• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.4
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• pp.70-82
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• 2007

Aiming at nature's early restoring needs to select plant species harmonizing with surrounding environment that fits to restoring goal of ultimately aiming at woody plants dominant vegetation that protect and stabilize surface parts of bared slopes. And it is important to make it assimilated with surrounding natural vegetation by differentiating planning of seed mixtures. Natural Ecological Restoring Construction Methods (JSB Method) was developed to increase the effect of landscape change according to seasons not to simple hydro-seeding by reducing rate of foreign grasses while raising rate of wild flower using. It was considered that using wild flowers that bloom on each season solved the problems of slope landscapes that looks artificial and uninteresting. After researching environmental condition of the slopes, JSB Method has shown that, as of wet-type method, soil is relatively soft and the difference of thickness of plant base soil media affects on the difference of soil hardness. In case of soil hardness of 8.8~17mm, there's dangerousness of slope's collapsing, but it has shown that growth of plant was favorable. For the acidity of soil, most of them are in the type of neutralized soil of more than pH 6. And after analyzing the degree of woody plants dominance, it had shown that lower part was occupied with wild flowers and other herbaceous species like China pin, golden phesant mum, pitcher plant, and middle and upper part was occupied with woody plants like silk-tree, sumac forming multi-layer structure. It can be concluded that the restoration objects of the woody plant vegetation on the roadside slopes can be accomplished successfully by Natural Ecological Restoring Construction Method (JSB method).

• Journal of Korean Clinical Health Science
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• v.1 no.1
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• pp.35-45
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• 2013

Purpose. Based on the comparison and analysis with those of United States, the aim of this research is to find the problems in current management, operation and future directions of emergency medical service (EMS) fund in S. Korea and to provide basic resources and appropriate measures to make a right decision in policies for EMS fund. Methods. Data from Ministry of Health and Welfare and other various sources during 1995 to 2012 were collected and analyzed. Results. From our analyses, several problems are identified in EMS fund operation. In brief, problems discerned are as follows. First, whereas the purpose and direction of EMS fund operations in United States are highlighted and focused on pre-hospital EMS system and associated infrastructures which need to be constructed, those of S. Korea are emphasized mainly on the in-hospital EMS system so far. Second, on the contrary to the fact that the EMS funds in United States are tuned to pre-hospital EMS system to provide prompt and efficient emergency care at the emergency scene of pre-hospital stage and to achieve the development, design, planning and demonstration projects for pre-hospital EMS systems, up to date, our investment of EMS funds demonstrated an excess biased inclination toward the construction of in-hospital EMS system, which is far from the realization of constructive and vital pre-hospital infrastructures. Third, while emergency medical technician is important and principal body in the management of emergency medical funds in United States, so far, no EMS funds in S. Korea existed for EMTs including the job condition, improved treatment and working environment for them. Conclusion. In conclusion, we strongly suggest that the problems pointed out must be revised and corrected. Current usage of EMS fund needs to be redirected predominatly to pre-hospital EMS system. Otherwise, unless current management and investment of emergency medical funds in S. Korea are applied and used for the vital necessities and demands of EMTs, public EMS units and private EMS units as well as related units in pre-hospital EMS system as in the cases of United States, in our consideration, they must be suspended or abolished.

• Journal of Korean Society of Forest Science
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• v.31 no.1
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• pp.48-52
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• 1976

In order to investigate the effects of seed weight, size (length and thickness), and maturation period (early maturing seed or late maturing seed) on growth of first-year seedlings in Pinus koraiensis, pot cultivation experiment with seeds collected from Gangweon University Forest was carried out under relatively controlled environment condition. At the end of one growing season, not only fresh weight, length, diameter (at underside of cotyledon) and root length of seedlings, but also number and length of cotyledon were measured. Results are as follows; 1. Germination percentage is independent of weight and size of seeds, but it was influenced by maturation period, that is, late maturing seeds surpass early maturing one in germination percentage. 2. Germination percentage is affected by maturation period of seeds in 18.3% of contribution rate. 3. Each growth of first-year seedlings is influenced considerably by the differences of weight, length and thickness of seeds, that is, heavy and large seeds produce larger seedlings than do light and small seeds. Particularly, fresh weight, diameter, length of cotyledon are significantly affected by differences of seed weight and size (length and thickness) in 50-90% of contribution rate. 4. Differences of seed weight and thickness have a tendency to affect more on growth of first-year seedlings than do differences of seed length. 5. Seedlings from late maturing seeds are superior than those from early maturing one in fresh weight, diameter of seedlings and length of cotyledon, but it's influence is a little.

• Journal of the Korean Society for Railway
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• v.15 no.6
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• pp.579-587
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• 2012

Shin-gumho station in Seoul underground subway have been selected to be experimentally investigated and analyzed for the real air supply & exhaust capacity compared to the original capacity of ordinary and emergency condition. The depth of Shin-gumho station is 43.6m which consists of the island-type platform ($8^{th}$ floor in underground) and a two-story lobby (first & second floor in underground). An emergency staircase connects between the platform and the lobby. Hot-wire anemometer, capture hood, wind vane & velocity meter and data acquisition systems are employed to perform the automatic measurement in this experiment. For ordinary case, air supply and exhaust capacity in the lobby were reduced by 34% and 46% compared to the original capacity, respectively. Air supply and exhaust capacity in the platform were reduced by 66% and 38%, respectively. For emergency case, air supply in the lobby was reduced by 42% and air exhaust in the platform was reduced by 28% compared to the original capacity. Therefore, air pollution in the station is expected to be worse in the ordinary environment and smoke control capability in the platform will be weakened in case of fire emergency.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.4
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• pp.77-91
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• 2011

This study tries to find a streambed scouring and sedimentation characteristics through the Rosgen(1994)'s stream classification system while experiencing several flood events. The Jinwee and Osan streams, the tributaries of Anseongcheon were selected. The streams showed type C or type E. By the classification results, two Type C tributaries one Type C stream and one Type E tributary were selected. For the four selected stream reaches, the analysis of streambed change was implemented by using numerical model CCHE2D (Center for Computational Hydroscience and Engineering). To prepare the inlet boundary conditions of each stream, the WMS (Watershed Modeling System) HEC-1 was used and the streamflows of 50, 80, and 100-year return period were generated and the outlet boundary was set to an open boundary condition. The simulation results showed that when the flood pulse periodically the streambed changes also appears regularly. The results can be used to acquire the basic data for stream restoration.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.4
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• pp.91-100
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• 2010

Existing traffic safety studies have focused on identifying the relationship among roadway crashes, highway design and incremental weather condition such as rainy/ice weather. However, it is hard to find researches that studied the effect of sun glare on traffic safety although there are abundant evidences demonstrating that fatal traffic crashes are attributed to the sun glare. Affecting drivers'vision particularly during the morning or the evening time when the sun positions close to the horizon, sun glare directly deteriorate drivers'judgmental capability. In this paper, we numerically analyze the effect of sun glare on the drivers'vision in time and space domains. Applied to the roadways around St Louis area in the United States, the GIS based simulation analysis identifies the time of day in a year and the segments of highways that are potentially influenced by the sun glare. This study evidentially confirms the fact that roadway bounded for West and East directions have longer time influenced by sun glare particularly during Spring and Fall season than other roadways. The computational result provides risky time periods of day at intersections or pedestrian crossings where the sun glare potentially endangers traffic safety, which be utilized to reduce the crashes due to the sun glare.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.2
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• pp.105-115
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• 2011

User authentication service is an absolutely necessary condition while securely implementing an IT service system. It allows for valid users to securely log-in the system and even to access valid resources from database. For efficiently and securely authenticating users, smart-card has been used as a popular tool because of its convenience and popularity. Furthermore the smart-card can maintain its own power for computation and storage, which makes it easier to be used in all types of authenticating environment that usually needs temporary storage and additional computation for authenticating users and server. First, in 1981, Lamport has designed an authentication service protocol based on user's smart-card. However it has been criticized in aspects of efficiency and security because it uses hash chains and the revealment of server's secret values are not considered. Over the years, many smart-card based authentication service protocol have been designed. Very recently, Xu, Zhu, Feng have suggested a provable and secure smart-card based authentication protocol. In this paper, first, we define all types of attacks in the smart-card based authentication service. According to the defined attacks, however, the protocol by Xu, Zhu, Feng is weak against an attack that an attacker with secret values of server is able to impersonate a valid user without knowing password and secret values of user. An efficient and secure countermeasure is suggested, then the security is analyzed.

• Korean Journal of Ichthyology
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• v.27 no.1
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• pp.21-25
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• 2015

We studied the effects of temperature and salinity on the egg development and larvae of sevenband grouper Epinephelus septemfasciatus under sea cage culturing condition. In regard to rearing environment, the water temperature is $21.5{\sim}23.5^{\circ}C$ (mean $22.0{\pm}0.05^{\circ}C$) and the salinity is 32.0~33.0 psu (mean $32.5{\pm}0.05psu$). The time of egg development was positively proportional to water temperature with 29 hrs, 27 hrs, 24 hrs, 17 hrs, 15 hrs after fertilization in $15^{\circ}C$, $20^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$, $35^{\circ}C$ respectively. Each of the salinity hatching rate was 80% in the section of 15 psu, 81.8% in the section of 25 psu, 89.1% in the section of 30 psu, and 79.1% in the section of 35 psu. All things considered, the highest hatching rate appeared in the range of the section of 25~30 psu. Abnormalities of low salinity section, such as 15 psu (20.0%) and 20 psu (18.2%), was lower than the abnormalities of 35 psu that belongs to high salt section. The relation between the time of egg development (t:hour) and water temperature ($T:^{\circ}C$) was represented by the mathematical formulae. The mean biological minimum temperature was $5.4^{\circ}C$.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.3
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• pp.52-61
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• 2020

This study developed a legibility distance(LD) model for three colors used in VMS according to luminance under foggy conditions through experiments. For this, a simulated environment was created, and LD values of red, green, and yellow color were collected by increasing the luminance. From the test results, the LDs for red at luminance levels of 2,000 cd/㎡ and 20,000 cd/㎡ and a visibility distance of 10m were 10.2m and 18.8m, respectively, which was an improvement of 84%. The LD was improved by 34% and 17% at a visibility distance of 20 m and 30 m, respectively. For green, the LD was improved by 69%, 63%, and 19% at visibility distance of 10m, 20m, 30m, respectively. For yellow, the LD was improved by 100%, 47%, and 36% at visibility distance of 10m, 20m, 30m, respectively. The LD models for three colors were developed by using two independent variables, luminance value and visibility distance. The adjusted coefficients of the red, green, and yellow model equations were calculated as 0.982, 0.978, and 0.915, respectively, and the explanatory power of all models was very high.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.2
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• pp.82-86
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• 2011

Lightweight aggregate which is composed of sintered polycrystalline materials usually has a certain portion of pores inside of it. Because of such a structural characteristics, it tends to that movement of water in aggregate shows an abnormal behavior against the change of outside environment. In general, water movement behavior is controlled by porosity, distribution of pore size; however, dense surface layer will also affect water movement behavior in case of artificially sintered aggregates. Factors affecting water movement behavior in the aggregate are pore distribution, pore shape, pre-wetting method, etc. In this study, absorption characteristics of aggregate under the pressure and absorption rate according to water dipping time are analyzed for the basis of pressure pumping of lightweight concrete. Two kinds of aggregates were used for the test: one is made by 'L' company in Germany and the other is of our own made at the pilot plant in Kyonggi University. Absorption rate of aggregate is measured according to water dipping time, vacuum pressure, and quenching condition. Absorption rate of aggregate with $300^{\circ}C$ quenching is higher than that of aggregate with 24 hr water dipping. Generally the more vacuum the higher water absorption rate. Water absorption rate of 'L' aggregate under -300 mmHg is 54 % higher than that of aggregate with 24 hr water dipping; however, only 2 % increase in water absorption was measured for the K622 and K73 which were of our own.