• Journal of the Korean Society of Radiology
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• v.7 no.5
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• pp.313-320
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• 2013

For some patients with joint illnesses such as rheumarthritis or varus deformity, the total knee arthroplasty (TKA) procedures are performed. However, when inserting metal cutting guide for the procedures, due to the femoral shaft bowing, complications such as the cortex of the femoral shaft damages or secondary fractures can be caused. If the central coordinate value of the femoral shaft is known, the metal cutting guide could be inserted into the anatomical center, so such complications can be prevented. In this study, CT images of femoral shafts of 10 individuals in the experiment group who are in need of receiving the total knee arthroplasty procedures and those of 10 individuals in the control group without illness in the femoral shaft have been utilized to locate the 3-dimensional coordinate values. Then, Matlab was utilized to identify the central coordinate value in order to obtain a graph reflecting the anatomical shapes as well as to acquire the 3-dimensional radial curvature values by section. As a result, the average curvature range and standard deviation of femoral shafts of the experiment group was determined to be $758.15{\pm}206.3mm$ whereas the that of the control group was determined to be $1672.97{\pm}395.6mm$. The statistical significance of the measured results was verified through f-distribution analysis. Based on these results, it was verified that the level of curvature of the femoral shaft of the experiment group was higher. If the anatomical central points are located and analyzed using this methodology, it would be helpful in performing orthopedic operations such as the total knee arthroplasty.

• The Journal of Engineering Geology
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• v.25 no.1
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• pp.115-129
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• 2015

The cut-slope of a large-sectional tunnel portal is recognized as a potential area of weakness due to unstable stress distribution and possible permanent displacement. This paper presents a case study of a slope failure and remediation for a large-scale cut-slope at a tunnel portal. Extensive rock-slope brittle failure occurred along discontinuities in the rock mass after 46 mm of rainfall, which caused instability of the upper part of the cut-slope. Based on a geological survey and face mapping, the reason for failure is believed to be the presence of thin clay fill in discontinuities in the weathered rock mass and consequent saturationinduced joint weakening. The granite-gneiss rock mass has a high content of alkali-feldspar, indicating a vulnerability to weathering. Immediately before the slope failure, a sharp increase in displacement rate was indicated by settlement-time histories, and this observation can contribute to the safety management criteria for slope stability. In this case study, emergency remediation was performed to prevent further hazard and to facilitate reconstruction, and counterweight fill and concrete filling of voids were successfully applied. For ultimate remediation, the grid anchor-blocks were used for slope stabilization, and additional rock bolts and grouting were applied inside the tunnel. Limit-equilibrium slope stability analysis and analyses of strereographic projections confirmed the instability of the original slope and the effectiveness of reinforcing methods. After the application of reinforcing measures, instrumental monitoring indicated that the slope and the tunnel remained stable. This case study is expected to serve as a valuable reference for similar engineering cases of large-sectional slope stability.

• Journal of the Korean Society of Food Culture
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• v.27 no.4
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• pp.407-413
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• 2012

In previous studies, we performed joint animal studies and clinical trials between Yonsei University and Oryza Oil & Fat Chemical Co. Ltd. We have shown that coffee bean extract has potent anti-obesity and hypotriglyceridemic activities as well as beneficial effects on body fat reduction.In this study, the effects of coffee bean extract (100 mg/capsule) on body fat reduction were evaluated in overweight/obese women (body mass index of 25~30 $kg/m^2$ or body fat > 30%) not diagnosed with any type of disease. Subjects were randomly assigned to a coffee bean extract group (n=10) or placebo group (n=10). We measured anthropometric parameters, abdominal fat distribution by computed tomography and blood components before and after the 8week intervention period. After supplementation, the coffee bean extract group showed body weight (p=0.08), body mass index (p=0.06), hip circumference (p<0.05), and upper waist circumference (p< 0.01). In addition, after 8 weeks, the coffee bean extract group showed a significant decrease in abdominal internal fat area compared to 0 weeks (0 weeks : $155.8cm^2$; 8 weeks : $145.9cm^2$, ${\Delta}$ change : $-9.9cm^2$, respectively). However, there were no significant differences in lipid profiles or serological measurements between the coffee bean extract group and placebo group. The results of our human study demonstrated that coffee bean extract supplementation for 8 weeks has beneficial effects on reducing abdominal internal fat area as well as hip and waist circumferences.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.1
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• pp.15-23
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• 1995

In order to investigate the relation between the phytoplankton and the catch fluctuation of set net fishing grounds located in the coastal waters of Yeosu, phytoplankton observations on the fishing ground were carried out by the training ship of Yeosu, Fisheries University from April to November in 1990, and the data obtained were compared with the catch data from the joint market of yeosu fisheries cooperative society in 1990. The results obtained are summarized as follows: 1) The phytoplanktons were more appeared in summer than in spring or autumn and their quantity was much in the shore of Dolsan-do, and little in the offshore waters distributed in the shores of Sori-do and Sejon-do, Thus, the quantity of the planktons could be used for estimating the distribution of watermass. 2) The fishes caught by the set net were arranged in the order of catch amounts as follows: Spanish mackerel > Hair tail > Common mackerel > Sardine > Anchovy > Horse mackerel > Yellow tail. The catches of anchovy and Sardine were high in April to May and Hair tail. Horse mackerel and Common mackerel were caught from June to October. But Spanish mackerel were caught during the whole period of fishing. 3) The catches by set nets showed a correlation with the quantity of phytoplanktons. The planktons appeared most in the inner waters. influenced largely by the inflow of land waters in summer. and the catches were high in summer when the offshore water was distributed least. Therefore, the most important factor influencing the catches were regarded to be the productivity of food organism in inner water into which abundant nutrients were supplied by the inflow of land waters. That is, the fluctuation of catches by set nets seemed to be influenced mainly by the productivity of food organism.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.5
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• pp.1334-1343
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• 2008

Growing needs for efficient management of water resources urge the joint operation of dams and integrated management of whole basin. As one of the tools for supporting above tasks, this study aims to constitute a hydrologic model that can simulate the streamflow discharges at some control points located both upper and down stream of dams. One of the currently available models is being studied to be applied with a least effort in order to support the ongoing project of KWATER (Korea Water Resources Corporation), "Establishment of integrated operation scheme for the dams in Han River Basin". On this study, following works have been carried out : division of Han River Basin into 24 sub-basins, use of rainfall data of 151 stations to make spatial distribution of rainfall, selection of control points such as Soyanggang Dam, Chungju Dam, Chungju Release Control Dam, Heongseong Dam, Hwachun Dam, Chuncheon Dam, Uiam Dam, Cheongpyung Dam and Paldang Dam, selection of SSARR (Streamflow Synthesis and Reservoir Regulation) model as a hydrologic model, preparation of input data of SSARR model, sensitivity analysis of parameter using hydrologic data of 2002. The sensitivity analysis showed that soil moisture index versus runoff percent (SMI-ROP), baseflow infiltration index versus baseflow percent (BII-BFP) and surface-subsurface separation (S-SS) parameters are higher sensitive parameters to the simulation result.

• Journal of Korean Tunnelling and Underground Space Association
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• v.6 no.4
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• pp.327-343
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• 2004

During tunnel construction, ground failures often occur due to existence of weak zones, such as faults, joints, and cavities, ahead of tunnel face. It is hard to detect effectively weak zones, which can lead underground structure to fail after excavation and before supporting, by using conventional characterization methods. In this study, an enhanced analytical method of predicting weak zones ahead of tunnel face is developed to overcome some problems in the conventional geophysical exploration methods. The analytical method is based on Coulomb's and Gauss' laws with considering the characteristics of electric fields subjected to rock mass. Using the developed method, closed form solutions are obtained to detect a spherical shaped zone and an oriented fault ahead of tunnel face respectively. The analytical results suggest that the presence of weak zones and their sizes, location, and states can be accurately predicted by combining a proper inversion process with resistance measured from several electrodes on the tunnel face. It appears that the skin depth or resistivity in rock mass is affected by the diameter of tunnel face, natural electric potential and noises induced by experimental measurement and spatial distribution of uncertain properties. The developed analytical solution is verified through experimental tests. About 1800 concrete blocks of 5cm by 5cm by 5cm in size are prepared and used to model a joint rock mass around tunnel face. Weak zones are simulated ahead of tunnel face with a material which has relatively higher conductivity than concrete blocks. Experimental results on the model test show a good agreement with analytical results.

• Journal of Biomedical Engineering Research
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• v.31 no.3
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• pp.199-209
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• 2010

The locking compression plates-distal femur(LCP-DF) are being widely used for surgical management of the extra-articular complex fractures of the distal femur. They feature locking mechanism between the screws and the screw holes of the plate to provide stronger fixation force with less number of screws than conventional compression bone plate. However, their biomechanical efficacies are not fully understood, especially regarding the number of the screws inserted and their optimal configurations. In this study, we investigated effects of various screw configurations in the shaft and the condylar regions of the femur in relation to structural stability of LCP-DF system. For this purpose, a baseline 3-D finite element (FE) model of the femur was constructed from CT-scan images of a normal healthy male and was validated. The extra-articular complex fracture of the distal femur was made with a 4-cm defect. Surgical reduction with LCP-DF and bone screws were added laterally. To simulate various cases of post-op screw configurations, screws were inserted in the shaft (3~5 screws) and the condylar (4~6 screws) regions. Particular attention was paid at the shaft region where screws were inserted either in clustered or evenly-spaced fashion. Tied-contact conditions were assigned at the bone screws-plate whereas general contact condition was assumed at the interfaces between LCP-DF and bone screws. Axial compressive load of 1,610N(2.3 BW) was applied on the femoral head to reflect joint reaction force. An average of 5% increase in stiffness was found with increase in screw numbers (from 4 to 6) in the condylar region, as compared to negligible increase (less than 1%) at the shaft regardless of the number of screws inserted or its distribution, whether clustered or evenly-spaced. At the condylar region, screw insertion at the holes near the fracture interface and posterior locations contributed greater increase in stiffness (9~13%) than any other locations. Our results suggested that the screw insertion at the condylar region can be more effective than at the shaft during surgical treatment of fracture of the distal femur with LCP-DF. In addition, screw insertion at the holes close to the fracture interface should be accompanied to ensure better fracture healing.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.103-115
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• 2011

Concrete slab curls and warps due to the uneven distribution of temperature and moisture and as the result, internal stress develops within the slab. Therefore, environmental loads must be considered in addition to the traffic loads to predict the lifespan of the concrete pavement more accurately. The strength of the concrete slab is gradually decreases to a certain level at which fatigue cracking is generated by the repetitive traffic and environmental loadings. In this study, a new fatigue regression model was developed based on the results from previously performed studies. To verify the model, another laboratory flexural fatigue test program which was not used in the model development, was conducted and compared with the predictions of other existing models. Each fatigue model was applied to analysis logic of cumulative fatigue damage of concrete pavement developed in the study. The sensitivity of cumulative fatigue damage calculated by each model was analyzed for the design factors such as slab thickness, joint spacing, complex modulus of subgrade reaction and the load transfer at joints. As the result, the model developed in this study could reflect environmental loading more reasonably by improving other existing models which consider R, minimum/maximum stress ratio.

• The Journal of the Acoustical Society of Korea
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• v.34 no.6
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• pp.423-431
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• 2015

KIOST-HYU joint acoustics experiment was performed on the western shallow water off the Taean peninsula in the Yellow Sea in May 2013. In this paper, mid-frequency (6~16 kHz) bottom loss data measured in a grazing angle range of $17{\sim}60^{\circ}$ are presented and compared to the predictions obtained using a Rayleigh reflection model. The sediment structure of the experimental site was characterized by multi-layered sediment and the components of the surficial sediment consisted of various types of particles with a mean grain size of $5.9{\phi}$. The model predictions obtained using the mean grain size were not in agreement with the measured bottom loss, and those obtained using the grain size of $4{\phi}$, which was estimated by an inversion process, showed a best fit to the measurements. It would be because the standard deviation of the gain-size distribution of surficial sediment is $4.3{\phi}$, which is much larger than those of other areas around the experimental site. Finally, the model predictions obtained using the geoacoustic parameters estimated from the inversion process for the surficial sediment layer and those corresponding to the mean grain size of $1.3{\phi}$ for lower layer are reasonably agreement with the measured bottom loss data.

• Journal of agricultural medicine and community health
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• v.21 no.2
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• pp.231-241
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• 1996

The estimation of medical care status and the planning of health service program should be done according to each community resident's socio-medical background and public health service. In this point, it is most necessary to be set the exact and new socio-economic statistics data in Nepal, one of the worst countries in national health status. We surveyed 668 house, 3,425 residents in Dolka area, Nepal from January 25th to February 1st, 1995. 1. In personal characteristics, the ratio of men and women was similar, the person who were below 19 years old were 28.1% and the single were 52.4%. The illeterate person were 50.3% and the lower group in economic status which had been estimated by interviewers were 46.9%. 2. In sanitational characteristics, the person who used stream water or rainwater to drink were 42.2% and the person who always boiled water to drink were only 8.3%. The person who had not toilet in their house were 67.3% and the lower group in sanitational status which had been estimated by interviewers were 61.8%. 3. The prevalence rate of illness during the last one month were 8.6% and the chronic were 26.1% and the acute were 72.5%. The distribution of sickness symptom were headache, fever and joint pain in order and the person who took no medical treatment among the sick were 37.0%. The patterns of medical utilization were public health center, hospital and pharmacy in order. 4. Illness prevalence was significantly related to sex, age, merital status and educational experience. The residents who were women, 40 years old or more, married and had not educational experience were apt to take illness. 5. Medical utilization was significantly related to educational experience, job, distance from home to medical facilities and economic status. The person who had educational experience, were officer workers or merchants, lived near by medical facilities and had higher economic status took medical treatment very well.