• Tunnel and Underground Space
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• v.13 no.5
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• pp.331-343
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• 2003

Though the Grouting has been in use for a long time, it is still regarded as an technique rather than engineering. The study of ground improvement by grouting is rare especially in jointed rock mass. In this study, biaxial compression tests were performed in the jointed rock mass models with .ough surfBce joints assembled with blocks before and after grouting. The load-deformation curves of the jointed rock masses showed a non-linear relationship before grouting but showed a relatively linear deformaion behavior after grouting. Improvement ratio (deformation modulus after grouting/deformation modulus before grouting) decreased with increasing joint spacing and lateral stress. Improvement ratio decreased exponentially with increasing deformation modulus of the rock mass model before grouting. Three-dimensional FDM analysis was performed to a highway tunnel case using experimental data of grouted rock. The convergence of the tunnel predicted after grouting by the numerical modelling coincided with those attained from the field measurement.

• Journal of Korea Technology Innovation Society
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• v.19 no.1
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• pp.105-136
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• 2016

This paper analyzed the qualitative evaluation indicators of the SYSTEM sector of the LINC program, which aimed at strengthening ability of regional universities through the activities of industry-academia cooperation (IAC). By using interview data and the program reports of universities, this research explored the problems of the indicators and suggested improvement measures which could lead to performance creativity. According to research results, in university system reform for activating IAC, some improvements are required as follows: limiting excessive expansion of IAC-friendly faculty evaluation; and evaluating soft aspects in the reform of academic affairs. In relation to strengthening of ability of the IAC organization, the indicators need to be amended as follows: enhancing the role of channel of IAC Foundation; strengthening the function of planning team of the IAC Foundation; and inducing development of own model of universities for IAC. As regards expansion of IAC infrastructure, it is necessary to enlarge the manpower who can develop programs of the support center in the foundation and to secure of operators for effective operation of joint-using equipments. Therefore, the indicators are required to be upgraded, considering these improvement direction.

• Magazine of the Korea Concrete Institute
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• v.11 no.2
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• pp.147-156
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• 1999

An investigation was conducted into the flexural behavior of earthquake damaged reinforced concrete columns repaired with carbon fiber sheets. Six column specimens were tested to failure under reversed cyclic loading. Two columns were specimens for control with no sheets and tested. These columns were repaired with carbon fiber sheets and retested to evaluate the effect of the confinement of the carbon fiber on the damaged column. Another two columns were repaired and tested with no pre-cyclic loading. The test specimens were designed to model single bent under a constant axial force with reversed cyclic lateral loading. Carbon fiber sheets were used to repair damaged concrete columns in the critically stressed areas near the column footing joint and the physical, mechanical properties of carbon fiber sheets are described. The performance of repaired columns in terms of their hysteretic response is evaluated and compared to those of the original columns. The results indicate that the repaire technique with carbon fiber sheets is highly effective. Both flexural strength and displacement ductility of repaired columns were higher than those of the original columns.

• IMMUNE NETWORK
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• v.14 no.1
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• pp.45-53
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• 2014

Osteoarthritis (OA) is a degenerative joint disease characterized by a progressive loss of cartilage. And, increased oxidative stress plays a relevant role in the pathogenesis of OA. Ursodeoxycholic acid (UDCA) is a used drug for liver diseases known for its free radical-scavenging property. The objectives of this study were to investigate the in vivo effects of UDCA on pain severity and cartilage degeneration using an experimental OA model and to explore its mode of actions. OA was induced in rats by intra-articular injection of monosodium iodoacetate (MIA) to the knee. Oral administration UDCA was initiated on the day of MIA injection. Limb nociception was assessed by measuring the paw withdrawal latency and threshold. Samples were analyzed macroscopically and histologically. Immunohistochemistry was used to investigate the expression of interleukin-$1{\beta}$ (IL-$1{\beta}$), IL-6, nitrotyrosine and inducible nitric oxide synthase (iNOS) in knee joints. UDCA showed an antinociceptive property and attenuated cartilage degeneration. OA rats given oral UDCA significantly exhibited a decreased number of osteoclasts in subchondral bone legion compared with the vehicle-treated OA group. UDCA reduced the expression of IL-$1{\beta}$, IL-6, nitrotyrosine and iNOS in articular cartilage. UDCA treatment significantly attenuated the mRNA expression of matrix metalloproteinase-3 (MMP-3), -13, and ADAMTS5 in IL-$1{\beta}$-stimulated human OA chondrocytes. These results show the inhibitory effects of UDCA on pain production and cartilage degeneration in experimentally induced OA. The chondroprotective properties of UDCA were achieved by suppressing oxidative damage and inhibiting catabolic factors that are implicated in the pathogenesis of cartilage damage in OA.

• Journal of the Korean Data and Information Science Society
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• v.27 no.2
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• pp.363-372
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• 2016

Two-stage sample designs are commonly used for household surveys in Korea using as clusters the enumeration districts (EDs). Since clustering decomposes the population variation into within- and between-cluster variations, the sample sizes allocated in stages can affect the overall precision. Alternative clusters are often considered due to diverse reasons such as the EDs' limitation in size, being out-of-date, and in-assessibility to their household lists. In addition, the EDs are currently under development by the Statistics Korea as an joint effort toward their transition from the traditional practice to the register census from 2015. We present an approach for evaluating the difference in the precision of the mean estimators of the sets of the cluster units in between a hierachical and nested form, where the design effect is used to reflect the effect of the clustering and the sample allocation. We also demonstrate our approach using the U.S. Census counts from the year 2000 for Anne Arundel County in Maryland. Our research shows that the within-cluster variance can be significantly different for survey variables and thus the choice of cluster units and the associated sample allocation scheme should reflect the corresponding variance decomposition due to clustering.

• Journal of the Korean Society for Library and Information Science
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• v.47 no.2
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• pp.25-43
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• 2013

South Korea has fewer public libraries than other developed nations of OECD. This calls for a more diverse role of school libraries in the geographically isolated areas. School libraries should provides services for not only its students and faculty, but also the surrounding neighborhood as a part of cultural community. Based on the needs for an expanded role of school libraries, this research aims to identify the necessary factors for school libraries to provide services to their local residents. Two things should be identified for this research. First, we should confirm the necessity of policies that provide library services to local residents of school libraries. Second, we should propose a way to have the libraries as a part of cultural community where meet the information and cultural demand of their local residents. The study surveyed users, school principals and working-level staff members of cultural communities in order to study the two questions. These groups were from Uri-school Village Library, which is supported by the NHN Culture Foundation. Through the survey, the research confirmed the need for a consistent outside assistance, job training, open door policy for local residents and diverse library services in order for school libraries to serve their local community.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.6
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• pp.498-507
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• 2017

Electronic equipments comprised of high density components with various packaging types have been recently applied to a satellite. Therefore, to guarantee high reliability of electrical equipment, a design approach, which can reduce the development period and cost through an early diagnosis in potential risks of failure, should be established. In the previous research, the reliability assesment of the electronic equipments have based on Steinberg's fatigue failure theory. However, this theory was not enough for further investigation of life prediction and reliability of the electronic equipments comprised of various sizes and packaging types due to its theoretical limitations and analysis results sensitivity with regard to different modeling technic. In that case, if detailed finite element model is established, aforementioned problems can be readily solved. However, this approach might arise disadvantage of spending much time. In this paper, to establish strategy for high reliability design of electronic equipment, we performed mechanical reliability evaluation of CCB (Camera Controller Box) at qualification level based on the approach using Sherlock unlike design techniques applied to existing business.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.4
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• pp.871-877
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• 2008

Heme oxygenase-1 (HO-1), an inducible heme-degrading enzyme, is expressed by macrophages and endothelial cells in response to various stresses and mediators of inflammation. HO-1 has been recently implicated in regulation of angiogenesis via expression of VEGF. The purpose of this study was to determine the effects of HO-1 modulation on the collagen-induced arthritis (CIA) model and on angiogenesis via up- regulation of VEGF expression in human synovial fibroblast. DBA/1J mice were treated with an inhibitor of HO-1, tin protoporphyrin IX (SnPP), or with an inducer of HO-1, cobalt protoporphyrin IX (CoPP), from day 1 to day 35 after CIA induction. The clinical evolution of disease was monitored visually. At the end of the experiment, histopathologic changes were examined on the joints. VEGF expression in paws were measured by immunohistochemical stain. mRNA expression of HO-1 and VEGF stimulated with various concentration of $TNF-{\alpha}$, CoPP accessed on human synovial fibroblast by RT-PCR. Effects of pretreatment with SnPP on mRNA expression of HO-1 and VEGF in the presence of CoPP and $TNF-{\alpha}$ in synovial fibroblast was accessed by Real-time RT-PCR. Administration of cobalt protoporphyrin IX significantly induced the inflammatory response, with increased arthritis index and expression of VEGF in the paws of the arthritis models. Treatment with SnPP significantly reduced the severity of CIA through inhibition of joint inflammation and cartilage destruction. The expression of VEGF were also significantly reduced by SnPP treatment in the paw. CoPPIX as inducer of HO-1, increased HO-1 and VEGF expression dose dependently in synovial fibroblast. In contrast, inhibition of HO-1 activity by SnPPIX abrogated CoPPIX-induced HO-1 and VEGF production in synovial fibroblast. Stimulation with $TNF-{\alpha}$ increased HO-1 and VEGF expression itself and showed additive effect on HO-1 and VEGF expression when it treated with CoPP. When SnPP was treated with CoPP and $TNF-{\alpha}$, it abrogated the CoPP induced HO-1 and VEGF expression and also abrogated $TNF-{\alpha}$ induced HO-1 and VEGF expression in synovial fibroblast. The effects of HO-1 induction in rheumatoid arthritis results in aggravation of arthritis via up-regulation of VEGF. I concluded that inhibition of the expression or activity of HO-1 could be a therapeutic target of rheumatoid arthritis.

• Journal of Korea Water Resources Association
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• v.40 no.4
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• pp.335-343
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• 2007

Drought characteristics need to be preceded before establishing a drought mitigation plan. In this study, using a Standardized Precipitation Index (SPI), a hydrologic drought was defined as an event during which the SPIs are continuously below a certain truncation level. Then, a methodology of drought frequency analysis was performed to quantitatively characterize droughts considering drought duration and severity simultaneously. The theory of runs was used to model drought recurrence and to determine drought properties like duration and severity. Short historical records usually do not allow reliable bivariate analyses. However, more than hundred years of precipitation data (1770 ${\sim}$ 1907) collected in Chosun Kingdom Age using an old Korean rain gage called Chukwooki can provide valuable information about past events. It is shown that a bivariate gamma distribution well represented the joint probabilistic properties of Korean drought duration and severity. The overall results of this study show that the proposed bivariate drought frequency analysis overcomes the drawbacks of the conventional univariate frequency analysis by providing a consistent representation of the drought recurrent property.

• Journal of the Korean Geotechnical Society
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• v.27 no.2
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• pp.91-101
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• 2011

In this study, a new design method of Pile-Bent structure considering plastic hinge was proposed on the basis of the beam-column model. To obtain the detailed informations, the optimized cross-section ratio between column and pile was analyzed to induce the plastic hinge at the joint section between the pile and column. Base on this study, the optimized diameter ratio of pile and column can be obtained below the inflection point of the bi-linear curve depending on the relations between column-pile diameter ratio ($D_c/D_p$) and normalized lateral cracking load ratio ($F/F_{Dc=Dp}$). Moreover, through comparisons with field cases to find out in-depth limit in which minimum concrete-steel ratio could be applied, in-depth limits ($L_{As=0.4%}$) normalized by the pile length ($L_p$) proportionally decrease as the pile length ($L_p/D_p$)increases up to $L_p/D_p=17.5$, and beyond that in-depth limit converges to a constant value (${\simeq}0.3$).