• Journal of the Korea Society of Computer and Information
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• v.20 no.6
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• pp.59-76
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• 2015

Recent wide spread of embedded devices and technology growth of broadband communication has led to rapid increase in the volume of created and managed data. As a result, data centers have to increase the storage capacity cost-effectively to store the created data. Data deduplication is one way to save the storage space by removing redundant data. This work propose IO extent based deduplication schemes called CORE-Dedup that exploits content-preserving access locality. We acquire IO traces from block device layer in virtual machine host, and compare the deduplication performance of chunking method between the fixed size and IO extent based. At multiple workload of 10 user's compile in virtual machine environment, the result shows that 4 KB fixed size chunking and IO extent based chunking use chunk index 14500 and 1700, respectively. The deduplication rate account for 60.4% and 57.6% on fixed size and IO extent chunking, respectively.

• Korean Journal of Agricultural and Forest Meteorology
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• v.1 no.1
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• pp.12-19
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• 1999

CERES-rice, a rice growth simulation model, was used in conjunction with daily weather data to figure out the spatial variation of the phenology and yields of paddy rice at 168 rice cultivation zone units(CZU) of Kyunggi Province in 1997. Two sets of cultivar specific coefficients, which represent early and mid-season maturing varieties, were derived from field experiments conducted at two crop experiment stations. The minimum data set to run the model for each CZU (daily maximum and minimum temperature, solar irradiance, and rainfall) was obtained by spatial averaging of existing 'Digital Map of Korean Climate'(Shin et al., 1999). Soil characteristics and management information at each CZU were available from the Rural Development Administration. According to a preliminary test using 5 to 9 years field data, trends of the phasic development(heading and physiological maturity), which were obtained from the model adjusted for these coefficients, were in good agreement with the observed data. However, the simulated inter-annual variation was somewhat greater than the reported variation. Rough rice yields of the early maturing cultivar calculated by the model were comparable with the reported data in terms of both absolute value and inter -annual variation. But those of the mid season cultivar showed overestimation. After running the simulation model runs with 1997 weather data for 168 CZU's, rough rice yields of the 168 CZU's calculated by the model were aggregated into corresponding 33 counties by acreage-weighting to facilitate direct comparison with the reported statistics from the Ministry of Agriculture and Forestry. The simulation results were good at 22 out of the 26 counties with reportedly increasing yield trend with respect to the past 9 years average.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.3
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• pp.39-49
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• 2017

Standards suitable for local conditions on deciding one-way road are desperately required to solve traffic congestions at the backside roads in the old downtown areas which were not designated as a road by urban planning. Therefore, this study intends to re-establish a standard to decide one-way road which is regarded to be of the greatest effect among traffic system control methods in order to control one-way road system more efficiently. Also, this paper suggests a standard for such decision to improve efficiency of using backside roads and expand designation of one-way road. AHP (analytic hierarchy process) was carried out among the traffic experts to find out the factors to decide one-way road system. Its result reveals that importance of causing accident to walking quantity and traffic was high. 10,000 cases out of all the possible scenarios of accident by combining detailed evaluation items and scales were extracted to draw the outcomes of analyzing the scenarios, which were schematized in a graph. As a result, division by three sections of point of inflection was verified into $1{\leq}$ section A<1.91, 1.9$1{\leq}$ section B<2.08, and $2.08{\leq}$ section C<3. In other words, priority of deciding one-way road should be given to section C, the highest total point, while posterior to section A, where relatively low points are distributed. The standard on deciding one-way road suggested in this paper may be used for designating one-way road and basic data to re-establish the relevant system in the future.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.5
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• pp.97-105
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• 2020

Recently, for a smart city, there is a demand for a technology for acquiring traffic information using an intelligent road infrastructure and managing it. In the meantime, various technologies such as loop detectors, ultrasonic detectors, and image detectors have been used to analyze road traffic information but these have difficulty in collecting various informations, such as traffic density and length of a queue required for building a traffic information DB for moving vehicles. Therefore, in this paper, assuming a smart city built on the basis of a camera infrastructure such as intelligent CCTV on the road, a solution for calculating the traffic DB of moving vehicles using Vision Tracking of road CCTV cameras is presented. Simulation and verification of basic performance were conducted and solution can be usefully utilized in related fields as a new intelligent traffic DB calculation solution that reflects the environment of road-mounted CCTV cameras and moving vehicles in a variable smart city road environment. It is expected to be there.

• Journal of the Korea Institute of Building Construction
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• v.20 no.5
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• pp.471-480
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• 2020

Although the domestic industrial accidents have been decreased gradually, deaths in the construction sites have been occupied 49.9 percent of the total industry and deaths from fall accident have been accounted for 59.7 percent of the construction industry. In order to prevent fall accident, various safety activities and policy have been carried out. However, the impact on the domestic construction industry was inadequate. On the other hand, in advanced countries, such as the United States, Japan, EU, and Singapore Industrial accidents have been lower than domestic industry due to safety activities, the regulations and policies appropriate for each country's situation. In this study, we compare the major points of the Industrial Safety and Health Act in developed countries with those in South Korea to reduce the number of falls, and propose a revision. As a result of conducting research, three revisions have been proposed as 1) Enhance standards for fall height, 2) Improvement of upper safety rail height on guardrail, 3) Revision and research on Horizontal Sarety bar attachment system. This study will be utilized as a basic study for the analysis of cases in advanced countries.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.821-831
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• 2013

As a result of recent research, it is reported that the periodic replacements criterion of rails is able to extend as grinding rail surface and using the continuous welded rail (CWR). In this study, we carried out fatigue tests on existing laid rails. Based on the test results, an S-N curve expressing the remaining life of laid rails at a fracture probability of 50% was obtained using weighted probit analysis suitable for small-sample fatigue data sets. As rails used for testing had different histories in terms of accumulated tonnage, the test data were corrected to average out the accumulated tonnage. We estimated the remaining service lives for laid rails on the urban railway using equations developed in the past to estimate rail base bending stress and that surface irregularities into consideration. Therefore, estimating the remaining service life of laid rails showed that the rail replacement period could be extended over 200 MGT, although it is necessary to remove longitudinal rail surface irregularities at welds by grinding. Also, the fatigue test results under fatigue limit, Haibach's rule appling half slope of S-N curve under the fatigue limit was considered more reasonable than modified Miner's rule for estimating rail fatigue life.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.29-41
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• 2017

Design rainfalls are one of the most important hydrologic data for river management, hydraulic structure design and risk analysis. The design rainfalls are first estimated by a point frequency analysis and the IDF (intensity-duration-frequency) curve is then constructed by a nonlinear regression to either interpolate or extrapolate the design rainfalls for other durations which are not used in the frequency analysis. It has been widely recognised that the more reliable approaches are required to better account for uncertainties associated with the model parameters under circumstances where limited hydrologic data are available for the watershed of interest. For these reasons, this study developed a hierarchical Bayesian based GLM (generalized linear model) for a regional frequency analysis in conjunction with a scaling function of the parameters in probability distribution. The proposed model provided a reliable estimation of a set of parameters for each individual station, as well as offered a regional estimate of the parameters, which allow us to have a regional IDF curve. Overall, we expected the proposed model can be used for different aspects of water resources planning at various stages and in addition for the ungaged basin.

• Journal of the Korean Society for Railway
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• v.18 no.2
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• pp.139-148
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• 2015

By increasing the vertical stiffness of the rail fastening system, the dynamic wheel load of the vehicle can be increased on the ballast track, though this increases the cost of track maintenance. On the other hand, the resistance acting on the wheel is decreased, which lowers the cost of the electric power to run the train. For this reason, the determination of the optimal fastener stiffness is important when attempting to minimize the economic costs associated with both track maintenance and energy to operate the train. In this study, a numerical method for evaluating the optimal vertical stiffness of the fasteners used on ballast track is presented on the basis of the process proposed by L$\acute{o}$pez-Pita et al. They used an approximation formula while calculating the dynamic wheel load. The evaluated fastener stiffness is mainly affected by the calculated dynamic wheel load. In this study, the dynamic wheel load is more precisely evaluated with an advanced vehicle-track interaction model. An appropriate range of the stiffness of the fastener applicable to the design of ballast track along domestic high-speed lines is proposed.

• Korean Journal of Environment and Ecology
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• v.25 no.4
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• pp.581-589
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• 2011

The purpose of this study is to investigate the structure of vegetation dominated by deciduous broad-leaved trees at the Beomeosa(Temple) Valley of Mt. Kumjungsan in Busan. To this end, 28 plots were set up and surveyed. The result analyzed by TWINSPAN, one of the classification technique, showed that the communities were divided into six groups which are Carpinus tschonoskii-Deciduous broad-leaved forest community(I), Quercus serrata-C. tschonoskii community(II), C. tschonoskii-Q.s serrata-Pinus densiflora community(III), C. tschonoskii-Quercus serrata-Q. mongolica communtiy(IV), Q. serrata-Deciduous broadleaved forest community(V) and Chamaecyparis obtusa-C. tschonoskii community (VI). Species diversity ranged from 0.3832 to 0.0450. The lowest diversity was Chamaecyparis obtusa community(VI) but the highest was Carpinus tschonoskii-Deciduous broad-leaved forest community(I) and Q. serrata-Deciduous broadleaved forest community(V). The average number of species was 6.8${\pm}$3.2 in the unit area(100$m^2$). Carpinus tschonoskii community at the Beomeosa Valley of Mt. Geumjeongsan was a climatic climax forest having a value to preserve, so a continuous management will be needed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.5
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• pp.335-342
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• 2013

Since the seriousness of environmental pollution came to the fore recently, various efforts have been made globally for the reduction of the environmental load. In particular, in the field of construction, an industry responsible for a considerable amount of pollution, studies have been actively conducted to reduce $CO_2$ emissions and energy consumption. However, most conventional research about pollution as it relates to construction is focused on the maintenance stages where $CO_2$ emissions are the greatest. Research related to the design stage is in its infancy, as it has only been conducted thus far on steel buildings and RC buildings. In fact, in order to achieve environmentally friendly construction considering the Life Cycle Assessment(LCA), the building design should be derived to reduce the $CO_2$ emissions from the early building design stage, and structural engineers should be able to suggest a design plan considering its environmental friendliness. In this study, optimal structural design method for steel reinforced concrete(SRC) columns considering $CO_2$ emissions is presented. The trends of $CO_2$ emissions in SRC columns according to the variations of steel shapes, concrete strengths and loads are investigated.