• 설비공학논문집
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• 제16권3호
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• pp.303-309
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• 2004

In order to improve thermal comfort in the Rotunda, which is high and wide visiting space of the new national museum of Korea, eight ventilating fans were installed near the ceiling of Rotunda. It has been analyzed thermal comfort of Rotunda with/without ventilating fans by numerical simulation. To evaluate thermal comfort of the Rotunda, well-known indices, PMV and PPD were introduced. The results of present investigation show that temperature distribution of the case with fans is closer to target temperature than the case with-out fans at the breathing zone. In the case without fans, thermal stratification with 16$^{\circ}C$ of temperature difference occurs along the height of the Rotunda which makes the thermal environment worse and the PPD values reach up to 50% in the 6th floor connection passage. In the case with fans, however, the vertical temperature difference were reduced to 9$^{\circ}C$ and the PPD values were lower below 20%. Consequently, the ventilating fans adopted on this study are effectively used for improving the thermal comfort in large space structure with thermal stratification.

• Steel and Composite Structures
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• 제42권3호
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• pp.315-323
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• 2022

Shear connectors are key elements that ensure integrity in a composite system. The primary purpose of a shear connector is to bring a high degree of interaction between composite elements. A wide variety of connectors are available for hot-rolled composite construction, connected to the beam through welding. However, with cold-formed members being very thin, welding of shear connectors is not desirable in cold-formed composite constructions. Shear connectors for cold-formed elements are limited in studies as well as in the market. Hence in this study, three different types of shear connectors, namely, single-channel, double channel, and self-tapping screw, were considered, and their performance assessed by the Push-out test as per Eurocode 4. The connection between channel shear connectors and the beam was made using self-tapping screws to avoid welding. The performance of the connectors was analyzed based on their ultimate capacity, characteristic capacity, ductility, and slippage during loading. Strength to weight ratio was also carried out to understand the proposed connectors' suitability for conventional ones. The results showed relatively higher initial stiffness and ductility for double channel connectors than other connectors. Also, self-tapping screws had a higher strength to weight ratio with low ductility.

• The Journal of Asian Finance, Economics and Business
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• 제8권9호
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• pp.219-233
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• 2021

This study would prove the logic that business practice CSR has a positive impact on efficient product value while philanthropic CSR has a positive impact on socio-ethical product value to promote product purchase intention. It would also test the mediating role of efficient product value and socio-ethical product value. Methods: AMOS 22.0 was used to analyze the structural equation model in this work, and the hypotheses were tested after setting the impact of corporate variables on intrinsic variables additionally. Results: This study conducted research that has not been attempted in the preceding studies, classifying CSR into business practice CSR activities related to economic, legal, and ethical responsibilities and philanthropic CSR activities related to the contribution to the community, the connection of donation and business, company-wide philanthropy, and appropriate donation performance. Conclusion: This study would prove the logic that business practice CSR has a positive impact on efficient product value while philanthropic CSR has a positive impact on socio-ethical product value to promote product purchase intention, and evaluating the mediating role of efficient product value and socio-ethical product value, thus providing implications from a new perspective that has not been explored in previous marketing studies.

• Journal of Plant Biotechnology
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• 제48권4호
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• pp.228-235
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• 2021

The amino acids found in plants play important roles in protein biosynthesis, signaling processes, and stress responses, and as components in other biosynthesis pathways. Amino acid degradation helps maintain plant cells' energy states under certain carbon starvation conditions. Branched-chain amino acid transferases (BCATs) play an essential role in the metabolism of branched-chain amino acids (BCAAs) such as isoleucine, leucine and valine. In this paper, we performed genome-wide RNA-seq analysis using CsBCAT7-overexpressing Arabidopsis plants. We observed significant changes in genes related to flowering time and genes that are germination-responsive in transgenic plants. RNA-seq and RT-qPCR analyses revealed that the expression levels of some BCAA catabolic genes were upregulated in these same transgenic plants, and that this correlated with a delay in their senescence phenotype when the plants were placed in extended darkness conditions. These results suggest a connection between BCAT and the genes implicated in BCAA catabolism.

• 공학교육연구
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• 제26권5호
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• pp.17-28
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• 2023

Generative AI has arrived and it's here. Education, research, industry, and labor are all on edge about the changes it will bring. It is noteworthy that while there is a wide range of optimistic and pessimistic predictions about the impact of generative AI, there is more concern than hope when it comes to education. This paper focuses on the lack of discussion on the impact of AI in higher education. First, we reviewed the process of the emergence of generative AI and introduced how the impact of AI is being understood from various perspectives. Second, we classified work areas based on expertise and efficiency and analyzed the impact of AI on work in each area. Finally, the study found that the educational perception of generative AI and the way it is perceived for engineering education purposes can be very different. It also argued that there is a lack of active discussion and debate on areas that need to be specifically discussed around generative AI. This has led to a phenomenon known as professors' delayed indifference. We emphasized that it is time for a serious and realistic discussion on the connection and integration of AI and education.

• Nuclear Engineering and Technology
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• 제55권8호
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• pp.2873-2878
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• 2023

The purpose of this study is to perform radiation monitoring by acquiring gamma images and real-time optical images for ^99mTc vial source using charge couple device (CCD) cameras equipped with the proposed compact gamma camera. The compact gamma camera measures 86×65×78.5 mm³ and weighs 934 g. It is equipped with a metal 3D printed diverging collimator manufactured in a 45 field of view (FOV) to detect the location of the source. The circuit's system uses system-on-chip (SoC) and field-programmable-gate-array (FPGA) to establish a good connection between hardware and software. In detection modules, the photodetector (multi-pixel photon counters) is tiled at 8×8 to expand the activation area and improve sensitivity. The gadolinium aluminium gallium garnet (GAGG) measuring 0.5×0.5×3.5 mm³ was arranged in 38×38 arrays. Intrinsic and extrinsic performance tests such as energy spectrum, uniformity, and system sensitivity for other radioisotopes, and sensitivity evaluation at edges within FOV were conducted. The compact gamma camera can be mounted on unmanned equipment such as drones and robots that require miniaturization and light weight, so a wide range of applications in various fields are possible.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 춘계학술대회
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• pp.609-611
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• 2022

LMS는 교육 학습 활동의 관리를 자동으로 해주는 소프트웨어로 코로나 확산으로 온라인 교육이 증가하고 있는 요즘 대부분의 교육 기관에서 사용되고 있다. LMS는 온라인 수업 뿐만 아니라 오프라인 수업과 연결지어 활용할 수 있을 만큼 활용도가 높고 광범위한 방식을 포괄하고 있다. 따라서 사회적 거리두기가 지속되었던 기간 동안 교육 기관 뿐만 아니라 재택근무 등 온라인 업무를 보기 위한 직장인에게도 유용한 소프트웨어임을 확인할 수 있었다. 이러한 LMS 기능은 향후 교육 시장과 온라인 클래스의 발전에 큰 도움이 될 것이다.

• 천문학회보
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• 제45권1호
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• pp.46.2-46.2
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• 2020

Dust ejection activities have been discovered from a few tens of asteroids since the first confirmation in 2006. Those objects are known as active asteroids. They provide good observational chances to study ongoing phenomena in the solar system such as sublimation of icy volatiles, mutual collisions among asteroids, rotational disintegrations, thermal fatigue, etc. Although dust ejection mechanisms of individual cases have been investigated through observations, the frequencies of the events and their connection to the overall evolutionary budget of the solar system have not yet been studied thoroughly, mainly because previous studies were based on serendipitous discoveries without any systematic surveys of these objects. In this work, we made wide-field monitoring observations of asteroids using Korea Microlensing Telescope Network (KMTNet) during the 2018/2019 winter season. Among 3,644 asteroids in the field-of-view, we detected nine candidates of brightness enhancements which we suspect as possible activities. It is still possible that some of those brightness increases have caused by long-term rotations. However, our observed frequency and brightness enhancements size-frequency distribution agrees with the expectations from impacts with decimeter sized objects, when the main belt objects size-frequency distribution observed down to decameter sized bodies are extrapolated to decimeter size.

• 천문학회보
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• 제46권1호
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• pp.54.3-54.3
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• 2021

The Coma cluster serves as an ideal laboratory to study the cluster assembly history. It is known as a typical example of relaxed galaxy clusters. However, recent X-ray, radio and optical observations revealed a number of substructures in Coma. The NGC 4839 group is an interesting substucture in the sense that it is overlappled with the X-ray bright component in the south-west region. Recent hydrodynamical simulations in the literature suggest that the NGC 4839 group came from the north-east direction of Coma, passed the apocenter about 1 Gyr ago, and started a second infall to the Coma core recently. Interestingly a number of E+A galaxies are located along the filament connecting the NGC 4839 group and the Coma core. We are surveying a wide area covering the NGC 4839 group to search for globular clusters and use them to investigate any connection between the globular clusters and the merger scenario of the NGC 4839 group. We utilized Subaru Hyper Suprime-Cam archival images of two circular fields with diameter ~1.8 deg, covering the Coma core and the NGC 4839 group. We discuss the results with regard to the formation history of the NGC 4839 group.

• Korean Journal of Radiology
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• 제2권3호
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• pp.121-131
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• 2001

Echocardiography and catheterization angiography suffer certain limitations in the evaluation of congenital heart diseases in adults, though these are overcome by MRI, in which a wide field-of view, unlimited multiplanar imaging capability and three-dimensional contrast-enhanced MR angiography techniques are used. In adults, recently introduced fast imaging techniques provide cardiac MR images of sufficient quality and with less artifacts. Ventricular volume, ejection fraction, and vascular flow measurements, including pressure gradients and pulmonary-to-systemic flow ratio, can be calculated or obtained using fast cine MRI, phase-contrast MR flow-velocity mapping, and semiautomatic analysis software. MRI is superior to echocardiography in diagnosing partial anomalous pulmonary venous connection, unroofed coronary sinus, anomalies of the pulmonary arteries, aorta and systemic veins, complex heart diseases, and postsurgical sequelae. Biventricular function is reliably evaluated with cine MRI after repair of tetralogy of Fallot, and Senning's and Mustard's operations. MRI has an important and growing role in the morphologic and functional assessment of congenital heart diseases in adolescents and adults.