• Journal of Korea Water Resources Association
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• v.50 no.10
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• pp.673-679
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• 2017

In this paper a method for estimating the 'service life' and 'residual life' of a water pipe based on the Water Pipe Network Performance Evaluation(WPNPE) results of Water Supply Technical Diagnosis was developed for efficient maintenance of water pipes. The residual life of a pipe was defined as the difference between the service life and elapsed time since installation. The service life was defined as the time when a pipe reaches the reference score for determining deteriorated pipes that was used in the WPNPE. The pipe evaluation criteria and deterioration scores used in the WPNPE for the case study area were considered as independent variables in the multiple regression model for estimating the service life and residual life of the pipes in the area. To estimate the service life for the pipes the reference scores for determining deteriorated pipes were used as the values of the variables that represent the deterioration scores in the constructed regression models. Subsequently, the statistics of the service life and residual life of the pipes in the case study area were presented and analyzed in comparison with the service life defined by the Local Public Enterprizes Act.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.730-736
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• 2019

The demand for natural gas, which is considered an environmentally friendly energy source, is increasing, and at the same time, the market share of large pipelines for natural gas supply is increasing continuously. On the other hand, the corrosion of such large pipelines reduces the efficiency of natural gas transportation. Therefore, this study aims to establish a strategy for securing the patent rights of related technologies through quantitative analysis of patents on energy-independent high-efficiency corrosion prevention technology for large-scale pipelines for natural gas supply. In this patent technology trend study, Korean, US, Japanese, and European patents filed, published, and registered by June 2018 were analyzed, and a technical classification system and classification criteria were prepared through expert discussion. To use fuel cells as an external power source to prevent the corrosion of natural gas large-scale pipelines, it is believed that rights can be claimed using an energy control system and methods having 1) branch structures of pipeline and facility designs (decompressor/compressor/heat exchanger) and 2) decompression/preheating and pressurization/cooling technology of high pressure natural gas.

• Archives of Plastic Surgery
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• v.47 no.3
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• pp.217-222
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• 2020

Background Surgical reconstruction of chronic wounds is often infeasible due to infection, comorbidities, or poor viability of local tissues. The aim of this study was to describe the authors' technique for improving the regenerative and antimicrobial potential of a combination of modified nanofat and platelet-rich plasma (PRP) in nonhealing infected wounds. Methods Fourteen patients met the inclusion criteria. Fat tissue was harvested from the lower abdomen following infiltration of a solution of 1,000 mL of NaCl solution, 225 mg of ropivacaine, and 1 mg of epinephrine. Aspiration was performed using a 3-mm cannula with 1-mm holes. The obtained solution was decanted and mechanically emulsified, but was not filtered. Non-activated leukocyte-rich PRP (naLR-PRP) was added to the solution before injection. Patients underwent three sessions of injection of 8-mL naLR-PRP performed at 2-week intervals. Results Thirteen of 14 patients completed the follow-up. Complete healing was achieved in seven patients (53.8%). Four patients (30.8%) showed improvement, with a mean ulcer width reduction of 57.5%±13.8%. Clinical improvements in perilesional skin quality were reported in all patients, with reduced erythema, increased thickness, and increased pliability. An overall wound depth reduction of 76.6%±40.8% was found. Pain was fully alleviated in all patients who underwent re-epithelization. A mean pain reduction of 42%±33.3% (as indicated by visual analog scale score) was found in non-re-epithelized patients at a 3-month follow-up. Conclusions The discussed technique facilitated improvement of both the regenerative and the antimicrobial potential of fat grafting. It proved effective in surgically-untreatable infected chronic wounds unresponsive to conventional therapies.

• The Korean Society of Law and Medicine
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• v.20 no.2
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• pp.261-285
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• 2019

The essential policy of suicide prevention is to continuously manage and treat suicide attempted people through data base related to suicide retry rate and follow-up study report. In Korea, only few people are allowed to follow-up by the Personal Information Protection Act. As a result, the research participation rate and the service participation rate are rather low, so that the research participants is limited to a part of the suicide attempted people. Therefore, the policy proposals to be improved in the Ministry of Health and Welfare Act were examined comparatively in order to increase the practical utilization of the suicide prevention about Article 14 and Article 20 of the Suicide Prevention Act. As a criterion for policy improvement, measures for non-discrimination of information to be considered in terms of technical and ethical dimensions and non-profit research and medical information for medical purposes were suggested. In addition to the severity of the suicide, the suicide risk was assessed and the criteria for the objective assessment of the follow-up observation were considered in consideration of the severity of the suicide.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.1
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• pp.113-119
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• 2014

Recently, R.O.K. Navy is increasing re-usability of design data and application of M&S(Modeling and Simulation) through the establishment of collaborative product development environment focused on Naval Ship Product Model(NSPM). As a result, the reliability of the result of design is getting better, and furthermore, a study to improve quality of construction through simulation of production/operation is in progress. Accordingly, the database construction of design data and the DB(Database) quality become important, but there was not research related to those or it was just initial state. This paper conducted research about system of the quality verification process of shape elements which compose NSPM based on the quality verification guideline of NSPM as the result of the precedent study. The hull surface was limited as verification object. The study to verify two things that application of basic drawing by the cad model of hull surface, and whether there is error in the geometric quality of cad model was progressed. To achieve this goal, the verification criteria and algorithm were defined and the prototype system which is based on was developed.

• Journal of the Korean Society of Safety
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• v.25 no.6
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• pp.34-39
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• 2010

The purpose of this study is to suggest objective evaluation model as a plan to utilize as opportunity in establishing judgment standard of mutual inspection criteria and to upgrade inspection ability by reviewing and analyzing level of danger and importance in advance based on inspection results of inspection institutions regarding tower cranes used in construction fields. Tower crane is a mechanical device transporting construction supplies and heavy materials to places over 20~150M high from the ground for the period ranging from a short time of 2~3 months to two years after being installed in construction sites in vicinity of buildings or structures and is an important facility indispensable for construction sites. However, since use period after installation is short and professional technical ability of technicians working on-site about of tower crane is poor, systematic and quantitative safety management is not carried out As a part of researches on procedure of RBI(Risk Based Inspection) possible to apply to Knowledge Based System based on knowledge and experiences of experts as well as to tower cranes for solving these problems, quantitative RPN(Risk Priority Number) was applied to RPN utilizing technique of FMEA(Failure Mode and Effect Analyses). When general RBI 80/20 Rule was applied parts with high level of risks were found out as wire rope, hoist up/down safety device, reduction gear, and etc. However, since there are still many insufficient parts as risk analyses of tower crane were not established, it is necessary for experts with sufficient experiences and knowledge to supplement active RBI techniques and continuous researches on tower cranes by sharing and setting up data base of important information with this study as a starting point.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.801-810
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• 2013

The main purpose of this study is to reframe sustainability or sustainable development concept in the field of planning in consideration of climate change and natural hazards. The new concept is expected to provide a theoretical foundation for upcoming hazard mitigation measures addressing climate change. The first and main argument of the new concept is that environmental protection should be inclusive enough to address urban (or community) security from current natural hazards. The second is that the balance between structural and nonstructural mitigation measures is critical to cope more effectively with extreme natural hazards in the era of climate change and also with conflicts driven by three goals of sustainability--environmental protection, economic development, and social justice. The following studies, based on this new concept of sustainablity, are expected (1) to address new participation methods for the conflict resolution, (2) to explore detailed and substantive planning strategies and creative technical and institutional solutions for environmental protection, natural hazard mitigation, and conflict resolution. Two of APFM(the Associated Programme on Flood Management)'s three natural hazard risk criteria, Exposure and Vulnerability, may guide the exploration.

• The Journal of the Acoustical Society of Korea
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• v.39 no.4
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• pp.303-317
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• 2020

Extracorporeal Shock Wave Therapy (ESWT) is an innovative treatment in chronic musculoskeletal pain management and cardiovascular diseases. In this study, we surveyed the acoustic shock wave outputs from the domestically used focal type ESWT devices. The survey data were collected through 30 technical documents registered to the Ministry of Food and Drug Safety (MFDS), Rep. Korea. The results show that the focusing geometry varies largely, 5 mm to 65 mm in the focal length, 3 mm to 30 mm in focal width, and 4 mm to 108 mm in focal depth. The maximum positive pressure (P+) ranges from 7 MPa to 280 MPa, the focal Energy Flux Density (EFD) from 0.0035 mJ/㎟ to 35 mJ/㎟, and the energy per pulse (E) from 0.737 mJ to 80.86 mJ. All domestic PE-type (five) and one EM-type domestic devices included in the analysis of the correlation between P+ and EFD are shown to be far beyond the usual ranges and do not comply with expected correlation so that the reliability of their data was suspected. For the suspected, post-performance tests are required by a recognized testing agency. MFDS guidelines need to be revised so that the pass criteria for the shock wave acoustic outputs can be based on the clinical tests for indications.

• Journal of Environmental Health Sciences
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• v.44 no.1
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• pp.44-54
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• 2018

Objectives: To protect individuals working at the site as well as the surrounding general population from a chemical accident, several emergency exposure guidance levels have been used to set a level of concern for certain chemicals. However, a level of concern has not been established for many substances that are frequently used or produced in large quantities in Korean workplaces. In the present study, we investigated the guidance levels for protecting populations from chemical exposure and the estimation of level of concern using acute inhalation and oral toxicity data. Methods: The number of chemicals to which emergency exposure guidance levels (e.g., ERPG-2, AEGL-2, PAC-2, and IDLH) can be applied were determined among 822 hazardous chemicals according to the 'Technical Guidelines for the Selection of Accident Scenarios (revised December 2016)'. The ERPG and AEGL values were compared across all three tiers for the 31 substances that appeared on both lists. We examined the degree of difference between the emergency exposure guidance levels and the estimates of level of concern calculated from acute inhalation or acute oral toxicity data. Results: Among the 822 hazardous chemicals, emergency exposure guidance levels can be applied to 359 substances, suggesting that the estimates of level of concern should be calculated using acute toxicity data for 56.3% of the hazardous chemicals. When comparing the concordance rates of ERPG and AEGL for 31 substances, the difference between the two criteria was generally small. However, about 40% of the substances have values diverging by more than three-fold in at least one tier. Such discrepancies may cause interpretation and communication problems in risk management. The emergency exposure guidance levels were similar to the estimates of level of concern calculated using acute inhalation toxicity data, but the differences were significant when using acute oral toxicity data. These results indicate that the level of concern derived from acute oral toxicity data may be insufficient to protect the population in some cases. Conclusion: Our study suggests that the development of standardized guidance values for emergency chemical exposure in the Korean population should be encouraged. It is also necessary to analyze acute toxicity data and fill the information gaps for substances that are important in Korean workplace situations.

• Journal of Embryo Transfer
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• v.18 no.3
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• pp.243-248
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• 2003

Sperrnatogenesis, the process by which the male germ-line stem cells(GSCs; type A spermatogonia) divide and differentiate to produce the mature spermatozoa, occurs in the seminiferous tubules of the testis. The GSCs proliferate actively to produce two types of cells: other GSCs and differentiating spermatogonia. GSCs have unipotentcy, devoted solely to the generation of sperm. The function of GSCs has broad implications for development, disease, and evolution. Spermatogenesis is fundamental for propagation of species and the defects of this system can result in infertility or disease. The ability to identify, isolate, culture, and alter GSCs will allow powerful new approaches in animal transgenesis and human gene therapy relating to infertility. Until recently, research on stem cells in the testis has been limited because of technical difficulties in isolating and identifying these cell populations. Here, we were trying to find out optimal conditions for in vitro culture of GSCs for identifying and isolating GSCs. We collected mouse GSCs from 3-days old mouse by two-step enzyme digestion method. GSCs were plated and grown on mouse embryonic fibroblasts in Dulbecco's modified Eagle's medium (DMEM) containing 15％ fatal bovine serum, 10 mM 2-mercaptoethanol, 1％ non-essential amino acids, 1 ng/$m\ell$ bFGF, 10 $\mu$M forskolin, 1500 U/$m\ell$ human recombinant leukemia inhibitory factor (LIF). Over a period 3∼5 days, GSCs gave rise to large multicellular colonies resembling those of mouse pluripotent stem cells. After 5th passages, cells within the colonies continued to be alkaline phosphatase and Oct-4 positive and tested positive against a panel of two immunological markers(Integrin $\alpha$ 6 and Integrin $\beta$ 1) that have been recognized generally to characterize GSCs. SSEA-1, SSEA-3, and SSEA-4 also showed positive signals. Based on our data, these GSCs-derived cultures meet the criteria for GSCs itself and even other pluripotent stem cells. We reported here the establishment of in vitro cultures from mouse male GSCs.