• Journal of the Korean Geotechnical Society
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• v.28 no.2
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• pp.57-70
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• 2012

For soft ground, a pile foundation is typically used as a substructure of transmission tower. However, differential settlement between the foundations can cause structural damage of transmission tower. The connected-pile foundation is a type of group foundation consisting of four foundations connected with beams, and it was suggested in USA and Japan. In this study, a series of 1/8 scale model pile tests were performed to investigate the effect of load direction and stiffness of connecting beam on the responses of connected-pile foundation. As a result, the load capacities of the connected-pile foundation were larger than those of the conventional group pile foundation. For example, under the given test conditions in this paper, the resistibility against differential settlement was improved significantly for connected-pile foundation and its efficiency was maximized when the stiffness of connecting beams is about 25% of the mat foundation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.12
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• pp.3265-3276
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• 1996

The studies of document recongnition have been focused mainly on Korean documents. But most of documents composed of Korean and other characters. So, in this paper, we propose the document recognition system that can recognize the multi-size, multi font and mixed type characters. We have utilized a large scale network model, "CombNET" which consists of a 4 layered network with combstructure. And we propose recognition method that can recognize characters without discrimination of character type. The first layer constitutes a Kohonen's SOFM network which quantizes an input feature vector space into several sub-spaces and the following 2-4 layers constitutes BP network modules which classify input data in each sub-space into specified catagories. An experimental result demonstrated the usefulness of this approach with the recognition rates of 95.6% for the training data. For the mixed type character documents we obtained the recognition rates of 92.6% and recognition speed of 10.3 characters per second.

• Journal of Hydrogen and New Energy
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• v.29 no.1
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• pp.41-55
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• 2018

General polymer electrolyte fuel cell (PEMFC) operates at less than $80^{\circ}C$. Therefore liquid phase water resulting from electrochemical reaction accumulates and floods the cell which in turn increases the mass transfer loss. To prevent the flooding, it is common to employ serpentine flow channel, which can efficiently export liquid phase water to the outlet. The major drawback of utilizing serpentine flow channel is the large pressure drop that happens between the inlet and outlet. On the other hand, in the high temperature polymer electrolyte fuel cell (HT-PEMFC), since the operating temperature is 130 to $180^{\circ}C$, the generated water is in the state of gas, so the flooding phenomenon is not taken into consideration. In HT-PEMFCs parallel flow channel with lower pressure drop between the inlet and outlet is employed therefore, in order to circulate hydrogen and air in the cell less pumping power is required. In this study we analyzed HT-PEMFC's different flow channels by parallel computation using previously developed 3-D isothermal model. All the flow channels had an active area of $25cm^2$. Also, we numerically compared the performance of HT-PEMFC parallel flow channel with different manifold area and Rib interval against the original serpentine flow channel. Results of the analysis are shown in the form of three-dimensional contour polarization curves, flow characteristics in the channel, current density distribution in the Membrane, overpotential distribution in the catalyst layer, and hydrogen and oxygen concentration distribution. As a result, the performance of a real area fuel cell was predicted.

• KSBB Journal
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• v.31 no.4
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• pp.193-199
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• 2016

Global warming caused from the heavy consumption of fossil fuel is one of the biggest problems to be solved. Biofuel has been gained more attention as an alternative to reduce the consumption of fossil fuel. Recently, butanol produced from the genus Clostridium has been considered as one of the promising alternatives for gasoline, fossil based fuel. Nevertheless, the lack of the genome-engineering tools for the genus Clostridium is the major hurdle for the economic production of butanol. More recently, genome engineering tools have been developed for metabolic engineering of butanol-producing Clostridium species, which includes genome scale network model and genome editing tools on the basis of mobile group II introns and CRISPR/Cas system. In this study, the genome engineering tools for butanol-producing Clostridium species have been reviewed with a brief future perspective.

• Research in Community and Public Health Nursing
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• v.31 no.2
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• pp.179-188
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• 2020

Purpose: The purpose of this study is to identifying factors influencing organizational commitment of nurses in Korean Red Cross Blood Center (KRCBC). Methods: A cross sectional survey was conducted for 224 nurses who worked for more than three months in KRCBC. Data were collected using a structured questionnaire from August 28 to September 20, 2018. Data were analyzed using independent t-test, Mann-Whitney U test, one-way ANOVA, Pearson's correlation coefficient, and hierarchical multiple regression analysis with SPSS (ver. 23.0). Results: The mean score of organizational commitment was 3.37±0.52 on a scale of 5 points, the mean of positive psychological capital was 3.51±0.51, communication ability score was 3.60±0.48, and social support score was 3.68±0.57. The factors influencing organizational commitment of nurses in KRCBC were social support (β=.41, p<.001), job satisfaction (β=.27, p<.001), and total length of employment in KRCBC (β=.19, p=.016). The model explained 36.1% of the organizational commitment of the nurses. Conclusion: It is necessary to develop an organizational commitment program for strengthening social support and job satisfaction to improve organizational commitment of nurses in KRCBC. Such a program is eventually expected to improve the quality of nursing care of nurses with a short career in KRCBC.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.48 no.3
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• pp.25-33
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• 2011

As chip operating frequency increases, there is growing concern about on-chip interconnect inductance. This paper presents a two-step inductance screening tool to select interconnects with significant inductance effects in a VLSI design. Test chips designed in different CMOS technology nodes are examined. The inductance screening results show that 0.1% of the nets in a design have inductance problems with chips running at its operating frequency, supporting the necessity of a screening process instead of adding inductance model to all the nets in the design. The increase in resistance due to geometry scaling will strongly affect the significance of inductance on delay as technology and frequency scale. Since higher frequency worsens inductance problem and geometry scaling alleviates it, inductance screening tool can provide useful guidelines to circuit designers.

• Journal of IKEEE
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• v.22 no.2
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• pp.420-426
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• 2018

In the near future, CNTFET(Carbon NanoTube Field Effect Transistor) is considered as one of the most promising candidate for the replacement of modern silicon-based transistors by utilizing the ballistic or near-ballistic transport capability of CNT(Carbon NanoTube). For the large-scale fabrication of high performance CNTFET, semiconducting CNTs have to be well-aligned with a fixed pitch and high densities in the each CNTFET. However, due to the immaturity of the CNTFET fabrication process, CNTs can be unevenly positioned in a CNTFET and existing HSPICE library file cannot support the circuit level evaluation of performance variation caused by the unevenly positioned CNTs. To evaluate the performance variation, linear programming methodology was suggested previously, but the errors can be made during the calculation of the current and the gate capacitance of a CNTFET. In this paper, the reasons causing errors will be discussed in detail and the new methodology to reduce the errors will be also suggested. Simulation results shows that the errors can be reduced from 7.096% to 3.15%.

• Journal of Environmental Science International
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• v.15 no.1
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• pp.9-19
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• 2006

The purpose of this research is development of radar data assimilation observed at Jindo S-band radar The accurate observational data assimilation system is one of the important factors to meteorological numerical prediction of the region scale. Diagnostic analysis system LAPS(Local Analysis and Prediction System) developed by US FSL(Forecast Systems Laboratory) is adopted assimilation system of the Honam district forecasting system. The LAPS system was adjusted in calculation environment in the Honam district. And the improvement in the predictability by the application of the LAPS system was confirmed by the experiment applied to Honam district local severe rain case of generating 22 July 2003. The results are as follows: 1) Precipitation amounts of Gwangju is strong associated with the strong in lower level from analysis of aerological data. This indicated the circulation field especially, 850hPa layer, acts important role to precipitation in Homan area. 2) Wind in coastal area tends to be stronger than inland area and radar data show the strong wind in conversions zone around front. 3) Radar data assimilation make the precipitation area be extended and maximum amount of precipitation be smaller. 4) In respect to contribution rate of different height wind field on precipitation variation, radar data assimilation of upper level is smaller than that of lower level.

• Journal of Environmental Science International
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• v.15 no.5
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• pp.417-430
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• 2006

We focused on improvement in simulation of wind fields for the complex coastal area. Local Analysis and Prediction System(LAPS) was used as a data assimilation method to improve initial conditions. Case studies of different LAPS inputs were performed to compare improvement of wind fields. Five cases have been employed : I) non data assimilation, II) all available data, III) AWS, buoy, QuikSCAT, IV) AWS, buoy, wind profiler, V) AWS, buoy, AMEDAS. Data assimilation can supplement insufficiency of the mesoscale model which does not represent detailed terrain effect and small scale atmospheric flow fields. Result assimilated all available data showed a good agreement to the observations rather than other cases and estimated veil the local meteorological characteristics including sea breeze and up-slope winds. Result using wind profiler data was the next best thing. This implies that data assimilation with many high-resolution sounding data could contribute to the improvements of good initial condition in the complex coastal area. As a result, these indicated that effective data assimilation process and application of the selective LAPS inputs played an important role in simulating wind fields accurately in a complex area.

• Journal of the Korean earth science society
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• v.32 no.1
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• pp.46-56
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• 2011

The purpose of this paper is to evaluate the wind energy resources with high spatial resolution in Sunghak and Guduck mountains in Busan Metropolitan area under the various atmospheric stabilities. The numerical model used in this research is A2C (Atmosphere to CFD), mainly applied to assess the regional scale and microscale meteorological phenformin. Wind under the strong atmospheric stability moves around mountain side smoothly due to the strong potential energy. On the other hand, the cavity region on the lee side of mountain tends to be created and expanded as the atmospheric stability decrease. Annually the average distribution of wind power density, turbulence kinetic energy, and vertical wind shear help to explain quantitatively that wind resource near the northern side of Guduck mountain top is more suitable to establish wind energy complex than that in any other regions in the target area.