• 한국산림과학회지
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• 제85권3호
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• pp.360-371
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• 1996

산림휴양자원의 효과적인 관리를 위해서는 휴양지의 현재 관리상태를 평가하고 이를 토대로 지속적으로 관리할 수 있는 객관적이고 수량화된 평가기준의 설정이 필요하다. 규범적 접근방법은 이러한 평가기준을 설정할 수 있는 하나의 대안으로써, 학자들 사이에 이에 대한 관심이 증대되고 있으며 그 유용성 또한 강조되어 왔다. 본 연구는 1993년도에 지리산 국립공원내의 두 야영장(뱀사골 야영장과 제2야영장)을 이용하는 야영객들을 대상으로 실시한 현지설문조사를 토대로 수행되었다. 규범적 접근방법을 이용하여 8개 지표항목에 대한 평가기준을 설정하고 이를 토대로 현재 야영장 관리상태를 평가하였다. 뱀사골 야영장과 제2야영장에서 모두 소음시간과 쓰레기 버리는 행위에 대한 현재 상태가 본 연구에서 설정된 평가기준보다 좋지 않은 것으로 나타났으며, 무례한 행위, 텐트수, 야영객수, 급수시설을 이용하기 위해 기다리는 시간은 뱀사골 야영장에서만 평가기준보다 불량한 것으로 나타났다. 텐트사이의 거리와 화장실을 이용하기 위해 기다라는 시간에 대한 현재 상태는 두 야영장에서 모두 평가기준보다 양호했다. 본 연구는 규범적 접근방법이 평가기준설정을 위해 실질적으로 어떻게 이용될 수 있는가를 소개하고, 분석결과를 토대로 휴양자원 관리개선방안을 제시하였다.

• Steel and Composite Structures
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• 제49권5호
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• pp.547-570
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• 2023

In the present work, a comparative study has been carried out between power, exponential, and sigmoidal sandwich FGM plates for free vibration conditions under hygro-thermal conditions. Rules of mixture is used to determine effective material properties across the thickness for power-law and sigmoid sandwich FGM plates. Exponential law is used to plot effective material properties for exponentially graded sandwich FGM plates. Temperature and moisture dependent material properties were used during the analysis. Free vibration analysis is carried out using recently proposed finite element based HOZT. Present formulation satisfies interlayer transverse stress continuity conditions at interfaces and transverse shear stress-free conditions at the plate's top and bottom surfaces. The present model is free from any penalty or post-processing requirements. Several new results are reported in the present work, especially for unsymmetric sandwich FGM plates and exponential and sigmoidal sandwich FGM plates.

• Advances in aircraft and spacecraft science
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• 제7권1호
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• pp.19-40
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• 2020

In the present study, a fifth-order shear and normal deformation theory using a polynomial function in the displacement field is developed and employed for the static analysis of laminated composite and sandwich simply supported spherical shells subjected to sinusoidal load. The significant feature of the present theory is that it considers the effect of transverse normal strain in the displacement field which is eliminated in classical, first-order and many higher-order shell theories, while predicting the bending behavior of the shell. The present theory satisfies the zero transverse shear stress conditions at the top and bottom surfaces of the shell. The governing equations and boundary conditions are derived using the principle of virtual work. To solve the governing equations, the Navier solution procedure is employed. The obtained results are compared with Reddy's and Mindlin's theory for the validation of the present theory.

• 대한가정학회지
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• 제28권4호
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• pp.51-63
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• 1990

The purpose of this study is to find out the present conditions and the residents' satisfaction with the storage spaed and furniture in apartment smaller than 40 pyoun(132㎡). The following were investigated; 1. the rate of residents using beds and their future desire for using beds. 2. the rate of households that have built-in furniture, and residents' desire for having them. 3. types of storage furniture more needed. 4. residents' level of satisfactio with the present storage space. 5. the depths of wardrobes and the heights of racks inside wardrobes. 6. storing conditions of articles seasonal or seldom used.

• Advances in aircraft and spacecraft science
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• 제6권5호
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• pp.409-426
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• 2019

The aim of the present work is to study the nonlinear behavior of the laminated composite plates under transverse sinusoidal loading using a new inverse trigonometric shear deformation theory, where geometric nonlinearity in the Von-Karman sense is taken into account. In the present theory, in-plane displacements use an inverse trigonometric shape function to account the effect of transverse shear deformation. The theory satisfies the traction free boundary conditions and violates the need of shear correction factor. The governing equations of equilibrium and boundary conditions associated with present theory are obtained by using the principle of minimum potential energy. These governing equations are solved by eight nodded serendipity element having five degree of freedom per node. A square laminated composite plate is considered for the geometrically linear and nonlinear formulation. The numerical results are obtained for central deflections, in-plane stresses and transverse shear stresses. Finite element Codes are developed using MATLAB. The present results are compared with previously published results. It is concluded that the geometrically linear and nonlinear response of laminated composite plates predicted by using the present inverse trigonometric shape function is in excellent agreement with previously published results.

• 한국환경과학회지
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• 제8권5호
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• pp.575-586
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• 1999

From the environmental aspects, primary productivity of phytoplankton plays the most improtant role in enhancement of marine culture oyster production. This study may be divided into two branches; one is estimation of maximum oyster meat production per unit facility(Carrying Capacity) under the present enviromental conditions in Kamak Bay, the other is improvement of carrying from increase of primary productivity by changing the environmental conditions that cause not ot form an unfavorable environment such as the formation of oxygen deficient water mass using the eco-hydrodynamic model. By simulation of three-dimensional hydrdynamic model and ecosystem model, the comparison between observed and computed data showed good agreement. The results of sensitivity analysis showed that phytoplankton maximum growth rate was the most important parameter for phytoplankton and dissolved oxygen. The estimation of mean primary productivity of Wonpo, Kamak, Pyongsa, and Kunnae culture grounds in Kamak Bay during culturing period were 3.73gC/$m^2$/d, 2.12gC/$m^2$/d, 1.98gC/$m^2$/d, and 1.26gC/$m^2$/d, respectively. Under condition not ot form the oxygen deficient water mass, four times increasing of pollutants loading as much as the present loading from river increased mean primary productivity of whole culture grounds to 4.02gC/$m^2$/d. Sediment N, P fluxes that allowed for 35% increasing from the present conditions increased mean primary productivity of whole culture grounds to 3.65gC/$m^2$/d. Finally, ten times increasing of boundary loadings from the present conditions increased mean primary productivity of whole culture grounds to 3.95gC/$m^2$/d. The maximum oyster meat production per year and that of unit facility in actual oyster culture grounds under the present conditions were 6,929ton and 0.93ton, respectively. This 0.93ton/unit facility is considered to be the carrying capacity in study area, and if the primary productivity is increased by changing the environmental conditions, oyster production can be increased.

• 대한조선학회논문집
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• 제58권3호
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• pp.158-166
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• 2021

In this paper, a numerical analysis technique using a body force model is investigated to estimate the available net thrust of multi-pod-driven ice-breaking vessels under bollard pull and overload conditions. To employ the body force model in present flow simulations, drag and thrust components acting on the pod unit are calculated by using Propeller Open Water (POW) test data. The available net thrusts according to the direction of operation are evaluated in both bollard pull and overload conditions under deep water. The simulation results are compared with the model test data. The available net thrusts, calculated by the present analysis for ahead operating modes at 3~6 knots which are typical speeds of the target vessel in arctic field, are agreed well with the model test results. It is also found that the present result for astern operating mode appears approximately 6 % larger than the model test result. In addition, the available net thrusts are calculated under the both operating conditions accompanied by shallow water effects, and the main cause of the difference is studied. Based on the result of the present study, it is confirmed that the body force model can be applied to the performance evaluation of multi-pod propulsion system and the main engine selection in early design stage of the vessel.

• Bulletin of the Korean Chemical Society
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• 제20권6호
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• pp.643-647
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• 1999

Hydropalladium carboxylates, formed from π-allylpalladium chloride dimer plus carboxylic acids, have been shown to catalyze cyclization of structurally diverse enediynes to form the corresponding six- or five-membered rings depending upon the reaction conditions. Some enediynes having an Oxygen linker in an appropriate position under the similar condition yielded the corresponding cyclopropanation products in highly stereoselective manner. A study using deuterated formic acid has proven that the alkylpalladium intermediates formed in our conditions were reduced by the pendant formate ligand. The dienediyne 10 yielded only the tricyclic product 12 in 67% yield, although it was expected to frrm the cyclic product 11. All these cyclizations seemed to occur via the corresponding alkylpalladium intermediates I. which could proceed to the corresponding cyclic products depending on the reaction conditions and the substrates. The study using ceuterated formic acid could provide an important information to understand the present cyclization mechanism. Overall the present study could play an important role in developing new synthetic methodologies for constructing complex polycyclic compounds.

• Advances in materials Research
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• 제12권1호
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• pp.43-65
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• 2023

Free vibration analysis of power law and sigmoidal sandwich plates made up of functionally graded materials (FGMs) has been carried out using finite element based higher-order zigzag theory. The present model satisfies all-important conditions such as transverse shear stress-free conditions at the plate's top and bottom surface along with continuity condition for transverse stresses at the interface. A Nine-noded C0 finite element having eleven degrees of freedom per node is used during the study. The present model is free from the requirement of any penalty function or post-processing technique and hence is computationally efficient. The present model's effectiveness is demonstrated by comparing the present results with available results in the literature. Several new results have been proposed in the present work, which will serve as a benchmark for future works. It has been observed that the material variation law, power-law exponent, skew angle, and boundary condition of the plate widely determines the free vibration behavior of sandwich functionally graded (FG) plate.

• ETRI Journal
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• 제30권6호
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• pp.865-867
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• 2008

A conventional environment adaptation for robust speech recognition is usually conducted using transform-based techniques. Here, we present a discriminative adaptation strategy based on a multi-condition-trained model, and propose a new method to provide universal application to a new environment using the environment's specific conditions. Experimental results show that a speech recognition system adapted using the proposed method works successfully for other conditions as well as for those of the new environment.