• Journal of Astronomy and Space Sciences
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• v.26 no.3
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• pp.305-316
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• 2009

In this study, we suggest an empirical forecast of CIR (Corotating Interaction Regions) and geomagnetic storm based on the information of coronal holes (CH). For this we used CH data obtained from He I $10830{\AA}$ maps at National Solar Observatory-Kitt Peak from January 1996 to November 2003 and the CIR and storm data that Choi et al. (2009) identified. Considering the relationship among coronal holes, CIRs, and geomagnetic storms (Choi et al. 2009), we propose the criteria for geoeffective coronal holes; the center of CH is located between $N40^{\circ}$ and $S40^{\circ}$ and between $E40^{\circ}$ and $W20^{\circ}$, and its area in percentage of solar hemispheric area is larger than the following areas: (1) case 1: 0.36%, (2) case 2: 0.66%, (3) case 3: 0.36% for 1996-2000, and 0.66% for 2001-2003. Then we present contingency tables between prediction and observation for three cases and their dependence on solar cycle phase. From the contingency tables, we determined several statistical parameters for forecast evaluation such as PODy (the probability of detection yes), FAR (the false alarm ratio), Bias (the ratio of "yes" predictions to "yes" observations) and CSI (critical success index). Considering the importance of PODy and CSI, we found that the best criterion is case 3; CH-CIR: PODy=0.77, FAR=0.66, Bias=2.28, CSI=0.30. CH-storm: PODy=0.81, FAR=0.84, Bias=5.00, CSI=0.16. It is also found that the parameters after the solar maximum are much better than those before the solar maximum. Our results show that the forecasting of CIR based on coronal hole information is meaningful but the forecast of goemagnetic storm is challenging.

• Journal of Digital Convergence
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• v.10 no.10
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• pp.215-220
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• 2012

This paper proposes a ontology of tree structure approach for adaptive object recognition in a situation-variant environment. In this paper, we introduce a new concept, ontology of tree structure ontology, for context sensitivity, as we found that many developed systems work in a context-invariant environment. Due to the effects of illumination on a supreme obstinate designing context-sensitive recognition system, we have focused on designing such a context-variant system using ontology of tree structure. Ontology can be defined as an explicit specification of conceptualization of a domain typically captured in an abstract model of how people think about things in the domain. People produce ontologies to understand and explain underlying principles and environmental factors. In this research, we have proposed context ontology, context modeling, context adaptation, and context categorization to design ontology of tree structure based on illumination criteria. After selecting the proper light-ontology domain, we benefit from selecting a set of actions that produces better performance on that domain. We have carried out extensive experiments on these concepts in the area of object recognition in a dynamic changing environment, and we have achieved enormous success, which will enable us to proceed on our basic concepts.

• Journal of Technologic Dentistry
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• v.31 no.1
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• pp.23-36
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• 2009

The goal of esthetic restoration is to achieve morphologic, optical, and biologic acceptance. Creation of a natural looking ceramic restoration, which blends harmoniously with surrounding dentition, is not always achieved. A successful color match is an important aspect of any esthetic dental restoration. Since natural enamel has inherent translucency, it is important that ceramic restorations reproduce the translucency and color of the natural teeth. However, the final color match of porcelain crowns to adjacent natural dentition remains some problem. Difficulties related to color matching arise from the structural differences that exist between metal ceramic crowns and natural teeth, the limited range of available ceramic shades, inadequate shade guides, different types of metal alloys, repeated firing, the condensation technique, and varying compositions of ceramic materials. Many factors contribute to the esthetic success of dental restoration: optical properties such as color and its elements of hue, value, and chroma; translucency and opacity; light transmission and scattering; and metamerism and fluorescence. The purpose of this study was to determine the color changes of metal-ceramic system with different veneering porcelain powder after repeated firing. The objectives of this in vitro study were to measure the lightness($L^*$), chromaticity($a^*$), chromaticity($b^*$), chroma($C^*$), hue(h), reflectance(%), color difference(${\Delta}E$). The following conclusions were obtained: 1. An increase in the number of firings resulted in decrease in lightness($L^*$) but increase in chromacticity($a^*$) with all porcelain. After the second sintering resulted in decrease in chromacticity($b^*$) with opaque-dentin porcelain and dentin porcelain but in increase with enamel porcelain and translucency porcelain. And after the second sintering resulted in decrease in chroma($C^*$) with opaque-dentin porcelain and dentin porcelain, but on the whole side in decrease with enamel porcelain and translucency porcelain. 2. After the second firing, a increase in the number of firings resulted in decrease reflectance(%) in all wavelength. 3. There were noticeable color differences(${\Delta}E$) between first sintering and multiple firings(dentin porcelain: 5.29~8.15, opaque-dentin porcelain: 4.83~8.2, enamel porcelain: 8.93~13.15, translucency porcelain: 9.37~12.91), but the color difference(${\Delta}E$) after second sintering were down to 4.87 in all porcelain. 4. Given the NBS Criteria, a 'trace' was not found this study but a 'slight' was found 2-3, 3-5 in dentin porcelain, 2-3 in opaque-dentin porcelain, 3-5, 5-10 in enamel porcelain and translucency porcelain, a 'noticeable' was 2-5, 3-10, 5-10 in dentin porcelain and opaque-dentin porcelain, 2-3, 2-5, 3-10 in enamel porcelain 2-3, 3-10 in translucency porcelain, an 'appreciable' was 1-2, 1-3, 2-10 in dentin porcelain 1-2, 1-3, 2-10, 3-10 in opaque-dentin porcelain, 2-10 in enamel porcelain, 2-5, 2-10 in translucency porcelain, a 'much' was 1-5, 1-10 in dentin porcelain and opaque-dentin porcelain, 1-2, 1-3, 1-5 in enamel porcelain 1-2, 1-3, 1-5, 1-10 in translucency porcelain, a 'very much' was 1-10 in enamel porcelain.

• The KIPS Transactions:PartC
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• v.17C no.3
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• pp.271-280
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• 2010

For the next generation mobile communication system, diverse wireless network techniques such as beyond 3G LTE, WiMAX/WiBro, and next generation WLAN etc. are proceeding to the form integrated into the All-IP core network. According to this development, Beyond 3G integrated into heterogeneous wireless access technologies must support the vertical handover and network to be used of several radio networks. However, unified management of each network is demanded since it is individually serviced. Therefore, in order to solve this problem this study is introducing the theory of Common Radio Resource Management (CRRM) based on Generic Link Layer (GLL). This study designs the structure and functions to support the vertical handover and propose the vertical handover algorithm of which policy-based and MCDM are composed between LTE and WLAN systems using GLL. Finally, simulation results are presented to show the improved performance over the data throughput, handover success rate, the system service cost and handover attempt number.

• Clinical and Experimental Pediatrics
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• v.54 no.2
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• pp.64-68
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• 2011

Purpose: The normal values for lung resistance and lung capacity of children, as determined by impulse oscillometry (IOS), are different for children of different ethnicities. However, reference values there is no available reference value for Korean preschool children have yet to be determined. The aim of the present study was to determine the normal ranges of IOS parameters in Korean preschool children. Methods: A total of 133 healthy Korean preschool children were selected from 639 children (aged 3 to 6 years) who attended kindergarten in Seongnam, Gyeonggi province, Korea. Healthy children were defined according to the European Respiratory Society (ERS) criteria. All subjects underwent lung function tests using IOS. The relationships between IOS value (respiratory resistance (Rrs) and reactance (Xrs) at 5 and 10 Hz and resonance frequency (RF)) and age, height, and weight were analyzed by simple linear and multiple linear regression analyses. Results: The IOS success rate was 89.5%, yielding data on 119 children. Linear regression identified height as the best predictor of Rrs and Xrs. Using stepwise multiple linear regressions based on age, height, and weight, we determined regression equations and coefficients of determination ($R^2$) for boys ($Rrs_5=1.934-0.009{\times}Height$, $R^2$=12.1%; $Xrs_5=0.774+0.006{\times}Height-0.002{\times}Age$, $R^2$=20.2% and for girls $(Rrs_5=2.201-0.012{\times}Height$, $R^2$=18.2%; $Xrs_5=-0.674+0.004{\times}Height$, $R^2$=10.5%). Conclusion: This study provides reference values for IOS measurements of normal Korean preschool children. These provide a basis for the diagnosis and monitoring of preschool children with a variety of respiratory diseases.

• Journal of the Korean Arthroscopy Society
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• v.2 no.1
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• pp.51-58
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• 1998

Purpose : The purpose of this study was to compare the postoperative success and stability of arthroscopically assisted anterior cruciate ligament(ACL) reconstructions using the central one third bone patellar tendon bone(BPB) autograft versus a quadrupled semitendinosus/gracilis(ST) autograft in patients with "isolated" ACL tears. Materials & Methods : A strict criteria to identify isolated ACL tears was used which included : no previous surgery, no other ligamentous injury, no history of patellofemoral symptoms, no patellofemoral malalignment, no meniscal pathology, no chondromalacia or chondral injury and no limitation of motion of the injured knee. 30 patients (15 BPB, 15 ST) with a mean age of 27.4 years were available for a mean follow up of 18 months (between 12 months and 26 months). Preoperatively, there was no significant difference between the two groups with respect to age, sex and degree of laxity. Results : Postoperatively, we couldn't find significant differences between the two groups with respect to subjective Lysholm score, objective laxity including Lachman test, pivot shift test and KT-2000 measurements. Mean side to side difference of KT-2000 scores at 20lbs were 1.5mm for the BPB group and 1.4mm for the ST group. Positive Lachman test was found in 26.7% and 33.3% and positive pivot shift was found in 20% and 33.3% of the patients in the BPB and ST groups, respectively. Anterior knee pain (33.3%) was more common in the BPB group. There were 80% of the patients in both groups above nearly normal grade according to the IKDC grade. Conclusions : In patients with "isolated" ACL tears, the overall results, ligamentous stability for the patellar tendon and the quadrupled semitendinosus/gracilis were comparable. We consider that the quadrupled autogenous hamstring tendon is a good alternative substitute in ACL reconstruction together with the bone patellar tendon bone.

• Korean Journal of Construction Engineering and Management
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• v.12 no.5
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• pp.146-154
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• 2011

Korean contractors have been maintained sustainable growth since entering into overseas construction market for the first time in 1960' s. In 2010, Korean contractors ordered 761 billion (USD) from overseas markets. Especially, billion (USD) were earned by Korean contractors in overseas plant construction market which account for more than 80% of the total amount by Korean contractors. Nevertheless, many Korean contractors are suffering from lack of technological competitiveness and construction management skills in the design phase compared with global leading contractors. These conditions have directly effect on the success of projects in terms of cost, duration, and quality. So, this study focused on identifying the risk factors and developing risk priority method for the design phase of LNG plant projects whose market is expanding. Research procedures were conducted by the following three steps. First, total 57 risk factors were identified in design phase through extensive literature reviews and experts survey. Second, the authors developed risk priority method which are more suitable for design phase of LNG plant projects by using three criteria, Probability(P), Impact(I), and Coordination Index(CI). Finally, the suitability of risk priority method and practical applicability were verified through expert survey and interview. Consequently, if korean contractors use the suggested risk factors and priority method based on their own know-how and experiences, then more reasonable and rational risk management will be conducted in the design phase of LNG plant projects.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.9 no.2
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• pp.45-60
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• 2014

In recent year's we have seen that due to education and social position there has been a significant increase in the number of women engaging in entrepreneurial activities. Concurrently research into the activities of women currently engaged in entrepreneurial activities has increased. This research has focused on the individuals themselves, their motivations and the performance of their ventures but there is not enough systematic research on the subject. Therefore it is necessary expand the criteria of the current research to examine every aspect of how these emergent entrepreneurs operate and to provide others with the same goals the appropriate skills and knowledge needed to succeed. This study wants to identify and evaluate the psychological, environmental and personal characteristics that these women possess and to assess the impact these factors have on the level of their success. This study will focus on those women who were empirical in their methods as this lends itself better to a detailed systematic analysis. It will examine the concept of entrepreneurial self-efficacy with regard to how they searched, planned, marshaled and implemented steps to influence the environmental and personal factors that affected them. In addition the searching phase of entrepreneurial self-efficacy directly influences entrepreneurial motivation and thus performance. The results of this study will suggest that as Korean women's interest in entrepreneurship grows it will have wide reaching theoretical implications and affect the direction of the policy that supports it.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.27 no.2
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• pp.51-80
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• 2016

Recently in accordance with Government 3.0 policy, public data is being released in large quantities and entrepreneurs are succeeding in utilizing this policy to develop products and apps that increase the convenience of the people to use the information. As libraries belong to the public domain, libraries must open a variety of data to the public in accordance with the Government 3.0 policy, and make the various applications utilizing the data. Therefore, this study investigated the government 3.0 Policy, classified the success cases of the applications according to specific criteria, identified data having high availability from the library data, and tried to discover data that can increase the utilization value through the library from other subject areas. An awareness survey was conducted of librarians of the University and Special Library and the results are as follows: First, librarians' awareness about the Government 3.0 was more than the average of 3.6, whereas for the initiatives presented in 3.0. Second, those responding that the government 3.0 policy would have a positive effect on libraries were six times higher than those responding negatively. Third, the respondents listed the ways that the policy can be effectively utilized in the library, in order, as providing to the user public open data classified by topic, providing user education about utilizing method of public open data, and privacy-related user education regarding open data utilization. Fourth, there was overall agreement by the respondents that public open data would be helpful in improving the library's changing role and image, with 60% responding in a positive way.

• Journal of Korean Neurosurgical Society
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• v.30 no.10
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• pp.1193-1199
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• 2001

Objectives : The goal of operation for degenerative lumbar diseases is to relieve radiculopathy and low back pain and to prevent further degeneration. The authors analyzed the surgical results of posterior lumbar interbody fusion(PLIF) and $0^{\circ}$ fixation to evaluate the proper treatment policy in spinal stenosis, degenerative spondylolisthesis and low grade isthmic spondylolisthesis. Material and Methods : The authors performed PLIF on 92 patients and $0^{\circ}$ fixation on 138 patients with spinal stenosis, degenerative spondylolisthesis and low grade isthmic spondylolisthesis. We retrospectively studied clinical outcomes and subjective satisfaction of these patients by several criteria such as visual analog scale(VAS), Prolo's economic and functional outcome scale, medication usage after operation and questionaire for overall outcome. Result : Pre- and postoperative VAS on back pain and leg pain showed decrease of pain from 6.5, 6.7 to 2.2, 2.4 in PLIF group and from 7.0, 7.2 to 2.5, 2.7 in $0^{\circ}$ fixation group. Excellent and good outcomes on Prolo's scale were 81.5% in PLIF group and 82.6% in $0^{\circ}$ fixation group. Medication usage after operation was reduced in 79.3% of PLIF group and in 78.3% of $0^{\circ}$ fixation group. Patients' self-reported overall success of their procedure showed 82% in PLIF group and 84% in $0^{\circ}$ fixation group. Conclusion : Both PLIF and $0^{\circ}$ fixation showed good outcomes and provided biomechanically stable fusion in spinal stenosis, degenerative spondylolisthesis and low grade isthmic spondylolisthesis. Therefore, only PLIF seems necessary and considered a proper surgical treatment for these disorders.