• Journal of the Korean GEO-environmental Society
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• v.14 no.7
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• pp.39-50
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• 2013

Crib wall is one of the segmental grid retaining walls using headers and stretchers to establish the framework of the wall. In this method, grids formed by the intersection of headers and stretchers are generally filled with the gravel to maintain the weight of the wall. Therefore, the construction can be carried out with higher speed and much economically when compared with the concrete retaining wall. Furthermore, it has high drain capacity, and environmentally friendly aspects also have been pointed out because the possibility of the planting at the front of the wall. However, in the wooden crib wall method, the relative movement between the individual headers and stretchers was generally recognized, and stress redistribution in the gravel filling was also observed when subjected to the external loading and self-weight of filling. In this study, it was analyzed fracture types and causes of wooden crib wall through detailed investigation and analysis of a large crib wall construction site. As a results, it occurred the damage in the members of 5.7% in a total of 2,315 locations and the damage of header occurred in the members of a header 80.2%. The 65.7% of the damaged header are concentrated in the lower part of crib wall. Therefore, it was analyzed the differences of fracture types and causes of wooden crib wall depending on the installation position and the kinds of members. It is considered basically the members of various forms of distortion and the grain affecting.

• Korean Journal of Environment and Ecology
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• v.22 no.1
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• pp.35-42
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• 2008

This study was conducted to provide basic information that can be used to restore habitats of Nannophya pygmaea. Nannophya pygmaea is an endangered species of wildlife fauna in Korea and its habitats are distributed very scarcely in Korea. Ten wetland sites throughout Korea, where N. pygmaea inhabited (2 sites in Incheon Muui-do, 1 site in Gokseong Singi-ri, 4 sites in Gokseong Wolbong-ri, and 3 sites in Mungyeong Yulsu-ri) were investigated from June 2006 to August 2007. Investigation was made on landscape properties, habitat sizes, vegetation types, water environments, and water sources. N. pygmaea was generally found in the abandoned paddy fields surrounded by mountains. The habitats ranged from $113.4m^2$ to $1,153.1m^2$ in area, and were mostly dominated by Juncus effusus and Persicaria thunbergii. The water level was $2.6\sim7.3cm$, and the water temperature ranged from $16^{\circ}C$ to $27.8^{\circ}C$. The elevation of the habitats ranged from 139 to 243 m above sea level, which was mostly lower than that of other high mountain wetland habitats. In conclusion, the habitats of N. pygmaea can be restored at wetlands, which have similar condition with field habitat such as abandoned paddy fields in the beginning stage of oligotrophy. Because N. pygmaea is sensitive to microtopography and other surrounding environments, the approach to restore the habitats for N. pygmaea should consider those microhabitat conditions shown in this study.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.1
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• pp.1-15
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• 2017

This study investigated the process of change of 32 urban parks designated during the period of Japanese colonial rule according to growth and development of the city in Busan. Particularly, researching included analyizing books, notification, data, and documents relevant to the history of urban planning published by Busan city. As a result, Daejeong Park, Gokwan Park, and Yongdusan Park had been utilized by Japanese residents under the Japanese colonial rule before planning of urban parks, and 32 parks legally specified in 1944 were planned by considering the prevention against disasters. After emancipation, there were an unauthorized building, housing construction, business district, public office, and school facility in the sites of the parks due to the influence of the Korean War and reorganization of urban planning. The majority of parkways and small parks downtown were eliminated. However, unexecuted parks that the government had designed on the edge of town during the Japanese colonial period have become major parks downtown through the city's growth. Yeonji Park, Yangjeong Park, and Danggok Park have been being building as a business of parks for a comfortable city, forming downtown along with the Green-Busan Policy. Thus, 32 parks designated under the Japanese colonial rule have made or got out of use reflecting on the phases of the times of modern Korean society. It turns out that these parks need an investigation about condition for land possession and purchase of the site of the parks in order for social common capital.

• Journal of Conservation Science
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• v.7 no.1
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• pp.9-18
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• 1998

There are about 1470 stone-cultural properties in Korea which have been registered and protected by the government. Representative of them are pagoda, stupa, stone-buddha, stele support of banner pole and stone-lanterns. Most of them have been exposed to and weathered by natural environments. Stone-cultural properties are destroyed and/or destructed mostly by weathering and its related features of rocks. Therefore, it is necessary to conduct geological studies on the weathering phenomena and related features as well as characteristics of the rock itself must be done for the conservation. Thus geological investigation should include detail measurements, rock varieties and phases, structural lineaments of the rock, cause and degree of weathering, degree and patterns of crack development structural stability, identification of reusable parts for restoration, geomorphological characteristics of the site, and etc. The interaction among these factors must be investigated and analyzed, which must be used as basic data to establish the guideline of conservation and to plan for repair and/or restoration. The conservation plan should involve parts to be repaired, method of repair, type of cementing material, the characteristics of rock phases to be supplemented, method for maintaining structural stability, and method to delay or to prevent the rock weathering.

• Journal of Korean Academy of Nursing
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• v.26 no.3
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• pp.605-622
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• 1996

Needle stick injury, in which blood-borne pathogens including Human Immune-Deficiency virus and hepatitis B virus are transmitted, is one of the major occupational hazards that health professionals face everyday. In order to provide basic data for the development of educational programs for health professionals aimed at preventing and effectively managing needle stick injuries, a retrospective descriptive study was carried out .The subjects of the study were 630 health professionals, 499 nurses and 131 physicians, from two university hospitals in Seoul, Korea. Data on episodes of needle stick experiences over the past is months September 1994 through August 1995, were collected between September 1 and 7, 1995. A Questionaire developed by the researcher was used. The frequencies and the percentile score for episodes of needle stick injuries were calculated using the PC-SAS program. The differences and similarities in reference to the structure, career, and specialty variables were analysed by X$^2$-tests. Results are as follows : 1. Of the sample, 521(82.7%) reported a needle stick injury, 33.4% reported 3 or more episodes of needle stick injuries. 2. The needle stick injuries occured in the following processes : process of percutaneous venepuncture for intra-venous injection and infusion(55.3%), medical examination and treatment(48.9%), per-cutaneous venepuncture for blood sampling (46.3%) and intra-muscular injection(42.2%). 3. The study showed that needle stick injuries occured before(19%), during(25%), and after (56%) client treatment. The major causes of needle stick injuries were perceived to be hastiness(82.2%) and carelessness(48.3%). Of these injuries, 91.8% occured in emergency situations. 4. Follow of care for the injury consisted of : treating the injured site immediately using disinfectants(89.7%), reviewing the clinical records of the patient involved(84.2%), immunological investigation for the status of antibodies(11.1%) and self-medication of antibiotics (10.7%). Only 16.3% of the total episodes were founded to have been reported to the administrative unit. 5. The length of clinical experience of the nurses, clinical specialty and length of clinical experience in physicians were found to have influenced the episodes of needle stick injuries ; nurses with less than 1 year and with more than 6 years of clinical experiences had significantly lower levels (X$^2$=25.04, P=.00), surgeons had significantly higher levels (X$^2$=9.89, P=.02) compared to that of internists and interns, higher(X$^2$=4.54, P=.03)than residents.

• Journal of Korean Society of Forest Science
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• v.59 no.1
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• pp.31-36
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• 1983

Flowering time of Pinus rigida Mill and Pinus taeda L, in an $F_1$-hybrid seed orchard was investigated for five years from 1971 through 1975. The two tree species flowered during late April to early May at the observation site, Flowering patterns of the two species of different sex of the same species changed yearly during the five observation years. Floral development of the two species appeared to depend largely on temperature factor during the period of the initiation of floral organs up to flowering provided that other environmental factors are normal. Six-days difference in flowing time between female inflorescence of pitch (flower later) and male inflorescence of loblolly (flower earlier) pines effectively isolated the two species reproductively on population levels. Not all of selected trees of the two species for their synchronized flowering appeared to be useful as parental trees for the establishment of $F_1$-hybrid seed orchards. With the result from this investigation the author suggested to use a modified simple recurrent selection method for pitch-loblolly hybrid pine breeding.

• Journal of Environmental Science International
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• v.11 no.3
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• pp.183-189
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• 2002

Investigation was carried out to observe the dominant bacteria and the effect of metals(Cd ＆ Zn) and its nitrate compound on growth of bacteria isolated from the three tributaries and lower reach of the Nakdong River. Mean CFU(log$_{10}$) level was highest in Kumho River(8.30 CFU), Nam River, Hwang River, and Mulgum followed. Staphylococcus xylosus, Staph. lentus, Pasteurella pneumotropica, Aeromonas hydrophilla were dominant species in each study site. Cadmium powder and Zinc powder showed strong effect to inhibit the growth of Micrococcus spp., Pasteurella pneumotropica, Aeromonas hydrophilla. But, nitrate compounds of Cd and Zn(Cd(NO$_3$)$_2$4$H_2O$, Zn(NO$_3$)$_2$6$H_2O$) did not clearly show the strong effect to inhibit the growth of dominants.s.

• Journal of the Korea Institute of Building Construction
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• v.17 no.3
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• pp.253-260
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• 2017

As global warming became a worldwide issue, a significant effort has been made on the development of technology related to $CO_2$ capture and storage. Geologic sequestration of $CO_2$ is one of those technologies for safe disposal of $CO_2$. Geologic sequestration stores $CO_2$ in the form of supercritical fluid into the underground site surrounded by solid rock, and concrete is used for prevention of $CO_2$ leakage into the atmosphere. In such case, concrete may experience severe damage by attack of supercritical $CO_2$, and especially in contact with underground water, very aggressive form of carbonation can occur. In this work, to prevent such deterioration in concrete, calcium phosphates were added to the portland cement to produce hydroxyapatite, one of the most stable mineral in the world. Temperature rise, viscosity, set and stiffening, and strength development of cement paste incorporating three different types of calcium phosphates were investigated. According to the results, it was found that the addition of calcium phosphate increased apparent viscosity, but decreased maximum temperature rise and 28 day compressive strength. It was found that monocalcium phosphate was found to be inappropriate for portland cement based material. Applicability of dicalcium and tricalcium phosphates for portland cement needs to be evaluated with further investigation, including the long term compressive strength development.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.483-494
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• 2022

Owing to the saturation of ground spaces in downtown areas, underground spaces are being developed increasingly. Underground spaces are utilized for transportation, water supply and sewerage, communication zones, electric power zones, and various cultural complexes. In Korea, for excavating underground spaces, blasting methods using gunpowder such as the New Austrian Tunneling Method (NATM) are mainly used. However, the blasting method causes vibration and noise during tunnel excavation, generating many complaints from residents in the vicinity of the excavation site. To address this problem, various methods have been developed, and recently, vibration and noise have been reduced using deep excavation. This study predicts blast vibration changes according to the depth, under the same blasting and tunnel conditions, using numerical analysis based on the blast vibration measurement data of the GTX-A route, the tunnel cross-section drawings, and ground investigation reports. Furthermore, the necessary separation distance from densely populated areas such as residential areas is suggested by analyzing the trend of decreasing blast vibration according to the distance from ground surface directly above the blasting location.

• Tuberculosis and Respiratory Diseases
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• v.82 no.1
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• pp.27-34
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• 2019

Background: Understanding the burden of disease is important to establish cost-effective treatment strategies and to allocate healthcare resources appropriately. However, little reliable information is available regarding the overall economic burden imposed by chronic obstructive pulmonary disease (COPD) in Korea. Methods: This study is a multicenter observational research on the COPD burden in Korea. Total COPD costs were comprised of three categories: direct medical, direct non-medical, and indirect costs. For direct medical costs, institutional investigation was performed at 13 medical facilities mainly based on the claims data. For direct non-medical and indirect costs, site-based surveys were administered to the COPD patients during routine visits. Total costs were estimated using the COPD population defined in the recent report. Results: The estimated total costs were approximately 1,245 million US dollar (1,408 billion Korean won). Direct medical costs comprised approximately 20% of the total estimated costs. Of these, formal medical costs held more than 80%. As direct non-medical costs, nursing costs made up the largest percentage (39%) of the total estimated costs. Costs for COPD-related loss of productivity formed four fifths of indirect costs, and accounted for up to 33% of the total costs. Conclusion: This study shows for the first time the direct and indirect costs of COPD in Korea. The total costs were enormous, and the costs of nursing and lost productivity comprised approximately 70% of total costs. The results provide insight for an effective allocation of healthcare resources and to inform establishment of strategies to reduce national burden of COPD.