• Title/Summary/Keyword: Free Space Method

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Experimental and CFD Study on the Exhaust Efficiency of a Smoke Control Fan in Blind Entry Development Sites (맹갱도 굴진 작업공간내 방재팬의 화재연 배기효율에 관한 현장실험 및 CFD 연구)

  • Nguyen, Vanduc;Kim, Dooyoung;Hur, Wonho;Lee, Changwoo
    • Tunnel and Underground Space
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    • v.28 no.1
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    • pp.38-58
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    • 2018
  • The ventilation system plays a crucial role in underground mine safety. The main objective of the ventilation system is to supply sufficient air to dilute the contaminated air at working places and consequently provide tenable environment during the normal operation, while it also should be capable of controlling the fire propagation and facilitate rescue conditions in case of fire in mines. In this study, a smoke control fan was developed for the auxiliary ventilation as well as the fire smoke exhaust. It works as a free-standing auxiliary fan without tubing to dilute or exhaust the contaminated air from the working places. At the same time, it can be employed to extract the fire smoke. This paper aims to examine the smoke control efficiency of the fan when combined with the current ventilation system in mines. A series of the site experiments and numerical simulations were made to evaluate the fan performance in blind entry development sites. The tracer gas method with SF6 was applied to investigate the contaminant behavior at the study sites. The results of the site study at a large-opening limestone mine were compared with the CFD analysis results with respect to the airflow pattern and the gas concentration. This study shows that in blind development entry, the most polluted and risky place, the smoke fan can exhaust toxic gases or fire smoke effectively if it is properly combined with an additional common auxiliary fan. The venturi effect for smoke exhaust from the blind entry was also observed by the numerical analysis. The overall smoke control efficiency was found to be dependent on the fan location and operating method.

Analysis of the Current Situation and Improvement Method of Correctional Facility Libraries in Korea (한국의 교도소도서관 현황분석과 개선방안)

  • Kwon, Se-Hee;Yoon, Hye-Young
    • Journal of Information Management
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    • v.40 no.3
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    • pp.125-150
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    • 2009
  • This study aims to investigate current situation and improvement method of correctional facility libraries in Korea. Thus this study made the following suggestions to improve the operation of correctional facility library and to facilitate its growth so that the inmates' basic right to know and access information could be guaranteed: First, there should institutional and legal grounds for the establishment and operation of correctional facility library such as standards, guidelines, and enactments; second, the government should provide enough budgets for human and material resources so that a prison library can equip itself with materials, facilities, and staff to run smoothly; third, the inmates' free access to the library service should be guaranteed in an open space; fourth, the library should introduce an automation system for lending, returning, and handling materials; fifth, a collaboration system with external resources should be set up to make effective use of lacking resources; sixth, programs should be researched and developed to analyze the size and composition of the inmates, the needs of the inmates, and available service; and finally, there should be staff with the qualification of a librarian to be responsible for the operation and management of a correctional facility library and to offer specialized library service to the inmates.

Development of the Seepage Flow Monitoring Method by the Hydraulic Head Loss Rate (수두손실률에 의한 침투류 감시기법 개발)

  • Eam, Sung-Hoon;Kang, Byung-Yoon;Kim, Ki-Wan;Koo, Ja-Ho;Kang, Shin-Ik;Cha, Hung-Youn;Jung, Jae-Hyun;Cho, Jun-Ho;Kim, Ki-Soo
    • Journal of the Korean Geotechnical Society
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    • v.26 no.5
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    • pp.37-48
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    • 2010
  • In this study, the seepage flow monitoring method by the hydraulic head loss rate was developed for the purpose of application to offshore construction site enclosed by cofferdams in which seepage force varies periodically. The amount of the hydraulic head loss rate newly defined in this graph was in a range between 0 and 1. The zero of the rate means the existence of flow with no seepage resistance. The 1 of the rate means no seepage flow through the ground. The closer to 1 the coefficient of determinant in the hydraulic head loss graph is, the more the ground through which seepage water flows is stable. The closer to 0 the coefficient of determinant in the hydraulic head loss graph is, the more the ground through which seepage water flows was unstable and the higher the possibilities of existence of empty space or of occurrence of piping on the seepage flow pass in the ground is. The hydraulic head loss graph makes it possible to monitor sensitively the situation of seepage flow state, and the graph helps to understand easily the seepage flow state at the specific section on the whole cofferdam.

Integrity evaluation of grouting in umbrella arch methods by using guided ultrasonic waves (유도초음파를 이용한 강관보강다단 그라우팅의 건전도 평가)

  • Hong, Young-Ho;Yu, Jung-Doung;Byun, Yong-Hoon;Jang, Hyun-Ick;You, Byung-Chul;Lee, Jong-Sub
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.15 no.3
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    • pp.187-199
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    • 2013
  • Umbrella arch method (UAM) used for improving the stability of the tunnel ground condition has been widely applied in the tunnel construction projects due to the advantage of obtaining both reinforcement and waterproof. The purpose of this study is to develop the evaluation technique of the integrity of bore-hole in UAM by using a non-destructive test and to evaluate the possibility of being applied to the field. In order to investigate the variations of frequency depending on grouted length, the specimens with different grouted ratios are made in the two constraint conditions (free boundary condition and embedded condition). The hammer impact reflection method in which excitation and reception occur simultaneously at the head of pipe was used. The guided waves generated by hitting a pipe with a hammer were reflected at the tip and returned to the head, and the signals were received by an acoustic emission (AE) sensor installed at the head. For the laboratory experiments, the specimens were prepared with different grouted ratios (25 %, 50 %, 75 %, 100 %). In addition, field tests were performed for the application of the evaluation technique. Fast Fourier transform and wavelet transform were applied to analyze the measured waves. The experimental studies show that grouted ratio has little effects on the velocities of guided waves. Main frequencies of reflected waves tend to decrease with an increase in the grouted length in the time-frequency domain. This study suggests that the non-destructive tests using guided ultrasonic waves be effective to evaluate the bore-hole integrity of the UAM in the field.

The Current Status of the Warsaw Convention and Subsequent Protocols in Leading Asian Countries (아시아 주요국가(主要國家)들에 있어서의 바르샤바 체제(體制)의 적용실태(適用實態)와 전망(展望))

  • Lee, Tae-Hee
    • The Korean Journal of Air & Space Law and Policy
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    • v.1
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    • pp.147-162
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    • 1989
  • The current status of the application and interpretation of the Warsaw Convention and its subsequent Protocols in Asian countries is in its fredgling stages compared to the developed countries of Europe and North America, and there is thus little published information about the various Asian governments' treatment and courts' views of the Warsaw System. Due to that limitation, the accent of this paper will be on Korea and Japan. As one will be aware, the so-called 'Warsaw System' is made up of the Warsaw Convention of 1929, the Hague Protocol of 1955, the Guadalajara Convention of 1961, the Guatemala City Protocol of 1971 and the Montreal Additional Protocols Nos. 1,2,3 and 4 of 1975. Among these instruments, most of the countries in Asia are parties to both the Warsaw Convention and the Hague Protocol. However, the Republic of Korea and Mongolia are parties only to the Hague Protocol, while Burma, Indonesia and Sri Lanka are parties only to the Warsaw Convention. Thailand and Taiwan are not parties only to the convention or protocol. Among Asian states, Indonesia, the Phillipines and Pakistan are also parties to the Guadalajara Convention, but no country in Asia has signed the Guatemala City Protocol of 1971 or the Montreal Additional Protocols, which Protocols have not yet been put into force. The People's Republic of China has declared that the Warsaw Convention shall apply to the entire Chinese territory, including Taiwan. 'The application of the Warsaw Convention to one-way air carriage between a state which is a party only to the Warsaw Convention and a state which is a party only to the Hague Protocol' is of particular importance in Korea as it is a signatory only to the Hague Protocol, but it is involved in a great deal of air transportation to and from the united states, which in turn is a party only to the Warsaw Convention. The opinion of the Supreme Court of Korea appears to be, that parties to the Warsaw Convention were intended to be parties to the Hague Protocol, whether they actually signed it or not. The effect of this decision is that in Korea the United States and Korea will be considered by the courts to be in a treaty relationship, though neither State is a signatory to the same instrument as the other State. The first wrongful death claim in Korea related to international carriage by air under the Convention was made in Hyun-Mo Bang, et al v. Korean Air Lines Co., Ltd. case. In this case, the plaintiffs claimed for damages based upon breach of contract as well as upon tort under the Korean Civil Code. The issue in the case was whether the time limitation provisions of the Convention should be applicable to a claim based in tort as well as to a claim based in contract. The Appellate Court ruled on 29 August 1983 that 'however founded' in Article 24(1) of the Convention should be construed to mean that the Convention should be applicable to the claim regardless of whether the cause of action was based in tort or breach of contract, and that the plaintiffs' rights to damages had therefore extinguished because of the time limitation as set forth in Article 29(1) of the Convention. The difficult and often debated question of what exactly is meant by the words 'such default equivalent to wilful misconduct' in Article 25(1) of the Warsaw Convention, has also been litigated. The Supreme Court of Japan dealt with this issue in the Suzuki Shinjuten Co. v. Northwest Airlines Inc. case. The Supreme Court upheld the Appellate Court's ruling, and decided that 'such default equivalent to wilful misconduct' under Article 25(1) of the Convention was within the meaning of 'gross negligence' under the Japanese Commercial Code. The issue of the convention of the 'franc' into national currencies as provided in Article 22 of the Warsaw Convention as amended by the Hague Protocol has been raised in a court case in Korea, which is now before the District Court of Seoul. In this case, the plaintiff argues that the gold franc equivalent must be converted in Korean Won in accordance with the free market price of gold in Korea, as Korea has not enacted any law, order or regulation prescribing the proper method of calculating the equivalent in its national currency. while it is unclear if the court will accept this position, the last official price of gold of the United States as in the famous Franklin Mint case, Special Drawing Right(SDR) or the current French franc, Korean Air Lines has argued in favor of the last official price of gold of the United States by which the air lines converted such francs into us Dollars in their General Conditions of Carriage. It is my understanding that in India, an appellate court adopted the free market price valuation. There is a report as well saying that if a lawsuit concerning this issue were brought in Pakistan, the free market cost of gold would be applied there too. Speaking specifically about the future of the Warsaw System in Asia though I have been informed that Thailand is actively considering acceding to the Warsaw Convention, the attitudes of most Asian countries' governments towards the Warsaw System are still wnot ell known. There is little evidence that Asian countries are moving to deal concretely with the conversion of the franc into their own local currencies. So too it cannot be said that they are on the move to adhere to the Montreal Additional Protocols Nos. 3 & 4 which attempt to basically solve many of the current problems with the Warsaw System, by adopting the SDR as the unit of currency, by establishing the carrier's absolute liability and an unbreakable limit and by increasing the carrier's passenger limit of liability to SDR 100,000, as well as permiting the domestic introduction of supplemental compensation. To summarize my own sentiments regarding the future, I would say that given the fact that Asian air lines are now world leaders both in overall size and rate of growth, and the fact that both Asian individuals and governments are becoming more and more reliant on the global civil aviation networks as their economies become ever stronger, I am hopeful that Asian nations will henceforth play a bigger role in ensuring the orderly and hasty development of a workable unified system of rules governing international commercial air carriage.

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An Evaluation of Outdoor Living Environments for Senior Citizens - Focused on the Prospective Seniors and Senior Citizens in Daejeon - (고령자를 위한 거주지 외부환경 평가 - 대전시 거주 준고령자 이상을 대상으로 -)

  • Lee, Shi-Young;Lee, Hei-Jung;Lim, Byung-Ho;Shim, Joon-Young
    • Journal of the Korean Institute of Landscape Architecture
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    • v.39 no.4
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    • pp.39-48
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    • 2011
  • Korea is rapidly becoming an aging society. This study aims to examine the existing conditions of outdoor living environments to assist a healthy lifestyle for senior citizens and to determine the most influential factor in a senior-friendly outdoor space as well as to suggest improvements in existing conditions focused on the prospective senior population. This study relied on two methods: a descriptive method of researching publications and related scholastic writings and an empirical study that included a survey of present conditions and interviews with the prospective seniors and senior citizens in Daejeon. Conditions of outdoor living environments for seniors were found to be more than adequate in general. But some factors evaluated as low must be carefully tailored for seniors. First, the study showed that seniors evaluated as highest the 'use of a walkway' for a stroll and stayed outside for 1~2 hours at a time. Many vehicles parked in walkways were the most inconvenient factors in going for a walk. Second, the study showed that the evaluation of outdoor space was about average and 'sociality' was evaluated as the lowest. Third, the study showed that men evaluated lower than women 4 items: 'use and convenience of a wheelchair', 'night lighting', 'discrimination of signage at nighttime' and 'trees'. Respondents above the age of 66 are more uncomfortable with items such as 'slippery walking surface', 'stair handrail', 'discrimination of signage at nighttime' and 'direction of apartment complex' while respondents above the age of 80 are more uncomfortable with items of 'slippery walking surface', 'stair handrail' and 'discrimination of signage at nighttime'. Fourth, the evaluation by existing housing patterns was statistically significant in 20 of 22 evaluated items. This means that residents in apartment complex evaluated as high these items in general. In this study, existing outdoor living environments for the elderly did not display any immediately serious issues in the overall evaluation items. Assuming, however, that the aging population will quickly increase in the next ten years, items which are evaluated as low in descriptive statistics and items which give inconvenience to the elderly above the age of 80 in particular will need to be the first areas to be improved.

Surgical Technique for Korean Artificial Heart(AnyHeart) Implantation Using a Right Thoracotomy Approach (우측 개흉술을 이용한 한국형 인공심장(AnyHeart)의 이식기법)

  • Son. Ho-Sung;Sun, Kyung;Shin, Jae-Seung;Lee, Sung-Ho;Jung, Jae-Seung;Lee, Hye-Won;Kim, Kwang-Taik;Kim, Seung-Chul;Won, Yong-Soon;Min, Byoung-Goo;Kim, Hyoung-Mook
    • Journal of Chest Surgery
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    • v.35 no.5
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    • pp.329-335
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    • 2002
  • Background: The surgical technique for biventricular assist device(BVAD) implantation has mainly consisted of cannulation procedures. A median sternotomy has been the technique of choice as it gives a surgeon an excellent exposure of the heart. However, considering that most patients require a future sternotomy or already have a previous sternotomy, sternotomy-related complication remains a major concern in BVAD implantation. Based on this consideration as well as the clinical experiences of conventional heart surgery, the authors have hypothesized that the cardiac chambers for BVAD cannulation can be approached from the right side of the heart. The purpose of this studs to develop a novel surgical technique of right thoracotomy for BVAD implantation in an animals study. Material and Method: For last two years, 16 (11 calves, 3 canines, and 2 sheep) out of 30 experimental animals with AnyHeart implantation underwent a right thoracotomy. The device was used as an implantable BVAD in 14 animals, a wearable BVAD in 1, and an implantable LVAD in 1. The chest cavity was entered through the 4th intercostal space or the 5th periosteal bed. As for the BVAD use, a right inflow cannula was inserted into the right atrial free wall and a right outflow cannula was grafted onto the main pulmonary artery. A left inflow cannula was inserted into the interatrial groove and a left outflow cannula was grafted on the innominate artery of the ascending aorta. The connecting tubes were brought out through the thoracotomy wound and connected to the pump located in the subcutaneous pocket at the right flank. Result: Except for the 5 animals for a lilting test or during the early learning curve, all recovered smoothly from the procedures. The inflow drainage allowed the pump output 6.5 L/min at the maximum with 3-3.5 L/min in an average. Of the survivors, there noted no procedure-related mortality or morbidity. Necropsy findings demonstrated the well-positioned cannula tips in the each cardiac chamber

A Comparative Study of Korean Home Economic Curriculum and American Practical Problem Focused Family & Consumer Sciences Curricula (우리나라 가정과 교육과정과 미국의 실천적 문제 중심 교육과정과의 비교고찰)

  • Kim, Hyun-Sook;Yoo, Tae-Myung
    • Journal of Korean Home Economics Education Association
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    • v.19 no.4
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    • pp.91-117
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    • 2007
  • This study was to compare the contents and practical problems addressed, the process of teaching-learning method, and evaluation method of Korean Home Economics curriculum and of the Oregon and Ohio's Practical Problem Focused Family & Consumer Sciences Curricula. The results are as follows. First, contents of Korean curriculum are organized by major sub-concepts of Home Economics academic discipline whereas curricular of both Oregon and Ohio states are organized by practical problems. Oregon uses the practical problems which integrate multi-subjects and Ohio uses ones which are good for the contents of the module by integrating concerns or interests which are lower or detailed level (related interests). Since it differentiates interest and module and used them based on the basic concept of Family and Consumer Science, Ohio's approach could be easier for Korean teachers and students to adopt. Second, the teaching-learning process in Korean home economics classroom is mostly teacher-centered which hinders students to develop higher order thinking skills. It is recommended to use student-centered learning activities. State of Oregon and Ohio's teaching-learning process brings up the ability of problem-solving by letting students clearly analyze practical problems proposed, solve problems by themselves through group discussions and various activities, and apply what they learn to other problems. Third, Korean evaluation system is heavily rely on summative evaluation such as written tests. It is highly recommended to facilitate various performance assessment tools. Since state of Oregon and Ohio both use practical problems, they evaluate students mainly based on their activity rather than written tests. The tools for evaluation include project documents, reports of learning activity, self-evaluation, evaluation of discussion activity, peer evaluation in a group for each students for their performance, assessment about module, and written tests as well.

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A Comparative Study on the Change in Oriental Linked pearls Pattern (동전(東傳) 연주문의 변천과정 비교연구 -5세기~10세기 벽화복식 및 출토 직물을 중심으로-)

  • An, Bo-yeon
    • Korean Journal of Heritage: History & Science
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    • v.40
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    • pp.243-270
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    • 2007
  • Linked pearls pattern expressed on textiles have no limited scale or shape when manufacturing, so they are free in expression. And from the design, material, and color we can analogize the social culture of that age. Oriental linked pearls pattern was started from the Sasanian Persia and introduced through the Silk Road, so it is closely connected with the East and the West culture. This study will consider from the 5th century to the 10th century; the mural costume of the West Central Asia, the ancient textiles excavated from the Sinjiang and Qinghai area of China, and the linked pearls pattern which are collected at Shosoin, Japan. And from this study, will concentrate on clarifying the linked pearls pattern's condition of the cultural exchange between the East and the West and it's structural variation process. The design of linked pearls pattern delivered to the East through the Silk Road is differed by area. For example, in the Western Pamir Plateau, where the ancient Sogdians mainly lived, the excavated linked pearls pattern's subject were deer or cassowary variated from the West Asian motif. But the ones excavated from Kucha Xingang had Chinese motifs added so they showed Chinese characters or Buddhist Bodhisattva image instead of Helios. Like this, the appearance of new patterns, which were accompanied by structural variations, gradually deviated from the standardized pattern of the Sasanian Persia. And this structural variation process has relations with the construction and arrangement method of various patterns of the after ages. The foliated floral Spray, which is placed at the lozenge space of linked pearls' space, had developed into ogival - shaped pattern (Neunghwamun). And the prevalence of geometrical structure pattern after the 10th century and the unfolding method of Tapjamun which is arranging unit pattern in order, are similar to the linked pearl pattern. In brief, linked pearls pattern accompanied by technical improvement let us understand the polished artistic code from its expression, and has importance in showing universal pattern beyond region and culture.

Feasibility Study on Remodeling Project By Using Real Option Model : Focusing on Apartment House Remodeling (실물옵션을 활용한 공동주택 리모델링 사업성 평가에 관한 연구 - 아파트 리모델링 사례를 중심으로 -)

  • Yeon, JungHoon;Lee, Hyun-Soo;Park, Moonseo;Kim, Sooyoung;Ahn, Joseph
    • Korean Journal of Construction Engineering and Management
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    • v.15 no.1
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    • pp.39-50
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    • 2014
  • After the global financial crisis, domestic construction industry has gone through a rapid recession. This resulted in gradual market shift towards architectural remodeling. Architectural remodeling not only improves residential environment but it has many advantages such as increase of each unit's exclusive area, free space within the horizontal or extension of an annex building, and increase number of household through splitting the household of bigger pyeong, etc. However, in case of the Korean market for apartment remodeling, due to various regulations and problem with business promotion procedures, majority of business is slow despite the figure that remodeling volume is not that small. Also, feasibility study which decides to push ahead public house remodeling business will have a flaw using net present value's law; it has a flaw of not considering properties of each phase of remodeling business and future's uncertainty. Hence, this research will improve the problem of traditional value assessment method of net present value's law. It will also consider one of the real options such as binomial model in order to supplement NPV which is used in current feasibility study. This research was based on real successful cases of public house remodeling and it was possible for feasibility study which was more realistic and valid. This research provided foundation for development of Korean public house remodeling market. There is high anticipation of increasing the validity by improving the problems of current feasibility study and economic efficiency assessment.