• Wind and Structures
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• 제35권2호
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• pp.83-92
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• 2022

When the rolling stocks run on the curve, the external rail has to be lifted to a certain level to balance the centrifugal force acting on the train body. Under such a situation, passengers may feel uncomfortable, and the slanted vehicle has the potential overturning risks at high speed. This paper conducted a wind tunnel test in an annular wind tunnel with φ=3.2 m based on a 1/20^th scaled high-speed train (HST) model. The sensitivity of Reynolds effects ranging from Re = 0.37×10⁶ to Re = 1.45×106 was tested based on the incoming wind from U=30 m/s to U=113 m/s. The wind speed covers the range from incompressible to compressible. The impact of roll angle ranging from γ=0° to γ=4° on train aerodynamics was tested. In addition, the boundary layer development was also analyzed under different wind speeds. The results indicate that drag and lift aerodynamic coefficients gradually stabilized and converged over U=70 m/s, which could be regeared as the self-similarity region. Similarly, the thickness of the boundary layer on the floor gradually decreased with the wind speed increase, and little changed over U=80 m/s. The rolling moment of the head and tail cars increased with the roll angle from γ=0° to γ=4°. However, the potential overturning risks of the head car are higher than the tail car with the increase of the roll angle. This study is significant in providing a reference for the overturning assessment of HST.

• 정보보호학회논문지
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• 제31권6호
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• pp.1291-1307
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• 2021

국가 배후의 사이버공격 활동이 갈수록 증가하고 있으며, 국가 배후의 사이버공격은 개인 및 민간단체의 공격에 비해 규모와 영향이 커서 국가안보를 위협하고 있다. 이에 미국·영국을 비롯한 주요국과 EU·OECD 등 국제기구는 사이버공격에 대해 비례적 대응을 권고하고 있다. 우리나라도 2019년에 국가사이버안보전략을 발표하고, 사이버공격에 대한 억지력 확보를 위한 능동적 대응 의지를 밝혔다. 그러나 이후 관련된 정책이나 제도가 마련된 적이 없으며, 사이버공격 발생 시 비례적 대응을 위한 심각도 평가 및 대응방안이 미비한 상황이다. 본 논문에서는 국가 차원에서 사이버공격에 대한 대외 대응기준을 마련하고, 대응 시 비례적 대응이 가능하도록 피해의 규모와 영향을 측정할 수 있는 방법론을 제안한다. 또한, 제안하는 심각도 평가방법론을 이용해 한국 공격사례에 대해 심각도 평가를 수행하였으며, 평가결과를 기반으로 한국의 사이버위협 동향 및 심각도별 사이버공격 대응방안을 분석하였다.

• 한국콘텐츠학회논문지
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• 제22권3호
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• pp.488-499
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• 2022

본 연구는 우리나라의 과학기술정책과 정부출연연구기관(이하, 출연(연))의 연구계획 사이의 연관 관계에 관한 분석을 시도하였다. 국가과학기술혁신체제(NIS)에서 주요 행위자인 출연(연)이 수행하는 연구사업은 정부의 과학기술정책 방향과 밀접한 관계를 가진다. 특히, 우리나라의 출연(연)은 1973년 '특정연구기관육성법'에 근거하여 전략기업의 기술수요를 해결하는 등 과학기술입국의 구심축 역할을 해왔다. 이에 출연(연)의 연구개발(R&D) 전략 변화에 영향을 주는 주요 요인 중 정부의 과학기술정책이 어떠한 영향을 미치는가를 살펴보고자 한다. 이를 위해 텍스트 마이닝(text mining), 군집군석(cluster analysis) 등의 계량정보분석을 통해 과학기술정책과 과학기술 분야 출연(연)인 한국과학기술정보연구원(KISTI)의 연구성과계획 간의 연관 관계를 분석했다. KISTI R&D 성과계획 핵심어에 대한 계량분석 분석결과 정부의 과학기술 정책변화가 출연(연)의 R&D 사업계획에 영향을 미치는 것으로 나타났다. 과학기술기본계획은 시기별 각 정부가 추구한 과학기술 비전에 따라 정책 패러다임, 과학기술 행정체계가 변화하였고, 그에 따라 출연(연)에 대한 관리체계 변화와 역할·임무의 변화에 영향을 미친 것으로 나타났다. 본 연구를 통해 기존 연구에서 제시한 과학기술정책이 출연(연)의 연구성과계획에 영향을 미치는 요인에 대한 상관관계를 실증적으로 분석한 데에 그 의의가 있다.

• International Journal of Computer Science & Network Security
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• 제22권3호
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• pp.53-60
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• 2022

The article examines the problems of ensuring the effectiveness of the economic security system in the face of increasing competition. The relevance of the study is determined by the intensification of competition between enterprises and the threats arising from this phenomenon. The methodological basis is the methods used: analysis and synthesis - to identify the main trends in the development of tools for economic security of the enterprise; systematization - to highlight the main characteristics of the economic security of the enterprise in the intensification of competition; generalization - to form the general conclusions of the study. The purpose of scientific research is to substantiate the feasibility of using the tools of the economic security system to increase its efficiency in the face of intensifying competition. The main components of the economic security system of the enterprise, which have the greatest impact on the formation of an effective level of economic security. The defining characteristics of the system of economic security of the enterprise are investigated. Special characteristics of the economic security system of the enterprise are considered. The offered directions of tools of maintenance of system of economic safety of the enterprise in competitive conditions: objective, subjective external, subjective internal. For each area, specific tools for ensuring the system of economic security, which affect its efficiency, have been identified.

• 한국콘텐츠학회논문지
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• 제22권2호
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• pp.593-604
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• 2022

본 연구는 기업의 노동투자비효율성에 대한 감사인의 반응에 대해 분석하였다. 구체적으로 노동투자비효율성이 감사보수와 감사시간에 미치는 영향에 대해 검증하였다. 비효율적인 노동투자가 이루어지는 기업일수록 감사인들은 사업위험을 높게 평가하여 감사위험이 증가한 것으로 인식하게 된다. 이로 인해 높아진 감사위험을 낮추기 위해 감사범위를 확대하고 충분한 감사증거를 수집하려는 유인이 있다. 따라서 감사인들은 더 높은 감사보수를 요구하고, 추가된 감사노력으로 인해 감사시간이 증가할 것으로 예상된다. 2002년부터 2018년까지 유가증권시장 및 코스닥시장에 상장된 기업을 대상으로 분석한 결과, 노동투자에 대한 비효율성이 증가할수록 감사보수와 감사시간은 증가하는 것으로 나타났다. 이러한 결과는 감사인들이 노동투자의 비효율성이 높은 기업에 대해 사업위험이 높은 것으로 평가하여 이에 대한 보상으로 높은 감사보수를 요구한다는 것으로 해석된다. 또한 감사인들이 감사위험을 낮추기 위해 추가적인 감사시간을 투입한다는 것을 시사하고 있다. 본 연구는 기업의 경쟁력을 결정하는 중요한 요소인 인력에 대한 투자가 비효율적으로 이루어지는 경우 감사보수와 감사시간이 증가한다는 실증적인 근거를 제시하였다는 점에서 공헌점을 찾을 수 있다.

• 보존과학회지
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• 제38권4호
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• pp.277-288
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• 2022

'Eve 58-1', the subject of this study is a statue made of plaster and its structural stability was evaluated by utilizing the CAE program in order to prevent the risk of damage arising from impact and vibration that are generated during the packaging and transportation process given its material characteristics. CAE is an abbreviation for Computer Applied Engineering for realization by predicting changes at the time of application of virtual physical energy. It is applied by reflecting the physical property conditions and each boundary condition of plaster, and the digital images of the internal and external structure of the work were acquired through 3D scanning and CT analysis for interpretation by executing finite element modeling. When acceleration is applied to the work in the direction of its own weight, the left-right side and the front-rear side, it was possible to confirm a maximum displacement value of 15.24 mm in the head section of the front-rear side direction that has been tilted by approximately 27° from the Y-axis and the largest stress value of 12.46 MPa was at the left ankle section. The corresponding results confirmed that the left ankle section is the most vulnerable area and the section for which precautions need to be exercised and supplemented at the time of transporting the work by means of objective values.

• BMB Reports
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• 제55권10호
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• pp.512-517
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• 2022

Traumatic brain injury (TBI) is brain damage which is caused by the impact of external mechanical forces. TBI can lead to the temporary or permanent impairment of physical and cognitive abilities, resulting in abnormal behavior. We recently observed that a single session of early exercise in animals with TBI improved their behavioral performance in the absence of other cognitive abnormalities. In the present study, we investigated the therapeutic effects of continuous exercise during the early stages of TBI in rats. We found that continuous low-intensity exercise in early-stage improves the locomotion recovery in the TBI of animal models; however, it does not significantly enhance short-term memory capabilities. Moreover, continuous early exercise not only reduces the protein expression of cerebral damage-related markers, such as Glial Fibrillary Acid Protein (GFAP), Neuron-Specific Enolase (NSE), S100β, Protein Gene Products 9.5 (PGP9.5), and Heat Shock Protein 70 (HSP70), but it also decreases the expression of apoptosis-related protein BAX and cleaved caspase 3. Furthermore, exercise training in animals with TBI decreases the microglia activation and the expression of inflammatory cytokines in the serum, such as CCL20, IL-13, IL-1α, and IL-1β. These findings thus demonstrate that early exercise therapy for TBI may be an effective strategy in improving physiological function, and that serum protein levels are useful biomarkers for the predicition of the effectiveness of early exercise therapy.

• Current Photovoltaic Research
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• 제11권3호
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• pp.67-74
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• 2023

The earth-abundant element-based Cu₂ZnSn(S,Se)₄ (CZTSSe) thin film solar cells (TFSCs) have attracted greater attention in the photovoltaic (PV) community due to their rapid development in device power conversion efficiency (PCE) >13%. In the present work, we demonstrated the fine-tuning of the bandgap in the CZTSSe TFSCs by altering the sulfur (S) to the selenium (Se) chalcogenide ratio. To achieve this, the CZTSSe absorber layers are fabricated with different S/(S+Se) ratios from 0.02 to 0.08 of their weight percentage. Further compositional, morphological, and optoelectronic properties are studied using various characterization techniques. It is observed that the change in the S/(S+Se) ratios has minimal impact on the overall Cu/(Zn+Sn) composition ratio. In contrast, the S and Se content within the CZTSSe absorber layer gets altered with a change in the S/(S+Se) ratio. It also influences the overall absorber quality and gets worse at higher S/(S+Se). Furthermore, the device performance evaluated for similar CZTSSe TFSCs showed a linear increase and decrease in the open circuit voltage (V_oc) and short circuit current density (J_sc) of the device with an increasing S/(S+Se) ratio. The external quantum efficiency (EQE) measured also exhibited a linear blue shift in absorption edge, increasing the bandgap from 1.056 eV to 1.228 eV, respectively.

• PNF and Movement
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• 제21권1호
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• pp.37-45
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• 2023

Purpose: Whiplash-associated disorder is often caused by external impact, such as a car accident, and it involves acceleration and deceleration of the flexion and extension of the neck. The purpose of this study is to determine whether the combination of cyrotherapy and a joint mobilization intervention in patients with acute whiplash-associated disorder is effective for pain, cervical range of motion (ROM), and muscle tone in the neck muscles. Methods: In this study, 20 patients with acute whiplash-associated disorder were randomly assigned to two groups. Group A was treated with cyrotherapy for 5 minutes, while group B was treated with cyrotherapy and a joint mobilization intervention. In both groups, visual analogue scale (VAS), neck disability index (NDI), cervical ROM, and muscle tone values were measured pre- and post-intervention. Results: According to the VAS values, both groups showed significant differences pre- and post-intervention (p<0.05), and in both groups, NDI was significantly decreased pre- and post-intervention (p<0.05). Finally, in terms of muscle tone, both groups showed significant changes before and after the intervention (p<0.05). Conclusion: These results showed that cryotherapy and joint mobilization can be effective interventions in patients with whiplash-associated disorder. In addition, to improve the ROM of the cervical joint and reduce NDI, the combination of cryotherapy and joint mobilization is considered more effective than the single intervention of cryotherapy.

• 급식외식위생학회지
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• 제4권1호
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• pp.7-20
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• 2023

This study was conducted to investigate the impact of refrigerator type and temperature fluctuations on the quality changes of refrigerated foods. Phycochemical and sensory quality, as well as microbial growth, were measured for various foods stored in open- or door-type refrigerators set at 5℃ during storage. The average temperatures recorded were 11.50±1.14℃ in an open refrigerator, and 6.34±0.97℃ in a closed refrigerator. The average surface temperatures of the food items were 9.60±1.20 and 6.00±0.80℃ for open and closed refrigerators, respectively. Significant changes in color and appearance quality were observed in lettuce, mackerel, ground beef, and cut pineapples when stored in open refrigerators. Ready-to-Eat foods such as gimbap and sandwiches exhibited higher levels of microbiological proliferation when stored in open refrigerators compared to closed refrigerators. Processed foods, such as sterilized milk and packaged tofu, did not show significant differences in quality among various types of refrigerators. The installation of refrigerator doors can effectively minimize temperature fluctuations caused by external factors, thereby reducing variations in food quality. These findings provide essential insights into the quality changes associated with the implementation of refrigerator doors, serving as fundamental data for ensuring optimal food preservation.