• Proceedings of the SAREK Conference
• /
• 2008.11a
• /
• pp.80-83
• /
• 2008

As SOC (Social Overhead Capital) has been expanded, the highway road construction has been accelerated and city road system has been more complicated. So, long road tunnels have been increased and traffic flow rate also has been raised. Accordingly, the exhausting gas of vehicle cars seriously deteriorates the tunnel inside air quality and driving view. In order to improve tunnel inside air quality, we may need to introduce a compulsory ventilation system as well as natural ventilation mechanism. The natural ventilation mechanism is enough for short tunnels, meanwhile longer tunnels require a specific compulsory ventilation facility. Many foreign countries already have been devoting on development of effective tunnel ventilation system and especially, some European nations and Japan have already applied their developed tunnel ventilation system for longer road tunnels. More recently, as the quality of life improved, our concerns about safety of driving and better driving environment have been increased. In order to obtain clearer and longer driving view, we are more interested in EP tunnel ventilation system in order to remove floating contaminants and automobile exhaust gas. Evan though it's been a long time since many European countries and Japan applied more economical and environment-friendly tunnel ventilation system with their self-developed Electrostatic Precipitator, we are still dependant on imported system from foreign nations. Therefore, we need to develop our unique technical know-how for optimum design tools through validity investigation and continuous possibility examination, eventually in order to localize the tunnel ventilation system technology. In this project, we will manufacture test-run products to examine the performance of system in order to develop main parts of tunnel ventilation system such as electrostatic precipitator, high voltage power generator, water treatment system, etc.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.39 no.11
• /
• pp.33-43
• /
• 2002

This paper describes a design of cryptographic processor that implements the AES (Advanced Encryption Standard) block cipher algorithm "Rijndael". To achieve high throughput rate, a sub-pipeline stage is inserted into a round transformation block, resulting that two consecutive round functions are simultaneously operated. For area-efficient and low-power implementation, the round transformation block is designed to share the hardware resources for encryption and decryption. An efficient on-the-fly key scheduler is devised to supports the three master-key lengths of 128-b/192-b/256-b, and it generates round keys in the first sub-pipeline stage of each round processing. The Verilog-HDL model of the cryptoprocessor was verified using Xilinx FPGA board and test system. The core synthesized using 0.35-${\mu}m$ CMOS cell library consists of about 25,000 gates. Simulation results show that it has a throughput of about 520-Mbits/sec with 220-MHz clock frequency at 2.5-V supply.

• International Area Studies Review
• /
• v.15 no.2
• /
• pp.151-173
• /
• 2011

The purpose of this paper is to examine the impact of production factors on economic growth in China during 1979~2008. In order to grasp the determinant and contribution analysis, we take fixed effect model and random effect model and Hausman test to choice model. The results show that the finance variable (rsav) and SOC variable (rsoc) have negative effects on the economic growth in the long run except some models. But unimproved raw labor variable (rlab), physical capital variable (rcap) and education variable (redu) shows strongly positive effect for the same time. We found the meaning of coefficients of growth factors. relative contribution of each input to per-capita growth in China. The direct elative contribution of physical investment to per-capita growth gives 35.9 percent in total model (TMO) and unimproved raw labor contributes only 4.7 percent. In all modes, physical investment (rcap) was the most important contributor of predicted growth in China economy.

• The Journal of the Acoustical Society of Korea
• /
• v.41 no.2
• /
• pp.210-217
• /
• 2022

Passive source depth estimation has been studied for decades since the source depth can be used for target classification, target tracking, etc. The purpose of this paper is to solve the problem of ambiguity in the previous paper [S.-il. Cho et al. (in Korean), J. Acoust. Soc. Kr. 38, 120-127 (2019)] that source depth is estimated in two points. The patterns of phase shift of Channel Impulse Response(CIR) reflected in ocean surface and bottom is used for removing ambiguity of the source depth estimation, and after removing ambiguity, source depth is estimated at one point through the intersection of CIR. In order to extract CIR in case of unknown source signal and continuous signal or noise, Ray-based blind deconvolution is used. The proposed algorithm is demonstrated through numerical simulation in ocean waveguide.

• Childhood Kidney Diseases
• /
• v.5 no.2
• /
• pp.156-163
• /
• 2001

Purpose We performed urinary mass screening(UMS) program for 2,804 children of second grade elemantary school 8 years of age in Paju city with cooperation of Paju City Health Center to determine the prevalence of asymptomatic proteinuria and hematuria, and to estimate the risk of incipient renal diseases. Also we attempted to evaluate the significance of hematuria in UMS in addidtion to proteinuria. Methods : 2,804 children of the 2nd grade of elementary school who lived in Paju city were included to our UMS program in 2000. They were constituted with 1,428 boys and 1,376 girls. The screening program was carried out in 3 steps The 1st screenig test was performed at schools and then students with abnormal results were examined repeatedly at Paju City Health Center and our hospital. Those students who showed proteinuria and/or hematuria in the 1st and 2nd test were referred to our hospital to undertake the 3rd close examination including physical examination, laboratory tests and radiologic tests. Results : (I) The prevalence of urinary abnormality in the 1st screening test was $8.3\%$(233 students), comprised of $5.9\%$ of boys, $10.8\%$ of girls. (2) Among 2,804 children tested in the first screening, prevalences of asymptomatic proteinuria and isolated hematuria were 64($2.3\%$), 163($5.8\%$) respectively, and the prevalence of proteinuria with hematuria was 6($0.2\%$). (3) Among 233 students with urinary abnormalities at the 1st screening test, 102 students applied to the 2nd test. 32 children, about one third of them, were also found to have abnormal urinary findings ; isolated hematuria 30, proteinuria with hematuria 2. (4) Those findings of clinical evaluation for children with isolated hematuria at the hospital showed as follows: idiopathic isolated microscopic hematuria 21, normal 6, urinary tract infection 1, idiopathic hypercalciuria 1 and simple renal cyst 1. Those 2 students with proteinuria and hematuria seemed to have chronic glomerulonephritis. Conclusion : (1) The clinical evaluation for children who showed positive results at the 1st screening test should be done judiciously. Because of high false positive rate, almost who showed positive results was normal, only a few of them had pathologic conditions. In this study, actual incidence of incipient renal diseases in children of 8 year old was calculated to be $0.4\%$. (2) The definite conclusion whether a urinary mass screening test can alter the prognosis of incipient renal diseases could not be drawn with this study. Further study must be necessary (3) We could acknowledge the significance of hematuria in UMS, but it is necessary that one should be judicious in managing and follow-up those that show abnormal results. (J Korean Soc Pediatr Nephrol 2001;5 : 156-63)

• Childhood Kidney Diseases
• /
• v.5 no.1
• /
• pp.15-21
• /
• 2001

Purpose : Urinary tract infections (UTIs) of children require prompt and correct diagnosis and treatment to reduce the risk of renal damage. As a first step to improve the outcome of UTI in Korea, we investigated the practical variations in the methods of diagnosis, treatment, and evaluation of children with UTI and UTI prevention. Method :A questionnaire related to the individual policy on UTI diagnosis. treatment, imaging test, and prevention was submitted to 26 experts. Result Majority of the experts used bag-collected urine specimen for infants and mid-stream urine specimen for children for urinary culture. With a negative result of culture study, they diagnosed UTI when there was pyuria, positive results of the nitrite test, or bacteriuria. 80 $\%$ of experts prescribed prophylactic antibiotics after upper tract UTI. Operative treatment of vesicoureteral reflux (VUR) was indicated for children older than one or two years old with high-grade VUR, refractory breakthrough infections, or recurrent UTIs. Most of them performed kidney ultrasonography on the diagnosis of UTI and more than half of them evaluated children treated of UTI with vesicocystourethrogram and/or DMSA scintigraphy. Majority did not recommend circumcision. Half of the experts were screening siblings of VUR patients. Conclusion : Considering the variations exposed through this study systematic guidelines for management of children with UTI in Korean would be necessary. (J. Korean Soc Pediatr Nephrol 5 : 15-21, 2001)

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.17 no.3
• /
• pp.383-392
• /
• 2015

In subsea tunnelling, prediction of the fractured zone (or water bearing zone) ahead of tunnel face saturated by seawater with high water pressure has been a key factor for safe construction. This study verified the feasibility of utilizing induced polarization (IP) survey at tunnel face for predicting the ground condition ahead of the subsea tunnel face. A pore model was proposed to compute chargeability in granular material, and the relationship correlating chargeability with the variables affecting the chargeability was derived from the model. Parametric study has been performed on the variables to figure out the most influential factors affecting the chargeability. The results of the parametric study show that the size of narrow pores ($r_1$) and the salinity of pore water are the most influential factors on chargeability. Laboratory tests were conducted on various types of ground condition by changing the salinity of pore water, the thickness of the fracture zone and the existence of gouge (weathered granite) within the joints of the fractured zone to figure out the effect of the ground characteristics on the IP phenomenon. Test results show that the chargeability of the fractured zone saturated by seawater increases if the joints in the fractured zone are filled with gouge since the infilled gouge will decrease the size of narrow pores ($r_1$).

• Journal of the Korea Concrete Institute
• /
• v.25 no.6
• /
• pp.621-630
• /
• 2013

Several techniques for steel corrosion detection are proposed and HCP (half cell potential) technique is widely adopted for field investigation. If concrete has cracks on surface, steel corrosion is rapidly accelerated due to additional intrusion of chloride and carbon dioxide ions. This study is for an evaluation of HCP in cracked concrete exposed chloride attack. For this work, RC (reinforced concrete) beams are prepared considering 3 w/c ratios (0.35, 0.55, and 0.70) and several cover depths (10~60 mm) and various crack widths of 0.0~1.0 mm are induced. For 35 days, SST (salt spraying test) is performed for corrosion acceleration, and HCP and corrosion length of rebar are evaluated. With increasing crack width, w/c ratios, and decreasing cover depth, HCP measurements increase. HCP evaluation technique is proposed considering the effects of w/c ratios, crack width, and cover depth. Furthermore anti-corrosive cover depths are obtained through Life365 program and the results are compared with those from this study. The results shows relatively big difference in cracked concrete, however provide similar anti-corrosive conditions in sound concrete.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.5
• /
• pp.559-568
• /
• 2019

Recently, the infrastructure of the marine environment has been increasing. Therefore, there has been increasing interest in increasing the durability of structures. The FRP Hybrid Bar with improved durability against corrosion was developed in recent years. On the other hand, studies that evaluate the corrosion resistance are insufficient. In this study, the corrosion resistance according to the type of rebar in concrete was assessed and analyzed. The experiment used steel bars and FRP Hybrid Bar. The corrosion test method was a galvanic current and half-cell potential method. The accelerated corrosion test was carried out by four levels (0%, 1.5%, 3%, and 6%) of chloride added to the concrete. The galvanic current measurements revealed no corrosion current in the FRP Hybrid Bar. The half-cell measurement also showed the corrosion resistance of the FRP Hybrid Bar. Therefore. FHB can be used as an alternative steel for structures where a marine environment and steel corrosion are predicted.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.16 no.2
• /
• pp.149-160
• /
• 2014

The objective of this study is the application of the harmony search (HS) algorithm and verification of the accuracy of inverse analysis to predict the location, thickness and electrical properties of anomalous zone ahead of tunnel face when utilizing the electrical resistivity survey using electrical resistivity of the ground. The relationship correlating the characteristic values of the anomalous zone with the electrical resistance values was derived using Gauss' laws and Ohm's laws. Inverse analysis program was developed to predict anomalous zone by using electrical resistivity based on HS algorithm. Electrical resistance measuring system is devised to obtain the electrical resistivity of the ground, and laboratory tests were performed on anomalies to verify the proposed HS algorithm. The test results show that the characteristics of the anomalies are predicted reasonably well resulting in less than 5% error when predicting the location and thickness of the anomaly.