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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of The Korean Society of Civil Engineers
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Journal DOI :
Korean Society of Civil Engeneers
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Volume & Issues
Volume 34, Issue 6 - Dec 2014
Volume 34, Issue 5 - Oct 2014
Volume 34, Issue 4 - Aug 2014
Volume 34, Issue 3 - Jun 2014
Volume 34, Issue 2 - Apr 2014
Volume 34, Issue 1 - Feb 2014
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In-plane Free Vibrations of Horseshoe Circular Arch
Lee, Byoung Koo ; Oh, Sang Jin ; Lee, Tae Eun ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1043~1052
DOI : 10.12652/Ksce.2014.34.4.1043
This paper deals with in-plane free vibrations of the horseshoe circular arch. Simultaneous ordinary differential equations governing free vibration of the arch are derived with respect to the radial and tangential deformations. Particularly, differential equations are obtained under the arc length coordinate rather than the angular one in order to extend the horseshoe arch whose subtended angle is greater than
radians. The differential equations are numerically solved for calculating the natural frequencies accompanying with the corresponding mode shapes. In parametric studies, effects of the rotatory inertia, slenderness ratio and circumferential arc length ratio on frequency parameters are extensively discussed.
Sustainable Design Method of Reinforced Concrete Beam Using Embodied Energy Optimization Technique
Yoon, Young-Cheol ; Kim, Kyeong-Hwan ; Yeo, DongHun ; Lee, Sang-Ho ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1053~1063
DOI : 10.12652/Ksce.2014.34.4.1053
This study presents a sustainable design method that optimizes the embodied energy of concrete beam based on the concept of sustainable development that effectively utilizes natural resource and energy within the range that our succeeding generation can afford to utilize. In order to get the flexural strength carrying the ultimate load, concrete beam sections are designed by optimization that consists of the embodied energy as a objective function and the requirements of design code as constrained conditions. The sustainable design can be used to minimize the embodied energy consumed in material production, construction, operation, demolition of the infrastructure. As a result of comparison of the cost and the embodied energy optimizations based on practical beam sections, it is shown that 20% embodied energy saving and 35%
emission saving are achieved by sacrificing 10% cost increase. The sustainable design method provides a new effective methodology that manages the strength design concept based on cost minimization together with economic feasibility and sustainability. In addition, the method is expected to be applied to more various structural design practices.
An Indeterminate Strut-Tie Model and Load Distribution Ratio for Reinforced Concrete Corbels
Chae, Hyun Soo ; Yun, Young Mook ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1065~1079
DOI : 10.12652/Ksce.2014.34.4.1065
The ultimate behavior of reinforced concrete corbel is complicated due to the primary design variables including the shear span-to-effective depth ratio a/d, flexural reinforcement ratio, load condition, and material properties. In this study, a simple indeterminate strut-tie model reflecting all characteristics of the ultimate strength and complicated structural behavior is proposed for the design of the reinforced concrete corbels with shear span-to-effective depth ratio of
. A load distribution ratio, defined as the fraction of applied load transferred by horizontal truss mechanism, is also proposed to help structural designers perform the design of reinforced concrete corbels by using the strut-tie model approaches of current design codes. For the development of the load distribution ratio, numerous material nonlinear finite element analyses of the proposed indeterminate strut-tie model were conducted by changing primary design variables. The ultimate strengths of reinforced concrete corbels tested to failure were evaluated by incorporating the proposed strut-tie model and load distribution ratio into the ACI 318-11`s strut-tie model method. The validity of the proposed model and load distribution ratio was examined by comparing the strength analysis results with those by the ACI 318-11`s conventional design method and strut-tie model methods of current design codes.
Effective Strengths of Concrete Struts in Strut-Tie Models of Reinforced Concrete Corbels
Chae, Hyun Soo ; Yun, Young Mook ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1081~1094
DOI : 10.12652/Ksce.2014.34.4.1081
The strut-tie model approach has proven to be effective in the ultimate analysis and design of structural concrete with disturbed regions. For the reliable analysis and safe design of the structural concrete, however, the effective strengths of concrete struts must be determined accurately. In this study, the equations of the effective strengths of concrete struts, which are useful for the three types of determinate and indeterminate strut-tie models of reinforced concrete corbels, were proposed. The effects of shear span-to-effective depth ratio, the vertical-to-horizontal force ratio, and flexural and horizontal shear reinforcement ratios were reflected in the development of the proposed equations. To examine the appropriateness of the proposed and existing equations, the ultimate strengths of 243 reinforced concrete corbels tested to failure were evaluated by using the three types of corbel strut-tie models.
Effect of Fineness Levels of GGBFS on the Strength and Durability of Concrete
Lee, Seung Tae ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1095~1104
DOI : 10.12652/Ksce.2014.34.4.1095
This paper presents the results of experimental work on both strength characteristics and durability of concrete or mortar having 50% ground granulate blastfurnace slag(GBS) with different fineness levels (4,450, 6,000 and
). Compressive and split tensile strength test results indicated that the concrete with a higher fineness level of GBS exhibited a better strength development due to the acceleration of latent hydraulic property at the later curing stage compared with ordinary portland cement concrete. Meanwhile, it was found that a higher fineness level of GBS showed some negative effects on the resistance against freezing-thawing action. However, incorporation of GBS to concrete, irrespective of fineness levels, significantly enhanced the chloride ions penetration resistance. The resistance against sulfate attack of mortar with GBS was greatly dependent on the attacking sources from sulfate environments.
Analysis of the Applicability of Parameter Estimation Methods for a Stochastic Rainfall Model
Cho, HyunGon ; Kim, GwangSeob ; Yi, JaeEung ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1105~1116
DOI : 10.12652/Ksce.2014.34.4.1105
A stochastic rainfall model, NSRPM (Neyman-Scott Rectangular Pulse Model), is able to reflect the cluster characteristics of rainfall events which is unable in the RPM (Rectangular Pulse Model). Therefore NSRPM has advantage in the hydrological applications. The NSRPM consists of five model parameters and the parameters are estimated using optimization techniques such as DFP (Davidon-Fletcher-Powell) method and genetic algorithm. However the DFP method is very sensitive in initial values and is easily converge to local minimum. Also genetic algorithm has disadvantage of long computation time. Nelder-Mead method has several advantages of short computation time and no need of a proper initial value. In this study, the applicability of parameter estimation methods was evaluated using rainfall data of 59 national rainfall networks from 1973-2011. Overall results demonstrated that accuracy in parameter estimation is in the order of Nelder-Mead method, genetic algorithm, and DFP method.
A Study on Target Standardized Precipitation Index in Korea
Kim, Min-Seok ; Moon, Young-Il ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1117~1123
DOI : 10.12652/Ksce.2014.34.4.1117
Water is a necessary condition of plants, animals and human. The state of the water shortage, that drought is globally one of the most feared disasters. This study was calculated target standardized precipitation index with unit of region for judgment and preparation of drought in consideration of the regional characteristics. First of all, Standardized Precipitation Index (3) were calculated by monthly rainfall data from rainfall data more than 30 years of 88 stations. Parametric frequency and nonparametric frequency using boundary kernel density function were analysed using annual minimum data that were extracted from calculated SPI (3). Also, Target return period sets up 30 year and target SPI analysed unit of region using thiessen by result of nonparametric frequency. Analyzed result, Drought was entirely different from severity and frequency by region. This study results will contribute to a national water resources plan and disaster prevention measures with data foundation for judgment and preparation of drought in korea.
Non-Parametric Low-Flow Frequency Analysis Using RCPs Scenario Data : A Case Study of the Gwangdong Storage Reservoir, Korea
Yoon, Sun Kwon ; Cho, Jae Pil ; Moon, Young Il ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1125~1138
DOI : 10.12652/Ksce.2014.34.4.1125
In this study, we applied an advanced non-parametric low-flow frequency analysis using boundary kernel by Representative Concentration Pathways (RCPs) climate change scenarios through Arc-SWAT long-term runoff model simulation at the Gwangdong storage reservoir located in Taeback, Gangwondo. The results show that drought frequency under RCPs was expected to increase due to reduced runoff during the near future, and the variation of low-flow time series was appeared greatly under RCP8.5 scenario, respectively. The result from drought frequency of Median flow in the near future (2030s) compared historic period, the case of 30-year low-flow frequency was increased (the RCP4.5 shows +22.4% and the RCP8.5 shows +40.4%), but in the distant future (2080s) expected increase of drought frequency due to the reduction of low-flow (under RCP4.5: -4.7% and RCP8.5: -52.9%), respectively. In case of Quantile 25% flow time series data also expected that the severe drought frequency will be increased in the distant future by reducing low-flow (the RCP4.5 shows -20.8% to -60.0% and the RCP8.5 shows -30.4% to -96.0%). This non-parametric low-flow frequency analysis results according to the RCPs scenarios have expected to consider to take advantage of as a basis data for water resources management and countermeasures of climate change in the mid-watershed over the Korean Peninsula.
Estimation of High Resolution Daily Precipitation Using a Modified PRISM Model
Kim, Jong Pil ; Lee, Woo-Seop ; Cho, Hyungon ; Kim, Gwangseob ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1139~1150
DOI : 10.12652/Ksce.2014.34.4.1139
This study modified the Parameter-elevation Regression on Independent Slopes Model (PRISM) and investigated the applicability of the modified model (M-PRISM) in estimating
gridded daily precipitation over South Korea. The model parameters of M-PRISM were estimated by regression curves and were validated using the Jackknife method at the Korean Meteorological Administration (KMA) stations. The results indicate that M-RPISM shows better performance in estimating the frequency of daily precipitation than PRISM while M-PRISM has similar performance to PRISM in estimating the daily precipitation amount. Thus the M-PRISM model proposed in this study can be very useful to estimate high resolution daily precipitation.
Summer Precipitation Variability in the Han River Basin within the Context of Global Temperature Gradients
Jeong, Min-Su ; Kim, Jong-Suk ; Moon, Young-Il ; Hwang, Sung-Hwan ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1151~1159
DOI : 10.12652/Ksce.2014.34.4.1151
In this study, two global simple indices are used to investigate climate variability and change in observations. Land-Ocean Contrast (LOC) is an index of area-averaged surface temperature contrast between land and ocean. Meridional Temperature Gradient (MTG) is defined as the mean meridional temperature gradient in the Northern Hemisphere from mid to high latitude and sub-tropical zonal bands. These indices have direct or indirect effects on changing in atmospheric circulations and atmospheric moisture transport from north-south or east-west into East Asia (EA). In addition, warm season hydrometeorology in EA is highly associated with water supplies for coupled human and natural systems including drinking water, irrigation, hydropower generation as well as fisheries. Therefore, in this study, we developed an empirical separation approach for summer rainfall from typhoon and monsoon. An exploratory analysis was also conducted to identify the regional patterns of summer monsoon precipitation over the Korean peninsula within the context of changes in different types of temperature gradients. The results show significant and consistent changes in summer monsoon rainfall during the summer season (June-September) in South Korea.
A Study on Awareness Difference of Local Residents and Public Officials to River Projects
Kang, Hyeongsik ; Kim, Minseon ; Cho, Sungchul ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1161~1170
DOI : 10.12652/Ksce.2014.34.4.1161
This study aims to analyze civil society consciousness to river projects, examine the current state of resident participation, and suggest development directions for river policy. For this, this study conducted a survey of 1,200 local residents and 100 public officials living and working in the river project areas. The result demonstrates the necessity of formulating river policy in a way that recognizes voices of various policy stakeholders, strengthens partnership among resident groups, and promotes a trend shift in river restoration to reflect residents` consciousness.
Comparing Calculation Techniques for Effective Rainfalls Using NRCS-CN Method: Focused on Introducing Weighted Average and Slope-based CN
Moon, Geon-Woo ; Yoo, Ji-Young ; Kim, Tae-Woong ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1171~1180
DOI : 10.12652/Ksce.2014.34.4.1171
The NRCS-CN method is generally used to estimate effective rainfalls in a basin. However, since the curve number which plays a critical role in the NRCS-CN method was originally developed for US watersheds, it is limited to be directly applied to other basins outside the United States. Therefore various modifications have been suggested to revise the NRCS-CN for specific watershed condition. This study introduced the weighted average method and the slope-based CN to estimate effective rainfalls available for Korean watersheds and compared with the observed direct runoff. The overall results achieved from this study indicated that the adjusted slope-based CN considerably increases effective rainfalls in general and makes the duration of effective storm longer. Based on the statistical error analysis performed for various modifications of NRCS-CN, the weighted average method with the adjusted slope-based CN has highest precision with the observed direct runoff. In addition, after analyzing the relation between the initial loss estimated from rainfall-runoff observations and the potential maximum retention from GIS-based data, it turns out that the assumption of linear relationship between the initial loss and the potential maximum retention is not available for Korean watersheds.
A Laboratory Study on Erosional Properties of the Deposit Bed of Kaolinite Sediments
Kim, Yong-Muk ; Kim, Hyun-Min ; Hwang, Kyu-Nam ; Yang, Su-Hyun ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1181~1190
DOI : 10.12652/Ksce.2014.34.4.1181
In this study, the erosional parameters for deposit beds were quantitatively estimated domestically for the first time through the erosion tests using an annular flume. Four erosion tests were carried out for the deposit beds with different consolidation structures, which were obtained by consolidating the kaolinite slurries for a given time durations. Results of erosion tests showed that the bed shear strength
increased with the consolidation time and bed depth. The erosion rate
was also shown to be related well with the excess shear stress
which was given by the difference between flow shear stress
and bed shear strength
. While the logarithm of the erosion rate was linearly related with the excess shear stress as
, however, the erosion rate decreased rapidly with it when
. These erosion test results were also shown to be good enough to verify by comparing with the test results from previous studies and a new equation was suggested to describe the erosion rate more well in the region of
Study of Rip Current Warning Index Function according to Real-time Observations at Haeundae Beach in 2012
Choi, Junwoo ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1191~1201
DOI : 10.12652/Ksce.2014.34.4.1191
The rip current warning index function, which estimates the likelihood of dangerous rip current in the real-time rip current warning system operating to help mitigate against rip current accidents at Haeundae beach, was studied. The rip current warning index evaluated as a function of various real-time observations was developed based on Choi et al. (2013b). This study shows a version of rip current warning index improved by including the effect of wave direction and spreadings of frequency-directional spectrum on rip current likelihood. The wave and tidal observations in 2012 at Haeundae coast were applied to the rip current index function, and its performances at several real events found based on CCTV images were presented and analyzed.
Analyses of Riverbed Changes and Physical Disturbance Evaluations by Weir Installation in a Reach
Choi, Heung Sik ; Lee, Woong Hee ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1203~1213
DOI : 10.12652/Ksce.2014.34.4.1203
The hydraulic characteristics and the patterns of riverbed change had been analysed by HEC-RAS simulation in a reach of Cheong-mi river with and without weir. The corresponding physical disturbance had been evaluated with the method suggested by K-water (2008). The occurrences of low physical disturbance score coincide with the corresponding high bed changes by weir installation. The effects of physical disturbance coincide with the patterns of riverbed change along river reach which shows riverbed change is the important factor to physical disturbance. In case of installation of additional weirs at up and down stream sections of no disturbance effect by the existing weir, no physical disturbances occur in certain sections with confirming the appearance of the similar disturbance scores between the simulation results of with and without additional weir installations. In case of installation of additional weirs at up and down stream sections of disturbance effect margins by the existing weir, physical disturbances occur at every section. In case of installation of additional weirs at up and down stream sections within disturbance effect by the existing weir, low physical disturbance scores are given at every section because of superposition of disturbance along river reach. The physical disturbance would be minimized such that the additional weir is installed with sufficient distances of no disturbance and bed change effects along river reach.
Mechanical Characteristics of Basalt in Jeju Island with Relation to Porosity
Moon, Kyoungtae ; Park, Sangyeol ; Kim, Youngchan ; Yang, Soonbo ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1215~1225
DOI : 10.12652/Ksce.2014.34.4.1215
Volcanic rocks formed from magma near the earth surface commonly show vesicular structures due to exsolution of gaseous phases in magma. The distinction and the amount of vesicles are greatly various, but there are few researches on the effect of volume percentage of vesicles on the mechanical properties. In this study, mechanical characteristics of volcanic rocks in relation to the porosity are investigated through experimental tests with Jeju basalt. Two methods (the buoyancy method and the caliper method) are adopted for measuring porosity. And unconfined compressive strength, elastic modulus, tensile strength, and elastic wave velocity are plotted against porosity in order to propose the empirical relations after the regression analysis. Also, unconfined compressive strength and the elastic modulus in relation to the elastic wave velocity are proposed with the analysis. In the case of vesicular rocks with more than 5% porosity, it is found that the buoyancy method provides more accurate estimation of porosity than the caliper method. The unconfined compressive strength, the elastic modulus, and the elastic wave velocity decrease curvilinearly with increasing in porosity. Also, the unconfined compressive strength and the elastic modulus increase linearly with increasing in elastic wave velocity.
Rheological Characteristics and Debris Flow Simulation of Waste Materials
Jeong, Sueng Won ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1227~1240
DOI : 10.12652/Ksce.2014.34.4.1227
Abandoned mines often cause environmental problems, such as alteration of landscape, metal contamination, and landslides due to a heavy rainfall. Geotechnical and rheological tests were performed on waste materials corrected from Imgi waste rock dump, located in Busan Metropolitan City. Debris flow mobility was examined with the help of 1-D BING model which was often simulated in both subaerial and subaqueous environments. To determine flow curve, we used a vane-penetrated rheometer. The shear stress (
)-shear rate (
) and viscosity(
)-shear rate (
) relationships were plotted using a shear stress control mode. Well-known rheological models, such as Bingham, bilinear, Herschel-Bulkley, Power-law, and Papanastasiou concepts, were compared to the rheological data. From the test results, we found that the tested waste materials exhibited a typical shear shinning behavior in
plots, but the Bingham behavior is often observed when the water contents increased. The test results show that experimental data are in good agreement with rheological models in the post-failure stage during shearing. Based on the rheological properties (i.e., Bingham yield stress and viscosity as a function of the volumetric concentration of sediment) of waste materials, initial flowing shape (5 m, 10 m, and 15 m) and yield stress (100 Pa, 200 Pa, 300 Pa, and 500 Pa) were input to simulate the debris flow motion. As a result, the runout distance and front velocity of debris flow are in inverse propositional to yield stress. In particular, when the yield stress is less than 500 Pa, most of failed masses can flow into the stream, resulting in a water contamination.
Preferences Factors Analysis for Car-sharing
Kim, SukHee ; Lee, Kyujin ; Choi, Keechoo ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1241~1249
DOI : 10.12652/Ksce.2014.34.4.1241
This study presents preferences factors analysis of Car-sharing in Suwon. Approximately, 60% of the citizens prefer car-sharing and consider using it. The results of analysis by factors show higher preferences in these groups of travelers: man, younger, a resident of detached house and efficiency apartment, user of public transportation who finds it uncomfortable, traveler without vehicles, and traveler using car 1 to 3 times a week. The potential demand for car-sharing was highest in the residential areas and around the stations. Travelers prefer to pay the fee by the hour, which the fair value was 7,967 won. For the trip purpose of business, shopping and leisures, car-sharing is more preferred than taxi and rental cars. Findings will contribute to determining the direction of policy for the car-sharing.
Estimating Greenhouse Gas Emissions from Marine Vessels in the Port of Busan using PORT-MIS and Vessel Specification Databases
Kim, Jongjin ; Shin, Kangwon ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1251~1259
DOI : 10.12652/Ksce.2014.34.4.1251
This study presents the linkage method combining the existing Port Management Information System (PORT-MIS) DB with the scattered vessel activity data sets including the hotelling and maneuvering characteristics and specification information of the vessels arriving and departing from the port of Busan from January 2009 to June 2010. By linking the data sets, this study made three types of vessel activity databases: L-PORT-MIS DB with low-level vessel activities, M-PORT-MIS DB with medium-level vessel activities such as hotelling time, H-PORT-MIS DB with high-level vessel activities such as hotelling time, engine power, etc. The greenhouse gas (GHG) emissions estimation results show that total GHG emissions decreases when the detailed vessel activities are employed. This decrease in the total GHG emissions by the level of vessel activities implies that the GHG emissions from the low and medium level vessel activities are overestimated due to the aggregated hotelling/maneuvering times and speeds resulting from the past vessel specifications. Therefore, the GHG emissions using the H-PORT-MIS DB are more reliable GHG emission estimates in that the vessel specifications and the observed hotelling time of each vessel are employed in the estimation process. Hence, the high-level vessel activity dataset should be constructed to implement more suitable countermeasures for reducing the GHG emissions in the port of Busan.
Comparison of Relative Weights of Cost for Road-bed Construction and Energy on Life Cycle Cost of Railroad -in Case of Seoul-pusan High Speed Rail
Suh, Sunduck ; Kim, Jeong Hyun ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1261~1267
DOI : 10.12652/Ksce.2014.34.4.1261
It is generally recognize that the weight of energy cost for railroad alignment in the life cycle cost is higher than that for roadway. This study analyzed the relative weights of railroad road-bed construction cost and energy cost in the case of Seoul-Pusan High Speed Rail. Recently, the optimization of railroad alignment with computerized methodology has been studies. The optimization is supposed to aim the minimization of life cycle cost including the energy cost as well as the minimization of the construction cost. The operation period of the Seoul-Pusan High Speed Rail is limited to ten years, then various future operation scenario were developed for the next 20 years. The weight of energy cost is estimated 10~30% of the construction cost by scenario, and it is lower than the figure generally expected. It may be meaningful to provide the method to include the energy cost in the railroad alignment optimization.
A Study on the Analysis of Urban Highways Traffic Accident`s Impact Factors Based on Building Discriminant Models - In Busan Metropolitan City -
Jeong, Yong-Hwa ; Choi, Yang-Won ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1269~1278
DOI : 10.12652/Ksce.2014.34.4.1269
The urban highway, which is a motorway constructed to solve traffic issues, has the characteristic of extremely high damage to life during traffic accidents because the speed of vehicles is higher than typical roadways. In particular, because traffic accidents involving serious injuries hold a very important place among overall traffic accidents, analysis on factors affecting the occurrence of traffic accidents involving serious injuries must be considered with priority when establishing a reduction measure. Therefore, the study built a model that was capable of distinguishing the degree of the factors as part of microscopic analysis for investigating the complex effect of many elements concerning the occurrence of traffic accidents involving serious injuries in urban highways. The results are as follows. First, discriminant model showed a comparatively high level in overall accuracy rates, and, considering the correlation ratio, the models were determined to be valid, as all characteristics of the factors were clearly distinguished. Second, the problems of traffic accidents involving serious injuries on urban highways according to each factor, were clearly drawn out through the discriminant model. Third, the improvement measure for the problems drawn out from the discriminant models were clearly proposed.
Development of the U-turn Accident Model at Signalized Intersections in Urban Areas by Logistic Regression Analysis
Kang, Jong Ho ; Kim, Kyung Whan ; Kim, Seong Mun ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1279~1287
DOI : 10.12652/Ksce.2014.34.4.1279
The purpose of this study is to develop the U-turn accident model at signalized intersections in urban areas. The characteristics of the accidents which are associated with U-turn operation at 3 and 4-legged signalized intersections was analyzed and the U-turn accident model was developed by regression analysis in Changwon city. First, in order to analyze the effectiveness on traffic accidents by U-turn installation, the difference of mean of traffic accident number are measured between two groups which are composed by whether or not U-turn installation the groups by Mann-Whitney U test. The result of significance test showed that intergroup comparison on mean by accident types made difference except rear-end accident type and by accident locations exit section only showed difference in significance level at 4-legged intersections, so the accident number have more where the U-turn is permitted than not. Response measures about the number of accidents were classified by whether accidents occurred and accident model were constructed using binomial logistic regression analysis method. The developed models show that the variables of conflict traffic, number of opposing lane are adopted as independent variable for both intersections. The variables of longitudinal grade for 3-legged signalized intersection and number of crosswalk for 4-legged signalized intersection at which the U-turn is permitted is adopted as independent variable only. These study results suggest that U-turn would be permitted at the intersection where the number of opposing lane is more than 3.5 each, the longitudinal grade of opposing road is upward flow and there is need to establish the U-turn traffic sign at signalized intersections.
A Comparative Study on Productivity Analysis of Automated Pavement Crack Sealing Machines
Seo, Won-Jung ; Yoo, Hyun-Seok ; Kim, Young-Suk ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1289~1298
DOI : 10.12652/Ksce.2014.34.4.1289
Pavement crack sealing method, which is one of the methods to maintain and repair the road, prevents the extending of cracks by repairing cracks in its early occurrence and has already been applied to many roadworks in advanced foreign country for a long time. But in the conventional crack sealing method, traffic accidents occur frequently during the repair because it`s commonly performed on the heavy traffic road or highway. It also has some difficulties in securing the safety of workers from the risk of burns caused by heated sealant. In an effort to solve these problems, automated pavement crack sealing machines such as ARMM, OCCSM, TTLS have been developed in advanced foreign country since early 1990s. Also APCS in 2004 and ACSTM in 2013 were already developed domestically. However, since these automated crack sealers developed from a number of research institutions have different test-bed conditions and productivity measurement models, it`s difficult to compare and evaluate them objectively. In this study, the image processing time of the respective machines and the movement time of each motion on the work process were estimated by using fully autonomous mapping and semi-automatic mapping in order to measure the productivity in the same environmental conditions. In addition, the productivity measurement test-bed reflected domestic road characteristics was designed to estimate and compare the productivity of the automated crack sealing machines.
Construction Cost Estimate Modeling of Roundabout at Preliminary Design Stage in Jeju
An, Jin-Hong ; Lee, Dong Wook ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1299~1306
DOI : 10.12652/Ksce.2014.34.4.1299
Recently, there are many roundabouts installation works which are ordered to provide convenient transportation to road users as well as to eliminate traffic accidents and traffic delays. This study propose an approximate construction cost estimation model for early stages of roundabout construction. The model is designed considering the conditions of the early stage roundabout construction sites in Jeju. The regression equation of approximate construction cost was derived through regression analysis of 25 design data of roundabout construction in Jeju, and it was analyzed to have a high prediction accuracy. Finally, results verifies high prediction accuracy of the derived regression equation. Difference between the estimation cost and the design cost was only 2.3%, 3.7%, and 5.8% that verifies the high accuracy of the proposed approximate construction cost estimation model.
The Evaluation of the Purchase Social Housing on the Characteristics of Location and Housing in Busan
Choi, Yeol ; Park, Sung Ho ; Ha, Kyu-Yang ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1307~1315
DOI : 10.12652/Ksce.2014.34.4.1307
This study aims to analysis of determinants of the residents satisfaction of purchased rental housing and currently being implemented policy of supporting low-income families are empirically evaluated through the residential evaluation of purchased rental housing residents. Purchased rental housing users are possible to live in currently residing community consistently, have advantages for fewer problems of the phenomenon of social isolation, exclusion and preventing slumism of low-income families, are expected to increase in the future. First of all, the characteristics of residential environment, housing expenses and a head of household were examined for the residential environment evaluation of the residents of purchased rental housing, on the basis of this, the characteristics of internal and external house and residential location are examined each for the determinants of the residential environment satisfaction of purchased rental housing. The variables that affect residential satisfaction according to residential location are public facilities, educational facilities and welfare facilities respectively. In particular, the higher the satisfaction of access to welfare facilities, the higher the satisfaction of residential location of purchased rental housing was analyzed. The variables affecting the residential satisfaction according to the internal and external characteristics of house are significant in window status, cracking, heating facilities, housing scale and management.
A study on the Spatial Sampling Method to Minimize Spatial Autocorrelation of Spatial and Geographical Data
Lee, Youn Soo ; Lee, Man Choul ; Lah, Kyung Beom ; Kang, Jun Mo ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1317~1325
DOI : 10.12652/Ksce.2014.34.4.1317
The study focused on analyzing spatial sampling by minimizing autocorrelation of spatial based on spatial and geographical data. The study concluded two different ways of minimizing autocorrelation. First, it was important to use suitable spatial sampling method to alienate spatial autocorrelation from spatial or geographical data. The shear distribution rate of public transportation in Seoul resulted in high rate of autocorrelation. However, the study showed samples eliminated autocorrelation when samples were extracted with reasonable distance(above 400m) apart. Without spatial sampling the distortion of spatial data leads to false results; therefore, spatial sampling is indispensable. Second, factors which fluctuates shear distribution of public transportation spatial sampling changed before and after spatial sampling. This was caused by incapable of controling inherent spatial autocorrelation of the data.
Improvement of Public Announcement of Topographical Drawing for Linear-Type Infrastructure
Moon, Jung Kyun ; Kwon, Hun Yeong ; Cho, Hyoung Sig ; Sohn, Hong Gyoo ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1327~1334
DOI : 10.12652/Ksce.2014.34.4.1327
Linear form of public works such as roads, railways and rivers, generally used as long work crossing administrative districts, can be several hundreds km length and narrow. These linear forms use SCM sheets, which do not include the quadrangle shape, to make a public announcement of topographical drawing in order to get the work approval. the Integrated measurement channel investigation and cadastral act that are established in 2009 apply the ITRF for the composition of design and construction books and coordinates of topographical map in order to get the work approval. However according to the article 5 of additional clause, while the cadastre is maintaining local coordinates, if there is a technical error in the content of the Public Announcement of Topographical Drawing that used the SCM, the question of responsibility of land borders and the efficacy or not of the announcement is raised as an administrative measure. After analysing the causes and enforcing coordinate conversion and correction taking into account linear form work`s features, the result was reflected in the existing SCM. As a conclusion, the present study proposes the improvement of the procedures of the Public Announcement of Topographical Drawing.
Estimation of Bathymetry Changes using Hyperspectral Measurements -Focused on Haeundae beach-
Yang, Intae ; Jo, Young-Heon ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1335~1342
DOI : 10.12652/Ksce.2014.34.4.1335
Shallow water depths were estimated using Compact Airborne Spectrographic Imager (CASI)-1500 and mapped to analyze the bottom bathymetry changes due to the rip currents in Haeundae beach, South Korea for the first time. The depths were estimated empirically using the maximum reflectances from 420nm to 597nm wavelength of CASI and 47 in situ water depth measurements, which were compared with ground-truth bathymetry measurements. The comparisons showed that the RMSE was 1.1m with a correlation coefficient of 0.76. In addition, CASI imagery showed remarkably detailed bottom features, especially those resulting from the rip currents within the beach. Two different channels carved by the rip current were analyzed and characterized with respect to the width and slope compared to surrounding regions. While the west side of the channel showed a wide and gentle slope, the east side of the channel showed a narrow and steep slope. The estimated bathymetry map revealed that the uneven offshore bottom features were related to the transport and accumulation of sediments by the rip current, which reaches hundreds of meters offshore. Accordingly, the accumulated sediments were estimated by adding topography changes compared to the depths of the non-rip current regions. The sediments were accumulated in off channels as much as almost twice the amount of annual sand supplements along the Haeundae beach.
Development and Estimation of Low Price-Small-Autopilot UAS for Geo-spatial Information Aquisition
Han, Seung Hee ;
Journal of The Korean Society of Civil Engineers, volume 34, issue 4, 2014, Pages 1343~1351
DOI : 10.12652/Ksce.2014.34.4.1343
Recent technological advances in wireless networks and microelectromechanical systems (MEMS) have led to the development of different types of mini-UAVs and their utilizations in various ways. This study endeavors to develop a low-cost mini-UAV with autonomous flight capability, in order to obtain geospatial information of a small or medium-sized area, and also assess its flight stability by comparing the predetermined flight paths against the actual flight paths. Based on a post-development flight test, stable flight has been proven achievable as follows: the maximum endurance speed is 1 hour, the flying distance is 50km, the horizontal accuracy of flight paths is about
, and the altitude accuracy is about
. Therefore, it is deemed that high-resolution images which can be utilized for geospatial information are obtainable. This indicates that a UAV flying at an altitude of 200m can acquire images across a
area on the ground within 25 minutes, which validates its high usability for obtaining high-solution images at low altitudes in the future.