• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.1 no.1
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• pp.47-55
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• 1991

Exposure level of respirable coal dust of underground coal mines in Taebaek area was evaluated. Personal air samplers with 10-mm nylone cyclones were attached to the coal workers including drillers, coal cutters, their assistants, haulers, and separators. Log-normality of respirable dust exposure concentration were tested by Kolmogorov-Smirnov one-sample test. Differences of means of respirable dust exposure concentration between work sites were tested by one-way ANOVA test and multiple comparison(Scheffe) test. And differences of respirable dust exposure concentration of principal and assistant workers in drilling sites and in coal faces were tested by paired t-test. Relation of respirable dust exposure concentration for the principal workers and their assistants in drilling sites and in coal faces were tested by regression analysis. The results were as follows : 1. All of the respirable dust concentration were log-normally distributed. 2. There were not only significantly different means of exposure concentration between drillers and coal cutters but between coal cutters and haulers. 3. Means of exposure concentration of drillers and drilling assistants were not significantly different. And means of exposure concentration of coal cutters and coal cutting assistants were not different.

• Journal of Plant Biology
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• v.17 no.4
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• pp.18-22
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• 1974

Counts of herb stems were made with each systematic grid sized 10cm by 1300cm within six apparently homogeneous herb layers under the open young Japanese red pine, Pinus densiflora, stands. The stands had often been subjected to strong human interferences such as burning, cutting, grazing, and denuding since human settlement until the conservation scheme practiced in these stands for last decade. In addition, amounts of loss of ignition and field capacity were determined to detect soil heterogeneity among and within the stands. The values of information measure of diversity(H), and Hurlbert's probability of interspecfic encounter(Δ), obtained here do not show any consistent correlation. The amount of interspecific competetion(Δ1), the ratio of interspecific to intraspecific competetion(Δ4), Levin's niche breadth(Sh), and species evenness(V), increase, while the amount of intraspecific competetion decrease, as the soil factors become favorable. One stand examined does not follow the above trends, which is more young and shows strong within site heterogeneity of the soil factors. The stand includes pioneer species which is not detectable without detailed observation. It is argued that in stable or favorable environment more intense interspecific competetion and less intraspecific competetion might occur, but this situation does not necessarily always bring smaller niche breadth. In this connection, the results support Hurlbert's contention that the two components of diversity should be analyzed separately.

• Journal of the Korea Institute of Building Construction
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• v.9 no.1
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• pp.95-101
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• 2009

Although the concept of RTLS is very unfamiliar to construction industry, recently it is popular in other industry, such as logistics, ship building, mobile telecommunication based on state-of-the-art information technology. Effective resource management using cutting-edge information technology makes it possible to succeed a project with saving the time and cost. And effective information management in construction project can be achieved by the new technologies such as RFID, WEB-based internet, DB technology, real-time monitoring technology, etc. This paper suggest the characteristics and applicability of the international standard electric waves to be used for the real-time locating system (RTLS) on the viewpoint of transmission loss in construction field to monitor and manage resources of construction project effectively The two types of electric waves based on the international standard is to be suggested after surveying the as-is technology in the related industries and then is analyzed to find out the characteristics of those by the concept of the electric wave transition loss in the several construction situations. Two main electric waves, the 2.4GHz and the 433MHz technologies as the international standard is researched on the applicability to the indoor environment of construction site.

• Journal of the Korea Safety Management & Science
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• v.16 no.3
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• pp.45-54
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• 2014

The average injury rate in sawmilling industry for the last 5 years is 4.99%, which means that more than 200 injuries have occurred in that industry every year. Because the first step in risk assessment is the hazard identification, it is very important to know how to define the hazard and nature of harm. We analyzed 643 accident records of three years(2010-2012) and carried out site survey for the same cases. As a result, the most common types of work at the time of injury in sawmilling industry were removing jammed wood 81(12.8%), wood carrying task 52(8.1%), wood cutting 49(7.6%), travelling table log band saw 41(6.4%), maintenance 37(5.8%) etc. In addition, there were statistically significant differences in some analysis factors such as injured body parts, employment size, and handling material among different working places. Therefore, it is concluded that differentiated prevention efforts are necessary in each workplace.

• Journal of the Korea Institute of Building Construction
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• v.4 no.3
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• pp.83-91
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• 2004

With labor shortage and high-wage era, the construction cost is rising and the construction business is dull, demanding the construction environment of Korea to raise profitability through major cost savings and rationalization of construction management. However, although reinforcing bar(rebar) work, which greatly effects the building's safety, endurance, and construction time, is an important phase in construction, it holds serious problem of quality and productivity deterioration due to its characteristic of intensive-labor and maintaining of old work methods resulting in poor management, and costs increase. Therefor in this study to investigate current situation and problems of rebar work and to find methods of betterment, a survey was conducted to site engineers and individuals in division of cost estimate of domestic construction company. The survey questions were on the subjects of (1) calculating rebar quantity, (2) ordering and procurement, (3) rebar cutting and bending, and (4) rebar work management. Method of improvement was sought by analyzing the results of the survey

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.139-142
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• 2003

As composite materials are gaining wide acceptance in aircraft structure, repair of damaged composite is becoming an important issue. The issues in composite repair include high cost, material interchangeability, water ingression, and structural integrity. To address these problems, researchers have studied on the composite repair in various aspects. In this paper, an Internet-based advisory service (called Repair Advisory Service, RAS) for composite repair is proposed to increase efficiency for repair process. In the RAS system the web browser is used as its user interface, which provides easy access to the service. The RAS server provides web-based tools for failure prediction, Structural Repair Manual (SRM), automated prepreg cutting process, material properties, inventory and knowledge base. The computer codes implemented for repair design estimate the tensile failure and shear failure of repaired structures. The prediction of failure is based on the maximum strain criterion for tensile failure while elastic-perfect plastic shear failure model is applied for interfacial failure. The OEM's SRM is provided in the PDF format for viewing and searching by web browsers instead of looking up paper version SRM. The knowledge base in this site offers a room to share and distribute ideas, memos, publications, or suggestions from the repair engineers. The fabrication tool of RAS reads repair geometry from engineers then generates a CNC toolpath to cut prepreg patches. The RAS service is open to public and available at http://nano.gsnu.ac.kr/. Broad feedback from field technicians and engineers is welcome to improve the usefulness of RAS.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.15-18
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• 2009

Due to its high dependency of manpower, construction work has several difficulties in terms of quality control, imbalance of supply and demand of qualified manpower, safety management for them and improvement of production. Such problems related to the management can be at some degree solved by introducing an automation facility. Since the unique environment of a construction site in the past was not structured, it is very hard to introduce a facility to automate construction work from operation of the equipment to assignment of where to work. This is a preliminary research for automation of construction work. In this study, the trend of development of a cutting-edge technology, RTLS, was researched and analyzed in order to review the possibility of utilizing RTLS in construction work and present a control mechanism for construction equipment. Although the presented mechanism is at the concept stage, which still has lots of restrictions to be solved, the application of the RTLS will be very much feasible. That is, if linkage of the study between the RTLS and the automation of construction is built, it will be expected to contribute to many fields such as cost reduction through efficient and systemic management, the reduction of construction period and precise construction as well as raising the level of the automation of domestic construction work.

• Journal of Dental Anesthesia and Pain Medicine
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• v.15 no.2
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• pp.101-103
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• 2015

In oral and maxillofacial surgery, many complications associated with nasotracheal tube can be caused. In this case, we reported ballooning tube damage of nasotracheal tube during orthognathic double-jaw surgery and replacement of tube through cut down of tube and tube exchange using airway exchange catheter. The patient scheduled for high Le Fort I osteotomy and bilateral sagittal split osteotomy was intubated nasotracheally with nasal endotracheal tube. During maxilla osteotomy, air bubble was detected in the oral blood. In spite of our repeated ballooning, the results were the same so we changed damaged tube using airway exchange catheter aseptically. Tiny and superficial cutting site was detected in the middle of pilot tube. As we know in our case, tiny injury impeded a normal airway management and prevention is important.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.1 no.1
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• pp.95-101
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• 1998

In order to seek a efficiency of site cooperation and slope stabilization in a rock sloping work, it would rather take into consideration, in its importance, a concurrent performance of civil works and landscaping works than give any part a special priority. It can enable us to achieve an expanded scope of landscaping works and improvement of slope scenery via this sort of cooperation. However, this can not be achieved without assurance on the slope stabilization and scenic view of the project owner, and further via this cooperation, environmentally familiar works can be performed, becoming natural environment and minimizing damages on surrounding scenery and environment. It is foreseeable that improvement of functions of civil equipment, introduction of technology and development of landscaping materials can facilitate an improvement in the betterment of slope scenery. Landscaping related parties need to enhance their understanding of rock sloping and scenic view based on knowledge on the fundermental understanding of slope stabilization and on the base rock characteristics.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.3
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• pp.143-151
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• 1998

To develop restoration technologies of natural environment, which is destroyed through the urbanization, industrialization, and the increase of leisure industry, the development of environmental restoration material and those application is greatly needed. Concerning this current issue, an experiment has been conducted to test and an experiment has been conducted to test and analyze the conditions of nutritonal propagation of willow cutting, which is known as a plant with rapid propagation and good growth capability under bad soil conditions and its wide ecological amplitude. 24 various kinds of willow cuttings -2~6 cuttings for each species -were placed into the earth for 57 days and measured the lengths and the diameters of willow cuttings, the possibility of root formation, the total number, and the total length of new shoots and roots. 23 among 24 willow cuttings tested were showing a great growing capacity and a number of new shoots and roots were observed in a relatively short time. This proved that salix is an adequate plant material for quick environmental restoraton . Besides, those willow cuttings could be classified for different site conditions through comparing the ratio of the underground part to the aboveground in total length. The results are as follows; S. dependens, S. matsudana, S. babylonica are the most suitable species for quick vegetaton and S. gracilistyla,S. myricoides,S. alba 'sercia' for erosioni control.