• Journal of Korean Society of societal Security
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• v.1 no.3
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• pp.59-67
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• 2008

The most influential facility causing traffic disaster on the urban road is intersection. Accordingly, this study elected a region for case study from seabang three-way junction, partial section of Dongmoon Ro in Kwang-Ju city, to the intersection of Mudeung Library Entrance. It is believed that the signal progression is very effective on the basis of short interval of intersection and massive traffic volume. The signal progression was simulated by using TRANSYT-7F model. The following is summary of the simulation: According to the change of cycle length, P.I. delay and fuel consumption showed the tendency of being increased in case that cycle length becomes long or short, centering around the best cycle length. In the event of progressing the cycle length, the average speed per vehicle is increased by 11.39Km per hour and P.I value is improved by 40.65% so that it resulted in 42.86% improvement in the total travel time. Moreover, the fuel consumption in line with the progression practice produced fuel saving of 31.04%.

• Journal of Korea Water Resources Association
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• v.40 no.11
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• pp.877-886
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• 2007

An urban drainage system consists of two major systems : flood drainage facilities and operating practices. The facilities are composed of sewer networks, gates, and pumping stations and the operating practice consists of pump or gate operation. Then, a real time simulation system which is able to simulate urban runoff and the pump operation and to consider the backwater effect is required to operate efficiently the pump. With this system, the efficient pump operating rule can be developed to diminish the possible flood damage on urban areas. In this study, a real time simulation system was developed using the SWMM 5.0 DLL and Visual Basic 6.0 equipped with EXCEL. Also, for developing efficient pump operating Rules, two new Rules were suggested. The first Rule is designed to operate pumps considering the condition of sewer networks such as depths of each junction. The second is to discharge all the amount of inflow at each time step. Results obtained by those Rules were compared with one by the current pump operating Rule which is able to consider only the depth of the retard basin. The developed model was applied to Joonggok retard basin and verified their applicability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.4C
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• pp.413-423
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• 2003

The CMA algorithmis most widely investigated blind algorithm and the most widely used one in practice. But, since nonlinear CM cost function have not closed form solution about the optimum weight. There have been difficultiesto analyze the CMA equalizer's theoretical performance. Recently, Zeng presents the notable theoretical resultabout the MSE of CM-minimizing estimators for the FIR linear channel in the presence of AWGN. Through this method, It wouldbe possible to campare the theoretical performance between CMA and Wiener equalizer in terms of MSE. In this paper, based on Zeng's method, we first calculate the theoretical MSE bound of CMA equalizer in partial response channel which is widely used in HDD, digital VCR such as high-density digital recording.playback systems. We confirmedthis result withthe computer simulation. Except this, we also performedthe theoretical and simulation analysis about the modified CMA equalizer, which was proposed to improve the performance of CMA equalizer in partial response channel. Finally, we compare and evaluate the performance analysis results between CMA and Modified CMA equalizer.

• Journal of Korean Theatre Studies Association
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• no.49
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• pp.133-169
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• 2013

Reexamining Brecht's theoretical hypotheses in terms of cognitive science, this essay arrived at several temporary interpretations. Cognitive science implies that empathy can precede the rational understanding in Verfremdungseffekt. The spectator tends to simulate the unfamiliar incident and character and feels the consequential embodied emotion that leads to the cognitive understanding. The similar situation can be found in social gestus. According to cognitive science, gesture(social gestus) is simulated in the mirror-neuron of spectator, arousing consequently the embodied emotion that triggers the succeeding understanding. The spectator apts to experience and feel physically the moving gesture before decoding it as a social signification. Brecht's intention that attempts to reveal the duality of actor and character by eliminating the fourth wall is negated by cognitive science. According to the theory of conceptual blending, the spectator under the eliminated fourth wall mixes actor and character, and simulates this blending image so that he experiences it imaginatively. As such, another kind of illusion can be formed when a fourth wall is collapsed. Meanwhile, the critical thinking of spectator Brecht wanted can be hard to occur during the performance. It is necessary for the spectator to recollect the bygone dialogue and action in terms of social context as if he presses the pause, stopping the playback while watching a play in video. In this respect the social meaning Brecht intended can be achieved more effectively by the stop motion like tableau. It would not only give the time for the spectator to consider the implied social signification, but also make him possible to decode a semiotic meaning as if interpreting a still picture. Or it can be delivered by the dialogue that expresses the playwright's critical judgement. In this case, the subject of critical thinking is not the spectator but the author. The alternative explanation that the cognitive science suggests illuminates theoretically the reasons why Brecht's theory fails to be realized in practice. In a sense, Brecht's theory is nothing but a theoretical hypothesis. It takes the premise that the emotion hinders the rational thinking, understanding emotion and reason oppositively like Plato. This assumption is negated easily by the recent cognitive science that sees the reason as a by-product of physical experience including emotion. The rational understanding, in this sense, begins from the embodied emotion. As such the cognitive science denies the dichotomy of emotion and reason that Brecht adopted. The theoretical hypothesis of cognitive science makes us recognize again the importance of bodily experience in theatre. In theatre the spectator tends to experience physically before decoding the intellectual meaning. The spectator Brecht wanted, therefore, is far from the reality. The spectator usually experiences and reacts physically before decoding the meaning critically. Thus Brecht's intention can be realized by the embodied emotion resulted from simulation. This tentative interpretation suggests that we need to pay more attention to the empirical study of spectatorship, not remaining in a speculative study.

• Smart Media Journal
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• v.9 no.4
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• pp.152-161
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• 2020

In the construction, VR(Virtual Reality) is simply used by users to implement and experience 3D modeling in virtual reality, such as safety, practical education, and promotion. The VR related research includes content development and visualization simulation such as disaster safety evacuation simulation and design education contents. Research on developing suitable VR and presenting directionality is insufficient, which is required in practice. Therefore, in this study, prior to the development of VR suitable for the construction, quantitative evaluation, and analysis based on the judgment of experts are performed. However, the research was conducted on the design stages, which are believed to have high needs and application effects of VR during the lifecycle of construction. There are nine tasks that can be applied to VR in the design stage, and these tasks were evaluated and analyzed using IPA(Importance Performance Analysis) by surveying the level of expectations, importance, and performance. As a result, it was evaluated and analyzed that VR and content development was necessary for the review of member interference and collaboration work for decision making among related stakeholders. The results of this study are expected to be used as basic data for the development of VR to be applied in the design stage to the future.

• Journal of Korea Water Resources Association
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• v.54 no.6
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• pp.443-452
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• 2021

The authors obtained the discrete hedging rule for a reservoir's water supply operation by applying mixed-integer programming to save more water by earlier rationing of water supply for a drought period. The 'water supply adjustment guide' is the current operational method applied to the multipurpose reservoirs, and it was derived by a simulation method. Applying the two rules to the Hapcheon multipurpose dam's reservoir simulations with the inflow record from 2003 to 2018, the water supply deficit occurred for the long drought from 2015 to 2018. Especially, the no water supply or intermittent water supply persisted for the second half of 2017. The water supply adjustment guide had the 'normal water supply recovery threshold on storage,' which resulted in the water supply being unavailable in July 2017; then, the water supply suspension occurred until January 2018, when the reservoir storage was greater than the normal water supply recovery threshold. Despite the storage increasing due to the inflow of water into the reservoir, the suspension occurrence needs to be improved in practice. The current water supply adjustment guide and the discrete hedging rule for a reservoir's water supply operation are useful and realistic as the reservoir operation guide, which shows the concept of reducing water supply during the drought phase as scientific figures. However, to improve the reservoir simulation results, which do not provide any or intermittent water for several months, it is necessary to increase the current water supply reduction for drought phases.

• Journal of the Korean Society of Radiology
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• v.17 no.1
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• pp.25-30
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• 2023

As 3D printing technology is used in the medical field, interest in metal materials is increasing. The Department of Radiation Oncology uses a shielding block to shield the patient's normal tissue from unnecessary exposure during electron beam therapy. However, problems such as handling of heavy metal materials such as lead and cadmium, reproducibility according to skill level and uncertainty of arrangement have been reported. In this study, candidate materials that can be used for metal 3D printing are selected, and the physical properties and radiation dose of each material are analyzed to develop a customized shielding block that can be used in electron beam therapy. As candidate materials, aluminum alloy (d = 2.68 g/cm³), titanium alloy (d = 4.42 g/cm³), and cobalt chromium alloy (d = 8.3 g/cm³) were selected. The thickness of the 95% shielding rate point was derived using the Monte Carlo Simulation with the irradiation surface and 6, 9, 12, and 16 energies. As a result of the simulation, among the metal 3D printing materials, cobalt chromium alloy (d = 8.3 g/cm³) was similar to the existing shielding block (d = 9.4 g/cm³) in shielding thickness for each energy. In a follow-on study, it is necessary to evaluate the usefulness in clinical practice using customized shielding blocks made by metal 3D printing and to verify experiments through various radiation treatment plan conditions.

• Journal of Navigation and Port Research
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• v.46 no.4
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• pp.359-366
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• 2022

While the Forward Freight Agreement (FFA) has emerged as an effective hedging tool since early 1990, the basis risk and cash flow distortions have been addressed as obstacles to the active use of FFAs. This research analyses the basis risk of FFAs and provides a feasible suggestion to reduce it. Basis risk is divided into timing basis, route basis, size basis, and low liquidity basis. The timing basis is defined as the difference between the physical hire, fixed on the specific contract date and the FFA settlement price, calculated by averaging spot rates for a certain period. Timing basis is considered the worst in eroding the effectiveness of FFAs. This paper suggests a change of hire payment criterion from contract date to 15-day moving average, as a means of mitigating the basis risk, and analyzed the effectiveness through historical simulation. The result revealed that the change is effective in mitigating the timing basis. This study delivers a meaningful implication to shipping practice in that the change of hire payment criterion mitigates the basis risk and eventually activates the use of FFAs in the future.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6C
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• pp.367-377
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• 2008

As part of study to develop LRFD (Load and Resistance Factor Design) codes for foundation structures in Korea, resistance factors for static bearing capacity of driven steel pipe piles were calibrated in the framework of reliability theory. The 57 data sets of static load tests and soil property tests conducted in the whole domestic area were collected and these load test piles were sorted into two cases: SPT N at pile tip less than 50, SPT N at pile tip equal to or more than 50. The static bearing capacity formula and the Meyerhof method using N values were applied to calculate the expected design bearing capacities of the piles. The resistance bias factors were evaluated for the two static design methods by comparing the representative measured bearing capacities with the expected design values. Reliability analysis was performed by two types of advanced methods: the First Order Reliability Method (FORM), and the Monte Carlo Simulation (MCS) method using resistance bias factor statistics. The target reliability indices are selected as 2.0 and 2.33 for group pile case and 2.5 for single pile case, in consideration of the reliability level of the current design practice, redundancy of pile group, acceptable risk level, construction quality control, and significance of individual structure. Resistance factors of driven steel pipe piles were recommended based on the results derived from the First Order Reliability Method and the Monte Carlo Simulation method.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1C
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• pp.19-29
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• 2008

As a part of study to develop LRFD (Load and Resistance Factor Design) codes for foundation structures in Korea, reliability analyses for driven steel pipe piles are performed and the target reliability indices are selected carefully. The 58 data sets of static load tests and soil property tests conducted in the whole domestic area were collected and analyzed to determine the representative bearing capacities of the piles. The static bearing capacity formula and the Meyerhof method using N values are applied to calculate the expected design bearing capacity of the piles. The resistance bias factors were evaluated for the two static design methods by comparing the representative bearing capacities with the design values. Reliability analysis was performed by two types of advanced methods: First Order Reliability Method (FORM), and Monte Carlo Simulation (MCS) method using resistance bias factor statistics. The static bearing capacity formula exhibited relatively small variation, whereas the Meyerhof method showed relatively high inherent conservatism in the resistance bias factors. Reliability indices for safety factors in the range of 3 to 5 were evaluated respectively as 1.50~2.89 and 1.61~2.72 for both of the static bearing capacity formula and the Meyerhof method. The target reliability indices are selected as 2.0 and 2.33 for group pile case and 2.5 for single pile case, based on the reliability level of the current design practice and considering redundancy of pile group, acceptable risk level, construction quality control, and significance of individual structure.