• Journal of the Korean Ceramic Society
• /
• v.37 no.8
• /
• pp.817-823
• /
• 2000

A solid-state electrochemicall cell for sensing CO2 gas was fabricated using a solid electrolyte of Li2CO3-Li3PO4-Al2O3 mixture and a reference electrode of LiMn2O4. The e.m.f. (electromotive force) of sensor showed a good accordance with theoretical Nernst slope (n=2) for CO2 gas concentration range of 100-10000 ppm above 35$0^{\circ}C$. The e.m.f. of sensor was constant regardless of oxygen partial pressure at the high temperature above 0.1 atm. It was, however, a little depended on oxygen partial pressure as the pressure decreased below 0.1 atm. The oxygen-dependency of our sensor gradually disappeared as the operating temperature increased. The sensing behavior of our CO2 sensor was affected by the presence of water vapor, but its effect was small comparing with other sensors.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.06a
• /
• pp.83-84
• /
• 2006

In this paper, we examine discharge characteristics of cross-linked polyethylene (since then; XLPE) according to thickness. Voltage was applied to power frequency by step method, and calibration of discharge was set to 50[pC] (slope=8.333). After the voltage was applied, for 10 [sec] (600 [cycle]), occurring discharge and number were detected. Determine of input pattern is difficult because discharge pattern is irregular. Therefore we investigated pattern using the K-means Analysis and Weibull function. Also we investigated variation of centroid and cluster.

• Journal of Navigation and Port Research
• /
• v.45 no.2
• /
• pp.42-53
• /
• 2021

The port space can be considered to be the space in which the characteristics of the port city are best expressed. Also, since it acts as a representative gateway along with the airport, it can have a direct impact on the image of the region and country. However, the harbor hinterland has been a refuge during the war in the past, and it has been concentrating on development related to the port industry; hence, it has a poorer residential environment. Therefore, in this study, in order to ensure equal development in space and equal access to basic urban services, urban design directions were suggested for the harbor hinterland based on the concept of an inclusive city'. To this end, through factor analysis, urban planning elements that can be applied to urban design were derived, and through PLS(Partial Least Square)regression analysis, based on the opinions of residents and experts, urban design directions for the port hinterland were presented. The study site was Gamcheon Port, one of the Busan Ports in Korea, the hinterland of Gamcheon Port was a high slope, and the residential environment was relatively poor due to the dense concentration of older residential areas.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.22 no.3
• /
• pp.156-162
• /
• 2010

When eccentric or inclined load acts on foundation of the port & harbor structures, partial safety factors of bearing capacity limit state were estimated using reliability analysis. Current Korean technical standards of port and harbor structures recommend to estimate the geotechnical bearing capacity using the simplified Bishop method. In practice, however, simple method of comparing ground reaction resistance with allowable bearing capacity has been mostly used by design engineers. While the simple method gives just one number fixed but somewhat convenient, it could not consider the uncertainty of soil properties depending on site by site. Thus, in this paper, partial safety factors for each design variable were determined so that designers do perform reliability-based level 1 design for bearing capacity limit state. For these, reliability index and their sensitivities were gained throughout the first order reliability method(FORM), and the variability of the random variables was also considered. In order to verify partial safety factors determined here, a comparison with foreign design codes was carried out and were found to be reasonable in practical design.

• Journal of Ocean Engineering and Technology
• /
• v.9 no.2
• /
• pp.41-52
• /
• 1995

the necessity of development of the Nearshore zone greatly emphasis in recent years. In the wave deformation model, we can get the wave height and wave direction using the hyperbolic mild slope equation considered the reflection wave. Radiation Stress the driving force of flow was calculated by the Watanabe and Maruyama who proposed on the partial standing wave. In the surf zone, applying the Izumiya and Horikawa's turbulent model considered the bottom friction and energy dissipation, we compared and examined with the Numerical model and Hydraulic test result of Watanabe and Maruyama. This model results obtained for Jin-ha Beach agreed well with the Numerical results. This model is expected so helpful to solve the prediction of the wave deformation problems in the development of the Nearshore zone in the future.

• Proceedings of the IEEK Conference
• /
• 2003.07e
• /
• pp.2020-2023
• /
• 2003

In this paper, our proposed system uses the regional Gabor wavelet and Neural Network to implement face recognition similar to human face recognition system, because the Gator wavelet expresses visual recognition system of human mathematically and the regional Neural Network is robust to white noise and partial illumination. This system consists of two stages of building database and recognizing face. One is composed by using the supervised learning of Neural Network. At this time, the Neural Network is applied to the upper and the lower part of face images respectively. The Backpropagation algorithm is used to learn Neural Network. Another consists of calibration of slope of face image, measurement of illumination variant using deviation with average face image and similarity comparison using Euclidean distance measure.

• Special Issue of the Society of Naval Architects of Korea
• /
• 2005.06a
• /
• pp.134-137
• /
• 2005

Recently, in VLCC, shafting system is stiffer due to large engine power whereas hull structure is more flexible due to scantling optimization, which can be suffered from alignment damage by incompatibility between shafting and hull, In this study, shafting system without stern tube forward bush was adapted for less sensitive system against external factors. Also, shaft alignment analysis was considered with hull deflection at various ship loading conditions and stern tube after bush of long journal bearing was evaluated by static squeezing pressure and dynamic oil film pressure with sloping control. Whirling vibration was also reviewed to avoid resonance with propeller blade order. So, reliable shafting design for VLCC could be achieved through optimized alignment analysis for the system without stern tube forward bush.

• Proceedings of the KSR Conference
• /
• 2002.10a
• /
• pp.601-607
• /
• 2002

Infiltration of rainfall causes railway embankment to be unstable and may result in failure. Basic relationship between the stability of railway embankment and rainfall introducing the partial saturation concept of ground are defined to analyze the stability of embankment by rainfall. A pressure plate test is also peformed to obtain soil-water characteristic curve of unsaturated soils. Based on this curve, the variables in the shear strength function and permeability function are also defined. These functions are used fur the numerical model for evaluation of railway embankments under rainfall. As comparing the model and case studies, the variation of shear strength, the degree of saturation and pore-water pressure for railway embankment during rainfall can be predicted and the safety factor of railway embankment can be expressed as the function of rainfall amount namely rainfall index. Therefore, the research on safety factor on railway embankment considering train speed and rainfall infiltration with the variation of rainfall intensity and rainfall duration was carried out in this paper.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.4 no.4
• /
• pp.1-11
• /
• 2001

This study was carried out to analyze the characteristics of forest environmental and stream morphological factors by using the quantification theory(I) for evaluation of the watershed stability. Present annual mean sediment yield of erosion control dams were investigated in 167 sites of erosion control dam constructed during 1986 to 1999 in Gyeongbuk. The results obtained from this study were summarized as follows; According to the coefficients of partial correlation, each factor affecting to sediment was shown in order of gravel contents, number of first streams order, number of total streams, length of total streams, forest type, length of main stream, parent rock, stand age, soil texture, stream order, slope gradient, soil depth and aspect. Descriptions of class I were as follow; Igneous rock of parent rock, hardwood stands of forest type, less than 20 year of stand age, less than 30cm of soil depth, sandy clay loam of soil texture, more than 41% of gravel contents, south~east of aspect, 2,501~3,500m of length of main stream, 21~25 of number of total streams, 5,501~10,000m of length of total streams, 3 or more than 4 of stream order, more than 16 of number of first stream orders and more than $31^{\circ}$ of slope gradient. Descriptions of class II were as follow; Metamorphic rock of parent rock, coniferous stands of forest type, more than 25 year of stand age, 31~40cm of soil depth, silt loam of soil texture, 11~20% of gravel contents, north~west of aspect, 2,501~3,500m of length of main stream, 16~20 of number of total streams, 3,501~5,500m of length of total streams, 3 of stream order, 11~15 of number of first stream orders and more than $31^{\circ}$ of slope gradient. Descriptions of class III were as follow; Sedimentary rock of parent rock, mixed stands of forest type, more than 25 year of stand age, more than 51cm of soil depth, silty clay loam of soil texture, less than 10% of gravel contents, south~west of aspect, less than 500m of length of main stream, less than 5 of number of total streams, less than 1,000m of length of total streams, less than 1 of stream order, less than 2 of number of first stream orders and less than $25^{\circ}$ of slope gradient. The prediction method of suitable site for erosion control dam divided into class I, II, and III for the convenience of use. The score of class I evaluated as a very unstable area was more than 8.4494. A score of class II was 8.4493 to 6.0452, it was evaluated as a moderate stable area, and class III was less than 6.0541, it was evaluated as a very stable area.

• The Journal of Engineering Geology
• /
• v.14 no.1
• /
• pp.71-80
• /
• 2004

The failure of cut slopes frequently occurs particularly during the thawing season and the rain season in summer. This study interpreted data collected from site to which a real-monitoring system was applied in order to analyze the causes of ground behaviors and to forecast future slope failure. As for research methods, this study analyzed the size and mechanism of failure by integrating the results of field surveys and measurements. Furthermore, it analyzed data transmitted by the monitoring system installed in the a result, three times of ground displacement occurred as well as a number of partial tension cracks. The cut slope composed of sandstone and siltstone started its initial behavior as a result of torrential downpour and the loss of support of the substructure. For quantitative analysis of the characteristics of ground behavior, this study measured 5 lateral lines. According to the result of the measurement, displacement happened little in the section to which countermeasure had been applied, but displacement of maximum 400mm happened in the section to which countermeasure had not bee applied. The analysis of data on displacement and rainfall suggested a close relationship between ground behavior and rainfall. According to the result of stability interpretation along with the change of ground saturation, stability rate appeared to be less than 1.0 when ground saturation is over 55%. Although the current trend of ground behavior is at a stable stage falling within the range of tolerance, it is considered necessary to continue monitoring and data analysis because ground displacement is highly possible with the change of temperature during the winter.