• Journal of the Society of Naval Architects of Korea
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• v.49 no.1
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• pp.99-108
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• 2012

In this paper, fatigue tests are conducted for the specimens with longitudinal and transverse attachment under variable amplitude axial loading based on storm model. Considered loadings include repeated single storm, 6 or 8 storms randomly, and storms including calm sea condition while the mean stress and the maximum stress of loadings are changed. The effect of three variables are investigated; root mean square(RMS) value of stress amplitude, mean stress shift and maximum stress, which can characterize storm loading on fatigue life. In addition, experiments including calm sea loading are also carried out to investigate the effect of calm sea state. Test results are evaluated and compared with DNV-CN2005 and Matsuoka's method for the estimation of crack initiation and propagation life. To verify the validity of the criteria, the measured crack initiation lifes are compared with the specific crack length 15mm, which are calculated with beach marks.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.1
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• pp.1-11
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• 2013

In this study, in order to increase the span length, the temporary bridge which the center part of span is strengthened by small H-beam and the end part of span is strengthened by steel plate is designed and constructed. Real behavior of proposed temporary bridge is analyzed by field loading test. Analyzed shear buckling strengths and nonlinear behavior of suggested temporary bridge are compared with the those of general temporary bridge. From the field loading test results, it is analyzed that real static behavior of suggested temporary bridge is agree with the analyzed behavior which is considered in design process. Under the proposed design condition, it is investigated that the shear buckling strength of suggested temporary bridge is about 40% higher than that of general temporary bridge, and the ultimate strength of suggested temporary bridge is about higher than that of general temporary bridge. From the study results, it is concluded that the proposed temporary bridge can be applied by the needs of field condition.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.3
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• pp.10-17
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• 2016

Control Chart is a graph which dots the characteristic values of a process. It is the tool of statistical technique to keep a process in controlled condition. It is also used for investigating the state of a process. Therefore many companies have used Control Chart as the tool of statistical process control (SPC). Products from a production process represent accidental dispersion values around a certain reference value. Fluctuations cause of quality dispersion is classified as a chance cause and a assignable cause. Chance cause refers unmanageable practical cause such as operator proficiency differences, differences in work environment, etc. Assignable cause refers manageable cause which is possible to take actions to remove such as operator inattention, error of production equipment, etc. Traditionally ${\bar{x}}-R$ control chart or ${\bar{x}}-s$ control chart is used to find and remove the error cause. Traditional control chart is to determine whether the measured data are in control or not, and lets us to take action. On the other hand, RNELCC (Reflected Normal Expected Loss Control Chart) is a control chart which, even in controlled state, indicates the information of economic loss if a product is in inconsistent state with process target value. However, contaminated process can cause control line sensitive and cause problems with the detection capabilities of chart. Many studies on robust estimation using trimmed parameters have been conducted. We suggest robust RNELCC which used the idea of trimmed parameters with RNEL control chart. And we demonstrate effectiveness of new control chart by comparing with ARL value among traditional control chart, RNELCC and robust RNELCC.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.4
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• pp.121-133
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• 2015

The TANK model has been widely used in rainfall-runoff modeling due to its simplicity of concept and computation while achieving forecast accuracy. A major barrier to the model application is to determine parameter values for ungauged watersheds, leading to the need of a method for the parameter estimation. The objective of this study was to develop regression equations for estimating the 3th TANK model parameters considering their variations for the ungauged watersheds. Thirty watersheds of dam sites and stream stations were selected for this study. A genetic algorithm was used to optimize TANK model parameters. Watershed characteristics used in this study include land use percent, watershed area, watershed length, and watershed average slope. Generalized equations were derived by correlating to the optimized parameters and the watershed characteristics. The results showed that the TANK model, with the parameters determined by the developed regression equations, performed reasonably with 0.60 to 0.85 of Nash-Sutcliffe efficiency for daily runoff. The developed regression equations for the TANK model can be applied for the runoff simulation particularly for the ungauged watersheds, which is common for upstream of agricultural reservoirs in Korea.

• Journal of the Korean Society for Marine Environment & Energy
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• v.20 no.2
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• pp.63-75
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• 2017

In offshore environment, an accurate estimation of a wave-structure interaction has been an important issue for safe and cost effective design of fixed and floating offshore structures exposed to a harsh environment. In this study, a wave-structure interaction around a circular column was investigated with regular waves. To simulate 3D two-phase flow, open source computational fluid dynamics libraries, called OpenFOAM, were used. Wave generation and absorption in the wave tank were activated by the relaxation method, which implemented in a source term. To validate the numerical methods, generated Stokes 2nd-order wave profiles were compared with the analytic solution with deep water condition. From the validation test, grid longitudinal and vertical sizes for wave length and amplitude were selected. The simulated wave run-up and wave loads on the circular column were studied and compared with existing experimental data.

• International Journal of Industrial Entomology and Biomaterials
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• v.30 no.1
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• pp.6-16
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• 2015

This study established the genetic characterisation of 10 microsporidian isolates infecting non-mulberry silkworms (Antheraea assamensis and Samia cynthia ricini) collected from biogeographical forest locations in the State of Assam, India, using PCR-based markers assays: inter simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD). A Nosema type species (NIK-1s_mys) was used as control for comparison. The shape of mature microsporidian spores were observed oval to elongated, measuring 3.80 to $4.90{\mu}m$ in length and 2.60 to $3.05{\mu}m$ in width. Fourteen ISSR primers generated reproducible profiles and yielded 178 fragments, of which 175 were polymorphic (98%), while 16 RAPD primers generated reproducible profiles with 198 amplified fragments displaying 95% of polymorphism. Estimation of genetic distance coefficients based on dice coefficients method and clustering with un-weighted pair group method using arithmetic average (UPGMA) analysis was done to unravel the genetic diversity of microsporidians infecting Indian muga and eri silkworm. The similarity coefficients varied from 0.385 to 0.941 in ISSR and 0.083 to 0.938 in RAPD data. UPGMA analysis generated dendrograms with two microsporidian groups, which appear to be different from each other. Based on Euclidean distance matrix method, 2-dimensional distribution also revealed considerable variability among different identified microsporidians. Clustering of these microsporidian isolates was in accordance with their host and biogeographic origin. Both techniques represent a useful and efficient tool for taxonomical grouping as well as for phylogenetic classification of different microsporidians in general and genotyping of these pathogens in particular.

• Journal of the Korean Society for Nondestructive Testing
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• v.13 no.2
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• pp.31-39
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• 1993

It has not been performed to inspect the underclad cracking of nuclear pressure vessel in Korea since there is no code requirements for inspection. However, underclad cracks in nuclear pressure vessels have been reported since the early 1970s. The aim of this experiment is to find the suitable ultrasonic inspection techniques for underclad cracking. The various transducers, for example $70_{\backprime}$ refracted longitudinal wave, 50/70 multibeam, SLIC-40, SLIC-50, are used in this investigation. Experiments on prescreening blocks and a demonstration block under the same condition as in the nuclear power pressure vessels show that the $70_{\backprime}$ refracted longitudinal wave method is the best one for the length evaluation and also gives a good signal pattern for detection of the crack, while the 50/70 multibeam transducer is more effective for the detection of underclad cracking. On the other hand, the SLIC-50 transducer using M-SPOT(Satellite Pulse Observation Technique) and M-PET (Peak-Echo Technique) methods is the most effective one for the depth of underclad crack estimation.

• Korean Journal of Medicinal Crop Science
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• v.14 no.3
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• pp.183-187
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• 2006

This study carried out to analize quality in the evaluation based on the grades such as raw ginseng and red ginseng between Korean (Panax ginseng C. A. Meyer) and American ginseng (Panax quinquefolium L). American ginseng was small in root length, root diameter and root weight and emergence many secondary root from rhizome and main root. Therefore body form was bad compared with Korean ginseng. As for yield of dry, Korean ginseng was 30.4 % and American ginseng was 33.8% but as for yield, Korean ginseng was 80.4% and American ginseng was 72.2%. There were as many Korean ginseng in raw ginseng first grade by about twice compared with American ginseng. However there were many American ginseng in second grade. On the other hand, Korean ginseng producted high Chunsam compared with American ginseng. The cause of decreasing quality was inside cavity and inside white in Korean and American ginseng. Especially, the inside white occurrence about 3 times compared with inside cavity in American ginseng. In the case of distribution of weight size, Korean ginseng was much above 20Ji but American ginseng was much under 20Ji.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.4 no.1
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• pp.11-19
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• 2008

Groundwater flow in confined aquifer and heat transport in underground geologic media are using same governing equation(line source) like well fuction. Therefore the conventional slope method using only later data obtained from in-situ thermal response test to determine the thermal conductivity of vertical geothermal heat exchanger(GHEX) is basically identical with one of Theis straight line method of aquifer test under artesian condition. In case that the pumping rate(Q, $m^3$/d) and drawdown(s,m) which are used for input data of existing hydrogeologic computer programs for aquifer test are replaced and converted to supplying heat energy per unit length of bore hole(Q/L,w/m or Kcal/h.m) and temperatures (T,$^{\circ}C$)measured at in and out-let of GHEX as in put data respectively, thermal conductivity around geothermal heat exchanger can be easily estimated without any special modification of the existing hydrogeologic computer program. Two numbers of time series temperature variation data obtained from in situ geothermal response test are analized using Theismethods(standard curve and straight line method) by using existing aquifer test program and conventional Slope method proposed by ASHRAE. The results show that thermal conductivity values estimated by two straight methods are identical and the difference of estimated values between standard curve methods and Slope method are also within acceptable ranges. In general,the thermal conductivity estimated from Theis straight linemethod gives more accurate value than the one of Slope method due to that Slope method uses only visual matching otherwise Theis method uses automatic curve matching estimation with reducing RSS.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5A
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• pp.289-297
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• 2012

This study proposes an experimental formula that can estimate the applied tensile stress of a bonded PSC by measuring a longitudinal stress wave velocity of tendon. To develop practical formula, the various bonded PSC specimens are constructed with different levels of prestresses. For all the bonded PSC specimens, the longitudinal impact-echo tests are repeated with various experimental conditions. Considering a few influence factors such as temperature, length and the number of strands, the application of the law of similarity results in a nondemensional experimental formula that could estimate existing tensile stress on tendon by measuring its longitudinal stress wave velocity. Next, a feasibility study of proposed approach has been conducted for a real reactor building containment. The estimated stress levels of two vertical tendons embedded in the nuclear plant are close to their design values.