• Journal of the Korean GEO-environmental Society
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• v.13 no.2
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• pp.41-47
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• 2012

The purpose of this study was to determine optimum condition for the cultivation of Chlorella sp. FC-21 using red light emitting diodes (LED). Specific growth rate and cell concentration were measured for the reactors at the illuminations of different light intensity of red LED. Under the illumination of red LED, specific growth rate increased as light intensity increased but cell concentrations decreased. To determine beneficial effect of aeration to cell cultivation, micro-air bubbles were aerated at 0.7 vvm in the reactor at the illumination of red LED. Two and ten times greater specific growth rate and cell concentration were obtained when aeration was applied. In case of blowing of carbon dioxide, pH of culture medium decreased below to pH 3, which resulted in decreases of cell concentration. From this study, we found that red LED with aeration were the most appropriate light source for the cultivation of Chlorella sp. FC-21.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2601-2610
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• 2013

The main limiting factors of Precise Point Positioning(PPP) accuracy are errors in broadcast satellite orbits, clock errors, and the others, which are receiver-dependent errors(ionospheric, tropospheric refraction, multipath, and tides, etc.). Therefore, to facilitate high precision PPP, precise orbits/clocks corrections, the receiver-dependent errors corrections have to apply to multi frequency GNSS measurements for an ionosphere free combination and integer ambiguity resolution in real-time. Currently, there are many Analysis Centers, which offer the precise corrections stream computed in real-time using the global or regional GNSS tracking network. The goles of this research considered performances of the real-time static PPP with using RTCM corrections from NTRIP casters. For this, the corrections streams of Analysis Centers received via NTRIP does apply to GNSS data of check points individually, as well as jointly, in accordance with various session lengths. After that, have compared the PPP results from the corrections streams with each other, and with Standard Point Positioning(SPP) results.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.523-526
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• 2002

The crosstalk among coupled microstrip lines is the major limiting factors of signal qualities in the high-speed digital and communication equipment. In this paper, a three-dimensional finite difference time domain (FDTD) method is applied to analyze the crosstalk between the coupled microstrip lines. The proposed structures of the coupled microstrip lines are investigated to reduce the coupling in a simple way by modifying their ground plane with an optimum gap. The examples of these structures with the different sizes of the gaps on their ground plane are studied. These structures are considered as the four-port network to evaluate transmission efficiency, near- and far-end crosstalk. Gaussian pulse is excited to evaluate the frequency characteristics from dc to 30 ㎓. The transmission efficiency, near- and far-end crosstalk of each structure of the coupled microstrip lines are demonstrated. The numerical results of this study show that the majority of crosstalk is the far-end crosstalk. The usage of the optimum gap on the ground plane can reduce the far-end crosstalk of the coupled microstrip lines while the transmission efficiency is nearly equal.

• Geomechanics and Engineering
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• v.11 no.2
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• pp.235-252
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• 2016

This paper presents a new numerical solution of the ultimate lateral capacity of rectangular piles in clay. The two-dimensional plane strain finite element was employed to determine the limit load of this problem. A rectangular pile is subjected to purely lateral loading along either its major or minor axes. Complete parametric studies were performed for two dimensionless variables including: (1) the aspect ratios of rectangular piles were studied in the full range from plates to square piles loaded along either their major or minor axes; and (2) the adhesion factors between the soil-pile interface were studied in the complete range from smooth surfaces to rough surfaces. It was found that the dimensionless load factor of rectangular piles showed a highly non-linear function with the aspect ratio of piles and a slightly non-linear function with the adhesion factor at the soil-pile interface. In addition, the dimensionless load factor of rectangular piles loaded along the major axis was significantly higher than that loaded along the minor axis until it converged to the same value at square piles. The solutions of finite element analyses were verified with the finite element limit analysis for selected cases. The empirical equation of the dimensionless load factor of rectangular piles was also proposed based on the data of finite element analysis. Because of the plane strain condition of the top view section, results can be only applied to the full-flow failure mechanism around the pile for the prediction of limiting pressure at the deeper length of a very long pile with full tension interface that does not allow any separation at soil-pile interfaces.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.2 s.344
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• pp.42-50
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• 2006

Owing to the development of semiconductor processing technology, high density complex circuits can be integrated in a System-on-Chip (SoC). However, increasing energy consumption becomes one of the most important limiting factors. Power estimation at the early stage of design is essential, since design changes at lower levels may significantly lengthen the design period and increase the cost. In this paper, logic level circuits ire levelized and several levels are selected to build power model tables for efficient power estimation. The proposed techniques are applied to a set of ISCAS'85 benchmark circuits to illustrate their effectiveness. Experimental results show that significant improvement in estimation accuracy and slight improvement in efficiency are achieved when compared to those of a well-known existing method. The average estimation error has been reduced from $9.49\%\;to\;3.84\%$.

• The Plant Pathology Journal
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• v.18 no.2
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• pp.81-84
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• 2002

Effects of temperature and dew period on sporulation of a mycoherbicide, Epicoccosorus nematosporus, on the lesion of its host, Eleocharis kuroguwai were determined. Conidia formation was first observed after 10 days on plants incubated for either 12 or 16 h in a dew chamber at 28$^{\circ}C$; 16 h dew period resulted in more conidia formation. As the dew period was decreased to less than 8 h, fewer conidia formed. Conidial production was most abundant at 28$^{\circ}C$ and produced as much as 3.3$\times$10$^4$conidia per lesion, while 0.1$\times$10$^3$and 2.3$\times$10$^3$conidia per lesion were produced at 16$^{\circ}C$ and 36$^{\circ}C$, respectively. Alternating temperature regimes, i.e., 30/15, 30/20, 28/20, and 28/15$^{\circ}C$ (day/night) were much better than constant temperature, i.e., 30/30, 28/28/, and 20/2$0^{\circ}C$ for sporulation. In the second sporulation, there were as much as 3.1$\times$10$^4$conidia per lesion (ca. <50% of the first sporulation). Then, sporulation dropped sharply to 6.2$\times$10$^2$conidia per lesion in the third sporulation. Results of this study suggest that temperature combined with dew period is the primary limiting factor in the use of E. nematosporus as a mycoherbicide off, kuroguwai.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.16 no.2
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• pp.89-94
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• 2013

Purpose: The aim of this study was to evaluate the prevalence of increased aminotransferase levels and to identify associated factors in children admitted to hospital with urinary tract infections (UTIs). Methods: The study included children with a diagnosis of UTI who were admitted to the Konyang University Hospital from January 2007 to May 2011. The total number of patients was 249 and the mean age was $15.88{\pm}28.21$ months. UTI was defined as a positive urine culture (> $10^5$/colony forming unit [CFU]) with pyrexia. Patients were treated by intravenous antibiotics, such as ampicillin/sulbactam, aminoglycoside, cephalosporins or vancomycin. Patients with neonatal jaundice or other liver disease were excluded. We investigated the relationship of aminotransferase levels with the type of antibiotic, degree of vesicoureteral reflux (VUR), and causative organisms. Results: Children with increased aminotransferase levels were younger than those with normal levels (p=0.001), but white blood cell count, platelet count, causative organisms, type of antibiotics and presence of VUR were not associated with aminotransferase levels. Aminotransferase levels became normal within 1 month after discharge without special measures, except in 1 case. Conclusion: We found that many children with UTI have abnormal aminotransferase levels. In most cases, this change is mild and self-limiting. We conclude that increased aminotransferase level increase during UTI do not require unnecessary tests and excessive treatment.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.8
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• pp.489-493
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• 2017

Microbial fuel cells (MFC) are bio-electrochemical processes that can convert various organic materials present in wastewater into electrical energy. For scaling-up and practical application of MFC, it is necessary to investigate the effect of anode size, electrode distance, and total area of anode on substrate degradation. Spaced electrode assembly (SPA) type microbial fuel cell with multiple anodes treating domestic wastewater was used for simulation. According to computer simulation results, the shorter the distance between electrodes than the size of single electrode, the faster the substrate degradation rate. Particularly, when the total area of the anode is large, the substrate decomposition is the fastest. In this study, it was found that the size of the anode and the distance between the electrodes as well as the cathode electrode, which is known as the rate-limiting step in the design of the microbial fuel cell process, are also important factors influencing the substrate degradation rate.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.3
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• pp.41-49
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• 2000

When sewage and industrial wastewater are treated to improve the coastal water quality, we usually consider the reduction of BOD and/or COD. Due to the inflow of untreated nitrogen and phosphorus, however, the coastal water has eutrophicated. Thus, to improve the water qualify, it is necessary to treat and reduce nitrogen and phosphorus which are the factors limiting algal growth. Hence, with regard to the adaption of Ocean Outfall for the treatment of wastewater in Suyoung Bay, we studied the effectiveness and environmental assessment of Ocean Outfall of which cost is lower than that of advanced treatment, The effectiveness of Ocean Outfall of the second treatment effluent in Nambu S.T.P. was simulated, using the eco-hydrodynamic model as far field model the result showed that the water quality of coastal area receiving wastewater on the surface sea has improved. But the concentrations of nitrogen and phosphorus around the diffuser of Ocean Outfall system can cause many problems on estuary, such as red tide, eutrophication and aquatic toxicity.

• Geophysics and Geophysical Exploration
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• v.16 no.4
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• pp.275-283
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• 2013

The sea dike is the most important facility of reclamation projects, and plays an important role in securing freshwater in the reservoir. Systematic research on practical approaches and data analysis techniques are lacking even though some geophysical methods such as electrical resistivity and self-potential surveys are included within the inspection processes. Hence, geophysical methods were considered for improvement of precision safety diagnosis methods after problems in the maintenance system have been identified, such as safety checks and precision safety diagnoses. In addition, geophysical methods customized according to variations in ambient environmental limiting factors such as pore pressure changes by tidal fluctuation, compaction characteristics of the fill materials, and the surface condition of the embankment were suggested.