• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.6 s.40
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• pp.55-66
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• 2004

Recently, many high-rise apartment buildings using the box system, composed of only reinforced concrete walls and slabs, have been constructed. In residential buildings such as apartments, vibrations occur from various sources and these vibrations transfer to neighboring residential units through walls and slabs. It is necessary to use a refined finite element model for an accurate vibration analysis of shear wall building structures. But it would take significant amount of computational time and memory if the entire building structure were subdivided into a finer mesh. Therefore, an efficient analytical method, which has only translational DOFs perpendicular to walls or slabs by the matrix condensation technique, is proposed in this study to obtain accurate results in significantly reduced computational time. If all of the DOFs except those perpendicular to walls or slabs in the shear wall structure eliminated using the matrix condensation technique at a time, the computational time for the matrix condensation would be significant. Thus, the modeling technique using super elements and substructuring technique is proposed to reduce the computational time for the matrix condensation. Dynamic analysis of 3-story and 5-story shear wall example structures were performed to verify the efficiency and accuracy of the proposed method. It was confirmed that the proposed method can provide the results with outstanding accuracy requiring significantly reduced computational time and memory.

• Journal of Distribution Research
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• v.13 no.4
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• pp.71-95
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• 2008

Transaction between industrial suppliers and their buyers in business markets increasingly take place in the form of long-tenn business relationships. These relationships are governed through formal or informal agreements. Dynamic business markets are also forcing B2B marketers to create flexibility in their firms. However, buyers are bound in their rationality and find it impossible to contemplate all possible future contingencies. The more formal and detailed the contracts they conclude, the likelier it becomes that at least one buyer is going to perceive a need to adjust the initial agreement as environmental events unfold. In this case, the actor relies upon industrial supplier's competence. Our study purpose is to examine the consequences of supplier's competence on the industrial customer-supplier long-tenn relationship. Antecedent variables of supplier competence include R&D, flexibility, brand asset, market sensing, and customer support service. We presented a comprehensive constructive model consisting of components of supplier's competence and the antecedent factors. Research hypotheses were developed and data were gathered from respondents who work in the cosmetics industry. The results discussed here represent a first step towards a better understanding of the role of supplier competence in the B-to-B cosmetics industry. Managerial implications and the limitations of this research were also discussed.

• KDI Journal of Economic Policy
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• v.28 no.2
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• pp.131-177
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• 2006

This paper examines a simultaneous determination of corporate control mechanisms, and its effects on firm performance. The corporate control mechanisms considered include the following; insider shareholding, institutional shareholding, the board of directors, dividend policy, and capital structure. This paper applies a simultaneous equation methodology and investigates the interdependence among the corporate control mechanisms. In the first part, the paper finds that firm-level variations of control mechanisms are large across time although average variations are relatively small. These variations are related to one another, which is confirmed by Granger causality test based on dynamic panel autoregression model. More specifically insider shareholding, institutional shareholding and outside director ratio cause each other. With regard to interdependence among the control mechanisms, 2SLS(two stage least squares) regression results show that insider shareholding and institutional shareholding are substitutes while institutional shareholding acts as complements to the ratio of outside members in the board of directors. Then in the second part, the paper examines the relationship between firm performance and corporate governance. Firm performance, measured by Tobin's Q, has a positive association with leverage ratio while that has a negative relation to outside director ratio. This suggests that there may be a room for reforming corporate governance in Korea. Specifically it is necessary to enhance the independence of the outside directors.

• Journal of the Korea Concrete Institute
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• v.22 no.3
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• pp.409-417
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• 2010

This paper discusses a series of experiments including material improvement in order to ensure quality of grouting for the post-tensioned structure. In prestressed concrete, grouting refers to the construction procedure of filling empty space of duct enclosing with strands using cementitious material, To date, adequate quality control of the grouting has not been established in Korea because the relationship between the grouting and durability of post-tensioned structure is not well-recognized. The Korean standard does not consider the important material characteristic, wick effect, which is caused by strands in the ducts and current standard testing method unlikely quantify reasonable material segregation. As a result, the grout material, which meets the current material standards, may exhibit excessive bleeding water or shrinkage during construction. In this study, international codes and standards related to grouting were surveyed. The ratio of constituents and novel admixtures were suggested to meet equivalently with these standards. Performance of this enhanced grout was compared to common domestic grout using the international standard testing method. A series of mock-up specimens considering geometry of PC beam was constructed and grout flow pattern was observed as the grout was injected. It was observed that the grouting performance was highly influenced by material properties and filling characteristic can be varied depending on geometry of ducts.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.12 no.3
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• pp.139-148
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• 2000

In this paper, the interaction of oblique incident waves with a bottom-mounted and fluid-filled flexible membrane structure is investigated in the frame of linear hydro-elastic theory. The static shape of a membrane structure containing the fluid of a specific density is initially unknown and must be calculated before the hydrodynamic analysis. To solve hydrodynamic problem, the fluid domain is divided into the inner and outer region. The inner solution based on discrete membrane dynamic model and simple-source distribution over the entire fluid boundaries is matched to the outer solution ba~ed on an eigenfunction expansion method. The numerical results were compared to a series of Ohyama's experimental results. The measured reflection and tran¬smission coefficients reasonably follow the trend of predicted values. Using the computer program developed, the performance of a bottom-mounted and fluid-filled flexible membrane strocture is tested with various system parameters (membrane shape, internal pressure, density ratio) and wave characteristics (wave frequencies, incident wave angle). It is found that a bottom-mounted and fluid-filled flexible membrane structure can be an effel;tive wave barrier if properly designed.

• Environmental and Resource Economics Review
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• v.25 no.3
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• pp.449-470
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• 2016

This paper analyzes the effects of nuclear power generation on industrial growth in using the data of 22 manufacturing sectors in 14 nuclear power countries. The hypothesis that the change in the proportion of nuclear power generation in total electricity generation affects industrial value-added and industrial output through industrial electricity price reduction was tested using the dynamic panel data model. First, it was estimated that the increase in nuclear power generation by a 1% leads to a 0.8% reduction in electricity price. The results indicate that when nuclear power generation increased by a 1% point, industrial value-added and output increased by 0.16% and 0.23%,respectively, in the short-run and by 0.51% and 0.85%, respectively, in the long-run. It was also inferred that the effect of nuclear generation on industrial competitiveness working through electricity price reduction rely on institutional settings in the electricity markets. That is, the competitive effect is greater in the countries such as U.K and Japan where electricity price is high and price volatility is large. Meanwhile, in Germany which has pursued phasing out nuclear power, industrial competitiveness is promoted through stable electricity supply.

• Journal of Navigation and Port Research
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• v.36 no.6
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• pp.521-526
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• 2012

More efficient and effective volume management of trade cargo is recently requested due to FTA with foreign country. Above all, the grain is the main cargo needed in Korean food life and was appointed as the core trade cargo during FTA. This study is aimed to forecast future demands of grain volumes which are handled at Incheon port because most of the grain volumes are traded at Incheon port in Korea. System Dynamics (SD) was used for forecasting as the methodology. Also, population, yearly grain consumption per a man, GDP, GRDP, exchange rate, and BDI were used as the factors that influence grain volumes. Simulation duration was from 2000 to 2020 and real data was used from 2000 to 2007. According to the simulation, 2020's grain volumes at Incheon port were forecasted to be about 2 million tons and grain volumes handled at Incheon port were continuously reduced. In order to measure accuracy of the simulation, this study implemented MAPE analysis. And after the implementation, the simulation was decided as a much more accurate model because MAPE value was calculated to be 6.3%. This study respectively examined factors using the sensitivity analysis. As a result, in terms of the effects on grain volume in Incheon Port, the population factor is most significant and exchange rate factor is the least.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.1
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• pp.9-26
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• 2005

In the pursuit of ever higher levels of performance, recent computer systems have made use of deep pipeline, dynamic scheduling and multi-issue superscalar processor technologies. In this situations, branch prediction schemes are an essential part of modem microarchitectures because the penalty for a branch misprediction increases as pipelines deepen and the number of instructions issued per cycle increases. In this paper, we propose a novel branch prediction scheme, direction-gshare(d-gshare), to improve the prediction accuracy. At first, we model a neural network with the components that possibly affect the branch prediction accuracy, and analyze the variation of their weights based on the neural network information. Then, we newly add the component that has a high weight value to an original gshare scheme. We simulate our branch prediction scheme using Simple Scalar, a powerful event-driven simulator, and analyze the simulation results. Our results show that, compared to bimodal, two-level adaptive and gshare predictor, direction-gshare predictor(d-gshare. 3) outperforms, without additional hardware costs, by up to 4.1% and 1.5% in average for the default mont of embedded direction, and 11.8% in maximum and 3.7% in average for the optimal one.

• Journal of Cadastre & Land InformatiX
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• v.47 no.2
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• pp.159-174
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• 2017

The long-term imbalances between supply and demand in office market can weaken urban growth since excessive supply of offices led to office market instability and excessive demand of offices weakens growth of urban industry. Recently, there have been a lot of new large-scale supplies, which increased volatility in Seoul office market. Nevertheless, new supply of Seoul office has not been fully examined. Given this, the focus of this article was on confirming the influences of profitability, replacement cost, and demand on new office supplies in Seoul. In examining those influences, another focus was on their relative influences over time. For these purposes, we analyzed quarterly data of Seoul office market between 2003 and 2015 using a vector error correction model (VECM). As a result, in terms of the influences on the current new supply, the impact of supply before the first quarter was negative, while that of office employment before the first quarter was positive. Also, that of interest rate before the second quarter was positive, while those of cap rate before the first quarter and cap rate before the second quarter were negative. Based on the findings, it is suggested that prediction models on Seoul offices need to be developed considering the influences of profitability, replacement cost, and demand on new office supplies in Seoul.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.5
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• pp.571-577
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• 2012

In this study, a small movable batch treatment system for dredging soil deposited in a rain water tube is proposed; further, a vacuum silo sorting separation device with a vacuum silo, first-stage sorting separator, and conveyor is designed. The vacuum silo sorting separation device also consists of a storage tank, transferring screw, vacuum gate, screen bar, screen bar cleaner, and vacuum discharging device. In view of the fact that the flow of drawn air in the storage tank is a major factor influencing the sorting separation performance, the optimum shape of the tank is determined by CFD flow analysis. In addition, by using CAE structure analysis, the safety of a storage tank made of boards is examined. The specifications of the vacuum silo sorting separation device are determined by conducting mechanical and dynamic simulations of the driving mechanism of the vacuum silo sorting separation device through 3D-CAD modeling. Following this study, we will design a drum-screen-type second sorter, a decanter-type dehydration device, and waste water tank and pump as a secondary device. Further, on the basis of this design, we will construct a prototype model and carry out a field test.