自然資源의 槪念과 農業資源經濟學의 硏究對象에 관한 考察

李承來 釜山水産大學校 1982 論文集 Vol.29 No.-

When human behavior is presumed as rational activity, all the objects of human activity can be resources in a broad sense, which of course include natural, cultural, and human resources, but they indicate only natural resources in a narrow sense. Agricultural resources thus mean nothing but agriculture's natural resources which are divided into meteorological resources as renewable resources and biological resources such as land and water. Resources as the object of Resource Economics imply only natural resources, especially those of scarcity, Agricultural Resource Economics manages agriculture's natural resources to the exclusion of meteorological resources because it isn't regarded as economic resources. In the end, Agricultural Resource Economics restricts its area within water and land resources. If land in a broad sense may include water resources, Agricultural Resource Economics can be a science dealing mainly with land resources. And when land resources is economically analyzed as its object, there are many limitative factors around physical, biological and institutional spheres. As existing Economics so far has concentrated on economic use under the institutional restrictive condition, It cannot be denied that reaction of natural resources has caused serious issues on human activity, and that one of the main controversial issues in agricultural natural resources is natural conservation. More attention must be paid to physical and biological aspects than to institutional aspects. In the one hand, the ultimate aim of Agricultural Resource Economics is to promote national welfare, for which Agricultural Economics as applied economics deals with production, macketing, destribution, consumption of agricultural products, Agricultural Resource Economics can be a branch of Agricultural Economics on the ground that the former deals with only agricultural production out of various fields. Agricultural Production Economics also manage agricultural production as its field, but Production Economics tries to maximize profit through the optimum combination under the premise of given resources from private sector. On the other hand, Agricultural Resource Economics, taking its stand on public sector, deals mainly with the way in which productive factors can be stabily supplied without a stop. Though existing Land Economics tends to place real estated as well as agricultural land in the category, Agricultural Resource Economics deals mainly with farm land essential to agricultural producing. So Agricultural Resource Economics can be called a branch of Land Economics.

자원경제학의 생성과정에 관한 고찰

이승래 釜山水産大學校 1984 論文集 Vol.32 No.-

일반 등방경화규칙에 의거한 점토의 비등방 탄소성 구성모델

이승래,오세붕 한국지반공학회 1994 지반 : 한국지반공학회지 Vol.10 No.3

역재하시에 나타나는 흙의 비등방거동을 모델하기 위하여, 본 연구에서는 일반 등방경화규칙에 근거한 비등방 경화이론을 개발하였다. 일반 등방규칙은 등방경화의 기준이 되는 중심응력텐서가 임의의 응력상태에서 존재할 수 있도록 허용하므로, 역재하과정에서 발생하는 소성변형을 예측할 수가 있다. 제안된 구성모델은 단순한 경화함수만을 이용하여 수식화되었고, 일반등방경 화규칙에 적용된 개념을 기존의 비등방경화규칙과 비교하여 서술하였다. 검증을 위하여, 배수 및 비배수조건, 과압밀상태, Ko 압밀등의 초기조건이 상이한 점토에 대하여 관측된 삼축압축시료의 거동을 예측하였다. To model the anisotropic behavior of soils in the case of reverse loading, an anisotropic hardening description is proposed on the basis of generalized isotropic hardening(GIH) rule. There is a core of the GIH rule in the allowance of the concept that the center of homology of isotropic hardening can be any proper stress states inside a yield surface. The plastic deformations could be represented for the condition of reverse loading, and an explicit constitutive relationship was formulated by utilizing a simple hardening function. The proposed hardening description has been compared with other anisotropic hardening models. For verification three sets of triaxial test results have been predicted for the drained and undrained behavior of overconsolidated clays and Ko consolidated clays.

해운기업의 해외직접투자가 재무성과에 미치는 영향 분석

이승래,이재민 한국무역통상학회 2017 무역통상학회지 Vol.17 No.4

This paper empirically analyzes the effects of foreign direct investment (FDI) on financial performance of marine transportation companies between 2005 and 2013. By using firm-level data of 407 companies in marine transportation sector during the sample period, we find that FDI companies experience severe financial difficulties with respect to companies that do not engage in FDI. Considering that marine transportation company’s FDI decision is largely affected by the foreign corporate tax rates, we estimate two-stage least squares model to find that an increase in foreign investment that is made to the foreign subsidiaries from exploiting low foreign corporate tax rates significantly worsens financial performance of parent firms over time. These results provide evidence that recent collapse of Korea’s top marine transportation companies is partially associated with prior FDI increase.

흙막이 구조물(III)

이승래 한국지반공학회 1992 지반 : 한국지반공학회지 Vol.8 No.2

자연자원의 경제분석에 관한 고찰

이승래 釜山水産大學校 1987 論文集 Vol.38 No.-

미약한 과압밀상태의 점토지반에 대한 구성모델

이승래,오세붕 한국지반공학회 1992 지반 : 한국지반공학회지 Vol.8 No.4

연약한 점토지반에서는, 정규압밀상태와 더불어 미약한 과압밀상태에서의 구성관계가 실제 지반구조물의 거동을 해석하는 데 중요한 역할을 한다. 미약한 과압밀상태의 거동에 실용적으로 적용될 수 있는 구성모델은 비교적 간편한 계수만을 사용하여 실제의 다양한 거동을 정확하게 예측할 수 있도록 개발되어야 한다. 이러한 연유로 본 연구에서는 등가응력 (자)으로규준화하였을 때 나타나는 지반의 비 배수거동을 재현하여 미약한 과압밀상태에 적용할 수 있는 구성모델을 제안하였다. 제안된 모델은 단지 정규압밀상태의 거동으로 도출할 수 있는 모델계수만을 사용하여 초기항복면내부에서 발생하는 항복현상을 표현할 수 있다. 뿐만아니라 제안된 모델은 과압밀상태, 2차압밀, 응력이완등의 영향에 따른 실제의 거동을 기존의 모델들에 비하여 더욱 간편하고 정확하게 예측할 수 있다. Constitutive relations for lightly overconsolidated state of clayey soils. as well as normally consolidated state of those, play an important role in the analyses of geotechnical structures in clay deposits. For the practical point of view, a constitutive model applicable to lightly overconsolidated soils should be developed to easily evaluate the model parameters, and to precisely predict the various behavior of OC soils. For that purpose, a constitutive model for the lightly overconsolidated soil behavior has been proposed to rep- resent the undrained behavior which can be normalized using equivalent pressure, p. , Yielding within the initial yield surface is modeled exclusively using the given normally consolidated model parameters only. Furthermore, the proposed model can be applied to consider the effects of overconsolidation, secondary consolidation, and stress relaxation. The measured behavior in undrained triaxial tests has been Predicted easily and precisely in comparison with other models.

자원경제학과 후생경제학과의 관계 고찰

이승래 釜山水産大學校 1985 論文集 Vol.35 No.-

말뚝 진동 기초의 설계

이승래 한국전산구조공학회 1993 전산구조공학 Vol.6 No.1

본문에서는 기계진동에 대한 말뚝기초의 설계에 대하여 간략하게 기술하였으며 본문에 기술된 방법들은 여러 가정들을 통하여 얻어진 것으로 경우에 따라서는 실제 거동과는 매우 상이한 거동을 예측할 수 있으므로 실제 설계에 이용되는 경우, 특히 주어진 지반의 물성치 선택 등에 주의를 요할 필요가 있다.

화강풍화토 지반의 불포화 특성을 고려한 최적화기법에 의한 사면안정해석 방법

이승래,이성진,변위용,장범수 한국지반공학회 2001 한국지반공학회논문집 Vol.17 No.6

대부분의 토사사면은 불포화상태로서, 이 경우 기존의 모관흡수력을 무시한 해석에 비해 보다 합리적인 결과를 얻을 수 있도록 대상 사면지반의 불포화 특성을 고려할 필요가 있다. 따라서 본 연구에서는 지반의 불포화 특성을 고려할 수 있도록 한계평형법에 의한 사면안정해석 프로그램을 보완하여 작성하였으며 임계단면 탐색을 위하여 최적화 기법을 적용하였다. 그리고 이와 같은 해석을 위한 불포화 설계변수를 얻기 위해 국내의 대표적 지반 재료인 화강풍화토에 대해 실험을 수행하였다. 실험자료 분석결과 불포화 강도특성을 안정해석에 적용하기 위해 모관흡수력에 따른 겉보기 점탁력 변화를 비선형성을 고려하여 수식화하였다. 또한 부피변화를 측정함으로써 함수특성곡선을 보다 정확하게 얻고자 하였다. 본 연구 결과를 통해 강우에 의한 침투로 야기되는 사면내부의 모관흡수력의 변화와 그에 따른 투수특성 및 강도특성변화를 고려함으로써 강우강도와 지속시간에 따른 안전율 변화를 보다 적절히 판단할 수 있었다. Since most of soil slopes are in an unsaturated state, it is necessary to consider the unsaturated characteristics of soil slopes, in order to obtain more reasonable results. Therefore in this study we supplemented a slope stability analysis program to consider them, based on the concept of limit equilibrium. We also applied an optimization technique to search for a failure surface. Besides, we carried out experiments to obtain the unsaturated soil properties required in the analysis with weathered granite soils. We formulated a nonlinear apparent cohesion relationship with the matrix suction to be able to apply the unsaturated shear strength characteristics to the stability analysis. In addition, we intended to obtain more accurate soil water characteristic curves(SWCC) by measuring the change in volume of the specimen in the SWCC tests. As a result, we could appropriately assess the change of the safety factor according to the rainfall intensity and duration, by considering the variation of suction, permeability, and shear strength caused by the infiltration of rainfall into slopes.