• 대한안전경영과학회지
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• 제11권1호
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• pp.1-6
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• 2009

The specific feature of trains as a means of transportation is that, on one side, at once they can carry big loads but, at the same time, if an accident occurs, it potentially leads to many human casualties or big material losses. Especially, train accidents caused by bad weather conditions result in many fatal losses of human lives and property. In Korea many railways run either in mountainous areas or along rivers thus making them especially susceptible to natural hazards. The types of damages inflicted by heavy rains resulting from rapidly changing meteorological conditions are diverse; and not only their scope is big but also they repeat regularly. Consequently, this study analyses the reasons why such effects of heavy rains on the railway conditions, damage to the railways caused by heavy rains or cases of stone fall as well as other types of accidents are not avoided. Study also, on the basis of laws related to movement in poor weather conditions and specifics of train braking, identifies systematic and technical problems and suggests and emphasizes new complex measures on their prevention.

• 대한치과교정학회지
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• 제12권1호
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• pp.61-68
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• 1982

Tooth Positioner는 band를 제거한 후 가능한 빨리 장착시켜야 susceptible하며 무엇보다도 환자의 생리학적 jaw movement를 설정해서 제작해야 하고 적어도 hingeaxis relation은 찾아서 제작해야한다. Positioner의 장착시간은 하루에 $3\~4$시간의 active biting exercise와 수안시간동안 사용하게 한다. 처음 장착시에 가장 tight하고 이 tightness 는 치아가 요망되는 위치로 근접함에 따라서 점차 감소되고 이 tightness의 감소가 작용효과의 가장 좋은 지침이 되며 자는 하루 하루 그 변화를 느껴야 한다. Positioner가 느슨하게 적합되고 좋은 교합관계를 보이면 장착을 수안시간동안으로 제한시키거나 혹은 깨어 있을 동안 한 두시간 장착하게 한아. 대개 $3\~4$주 후에 predetermined pattern과 유사하게 되며, 일반적으로 장착 후 $8\~10$주 후에 더 장착할 것인가를 결정하고 필요성이 없다면 conventional retainer로 바꾸어 준다. Tooth Positioner는 기능적인 구호흡, thumb sucking, snoring을 해소시켜 줄 수 있으며 jaw relationship이나 overbite문제를 해결할 수 있다. 그리고 chair time을 감소시켜 줄 수 있으며 tissue tone을 자극해서 치아위치를 증진시키는데 끊임없이 작용한다. 그러나 제작에 많은 시간이 걸리고 치아를 배열하는 술자의 능력에 따라 치료효과가 많이 좌우되며 너무 bulky하므로 이물감이 커서 유용하게 장착할 수 있는 시간이 제한적이고 natural muscle balance에 대해 간헐적인 교정력을 가함으로써 치아를 loosening 시킬 수 있다. 이 장치물은 다른 removable appliance와 같이 환자의 협조가 무엇보다 중요하므로 환자에게 장착동기를 유발시켜 주는 것이 좋으며 True Blocked Nasal Airway가 있는 환자에게는 금기증이 된다.

• 대한치과의사협회지
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• 제55권3호
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• pp.249-256
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• 2017

Gingival recession is one of the common mucogingival problems during the orthodontic treatment. The causes of the gingival recession are similar to gingival recession in patients with periodontal diseases. Accumulation of bacterial deposits around the natural teeth induces the gingival inflammation and gingival recession occurs in the teeth with the lack of the supporting bone. However, malpositioned teeth which are labially positioned teeth or rotated teeth are more risky for gingival recession. Once root is exposed to oral cavity due to gingival recession, the orthodontic tooth movement is compromised and esthetic problems appeared. In addition, excessive gingival recession over the mucogingival junction jeopardizes the oral hygiene control, which has a risk of further gingival recession and bone loss around the tooth. To cover exposed root or to prevent further gingival recession, mucogingival surgery with gingival graft is recommended for the patients under orthodontic treatment. This case report aimed to present the mucogingival treatments of gingival recession observed during orthodontic treatment. Case I had had initial slight gingival recession before the orthodontic treatment. However, during the retraction phases, the gingival recession progressed and the periodontal treatment was referred. In case II, miller Class III gingival recession was occurred after correction of rotation. Both cases were treated by coronally advanced flap with free gingival grafts and recovered to the level of adjacent teeth despite of complete root coverage was not achieved in Case II. After periodontal treatment, orthodontic treatment was successfully completed. In conclusion, mucogingival surgery during the orthodontic treatment is recommended for the successful orthodontic treatment as well as periodontal health.

• 한국실내디자인학회논문집
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• 제27호
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• pp.145-151
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• 2001

There is so much difference in the way we perceive nature whether from eastern or western, present or past standpoint. however, awareness of coexistence between human beings and nature along with the concept that the most natural is th e most beautiful remain unchanged. The desire to describe the beauty of nature have existed all through the ages, but the (new) naturalism movement was spawned in our time when so much devastation and side effects took place for the expediency of nature, and field of display has been trying new interpretation of nature with direct or applied method. Naturalism trend is studied using the categories such as relationship between human and nature, space concept in western and eastern society, and the definition of view of nature in modern time. Elements of naturalism display are classified into the element of physical properties and element beyond the physical properties, and then methodology on naturalism display is investigated, using the illustration of display examples, in order to know the most essential elements of display, which are the physical properties such as space, light, object, glass, are expressed based on the elemental concept like nature, an accident, dynamic state, variability. As mentioned above, Naturalism display consists of physical properties and phenomenon. How to ive strong impression to a spectator depends on the ability to create effective space applying these elements. The significance of this study comes to surface in a time when the tremendous emphasis is put on the importance of nature and concerns about the role of display has become even greater.

• 한국항해학회지
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• 제15권3호
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• pp.1-11
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• 1991

As increasing needs of marine transportation , world merchant fleet and ship's size were enlarged and it caused frequent disasters in human lives and natural environment. By the reason of the above, they started to establish the Vessel Traffic System (VTS) at the European coast in 1960' and most of advanced contries established and managed it to prevent the sea traffic accidents in these days. The concept of traffic control at sea can be divided into three types. First, the initial gathering of informations about ship's identity and movement etc.. Second, monitoring of the traffic flow and amendment of instructions. Third , organization and direction of ships by allocating routes and speeds. Where the goal of traffic control is safety of traffics and developing effectiveness of navigation channel, if traffic volume is less tan channel capacity then the above first or second level of control would be sufficient but if it is bigger than that , more positive policy of control should be adopted as same as third type of the above. In this paper where the strategy of VTS is focused on the control of traffic density to be spread equality, as possible , all over the navigation channels and also improvement of effectiveness , it suggests algorithm to assign the vessels to the channels with balanced traffic density , and other algorithms using D.P. to sequence the vessels assigned to one channel in optimum order which decreases the mean waiting time in sense of channel effectiveness with numerical examples.

• 한국조경학회지
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• 제34권1호
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• pp.10-20
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• 2006

This study is to introduce the improvement and management of Ecoduct located in Uiwang's Mt. Obong, Gyeonggi province. The inner planting of Ecoduct is not very related to the flora of mountain areas nearby. The difference in the index of plant crown volume(GVZ), the similarity index(S.I.), and monitored animals is significant between Ecoduct and mountain areas. Putting together all of the results, the initial selection of movement and target species is excessive in number. Target species must be selected again. They will be species that are currently found on the site. The Ecoduct space must be divided into two parts: buffer planting space and wildlife corridor. Reforestation is needed since the GVZ is remarkably lower in Ecoduct than in the nearby mountain areas. Besides the vegetation of Ecoduct is densely planted in guidance planting space to connect the southern Quercus mongolica community and the northern Quercus acutissima community. Proper upkeep after construction should be continuously conducted to maintain the procedure of natural change.

• 한국지형학회지
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• 제24권2호
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• pp.1-13
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• 2017

Massive coastal sand dunes are distributed in Ui-island, Shinan-gun. The sand dunes in Ui-island is worth studying, in terms of preserving natural environment without anthropogenic impacts. In this study, we surveyed geomorphological processes of the sand dune based upon measuring of geometric properties, grain size analysis, and OSL(Optically Stimulated Luminescence) age dating. The sediments of the dune consist mainly of well sorted medium sand with about 250$\mu$m. Based on spatial distribution of sand dunes, we found that they are formed by northwest monsoon during winter, and sands are supplied from Seongchon area in northern UI-island. According to OSL age dating, the sand dunes were deposited from $0.07{\pm}0.01ka$ to $0.17{\pm}0.04ka$. This result shows that the transformation of the dune due to the sand movement by wind was active during the last 100-200 years. The aerial photograph indicates that the dimension of the largest sand dune has decreased since 1945. Further research is needed to get more detailed information on geomorphic changes of sand dunes in UI-island.

• 대한조선학회논문집
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• 제31권2호
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• pp.65-77
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• 1994

본 논문은 SWATH선의 히브 및 피치 제어에 대한 LQ이론의 상세한 응용과정을 제시한다. 부가질량과 감쇄계수를 상하동요 고유주기에서의 값으로 근사함으로써 선형 시불변 2차 연립 미분방정식이 주파수 응답 모델로부터 유도된다. 파기진력은 사인파들의 합으로서 모델링 된다. 좋은 과도응답(transient response)과 적절한 제어핀 운동을 얻기 위하여 상태 및 제어 가중행렬의 체계적인 선택과정이 제시된다. 본 논문의 제어기 설계과정의 타당성이 시간영역 및 주파수 영역에서의 시뮬레이션과 전달함수행렬의 특이값 선도에 의해 철저히 조사되어 진다. 최종 설계된 제어시스템은 본 연구의 응용이 성공적이었음을 나타내는 좋은 전체 성능을 보여준다.

• 통합자연과학논문집
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• 제9권1호
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• pp.67-71
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• 2016

The university president direct election system in Korea had begun in 1987 as a movement of college democratization in the 1980s after 6.29 Declaration. Since then, many national/private universities had adopted the election system. However, it has posed many problems and it caused a sharp division of opinions between those who approve and disapprove the direct election system. Since 2005, the government has made official of the reformation and/or abolition of the university president direct election system, and has kept pushing for universities to give up the direct election system. Now, only 3 or 4 universities hold on to the system, and many universities have changed into the indirect election system. In the indirect election, a key is the composition of president nomination committee, which confirms the university members's variety. Many universities adopting the indirect election system have used simple random sampling, like drawing lots, to compose the president nomination committee. However, drawing lots has a problem that it has large possibility of composing a biased committee. This research suggests systematic sampling as an alternative to drawing lots. A numerical analysis was conducted using a data of a university in which the indirect election was implemented recently. The drawing lots gave the biased nomination committee. On the other hand, the systematic sample improves the problem and confirms more the variety of all members.

• 통합자연과학논문집
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• 제14권3호
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• pp.107-115
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• 2021

The demand for traceability of meat and livestock supply chains is growing due to the high-profile incidents of hormonal contamination. E. coli, dioxin, BSE, and antibiotics have been recorded. In this paper, we present blockchain-based poultry information management system design and implementation using Hyperledger Fabric. The proposed system offers accurate, decentralized, immutable and consensus process that promote trust and transparency between stakeholders. The main tasks of the system include the recording of the information associated with poultry rearing (from a hatchery to a farm), status report of the farm activities on a monthly basis. The system can track movement of docks through the supply chain until delivery to the final consumer through the retail outlet. The ability to trace the source of livestock product through all the stages of rearing/production, processing and distribution is essential for ensuring food safety as recall of contaminated product can easily be done thereby increasing consumer confidence.