• Journal of Korean Society on Water Environment
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• v.29 no.2
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• pp.247-258
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• 2013

A grid-based configuration of Land Surface Models (LSMs) coupled with a climate model can be advantageous in impact assessment of climate change for a large scale area. We assessed the applicability of Common Land Model (CoLM) to runoff and land surface temperature (LST) simulations at the domain that encompasses the Nakdong river basin. To establish a high resolution model configuration of a $1km{\times}1km$ grid size, both surface boundary condition and atmospheric inputs from the observed weather data in 2009 were adjusted to the same resolution. The Leaf Area Index (LAI) was collected from MODerate esolution Imaging Spectroradiometer (MODIS) and the downward short wave flux was produced by a nonstationary multi-site weather state model. Compared with the observed runoffs at the stations on Nakdong river, simulated runoffs properly responded to rainfall. The spatial features and the seasonal variations of the domain fairly well were captured in the simulated LSTs as well. The monthly and seasonal trend of LST were described well compared to the observations, however, the monthly averaged simulated LST exceeded the observed up to $2^{\circ}C$ at the 24 stations. From the results of our study, it is shown that high resolution LSMs can be used to evaluate not only quantity but also quality of water resources as it can capture the geographical features of the area of interest and its rainfall-runoff response.

• Water for future
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• v.28 no.5
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• pp.219-233
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• 1995

A non-stationary multivariate model is selected in which the mean and variance of rainfall are not temporally or spatially constant. And the rainfall prediction system is constructed which uses the recursive estimation algorithm, Kalman filter, to estimate system states and parameters of rainfall model simulataneously. The on-line, real-time, multivariate short-term, rainfall prediction for multi-stations and lead-times is carried out through the estimation of non-stationary mean and variance by the storm counter method, the normalized residual covariance and rainfall speed. The results of rainfall prediction system model agree with those generated by non-stationary multivariate model. The longer the lead time is, the larger the root mean square error becomes and the further the model efficiency decreases form 1. Thus, the accuracy of the rainfall prediction decreases as the lead time gets longer. Also it shows that the mean obtained by storm counter method constitutes the most significant part of the rainfall structure.

• Water for future
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• v.7 no.2
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• pp.11-22
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• 1974

Comparing with Seoul city's other administrative works, the work to arrange and collect monthly water rates with 470,000 faucets is tremendous in volume and simple repetition in quality. In order to cover the shortage of handling, it is urgent for us to replace the present manual system with EDP(Electronic Data Processing) system to mechanize a series of handling works of simple repeated calculation such as water consumption, rate calculation, statistics arrangement, bills and specification of water rate by computer. When this work is completely mechanized, inspectors of water meter just turn over their checking results to the Data Center and all data are processed through Input Media(OMR Card, Punched Card) and computer for programming final bills. Then, the delivery of the bills to citizens will be the only work to be carried out. such mechanization will bring about the following benefits: 1. Improvement of administrative work by efficiency and rationalization. 2. Improvement of administrative service with people. 3. Possibility of scientific with trustworthy multi-purpose policy-making data. 4. An effect to cover the personnel shortage of 252 persons (at all the water works offices) and save manpower of 166 persons (47,619 man-days). The application of the above mentioned mechanization will be started to only Chongro and Chung-ku water works offices as model cases out of all water works offices in Seoul. As the electronic calculating machines are inducted, this system will be gradually applied to other water works offices. The billing and collection works of water rates which are connected directly to the daily life of the citizenes, should be handled by the scientific EDP system as soon as possible in order to promote the convenience of consumers and effective operation. This study is to promote the sound and rational operation of this work.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.5
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• pp.133-142
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• 2004

Recently, the growth of Internet and a variety of multimedia services through Internet increasingly demands high-speed packet transmission, the new routing function, and QoS guarantee on conventional routers. Thus, a new switching mechanical called the MPLS(Multi-Protocol Label Switching), was proposed by IETF(Internet Engineering Task Force) as a solution to meet these demands. In addition the deployment of MPLS network supporting Differentiated Services is required. In this paper, we propose the architecture of the MPLS switch supporting Differentiated Services in the MPLS-based network. The traffic conditioner consists of a classifier, a meter, and a marker. The VOQ-PHB module, which combines input Queue with each PHB queue, is implemented to utilize the resources efficiently. It employs the Priority-iSLIP scheduling algorithm to support high-speed switching. We have designed and verified the new and fast hardware architecture of VOQ-PHB and the traffic conditioner for QoS and high-speed switching using NS-2 simulator. In addition, the proposed architecture is modeled in VHDL, synthesized and verified by the VSS analyzer from SYNOPSYS. Finally, to justify the validity of the hardware architecture, the proposed architecture is placed and routed using Apollo tool.

• The Transactions of the Korea Information Processing Society
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• v.4 no.1
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• pp.76-86
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• 1997

Many information retrieval systems have a simple process structure that a client process for a user is mapped to a server process for information retrieval. That is, when using information retrieval systems, each user is allocated a big process that consists of user interfaces, retrieval automatic indexing systems and storage systems. Therefor when many users use the information retrieval systems, it might be difficult to use the information retrieval systems. This is because the system overhead is increased as enormously much as users cannot use them. In this paper, we propose a new process structure for constructing efficient information retrieval systems that solves the problem resulting from he process structure. The proposed process structure contributes to the whole operational performance improvement of information retrieval systems and the efficientnt use of computer system resources. It is constructed based on a multi-threading scheme and a transaction processing monitor.

• Korean Journal of Materials Research
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• v.16 no.3
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• pp.188-192
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• 2006

The microstructures and mechanical properties of continuously porous $SiC-Si_3N_4$composites fabricated by multi-pass extrusion were investigated at different Si levels added. Si-powder with different weight percentages (0%, 5%, 10%, 15%, 20%) was added to the SiC powder to make the raw mixture powders, with $6wt%Y_2O_3-2wt%Al_2O_3$ as sintering additives, carbon ($10-15{\mu}m$) as a pore-forming agent, ethylene vinyl acetate as a binder and stearic acid ($CH_3(CH_2)_{16}COOH$) as a lubricant. In the continuously porous $SiC-Si_3N_4$ composites, $Si_3N_4$ whiskers like the hairs of nostrils were frequently observed on the wall of the pores. In this study, the morphology of the $Si_3N_4$ whiskers was investigated with the silicon addition content. In the composites containing of 10 wt% Si, a large number of $Si_3N_4$ whiskers was found at the continuous pore regions. In the sample to which 15 wt% Si powder was added, maximum values of about 101 MPa bending strength and 57.5% relative density were obtained.

• Journal of Ocean Engineering and Technology
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• v.26 no.4
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• pp.37-41
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• 2012

Due to global warming, the need to secure alternative resources has become more important nationally. Because of the very strong current on the west coast, with a tidal range of up to 10 m, there are many suitable sites for the application of TCP (tidal current power) in Korea. In the southwest region, a strong current is created in the narrow channels between the numerous islands. A rotor is an essential component that can convert tidal current energy into rotational energy to generate electricity. The design optimization of a rotor is very important to maximize the power production. The performance of a rotor can be determined using various parameters, including the number of blades, shape, sectional size, diameter, etc. There are many offshore jetties and piers with high current velocities. Thus, a VAT (vertical axis turbine) system, which can generate power regardless of flow direction changes, could be effectively applied to cylindrical structures. A VAT system could give an advantage to a caisson-type breakwater because it allows water to circulate well. This paper introduces a multi-layer vertical axis tidal current power system. A Savonius turbine was designed, and a performance analysis was carried out using CFD. A physical model was also demonstrated in CWC, and the results are compared with CFD.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.1
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• pp.68-76
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• 2018

Target prioritization is necessary for a multifunction radar(MFR) to track an important target and manage the resources of the radar platform efficiently. In this paper, we consider an artificial neural network(ANN) model that calculates the priority of the target. Furthermore, we propose a neural network learning algorithm based on the steepest descent method, which is more suitable for target prioritization by combining the conventional gradient descent method. Several simulation results show that the proposed scheme is much more superior to the traditional neural network model from analyzing the training data accuracy and the output priority relevance of the test scenarios.

• The Korean Journal of Emergency Medical Services
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• v.7 no.1
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• pp.109-118
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• 2003

With the rapid development of information and communication technology, a lot of multi-media learning programs are being developed and reported in the field of Emergency medicine both home and abroad. In this connection, this study was aimed at developing a foreign-body airway obstruction courseware in adults for EMT. The development period of CAI courseware lasted from May 2003 through November 2003. Among CAI courseware patterns, private instruction and repeat practice and simulation patterns were used as an instruction-learning strategy. The learning contents of the CAI courseware consisted of five chapters concerning (1) A relief of partial FBAO in the responsible victim, (2) A relief of complete FBAO in the responsible victim, (3) In case of unconsciousness in the responsible victim without removing all foreign body, (4) In case of consciousness in all victims after getting removed all foreign body and (5) A complete airway obstruction in victims without consciousness on the basis of assess responsiveness and the degree of airway obstruction. The way to use this courseware, with just a click on one specific chapter, was developed to proceed a course with progressive algorithm, a method of solving problems by choosing one between two situations. A characteristic of this CAI courseware is the enhanced efficiency of an instruction-learning method by providing an opportunity of choice based on situations in its effort to encourage learners to use a self-initiated learning method, not one-way method and to enhance problem solving skills among situations. Moreover, this courseware went through the diverse phases such as development, application, feedback in connection with learning process by practicing teachers, so that the courseware could be used frequently in the future. The contents of this courseware were written with the web, so that, if necessary, the contents could be continuously modified and complemented and handed out in the form of CD-ROM. This study indicates that the development of a variety of CAI courseware requires institutional and financial assistance and initiatives reflecting a reality in terms of learning process, technical assistance and resources.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.1
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• pp.67-74
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• 2009

This paper presents a method of improving the service availability by distributing the traffic of voice/data calls over the multi-layer cells in a mobile communication network. The traffic model is described and the call handling performance is analyzed. In our method, a fast moving call is moved to and serviced in the upper layer cell. A call is also moved upward when an overflow occurs. But unlike other methods, the call that is moved upward in the overflow case is the one which has the longest sojourn time in the cell. Moreover, when the call that was moved upward due to overflow condition stays longer than a certain period of time in the upper layer cell, the system moves the call back to the lower layer in order to save the more expensive resources of the upper layer cell. Call handling performance of this method evaluated from M/M/C/K models shows clear improvement with respect to call blocking probability and forced termination probability.