• 대한조선학회논문집
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• 제61권1호
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• pp.44-50
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• 2024

In order to reasonably predict damage extents of naval ships under in-compartment explosion (INCEX) loads, two conditions should be fulfilled in terms of accurate INCEX load generation and fracture estimation. This paper seeks to predict damage extents of various naval ships by applying the CONWEP model to generate INCEX loads, combined with the Hosford-Coulomb (HC) and localized necking (LN) fracture model. This study selected a naval ship with a 2,000-ton displacement, using associated specifications collected from references. The CONWEP model that is embedded in a commercial finite element analysis software ABAQUS/Explicit was used for INCEX load generation. The combined HC-LN model was used to simulate fracture initiation and propagation. The permanent failures with some structural fractures occurred where at the locations closest to the explosion source points in case of the near field explosions, while, some significant fractures were observed in way of the interfaces between bulkheads and curtain plates under far field explosion. A large thickness difference would lead to those interface failures. It is expected that the findings of this study enhances the vulnerability design of naval ships, enabling more accurate predictions of damage extents under INCEX loads.

• 대한산업공학회지
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• 제19권1호
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• pp.61-71
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• 1993

We focus on a way of combining the Monte Calro methods of antithetic variates and control variates to reduce the variance of the estimator of the mean response in a simulation experiment. Combined Method applies antithetic variates (partially) for driving approiate stochastic model components to reduce the vaiance of estimator and utilizes the correlations between the response and control variates. We obtain the variance of the estimator for the response analytically and compare Combined Method with control variates method. We explore the efficiency of this method in reducing the variance of the estimator through the port operations model. Combined Method shows a better performance in reducing the variance of estimator than methods of antithetic variates and control variates in the range from 6% to 8%. The marginal efficiency gain of this method is modest for the example considered. When the effective set of control variates is small, the marginal efficiency gain may increase. Though these results are from the limited experiments, Combined Method could profitably be applied to large-scale simulation models.

• 한국철도학회논문집
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• 제3권1호
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• pp.34-41
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• 2000

The analysis of static and dynamic characteristics of reinforced roadbed materials was performed through model and laboratory tests. The strength characteristic of reinforced roadbed materials such as HMS-25 and soil were investigated through the unconfined axial compression test, the model soil box test and the combined resonant column and torsional shear test. The unconfined axial compression strength of HMS-25 shows a steady increasement in strength due to the chemical hardening reaction between HMS-25 and water. The result of model soil box test reveals that railroad roadbed of HMS-25 is better than that of soil in several aspects, such as, bearing capacity and settlement. The combined resonant column and torsional shear test result indicates that shear modulus of HMS-25 and soil increase with the power of 0.5 to the confining pressure and linear relationship to normalized shear modulus and damping ratio.

• 한국정보시스템학회지:정보시스템연구
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• 제19권4호
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• pp.183-206
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• 2010

The technology acceptance model (TAM) is a lot of cited in information technology adoption and usage researches. But TAM has been conducted primarily in volitional environments of the adoption of new technology. This paper discusses technology acceptance in accounting information systems to examine TAM with Characteristics of Organizations and Individuals in mandated using Combined Guard System. Combined Guard System is a scientific guard system that is composed of automated surveillance system, automated sensing system and control system. GOP Scientific Guard System is operated by GOP unit in Korean Army O Division from 2006. In this study, using the extended technology acceptance model, we have analyzed factors which affect the usage intention of GOP Scientific Guard System in mandated using environment. Based upon previous researches, we have selected Support of management unit, Training, Perceived Risk, Subjective Knowledge and Computer Self-efficacy, perceived usefulness, perceived ease of use, and usage intention as variables and proposed a research model. We collected 253 survey questionnaires from Korean army officer and soldier who are serviced at GOP unit in O Division, and analyzed the data using SPSS 12.0 and SmartPLS 2.0M3. According to the results by PLS analysis, According to the results by PLS analysis, Training and Subjective Knowledge did not affect Perceived usefulness, but the other hypotheses were accepted. And Perceived usefulness, and Ease of use influenced the Usage intention. The results of this study will increase Characteristics of Organizations and Individuals on GOP Scientific Guard System and eventually contribute to establishing the activation of Combined Guard System.

• 한국환경보건학회지
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• 제31권6호
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• pp.467-474
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• 2005

The runoff characteristics of combined sewer overflow(CSO) in the urban area of Jeonju were investigated and analyzed by using the SWMM (Storm Water Management Model) and GIS. From August to November 2004, investigations on two rainfall events were performed and flowrate, pH, BOD, COD, SS, T-N and T-P were measured. these data were used for model calibration. Using GIS technique, watershed characteristics of study area were calculated. that is, divide into sub_basin, total width, slope, make soil map etc. On the basis of the measured data and the simulation results by SWMM, it could be known that the $80-90\%$ of pollution load are discharged in early-stage storm runoff. SMC(site mean Concentration) for combined sewer system area were BOD 28.1, COD 31.5, SS 186 ppm etc. this is shown that during the rain fall, high concentration of waste was loaded to receiving water. Unit loads of combined sewer system area were BOD 306, COD 410, SS 789, T-N 79, T-P 6.8 kg/ha/yr.

• Structural Engineering and Mechanics
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• 제55권5호
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• pp.953-964
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• 2015

A model has been proposed that can predict the ultimate torsional strength of single-box multi-cell reinforced concrete box girder under combined loading of bending, shear and torsion. Compared with the single-cell box girder, this model takes the influence of inner webs on the distribution of shear flow into account. According to the softening truss theory and thin walled tube theory, a failure criterion is presented and a ultimate torsional strength calculating procedure is established for single-box multi-cell reinforced concrete box girder under combined actions, which considers the effect of tensile stress among the concrete cracks, Mohr stress compatibility and the softened constitutive law of concrete. In this paper the computer program is also compiled to speed up the calculation. The model has been validated by comparing the predicted and experimental members loaded under torsion combined with different ratios of bending and shear. The theoretical torsional strength was in good agreement with the experimental results.

• The Korean Journal of Pain
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• 제20권1호
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• pp.8-14
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• 2007

Background: Anticonvulsants and antidepressants are adjuvant analgesic drugs that are used widely for treating chronic neuropathic pain syndromes. The combined analgesic effect of gabapentin and milnacipran was investigated with a rat neuropathic pain model. Methods: The rat neuropathic pain model was made by ligating the spinal nerves (L5 and L6). An intrathecal catheter was inserted into the subarachnoid space. Tactile allodynia was tested with the up-down method using von Frey hair. We determined the antiallodynic effect of intraperitoneal (I.P.) and intrathecal (I.T.) gabapentin. The combined effect of I.P. gabapentin (50 mg/kg) and milnacipran (0, 10 and 30 mg/kg) was investigated. Results: Intraperitoneal and intrathecal administration of gabapentin increased the threshold for tactile allodynia (the ED50 was 60.6 mg/kg and $45.5{\mu}g$, respectively). Co-administration of I.P. milnacipran increased the antiallodynic effect of I.P. gabapentin in a dose-dependent fashion. Conclusion: The combined administration of milnacipran and gabapentin may increase the total analgesic effect during treatment of neuropathic pain.

• Korean Chemical Engineering Research
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• 제53권5호
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• pp.545-552
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• 2015

복합발전 공정의 모델링 및 모사는 공정의 운전 및 설계 조건에 따른 공정변수의 변화를 정량적으로 예측하기 위한 중요한 접근방법이다. 본 연구에서는 현재 사용되는 복합발전공정의 정상상태 모사기의 단점을 보완하여, 사용자의 편의성과 개발자의 핵심기술 모델링을 가능하게 하는 공정 모델링 시스템을 개발하였다. 복합발전 공정의 주요 장치들을 분석하여 수학적 모델을 개발하였으며 이를 종합하여 모델라이브러리로 구성하였다. 또한 모사의 목적과 입수 가능한 자료에 따라 사용되는 모델의 상세도가 다르다는 점을 고려하여 주요장치에 대해 다른 상세도의 모델을 개발하였다. 복합발전 상업공정을 개발된 모델링 시스템을 사용하여 모델링과 모사를 수행하였으며 모사의 결과를 데이터자료와 비교 검증하였다. 검증의 모사결과와 자료데이터는 1% 내의 오차를 보였으며 개발된 모델링 시스템이 실제 공정에 응용될 수 있음을 보여주었다.

• Advances in concrete construction
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• 제16권1호
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• pp.21-34
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• 2023

This work presents a complete optimal model for trapezoidal combined footings that support a concentric load and moments around of the "X" and "Y" axes in each column to obtain the minimum area and the minimum cost. The model presented in this article considers a pressure diagram that has a linear variation (real pressure) and the equations are not limited to some cases. The classic model takes into account a concentric load and the moment around of the "X" axis (transverse axis) that is applied due to each column, i.e., the resultant force is located at the geometric center of the footing on the "Y" axis (longitudinal axis), and when the concentric load and moments around of the "X" and "Y" axes act on the footing is considered the uniform pressure applied on the contact surface of the footing, and it is the maximum pressure. Four numerical problems are presented to find the optimal design of a trapezoidal combined footing under a concentric load and moments around of the "X" and "Y" axes due to the columns: Case 1 not limited in the direction of the Y axis; Case 2 limited in the direction of the Y axis in column 1; Case 3 limited in the direction of the Y axis in column 2; Case 4 limited in the direction of the Y axis in columns 1 an 2. The complete optimal design in terms of cost optimization for the trapezoidal combined footings can be used for the rectangular combined footings considering the uniform width of the footing in the transversal direction, and also for different reinforced concrete design codes, simply by modifying the resisting capacity equations for moment, for bending shear, and for the punching shear, according to each of the codes.

• 에너지공학
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• 제23권4호
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• pp.41-48
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• 2014

지금까지 관행적으로 액체의 누출은 순간누출과 연속누출로 분류 되어 왔다. 본 논문에서는 이러한 분류의 문제점을 인식하고 새로운 분류 방법을 찾기 위하여 제한된 시간 동안 누출되는 극저온 액체의 확산에 관한 연구를 수행하였다. 이러한 물리적 현상은 누출된 액체풀의 부피, 반경, 높이에 관한 연립방정식에 의해 지배되며, 주요 변수는 단위면적당 증발률, 누출시간, 누출량의 3 개 이다. 섭동법에 의한 해를 효율적으로 구하기 위하여 독립된 형태의 부피에 관한 2차 미분방정식을 얻었다. 이 새로운 지배 방정식은 기존의 방법에 비하여 매우 간단하게 해를 얻을 수 있게 한다. 섭동해의 결과, 동일한 누출량인 경우에 누출시간이 작으면 연속누출이 순간누출로 이어지는 혼합 형태의 누출이 되나, 누출시간이 크게 되면 연속누출 형태로만 존재하게 된다. 동일한 누출시간의 경우에는 누출량이 작으면 연속누출 형태로만 존재하지만, 누출량이 증가할수록 혼합형태의 누출로 된다. 이러한 2개의 영역을 분할하는 경계를 섭동해를 이용하여 해석적으로 제시함으로서 누출의 새로운 분류에 대한 명확한 근거를 제시 하였다.