• Tunnel and Underground Space
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• v.27 no.1
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• pp.1-11
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• 2017

Most of the local limestone mines are developed as large-opening underground mines, while mine ventilation is heavily dependent on the natural ventilation and auxiliary systems, rather than the mechanical ventilation system using main fans. The current auxiliary ventilation system with fan and ducting requires optimization since enhanced deployment of diesel equipment demands higher airflow rate and the associated cost is expected to be too excessive for the local mine operators. This paper aims at optimizing the fan capacity for the working site ventilation through comparing the fan pressure in the mine airway and the ventilation efficiency of an axial-flow fan and a propeller fan developed in this study.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.3
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• pp.173-181
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• 2003

Purpose : This study was intended to evaluate the positional relationship between the hyoid bone and the mandible in patients with mandibular protrusion after mandibular set-back surgery by means of 3D-CT. Materials and methods : Preoperative(3 weeks before) and postoperative (6 weeks after) 3D-CT & cephalogram were taken on 32 patients(12 male, 20 female, mean age of 23.2) treated by bilateral sagittal split osteotomy with rigid fixation. The angular measurement on 3D-CT basilar view were deviation of Me & H, long axis angle of left & right cornu majus. The lineal measurement on 3D-CT basilar view were composed of intercondylar line and coordinates(x,y) of Me & H. The angular & lineal measurement of lateral cephalogram were composed of mandibular plane angle, SNA, SNB, ANB, FH-NA & FH-NB, and coordinates(x,y) of B, Pog, Me & H, PAS, Lpw, MPH and IAS. On the frontal cephalogram, deviation of Me were evaluated. Results : The mean mandibular set-back was 8.0mm horizontally and mandibular plane angle was slightly increased. The hyoid bone was displaced postero-inferiorly, the distance between MP(mandibular plane) and H(hyoid bone) was increased and the posterior airway space values (PAS, Lpw, IAS) were decreased. The coordinates Me(x,y), H(x,y) and deviation angle Me'& H' were revealed the strong positive correlation. Conclusion : The results revealed that the horizontal, vertical and transverse relationship of the mandibular and the hyoid bone movements were significantly correlated in patients performed mandibular set-back surgery.

• The Korean Journal of Air & Space Law and Policy
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• v.7
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• pp.101-134
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• 1995

Article 3 Paragraph 1 of the Warsaw Convention regulates the requirements of passenger tickets, Article 4 Paragraph 3, the requirements of baggage tickets, Article 8, the requirements of airway bills. In this article the writer has discussed the legal nature of the documents of air carriage, such as air waybills, passenger tickets and baggage checks. Further, the writer has also discussed several issues relating to the use of the documents of air carriage under the Warsaw Convention. Article 3 Paragraph 2, as well as Article 4 Paragraph 4 and 9 provides that the carrier shall not be entitled to avail himself of the provisions of the Convention which evade or limit his liability. In particular, the Montreal Agreement of 1966 provides that the notification on the carrier's liability in passenger ticket should be printed in more than 10 point type size with contrasting ink colors. However, another question is whether the carrier shall not be entitled to avail himself of the liability limit under the Convention in case the type size is below 10 points. The Convention does not specify the type size of certain parts in passenger tickets and only provides that the carrier shall not be entitled to avail himself of liability limit, when a carrier fails to deliver the ticket to passenger. However, since the delivery of passenger tickets is to provide an opportunity for passengers to recognize the liability limit under the Convention and to map out a subsequent measures, the carrier who fails to give this opportunity shall not be entitled to avail himself of the liability limit under the Convention. But some decisions argue that when the notice on the carrier's liability limit is presented in a fine print in a hardly noticeable place, the carrier shall not be entitled to avail himself under the Convention. Meanwhile, most decisions declare that regardless of the type size, the carrier is entitled to avail himself of liability limit of the provisions of the Convention. The reason is that neither the Warsaw Convention nor the Montreal Agreement stipulate that the carrier is deprived from the right to avail himself of liability limit of the provisions of the Convention when violating the notice requirement. In particular, the main objective of the Montreal Agreement is not on the notice of liability limit but on the increase of it. The latest decisons also maintain the same view. This issue seems to have beeen settled on the occasion of Elisa Chan, et al. vs. Korean Airlines Ltd. The U.S. Supreme Court held that the type size of passenger ticket can not be a target of controversy since it is not required by law, after a cautious interpretation of the Warsaw Convention and the Montreal Agreement highlighting the fact that no grounds for that are found both in the Warsaw Convention and the Montreal Agreement. Now the issue of type size can hardly become any grounds for the carrier not to exclude himself from the liability limit. In this regard, any challenge to raise issue on type size seems to be defeated. The same issue can be raised in both airway bills and baggage tickets. But this argument can be raised only to the tranportation where the original Convention is applied. This creates no problem under the Convention revised by the Hague Protocol, because the Hague Protocol does not require any information on weight, bulk, size, and number of cargo or baggage. The problem here is whether the carrier is entitled to avail himself of the liability limit of the provisions of the Convention when no information on number or weight of the consigned packages is available in accordance with Article 4 of the Convention. Currently the majority of decisions show positive stance on this. The carrier is entitled to avail himself of the liability limit of the provisions of the Convention when the requirement of information on number and weight of consigned packages is skipped, because these requirements are too technical and insubstancial. However some decisions declare just the opposite. They hold that the provisions of the Convention Article 4 is clear, and their meaning and effect should be imposed on it literally and that it is neither unjust nor too technical for a carrier to meet the minimum requirement prescribed in the Convention. Up to now, no decisions by the U.S. Supreme Court on this issue is available.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.12
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• pp.1054-1061
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• 2015

Navigation accuracy, integrity, and safety of commercial Unmanned Aerial Vehicle (UAV) is becoming crucial as utilization of UAV in commercial applications is expected to increase. Recently, the concept of Local-Area Differential GNSS (LADGNSS) which can provide navigation accuracy and integrity of UAV was proposed. LADGNSS can provide differential corrections and separation distances for precise and safe operation of the UAV. In order to derive separation distances between UAVs, modeling of Flight Technical Error (FTE) is required. In most cases, FTE for civil aircraft has been assumed to be zero-mean normal distribution. However, this assumption can cause overconservatism especially for UAV, because UAV may use control and navigation equipments in wider performance range and follow more diverse path than standard airway for civil aircraft. In this research, flight experiments were carried out to understand the characteristics of FTE distribution. Also, this paper proposes to use Johnson distribution which can better describe heavy-tailed and skewed FTE data. Futhermore, Kolmogorov-Smirnov and Anderson-Darling tests were conducted to evaluate the goodness of fit of Johnson model.

• The Korean Journal of Air & Space Law and Policy
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• v.12
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• pp.144-177
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• 2000

Our nation have several procedures and law for national airspace management, however those procedures and law not enough to manage airspace. Therefore, I have studied this paper for improving flight safety and for providing economics flight of civcil aircraft and military aircraft, also, for increasing efficiency of airspace through systematic airspace management, additionally, for improving nation defense ability and for preventation our nation damage when occuring airspace problem. Nowaday. in using airspace. two theory which freely use theory and use theory under jurisdiction is opposed by every nation in worldwide. Consequently. we can realize every nation endeavour to increase their jurisdiction airspace. However. our nation is not still prepared to cope with other nation when occuring airspace trouble. because airspace definition is not prescribed on our aviation law. Therefore. several problems which are improved in our airspace management are presented on this paper. The presented matters are as follows. First, The airspace definition is not prescribed on aviation law and responsibility limit of airspace management is ambugious. Second. problem on structure of approach control area and special airspace, Third. problem on airway system. Fourth. civil agency and military agency apply respectively different regulation in establishment of aircraft flight route, To grasp these problems, considered the airspace conception, airspace classfication. legal character of airspace. our nation airspace state and management together with other nation airspace state and management. also compared our nation airspace management with other nation airspace management. And. improvement methods to solve problems which was appeared by comparing and analysis are presented on this paper.

• Tunnel and Underground Space
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• v.22 no.3
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• pp.163-172
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• 2012

As more diesel engines have been employed in underground limestone mines with large cross section, underground space environment is worsened by diesel exhausts and heat flow. This paper aims for the ultimate goal to optimize the work place environment through assuring the optimal required ventilation rate based on the analysis of the airflow, diesel exhaust gas concentrations and the effects of mechanization and deepening working face on temperature and humidity. Due to the insufficient capacity of the main exhaust fan and poor airway management, stagnant airflows were observed at various locations, while the flow direction was reversed instantly with passing diesel equipment and the flow reversal was also made by the seasonal variation of the outside surface weather. During the loading operation, CO concentration measurements were found to be frequently higher than the threshold limit of 50 ppm, and most of the $NO_2$ measurements during drilling and loading operations shows even more serious levels surpassing the permissible limit of 3 ppm. The actual ventilation quantity was considerably less than the required quantity estimated by the mine health and safety law, and this shortage problem was less serious in colder winter showing more effectiveness of the natural ventilation.

• Journal of Yeungnam Medical Science
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• v.6 no.2
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• pp.47-55
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• 1989

High frequency ventilation (HFV) is a new ventilatory technique that uses very small tidal volume(less than the anatomic dead space) and high frequency, and classified 4 distinct types according to frequency and mode of gas delivery. The mechanism of gas transport of high frequency oscillation ventilation(HFOV) is somewhat different to other types of HFV. To evaluate the determinants of $PaCO_2$ in HFOV, a study was done with a HFOV on 9 cats, and the results are : 1) $PaCO_2$ was not correlated with frequency at the constant stroke volume(6 voltage) and bias flow (6L/minutes). 2) $PaCO_2$ was correlated with stroke volume but not with bias flow under the constant frequency(15Hz/min) and bias flow(3 to 6L/min). From above results, the main determinant of $PaCO_2$ on artificial ventilation with HFOV was stroke volume, but further study between flow, the site of delivery to the airway and humidification of bias flow and $CO_2$ elimination is required in future research.

• Child Health Nursing Research
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• v.10 no.2
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• pp.165-172
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• 2004

The main purpose of this study is to examine the concepts appeared on research and provide future research directions in field of child health nursing. 205 studies of the total 318 studies had been analyzed first for the concepts of the client domain and this time 113 studies were analyzed for the practice, the client-nurse and the environmental domain in nursing. The practice domain includes mentalistitic, enactment, knowledge utilization, role related phenomenon, the client-nurse domain includes touch, communication, interaction phenomenon, and the environmental domain includes physical, social, symbolic environment. All were originally published between 1990 and 2000 in Korea. An analysis of concepts for this study was used the metaparadigm framework for nursing proposed by H. S. Kim(2000). 1. 103 studies belonged to the practice domain. Among them, 56(54％) studies used concepts related to enactment phenomenon like education(21.4％), giving information(7.1％), breast feeding(5.4％), caring(5.4％), airway suction(5.4％), nonnutritive sucking(5.4％). 44(43％) studies used concepts related to knowledge utilization like program development and evaluation of smoking, mother-infant interaction, home health nursing, obesity management. And only 3(3％) studies used role related concepts like quality of nursing, direction of health education, contents of child health nursing education. 2. Only 2(0.006％) studies belonged to the client-nurse domain. One concept is empathy in communication phenomenon and the other concept is role conflict in interaction phenomenon. 3. 8(0.02％) studies belonged to the environmental domain. Among them, 3 studies related to physical environment like space, noise and 5 studies related to social environment like social support, home environment. But the concept of symbolic environment was not used. The findings of this study provide the evidence that research related to the client-nurse domain and the environmental domain should be conducted actively to improve the practice of child health nursing. So that the research in field of child health nursing should be dealt with the concepts of four domains to develop knowledge systematically.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.4
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• pp.339-347
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• 2012

There still remains a controversial debate whether facial skeletal morphological differences exist between patients with nasal and mouth breathing habits. The aim of this study is to assess a relationship between over a period of time mouth breathing and facial skeletal morphology by analyzing lateral cephalometric radiographs of patients with nasal or mouth breathing habits. A total of 120 patients with skeletal class I, II, and III, who had undergone orthodontic diagnosis in department of pediatric dentistry - chonbuk national university, were chosen and their lateral cephalometric radiographs were analyzed. These patients were divided into six groups of 20, each with or without mouth breathing habits. The result of this study has not showed noticeable differences in cephalometric measurements between nasal and mouth breathing children of skeletal class I, II, and III (p > 0.05). However, when the groups were divided by age factor, mouth breathers of age 12 and older showed significant differences in cephalometrics such as decreased ramus height, maxillary retrusion, and clockwise pattern of mandible than children under age 12 (p < 0.05). In conclusion, a longer period of mouth-breathing habits in children displayed a greater chance of impaired facial growth.

• Clinical and Experimental Pediatrics
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• v.53 no.2
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• pp.258-261
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• 2010

Lymphangioma is a rare benign congenital tumor of the lymphatic system, which is commonly diagnosed before 2 years of age. In the natronal report, cystic lymphangioma was usually reported as a huge translucent mass located in the head and neck area. It's occurrence in retropharyngeal space with respiratory obstruction and swallowing difficulty in neonate is extremely rare and postoperative nasopharyngeal reflux has rarely been reported. Complete resection is the standard therapy. However, involvement of the upper airway may be determining prognosis in the extensive lymphangiomas because of the difficulty of complete excision. We present a case of cystic lymphangioma in neonate which was initially asymptomatic but gradually progressed to cause respiratory obstruction due to enlargement. After resection, nasopharyngeal reflux developed with dysfunction of the soft palate and gradually improved with conservative care over 5 months.