• 한국구조물진단유지관리공학회 논문집
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• 제5권1호
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• pp.176-187
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• 2001

Most bridges have expansion joints to accommodate thermal expansion and contraction without inducing large forces in the bridges. To evaluate the effects of earthquake-induced at expansion joints of concrete bridges, the first part of this paper deals with a collinear impact between concrete segments, which have the same cross section but different lengths. Especially, impact force, momentum, strain energy and kinetic energy are formulated in mathematically. These results are then used in the second part of this paper to simulate a realistic yet simple analysis of seismic pounding in concrete bridges. Analysis of seismic pounding in idealized concrete bridges is carried out by using a simple lumped-mass model and rationally determined values of the coefficient of restitution and the duration of impact.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.945-950
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• 2001

Floor impact noise has been evaluated by investigating the temporal and spectral characteristics of the noise. The noises generated by different impactors were analyzed to find out whether there is any correlation with the factors of ACF /IACF (Autocorrelation Function/Inter-aural Cross-correlation Function) [1] and Zwicker parameters [2]. Experiments were undertaken to compare the objective and subjective parameters of the floor impact noises generated by a bang/tapping machine, a rubber ball [3], and a walker. As a result, it was found that $\phi$ (0) and IACC extracted from ACF/IACF, and Loudness, Unbiased Annoyance from Zwicker parameters showed high correlation with subjective evaluations of loudness concerning floor impact noises. In addition, it was revealed that jumping is similar to the ball.

• Elastomers and Composites
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• 제55권1호
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• pp.46-50
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• 2020

Material extrusion (ME)-type 3D printing is the most popular among the 3D printing processes. In this study, the cross-section morphologies of ME-type 3D printing manufactured specimens were observed with respect to the thermal properties of the material. The cross-section morphology of a specimen is related to the deposition strength, and the outside profile of the cross-section is related to the surface roughness. The filaments used in this study, with different thermal conductivities, were the acrylonitrile-butadiene-styrene (ABS), the high impact polystyrene (HIPS), the glycol-modified polyethylene terephthalate (PETG), and the polylactic acid (PLA). The cross-sections and the surfaces of the 3D manufactured specimens were examined. In ME-type 3D printing, the filaments are extruded through a nozzle and they form a layer. These layers rapidly solidify and as a result, they become a product. The thermal conductivity of the material influences the cooling and solidification of the layers, and subsequently the cross-section morphology and the surface roughness.

• Nuclear Engineering and Technology
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• 제54권3호
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• pp.817-825
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• 2022

A recent benchmarking effort, under the auspices of the Organization for Economic Cooperation and Development (OECD) Nuclear Energy Agency (NEA), has been made to evaluate the current state of modeling and simulation tools available to model fluoride salt-cooled high temperature reactors (FHRs). The FHR benchmarking effort considered in this work consists of several cases evaluating the neutronic parameters of a 2D prismatic FHR fuel assembly model using the participants' choice of simulation tools. Benchmark participants blindly submitted results for comparison with overall good agreement, except for some which significantly differed on cases utilizing a molybdenum-bearing control rod. Participants utilizing more recently updated explicit isotopic cross sections had consistent results, whereas those using elemental molybdenum cross sections observed reactivity differences on the order of thousands of pcm relative to their peers. Through a series of supporting tests, the authors attribute the differences as being nuclear data driven from using older legacy elemental molybdenum cross sections. Quantitative analysis is conducted on the control rod to identify spectral, reaction rate, and cross section phenomena responsible for the observed differences. Results confirm the observed differences are attributable to the use of elemental cross sections which overestimate the reaction rates in strong resonance channels.

• 무역학회지
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• 제46권6호
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• pp.211-224
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• 2021

Based on the perspective of international trade and cross-border e-commerce development, this paper explores the impact of cross-border e-commerce on international trade. This paper first describes the current situation of China's cross-border e-commerce and proposes a theoretical model of the influence of China's cross-border e-commerce on its international trade based on the research and summary of a large number of relevant documents. This paper establishes an extended gravity model based on the proposed theoretical model. Relevant data of 13 trading partner countries were used as sample data, and OLS regression analysis and heterogeneity analysis were conducted on gravity model by using Eviews 11.0. Then, in order to study the influence of each variable on import and export trade volume, import and export trade volume were respectively taken as explained variables and further studied by OLS regression analysis. To test the robustness of the model, the empirical analysis results show that cross-border e-commerce does promote the volume of China's international trade.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2002년도 추계학술발표회요약집
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• pp.303.1-303
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• 2002

• 한국산업융합학회 논문집
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• 제4권3호
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• pp.295-304
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• 2001

The hydrodynamic impact problem was studied from 1929 to recent. Especially, Impact pressure is important for the design of the ships and offshore structure and spacecrafts, and under weapons. A ship traveling at high speed or in heavy sea has its bow and bottom damaged by high pressure caused by impact with and detachment from the water surface. Considerable impact may also occur when large waves hit the cross member or deck plate of an offshore structure within the splash zone. Many engineering cases require consideration of impact pressure, the movement of objects and change of the flow field. This study was obtained the pressure distribution of a falling body that is deadrise angle $0^{\circ}$ and deadrise angle $5^{\circ}$ upon a water surface by the experiment with the impact machine. The theoretical equation was obtained the air region and the interface and the water region which devide 3 parties between the body and the water surface for an investigation of the complete phenomena. Pressure distributions and histories compare favorably with available experimental data. The numerical results are similar to the experimental results for the impact force type with Fo(1+$cos{\pi}t/tc$).

• Asian Pacific Journal of Cancer Prevention
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• 제17권11호
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• pp.5005-5009
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• 2016

Introduction: Gutkha contains harmful and carcinogenic chemicals and oral cancer caused by tobacco usage has been reported as a major preventable cause of death worldwide by the World Health Organization. The Telangana state government implemented a ban on gutkha usage starting in 2013 but how effective this ban has been remains unclear. Objectives: The objective of this study was to determine the actual impact of the gutkha ban on users and vendors. Methodology: A cross-sectional study was conducted among gutkha users and tobacco vendors in Ranga Reddy district, Telangana. Based on a pilot study the sample size was determined as 368 and 384 for users and vendors respectively. Two separate questionnaires were administered to these groups. The parameters studied mainly included knowledge regarding the ban, and its impact. Results: About 49.1% of the users were aware of the ban on gutkha. Newspapers were the main source of information regarding the ban as reported by 45.3% of users. After the ban, 29.8% of gutkha users switched to other tobacco products. Awareness of health hazards and non-availability of gutkha was the most important reason stated for quitting or reducing consumption. Conclusion: The perspective of ban when visualized from the users point of view depicted a negative impact while the vendors portrayed a positive impact. Considering the addictive potential of the ingredients of gutkha, recording the effects of the ban on regular consumers and determining whether they can still obtain the products by illicit trade, would be noteworthy for implementation of strict rules.

• Nuclear Engineering and Technology
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• 제56권4호
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• pp.1407-1424
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• 2024

In Pressurized Water Reactors, most of the failed fuel rods are often observed at the periphery of the fuel assembly, especially near the core baffle. The rod vibration-induced fretting wear is a significant failure mechanism strongly correlated with the coolant and support conditions. This paper presents a coupled vibration model of double-rod to predict the grid-to-rod fretting (GTRF) wear. A motion-dependent fluid force model is used to simulate the coolant cross flow, the gap constraints with asymmetric stiffness between spring and dimple on the vibration form, and the fretting wear are discussed. The results show the effect of the coupled vibration on the deterioration of wear, providing a sound theoretical explanation of some failure phenomena observed in the previous experiment. Exploratively, we analyze the impact of the baffle jet on the GTRF wear, which indicates that the high-velocity cross-flow will significantly affect the vibration forms while sharply changing the wear behavior.

• 정보보호학회논문지
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• 제28권3호
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• pp.695-706
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• 2018

최근 제조업을 시작으로 농업, 금융업 등의 전 산업 영역에서 ICBM(IoT, Cloud, Bigdata, Mobile)을 중심으로 한 신산업과의 융합이 급속도로 진행되고 있다. 향후 융합산업의 가장 큰 문제 중 하나인 사이버 위협에 대비하기 위해 정보보호를 고려한 융합산업의 발전이 매우 중요한 상황이다. 이에 본 연구에서는 현재 발표된 산업발전정책과 이와 관련된 정보보호정책들의 세부 내용을 교차영향분석으로 분석하고 전문가 설문을 통해 정책의 우선순위를 제시하였다. 이를 통해 정보보호정책 내의 우선순위 및 상호 연관성을 밝히고, 효과적인 정책 시행방향에 대해서 제시하고자 하였다. 결과적으로 본 연구에서 도출한 6개의 정보보호정책과제들은 모두 핵심 동인에 속하며, 정책의 중요도를 고려한다면 보안 산업의 체질개선 및 지원 강화, 정보보호 인재양성, 정보보호산업 투자확대 등의 정책이 상대적으로 우선 시행될 필요가 있는 것으로 나타났다.