• Journal of Korean Tunnelling and Underground Space Association
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• v.22 no.2
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• pp.197-217
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• 2020

Shield TBM tunneling, used in the construction of Seoul subway line 7 and line 9, has been well known as a very efficient, as well as safe, tunneling method. Although the Shield TBM method has been known to be effectively used in poor ground conditions, a number of troubles have occurred during the use of the shield TBM, due to inappropriate machine selection, machine breakdown, and unpredicted ground conditions etc. In this study, several accidents and trouble cases occurred during excavation by Shield TBM, reported from Japan, were investigated. A series of numerical analysis was then performed to compare with the trouble cases and back-analysis results for the cause analysis. The lessons learned from the case studies are presented at the end.

• Proceedings of the SCSK Conference
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• 1999.10a
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• pp.132-132
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• 1999

In the cosmetics field, facial skins have been classified into four types according to self estimation as well as physiological parameters. The aim of this study is to understand skin condition in the levels and composition of stratum corneum (SC) lipids, and to propose new classification for skin types. We assessed the relationship between the SC lipid composition and the self-estimated skin types or physiological parameters of the skin. Sensitive skin has been of great concern over the last decades, and it should be recognized as a skin type. Therefore, we also investigated the influence of the SC lipid composition on variations of sensitivity evaluated by the Stinging Test. Fifty-five healthy Japanese women aged 22-44 participated in this study. Skin biopsies were taken from facial skin using polyethylene sheet with cyanoacrylate. SC lipids were extracted and separated into individual lipid classes. The combined ceramides and cholesterol were quantified by HPTLC. Free fatty acid was quantified according to the ACS-ACOD method. Instrumental measurements were made at the site around the biopsy. In addition, the Stinging Test and a sensory evaluation questionnaire were administered to all subjects. The generally recognized O-D skin type classification is dependent on the consumer`s subjective assessment with respect to their skin troubles. The product of hydration state and skin surface lipid level showed a significant correlation with self-estimated skin types. The oily-dry skin type classified according to physiological parameters as well as SC lipid levels should be characterized as delicate skin with its barrier function deteriorating in the winter. Two groups of sensitive skin were established. One is the barrier function of the skin is deteriorated, and another is the sebaceous gland activity is in decline.

• Journal of the Korea Society of Computer and Information
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• v.16 no.7
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• pp.35-47
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• 2011

This paper proposes a set of rules to automatically generate OWL ontologies from relational databases. The purpose of the rules is to allow semantic access to existing RDB data without any database schema transformation and data migration process. In other words, the rules help a RDBMS play as a web ontology repository as well. However, the use of the mapping rules between RDB and OWL proposed by other studies for the objective causes troubles as follows. First, databases including the tables with a specific structure can't be translated into OWL. Second, the process for extracting an OWL individual unnecessarily lead to database join operations, or several SQL queries. On the other hand, our rules is designed to prevent these problems, can generate OWL classes and properties from database schemas and can generate OWL individuals from the database instances. In addition, an ontology generated by our rules is an OWL 2 DL ontology.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.13 no.1
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• pp.88-94
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• 1991

Maxillofacial deformities are not considered to be a trouble in social life but function. So many maxillofacial plastc surgeons has made efforts to overcome these troubles and bring out more positive life. The proper proportion and shape decide esthetic quality. Lower third of face was consist with lip, cheek, mandibular lower border and mandibular angle. Widening lower third of face give a impression with muscular and recklessness. And lower and wide mandibular angle makes face square shape. Unilateral involvement cause asymmestric face. These face is considered unfavorable, especially in Korea or Japan. We prevent a number of with mandibular angle Bulging which was corrected with mandibular osteotomy or masseter myotomy.

• Journal of Digital Convergence
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• v.14 no.7
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• pp.213-223
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• 2016

The research mainly focused on how the nasagastric tube used to solve feeding troubles developed by 30 children with CP(Cerebral Palsy) affects the post-childhood feeding development right after their birth. It tested an articulation skill of the children and surveyed their feeding ability with their care-givers from 1st in July to 30th in August, 2015. This study conducted an investigation of the way a feeding ability affects an articulation skill. It suggested that an articulation accuracy significantly depends on whether or not the nasagastric tube is used. Also, the findings showed that the post-articulation accuracy is quite related with the problems for the liquid intake, the use of special feeding methods and tools, and biting and chewing among the evaluating problems for the childhood feeding ability. The research concluded that some areas in the early childhood feeding ability have an apparent influence on the post-articulation skill for children with CP.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.165-172
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• 2004

LE-7A is the main engine of the H-IIA launch vehicle. Under its development, the nozzle suffered from two troubles during startup and shutdown transients of the engine. One is a large side load, which damages the actuator of the nozzle, and the other is damage on regenerative cooling tubes due to high heat load. It has been considered that these problems are caused by a peculiar separation pattern called Restricted Shock Separation (RSS). RSS is observed in several rocket nozzles, for example, LE-7A nozzle, Vulcain nozzle and so on. Their contours are not conventional truncated perfect (TP) nozzle - LE-7A nozzle is a compressed truncated perfect (CTP) nozzle and Vulcain nozzle is a thrust optimized (TO) nozzle. Although it is believed that the occurrence of RSS is affected by the nozzle contour, the mechanisms are not clarified sufficiently yet. In the present paper, a parametric numerical study is carried out to investigate the mechanisms of the occurrence of RSS in CTP nozzles during startup transient. The results show that RSS is caused by the adverse pressure gradient downstream of the Mach disk. The adverse pressure gradient is caused by the interaction of the pressure wave and Mach disk. The method to avoid the occurrence of RSS is also examined. A small step inside the nozzle affects the position of the separation point and prevents RSS. The result shows that the possibility that RSS can be suppressed by controlling the position of the separation point.

• Journal of Korea Ship Safrty Technology Authority
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• s.22
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• pp.34-53
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• 2007

In the case of hull material. large sized merchant ships are made of steel, on the other hand FRP or wood are used for small sized fishing boats. At present in Korea approximately 88,500 fishing boats are in operation of which 70% are made of FRP In the meantime, stainless steel is frequently used as shaft materials of the small-size FRP fishing boat. Namely, the kinds of shaft materials are STS 304(18Cr-8Ni), STS 316(18Cr-12Ni-2.5Mo steel) and STS 630(17Cr-Ni-Nb steel)etc. Among these things, STS 304 which is the cheapest and having ordinary corrosion resistance is most widely used as 2nd class shaft material. But, using STS 304 for shaft system material of the small-size FRP fishing boat on seawater environments entails a severe corrosion which causes shaft system troubles. Particularly, the corrosions tend to be concentrated of the stern and bow side, propeller shaft surface of inside of stern tube and the boat having no stern cooling pipe line system. As a solution for those problems, research on the ways to mitigate corrosion on the part of 2nd class stainless steel shaft have been undertaken. In the result, not only clarification for the reason of corrosion of the part of stainless steel shaft used mainly for the small-size FRP fishing boat was done, but also most optimal corrosion protection system was developed by experimenting shaft's protection simulation based of the electrochemical cathodic protection principle. In addition, verification through the field test on the optimal cathodic corrosion protection method by means of aluminum sacrificial anode was carried out. In this study, effective and economical shaft's protection system is suggested to the small-size FRP fishing boat operator by substantiating the results obtained from the research on the optimal cathodic protection.

• Korean Journal of Acupuncture
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• v.31 no.4
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• pp.179-187
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• 2014

Objectives : Saam acupuncture initiated by Saamdoin is traditional and originative method, which is characterized by applying the five phases theory and mother-child reinforcement-reduction principle to the selection of acupoints and needling manipulation. Our study was aimed to summarize and assess the use of acupoint SP3(Taebaek) in Saam acupuncture treatment and to further understand Saam acupuncture in an aspect of the combination of acupoints. Methods : We searched the data based on "(Do Hae Kyo Kam) Sa-Ahm's acupuncture method" for SP3 used and acupoint combination including SP3. We performed frequency analysis, network analysis, and cluster analysis for quantitative aspect. To understand clinical implication of SP3 with another acupoint, qualitative and descriptive methods were also carried out. Results and Conclusions : In our study, SP3 was frequently used for tonification of lung, spleen, heart, and kidney meridian and sedation of kidney, heart, and lung meridian. For this, many acupoints such as LU8, LU9, KI3, HT8, KI7, LU10 and LR1 were used with SP3. The combination of SP3 and other acupoints were used to treat stroke, common cold, and pain conditions including headache, low back pain, respiratory disease as well as gastroenteric troubles including stomachache, indigestion, vomiting, and constipation. To further understand Saam acupuncture, an understanding of the five transport points based on five elements characters, pathological changes (deficiency and excess) of viscera and bowels, and concept of source point should be preceded.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.4
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• pp.295-302
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• 2013

In the network coding, throughput can be increased by allowing the transformation of the received data at the intermediate nodes. However, the adversary can obtain more information at the intermediate nodes and make troubles for decoding of transmitted data at the sink nodes by modifying transmitted data at the compromised nodes. In order to resist the adversary activities, various information theoretic or cryptographic secure network coding schemes are proposed. Recently, a secure network coding based on the cryptographic hash function can be used at the random network coding. However, because of the computational resource requirement for cryptographic hash functions, networks with limited computational resources such as sensor nodes have difficulties to use the cryptographic solution. In this paper, we propose a new secure network coding scheme which uses linear transformations and table lookup and safely transmits n-1 packets at the random network coding under the assumption that the adversary can eavesdrop at most n-1 nodes. It is shown that the proposed scheme is an all-or-nothing transform (AONT) and weakly secure network coding in the information theory.

• Journal of the Korean Institute of Gas
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• v.8 no.4 s.25
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• pp.55-61
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• 2004

This paper provided a counter measures against the troubles and accidents that are likely to take place in the power plant using hydrogen gas as a coolant for the cooling system of the generator. Because of the extremely wide flammability limits of hydrogen in comparison to the other flammable gases, the safety measures against the hydrogen accidents is very important to ensure the normal operation of electric-power facility. This study's purpose was a presentation of standard model of safety management of hydrogen equipments in the coal firing power plant such as following items: 1) providing the technical prevention manual of the hydrogen explosions and hydrogen fires occurring in the cooling system of power generator; 2) the selection of explosion-proof equipments in terms of the risk level of operating environment; 3) the establishment of regulations and counter measures, such as the incorporation of gas leakage alarm device, for preventing the accidents from arising, 4) the establishment of safety management system to ensure the normal operation of the power plant.