• Journal of The Geomorphological Association of Korea
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• 제19권1호
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• pp.29-40
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• 2012

The sand dunes at the lower reach of the Duman river indicate that their distribution patterns and directions conform to the dominant northwestern winter wind. On the riverbed of the Duman river at the surroundings of sand dunes form sandy point bars and mid-stream islands. The geomorphic processes of sand dunes can be classified into two types according to the depositional environments via analyses of the sand grain size and stratigraphic profiles. First, the sand dunes of Hoelyongbong, Kyeongshin-Wonjeong, and the riverside areas of the Duman river, have formed by alluvium of the Duman river which deposits and accumulates on the riverbed, then being wind blown to the nearby sand bars, terraces and higher eroded hills. The second type is the active sand dune of the Bangcheon-Nodongja District which develops similarly as to the formation of the first type, but the fixed sand dunes of the district seem to have formed in the underwater condition.

• Journal of the Korea Society for Simulation
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• 제24권3호
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• pp.9-16
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• 2015

This research focuses on analysis of the flight trajectory characteristics of SLBM (Submarine Launched Ballistic Missile) of North Korea. Recently, North Korea tested launching of SLBM which is threatening international security. Also it is known that North Korea had possessed the technologies about SLBM since they disassembled submarines out of commission of the former Soviet Union. If the development of the SLBM of North Korea is completed, it should be affected as asymmetric threat to South Korea. Therefore, for active respondence to these threat, it is essential to analyze the SLBM systematically. In this point of view, this work made a SLBM flight model and simulated. In addition, we controled flight trajectories according to adjusting loft angle and described their characteristics. The sea-based ballistic missile defense system is required for an effective response to the flight trajectory of the SLBM from mid-course to terminal phase.

• Journal of Convergence for Information Technology
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• 제8권4호
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• pp.199-204
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• 2018

This study analyzes Cho, Yong- Pil's contribution on K-Pop history as he celebrates the 50th anniversary of his debut. The history of K-Pop, when Cho has been active in, is divided into three periods. From the late 1960s to the early 1980s was a period when trots and rocks were popular. Soft rock, heavy metal, and ballads came in from the mid-1980s to the early 2000s. From the late 2000s to the present, dance music, mostly hook songs, has dominated. In every inflection point of K-Pop history, he contributed to the development throughout various musical genres. In the first period, he introduced rock music with the unique emotion of Korea by combining the trot and the rock genre. In the second period, he contributed to the development of both rock and ballad genres. In the third period, his hook songs were released to the controversy, but it contributed to creating an atmosphere in which the vocal ability of the vocalist in idol groups was emphasized in the K-pop scene.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제18권11호
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• pp.915-922
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• 2006

Considering heat pipe design principles in fabrication and operational performances, water is one of the most recommended working fluids to make mid to low tempera lure heat pipes. But the conventional water heat pipes might encounter the failure in a cold start-up operation when socked at a chilling temperature lower than the freezing point. If they are subjected to a heat supply for start-up at a temperature around $-20^{\circ}C$, the rate of the vapor flow and the corresponding heat transfer from the evaporator to the condenser is so small that the vapor keeps to stick on the surface of the chilling condenser wall, forming an ice layer, resulting in a liquid deficiency in the evaporator. This kind of problems was resolved by Kang et al. in 2004 by adopting a gas loading heat pipe technology to the conventional water heat pipes. This study was conducted to examine a chilling start-up procedure of gas loading heat pipes by investigating the behaviors of heat pipe wall temperatures. And the thermal resistance of the gas loaded heat pipe that depends on the operating temperatures and heat loads was measured and examined. Two water heat pipes were designed and fabricated for the comparison of performances, one conventional and the other loaded with $N_2$ gas. They were put on start-up test at a heat supply of 30 W after having been socked at an initial temperature around $-20^{\circ}C$. It was observed that the gas loaded one had succeeded in chilling start-up operation.

• Cross-Cultural Studies
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• 제29권
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• pp.177-199
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• 2012

Nowadays migrations between the countries are getting each day more active and a mixture of people with different cultural backgrounds strengthens the hybridism, whereupon the point of view on the migration of Koreans has been changed from a diasporan perspective to an transnational one. The expansion of the transnationalism affects the identity of the subsequent generations of the immigration giving way to a psychologically deterritorialized social identity, which is an important consideration in the study of subsequent generations of the immigration. This study examined the Korean immigration history and the current status of the Korean community in Spain since the 1960s. The early immigrants like fishing vessel crew members, instructors of Taekwondo, chicken sexers who, despite the limits of foreigners in Spain, went to find out the source of life with no hesitation, overcame the difficulties of the early settlers and finally managed to achieve local success. Current history of immigration that began in the mid-1960s went through the maturity during the 1970s and 80s and the Koreans in Spain these days, who have undergone differentiation in the occupational structure because of the crisis of pelagic fisheries, face new challenges due to changes in the environment of the country they reside. The Korean community is regarded as an 'exemplary minority group (Model Minority)' even though it is a minority group in number. Now that the interest for overseas Koreans is higher than ever at home and abroad, due to the economic growth of the Republic of Korea, the spread of its cultural influence -the Korean Wave as proof-, and the overseas Koreans suffrage conducted, the research of the Korean residents in Spain will be important as an advanced research of an unexplored field, as well as an opportunity to broaden the horizons of the existing study area that has mainly dealt with major regions only.

• Steel and Composite Structures
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• 제30권4호
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• pp.393-403
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• 2019

Cold-formed steel (CFS) has a great potential to meet the global challenge of fast-track and durable construction. CFS members undergo large buckling instabilities due to their small wall thickness. CFS beams with corrugated webs have shown great resistance towards web buckling under flexure, when compared to the conventional I-sections. However, the magnitude of global imperfections significantly affects the performance of CFS members. This paper presents the first attempt made to experimentally study the effect of global imperfections on the structural efficiency of various strengthening schemes implemented in CFS beams with corrugated webs. Different strengthening schemes were adopted for two types of beams, one with large global imperfections and the other with small imperfections. Strength and stiffness characteristics of the beams were used to evaluate the structural efficiency of the various strengthening schemes adopted. Six tests were performed with simply supported end conditions, under four-point loading conditions. The load vs. mid-span displacement response, failure loads and modes of failure of the test specimens were investigated. The test results would compensate the lack of experimental data in this area of research and would help in developing numerical models for extensive studies for the development of necessary guidelines on the same. Strengthening schemes assisted in enhancing the member performance significantly, both in terms of strength and stiffness. Hence, providing an economic and time saving solution to such practical structural engineering problems.

• Journal of the Korean Society of Radiology
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• 제13권3호
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• pp.415-424
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• 2019

The purpose of this study would like to investigate the effect of major satisfaction on the career decision commitment for students in department of radiological science. Using the structured questionnaire we perform the self-report survey for 218 students. As a result, the degree of major satisfaction for students is found to be mid-range, and the degree of career decision commitment for ones is lowest in the first graders and the highest in the fourth graders. A notable point is that the degree of major satisfaction seems to have a significant influence on career decision commitment. Especially, it was found that major of pride is the most influential factor in career decision commitment. From this study, finally, it seems that a method to improve the career decision commitment is needed because the degree of career decision commitment of students is assessed to be fairly lowered at a level of non-commitment.

• Journal of Radiation Protection and Research
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• 제44권1호
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• pp.32-42
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• 2019

Background: There have been much efforts to develop the proper and realistic machine Quality Assurance (QA) reflecting on real Volumetric Modulated Arc Therapy (VMAT) plan. In this work we propose and test a special VMAT plan of plan-class specific (pcsr) QA, as a machine QA so that it might be a good solution to supplement weak point of present machine QA to make it more realistic for VMAT treatment. Materials and Methods: We divided human body into 5 treatment sites: brain, head and neck, chest, abdomen, and pelvis. One plan for each treatment site was selected from real VMAT cases and contours were mapped into the computational human phantom where the same plan as real VMAT plan was created and called plan-class specific reference (pcsr) QA plan. We delivered this pcsr QA plan on a daily basis over the full research period and tracked how much MLC movement and dosimetric error occurred in regular delivery. Several real patients under treatments were also tracked to test the usefulness of pcsr QA through comparisons between them. We used dynalog file viewer (DFV) and Dynalog file to analyze position and speed of individual MLC leaf. The gamma pass rate from portal dosimetry for different gamma criteria was analyzed to evaluate analyze dosimetric accuracy. Results and Discussion: The maxRMS of MLC position error for all plans were all within the tolerance limit of < 0.35 cm and the positional variation of maxPEs for both pcsr and real plans were observed very stable over the research session. Daily variations of maxRMS of MLC speed error and gamma pass rate for real VMAT plans were observed very comparable to those in their pcsr plans in good acceptable fluctuation. Conclusion: We believe that the newly proposed pcsr QA would be useful and helpful to predict the mid-term quality of real VMAT treatment delivery.

• The Bulletin of The Korean Astronomical Society
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• 제43권2호
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• pp.48.4-49
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• 2018

We studyed an Korean astrolabe made by Ryu Geum (1741~1788), the late Joseon Confucian scholar. It has a diameter of 17 cm and a thickness of 6 mm and is now owned by Museum of Silhak. In the 1267 of the reign of Kublai Khan of Mogol Empire, Jamal al Din, an Ilkhanate astronomer, present an astrolabe to his emperor together with 6 astronomical instruments. In 1525, an astrolabe was first made in Korea by Lee, Sun (李純, ?~?), a Korean astronomer and royal official of Joseon Dynasty. He was referred to Gexiang xinshu, a Mongloian-Chinese book by Zhao, Youqin (1280-1345), an astronomer of Mongolian Empire. This astrolabe has not been left. In the mid-17th century, an astrolabe was introduced to Joseon again through Hungai tongxian tushuo (渾蓋 通憲圖設) edited by Chinese Mathematician Li Zhi-zao (李之藻, 1565~1630), that originated from Astrolabium (1593) of Christoph Clavius (1538-1612). It seems that Ryu refered to Hungai tongxian tushuo which affect to Hongae-tongheon-ui (渾蓋通憲儀) edited by Nam, Byeong-Cheol (南秉哲, 1817~1863). We analysis lots of circles on the mother and a set of index from the rete of of Ryu's astrolabe. We find that the accuracy of circles has about 0.2~0.4 mm in average if the latitude of this astrolabe is 38 degrees. 11 indices of the rete point bright stars of the northern and southern celestial hemisphere. Their tip's accuracies are about $2^{\circ}.9{\pm}3^{\circ}.2$ and $2^{\circ}.3{\pm}2^{\circ}.8$ on right ascension and declination of stars respectively.

• Journal of the Architectural Institute of Korea Planning & Design
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• 제35권11호
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• pp.89-100
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• 2019

In modern Korean architecture, some of school buildings have been referred to as Tudor Gothic style by its design elements. But, to be more exact in detail, they have to be interpreted as a Collegiate Gothic style that has occurred in the United States since the mid-19th century. Therefore, this study explains the progress of Collegiate Gothic style in the United States through the literature published since the 19th century, and examines the adoptation process of Korea. In addition, this thesis analyzes the characteristics of American Collegiate Gothic style and the elements of Collegiate Gothic style universally adopted in Korea, and then attempts a new interpretation on the representative Collegiate Gothic architecture in Korea. The results of this research are as follows. The Collegiate Gothic style in the United States caused by the change of educational environment in the 19th century was accepted for religious purposes by foreign architects such as Henry K. Murphy and W. Vories, and was also accepted by domestic architects who were directly influenced by Western architecture such as Park, Dong-jin. In addition, the accepted Collegiate Gothic style shows common features not only in the decoration of Tudor Gothic but also in the material and compositional aspects such as the quadrangle plans and the rock-faced exterior facades. From the point of view of the Collegiate Gothic style then in vogue at many schools and universities, further researches will be needed to interpret modern school architectures in Korea.