• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1996년도 제11차 KACG 학술발표회 Crystalline Particle Symposium (CPS)
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• pp.285-309
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• 1996

Non oxide ceramics such as nitrides of transition metals have shown significant potential for future economic impact, in diverse applications in ceramic, aerospace and electronic industries, as refractory products, abrasives and cutting tools, aircraft components, and semi-conductor substrates amid others. Combustion synthesis has become an attractive alternative to the conventional furnace technology to produce these materials cheaply, faster and at a higher level of purity. However he process os highly exothermic and manifests complex dynamics due to its strongly non-linear nature. In order to develop an understanding of this process and to study the effect of operational parameters on the final outcome, numerical modeling is necessary, which would generated essential knowledge to help scale-up the process. the model is based on a system of parabolic-hyperbolic partial differential equations representing the heat, mass and momentum conservation relations. The model also takes into account structural change due to sintering and volumetric expansion, and their effect on the transport properties of the system. The solutions of these equations exhibit steep moving spatial gradients in the form of reaction fronts, propagating in space with variable velocity, which gives rise to varying time scales. To cope with the possibility of extremely abrupt changes in the values of the solution over very short distances, adaptive mesh techniques can be applied to resolve the high activity regions by ordering grid points in appropriate places. To avoid a control volume formulation of the solution of partial differential equations, a simple orthogonal, adaptive-mesh technique is employed. This involves separate adaptation in the x and y directions. Through simple analysis and numerical examples, the adaptive mesh is shown to give significant increase in accuracy in the computations.

• Journal of Radiation Protection and Research
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• 제34권4호
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• pp.195-200
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• 2009

원전에서는 많은 종류의 방사성물질이 생성되어 일부는 환경으로 방사성유출물로서 배출되고 있다. 이러한 방사성유출물 중에서 탄소 동위원소인 Carbon-14는 자연에서 이미 높은 준위의 백그라운드를 형성하고 있기 때문에, 원전에서 Carbon-14가 배출되더라도 환경이나 일반인의 피폭방사선량에 미치는 영향이 미미하여 과거에는 배출감시와 환경감시를 수행하지 않았다. 그런데, 핵연료 제조기술 발달과 운전방법 개선으로 핵연료로부터 불활성기체와 입자방사성물질의 방출이 계속 감소하고 있다. 또한 방사선계측기술의 향상에 따라 삼중수소와 Carbon-14 같은 저준위 베타방사능 핵종의 검출준위가 낮아져, 이들 핵종이 일반인 선량평가에서 미치는 비율이 상대적으로 높아지고 있다. 본 논문은 원자력시설에서 발생하는 Carbon-14에 대해 미국의 기술보고서와 논문 등을 검토하여 배출관리와 환경 영향평가에 대한 방사선감시의 기술적 배경을 조사하였다. 이를 바탕으로 Carbon-14 방사성핵종의 배출감시 방안에 대한 타당성을 제시하고자 하였다.

• 사회경제평론
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• 제31권2호
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• pp.71-104
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• 2018

본 연구의 목적은 포스트케인지언 내생화폐론을 통해 지역 예대율의 의미와 지방은행의 의의를 밝히는 데 있다. 포스트케인지언 내생화폐론에 따르면 은행은 자금중개기관이 아닌 대출을 통해 예금화폐를 창출하는 신용창조기관이다. 한편 은행을 자금중개기관으로 해석하는 기존 시각을 따르면 지역의 예금은행 예대율이 높을수록 예금은행에 의한 예금유입을 기반으로 대출활동이 활발하게 일어나는 것으로 해석되었다. 하지만 내생화폐론을 따르면 지역 예대율은 지역수지의 변화를 보여주는 지표로 재해석된다. 특히 지역의 높은 예대율은 지역 내에서 대출을 통해 창출된 예금이 유출되어서 지역 내 자금순환이 위축되었다는 의미로 재해석된다. 나아가 지방은행이 지니는 지역밀착형 금융관행과 신용창조 능력 그리고 실물에 미치는 영향력을 종합적으로 고려할 때 지방은행 재설립 정책을 지역균형발전의 견지에서 긍정적으로 검토할 필요가 있다.

• 한국지반환경공학회 논문집
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• 제22권10호
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• pp.13-19
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• 2021

아스팔트 포장의 균열은 날씨의 변화나 차량에 의한 충격으로 발생하며, 균열을 방치할 경우 포장 수명이 단축되고 각종 사고를 불러 일으킬 수 있다. 따라서 아스팔트 도로 포장의 균열을 빠르게 감지하여 보수조치를 취하기 위하여 이미지를 통해 균열을 자동으로 탐지하기 위한 연구들이 지속되어 왔다. 특히 최근들어 Convolutional Neural Network를 사용하여 아스팔트 도로 포장의 균열을 탐지하려는 모델들이 많이 연구되고 있으나, 고성능의 컴퓨팅 파워를 요구하기 때문에 실제 활용에는 한계가 있다. 이에 본 논문에서는 모바일 기기에 적용 가능한 스몰 딥러닝 모델을 적용하여 아스팔트 도로 포장의 균열을 탐지하는 모델의 개발을 위한 프레임워크를 제안한다. 사례연구를 통해 제안한 스몰 딥러닝 모델은 일반적인 딥러닝 모델들과 비교 연구되었으며, 상대적으로 적은 파라미터를 가지는 모델임에도 일반적인 딥러닝 모델들과 유사한 성능을 보였다. 개발된 모델은 모바일 기기나 IoT에 임베디드 되어 사용될 수 있을 것으로 기대된다.

• International Journal of Computer Science & Network Security
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• 제22권3호
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• pp.276-284
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• 2022

The research aims to study the dynamics of academic procrastination and its impact on the mental health of students during the transition to distance learning during the COVID-19 pandemic. At the beginning of the COVID-19 pandemic, it was identified a declining tendency of overall rates of academic procrastination and at the same time increase in the number of carriers of mid and high levels of academic procrastination. The decline in the general rates of academic procrastination at the beginning of 2021 testifies to the adaptation processes experienced by students to the conditions of distance learning. It was documented that students' academic procrastination is accompanied by a steady negative emotional tension. During the transition to distance learning, the intensity of students' learning activity has increased, which altogether causes stress as one of the main reasons for the academic procrastination among future psychologists. The study identified a risk of academic procrastination manifestation among students for their mental health, which provides a basis for developing and testing a program to prevent the phenomenon of academic procrastination among degree-seeking students.

• Molecules and Cells
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• 제44권11호
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• pp.830-842
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• 2021

When perceiving microbe-associated molecular patterns (MAMPs) or plant-derived damage-associated molecular patterns (DAMPs), plants alter their root growth and development by displaying a reduction in the root length and the formation of root hairs and lateral roots. The exogenous application of a MAMP peptide, flg22, was shown to affect root growth by suppressing meristem activity. In addition to MAMPs, the DAMP peptide PEP1 suppresses root growth while also promoting root hair formation. However, the question of whether and how these elicitor peptides affect the development of the vascular system in the root has not been explored. The cellular receptors of PEP1, PEPR1 and PEPR2 are highly expressed in the root vascular system, while the receptors of flg22 (FLS2) and elf18 (EFR) are not. Consistent with the expression patterns of PEP1 receptors, we found that exogenously applied PEP1 has a strong impact on the division of stele cells, leading to a reduction of these cells. We also observed the alteration in the number and organization of cells that differentiate into xylem vessels. These PEP1-mediated developmental changes appear to be linked to the blockage of symplastic connections triggered by PEP1. PEP1 dramatically disrupts the symplastic movement of free green fluorescence protein (GFP) from phloem sieve elements to neighboring cells in the root meristem, leading to the deposition of a high level of callose between cells. Taken together, our first survey of PEP1-mediated vascular tissue development provides new insights into the PEP1 function as a regulator of cellular reprogramming in the Arabidopsis root vascular system.

• The Journal of Asian Finance, Economics and Business
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• 제9권4호
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• pp.273-285
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• 2022

Using data from a departmental profit and loss management questionnaire survey conducted for a group of hospitals consisting of various establishment entities, this study evaluates the effectiveness of departmental profit and loss management practices, such as break-even analysis, based on objective performance data. The study also examines whether the implementation of departmental profit and loss accounting is still effective in improving profitability in the financial year 2021 and whether the effectiveness of the implementation of departmental profit and loss accounting is robust. This study reconfirmed that the implementation of departmental profit-and-loss accounting has a positive effect on objective financial performance in hospitals and that the effect of improving profitability can be enhanced by implementing it monthly with high frequency and regularity and by using the accounting results more actively. It was also found that the department's implementation of break-even analysis had a positive impact on financial performance, which was enhanced by more active use of the data. Given the current economic climate, a hospital organization's active participation in income statement management, not only for the hospital as a whole but also for each department, would be an effective management activity.

• International Journal of Computer Science & Network Security
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• 제22권10호
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• pp.57-66
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• 2022

The aim of the article is to investigate socio-political processes in Ukraine on the basis of institutional and behavioral approaches, in particular their regulatory and informational support. Methodology. To determine the nature and content of sociopolitical processes, the following approaches have been used: 1. Institutional approach in order to analyze the development of Ukraine's political institutions. 2. The behavioral approach has been used for the analysis of socio-political processes in Ukraine in the context of political behavior of citizens, their political activity which forms the political culture of the country. Results. The general features of the socio-political situation in Ukraine are as follows: the formed model of government, which can be conditionally described as "presidential"; public demand for new leaders remains at a high level; the society has no common vision of further development; significant tendency of reduction of real incomes of a significant part of the society and strengthening of fiscal pressure on businessmen will get a public response after some time. Increasing levels of voice, accountability, efficiency of governance and the quality of the regulatory environment indicate a slow change in the political system, which will have a positive impact on public sentiment in the future. At the same time, there has been little change in the quality of Ukraine's institutions to ensure political stability, the rule of law and control of corruption. There are no cardinal changes in the development of the institution of property rights, protection of intellectual rights, changes in the sphere of ethics and control of corruption. Thus, Ukraine's political institutions have not been able to bring about any change in the social-political processes. Accordingly, an average level of trust and confidence of citizens in political institutions and negative public sentiment regarding their perception and future change can be traced in Ukraine.

• 한국지구과학회지
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• 제43권4호
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• pp.511-519
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• 2022

Given the significant social and economic impact caused by heat waves, there is a pressing need to predict them with high accuracy and reliability. In this study, we analyzed the real-time forecast data from six models constituting the Subseasonal-to-Seasonal (S2S) prediction project, to elucidate the key mechanisms contributing to the prediction of the recent record-breaking Korean heat wave event in 2018. Weekly anomalies were first obtained by subtracting the 2017-2020 mean values for both S2S model simulations and observations. By comparing four Korean heat-wave-related indices from S2S models to the observed data, we aimed to identify key climate processes affecting prediction accuracy. The results showed that superior performance at predicting the 2018 Korean heat wave was achieved when the model showed better prediction performance for the anomalous anticyclonic activity in the upper troposphere of Eastern Europe and the cyclonic circulation over the Western North Pacific (WNP) region compared to the observed data. Furthermore, the development of upper-tropospheric anticyclones in Eastern Europe was closely related to global warming and the occurrence of La Niña events. The anomalous cyclonic flow in the WNP region coincided with enhancements in Madden-Julian oscillation phases 4-6. Our results indicate that, for the accurate prediction of heat waves, such as the 2018 Korean heat wave, it is imperative for the S2S models to realistically reproduce the variabilities over the Eastern Europe and WNP regions.

• Ocean and Polar Research
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• 제45권3호
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• pp.103-111
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• 2023

To evaluate the impact of effluents from land-based fish farms on the coastal ocean of Wando, Korea, we analyzed inorganic nutrients, particulate organic carbon (POC), dissolved organic carbon (DOC), and colored dissolved organic matter (CDOM) in the effluent and influent of land-based fish farms during the summer (July) of 2021. The average concentrations of nutrients (Dissolved inorganic nitrogen, phosphorus, and silicate; DIN, DIP, and DSi, respectively) in the effluents of this study area were 17±3.7 μM, 1.4±0.7 μM, and 14±1.6 μM, respectively. The average concentrations of POC and DOC were 37±22 μM and 81±13 μM, respectively, with POC accounting for about 30% for total organic carbon in effluents. The Reduced Dissolved Inorganic Nitrogen/Total Dissolved Inorganic Nitrogen ratio (0.7), potential short-period index, indicates that the discharge of nutrients excreted by the fish and unconsumed feed into coastal water results in such nutrients being deposited and accumulated in the sediment. Subsequently, this continuous accumulation triggers the release of ammonium ions during organic matter decomposition, and the ammonium-enriched waters that encroach on fish farms as influent seem to be due to the diffusion of high concentrations of ammonium from bottom sediment. Furthermore, we used fluorescence indices to examine the characteristics of organic matter sources, obtaining mean values of 1.54±0.19, 1.06±0.06, and 1.56±0.06 for the humification index, biological index, and fluorescence index, respectively, in the effluent. These results indicate that the organic matters had an autochthonous origin that resulted from microbial decomposition, and such organic matters were rapidly generated and removed by biological activity, likely supplied from the sediment. Our results suggest that the effluent from land-based fish farms could be a potential source of deoxygenation occurrence in coastal areas.