• Journal of the Korean Institute of Gas
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• v.20 no.5
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• pp.9-16
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• 2016

Buried pipe system is subject to leak or rupture due to internal and external defects with age. Especially, if the pipeline is designed for pressurized gas, the leak can wreak a devastating on its surrounding area. The current method of setting up underground gas pipeline is based on OGP criteria of applying one tenth of the inner pipe pressure. The criteria is applied irrespective of their burial depth or pipe's properties. At times, even the whole safety measures are totally ignored. Considering the magnitude of possible damage from a gas leakage, a precise analytical tool for the risk assessment is urgently needed. The study was conducted to assess possible scenarios of gas accidents and to develop a computer model to minimize the damage. The data from ETA was analyzed intensively, and the model was developed. The model is capable of predicting jet fire influence area with comprehensive input parameters, such as burial depth. The model was calibrated and verified by the historic accident data from Edison Township, New Jersey, the United States. The statistical model was also developed to compare the results of the model in this study and the existing OGP model. They were in good agreement with respect to damage predictions, such as radiation heat coming from 10 meters away from the heat source of gas flame.

• Journal of Environmental Science International
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• v.25 no.4
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• pp.505-516
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• 2016

With the development of nanotechnology, nanomaterials are used in various fields. Therefore, the interest regarding the safety of nanomaterial use is increasing and much effort is diverted toward establishment of exposure assessment and management methods. Occupational exposure limits (OELs) are effectively used to protect the health of workers in various industrial workplaces. This study aimed to propose an OEL for domestic multi-walled carbon nanotubes (MWCNTs) based on animal inhalation toxicity test. Basic procedure for development of OELs was examined. For OEL estimation, epidemiological study and quantitative risk assessment are generally performed based on toxicity data. In addition, inhalation toxicity data-based no observed adverse effect level (NOAEL) and benchmark dose (BMD) are estimated to obtain the OEL. Three different estimation processes (NEDO in Japan, NIOSH in USA, and Baytubes in Germany) of OELs for carbon nanotubes (CNTs) were intensively reviewed. From the rat inhalation toxicity test for MWCNTs manufactured in Korea, a NOAEL of $0.98mg/m^3$ was derived. Using the simple equation for estimation of OEL suggested by NEDO, the OEL of $142{\mu}g/m^3$ was estimated for the MWCNT manufacturing workplace. Here, we used test rat and Korean human data and adopted 36 as an uncertainty factor. The OEL for MWCNT estimated in this work is higher than those ($2-80{\mu}g/m^3$) suggested by previous investigators. It may be greatly caused by different physicochemical properties of MWCNT and their dispersion method and test rat data. For setting of regulatory OELs in CNT workplaces, further epidemiological studies in addition to animal studies are needed. More advanced technical methods such as CNT dispersion in air and liquid should be also developed.

• The Journal of Korean Medicine
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• v.27 no.3 s.67
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• pp.107-131
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• 2006

Background and Aims: Dansamtongmek-tang (DSTMT) and Dansamsengmek-san (DSSMS) have been used for many years as therapeutic agents for the acute stage of cerebrovascular disease, hypertension and hyperlipidemia in Oriental medicine, but the effects of DSTMT and DSSMS on hyperlipidemia and safety for cell damage are not yet well-known. This study was done to investigate the effects of DSTMT and DSSMS on hyperlipidemia. Methods: In vivo test: after administering DSTMT and DSSMS to SHR and ICR occurred hyperlipidemia for 3 weeks, we analyzed body weight, cholesterol levels. TG, HDL-chol, LDL-chol, LDH in plasma, brain, liver and kidney tissue, and DNA by RT-PCR. In vitro test: after administering DSTMT and DSSMS to human hepatocellular carcinoma in hypoxia, we observed cell cohesion by light microscope, analyzed the inflow of Ca2+ by confocal laser scanning microscope and DNA by RT-PCR. Results: DSTMT significantly decreased the levels of triglyceride and increased the levels of HDL-cholesterol in SHR, and significantly decreased the levels of LDL-cholesterol and body weight and increased the levels of HDL-cholesterol in ICR. DSSMS significantly decreased body weight, total cholesterol levels, LDL-cholesterol, LDH and cardiac risk factor (CRE) in SHR and significantly decreased the levels of total cholesterol, triglyceride, LDL-cholesterol, LDH and CRF in ICR. DSTMT had an effect on protecting cells from damage by inhibiting production of p53 mRNA, and in DSSMS, by inhibiting production of p53 mRNA and p21 mRNA after hypoxia. DSTMT effectively blocked off Ca2+ at low density, but DSSMS effectively blocked off Ca2+ at high density. Both DSTMT and DSSMS had an effect on inhibiting lipid metabolism by blocking off production of apo B mRNA. Conclusions: These results suggest that DSTMT and DSSMS might be usefully applied for treatment of hyperlipidemia and suppression of brain damage.

• Journal of Chest Surgery
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• v.48 no.4
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• pp.258-264
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• 2015

Background: This study aimed to evaluate the therapeutic results and safety of pectoralis major muscle turnover flaps in the treatment of mediastinitis after coronary artery bypass grafting (CABG) procedures. Methods: Data regarding 33 patients with post-CABG deep sternal wound infections (DSWIs) who underwent pectoralis major muscle turnover flap procedures in the Emam Reza and Ghaem Hospitals of Mashhad, Iran were reviewed in this study. For each patient, age, sex, hospital stay duration, remission, recurrence, and associated morbidity and mortality were evaluated. Results: Of the 2,447 CABG procedures that were carried out during the time period encompassed by our study, DSWIs occurred in 61 patients (2.5%). Of these 61 patients, 33 patients (nine females [27.3%] and 24 males [72.7%]) with an average age of $63{\pm}4.54$ years underwent pectoralis major muscle turnover flap placement. Symptoms of infection mainly occurred within the first 10 days after surgery (mean, $10.24{\pm}13.62days$). The most common risk factor for DSWIs was obesity (n=16, 48.4%) followed by diabetes mellitus (n=13, 39.4%). Bilateral and unilateral pectoralis major muscle turnover flaps were performed in 20 patients (60.6%) and 13 patients (39.4%), respectively. Complete remission was achieved in 25 patients (75.7%), with no recurrence in the follow-up period. Four patients (12.1%) needed reoperation. The mean hospitalization time was $11.69{\pm}6.516days$. Four patients (12.1%) died during the course of the study: three due to the postoperative complication of respiratory failure and one due to pulmonary thromboembolism. Conclusion: Pectoralis major muscle turnover flaps are an optimal technique in the treatment of post-CABG mediastinitis. In addition to leading to favorable therapeutic results, this flap is associated with minimal morbidity and mortality, as well as a short hospitalization time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.62-68
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• 2016

The feeder cable assembly is an automotive part used for telecommunication. If it malfunctions, the control and safety of the automobile can be put at risk. ALT (Accelerated Life Testing) is a testing process for products in which they are subjected to conditions (stress, strain, temperatures, etc.) in excess of their normal service parameters in an attempt to uncover faults and potential modes of failure in a short amount of time. Failure is caused by defects in the design, process, quality, or application of the part, and these defects are the underlying causes of failure or which initiate a process leading to failure. Thermal shock occurs when a thermal gradient causes different parts of an object to expand by different amounts. Thermal shock testing is performed to determine the ability of parts and components to withstand sudden changes in temperature. In this research, the main causes of failure of the feeder cable assembly were snapping, shorting and electro-pressure resistance failure. Using the Coffin-Manson model for ALT, the normal conditions were from Tmax = $80^{\circ}C$ to Tmin = $-40^{\circ}C$, the accelerated testing conditions were from Tmax = $120^{\circ}C$ to Tmin = $-60^{\circ}C$, the AF (Acceleration Factor) was 2.25 and the testing time was reduced from 1,000 cycles to 444 cycles. Using the Bxlife test, the number of samples was 5, the required life was B0.04%.10years, in the acceleration condition, 747 cycles were obtained. After the thermal shock test under different conditions, the feeder cable assembly was examined by a network analyzer and compared with the Weibull distribution modulus parameter. The results obtained showed good results in acceleration life test mode. For the same reliability rate, the testing time was decreased by a quarter using ALT.

• Herbal Formula Science
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• v.16 no.2
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• pp.133-144
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• 2008

Recently, people are becoming fatter in most parts of the world. Obesity is regarded as an important risk factor to adversely affect the health of humans, associated with hypertension, hyperlipidemia, diabetes, and cardiovascular diseases. In the present study, therefore, we tested the short time efficiency and safety of Bangpoongtongsungsan as a drug to decrease body weight in subjects with obesity. A total 48 volunteers (24 man, 24 woman) with body mass index (BMI : weight in kg divided by square of height in meters) of $23㎏/m^2$ participated in clinical study for 12 weeks, from 2008, March 01 to 2008, Jun 30. The subjects was received a dietary supplement of 12 pieces hard capsules per day (4 pieces in one, 3 times in a day) during the clinical study. At the end of clinical study, body weight of subjects was significantly decreased from $72.21{\pm}11.44\;kg$ to $70.53{\pm}11.67\;kg$ (p<0.05). Waist circumferences of subjects were reduced $91.58{\pm}6.43\;cm$ to $85.25{\pm}7.70\;cm$ (p<0.05). Also, a BMI of subjects was significantly decreased $26.07{\pm}2.35\;kg/m^2$ to $25.63{\pm}2.63\;kg/m^2$ (p<0.05). Particularly, a decrease in body weight, waist circumferences, and BMI was more significant in woman than man. But, other biochemical levels including lipid and glucose in plasma had no changes at the end of clinical study. In conclusion, administration of Bangpoongtongsungsan in subjects with high body weight fat could inhibit obesity associated with a decrease in body weight, waist circumferences, and BMI.

• Applied Chemistry for Engineering
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• v.30 no.5
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• pp.556-561
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• 2019

In this study, the physical and chemical analyses of petroleum residues (pyrolized fuel oil, PFO) were conducted and major components were selected to investigate their fire and explosion characteristics. Major component distribution areas of the PFO were identified via the GC-SIMDIS and MALDI-TOF analyses. In addition, the qualitative analysis of major component distribution areas was performed by GC-MS analysis. Major components of pyrolysis residue were selected based on the results of various analyses such as EA, SARA and TGA. As a result, benzene, toluene and xylene were selected as major components. Finally, the process hazard analysis software tool (PHAST) analysis was performed to investigate the range of maximum damage effect in case of fire and explosion. Toluene presented the highest risk due to the radiation effect of $227kW/m^2$ and 118 m in the case of jet fire. Xylene and benzene showed the maximum radiant heat values of 114 and $151kW/m^2$, respectively. It was also confirmed from the analysis of pasquill stability and wind speed that the radiant heat increased up to 55% according to wind speed in benzene, which was considered to be a main factor increasing the influence range.

• 한국노년학
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• v.38 no.1
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• pp.225-241
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• 2018

Self-driving is meaningful activity for older persons because it enlarges the range of activity and provides opportunities for social participation. Driving is a complex activity that requires integration of physical, cognitive and sensory functions and is influenced by human and psychological factors. Age related functional deterioration affects the driving ability of older drivers. The purpose of this study is to investigate the factors affecting the risk of accidents and driving cessation of elderly drivers through systematic literature review. MEDLINE, EMBASE, Cochrane Library, KoreaMed, Pubmed were used for searching articles published from 2007 to 2017. 'aged', 'aging', 'automobile driving', 'age factors' were used as search terms and 18 articles were finally selected for analysis among 1,458 articles. In result of the study, the most significant effect showed in the physical domain, the driving habit and the performance function. The most frequent used tools evaluated driving habit and the cognitive function. In demographic characteristics, there was a correlation with the driving discontinue according to sex and age. This study emphasizes the necessity of preparing measures for safety driving with elderly. In addition, it suggests the necessity of systematically services such as individual education programs based on various driving cessation related factors of the elderly.

• Journal of Biomedical Engineering Research
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• v.42 no.6
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• pp.259-267
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• 2021

Recently, the market for personal health care and medical devices based on Bluetooth Low Energy(BLE) has grown rapidly. BLE is being used in various medical data communication devices based on low power consumption and universal compatibility. However, since data errors occurring in the transmission of medical data can lead to medical accidents, it is necessary to analyze the causes of errors and study methods to reduce data error. In this paper, the minimum communication speed to be used in medical devices was set to at least 800 byte/sec based on the wireless electrocardiography regulations of the Ministry of Food and Drug Safety. And the data loss rate was tested when data was transmitted at a speed higher than 800 byte/sec. The factors that cause communication data error were classified, and the relationship between each factor and the data error rate was analyzed through experiments. When there were two or more activated peripherals connected to the central, data error occurred due to channel hopping and bottleneck, and the data error rate increased in proportion to the communication distance and the number of activated peripherals. Through this experiment, when the BLE is used in a medical device that intermittently transmits biosignal data, the risk of a medical accident is predicted to be low if the number of peripherals is 3 or less. But, it was determined that BLE would not be suitable for the development of a biosignal measuring device that must be continuously transmitted in real time, such as an electrocardiogram.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.2
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• pp.62-73
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• 2022

As the competition among the autonomous vehicle (AV, here after) developers are getting fierce, Korean government has been supporting developers by deregulating safety standards and providing financial subsidies. Recently, some OEMs announced their plans to market Lv3 and Lv4 automated driving systems. However, these market changes raised concern among public road management sectors for monitoring road conditions and alleviating hazardous conditions for AVs and human drivers. In this regards, the authors proposed a methodology for monitoring road infrastructure to identify hazardous factors for AVs and categorizing the hazards based on their level of impact. To evaluate the degrees of the harm on AVs, the authors suggested a methodology for managing road hazard factors based on vehicle performance features including vehicle body, sensors, and algorithms. Furthermore, they proposed a method providing AVs and road management authorities with potential risk information on road by delivering them on the monitoring map with node and link structure.