• Journal of The Korean Digital Architecture Interior Association
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• 제10권2호
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• pp.13-20
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• 2010

Uncertainty in housing price fluctuation has great impact on the overall economy due to importance of housing market as both place of residence and investment target. Therefore, estimating housing market condition is a highly important task in terms of setting national policy. Primary indicator of the housing market is a ratio between rent and transaction price of housing. The research explores dynamic relationships between Rent-Transaction price ratio, housing transaction price and jeonse rental price, using Vector Autoregressive Model, in order to demonstrate significance of shifting rent-transaction price that is subject to changes in housing transaction and housing rental market. The research applied housing transaction price index and housing rental price index as an indicator to measure transaction and rental price of housing. The price index and data for price ratio was derived from statistical data of the Kookmin Bank. The time-series data contains monthly data ranging between January 1999 and November 2009; the data was log transformed to convert to level variable. The analysis result suggests that the rising ratio between rent-transaction price of housing should be interpreted as a precursor for rise of housing transaction price, rather than judging as a mere indicator of a current trend.

• Journal of Environmental Policy
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• 제2권2호
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• pp.17-40
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• 2003

The objective of this paper is to formulate strategies and action programs for developing sustainable agriculture in Korea. There is increasing evidence that agriculture has been preoccupied with increasing productivity much to the detriment of environmental degradation. The issue of increasing agricultural productivity so as not to undermine the environment is a difficult task. In reality, there are many definitions of sustainable agriculture and sustainable agricultural development. In this paper, sustainable agriculture is defined by its ability to ensure future supplies of agricultural products at acceptable economic and environmental costs to the society. Sustainable agriculture development refers to the optimal level of interaction among the three dimensions - the environmental, the economic and the social - through dynamic and adaptive processes of trade-off. In order to formulate the strategies for developing sustainable agriculture, three stage approaches such as strategic analysis, strategic choice, and strategic implementation are employed. The basic framework for strategies of sustainable agriculture development consists of five steps such as vision, targets, principles, action plan and policy instruments. The major action plans for activating formulated strategies are suggested as integrating agricultural and environmental policy measures, establishing the system of optimal agri-environmental resources management practices, establishing safe and high quality product system and its effective marketing system, increasing the R&D investment for developing sustainable agro-technology, developing indicators for measuring sustainable agricultural development, and taking a share in related roles for all parties including farmers, consumers, policy makers, researchers and NGOs.

• Proceedings of the KSME Conference
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1854-1858
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• 2007

The reliability assurance with respect to the test procedure and results of the out-pile mechanical performance test for the nuclear fuel assembly is an essential task to assure the test quality and to get a permission for fuel loading into the commercial reactor core. For the case of vibration test, which is carried out to obtain basic dynamic characteristics of the fuel assembly, proper management and appropriate calibration of instruments and devices used in the test, various efforts to minimize the possible error during the test and signal acquisition process are needed. Additionally, the deep understanding both of the theoretical assumption and simplification cation for the signal processing/modal analysis and of the functions of the devices used in the test were highly required. Finally, to verify the test result to represent the accurate natural characteristics of the structure, the proper correlation analysis between the theoretical and experimental method has to be carried out. In this study, the overall procedure and result of lateral vibration test for the fuel assembly's mechanical characterization were briefly introduced. A series of measures to assure and improve the reliability of the vibration test were discussed.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• 제18권4호
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• pp.400-410
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• 2008

Reduction of structure-borne noise in the compartment of a car is an important task in automotive engineering. Many methods which analyze noise transfer path have been generally used for structure-borne noise. These methods are useful in solving particular problem but do not quantify the effectiveness of vibration isolation for each isolator of a vehicle. To quantify the effectiveness of vibration isolation, the vibrational power flow measurement has been used for a simple isolation system or a laboratory based isolation system. This paper identifies the transfer path of booming noise in a SUV. The powertrain used for test has a in-line 4cylinder engine and 5-shift auto-transmission. This powertrain is transversely supported by four isolators. We calculated the energy flow throughout four isolator by the measurement of power flow and the contribution of energy flow at each isolator.

• Smart Structures and Systems
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• 제10권4_5호
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• pp.331-351
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• 2012

In this study an output-only system identification technique for civil structures under ambient vibrations is carried out, mainly focused on using the Stochastic Subspace Identification (SSI) based algorithms. A newly developed signal processing technique, called Singular Spectrum Analysis (SSA), capable to smooth a noisy signal, is adopted for preprocessing the measurement data. An SSA-based SSI algorithm with the aim of finding accurate and true modal parameters is developed through stabilization diagram which is constructed by plotting the identified system poles with increasing the size of data matrix. First, comparative study between different approaches, with and without using SSA to pre-process the data, on determining the model order and selecting the true system poles is examined in this study through numerical simulation. Finally, application of the proposed system identification task to the real large scale structure: Canton Tower, a benchmark problem for structural health monitoring of high-rise slender structures, using SSA-based SSI algorithm is carried out to extract the dynamic characteristics of the tower from output-only measurements.

• Earthquakes and Structures
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• 제14권5호
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• pp.389-398
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• 2018

The seismic isolation system makes a structure isolated from ground motions to protect the structure from seismic events. Seismic isolation techniques have been implemented in full-scale buildings and bridges because of their simplicity, economic effectiveness, inherent stability and reliability. As for the responses of an isolated structure due to seismic events, it is well known that the most uncertain aspects are the seismic loading itself and structural properties. Due to the randomness of earthquakes and uncertainty of structures, seismic response distributions of an isolated structure are needed when evaluating the seismic fragility assessment (or probabilistic seismic safety assessment) of an isolated structure. Seismic response time histories are useful and often essential elements in its design or evaluation stage. Thus, a large number of non-linear dynamic analyses should be performed to evaluate the seismic performance of an isolated structure. However, it is a monumental task to gather the design or evaluation information of the isolated structure from too many seismic analyses, which is impractical. In this paper, a new methodology that can evaluate the seismic fragility assessment of an isolated structure is proposed by using stochastic response database, which is a device that can estimate the seismic response distributions of an isolated structure without any seismic response analyses. The seismic fragility assessment of the isolated nuclear power plant is performed using the proposed methodology. The proposed methodology is able to evaluate the seismic performance of isolated structures effectively and reduce the computational efforts tremendously.

• Journal of the Korean Society for Advanced Composite Structures
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• 제6권2호
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• pp.97-104
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• 2015

Compared with a strong axial rigidity due to large intial tension, cable has a weak laterally flexural rigidity. A variety of dynamic loads such as traffic loads and wind loads etc. cause the cables to vibrate significantly and affect the mechanical properties and the performance of cables. Therefore, vibration reduction design is an urgent task to control the vibration of cable-supported bridges. Because a various kind of dampers have shown to reduce the amplitude and duration time of vibration of cable from measured date in field test, damper can be considered that it is effective device significantly to reduce the amplitude and duration time in vibration of cable. Vibration characteristics of cable can change according to manufacturing method and type of established form, and damper has been designed according to distribution of natural frequencies and vibration modes. In this study, numerical analysis is used to show the reduction effects of vibrations and present the design of damper for vibration reduction of cable.

• Journal of the Ergonomics Society of Korea
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• 제24권4호
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• pp.15-21
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• 2005

Use of a glove made of materials with a low elasticity decreases the performance of the hand such as agility, dexterity, range of motion, and grip strength. The present study examined if the adverse effects of a low-elastic glove can be reduced by a design which accommodates the changes of hand surface lengths by hand motion. Two glove designs which provide patches of elastic cloth and pleats at the finger joints and knuckle were developed by considering the hand surface length changes, and then compared with two conditions(bare hand and conventional glove design that does not consider the dynamic characteristics of the hand dimensions) in terms of completion time in peg board insertion task, maximum grip strength, discomfort in hand motion, discomfort in force exertion, and overall discomfort by 24 right-handed participants. The test results confirmed that wearing of a glove significantly reduced the agility and grip strength capability of the hand and indicated that the novel designs were effective to lessen the performance decreases compared to the conventional design. Also, of the glove designs, the pleat glove design was found most preferred for both better hand performance and less subjective discomfort.

• English Language & Literature Teaching
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• 제11권3호
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• pp.89-112
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• 2005

This study investigated the effects of collocation-based vocabulary instruction for the experimental group (G2). It was compared to the traditional wordlist-based vocabulary instruction for the control group (G1). This results reflect the development of low level high school EFL learners' vocabulary learning strategy use and the positive change in the affective domain. In the analysis of the survey responses, G1 and G2 did not differ significantly on the first questionnaire. They did, however, differ significantly on the second questionnaire. G2 used more strategies to discover and to consolidate the meaning of the words by means of combining words. In terms of the affective domain, G2 participated more actively in the learning activities, which had a significant effect on vocabulary growth, memory, self-confidence, motivation, and cooperative learning. This is attributable to the fact that G2 was more inquisitive, interested, challenged, participatory, cooperative, and attentive than G1 in performing the vocabulary task activities. Moreover, the data collected from the questionnaire showed that G2 performed more interactive and dynamic activities in solving the given tasks.

• English Language & Literature Teaching
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• 제11권3호
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• pp.71-87
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• 2005

The role of interaction in second language (L2) classrooms has been examined from different angles, ranging from early studies of foreigner talk to the studies of the teacher- and task-based talk. However, most of the research on L2 classroom interaction has been based on a traditional psycholinguistic view of language and learning, failing to reconceptualize a broad and holistic understanding of L2 learning. Currently, many researchers have attempted to explore and describe classroom interaction in L2 classrooms from a sociocultural perspective. The purpose of this paper is to discuss Vygotsky's theoretical framework in terms of L2 classroom interaction and research from a sociocultural perspective, by describing three key concepts (zone of proximal development, private speech, and activity theory) in Vygotsky's theoretical framework and relating them to L2 classroom interaction. The results demonstrated the importance of social interaction for second language acquisition with the review of the related research study. It was also suggested that the dynamic and interactive processes of second language learning in the classroom should be valued by L2 researchers as well as L2 teachers. Finally, implications for the concepts for L2 classroom research and pedagogy are presented in the conclusion.