• Journal of the Korean Regional Science Association
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• v.14 no.1
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• pp.1-20
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• 1998

In this paper, the authors studied a comprehensive study of national physical distribution costs used here was originally developed by J. L. Heskett(1962) and modified in Korean context by Oh-Kyung Kwon(1997). Using this method the authors calculated national physical distribution costs in Korea from 1984 to 1996. Unlke the major industrialized countries, national physical distribution costs in Korea showed continuous increasing trend in every senses. Using this time series data on physical distribution costs, we analysis the inefficiencies in the physical distribution and figured out the sources of these inefficiencies. The major sources of increasing physical distribution costs in Korea were (1) increasing traffic congestion measured by number of automobiles per road-kilometer, (2) increasing real wages, and (3) high interest rates. Especially, alternatives adopted by firms facing increasing traffic congestion were buying more vehicles, which in turn caused more serious congestion ever. This inefficient cycle in physical distribution area should be cut somehow in order to restore national competitiveness of Korean frims by reducing physical distributins costs.

• Proceedings of the Technology Innovation Conference
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• 2004.02a
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• pp.83-107
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• 2004

This study investigates how and through which channels R&D activities influences the national economy, using a macro-econometric model. The macro-econometric model in this study includes 24 behavioral equations and 25 identities and was estimated using the annual data. From a simulation analysis, it is shown that the R&D investment has a permanent effect on real variables; lowering prices, wages and interest rates, and increasing potential and real GDP in the long run. It is noted that the national account was recalculated to avoid double-counting in estimation of R&D stocks.

• Journal of Chest Surgery
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• v.26 no.11
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• pp.881-885
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• 1993

In the last few years there has been a resurgenceof interest in in-situ saphenous vein arterial bypass for lower extremity revascularization because of improved patency rates. we performed 1 in situ bypass oreration using the intraluminal valve-disruption tecnique. A 65-year-old female who had ztherosclerotic obstruction in the superficial and popliteal arteries underwent in situ saphenous vein arterial bypass. After harvesting of saphenous vein, we used LeMaitre retrograde valvulotome for valve-disruption technique. Completion of the arterrigraphy was performed to evaluate bothh the anastomoses. The two side brances were all ligated. In situ saphenous vein arterial bypass has become the procedure of choice for distal reconstruction in severely ischemic lower extremities because of improved long-term patency compared with reversed-saphenous vein bypass procedure.

• KDI Journal of Economic Policy
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• v.40 no.3
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• pp.69-89
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• 2018

We study whether a default option attached to non-recourse mortgages improves borrowers' surplus from mortgage financing. By defaulting on mortgage debt, borrowers can save their non-collateralized income from being foreclosed. In exchange, borrowers must forgo non-monetary surplus from retaining any collateral. Banks may charge a high mortgage rate due to increased default rates. We find that the interest rate of non-recourse mortgage decreases with the borrower's surplus from home ownership. Moreover, non-recourse mortgages benefit only borrowers who deem housing property as an investment asset. Hence, the transition to a non-recourse mortgage is detrimental to welfare if the borrower enjoys a large surplus from home ownership. Although the borrower privately knows how much surplus she enjoys from home ownership, a menu of non-recourse mortgage contracts may exist, yielding a separating equilibrium without information rent.

• Management & Information Systems Review
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• v.20
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• pp.85-113
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• 2007

This study came up with a comparison analysis between the average results of Whole National Cooperatives and Kyonggi cooperatives from 2000 to 2005. 15 Kyonggi Agricultural Cooperatives which are nearly the same in the aspects of size and local conditions, - Songpo, Shindo, Ilsan, Jido, Migum, Dongduchon, Bucheon, Ojeong, Naksaeng, Seongnam, Suwon, Kunja, Banweol, Ansan, Suji- are selected as comparable ones while the cooperatives of Kwangmyung, Kungpo, Anyang, Euiwang represent as Kwachon neighborhood cooperatives. The analysis result proposes some desirable ideas to activate the business of local cooperatives as follows. First, the top limit of allotting profits seem to require having the lower adjustment which takes into account the interest rates. Second, the system allotting the profits in proportion to the record of the use should be improved. Third, In order to activate the business of semi-members, allotting profit system in proportion to the record of the use should be established.

• Communications for Statistical Applications and Methods
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• v.24 no.6
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• pp.543-559
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• 2017

Tree-based regression and classification ensembles form a standard part of the data-science toolkit. Many commonly used methods take an algorithmic view, proposing greedy methods for constructing decision trees; examples include the classification and regression trees algorithm, boosted decision trees, and random forests. Recent history has seen a surge of interest in Bayesian techniques for constructing decision tree ensembles, with these methods frequently outperforming their algorithmic counterparts. The goal of this article is to survey the landscape surrounding Bayesian decision tree methods, and to discuss recent modeling and computational developments. We provide connections between Bayesian tree-based methods and existing machine learning techniques, and outline several recent theoretical developments establishing frequentist consistency and rates of convergence for the posterior distribution. The methodology we present is applicable for a wide variety of statistical tasks including regression, classification, modeling of count data, and many others. We illustrate the methodology on both simulated and real datasets.

• Journal of Advanced Marine Engineering and Technology
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• v.20 no.4
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• pp.43-49
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• 1996

With the recent interest in methanol as a SI engine fuel, aldehyde emissions have become a greater concern. A M-90 fueled passenger car was operated in a chassis dynamometer using FTP 75 driving cycle to examine formaldehyde emissions. Formation process of aldehyde and methods to reduce them are discussed in this paper for a SI-engine passenger car operating by M-90. Aldehyde emissions have been found to be 3 to 7 times higher from M-90 than from gasoline, while CO, NOx, THC are as low or lower than gasoline. Noble metal compositions appeared to play a role in formaldehyde and unburned methanol emission performance. For example, catalyst Pd showed better reduction of both formaldehyde and methanol than catalyst Pt. however, emission rates of formaldehyde and methanol for catalyst Pt were relatively similar to catalyst Pt/Rh.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.7
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• pp.469-473
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• 2003

The effect of photoquenching on infrared image of the EL2 center in semi-insulating(S.I.) GaAs has been studied using near infrared transmission techniques. Particular interest is devoted to as-grown and annealed samples of undoped S.I. GaAs. It is found that the quenching mechanism is different in each sample and also the quenching rate is dependent on the materials and the quenching temperature which is somewhat inconsistent with other existing publications.

• Journal of Korea Port Economic Association
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• v.19 no.2
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• pp.111-139
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• 2003

In this paper, the unbiasedness hypothesis cannot be rejected for JPY. It means that Japanese forward exchange market is efficient. This implies that there would not be an unusual profit from speculation. However, the unbiasedness hypothesis can be rejected for THB, HKD, IDR. It means that Asian forward exchange market is inefficient. This implies that there would be an unusual profit from all available information. This suggests that forward exchange rates cannot be an unbiased estimator of future spot exchange rate. This result explains that the actual pricing for forward rate is not based on the international financial market's pricing mechanism of interest rate parity theory, but rather depends upon that simple market expectations and aspirations.

• International Commerce and Information Review
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• v.9 no.3
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• pp.23-32
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• 2007

The purpose of this study is to estimate and analyse the relationship between efficiency of bank industry and macroeconomic variables. We employ Johansen's multivariate cointegration methodology, since the model must be stationary to avoid the spurious results. The empirical results show that our model is stationary as well as mean-reverting. This paper also applies impulse-response functions to get additional information regarding the responses of the bank spread to the shocks economic variables such as long and short term interest rates differential, banking organ liquidity, business cycle index, and foreigner's net equity investment. The results indicate that while the bank spread respond positively to liquidity and equity investment shocks and then decay very quickly.