• The Journal of Fisheries Business Administration
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• v.23 no.2
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• pp.53-67
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• 1992

It has been recognized, virtually from the time of its inception, that fisheries economics, like other aspects of resource economics, should ideally be cast in capital-theoretic terms. The fish population or biomass can be viewed as a capital stock in that, like conventional or man-made capital, it is capable of yielding a sustainable consumption flow through time. This study is to introduce the optimal control theory which was extended from the theory of calculus of variations into the study of former static theory of fisheries economics started by Gordon (1954). The optimal control theory eliminated the inadequacies of the classical techniques to a large extent. From this point of view, this study, on the base of Schaefer model, summerizes most of major results achieved so far, but does so in a manner such that the links with capital theory are made transparent. This study explores two sets of problems. The first concerns the optimal approach to the equilibrium stock, i.e. the optimal investment policy. The second set of problems arises from the relaxation of the highly restrictive assumption of autonomy (i.e. the assumption that the parameters are independent of time), then concludes the relaxation of linearity assumption together with the complexities caused by that.

• Nuclear Engineering and Technology
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• v.31 no.3
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• pp.303-313
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• 1999

Various interpolation methods have been compared for reconstruction of LMR pin power distributions in hexagonal geometry. Interpolation functions are derived for several combinations of nodal quantities and various sets of basis functions, and tested against fine mesh calculations. The test results indicate that the interpolation functions based on the sixth degree polynomial are quite accurate, yielding maximum interpolation errors in power densities less than 0.5%, and maximum reconstruction errors less than 2% for driver assemblies and less than 4% for blanket assemblies. The main contribution to the total reconstruction error is made tv the nodal solution errors and the comer point flux errors. For the polynomial interpolations, the basis monomial set needs to be selected such that the highest powers of x and y are as close as possible. It is also found that polynomials higher than the seventh degree are not adequate because of the oscillatory behavior.

• Structural Engineering and Mechanics
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• v.51 no.6
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• pp.1017-1036
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• 2014

Steel tubes have an efficient shape with large second moment of inertia relative to their light weight. One of the main problems of these members is their low buckling resistance caused from having thin walls. In this study, steel foams with high strength over weight ratio is used to fill the steel tube to beneficially modify the response of steel tubes. The linear eigenvalue and plastic collapse FE analysis is done on steel foam filled tube under pure compression and three point bending simulation. It is shown that steel foam improves the maximum strength and the ability of energy absorption of the steel tubes significantly. Different configurations with different volume of steel foam and composite behavior is investigated. It is demonstrated that there are some optimum configurations with more efficient behavior. If composite action between steel foam and steel increases, the strength of the element will improve, in a way that, the failure mode change from local buckling to yielding.

• Journal of Forest and Environmental Science
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• v.32 no.1
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• pp.39-54
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• 2016

The present study analyzes the diversity and usage of NTFPs and evaluates their importance in the day to day life of the people of rural Meghalaya. People use 172 NTFPs belonging to 139 plant species mainly for food, medicine and fuelwood and to a lesser extent for construction, handicrafts and ornamental purpose. These 139 plants belonged to 117 genera and 70 families with Rosaceae, Poaceae and Fagaceae families as the dominant NTFP yielding families. Fruits from shrubs and trees are most commonly harvested by people. Collection and availability of NTFPs for use as food are more during the summer season, which is also the period with least availability of job. NTFPs for subsistence use are greater in number than those having commercial value. The most commonly harvested plant parts are fruits and leaves. Roots, rhizomes and whole plants are extracted in lesser quantity which is a positive approach from sustainability point of view. NTFPs and other forest products also form a vital part of the rural household's income generation activities.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.556-561
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• 2005

The steel shows plastic deformation after the yield point exceeds. The plastic deformation due to overloads occurs at the interior support of a continuous bridge. The plastic deformation is concentrated at the interior support and the permanence deformation at the interior support remains after loads apply. Because local yielding causes the positive moment at the interior support, it is called 'auto-moment'. Auto-moment redistributes the elastic moment. Because of redistribution, auto-moment decreases the negative moment at the interior support of a continuous bridge. In this paper, the plastic rotation is evaluated using the moment-rotation curve proposed by Schalling and Beam-line method. Moreover, auto-moment is derived from the experiment curve.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.295-299
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• 1996

Intrinsic Fabry-Perot Optical fiber sensors were embedded to tensile side of the 20cm$\times$20cm$\times$150cm cement concrete structures. The sensors were attached to the reinforcing steels and then, the cement concretes were applied. It took 30 days for curing the specimens. After that, the specimens were tested with 4-point bending method by universal testing machine. Strains were measured and recorded by the strain gauges embedded near optical fiber sensors. Output data of fiber sensor showed good linearity to the strain data from the strain gauges up 2000microstrain. The optical fiber sensors showed good response after yielding of structure while embedded metal film strain gauges did not show any response. We also specimens were broken down. In conclusion, the optical fiber sensors can be used as elements of health monitoring systems for cement concrete infra-structures.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.527-532
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• 1997

Design strength of structural members could be determined by applying a strength reduction factor to nominal strength. At the beginning point of the transition region for the strength reduction factor, P=0.1$\sigma$$_{ck}A_g$, only sectional area and concrete strength are adopted as the variables of P=0.1$\sigma$$_{ck}A_g$. Therefore, P=0.1$\sigma$$_{ck}A_g$ is the empirically adopted which does not consider steel ratio, steel yielding stress, and steel arrangement. So, this research was perpormed the computer program for the analysis of axial force-moment-curvature relationship of reinforced concrete columns by sectional behaviour nonlinear analysis using a concrete compressive stress-strain curve, in order to investigate the ductility of reinforced concrete columns. As a result, ductility indicies of axial force, P=0.1$\sigma$$_{ck}A_g$, represented the lack of consistency of the indicies value for the various sections.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.270-273
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• 2007

In this paper, a SAR-despeck1ing approach of adaptive iteration based a Bayesian model using the lognormal distribution for image intensity and a Gibbs random field (GRF) for image texture is proposed for noise removal of the images that are corrupted by multiplicative speckle noise. When the image intensity is logarithmically transformed, the speckle noise is approximately Gaussian additive noise, and it tends to a normal probability much faster than the intensity distribution. The MRF is incorporated into digital image analysis by viewing pixel types as states of molecules in a lattice-like physical system. The iterative approach based on MRF is very effective for the inner areas of regions in the observed scene, but may result in yielding false reconstruction around the boundaries due to using wrong information of adjacent regions with different characteristics. The proposed method suggests an adaptive approach using variable parameters depending on the location of reconstructed area, that is, how near to the boundary. The proximity of boundary is estimated by the statistics based on edge value, standard deviation, entropy, and the 4th moment of intensity distribution.

• Structural Engineering and Mechanics
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• v.31 no.5
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• pp.567-585
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• 2009

The aim of this study was to investigate the flexural behavior of reinforced concrete beams strengthened with a novel strengthening system. Concrete beams were strengthened with a hybrid retrofit system consisting of high strength steel cords impregnated in an inorganic fireproof matrix (Geopolymer). The strengthened reinforced concrete beams along with non-strengthened control beams were tested monotonically under four point bending loading conditions. Moreover, an analytical model is introduced, that can be used to analyze the flexural performance of the strengthened beams. The experimental results indicate that the failure of the strengthened beams was based on the yielding of the reinforcement in the tension face of the beams, followed by a local slippage of the steel cords. The flexural stiffness of the strengthened beams was significantly improved compared to the stiffness of the non-strengthened beams. In conclusion, the strengthening system can provide an effective alternative to commercially available systems.

• Korean Journal of Plant Resources
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• v.7 no.1
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• pp.23-27
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• 1994

The growing condition and the point at issue were investigated for utilization as a fundamental data of the Boxthorn research in the growing farm household, which was chief producing district of Box-thorn in Chongyang, Chungmam province. The results were summarized as follow'; Lycium fruit wasproduced 445M/. in the 170.4ha. In practical cultivation, major numbers of decapitation were threetimes,, and planting distance was dense planting, and also amount of applied fertilizer was beyondbasic-fertilizer level and number of split application was abundant.Numbers of harvesting were six-ten times, and many labor was requiremented.The issues in cultivation were development of processing technique, supplement of varieties whichhave disease tolerance, superior quality and high yielding, improving of cultivation methods for laborsaving and magnification of demand.