• International Journal of Highway Engineering
• /
• v.18 no.2
• /
• pp.73-82
• /
• 2016

PURPOSES: The national highways and expressways in Korea constitute a total length of 17,951 km. Of this total length of pavement, the asphalt pavement has significantly deteriorated, having been in service for over 10 years. Currently, hot in-place recycling (HIR) is used as the rehabilitation method for the distressed asphalt pavement. The deteriorated pavement becomes over-heated, however, owing to uncontrolled heating capacity during the pre-heating process of HIR in the field. METHODS: In order to determine the appropriate heating method and capacity of the pre-heater at the HIR process, the heating temperature of asphalt pavement is numerically simulated with the finite element software ABAQUS. Furthermore, the heating transfer effects are simulated in order to determine the inner temperature as a function of the heating system (IR and wire). This temperature is ascertained at $300^{\circ}C$, $400^{\circ}C$, $500^{\circ}C$, $600^{\circ}C$, $700^{\circ}C$, and $800^{\circ}C$ from a slab asphalt specimen prepared in the laboratory. The inner temperature of this specimen is measured at the surface and five different depths (1 cm, 2 cm, 3 cm, 4 cm, and 5 cm) by using a data logger. RESULTS: The numerical simulation results of the asphalt pavement heating temperature indicate that this temperature is extremely sensitive to increases in the heating temperature. Moreover, after 10 min of heating, the pavement temperature is 36%~38% and 8%~10% of the target temperature at depths of 25 mm and 50 mm, respectively, from the surface. Therefore, in order to achieve the target temperature at a depth of 50 mm in the slab asphalt specimen, greater heating is required of the IR system compared to that of the gas. CONCLUSIONS : Numerical simulation, via the finite element method, can be readily used to analyze the appropriate heating method and theoretical basis of the HIR method. The IR system would provide the best heating method and capacity of HIR heating processes in the field.

• Journal of Korean Society of Transportation
• /
• v.27 no.5
• /
• pp.39-49
• /
• 2009

This research analyzes current pedestrian's safety zone choice standard problem and described about correct standard re-thesis at real. About problem of pedestrian traffic accidents to specific item statistical data to basis ramification of pedestrian traffic accidents, occurrence type of accident, action type etc. synthetically analyze and mark pedestrian's safety zone by countermeasure for decrease of pedestrian traffic accidents and utilize operating domestic outer garment reward and drew domestic Zone30 zone choice standard. Also, because analyzing effect that traffic discharge and speed through on-the-spot probe get in pedestrian thinking, presented quantitative standard, and analyze accident special quality of back pedestrian traffic accidents occurrence number of item and so on do accident type beside quantitative standard, road function, accident latitude and present standard. Specially, take advantage of statistical data of traffic accidents and put emphasis in pedestrian safety. Also, because establishment standard about safety facility establishment of Zone30 zone and systematic thesis of operation way do not consist, standard guide of consistency it is no and does equipment that is established in Zone30 zone because confusion happens by each local unit presented establishment and operation way, and present Zone30 zone.

• Journal of Technology Innovation
• /
• v.17 no.2
• /
• pp.131-158
• /
• 2009

We examine the effects of environmental or organizational factors on the performance of TLOs(technology transfer offices) in the PRIs(Public research institutes) using SFA(Stochastic Frontier Analysis), a technique for estimating the efficiency of DMUs(decision making units). In SFA, independent variables are assumed to determine the efficient production technique(production frontier) or affect the efficiency of DMUs. Previous researchs show that input variables such as number of personnel, R&D expenditure affect the production frontier while environmental or organizational variables affect the efficiency. We tried to estimate various types of models to find out whether environmental or organizational variables affect output variables differently from the previous research. Main empirical findings are as follows. First, R&D expenditure tends to increase all output variables considered. Second, environmental factors such as type of institutions and location of institutions affect the level of outputs. Third, organizational factors such as reward system for technology transfer also appear to affect the output variables. Fourth, environmental or organizational variables affect the production frontier directly rather than affect the efficiency of DMUs. Lastly, the efficiency of each DMU appear to be 1 or near to 1. Since almost all DMUs are equally efficient, it may not be effective to evaluate technology transfer activities of PRIs by efficiency criteria. We believe that this research should be complemented by additional data. More general types of production function need to be considered, and new techniques with concepts like output distance functions need to be developed to analyse multiple outputs simultaneously.

• Journal of Korea Water Resources Association
• /
• v.35 no.3
• /
• pp.321-330
• /
• 2002

This study aims at the analysis of the geomorphological instantaneous unit hydrograph model (GIS-GIUH) with geographic information system for the rainfall-runoff analysis of watershed which is ungaged or doesn't have sufficient hydrologic data. The rainfall-runoff analysis was performed in Wi stream(Dongkok, Koro, Miseung, Byeungchun, Hyoreung, Museung) which is a representative experimental river basin of IHP. In the process of analysis of the GIUH model, developed GIS-GIUH model and Rosso-GIUH model were applied the study basin and computed hydrographs by these models were compared with observed hydrograph. The GiS-GIUH model shows more closely to the observed hydrograph than Rosso-GIUH model in the peak discharge of the hydrograph. For the development of the GIS-GIUH model, Gamma function factor N was given by N=3.25( $R_{B}$/ $R_{A}$)$^{0.126}$ $R_{L}$$^{-0.055}$, which is the relation of the watershed geomorphological factor, K was also obtained as K=1.50( $R_{A}$/( $R_{B}$. $R_{L}$))/$^{0.10}$.(( $L_{{\Omega}}$+ $L_{{\Omega}-1}$)/V)$^{0.37}$. As the results of analysis, it was found that GIS-GIUH model can be applied to an ungaged watersheds.eds.

• Korean Journal of Soil Science and Fertilizer
• /
• v.17 no.2
• /
• pp.161-166
• /
• 1984

The Cheju citrus orchards have been chemically fertilized with both phosphates high in Ca and Mg contents and potassium. The amount of chemical fertilizers consumed per unit area of cultivated land and the ratios of $P_2O_5$ and $K_2O$ to N in chemical fertilizers applied were much higher in the Cheju Island than those of the Korean mainland. These trends were particularly prominant in Southern Cheju where 70% of the Cheju citrus orchards are located. As the result of heavy applications of phosphate fertilizers, the available phosphorus of citrus orchard soils increased with increasing number of years under cultivation. The available phosphorus of sub-soil increased slightly with the number of years under cultivation compared to that of surface soil. Base saturation and pH increased with the number of years under cultivation, inasmuch as exchangeable bases such as Ca, Mg and K increased predominantly, but the cation exchange capacity did not vary in the citrus orchard soils.

• Childhood Kidney Diseases
• /
• v.9 no.1
• /
• pp.69-75
• /
• 2005

Purpose : The most important management of congenital hydronephrosis consists of the early diagnosis and evaluation of the pathologic abnormalities of congenital hydronephrosis. This study was conducted to investigate the different causes of hydronephrosis and its clinical outcome. Methods : 54 live neonates who were hospitalized and diagnosed with congenital hydronephrosis at Chungnam National University Hospital from Aug. 1998 to Aug. 2003 were retrospectively analyzed. Results : Hydronephrosis(renal pelvic AP diameter $gt;5 mm) was postnatally detected in 54 cases(2.1%) among 2,539 neonates who were hospitalized from Aug. 1998 to Aug. 2003. There were three times more males than females. Additional imaging studies revealed that ureteropelvic junction obstruction was the most common postnatal diagnosis(48.7%), followed by multicystic dysplastic kidney, vesicoureteral reflux and duplication kidney with ureterocele. Spontaneous regression of hydronephrosis was revealed in 25 renal units(75.8% ) of mild hydronephrosis, 14 renal units of moderate hydronephrosis and 1 renal unit of severe hydronephrosis. Operative correction were carried out in 14 renal units(70%) of severe hydronephrosls. Conclusion : The most common established cause of congenital hydronephrosis in this study was ureteropelvic junction obstruction. There are many cases of spontaneous regression in mild to moderate congenital hydronephrosis. Urinary tract infections occur in many neonates with hydronephrosis. Therefore, early detection and evaluation of congenital hydronephrosis and continuous follow-up at regular intervals are necessary for conservation of renal function. (J Korean Soc Pediatr Nephrol 2005;9:69-75)

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.31 no.3
• /
• pp.247-255
• /
• 1995

This paper describes a personal computer(PC) based color fish finder to improve some problem of the commercial one. The commercial fish finder has no function of the echo data logging and replaying. The authors developed two types of the PC based color fish finder. One is a master type composed of a PC, a digital input-output board, and analog to digital converting (A/D) board and an ultrasonic transceiver unit, the other is a slave type composed of a PC and an A/D board. To test the performances of the master type experiments were carried out in air and in a water tank. It is found that the designed master type fish finder displays very well an eight-colored echogram by one dot resolution to the left side of the PC monitor. Also, the depth of echo signal was corresponds very well to the range from the transducer to a target. The sampling interval of echo signal is about 0.1m and the time of A/D conversion is 30 $\mu$sec. On the other hand, to test the performances of the slave type a raw data of echo signals from a data logger was supplied directly or via RF transceivers to the slave type one. From this experiment, it is confirmed the slave type is useful to replay the echo signal from the data logger or a telesounder.

• Korean Journal of Remote Sensing
• /
• v.20 no.2
• /
• pp.91-102
• /
• 2004

This paper reflects the estimation of using the EOC(Electro-optical Camera) images supporting GIUH(geomorphological instantaneous unit hydrograph) approach. We have analyzed GIUH in its density and frequency distribution by creating a DEM(digital elevation model) for the sub basin produced from the EOC images and examined topographical and hydrological application possibility of the EOC images. In this process, we have topographical basin characteristic analysis that use the remote sensing technique analyzing the DEM creation process of the EOC stereo images by studying the basic topographical hydrology analysis about abstraction technique since it is flirty complex and is more time-consuming than other method. we executed statistical analysis of a basin size and river length using the frequency function after divided lattice spacing applied have to the sub river basin from the image data and the digital map into 10m intervals ranging from 10m to 100m. After comparing and examining the peak and time to peak of the GIUH, we proceeded with a comparative analysis by lattice concerning the topographical divergence rate, area ratio, length ratio. Accumulating the peak and time to peak of the GIUH is altered to non-linear form in accordance to lattice dimension as well as basin factor. It was proved that the lattice dimension is one of the important factors about the peak and time to peak of the GIUH.

• Journal of Korea Port Economic Association
• /
• v.25 no.3
• /
• pp.229-250
• /
• 2009

This paper aims to implement an empirical research about the efficiency of America and Northeast Asia pots, and to suggest an effective strategy which can operate these ports more well. This study tries to apply the Data Envelopment Analysis(DEA) model to America and Northeast Asia ports. DEA is a methodology of comparing the relative efficiency of each decision making unit(DMU) by comparing it with other DMUs having similar input and output structure, and is specially very useful when a form of production function of each DMU such as a port is not known. DEA provides the extent of inefficiency of DMUs, which is practically useful information (like the efficiency score and reference sets) required to improve efficiency. This paper analyzed the relative efficiency of 35 ports in America and Northeast Asia for 3 years from 2005 to 2007 through DEA-CCR, DEA-BCC model and scale efficiency. Accordingly, this paper evaluates the efficiency of America and Northeast Asia ports, grasps the position at the present time, and suggests an advanced direction in future.

• Korean Journal of Soil Science and Fertilizer
• /
• v.48 no.5
• /
• pp.428-435
• /
• 2015

Pedotransfer functions (PTFs) were developed for each soil horizon to estimate hydraulic characteristics of mountainous forest soils in South Korea. Twenty one dominant soil series from 8 soil catenae such as granite-originated catena and volcanic ash-originated catena were selected for the study; gravel contents of selected soils were 10% or lower. Saturated conductivity (Ks) was measured for each horizon in situ. Particle size distribution and organic matter content of each horizon were also determined. Based on correlation analysis with total data set, sand separate showed positive relationship with Ks ($r=0.24^*$) while clay separate had negative relationship with Ks ($r=-0.29^{**}$). The correlation coefficients of sand, clay, and organic matter content with Ks increased to $0.41^{**}$, $-0.67^{***}$, and $0.58^{***}$, respectively, using data from granite- or gneiss-originated catena with exception of volcanic ash-originated catena and sedimentary rock-originated catena. Determination coefficients of PTFs were 0.31 for A horizon, 0.25 for B, and 0.35 for C with all data set while those were 0.74 for A, 0.48 for B, and 0.54 for C. Organic matter was a dominant factor affecting Ks in A horizon but clay content was selected as the only factor influencing Ks in C horizon. It implies that PTFs should be developed with understanding characteristics of parent materials and horizons. Developed PTFs for granite- or gneiss-originated catena were following: A horizon: Log ($K_s{\times}10^7$) = -0.031C + 0.398OM + 3.49 B horizon: Log ($K_s{\times}10^7$) = -0.028C + 0.141OM + 4.05 C horizon: Log ($K_s{\times}10^7$) = -0.072C + 4.66 where C is clay separate (%) and OM is organic matter content ($g\;kg^{-1}$). The unit of Ks is cm $sec^{-1}$.