• Journal of Korean Society of societal Security
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• v.3 no.2
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• pp.65-71
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• 2010

This study was conducted to provide a method for fire suppression in a central area inside the roof of a wooden cultural property using a gas extinguishing apparatus, which is used as one of fire suppression methods with view to preventing valuable wooden properties inherited from ancestors from being destructed by fire. For a wooden property, it is very difficult to suppress fire when combustion spreads to a central area inside its roof, so it is impossible to put out a fire without destructing it. Such a fire fighting apparatus as a sprinkler, etc., installed in modern structures, is very effective, but the possibility of damaging a cultural property is highly probable after installment and operation, which leads to its low adaptability to a wooden property. Thus, the necessity of developing a fire suppress ion apparatus was raised to minimize the said problem and to obtain the desired results, and the need of making a plan on the installment was also raised based on the results of a test whose validity was proven. The central area inside a roof is a traditional - architectural style which is found in Korean wooden structures only, so it is impossible to discover similar cases in foreign countries. For this reason, this study was conducted to verify the effectiveness by developing a fixed fire suppression apparatus designed considering the speed and effectiveness in fire suppression. This study was sequentially carried out in the following steps. First, a frame for this study was made and the specific plan on a fire suppression method was established. Then, a fire suppression apparatus was installed. In the first step, the effectiveness for fire suppression was tested by installing valve open - punched - main water pores, and in the second step, the same effectiveness was tested by valve opened - punched - injection ports. For a wooden property similar to "Sungnyemun"(Gate of Exalted Ceremonies), its central area of the roof decides whether the fire suppression is successful or not, so the opinions on how to put out a fire were presented in this study, and thus the objective data to establish a method on fire suppression in a wooden structure(cultural property) was secured. Lastly, a scientific verification in the effectiveness for fire suppression measures was presented by installing a gas - fixed fire suppression apparatus.

• Journal of the Korea Concrete Institute
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• v.26 no.4
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• pp.429-440
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• 2014

Since the World Trade Center and Pentagon attacks in 2001, terror, military attack, or man-made disaster caused impact, explosion, and fire accident have frequently occured on civil infrastructures. However, structural behavior researches on major Prestressed Concrete (PSC) infrastructures such as bridges, tunnels, Prestressed Concrete Containment Vessel (PCCVs), and LNG tanks under extreme loading are significantly lacking. Especially, researches on possible secondary fire scenarios after terror, bombing, collision of vehicles and vessels on concrete structures have not been performed domestically where most of the past researches related to extreme loadings on structures focused on an independent isolated extreme loading scenario. Due to the outcry of public concerns and anxiety of potential terrorist attacks on major infrastructures and structures, a study is urgently needed at this time. Therefore, in this study, the bi-directional prestressed concrete $1400{\times}1000{\times}300mm$ panels applied with 430 kN prestressing force using unbonded prestressing thread bars were experimentally evaluated under impact, fire, and impact-fire combined loadings. Due to test site restrictions, impact tests were performed with 14 kN impactor with drop heights of 10m and 3.5 m to evaluate impact resistance capacity. Also, fire and impact-fire combined loading were tested using RABT fire loading curve. The measured residual strength capacities of PSC and RC specimens applied with impact, fire, impact-fire combined loadings were compared with the residual strength capacity of undamaged PSC and RC specimens for evaluation. The study results can be used as basic research data for related research areas such as protective design and numerical simulation under extreme loading scenarios.

• Journal of Bio-Environment Control
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• v.23 no.4
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• pp.293-302
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• 2014

This study was carried out to develop rain shelter which can make an appropriate size and environment for Chinese cabbage rainproof cultivation. Fifty three farms with chinese cabbage rainproof cultivation system have been investigated to set up width and height of rain shelter. Mostly the width of 6m was desired for rain shelter and the height of 1.6m for their eaves, so these values were chosen as the dimensions for rain shelter. After an analysis of their structural safety and installation costs by the specifications of the rafter pipe, Ø$25.4{\times}1.5t$ and 90cm have been set as the size of rafter that such size costs the least. This size is stable with $27m{\cdot}s^{-1}$ of wind velocity and 17cm of snow depth. Therefore it is difficult to apply this dimension to area with higher climate load. In order to sort out such problem, the rain shelter has been designed to avoid damage on frame by opening plastic film to the ridge. Once greenhouse band is loosen by turning the manual switch at the both sides of rain shelter and open button of controller is pushed then switch motor rises up along the guide pipe and plastic film is opened to the ridge. Chinese cabbage can be damaged by insects if rain shelter is opened completely as revealed a field. To prevent this, farmers can install an insect-proof net. Further, the greenhouse can be damaged by typhoon while growing Chinese cabbage therefore the effect of an insect-proof net on structural safety has been analyzed. And then structural safety has been analyzed through using flow-structure interaction method at the wind condition of $40m{\cdot}s^{-1}$. And it assumed that wind applied perpendicular to side of the rain shelter which was covered by insect-proof net. The results indicated that plastic film was directly affected by wind therefore high pressure occurred on the surface. But wind load on insect-proof net was smaller than on plastic film and pressure distribution was also uniform. The results of structural analysis by applying pressure data extracted from flow analysis indicated that the maximum stress occurred at the end of pipe which is the ground part and the value has been 54.6MPa. The allowable stress of pipe in the standard of structural safety must be 215 MPa or more therefore structural safety of this rain shelter is satisfied.

• Journal of Bio-Environment Control
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• v.23 no.2
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• pp.109-115
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• 2014

This study examined the uplift bearing capacity of spiral steel pegs according to the degree of soil compaction and embedded depth in a small-scaled lab test. As a result, their uplift bearing capacity increased according to the degree of soil compaction and embedded depth. The uplift bearing capacity under the ground condition of 85% compaction rate especially recorded 48.9 kgf, 57.9 kgf, 86.2 kgf and 116.6 kgf at embedded depth of 25 cm, 30 cm, 35 cm and 40 cm, respectively, being considerably higher than under other ground conditions. There were huge differences in the uplift bearing capacity of spiral steel pegs according to the compaction conditions of ground. Their maximum uplift bearing capacity was 116.6 kgf under the ground condition of 85% compaction rate and at embedded depth of 40 cm, and it is very high considering the data of spiral steel pegs. It is thus estimated that wind damage can be effectively reduced by careful maintenance of ground condition surrounding spiral steel pegs. In addition, spiral steel pegs will be able to make a contribution to greenhouse structural stability if proper installation methods are provided including the number and interval according to the types of greenhouse as well as fixation of plastic film. The findings of the study indicate that the optimal effects of spiral steel pegs for greenhouse can be achieved at embedded depth of more than 35cm and compaction degree of more than 85%. The relative density of the model ground in the test was 67% at compaction rate of 85%.

• Geophysics and Geophysical Exploration
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• v.11 no.1
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• pp.52-59
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• 2008

We have developed a new deep-towed marine DC resistivity survey system. It was designed to detect the top boundary of the methane hydrate zone, which is not imaged well by seismic reflection surveys. Our system, with a transmitter and a 160-m-long tail with eight source electrodes and a receiver dipole, is towed from a research vessel near the seafloor. Numerical calculations show that our marine DC resistivity survey system can effectively image the top surface of the methane hydrate layer. A survey was carried out off Joetsu, in the Japan Sea, where outcrops of methane hydrate are observed. We successfully obtained DC resistivity data along a profile ${\sim}3.5\;km$ long, and detected relatively high apparent resistivity values. Particularly in areas with methane hydrate exposure, anomalously high apparent resistivity was observed, and we interpret these high apparent resistivities to be due to the methane hydrate zone below the seafloor. Marine DC resistivity surveys will be a new tool to image sub-seafloor structures within methane hydrate zones.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.6
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• pp.422-429
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• 2013

It is generally known that the increase of the Earth surface temperature due to the global warming together with the land desertification by rapid urban development has caused severe climate and weather change. In desert or desertification land, it is observed that there are always severe flooding phenomena, even if desert sand has the high porosity, which could be believed as the favorable condition of rain water infiltration into ground water. The high runoff feature causes possibly another heavy rain by quick evaporation with the depletion of underground water due to the lack of infiltration. The basic physics of desert flooding is reasonably assumed due to the thermal buoyancy of the higher temperature of the soil temperature than that of the rain drop. Considering the importance of this topic associated with water resource management and climate disaster prevention, no systematic investigation has, however, been reported in literature. In this study, therefore, a laboratory scale experiment together with the effort of numerical calculation have been performed to evaluate quantitatively the basic hypothesis of run-off mechanism caused by the increase of soil temperature. To this end, first, of all, a series of experiment has been made repeatedly with the change of soil temperature with well-sorted coarse sand having porosity of 35% and particle diameter, 2.0 mm. In specific, in case 1, the ground surface temperature was kept at $15^{\circ}C$, while in case 2 that was high enough at $70^{\circ}C$. The temperature of $70^{\circ}C$ was tested as this try since the informal measured surface temperature of black sand in California's Coachella Valley up to at 191 deg. $^{\circ}F$ ($88^{\circ}C$). Based on the experimental study, it is observed that the amount of runoff at $70^{\circ}C$ was higher more than 5% compared to that at $15^{\circ}C$. Further, the relative amount of infiltration by the decrease of the surface temperature from 70 to $15^{\circ}C$ is about more than 30%. The result of numerical calculation performed was well agreed with the experimental data, that is, the increase of runoff in calculation as 4.6%. Doing this successfully, a basic but important research could be made in the near future for the more complex and advanced topic for this topic.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.2
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• pp.107-117
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• 2004

If doubtlessly contributes much to agriculture and rural development. The roles can be summarized as; 1. to activate rural areas and to provide more comfortable and safe rural life with equivalent services to those in urban areas, facilitating distance education, tole-medicine, remote public services, remote entertainment etc. 2. To initiate new agricultural and rural business such as e-commerce, real estate business for satellite officies, rural tourism and virtual corporation of small-scale farms. 3. To support policy-making and evaluation on optimal farm production, disaster management, effective agro-environmental resource management etc., providing tools such as GIS. 4. To improve farm management and farming technologies by efficient farm management, risk management, effective information or knowledge transfer etc., realizing competitive and sustainable farming with safe products. 5. To provide systems and tools to secure food traceability and reliability that has been an emerging issue concerning farm products since serious contamination such as BSE and chicken flu was detected. 6. To take an important and key role for industrialization of farming or lam business enterprise, combining the above roles.

• 한국노년학
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• v.38 no.3
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• pp.569-592
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• 2018

This study purported to investigate the current state of human rights of older adults residing in rural areas of Korea. The study utilized, as an analytic framework, 4 priority directions (1. "older persons and development", 2. "rural area development", 3. "advancing health and well-being into old age", and 4. "ensuring enabling and supportive environments") with 13 task actions recommended by Madrid International Plan of Action on Ageing (MIPAA). Furthermore, the study examined gender differences in all items included in the analytic framework. Data was collected by the face-to-face survey on 800 subjects aged 65 and over. Statistical analyses were conducted using STATA 13.0 program. The main results were summarized in order of 4 priority directions as follows. First, average working hours per day were 6.2, and men reportedly participated in economic activities and needed job training more than women, while women participated in lifelong education programs more than men. Awareness of fire and disaster prevention facilities was low in both genders. Second, accessibility to the support center for the elderly living alone as well as protective services for the vulnerable elderly was found to be low. IT-based services and networking were used more by men than women, and specifically, IT-based financial transactions and welfare services were least used. Third, medical check-ups and vaccinations were well received, while consistent treatments for chronic illnesses and long-term care services were relatively less given. In addition, accessibility to mental health service centers was considerably low. Fourth, although old house structures and the lack of convenience facilities were found to be circumstantial risk factors for these elders, experiences of receiving housing support services were scarce. The elderly were found to rely more on informal care, and concerns for their care were higher in women than men. Plus, accessibility to elderly abuse services was markedly low. Based on these results, discussed were implications for implementing policies and practical interventions to raise the levels of the human rights for this population.

• Journal of Climate Change Research
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• v.5 no.1
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• pp.13-19
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• 2014

In the past, Korea agro-climatic zone except Jeju-do was classified into nineteen based on rice culture by using air temperature, precipitation, and sunshine duration etc. during rice growing periods. It has been used for selecting safety zone of rice cultivation and countermeasures to meteorological disasters. In this study, the climatic variables such as air temperature, precipitation, and sunshine duration of twenty agro-climatic zones including Jeju-do were compared decennially (1970's, 1980's, 1990's, and 2000's). The meteorological data were obtained in Meteorological Information Portal Service System-Disaster Prevention, Korea Meteorological Administration. The temperature of 1970s, 1980s, 1990s, and 2000s were $12.0{\pm}0.14^{\circ}C$, $11.9{\pm}0.13^{\circ}C$, $12.2{\pm}0.14^{\circ}C$, and $12.6{\pm}0.13^{\circ}C$, respectively. The precipitation of 1970s, 1980s, 1990s, and 2000s were $1,270.3{\pm}20.05mm$, $1,343.0{\pm}26.01mm$, $1,350.6{\pm}27.13mm$, and $1,416.8{\pm}24.87mm$, respectively. And the sunshine duration of 1970s, 1980s, 1990s, and 2000s were $421.7{\pm}18.37hours$, $2,352.4{\pm}15.01hours$, $2,196.3{\pm}12.32hours$, and $2,146.8{\pm}15.37hours$, respectively. The temperature in Middle-Inland zone ($+1.2^{\circ}C$) and Eastern-Southern zone ($+1.1^{\circ}C$) remarkably increased. The temperature increased most in Taebak highly Cold zone ($+364mm$) and Taebak moderately Cold Zone ($+326mm$). The sunshine duration decreased most in Middle-Inland Zone (-995 hours). The temperature (F=2.708, df=3, p= 0.046) and precipitation (F=5.037, df=3, p=0.002) increased significantly among seasons while the sunshine duration decreased significantly(F=26.181, df=3, p<0.0001) among seasons. In further study, it will need to reclassify agro-climatic zone of rice and it will need to conduct studies on safe cropping season, growth and developing of rice, and cultivation management system etc. based on reclassified agro-climatic zone.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.1
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• pp.45-63
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• 2019

The number of domestic construction company is expanding every year while the construction workers' exposure to disaster risk is increasing due to technological advancements and popularity of high-rise buildings. In particular, the industry faces greater fatalities and severe large scale accidents because of construction industry characteristics including influx of foreign workers with different language and culture, large number of aged workers, outsourcing, high place work, heavy machine construction. The construction industry is labor-intensive, which is to be completed under given timeline and consists of unique working environment with a lot of night shifts. In addition, when a fixed construction budget is not secured, there is less investment in safety management resulting in poor risk management at the construction site. Taking account that the construction industry has higher accident risk rate and fatality rate, risky and unique working environment, and various labor pool from foreign to aged workers, preemptive safety management through risk factor identification is a mandatory requirement for the construction industry and site. The study analyzes about 8,500 cases of construction accidents that occurred over the past 10 years and identified risk factor by construction industry sector to secure a systematic insight for risk management. Based on interrelation analysis between accident types, work types, original cause materials and assailing materials, there is correlation between each analysis factor and work industry. Especially for work types, there is great correlation between work tasks and industry type. For reinforced concrete and earthwork are among the most frequent types of accidents, and they are not only high in frequency of accidents, but also have a high risk in categories of occurrence.