• Environmental and Resource Economics Review
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• v.15 no.4
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• pp.673-692
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• 2006

In order to test for the dynamic optimality condition for the use of nonrenewable resource, it is necessary to estimate the shadow value of the resource in situ. In the previous literatures, a time series for in situ price has been derived either as the difference between marginal revenue and marginal cost or by differentiating with respect to the quantity of ore extracted the restricted cost function in which the quantity of ore is quasi-fixed. However, not only inconsistent estimates are likely to be generated due to the nonmalleability of capital, but the estimate of marginal revenue will be affected by market power. Since firms will likely fail to minimize the cost of the reproducible inputs subject to market prices under realistic circumstances where imperfect factor markets, strikes, or government regulations are present, the shadow in situ values obtained by estimating the restricted cost function can be biased. This paper provides a valid methodology for checking the dynamic optimality condition for a nonrenewable resource by using the input distance function. Our methodology has some advantages over previous ones: only data on quantities of inputs and outputs are required; nor is the maintained hypothesis of cost minimization required; adoption of linear programming enables us to circumvent autocorrelated errors problem caused by use of time series or panel data. The dynamic optimality condition for domestic coal mining does not hold for constant discount rates ranging from 2 to 20 percent over the period 1970~1993. The dynamic optimality condition also does not hold for variable rates ranging from fourth to four times the real interest rate.

• Journal of Korea Technology Innovation Society
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• v.10 no.1
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• pp.47-72
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• 2007

Ideas do not become exhausted, and there are no diminishing returns in the creation of knowledge. Nonetheless, growth ultimately ceases in this simplest model of endogeneous innovation. The reasons are similar to those that are discussed in the context of the neoclassical model of capital accumulation. Even if the resource cost of creating new goods does not rise, the economic return to invention may decline as the number of available products increases. When the rate of return to R&D falls to the level of the discount rate, private agents cease to be willing to defer consumption in order to invest in product development. But, if we treat knowledge capital as a public capital considering of its non-appropriable benefits, economic growth can be sustained in the economy. Romer(1986) has pointed out that growth might be sustainable if the accumulation of knowledge is not subject to long-run diminishing returns. Actually Romer assumed diminishing returns in the production of private knowledge from available resources, but increasing returns in the production of output from labor and total (public and private) knowledge. His condition for the sustainability of long-run growth amounts to an assumption that the diminishing returns in the former activity do not outweigh the increasing returns in the latter. The Johansen(1988) cointegration test method is used for finding long-run equilibrium relationship between R&D input and the product innovation. Test results indicate the existence of cointegrating equation between each pair of regression variables including dependent variable in the knowledge production function. And, the signs of cointegrating vectors are well accord to the prediction of sustainable growth. In the empirical analysis, from all cases of the form for the knowledge production function, we could not reject the null hypothesis that R&D spillover effect is significant($H_{0}:\;{\gamma}=1$). In summary, we showed that considering goodness of fit of regression model, we can see that the empirical evidence is strongly in favor of the character of knowledge as the public knowledge capital. So, we can expect that by product innovation, economic growth can be sustained in the Korean economy.

• International Commerce and Information Review
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• v.16 no.5
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• pp.343-359
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• 2014

This study investigates how cultural differences between countries affect bilateral trade volumes, using Hofstede's cultural index that reflects nations' cultural characteristics. Empirical analyses of the impacts of Hofstede's five cultural characteristics on bilateral trade volumes are conducted either in each separate equation or simultaneously. Bilateral trade data of OECD countries plus China as of year 2010 is used for regression analysis on gravity model. Regression results from individual equation for each cultural index variable show tthe smaller the index gaps of power distances and uncertainty avoidance among countries, the larger bilateral trade volumes. On the contrary, the larger the index gaps of long-term orientation among countries, the larger bilateral trade volumes. If five Hofstede cultural indexes are regressed in a single equation, however, only variables of power distance and long-term orientation are significant. The analysis largely confirms that bilateral trade among countries with similar culture have much potrential to grow. It implies that policy actions for cultural proximity are very important for furthering bilateral trade.

• KDI Journal of Economic Policy
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• v.14 no.4
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• pp.107-121
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• 1992

Moonlighting or second-jobs will increase shirking of the primary job. This paper analyzes the motives for moonlighting so that the means of reducing these motives could be explored. The traditional theory claims that a worker who cannot fully realize his work potential will look to moonlighting. In a two-period model, however, the following motives are more important. The precautionary savings motive : A worker has an incentive to save for fear of losing his job and his income in the second period. The worker could save more by working more during the first period, and this additional motive for working is the precautionary savings motive. The insurance motive : When a worker is unemployed, he cannot expand his moonlighting hours according to his needs since the moonlighting hour is upward rigid. Therefore, a worker has an incentive to secure additional moonlighting hours in the first period so that quick adjustment can be made during the unemployment in the second period. Two policy measures to remove those motives for moonlighting are recommended, for these measures will enhance the productivity in the primary job. First, a firm should guarantee that there will be no layoffs in a downturn in the economy and that the employment level is adjusted to the economic states by work sharing among workers. Second, as unemployment insurance benefits compensate a portion of the income in case of unemployment, it substitutes the motives for moonlighting. A generalization of this argument can be found in Ehrlich and Becker(1972) where self-insurance(moonlighting) and market insurance(in this case, unemployment insurance) serves as substitutes. The two policy measures in the above have a spill-over effect : A decrease of labor supply in the moonlighting market will ease job search, and therefore will help those who have their primary job in the moonlighting sector.

• The Journal of Fisheries Business Administration
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• v.32 no.2
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• pp.91-125
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• 2001

이 논문은 2002년도 부경대학교 수산경영학과 박사학위논문(A Study on Institutional Arrangements for Quota-Based Management : The Case of China's Marine Capture Fisheries)의 일부이다. 이 논문의 기본목적은 취터제에 기초한 중국의 어업관리를 위한 제도적인 틀을 세우고자 하는데 있으며, 이런 목적을 달성하기에 위해 이 논문은 다음과 같이 구성하여 연구를 진행시켰다. 제1장은 연구목적과 문제의 제기에 이어 제2장에서는 중국 해양어업의 개발과 이에 따른 문제점을 분석하였으며, 여기에서 궈터제에 기초한 어업관리정책의 제도적 제안을 함과 동시에, 제3장에서는 중국 해양어업의 현실과 중국 사회의 일반적인 현상을 분석하여 제4장을 통해 쿼터제에 기초한 중국의 어업관리를 위한 제도적 프레임러크를 제안하였다. 마지막으로 본 논문을 요약하고 향후 계속되어야 할 연구과제를 제시하였다. 본 논문의 중요한 연구 결과는 다음과 같다. 현재 중국 수산업의 관리체제는 질적 규제 중심 관리제도, 그리고 정부 주도하의 어업관리 과정으로 특징지을 수 있다. 이러한 명령과 통제 (command-and-control) 방식의 전통적인 중국어업 관리제도로서는 어업인들에게 있어서 자원 보존에 대한 동기와 제도에 대한 수용성을 약화시키며, 정부 규제를 오히려 무시하게 되는 결과를 초래한다. 결과적으로 현형 중국의 어업관리제도는 어업인에게 있어서 자원 보전에 대한 유인을 약화시키고 단기적인 수익을 극대화하도록 유도하는 맹점을 지니므로 인해 더 이상 지속적인 어업성립의 보장을 할 수 없다는 점을 지적할 수 있다. 중국정부는 이러한 어업관리제도의 불완전성을 인식하여 2000년 10월 31일에 1986년 에 제정된 수산업법을 개정하게 되었으며, 새로운 중국의 수산업법은 어업 허가제도와 함께 할당량제에 기초한 어업관리제도를 국가가 운영하는 것으로 특징지을 수 있다. 그러나 아직까지 중국은 할당제에 근거한 어업관리제도를 미실시중에 있으며, 그 내용도 애매모호한 점을 많이 가지고 있다. 또한 중국의 절대적 어획량은 현재 논란의 여지로 남아있고, 거대 어업 인구의 근본적인 요구와 중국 어선의 국제적인 경쟁력, 그리고 유어(遊漁)에 대한 사회적 요구 등도 중국의 수산정책이 채결해야 할 과제이다. 위에서 고찰한 내용을 기초로 하여 우리는 중국의 쿼터제에 기초한 어업관리에 대해 다음과 같은 몇 가지를 제안한다. 중국 연근해어업에 있어서 할당제 모형에 참가하는 어업 참여자들의 유형은 세 가지로 구분할 수 있다. 첫째는 어촌에 거주하면서 생존수단으로 소규모 어업에 종사하는 경우이고, 둘째는 유어어업의 경우이며, 셋째는 상업적 목적으로 어업에 종사하는 집단으로 나눌 수 있다. 이러한 세 집단을 하나의 제도의 틀로 통합하기 위해서는 국가의 총허용어획량(TAC)을 총 어촌 허용어획량(TAIVCs)과 총 허용 유어 어획량(TARCs) 및 총허용 상업적 어획량 (TACCs)의 세부문으로 나눌 것을 제안한다. 그리하여 다시 TAFVCs와 TARCs, 그리고 TACCs는 어촌별 어획량(ITCQs), 개별 유어 회사별 어획량(IRCQs), 그리고 양도 가능한 개별 상업적 어획량(ITCQs)으로 나누어 관리하도록 한다. 이와 같이 중국의 국가 총허용어획량(TAC)을 IFVQs와 IRCQs, 그리고 ITQCQs의 세부문으로 구분하여 할당하고, 여기에 기초하여 어업을 관리하는 것은 중국에 있어서 사회적 형평성과 경제적 효율성과의 상충관계를 고려하여 고안된 것으로, 중국에 있어서 수산업을 통한 경제적 및 사회적 효과를 동시에 기대할 수 있을 것이다.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.2
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• pp.205-213
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• 2018

Development and validation of crop models often require measurements of biomass for the crop of interest. Considerable efforts would be needed to obtain a reasonable amount of biomass data because the destructive sampling of a given crop is usually used. The Kinect sensor, which has a combination of image and depth sensors, can be used for estimating crop biomass without using destructive sampling approach. This approach could provide more data sets for model development and validation. The objective of this study was to examine the applicability of the Kinect sensor for estimation of chinese cabbage fresh weight. The fresh weight of five chinese cabbage was measured and compared with estimates using the Kinect sensor. The estimates were obtained by scanning individual chinese cabbage to create point cloud, removing noise, and building a three dimensional model with a set of free software. It was found that the 3D model created using the Kinect sensor explained about 98.7% of variation in fresh weight of chinese cabbage. Furthermore, the correlation coefficient between estimates and measurements were highly significant, which suggested that the Kinect sensor would be applicable to estimation of fresh weight for chinese cabbage. Our results demonstrated that a depth sensor allows for a non-destructive sampling approach, which enables to collect observation data for crop fresh weight over time. This would help development and validation of a crop model using a large number of reliable data sets, which merits further studies on application of various depth sensors to crop dry weight measurements.

• Korea journal of population studies
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• v.21 no.1
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• pp.162-183
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• 1998

This study examines the sampling bias that may have resulted from the large number of missing observations. Despite well-designed and reliable sampling procedures, the observed sample values in DSFH(Demographic Survey on Changes in Family and Household Structure, Japan) included many missing observations. The head administerd survey method of DSFH resulted in a large number of missing observations regarding characteristics of elderly non-head parents and their children. In addition, the response probability of a particular item in DSFH significantly differs by characteristics of elderly parents and their children. Furthermore, missing observations of many items occurred simultaneously. This complex pattern of missing observations critically limits the ability to produce an unbiased analysis. First, the large number of missing observations is likely to cause a misleading estimate of the standard error. Even worse, the possible dependency of missing observations on their latent values is likely to produce biased estimates of covariates. Two models are employed to solve the possible inference biases. First, EM algorithm is used to infer the missing values based on the knowledge of the association between the observed values and other covariates. Second, a selection model was employed given the suspicion that the probability of missing observations of proximity depends on its unobserved outcome.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.2
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• pp.98-105
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• 2013

The purpose of this study was to investigate the mesiodistal widths at the cervical level of primary second molars in Korean children, and to compare them with commercial rubber dam clamps commonly used in pediatric dentistry. Dental casts of 115 primary and mixed dentition children were studied. Cervical mesiodistal width (C-MD) was measured at the clinical cervical level of each primary second molar from buccal and lingual sides using a digital caliper (Absolute, Mitutoyo, Kawasaki, Japan). The data were compared with mesiodistal widths of rubber dam clamps #203/204, #10/11, and #205 (Dentech, Japan). C-MDs of primary mandibular second molars were larger than those of primary maxillary second molars, and C-MDs at buccal sides were larger than those of lingual sides. All C-MDs showed statistically significant discrepancies to corresponding widths on clamps (p < 0.05). However the amount of discrepancy was mild in maxillary teeth, while up to 1 mm of discrepancy was shown in mandibular teeth. In conclusion, C-MDs measured in this study imply a relatively fair fit of #10/#11 or #203/#204 clamps on primary maxillary second molars, while suggesting our need for a better clamp with proper size for primary mandibular second molars.

• The Korean Journal of Financial Management
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• v.8 no.2
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• pp.209-255
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• 1991

This paper develops a simple model to explain the reasons why foreign acquirers pay significantly higher premiums for U.S. target firms than do U.S. buyers. We also provide empirical work on the valuation effect of foreign takeovers and the determinants of the wealth gains of U.S. target shareholders involved in foreign takeovers. The results indicate that target wealth gains are significantly higher in foreign takeovers than in domestic takeovers, after controlling for the wealth effects of payment method, acquisition type, tax status, size and time period of bids. This confirms the valuation effect of foreign takeovers. Furthermore, the results of cross-sectional regression analysis show that the variation in U.S. target wealth gains is explained by extra tax benefits stemming from double tax deductions for acquisition-related interest expenses incurred by foreign acquirers. These findings imply that differential taxation across tax jurisdictions is the main source of the valuation effect of foreign takeovers. In addition, we find that there exists a valuation effect of the nationality of the foreign acquirers. Japanese companies pay significantly higher premiums than do non-Japanese acquirers. The finding also indicates that competition among bidders increases the abnormal returns to U.S. target shareholders in foreign takeovers.

• Nuclear Engineering and Technology
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• v.27 no.6
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• pp.811-824
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• 1995

The CANDU element bowing is attributed to actions of both the thermally induced bending moments and the bending moment due to hydraulic drag and mechanical loads, where the bowing is defined as the lateral deflection of an element from the axial centerline. This paper consider only the thermally-induced bending moments which are generated both within the sheath and the fuel and sheath by an asymmetric temperature distribution with respect to the axis of an element The generalized and explicit analytical formula for the thermally-induced bending is presented in con-sideration of 1) bending of an empty tube treated by neglecting the fuel/sheath mechanical interaction and 2) fuel/sheath interaction due to the pellet and sheath temperature variations, where in each case the temperature asymmetries in sheath are modelled to be caused by the combined effects of (i) non-uniform coolant temperature due to imperfect coolant mixing, (ii) variable sheath/coolant heat transfer coefficient, (iii) asymmetric heat generation due to neutron flux gradients across an element and so as to inclusively cover the uniform temperature distributions within the fuel and sheath with respect to the axial centerline. As the results of the sensitivity calculations of the element bowing with the variations of the parameters in the formula, it is found that the element bowing is greatly affected relatively with the variations or changes of element length, sheath inside diameter, average coolant temperature and its variation factor, pellet/sheath mechanical interaction factor, neutron flux depression factor, pellet thermal expansion coefficient, pellet/sheath heat transfer coefficient in comparison with those of other parameters such as sheath thickness, film heat transfer coefficient, sheath thermal expansion coefficient and sheath and pellet thermal conductivities.