• Korean Chemical Engineering Research
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• v.45 no.3
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• pp.242-248
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• 2007

For an optimal design of automotive electric system, it is important to have a reliable modeling tool to predict the charge-discharge behaviors of the automotive battery. In this work, a two-dimensional modeling was carried out to predict the charge-discharge behaviors of a 12-V automotive lead-acid battery. The model accounted for electrochemical kinetics and ionic mass transfer in a battery cell. In order to validate the modeling, modeling results were compared with the experimental data of the charge-discharge behaviors of a lead-acid battery. The discharge behaviors were measured with three different discharge rates of C/5, C/10, and C/20 at operating temperature of $25^{\circ}C$. The batteries were charged with constant current of 30A until the charging voltage reached to a predetermined value of 14.24 V and then the charging voltage was kept constant. The discharge and charge curves from the measurements and modeling were in good agreement. Based on the modeling, the distributions of the electrical potentials of the solid and solution phases, the porosity of the electrodes, and the current density within the electrodes as well as the acid concentration can be predicted as a function of charge and discharge time.

• Journal of the Korean GEO-environmental Society
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• v.11 no.12
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• pp.47-56
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• 2010

The construction of new roads and the consistent extension of already-existing roads or the line-shape revision of those roads are increased with the governmental investment to SOC facilities currently. Accordingly, the road cut slopes are in the trend of rapidly increasing. As the road slope has increased, a lot of human and property damages has entailed consequently and in the local case, numerous studies have carried out aiming at minimizing this damages caused by the rockfall and landslide. In general, standard falling rock prevention facility has employed for most of the local road slope based on "Guide for Installation and Management of Road Safety Facilities" published by MLTM(the Ministry of Land, Transport, and Maritime Affairs) but profound doubt has raised as to whether this rockfall prevention facility would function properly enough to prevent rockfall efficiently without any damages in case of actual occurrence of rockfall. In addition, it is a reality that in most cases, such work is relied on overseas technology as a whole as the local technical level is low and in case of rockfall prevention net, it is judged that a study on rockfall prevention net that is able to endure more powerful rockfall energy is required as the problem including net bursting is taken place as a result of enough bearing force being failed to be demonstrated due to its partial weak point(not uniformly made). Under this background, in this study, three kinds of model depending on mesh size of expanded metal that is considered to have an adoptability as rockfall prevention net, as target are selected and characteristics depending on mesh size of expanded metal is intended to be researched through a pull-out test performance by using pull-out test equipment rockfall prevention net.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.1
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• pp.1-10
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• 2011

This study was performed for the purpose of reviewing the strategic management direction and ideas of the policy for Seoul City's Hangang Renaissance. In order to accomplish this, levels were established for each step of the policy and the policy priority by level was derived. The policy priority by level was analyzed by a decision making model through the Analytic Network Process(ANP) and the priority would be the standard to judge the order of priority. The analysis results showed that there was not a big difference between the priorities of two basic concepts: restoration and creation. The fourth level, detail plan of the third level, showed priority that development by type for waterside city in case of reorganizing city space and diversification of land utilization, utilization of riverside space in water front town for public and composit purpose, establishment of comprehensive plan on constructions in case of improving the landscape of Hangang and unified design plan rose to important element in case of forming Hangang park with the me. Based on the results of priority analysis, we would like to propose for the direction about the policy on Hangang Renaissance project, the policies forming Hangang Park with theme through unified design plan and reorganizing city space have to be proceed preferentially and connected with other plans.

• Journal of Practical Engineering Education
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• v.8 no.2
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• pp.111-120
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• 2016

Education equipment for field programmable gate array (FPGA) design of sensor-based IOT (Internet Of Thing) system is introduced. Because sensors have different interfaces, several types of interface controller on FPGA need. Using this equipment, several types of interface controller, which can control ADC (analog-to-digital converter) for analog sensor outputs and $I^2C$ (Inter-Integrated Circuit), SPI (Serial Peripheral Interface Bus), and GPIO (General-Purpose Input/Output) for digital sensor outputs, can be designed on FPGA. Image processing hardware using image sensors and display controller for real and image-processed images or videos can be design on FPGA chip. This equipment can design a SOC (System On Chip) consisting of a hard process core on Linux OS and a FPGA block for IOT system which can communicate with wire and wireless networks. Using the education equipment, an example of hardware design using image sensor and accelerometer is described, and an example of syllabus for "Digital system design using FPGA" course is introduced. Using the education equipment, students can develop the ability to design some hardware, and to train the ability for the creative capstone design through conceptual, partial-level, and detail designs.

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

• Childhood Kidney Diseases
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• v.7 no.2
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• pp.189-196
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• 2003

Purpose : Ureteral duplication is a common urologic anomaly and early diagnosis may prevent irreversible renal damage. We thus aimed to evaluate the benefits of prenatal sonography in early detection. Methods : We retrospectively studied 55 children with duplicated systems who were admitted to Severance Hospital, Yonsei University, Seoul, Korea from January 1998 to July 2003. Results : The mean age at diagnosis was 2.3 years old. 89% of the children had complete duplicated ureter. 47% of the children visited the hospital with an initial complaint of abnormal prenatal sonographic findings. Among these patients, 70.8% had DMSA defects. The mean differential renal function(DRF) in the DMSA scan was 48.2% in the group diagnosed prenatally. In the postnatally-diagnosed group, DMSA defects were found in 67.7% patients and the mean DRF was 45.5%. Conclusion : In comparison with the past studies, the mean age at diagnosis is becoming younger, and the proportion of abnormal prenatal sonography as an initial complaint larger. Other clinical manifestations were similar. The difference of the renal damage between the prenatally diagnosed group and the postnatally diagnosed group was not statistically significant. A multi-center study may help to prove the importance of prenatal sonography in early diagnosis and treatment of ureteral duplication. (J Korean Soc Pediatr Nephrol 2003;7:189-196)

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.1
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• pp.36-42
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• 2007

Korean paddy soils have long been almost uniformly managed throughout the whole country with flooded, deep tillage, puddlling, transplanting, and uncovering after harvest. Management of soil organic carbon could be more important in the sources of green house gases. However, soil organic carbon dynamics were not been studied for Korean paddy soils. Therefore, we evaluated the changes in soil organic carbon (SOC) of paddy soils between 1999 and 2003 at the same locations nationwide except islands. Soil organic carbon tends to increase in Inceptisols, which is predominant soil order for Korean paddy soils, from 1999 to 2003. Soil organic carbon increases in topographically plain paddy soils was greater than in valley soils, and was considerably high in predominant types of paddy soils (i.e., well adapted paddy soils, sandy paddy soils, and poorly drained paddy soils) but low and stable in the saline paddy soils. We also found that clay paddy soils are greater in soil organic carbon than sandy paddy soils. Through this study, we concluded that a proper management of paddy soils could contribute to soil organic carbon storage, which imply that the Korean paddy soils could help to enhance carbon dioxide sequestration via soil organic matter into the soil.

• Land and Housing Review
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• v.12 no.2
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• pp.109-120
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• 2021

Global warming due to increased carbon dioxide is perceived as one of the factors threatening the future. Efforts are being made to reduce carbon dioxide emissions in each industry around the world. In particular, environmental loads and impacts during the life cycle of SOC structures and buildings have been quantitatively assessed through a quantitative method called Life Cycle Assessment (LCA). However, the construction sector has gone through difficulty in quantitative assessment for several reasons: 1) LCI DB is not fully established; 2) the life cycle is very long; 3) the building structures are unique. Therefore, it takes enormous effort and time to carry out LCA. Rather than estimating carbon emissions with accuracy, this study aims to present a simplified estimation model that allows owners or designers to easily estimate carbon dioxide emissions with little effort, given that rapid and rough decisions regarding environmental load reduction are to be made. This study performs the LCA using data from 25 road construction projects across the country, followed by multiple regression analyses to derive a simplified carbon estimation model (SLCA). The study also carries out a comparative analysis with values estimated by performing a typical LCA. The comparison analysis shows an error rate of less than 5% for 16 road projects.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.559-568
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• 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 Platform Technology
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• v.11 no.2
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• pp.54-65
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• 2023

Due to the nature of electric vehicles, the batteries used for electric vehicles have a very large rated capacity. If an electric vehicle runs for a long time or an electric vehicle is abandoned due to a traffic accident, the electric vehicle battery becomes a waste battery. Even in vehicles that are being abandoned, the remaining capacity of waste batteries for electric vehicles is sufficient for other purposes. Waste batteries for automobiles are very expensive, so they need to be recycled and reused, but there was a problem that the standards for measuring the performance grade of waste batteries for recycling and reuse were insufficient. As a method for measuring the remaining capacity of waste battery, the most stable and reliable method is to measure the remaining capacity of battery using full charge and discharge. However, the inspection method by the full charging and discharging method varies depending on the capacity of the battery, but it takes more than a day to inspect, and many people are making great efforts to solve this problem. In this paper, an electric vehicle battery residual capacity analysis technique using voltage deviation between cells was studied and analyzed as a method to reduce inspection time for electric vehicle batteries. To this end, a full charging and discharging-based capacity measurement system was constructed, experimental data were collected using a nose or waste battery, and the correlation between the voltage deviation and the remaining capacity of the battery pack was analyzed to verify whether it can be used for battery inspection.