• Fire Science and Engineering
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• v.29 no.4
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• pp.39-48
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• 2015

This research was done to develop a duct-dedicated intelligent fire detection system to prevent fires and minimize fire damage of the industrial duct having a high fire risk. To understand the fire hazards of the ducts, the analysis was centered on the Daegu Textile Industrial Complex, where industrial ducts are used frequently. With this in the background, dedicated fire detectors and fire alarm control panel, which can prevent fires and to minimize fire damages to the ducts, were designed and produced, after which the performance was confirmed. As a result of performance experiments, it was shown that a duct-dedicated intelligent fire detection system had excellent adaptability and temperature accuracy. Through real-time temperature monitoring of the inside of the ducts, it was confirmed that duct fires could be efficiently extinguished by stepwise control of linkage facilities according to the setting temperature.

• Fire Science and Engineering
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• v.29 no.4
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• pp.73-80
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• 2015

In this study, the conditions of explosion range of gasoline, which is used as combustion improver, are experimentally analyzed. Two types of compartment, which is the small scale ($0.5m{\times}0.5m{\times}1.0m$) and the middle scale ($0.5m{\times}0.5m{\times}1.0m$), are mocked-up and the auto-control systems are installed in order to measure the vaporized gasoline and the moment of pressure, ignition time and maximum pressure. In case the maximum flammable limit of gasoline is up to 22.4 Vol% not the generalized range of 1.4~7.6 Vol% when nichrome igniter of $700^{\circ}C$ is used. These results can be appled to the analytical prediction of fire identification in the field of explosion.

• Fire Science and Engineering
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• v.26 no.5
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• pp.79-84
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• 2012

Combustion characteristics of outdoor advertisement materials were evaluated for fire risk assessment about fire expanding. At this study, the flame retardancy and the limiting oxygen index (LOI) was measured by UL 94 and ASTM D 2863 respectively. At the result of flame retardancy, foamex was V-0 grade and those of others were out of grade. LOI measurement showed that the LOI of foamex was highest in the samples. The cone calorimeter test was done by ISO 5660-1 to find the combustion characteristics. The cone calorimeter test showed that the outdoor advertisement materials were not good to prevent of fire expanding. The time to ignition (TTI) of flex was the fastest and the peak heat release rate (PHRR) as well as the total heat release (THR) of acrylic panel was higher than those of others.

• Journal of Information Technology Services
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• v.19 no.1
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• pp.145-158
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• 2020

With the development and widespread application of online shopping, the number of online consumers has increased. With one click of a mouse, people can buy anything they want without going out and have it sent right to the doors. As consumers benefit from online shopping, people are becoming more concerned about protecting their privacy. In the group buying scenario described in our paper, online shopping was regarded as intra-group communication. To protect the sensitive information of consumers, the polynomial-based encryption key sharing method (Piao et al., 2013; Piao and Kim, 2018) can be applied to online shopping communication. In this paper, we analyze security problems by using a polynomial-based scheme in the following ways : First, in Kamal's attack, they said it does not provide perfect forward and backward secrecy when the members leave or join the group because the secret key can be broken in polynomial time. Second, for simultaneous equations, the leaving node will compute the new secret key if it can be confirmed that the updated new polynomial is recomputed. Third, using Newton's method, attackers can successively find better approximations to the roots of a function. Fourth, the Berlekamp Algorithm can factor polynomials over finite fields and solve the root of the polynomial. Fifth, for a brute-force attack, if the key size is small, brute force can be used to find the root of the polynomial, we need to make a key with appropriately large size to prevent brute force attacks. According to these analyses, we finally recommend the use of a relatively reasonable hash-based mechanism that solves all of the possible security problems and is the most suitable mechanism for our application. The study of adequate and suitable protective methods of consumer security will have academic significance and provide the practical implications.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.5
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• pp.1362-1373
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• 2004

In studying the specific effects of some drugs, animals under experiments get some stress through laboratory environments, drug injection, and adaptation period. These stimuli do harms on liver function. Nowadays studies on liver intoxication and its protection are under research, but the function of dissolution is rarely under studies. It is widely accepted that Soshiho-tang has function of clearing away low spirits, and that it enables liver bloods to move stronger, and to have calm mind. So I injured rats liver by injectioning CCI₄. And the rats took in Soshiho-tang solution. I made a comparison between the functions before and after rat's liver damage. There are many representative serums used to note an index on liver damage. I used total protein, albumin, ALP, GOT, GPT activity, P450, SOD, Catalase, GST, GR, and GPx. I got the following results. When Soshiho-tang was injected after CCI4 intoxication, total protein and albumin decreased. When Soshiho-tang was injected, ALP decreased, compared with control group. When Soshiho-tang was injected after CCI₄ intoxication, AST and ALT decreased. When Soshiho-tang was injected before CCI₄ intoxication, P450 was restrained. When Soshiho-tang was injected, LPO was all restrained. When Soshiho-tang was injected, SOD, Catalase, GST, GR, and, GPx increased. These results show that blood test reveals that it is good to inject Soshiho-tang after CCI₄ intoxication, but that it is good to inject Soshiho-tang before CCI₄ intoxication in case of P450, LPO, SOD, Catalase, GST, GR, and GPx. It is estimated that the medication period and time of liver damage by CCI₄ have counter results, and that it needs more modified study.

• Korean Journal of Pharmacognosy
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• v.41 no.4
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• pp.255-263
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• 2010

Kojongsi persimmon (Diospyros kaki) is the major cultivar of astringent persimmon in southern of Korea. Kojongsi persimmon leaf has been traditionally used for acute and chronic diseases in Oriental countries. The purpose of this study was undertaken to investigate the antioxidative activities of the extract of Kojongsi persimmon leaf during growth. We investigated the antioxidant effects of the persimmon leaf extracts during growth on total polyphenol, total flavonoid, electronic donating ability (DPPH), nitrite (NO) scavenging and superoxide dismutase (SOD)-like activity. The next, we investigated the possible cell protective effects of the persimmon extract treatment against ultraviolet B (UVB)-induced injury in HaCaT keratinocytes. The contents of total polyphenol and flavonoid in leaf extract of Kojongsi persimmon were increased in time-dependent manner. In Jun, DPPH and NO radical scavenging and SOD-like activities in the leaf extract of Kojongsi persimmon was increased to the highest. However, the antioxidant activities in persimmon varieties were not any difference. The cell cytotoxicity by UVB irradation in HaCaT keratinocytes was significantly increased with the compared to the control group. However, the treatment of leaf extract of Kojongsi persimmon in HaCaT keratinocytes was shown to protective effect against UVB-induced cell cytotoxicity. These results suggest that the leaf extract of Kojongsi persimmon has potent antioxidant activity, and protective effect against UVB-induced keratinocyte injury. Thus, these properties may be contributed in the care of acute and chronic diseases.

• Korean Journal of Veterinary Research
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• v.40 no.3
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• pp.563-573
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• 2000

Periodic outbreaks of Newcastle disease (ND) caused by velogenic viscerotropic ND virus (vvNDV) has become a major concern in Korea nowadays. Throughout last epidemic, the winter season in 2000, most chicken flocks infected early, under 2-4 weeks of age, showed high mortality up to 50-100%. Serum samples collected from 201 breeder, 284 layer and 112 broiler chicken flocks were examined to evaluate the efficacy of various vaccination methods and programs routinely used for mass vaccination in the field poultry farms. Despite repeated live vaccination, most poultry flocks vaccinated by drinking water route using nipple water supply system failed to produce solid active immune response to NDV during the growing time. In the present study, we applied the spray vaccination technique using Ulvavac or Desvac sprayer to the experimental poultry flocks and examined the efficacy of live vaccination effects induced by it under field condition. Measurable antibody to NDV as well as early protection against vvNDV challenge were found in poultry flocks vaccinated by spray route. Further, we did not found significant post vaccination reactions caused by spray vaccination if properly administered. These data indicate that the spray vaccination will be safe and reliable mass vaccination method for the prevention of ND.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.18 no.1
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• pp.58-63
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• 2010

Introduction : Head trauma is the main cause of death in aircraft crash. In a Michigan study of structurally survivable, fatal accidents, 80% of the fatally injured had received head trauma. We tried to develop a new helmet for passengers, and perform its efficiency test. Methods : An aircraft helmet requires an excellent protection against head trauma, lightness, and small volumes. In addition, it must be wearable, fire resistant, and non toxic when it is burning. We developed two new helmets made from silicone foam which met all theses requirements. One was thin (2.5cm), and the other was thick (6.3cm). These looked like a motorcycle helmet and had only a soft silicone as liner material without an outer hard shell. Therefore we can carry them easily inside aircrafts. The standard test for helmet is Snell's drop test. It measures the impact acceleration of head shaped metal wearing helmet during we drop it at certain heights. Impact sites were total 5 sites (front, back, right, left and top) for each helmet. All these sites were impacted twice. Results : The thickness of impact sites varied from 2.5cm to 6.3cm. The impact acceleration of 2.5cm thickness site when it was dropped from 1.0 meter was 379g. But, that of 6.3cm thickness site when it was dropped from 1.5 meter was only 163g. Unfortunately, both helmets didn't meet the Snell Standard for motorcycle helmets. Discussion : If we add suitable outer hard shell, and change its thickness and design, the efficiency will be increased. A study indicated that helmet could reduce the risk of head trauma up to 85%. We made helmet for passengers in aircraft crash for the first time. If we improve its weak points, it will decrease the frequency of head trauma in aircraft craft.

• Journal of the Korea Furniture Society
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• v.18 no.4
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• pp.317-323
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• 2007

Almost all the people, particularly the rural people are directly dependent on the continued productivity of natural resources, like water, soils, forests and fisheries. But the overuse by the extremely high population pressures has degraded the natural resources into severe widespread deforestation. The degradation of natural resources, particularly the plant resources has been a great concern for socio-economic and sustainable development of the country. The Forests in Bangladesh have been depleted and degraded in volume, area, and quantity, thus requiring urgent forest protection by identifying the causes of forest loss. There are so many causes of deforestation and loss of genetic resources such as; the timber industry, which, legal or not, are cutting too many trees; indigenous forest dwellers, having their own types of problems; migrants, who, because of problems in their places of origin, have decided to move to the forests and the government through its Forest Department which is not able or willing to implement suitable policies to regulate the cutting trees and to prevent illegal cutting. Because it is a time consuming task to mitigate the first and second sets of factors, we recommend involving forest dwellers in forestry practices as much as possible and taking necessary steps to alleviate the third and fourth sets and thereby reduce the rate of forest depletion. Accordingly, a number of strategies that should be adopted to halt the loss of remaining forest cover are discussed.

• Fire Science and Engineering
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• v.25 no.1
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• pp.50-56
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• 2011

In recently years, occurrences of lightning return strokes have been increased by global worming effect and intensity of lightning impulse voltage and current accompanied by lightning discharges has being strengthening. In Korea, 560 thousand lightning discharges happened in 200S. According to the increasing frequencies of lightning, human deaths and damages to the structure have been increased steadily. Electric fire caused by lightning return strokes due to the breakdown between power line and ground line from the ground potential rise on a process of the lightning impulse current through to the ground. The damages of lightning were occurring at same time in the neighboring areas of the lightning point. In order to protect from the lightning stroke, we made a suggestion to use protection devices and equipotential bonding at the dangerous areas. The analysis results of electric fires caused by lightning would be utilized to investigate and to find accurate fire cause in the fire scenes.