• Journal of Korea Water Resources Association
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• v.39 no.4 s.165
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• pp.335-346
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• 2006

Among various input data to hydrologic models, rainfall measurements arguably have the most critical influence on the performance of hydrologic model. Traditionally, hydrologic models have relied on point gauge measurements to provide the area-averaged rainfall information. However, rainfall estimates from gauges become inadequate due to their poor representation of areal rainfall, especially in situations with sparse gauge network. Alternatively, radar that covers much larger areas has become an attractive instrument for providing area- averaged precipitation information. Despite of the limitation of the QPE(Quantitative Precipitation Estimation) using radar, we can get the better information of spatial variability of rainfall fields. Also, rain-gauges give us the better quantitative information of rainfall field. Therefore, in this study, we developed improved methodologies tu estimate rainfall fields using an ordinary cokriging technique which optimally merges radar reflectivity data into rain-gauges data.

• Nano
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• v.13 no.10
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• pp.1850113.1-1850113.11
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• 2018

Environmental and energy issues have always been a hot topic of global research. Oil leakage has caused great damage to the environment, affecting a wide area and it is difficult to clean up. In most cases, carbon-based adsorbents are typically utilized to remove oil spills because of their economic benefits and high adsorbent efficiency. At the same time, its excellent material properties can also be used for the preparation of supercapacitors. In this paper, the carbon aerogels were prepared by the one-step method. The prepared materials endowed a 3D network structure with a huge number of micropores and mesoporous, and the material is light-weight, stable, hydrophobic and has affinity for oil (17.02 g/g) to the KGM carbon aerogel. Through the physicchemical characterization, the KGM carbon aerogel shows specific surface area is $689m^2/g$, high water contact angle ($136.64^{\circ}$) and excellent reusability (more than 15 cycle times). In addition, we also discussed the electrochemical properties of the material and obtained the specific electrical capacity of 139 F/g under the condition of 1 A/g.

• Journal of Korea Water Resources Association
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• v.50 no.1
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• pp.29-35
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• 2017

A vehicle rainfall sensor is made to control the operating speed of wipers depending on rainfall. Therefore this is the apparatus to determine the velocity phase of the wipers roughly based on the amount of rainfall. However, the technology which can judge the size of rainfall amount besides determining speed level of the wipers is developing according to the development of the function of rainfall sensor due to the development of technology. In this study, a rainfall measurement by using light scattering by precipitation particles was used. This measurement is to use light signal reflection from front glass and the bigger particle is the less detection of light by light scattering. The detection area of the rainfall sensor and detection channel were extended sizes to increase the accuracy of the rainfall. Also the W-S-R relational expression was developed by using a relationship between the specific precipitation (R) and the amount of sensor detection (S) when there is speed change of the wipers (W) and an indoor rainfall apparatus was used to convert sensing signal to rainfall. The signal system of vehicle rainfall sensor can be converted to the actual rainfall amount by using this formula and if this is provided to users then the vehicle observation network can produce higher-resolution than actual observation network can be produced.

• Journal of the Korean GEO-environmental Society
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• v.2 no.1
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• pp.37-56
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• 2001

As a preliminary study to establish fracture network model in crystalline rocks, detail investigation on fracture characteristics were performed. Five fracture sets were determined on the basis of regional survey of geological structures and fractures on outcrops. Among the fracture sets, S1 set has the highest density and longest trace length of fractures which was identified on surface in the study area. S4 and S5 sets are composed of foliations and foliation parallel shear joints of gneisses, which are very important sets at the aspect of weighting of fracture length. For characterization of subsurface fractures, detail core logging was performed to identify fractures and fracture zones from five boreholes. Acoustic televiewer logging and borehole geophysical loggings produced images, orientations and geophysical properties of fractures which intersect with boreholes. According to the result of the investigations, subsurface fractures can be grouped as three preferred orientations(B1, B2 and B3), which correspond to S1, S2 and S4/S5 of surface fracture sets, respectively. Actually, B1 set is expected to be intensely developed at subsurface. However, it has low frequency of intersection with boreholes due to its parallel or sub-parallel direction to boreholes. According to the inference of conductive fractures, B1 and B3 sets have possibilities of water flow and their intersection lines are also thought to consist of important conduits of groundwater flow. In particular, faults which are parallel to foliations control major groundwater flow in the study area.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.3
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• pp.185-200
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• 2021

The Marine Environment QA/QC management system has been operated since 2010 to secure the reliability of data and improve the analysis capabilities of measurement and analysis institutions. From 2010 to 2020, the cumulative number of measurement and analysis institutions participated in the QA/QC management system was 266. And the number of certificates issued by the ministry of oceans and fisheries is 182. A total of 32 reference materials for proficiency testing and interlaboratory comparisons have been developed. They were first developed focusing on items (Nutrients, COD) commonly analyzed in marine environmental measuring network, marine pollution impact surveys, sea area utilization impact assessment, deepsea water surveys, and information network on fishing ground environments. In addition, it is time to expand the filed of the QA/QC management system, such as seawater temperature, salinity, PCBs and PAHs in sediments, which are mainly analyzed in most monitoring programs. On-site assessment has been conducted for 162 laboratories according to ISO/IEC 17025 to evaluate their conformity of the quality management system and deficiency. In terms of management and technology requirements, about 4.2% of organizations showed insufficient division of duties among employees 8.7% of them revealed the lack of employee training. By test item, about 6.3% of organizations showed the lack of standard substance management and the state of the cleaning glassware was pointed out in about 5.4% of them. The QA/QC management system should be continuously supplemented by identifying the causes of nonconformities and area for improvement.

• Journal of International Area Studies (JIAS)
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• v.15 no.1
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• pp.83-108
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• 2011

South America has vast energy resources with the renewable and non-renewable sources. However, many countries in the region are unable to guarantee adequate energy security both of energy supply and demand. Currently the possibility of energy security is high through regional energy integration based on the potential economic benefits. The difference of regulation system with the individual countries in the region impose strong barriers to integration process. Security of energy supply and its demand as well is fundamental issues in this region and regional energy cooperation is essential for getting rid of the insecurity of energy supplies. Despite of this problem, currently Latin American countries made a great effort to make multilateral energy security regime through projecting great energy infrastructure network(e.g. IIRSA) or mechanism especially in South America, which can give countries access to the region's reserve supplies by providing regulations and pricing mechanism with a shared energy market in this region. Brazil's active leading in the formulation of such movement toward energy security integration and participation of energy infrastructure network is good initiative to enforce this great energy security change. Politically and economically, Brazil's geographical position and the level of market size and oil and natural gas resources, in addition the leadership in renewable energy sources make it a sound candidate to take over the coordination of the secure integration of region's energy market. However, on the conditions of existing many obstacles such as, control of the output of the region's power plant, energy flows, the environmental matter within local community must be overcome to make more advance process and steps. Finally, to secure more institutional approach, this region must settle regional disputes resolution regime urgently.

• The KIPS Transactions:PartC
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• v.12C no.4 s.100
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• pp.571-580
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• 2005

In fast long-distance networks, TCP's congestion control algorithm has the problem of utilizing bandwidth effectively. Several window-based congestion control protocols for high-speed and large delay networks have been proposed to solve this problem. These protocols deliberate mainly three properties : scalability, TCP-friendliness, and RTT-fairness. These protocols, however, cannot satisfy above three properties at the same time because of the trade-off among them This paper presents a new window-based congestion control algorithm, called EM (Exponential Increase/ Multiplicative Decrease), that simultaneously supports all four properties including fast convergence, which is another important constraint for fast long-distance networks; it can support scalability by increasing congestion window exponentially proportional to the time elapsed since a packet loss; it can support RTT-fairness and TCP-friendliness by considering RTT in its response function; it can support last fair-share convergence by increasing congestion window inversely proportional to the congestion window just before packet loss. We evaluate the performance of EIMD and other algorithms by extensive computer simulations.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.1
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• pp.1-5
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• 2010

Recently emphasizing the importance of security such as national major institutions' facilities or major industrial facilities for the maintenance of security/crime prevention due to specialization of the Green Information Technology(G-IT) and Green Ubiquitous Technology(G-UT) industry fields, The Security System Building linked high technology within the government-related organization, enterprise and army the military is urgently required. This paper is about the green USN intelligent an unmanned guard MUX system that receive the signals, from alarm device within surveillance area, with various ways of communication techniques and then transmit to local control center and remote control server trough TCP/IP network. This study enables the mutual senergy effect by realizing a total solution of an unmanned guard system and also significantly contributes to the global/domestic market expansion. That can be applied to the crime prevention/security fields in the Green Ubiquitous Environment Implemented Business(survalance-Home, Gu-City, Gu-Health, etc.), and will contribute to expand companies with international competitiveness that can provide the Green Ubiquitous Vision(Gu-Vision).

• Journal of the Korean association of regional geographers
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• v.13 no.5
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• pp.495-508
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• 2007

This study pays attention to the organization of local-level farming group, which has been recognized as a solution to the problems of agriculture and rural area with their crisis deepened by the coming of FTA. More specifically, this study analyzed each farming household's understanding of the farming group organization of fruit nursery tree growing region, and their participational behavior types. As a result, it is revealed that the organization of farming group oriented to enhance its competence must aim to realize its economic benefits rather than to maintain the social relationship among the members of organization. Also it has to orient itself not to abstract causes but to more concrete and practical objects. In addition, the farming group must be organized based on the identity of growing farm product, and in respect of the reliability among the members, there must be a proper level of control that makes the internal control and the harmonious interaction among the members to be possible.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.6
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• pp.620-627
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• 2004

As h-bridge multilevel inverter is connected with series of single phase power cell, so it obtain high voltage using low voltage power semi-conductor and output voltage similar to sine wave. In this topology, the number of power cell increases in proportion to the output voltage level. Therefore, there are drawbacks that are responsibility against operating ability of main controller and signal wire increase. However, we can overcome this problems by the substitution of serial communication for the PWM signal in power cell control. Additionally, it has merits of reliability and maintenance. This paper deals with the synchronization and phase-shift method of power cell PWM using CAN(Controller Area Network) communication interrupt in H-bridge multilevel inverter. The advantages of proposed method are signal-line simplification using serial communication between main controller and cell controller, burden reduction in main controller, modularization of power cell, easy protection of each power cell, expandability improvement and reliability increase of control signal and power cell. This paper establishes propriety and reliability of proposed method through experiment of 13-level H-bridge multilevel inverter.