• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.1
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• pp.36-44
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• 2007

This paper presented a hybrid ternary encoding scheme using 3-valued logic. It can adapt to the delay-insensitive(DI) model. We designed an asynchronous wrapper for the hybrid ternary encoding scheme to communicate with various asynchronous encoding schemes. It reduced about 50% of transmission lines and power consumption compared with the conventional 1-of-4 and ternary encoding scheme. The proposed wrappers were designed and simulated using the $0.18-{\mu}m$ standard CMOS technology. As a result, the asynchronous wrapper operated over 2 GHz communicating with a system bus. Moreover, the power dissipation of the system bus adapted the hybrid ternary encoding logic decreases 65%, 43%, and 36% of the dual-rail, 1-of-4, and ternary encoding scheme, respectively. The proposed data encoding scheme and the wrapper circuit can be useful for asynchronous high-speed and low-power asynchronous interface.

• Journal of Korean Society of Forest Science
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• v.94 no.3 s.160
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• pp.135-145
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• 2005

The purpose of this study is to reveal the component characteristics and the channels of distribution for forest products as a fuel that were consumed in Kyeongseong city (Seoul) in 1929, in the middle of the colonial period. The summary of the results are as follows; (1) though the average consumption of forest products consumed as a fuel per household in Kyeongseong city was slightly less than one-third as much forest products as fuel consumed in other counties of Kyeongki province, but due to the high heat capacity, the amount of fuelwood and charcoal consumption was much higher than leaf and grass consumption; (2) the largest supply areas of forest products for fuel were the riverside of Kangwon province and Kyeonggi province in which the waterways were available. They supplied 42.6% of total consumption, and the other supply areas were the northern part of Kyeonggi province, etc. (29.5%) where railroads were handy, and the suburbs of Kyeongseong City (27.9%) by roads; (3) the transportation areas using the Han River were divided into two parts of Ttook island (43.0%) and former Yongsan and Mapo (45.6%), but the volume of transportation by railroad was centralized in Kyeongseong Station, which accounted for 72.2% of total volume of transportation by rail; (4) the most of the forest products consumed for fuel in Kyeongseoung city were sold in temporary fuelwood markets, rather than permanent and regular markets.

• The Journal of Engineering Geology
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• v.18 no.3
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• pp.263-276
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• 2008

In diverse hydrogeologic fields, estimation of groundwater storage change is one of the most critical issues. Accurate estimation methods for determining groundwater storage change are required more and more. For Yeonyang area of Ulsan Megacity, groundwater storage change was estimated by using water balance method and hydrogeological analyses. The estimates of groundwater storage change was 240 mm corresponding to 18.7% of mean annual precipitation. Direct runoff was calculated as 137 mm (10.6% of mean annual precipitation) by using SCS-CN method. Evapotranspiration based on the Thornthwaite method was calculated as 776 mm (60.5% of mean annual precipitation). Hydraulic properties of the soil types do not show any distinct relation with hydraulic conductivity of the rocks. This fact suggests that hydraulic property on the surface is different from that of subsurface geology. According to multi-linear regression analysis between groundwater storage change and hydraulic parameters, a regression equation of groundwater storage change, which was explained by precipitation and evapotranspiration, was established.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.892-896
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• 2008

In construction work's process of a basic planning, we must carry out a topographical for construction reserved land and to the basis of this, production of profile is Indispensable factor for the purpose of every construction work such as road, rail way, canal and etc. From this research, the production of profile about construction reserved land, using topography information of numerical value topographical map produced by NGIS construction project, construct precision 3D topography model and from this, propose plans for utilizing by producing automatic profile. With the aim of this, abstract every layers of main facilities and altitude from numerical value topographical map and while producing 3D topography model by using this, we produce and product automatic profile from construct precision 3D topography. And about the produced profile's process, a topographical by mutual analysis was carried out to check whether the automatic produced profile's accuracy could be accepted at actual estimation and permissible accuracy. It is considered that the result of the research could be suggested as a new formation techniques concept which can reduce the designing time and expenses and increase the efficiency of planning in the basic design process for the construction.

• Journal of Korea Water Resources Association
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• v.40 no.1 s.174
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• pp.73-88
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• 2007

The goal of this research is to develop and apply the generalized regression neural networks model(GRNNM) embedding genetic algorithm(GA) for the estimation and calculation of the pan evaporation(PE), which is missed or ungaged and of the alfalfa reference evapotranspiration ($ET_r$), which is not measured in South Korea. Since the observed data of the alfalfa 37. using Iysimeter have not been measured for a long time in South Korea, the Penman-Monteith(PM) method is used to estimate the observed alfalfa $ET_r$. In this research, we develop the COMBINE-GRNNM-GA(Type-1) model for the calculation of the optimal PE and the alfalfa $ET_r$. The suggested COMBINE-GRNNM-GA(Type-1) model is evaluated through training, testing, and reproduction processes. The COMBINE-GRNNM-GA(Type-1) model can evaluate the suggested climatic variables and also construct the reliable data for the PE and the alfalfa $ET_r$. We think that the constructive data could be used as the reference data for irrigation and drainage networks system in South Korea.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.6
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• pp.793-799
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• 2023

This study classifies the types of urban railway stations that reflect the location characteristics of urban railway stations, the structure and form of station taxes, and the number of users, and the level of inconvenience in the transfer movement line for users by station type, the number and connectivity of transfer information, and the level of transfer convenience facilities. The number of installations, conflicts between users, and transfer information signs were analyzed. As a result of data analysis, it was found that the factors that cause the most inconvenience to urban rail users when transferring are the length and curvature of the transfer line, pedestrian density and number of passengers in the transfer passage, presence or absence of transportation convenience facilities, and the size and height of transfer information letters. These transfer inconveniences were objectified, quantified, and presented as evaluation indicators that can measure the transfer convenience of urban railway stations. Additionally, an evaluation scale was developed to measure the service level for each evaluation indicator. The evaluation scale for each indicator presented six levels by applying linear interpolation based on the maximum and minimum values of data derived through field surveys. However, it is judged that a comprehensive evaluation of transfer convenience that combines the importance and weight of each convenience evaluation indicator should be established through future research.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.2
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• pp.129-137
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• 2014

In this study, the characteristics of exhaust gas as a function of the biodiesel mixing ratio were investigated. Diesel and waste oil were used for preparing mixed fuel, and the ratios of the mixed fuel were varied in the BD3~BD100 range. The injection pressures(${\Delta}p_{inj}$) was considered as an experimental variable and was set to 400 bar, 600 bar, 800 bar, 1000 bar, and 1200 bar. Furthermore, for quantitatively analyzing the characteristics of exhaust gas(NOx and Soot), the concepts of Pearson correlation coefficient and Spearman rank-order correlation coefficient based on statistics were introduced. Consequently, it was found that the correlation of the emission of NOx and Soot is linear, and the Pearson and Spearman coefficients are -0.732 and -0.724, respectively, under all analysis conditions. Especially, for the injection pressure of 800 bar, a simultaneous reduction in NOx and Soot emission is possible by controlling the biodiesel mixing ratio. This is because the correlation coefficients of NOx and Soot emissions were nearly 0, as the Pearson correlation coefficient was -0.089.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1375-1381
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• 2011

Combustion processes in an optically-accessible single-cylinder heavy-duty diesel engine equipped with a highpressure common-rail injection system were investigated for JP-8 and diesel. Direct imaging and two-color thermometry were employed to verify the emission trend for both fuels. The combustion process was characterized by image analysis with focus on luminosity. The results of two-color thermometry were analyzed on the basis of the flame temperature and KL factor distribution. Analysis of the combustion process by direct imaging showed that the ignition delay was longer for JP-8 than for diesel, while the flame was extinguished rapidly. Analysis of the flame luminosity showed that the combustion intensity was higher for diesel and that the flame lasted for a longer duration in this case. Two-color thermometry results showed that the high-temperature region extended over a large area during JP-8 combustion, implying the formation of a large amount of $NO_x$. In addition, the KL factor showed low level over a large area and relatively homogeneous in the case of JP-8 combustion, which implied that less smoke was produced when using this fuel.

• Journal of Korean Society of Transportation
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• v.25 no.5
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• pp.15-21
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• 2007

This paper proposes an improved methodology for estimating traffic accident cost savings in the transport appraisal. Four major problems from the existing framework are identified and their alternatives are suggested. First, casualties in the established approach are classified by just two types of 'killed' and 'injured'. This study supplies the indices of fatality further details. Namely, road victims are regrouped by 'killed', 'seriously injured', 'slightly injured', and 'accident reports'. Those of railways are similarly sorted by 'killed', 'seriously injured', and 'slightly injured'. Second, damage only accidents are not satisfactorily considered in the current arrangement. The accidents should be considered as one of the accident types and the social cost of them should also be evaluated. Third, the unit cost of accidents is given by the total value. The unit cost is consisted of several elements and each loss would be useful for a policy frame. This study breaks down the total figure into four pieces of costs, namely production loss, medical treatment, property loss, and administrative costs. Finally, there is inconsistency in the audit between roads and railways. Road accidents are analyzed by road types. On the other hand, patronage or others is the classification rule of rail accident costs. This paper suggests a way that the accident costs of two modes can be coherently estimated based on the level of services by each mode. The result of this study is expected to help frame more cautious social overhead capital investment policies.

• Journal of the Korean Society for Railway
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• v.20 no.2
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• pp.275-287
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• 2017

During the feasibility study of new rail lines, maintenance cost of railway infrastructure has mostly been estimated based on the track length and on simplified parameters; however, the estimation reliability can be improved by employing the correction factor from UIC 715, as well as the line classification in UIC 714. The correlations between maintenance cost and various parameters such as weighted track length based on line classification, radius of curvature, gradient and worn -out rate have been analyzed according to the case studies. Prediction of the maintenance cost has been carried out using the cost data, which were representative of the whole cost data; as a result, it was demonstrated that a cost model based on the line classification and the correction factor was more reliable than the existing models. Furthermore, possibilities of using data from both the track measurement vehicle and from the maintenance information system, which are under development, have been investigated and, based on this investigation, a combined cost model using line classification, radius of curvature, gradient and worn-out rate, among other factors, will be proposed in the near future.