• Progress in Medical Physics
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• v.19 no.3
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• pp.178-185
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• 2008

Living donor liver transplantation is increasingly performed as an alternative to cadaveric transplantation. Preoperative screening of the donor candidates is very important. The quality, size, and vascular and biliary anatomy of the liver are best assessed with magnetic resonance (MR) imaging or computed tomography (CT). In particular, the volume of the potential graft must be measured to ensure sufficient liver function after surgery. Preoperative liver segmentation has proved useful for measuring the graft volume before living donor liver transplantations in previous studies. In these studies, the liver segments were manually delineated on each image section. The delineated areas were multiplied by the section thickness to obtain volumes and summed to obtain the total volume of the liver segments. This process is tedious and time consuming. To compensate for this problem, automatic segmentation techniques have been proposed with multiplanar CT images. These methods involve the use of sequences of thresholding, morphologic operations (ie, mathematic operations, such as image dilation, erosion, opening, and closing, that are based on shape), and 3D region growing methods. These techniques are complex but require a few computation times. We made a phantom for volume measurement with pig and evaluated actual volume of spleen and liver of phantom. The results represent that our semiautomatic volume measurement algorithm shows a good accuracy and repeatability with actual volume of phantom and possibility for clinical use to assist physician as a measuring tool.

• Journal of Korean Society of Steel Construction
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• v.28 no.6
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• pp.439-448
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• 2016

Extended end-plate connections(EEPC) are a type of connection applied in Pre-Engineered Building structures comprising beam-column connections of steel structures or tapered members. Extended end-plate connections(EEPC) show different behavioral characteristics owing to the influence of plate thickness, gauge distance of high strength bolt, diameter of high strength bolt frame, and the number of high strength bolts. In the USA and Europe, extended end-plate connections(EEPC) are applied in beam-column connections of steel structures in various forms; however, these are not widely applied in structures in Korea.This can be attributed to the fact that the proposal of design strength types for extended end-plate connections(EEPC), proposal of connection specifications, evaluation of seismic performance, and are not being performed appropriately. Therefore, the purpose of this study is to provide basic data for the domestic application of Unstiffened extended endplate connections. To realize this, nonlinear finite element analysis was conducted on a 12-mm thick Unstiffened extended endplate connections.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.636-643
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• 2008

The objective of this paper is to assess the potential use of the geogauge and the light falling weight deflectometer (LFWD) and the soil impact hammer as quality control/quality assurance $Q_C/Q_A$ devices for compacted soil layers. A comprehensive field experimental program considering variation of number of compaction, water contents and thickness of compaction layer was conducted on compacted layers of gravel sand. The geogauge, LFWD, the soil impact hammer and static load test (PLT) as a reference test were performed for the compacted layers. The geogauge elastic modulus, $E_G$, the LFWD dynamic modulus, ELFWD, empirical soil stiffness, $K_{30}$, obtained from soil impact hammer and soil stiffness directly obtained from PLT, $K_{30}$, were correlated with increasing number of compaction. The results of this study show that the geogauge, LFWD and the soil impact hammer, which are very simple to test, can be used as substituting devices for static PLT which is a conventional quality control/quality assurance $Q_C/Q_A$ devices for compacted soil layers.

• Journal of Periodontal and Implant Science
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• v.46 no.4
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• pp.220-233
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• 2016

Purpose: The aim of this study was to present new a model that allows the study of the bone healing process, with an emphasis on the biological behavior of different graft-to-host interfaces. A standardized "over-inlay" surgical technique combined with a differential histomorphometric analysis is presented in order to optimize the use of critical-size calvarial defects in pre-clinical testing. Methods: Critical-size defects were created into the parietal bone of 8 male Wistar rats. Deproteinized bovine bone (DBBM) blocks were inserted into the defects, so that part of the block was included within the calvarial thickness and part exceeded the calvarial height (an "over-inlay" graft). All animals were sacrificed at 1 or 3 months. Histomorphometric and immunohistochemical evaluation was carried out within distinct regions of interest (ROIs): the areas adjacent to the native bone (BA), the periosteal area (PA) and the central area (CA). Results: The animals healed without complications. Differential morphometry allowed the examination of the tissue composition within distinct regions: the BA presented consistent amounts of new bone formation (NB), which increased over time ($24.53%{\pm}1.26%$ at 1 month; $37.73%{\pm}0.39%$ at 3 months), thus suggesting that this area makes a substantial contribution toward NB. The PA was mainly composed of fibrous tissue ($71.16%{\pm}8.06%$ and $78.30%{\pm}2.67%$, respectively), while the CA showed high amounts of DBBM at both time points ($78.30%{\pm}2.67%$ and $74.68%{\pm}1.07%$, respectively), demonstrating a slow remodeling process. Blood vessels revealed a progressive migration from the interface with native bone toward the central area of the graft. Osterix-positive cells observed at 1 month within the PA suggested that the periosteum was a source of osteoprogenitor elements. Alkaline phosphatase data on matrix deposition confirmed this observation. Conclusions: The present model allowed for a standardized investigation of distinct graft-to-host interfaces both at vertically augmented and inlay-augmented sites, thus possibly limiting the number of animals required for pre-clinical investigations.

• Journal of Radiation Protection and Research
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• v.11 no.1
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• pp.57-64
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• 1986

This paper described an improved technical method required for proper evaluation of personnel exposures by means of the photographic dosimeter developed by KAERI in lower gamma or X-ray energy regions, with which response of the dosimeter varies significantly. With calibration of the dosimeter in the energy range from 30 to 300 keV, the beam spectrum was carefully selected and specified it adequately. The absorber combinations and absorber thickness used to obtain the specified X-ray spectra from a constant potential X-ray machine were determined theoretically and also experimentally. A correlation between the density and exposure for the four separate energies, such as $49\;keV_{eff},\;154\;keV_{eff}\;250\;keV_{eff}\;and\;662\;keV$, is experimentally determined. As a result, it can be directly evaluated the exposure from the measured response of dosimeter.

• Culinary science and hospitality research
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• v.22 no.7
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• pp.173-186
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• 2016

This study was conducted to investigate quality characteristics of white pan bread with Cudrania tricuspidata leaf powder having functional components. Mixograph, pH, TPA, volume, specific volume, moisture, CrumbScan, color value, sensory evaluation and shelf-life test were performed on the white pan bread with Cudrania tricuspidata leaf powder. The obtained results are as follows. Mixogram analysis results showed that the dough with Cudrania tricuspidata leaf powder was suitable for baking quality. The more Cudrania tricuspidata leaf powder was added in the dough, the higher dough pH was and the lower pH values after fermentation and of the final productwere. TPA analysis results showed that higher amounts of Cudrania tricuspidata leaf powder resulted in increased hardness, chewiness, and gumminess of the white pan bread. Volume and specific volume of white pan bread were decreased with increased amounts of Cudrania tricuspidata leaf powder. CrumbScan images showed that fineness of grain, crust thickness, and volume of the bread were significantly different depending on the amount of Cudrania tricuspidata leaf powder. While color value analysis showed that increasing the amount of Cudrania tricuspidata leaf powder resulted in low L and a values. The results of the acceptance test showed that CLP3 had better scores in the appearance and texture characteristics than the control, while taste and overall acceptance were higher in the CLP2 compared with the control. According to the results of the shelf-life test, the white pan bread with 1~2% of Cudrania tricuspidata leaf powder had a significantly lower hardness when compared with the control. It was judged that a lower amount of Cudrania tricuspidata leaf powder could help in maintaining the softness of bread crumbs. Moisture content in the white pan bread decreased with the increased amounts of Cudrania tricuspidata leaf powder, but there were no significant differences among specimens.

• Journal of the Korea Concrete Institute
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• v.16 no.2 s.80
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• pp.139-146
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• 2004

Recently, interest on the performance of the construction temporary equipment have been greatly increased. Since the application of the 'Performance Test Code' for the equipment in 1992 according to the Industrial Safety and Health Act, a basic study of Steel Pipe Supports have been carried out for the last 2 years based on the Performance Test Results. The present code specification for the Steel Pipe Supports and research status are introduced. So far, total 849 specimen have been examined on their outer and inner pipe's length, thickness, their overlapping length, and their load carrying capacities. The test was conducted separately into two groups - used and new equipment, and it was found that the used ones revealed a decrease on their load carrying capacity, almost $10\%$ compared to the new ones. Considering this fact, it is strongly recommended to ensure the quality of the equipment before use at the jobsite. First of all, based on this basic investigation, the statistical values on the Steel Pipe Supports are suggested and further analysis on the effect of each component is in progress. It is, however, expected that this report can be used as a basic information on the Steel Pipe Supports.

• Journal of the Korea Concrete Institute
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• v.27 no.1
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• pp.21-28
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• 2015

Recent studies on concrete floating structure development focused on connection system of concrete modules. Precast concrete modules are designed to be attached by prestressing in the water, exposing the structure to the loads from water and making the construction difficult. Therefore, a development of bond material became a key issue in successful connection of floating concrete modules. In this study, micro-silica mixed aqua epoxy (MSAE) is developed for the task. Existing primer aqua epoxy, originally used as a bond material for the retrofit of concrete structures using fiber reinforced polymers, is evaluated to find the optimum micro-silica added mix proportion. Micro-silica of 0~4 volume % was mixed in standard mixture of aqua epoxy. Then, the material property tests were performed to study the effect of micro-silica in aqua epoxy by controlling the epoxy silane proportion by 0, ${\pm}5$, ${\pm}10%$. The optimum mix design of MSAE was derived based on the test results. The MSAE was used to connect concrete module specimens with the epoxy thickness variation of 5, 10, and 20mm. Then, 3-point loading test was performed to verify the bond capacity of MSAE. The results show that MSAE improves the bond capacity of concrete module.

• Journal of the Korea Concrete Institute
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• v.20 no.3
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• pp.393-404
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• 2008

The approaches in many design codes for the estimation of the deflection of flexural reinforced concrete (RC) members utilize the concept of the effective moment of inertia which considers the reduction of flexural rigidity of RC beams after cracking. However, the effective moment of inertia in design codes are primarily based on the ratio of maximum moment and cracking moment of beam subjected to loading without proper consideration on many other possible influencing factors such as span length, member end condition, sectional size, loading geometry, materials, sectional properties, amount of cracks and its distribution, and etc. In this study, therefore, an experimental investigation was conducted to provide fundamental test data on the effective moment of inertia of RC beams for the evaluation of flexural deflection, and to develop a modified method on the estimation of the effective moment of inertia based on test results. 14 specimens were fabricated with the primary test parameters of concrete strength, cover thickness, reinforcement ratio, and bar diameters, and the effective moments of inertia obtained from the test results were compared with those by design codes, existing equations, and the modified equation proposed in this study. The proposed method considered the effect of the length of cracking region, reinforcement ratio, and the effective concrete area per bar on the effective moment of inertia, which estimated the effective moment of inertia more close to the test results compared to other approaches.

• Journal of Periodontal and Implant Science
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• v.33 no.2
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• pp.289-299
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• 2003

The autogenous free gingival graft is the most predictable procedure currently used to increase the width of　the attached gingiva in periodontics. But the major disadvantage of the procedure is to create the multiple surgical wounds at both a donor site and a recipient site. The other problem is the limited amount of available　graft material in oral cavity. Therefore, recent researches have been focused to develop the biomaterial to substitute the autogenous gingival tissue. The purpose of this study was to evaluate the histologic healing after　grafting of bilayer artificial dermis, compared to the free gingival graft. Four non-smoking subjects (mean age, 32.5 years) in systemically healthy state and good oral hygiene were selected according to their particular needs for correction of mucogingival problems as suggested by Nabers(1966). The recipient sites were prepared through the procedure for the free gingival graft and were grouped according to the graft materials: Experimental group(n=5) - bilayer artifcia1 dermis ($Terudermis^{(R)}$; Terumo Co. Japan) and Control group(n=6) - free gingival graft with autogenous palatal mucosa. Biopsies were harvested at 1,2,3 and 6 weeks postsurgery to evaluate histologically. At the third week in the experimental group and at the second week of in the control group, the grafts has been clinically stabilized on the recipient bed and the graft border has been blended into the surrounding tissue. In the experimental group after 1 week of grafting, the epithelial migration from the adjacent tissue to graft material was seen and after 3 weeks of grafting, the : nflmmation decreased, collagen layer of the artificial dermis was lost and the basement membrane of epithelium was formed. After 6 weeks of grafting, both groups demonstrated orthokeratinized epithelium and increased thickness of epithelial tissue and the rete peg formation, similar to the adjacent tissue, Histologic evaluation revealed a biologic acceptance and incorporation of the collagen layers of the graft tissue to the host tissue, without foreign body reaction. In conclusion, a bilayer artificial dermis is essentially similar to autogeneous free gingival graft in the correction of mucogingival problems, and has the advantages of decreased patient morbidity (no donor site) and availability of abundant amounts of graft material when needed.