• Journal of the Society of Disaster Information
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• v.20 no.1
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• pp.47-59
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• 2024

Purpose: This study aims to propose measures for the prevention of fire and explosion accidents within manufacturing facilities by improving the existing classification criteria for hazardous locations based on the leakage patterns of flammable liquids. The objective is to suggest ways to safely manage ignition sources and combustible materials. Method: The hazardous locations were calculated using "KS C IEC 60079-10-1," and the calculated explosion hazard distances were visualized in 3D. Additionally, the formula for the atmospheric dispersion of flammable vapors, as outlined in "P-91-2023," was utilized to calculate the dispersion rates within the hazardous locations represented in 3D. Result: Visualization of hazardous locations in 3D enabled the identification of blind spots in the floor plan, facilitating immediate recognition of ignition sources within these areas. Furthermore, when calculating the time taken for the Lower Explosive Limit (LEL) to reach within the volumetric space of the hazardous locations represented in 3D, it was found that the risk level did not correspond identically with the explosion hazard distances. Conclusion: Considering the atmospheric dispersion of flammable liquids, it was concluded that safety management should be conducted. Therefore, a method for calculating the concentration values requiring detection and alert based on realistically achievable ventilation rates within the facility is proposed.

• Journal of Korean Society of Disaster and Security
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• v.12 no.1
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• pp.11-21
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• 2019

This study assessed the risk of disaster by using QRE(Quick Risk Estimation - UNISDR Roll Model City of Basic Evaluation Tool) tools for three natural disasters and sixteen social disasters managed by the Seoul Metropolitan Government. The criteria for selecting 19 disaster types in Seoul are limited to disasters that occur frequently in the past and cause a lot of damage to people and property if they occur. We also considered disasters that are likely to occur in the future. According to the results of the QRE tools for disaster type in Seoul, the most dangerous type of disaster among the Seoul city disasters was "suicide accident" and "deterioration of air quality". Suicide risk is high and it is not easy to take measures against the economic and psychological problems of suicide. This corresponds to the Risk ratings(Likelihood ranking score & Severity rating) "M6". In contrast, disaster types with low risk during the disaster managed by the city of Seoul were analyzed as flooding, water leakage, and water pollution accidents. In the case of floods, there is a high likelihood of disaster such as localized heavy rains and typhoons. However, the city of Seoul has established a comprehensive plan to reduce floods and water every five years. This aspect is considered to be appropriate for disaster prevention preparedness and relatively low disaster risk was analyzed. This corresponds to the disaster Risk ratings(Likelihood ranking score & Severity rating) "VL1". Finally, the QRE tool provides the city's leaders and disaster managers with a quick reference to the risk of a disaster so that decisions can be made faster. In addition, the risk assessment using the QRE tool has helped many aspects such as systematic evaluation of resilience against the city's safety risks, basic data on future investment plans, and disaster response.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.54-61
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• 2000

Amalgam, though a widely used dental material, does not bond to the tooth substrate Therefore, retentive preparation of the cavity is necessary. Such amalgam restorations, until corrosion products form and plug the margin, will show significant marginal leakage. Unless this is prevented early on, saliva and bacteria may enter the cavity causing postoperative hypersensitivity, dissolution and collapse of the restoration, discoloration of the margin and secondary caries, leading to shortened life-span of the restoration and pulpal pathosis. Recently, a method of restoration has been introduced whereby tooth material can be preserved, cavity margin can be sealed and preventive treatment of pit and fissure can be administered while retaining all the advantages of conventional amalgam restorations. Such sealed amalgams involve removing the carious lesion without extending the cavity for prevention and using pit and fissure sealants to seal cavity margins and pit and fissures to reduce microleakage. In this study, finishing of the amalgam and sealant application were performed after different intervals following of amalgam restoration to compare the microleakage of sealed and conventional amalgam restorations. Thirty bicuspids were prepared with Class V cavity preparations on the buccal and lingual surfaces. After amalgam placement, they were divided into the following groups and treated accordingly. Group 1 : Polishing after 24 hours Group 2 : Immediate sealant application without polishing Group 3 : No polishing, but sealant applied after thermocycling 500 times After treatment, the samples were thermocycled 500 times between $5^{\circ}C$ and $55^{\circ}C$ with a dwell time of 30 seconds. After thermocycling, the samples were dipped into 1% methylene blue kept in a $37^{\circ}C$ incubator at 100% humidity for 24 hours. The teeth were then embedded in resin and cut bucco-lingually along the tooth axis and observed with a stereomicroscope to determine the degree of microleakage, The following results were obtained : 1. Group 2 showed the least microleakeage, while group 1 showed the greatest. 2. Group 1 showed significantly greater microleakage compared to group 2 (p<0.05). However, no significant differences were found between group 1 and 3(p>0.05). No significant differences in microleakage were also found between cup 2 and 3(p<0.05).

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.980-987
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• 2012

Nonpoint source pollution causes leaks and overtopping, depending on the state of the sewer network as well as aggravates the pollution load of the aqueous water system as it is introduced into the sewer by wash-off. According, the need for efficient sewer monitoring system which can manage the sewage flowrate, water quality, inflow/infiltration and overflow has increased for sewer maintenance and the prevention of environmental pollution. However, the sewer monitoring is not easy since the sewer network is built in underground with the complex nature of its structure and connections. Sewer decontamination mechanism as well as pipe network monitoring and fault diagnosis of water network system on system analysis proposed in this study. First, the pollution removal pattern and behavior of contaminants in the sewer pipe network is analyzed by using sewer process simulation program, stormwater & wastewater management model for expert (XP-SWMM). Second, the sewer network fault diagnosis was performed using the multivariate statistical monitoring to monitor water quality in the sewer and detect the sewer leakage and burst. Sewer decontamination mechanism analysis with static and dynamic state system results showed that loads of total nitrogen (TN) and total phosphorous (TP) during rainfall are greatly increased than non-rainfall, which will aggravate the pollution load of the water system. Accordingly, the sewer outflow in pipe network is analyzed due to the increased flow and inflow of pollutant concentration caused by rainfall. The proposed sewer network monitoring and fault diagnosis technique can be used effectively for the nonpoint source pollution management of the urban watershed as well as continuous monitoring system.

• Journal of Gastric Cancer
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• v.6 no.2
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• pp.103-108
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• 2006

Purpose: The circular stapled Billroth I gastrectomy has been gradually popularized because of several advantages. Thus, this study aims to identify what to be supplemented for the safety of this technique by examining the potential complication after the circular stapled Billroth I gastrectomy. Materials and Methods: This study selected 594 patients who underwent the circular stapled Billroth I gastrectomy because of the gastric cancer in our department of surgery from Jan. 1998 to Dec. 2004 as the subjects. As of Jan. 2001 when the bleeding on the anastomosis site was visually checked through the small incision at the opposite curvature to the lesion of the stomach to be resected and so the operation was completed, the patients were divided into the Group I (n=219) and Group II (n=375), which were the patients before and after Jan. 2001, respectively. Then, the clinical characteristics and postoperative anastomotic complications of both groups were compared. Results: For the comparison of complications between two groups, the anastomotic leakage was found in four cases in Group I and three cases in Group II (p=0.196). The stenosis on the anastomosis region was not observed in both groups. The bleeding on the anastomosis region illustrates the statistically significant difference between Group I and Group II, with 43 cases and 2 cases, respectively (P=0.0019). Conclusion: The circular stapled Billroth I gastrectomy is recommended because of several advantages of this technique. However, the bleeding on the anastomosis site may be indicated as the critical issue. Accordingly, the visual check on the bleeding on the anastomosis site during the operation will improve the safety of circular stapler.

• The Korean Society of Law and Medicine
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• v.20 no.1
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• pp.109-132
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• 2019

Recently, medical accidents related to surgical procedures have increased. In addition, the media reported that some of these accidents were involved in health crimes. Patient-advocate groups have called for mandatory establishment and management of CCTV in operating rooms. There is a lot of discussion among the interested parties, so it is necessary to review the relevant laws and regulations. The purpose of this study is to identify the characteristics of CCTV in operating rooms and to review legislations related to establishment and management of the CCTV in operating rooms. Medical institutions use CCTV for management of facilities and patient safety and install it in operating rooms optionally. The Constitution guarantees the privacy and the privacy of correspondence of every citizen, but it can be limited by the law for public welfare. Currently, however, there is no existing law about establishment and management of the CCTV in operating rooms and it can be defect of legal system. Under the current legislations, it is likely that the Self-determination can be violated due to the characteristic of healthcare provider when CCTV is mandatorily installed in operating room. In addition, the regulations on access and leakage of confidential information known by operator are insufficient. So that, the safety of the visual data might be threatened. Furthermore, unless the period and the place of storage of the visual data are clearly defined, it is highly unlikely to meet the original purpose of patient safety and prevention of medical accidents. This study is meaningful as there is few previous study on this topic although the need for legal review about this is growing and several bills are being proposed. It is expected that the results of this study can be utilized as basic data for enactment or amendment of the laws and regulations about establishment and management of CCTV in operating rooms.