• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.5
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• pp.383-390
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• 2013

The reduction of the maximum acceleration which causes shock for a missile is very important to prevent abnormal operation of a missile and decrease size and cost of missile components. Because the maximum acceleration created by operation of an ejection gas generator occurs in the initial ejection stage, the design parameters which affect initial ejection stage were examined. The igniter and the nozzle closure were selected as design parameters of a gas generator. The maximum acceleration created by the gas generator was examined experimentally by changing of the design parameters. Finally the reduction effect of the maximum acceleration was compared quantitatively by static fire test of a gas generator. The maximum acceleration of the best model which was applied to each optimal design parameter was about 68% reduced than that of the reference model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.689-695
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• 2018

This paper presents the means of controlling the regeneration of a diesel particulate filter (DPF) that is mounted on tactical vehicles to satisfy exhaust gas standards. The DPF captures particulate matter in the exhaust gas and combusts the captured particulate matter. This process is regeneration, which is essential to the normal performance of the DPF. Bad regeneration causes degradation of vehicle performance; worse, it can lead to a vehicle fire. DPF regeneration is performed by control logic. If the regeneration control logic does not properly reflect the operating characteristics of the vehicle, DPF regeneration may not occur. Consequently, it is very important to ensure the DPF operates properly by reflecting the operating characteristics of the tactical vehicle. This study analyzes the operational characteristics of a tactical vehicle and the DPF, and adds proper DPF regeneration control logic. Additionally, this study is intended to simultaneously improve the additional problems that may occur from operating under the added regeneration control logic.

• The Korean Journal of Emergency Medical Services
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• v.9 no.1
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• pp.33-41
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• 2005

In Korea, the number of those who were drowned of the dead by 'accident and injury' ranked the third of causes of death is over 2,300 people a year. So the Ministry of Home Affairs arranged '119 drowning rescue team' at frequent occurrence regions of drowning temporarily as a part of drowning rescue measures during every summer season and made perfection more perfect for safety control and rescue services at prevention areas of accidents. However, considering that the number of professional drowning rescuers is small and it is managed temporarily only for summer, the placement of special rescue team equipped with professional education and qualification should be ensured and quick lifesaving and first-aid treatment should be conducted, since much time is required to arrive at accident place after receiving accident report at 119 office, rapid rescue and relief have not been achieved. Therefore, the placement of special rescue team should be increased for reducing the personal damages by considering regional characteristics and in particular placement of more drowning rescue teams in Jeonnam region which has more seas and rivers is needed This study aims at analyzing relief activities and statistics to cope with water accidents and achieve qualitative growth of first-aid services, examining actual conditions of water accident relief team and personnel assignment, providing first-aid services of good quality and establishing improvement methods to increase operation of relief team.

• Journal of The Korean Society of Clinical Toxicology
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• v.6 no.2
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• pp.117-122
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• 2008

Purpose: Surveys on poisoning usually involves intoxication rather than inhalation, skin contact, etc. Therefore, we examined the characteristics of patients who visited the emergency department in an industrial complex after acute industrial exposure to toxic materials. Methods: Medical records of patients exposed to toxic materials in the work places from April, 2006, to March, 2008, were analyzed retrospectively. Inhalation patients due to fire were excluded. Results: Subjects included 66 patients, with a mean age of $35.4{\pm}10.9$ years, mostly men (91%). Toxicity occurred in 51 patients (77%) by contact, 15 patients (23%) by inhalation, and none by oral ingestion. For toxic materials, 10 patients were exposed to hydrofluoric acid, 8 to hydrochloric acid, 7 to sodium hydroxide, 7 to metals, and others. The face and hands were the most frequent exposure site by contact. Most exposures were caused by accidents, with 29 cases (42%) exposed because of carelessness or not wearing protective equipment. Most complaints were pain on exposure site, but 7 of the inhalation patients complained of dyspnea. The majority of patients with contact exposure were discharged after wound care or observation. After inhalation exposure, 1 patient died and 5 patients were admitted to the intensive care unit. Conclusion: Major causes of workplace exposure were not wearing protective equipment or carelessness. Although contact exposures are usually benign, cautious observation and management are required in patients with inhalation exposure.

• Journal of the Korean Institute of Gas
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• v.12 no.2
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• pp.25-31
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• 2008

Recently risk management based on a quantitative assessment is considered to improve the level of safety in Korea. This paper focuses on the procedure of the quantitative risk assessment for natural gas pipelines. For that purpose, the methods to estimate failure frequency based on failure causes from European Gas Pipeline Incident Data Group and BG Transco, to analyze consequence caused by fire, and to calculate individual risk and societal risk have been proposed systematically in this paper. Risk criteria of individual risk and societal risk have been proposed by considering the environment of pipeline route in Korea. The proposed procedure of quantitative risk assessment may be useful for risk management during the planning and building stages of a new pipeline, and modification of buried pipeline.

• Journal of Internet Computing and Services
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• v.8 no.2
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• pp.43-54
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• 2007

The effective power consumption is the primary issue in a sensor network which consists of the sensor nodes with limited battery power. So, most of the MAC protocols in sensor networks have been designed with the consideration of energy efficiency. Generally, these protocols make use of the listen and sleep mode periodically. However, this approach inevitably causes a long transmission delay on the data forwarding path, which is mainly resulted from the sleep time of the receiver node. This paper deals with a design of DT-MAC(Data Transmission centric MAC) protocol, with minimizes the data transmission delay while it forces each node to consume its energy efficiently. Thus, a node received a packet converts its remained sleep time to the pseudo_listen time, in which the node is able to transmit a packet. With benefit of the pseudo_listen period, the data transmission delay along with the data forwarding path will be shortened as much as it possible. Therefore, DT-MAC protocol is very suitable to the various applications which require a real time sensing data such as disaster and fire alarm.

• The Journal of the Convergence on Culture Technology
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• v.4 no.4
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• pp.429-438
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• 2018

Recently, there has been a tendency for accidents occurring in manufacturing to lead to serious accidents and serious industrial accidents and to extend to community disasters. In accordance with the Third Plan (2015-2019) of the National Security Management Plan, the Safety Administration announces and promotes improvement measures to minimize industrial accidents and disasters. In the case of industrial accidents from KOSHA 2015 to 2017, the accident rate of the metal-related manufacturing industry is 1.57%, which is more than three times higher than the average 0.50% of all industries. As a result of investigating the causes of disasters, 72% of workers were found to be caused by unsafe behaviors. In addition, insecure behaviors are closely related to safety consciousness, and a survey on safety consciousness was conducted for workers in this field. Safety consciousness improvement has the affirmative effect on accident prevention and it is a factor to reduce accidents.

• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.750-754
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• 2014

Quantitative risk analysis has been performed for a pervaporation process for production of high test peroxide. Potential main accidents are explosion and fire caused by a decomposition reaction. As the target process has a laboratory scale, the consequence is considered to belong to Category 3. An event tree has been developed as a model for occurrence of a decomposition reaction in the target process. The probability functions of the accident causes have been established based on the frequency data of similar events. Using the constructed model, the failure rate has been calculated. The result indicates that additional safety devices are required in order to achieve an acceptable risk level, i.e. an accident frequency less than $10^{-4}/yr$. Therefore, a layer of protection analysis has been applied. As a result, it is suggested to introduce inherently safer design to avoid catalytic reaction, a safety instrumented function to prevent overheating, and a relief system that prevents explosion even if a decomposition reaction occurs. The proposed method is expected to contribute to developing safety management systems for various chemical processes including concentration of hydrogen peroxide.

• Journal of Oriental Neuropsychiatry
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• v.21 no.2
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• pp.215-227
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• 2010

Objectives : Jeon-Jeung(癲證) is one of negative symptoms from schizophrenia in Western medecine, which causes flattening of affect, emotional bluntness, and avolition. Compared with positive symptoms of schizophrenia, there is no established treatments that have been proved to be effective for negative symptoms, and since negative symptoms are chronically processed, they finally lead to devastate the mental health. Since Jeon-Jeung(癲證) is usually in set in adolescent period and tends to become chronic through life time, it is important to start getting treatments in early stage by being distinguished from other diseases, such as anxiety disorder. A patient in this case was affective blunting, general weakness, and delusion when sixteen years old. However, he refused to get Western medicine treatment and wanted oriental medicine treatment. Methods : The patient in this case had been suffered from severe stress from his family since he was young and had kept having irregular and unhealthy eating habits. Therefore, he diagnosed stagnant qi transforming into fire(氣鬱化火), heart blood deficiency(心血虛), and spleen-stomach deficiency cold(脾胃虛寒) and since then he had received several treatments including herbal treatment, acupumcture treatment, supportive therapy, and family therapy. These treatments were successful and reduced the level of symptoms. After discharged from the hospital, he had continued receiving outpatient treatment with his family for 8 months and his progress had been still observed after the discharge. Results : The symptoms of patient had been almost reduced and eliminated after he received 29days of admission treatment and the patient got better and better and now lives a normal life 8 months outpatient treatment. Conclusions : This result suggests that our oriental medical treatments and family treatments was effective on schizophrenia.

• Tribology and Lubricants
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• v.38 no.2
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• pp.41-52
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• 2022

Mineral electrical insulating oil, which is widely used in transformers, exhibits excellent cooling performance and transformer efficiency. However, given that it is composed of petroleum-based components, it is weak in terms of biodegradability. This causes environmental problems in case of leakage and a low flash point, which is a factor that would cause great damage in the event of a fire in a substation. In this context, the use of eco-friendly electric insulating oil composed of bio-based vegetable oil and synthetic ester, which has excellent biodegradability and flame retardancy performance, has recently been expanded to the field of electric power, and various research and development (R&D) studies are in progress. According to different research results, vegetable oil and synthetic ester manufacturing technology, thermal stability, oxidation stability, property change, and quality control, which are characteristics of eco-friendly electrical insulating oils, are major factors affecting the maintenance of insulating oil properties. In addition, power companies have established and operated quality control standards according to the use of eco-friendly electrical insulating oil as they expand the exploitatoin of renewable energy in electricity production. In particular, deterioration and oxidation characteristics were jointly identified in R&D as an important influencing factor according to the content of saturated and unsaturated fatty acids present in vegetable oils and synthetic esters in power transformer applications.