pp.35-39
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• 2010

The IT project for power plants initiated domestically in 2005 necessitates the power equipment facility and the controllers for those to be sufficiently adaptable for automation system for power substations. This implies that the power plants using power equipments must be developed to satisfy the IEC61850 standards. The IEC61850 communication standards that all power equipment and facility and controllers installed in automation system for power substations must follow has had its Parts 3 and Part 4 established as international standard in January 2002 and Part 10 in May 2005, the last to become international standard. Hence all separate parts of the original IEC61850 standard came to be established as international standards. As a consequence, after 2005, in most power substations around the world the IEC61850 standard is being applied and the prominent makers are geared towards manufacturing products to the IEC61850 standard. The IEC61850 is being recognized as an essential standard that must be applied to not only power substations but for automation of power systems and communication systems. In this research, the Gateway device that connects current SCADA system and IEC61580 based system has been domesticated with Korea‘s own technology and extensive testing was carried out in order to obtain confidence in its performance.

• English Language & Literature Teaching
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• v.12 no.1
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• pp.131-158
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• 2006

The purpose of the present study is to explore an effective way of teaching English vocabulary which is geared toward improving students' English communicative competence. This study focuses on English verbs, which may be followed by patterns according to subcategorization. Learning verbs must include learning about patterns as well as meaning in order to improve the ability to use verbs receptively and productively, or communicative competence. On the basis of the language progression proposed by Willis (2003), a teaching strategy which helps learners learn English verb patterns effectively and systematically was proposed. The effect of the teaching strategy was investigated. The subjects of the experimental group who learned English verb patterns intentionally through the teaching strategy proposed by this study significantly improved themselves in the ability to use them receptively and productively. This result shows that the teaching strategy including improvisation, recognition, rehearsal, system building, exploration and consolidation is helpful to improving communicative competence.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.756-760
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• 2001

Two different designs of permanent magnet motors as direct wheel-set drive for the German high speed train ICE 3 are designed, one with surface mounted magnets (SM) and one with buried rotor magnets (BM). The surface magnet motor has $17\%$ less mass and a slightly higher efficiency and was therefore chosen for further investigations. Compared with the conventional drive system of the ICE 3, consisting of geared inverter fed induction machines, the gearless permanent magnet direct drive yields about $16\%$ lower losses. This calculation is based on the route parameters of the high speed track between Frankfurt/Main and Cologne in Germany, which is currently under construction.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.552-558
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• 2001

When operating lathe gear box which is equipped with geared transmission, it sometimes generates loud noise and excessive vibrations. In order to identify their causes, in this study, torsional and lateral vibration characteristics including critical speeds of the gear transmission system are firstly analyzed using lumped parameter models. Natural frequencies and mode shapes of the gear box structure are also analyzed by using the modal test. Furthermore, measured vibration and noise signals during operations are analyzed and compared with theoretical analysis results. After all, it is concluded that the primary cause of the excessive noise and vibrations is the resonance between gear meshing frequency including its side bands, the frequencies of shaft bending and torsional vibrations, and the natural frequencies of the gear box structure. Consequently the noise and vibration levels are greatly reduced by avoiding resonance between the natural frequencies and gear meshing frequencies through the rearrangement of the gears on the transmission shaft without any gear ratio change.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.404-407
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• 1995

Teleoperating system has been developed for several decades, and many control schemes for it have been suggested. But the implementation for real application needs very simple but effective controller. In this paper, an advanced control scheme for this purpose is suggested, which is the combination of a modified internal model controller and variable filter for force reflection. And we verify the effectiveness of the proposed scheme through the experiment. We use PUMA-560 as the slave robot, which is operated by velocity servo loop with geared motor. Both the responses of free motion and contact motion are shown.

• Research in Mathematical Education
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• v.6 no.2
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• pp.123-133
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• 2002

The authors examined a college mathematics professor's change process in teaching practice by analyzing the teacher's reflective journal. Her change engaged cooperative learning method in a college Algebra course and was geared toward the reform-oriented methods. The change processes were revealed as a bumpy road that was full of struggles and challenges to both the teacher and students. The analysis also showed that a reflective journey needed a proper means and support system from a teacher's environment such as institution. This research clearly showed that brining a genuine change in teaching practice toward a broad educational goal was a combined effort among the participants of education.

• IMMUNE NETWORK
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• v.16 no.5
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• pp.261-270
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• 2016

The human immune system has evolved to fight against foreign pathogens. It plays a central role in the body's defense mechanism. However, the immune memory geared to fight off a previously recognized pathogen, tends to remember an original form of the pathogen when a variant form subsequently invades. This has been termed 'original antigenic sin'. This adverse immunological effect can alter vaccine effectiveness and sometimes cause enhanced pathogenicity or additional inflammatory responses, according to the type of pathogen and the circumstances of infection. Here we aim to give a simplified conceptual understanding of virus infection and original antigenic sin by comparing and contrasting the two examples of recurring infections such as influenza and dengue viruses in humans.