• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.1
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• pp.8-15
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• 2018

New methodology for probabilistic reliability based grid expansion planning of HVDC in power system including Wind Turbine Generators(WTG) is developed in this paper. This problem is focused on scenario based optimal selection technique to decide best connection bus of new transmission lines of HVDC in view point of adequacy reliability in power system including WTG. This requires two kinds of modeling and simulation for reliability evaluation. One is how is reliability evaluation model and simulation of WTG. Another is to develop a failure model of HVDC. First, reliability evaluation of power system including WTG needs multi-state simulation methodology because of intermittent characteristics of wind speed and nonlinear generation curve of WTG. Reliability methodology of power system including WTG has already been developed with considering multi-state simulation over the years in the world. The multi-state model already developed by authors is used for WTG reliability simulation in this study. Second, the power system including HVDC includes AC/DC converter and DC/AC inverter substation. The substation is composed of a lot of thyristor devices, in which devices have possibility of failure occurrence in potential. Failure model of AC/DC converter and DC/AC inverter substation in order to simulate HVDC reliability is newly proposed in this paper. Furthermore, this problem should be formulated in hierarchical level II(HLII) reliability evaluation because of best bus choice problem for connecting new HVDC and transmission lines consideration. HLII reliability simulation technique is not simple but difficult and complex. CmRel program, which is adequacy reliability evaluation program developed by authors, is extended and developed for this study. Using proposed method, new HVDC connected bus point is able to be decided at best reliability level successfully. Methodology proposed in this paper is applied to small sized model power system.

• The Journal of Advanced Prosthodontics
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• v.3 no.3
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• pp.166-171
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• 2011

PURPOSE. The purpose of this study is to evaluate and compare the shear bond strength of the gingiva-colored composite resin and the tooth-colored composite resin to porcelain, metal and zirconia. MATERIALS AND METHODS. Sixty cylindrical specimens were fabricated and divided into the following 6 groups (Group 1-W: tooth-colored composite bonded to porcelain, Group 1-P: gingiva-colored composite bonded to porcelain, Group 2-W: tooth-colored composite bonded to base metal, Group 2-P: gingiva-colored composite bonded to base metal, Group 3-W: tooth-colored composite bonded to zirconia, Group 3-P: gingiva-colored composite bonded to zirconia). The shear bond strength was measured with a universal testing machine after thermocycling and the failure mode was noted. All data were analyzed using the two-way analysis of variance test and the Bonferroni post-hoc test at a significance level of 0.05. RESULTS. The mean shear bond strength values in MPa were 12.39, 13.42, 8.78, 7.98, 4.64 and 3.74 for Group 1-W, 1-P, 2-W, 2-P, 3-W and 3-P, respectively. The difference between the two kinds of composite resin was not significant. The shear bond strength of Group 1 was the highest and that of Group 3 was the lowest. The differences among Group 1, 2 and 3 were all significant (P<.05). CONCLUSION. The shear bond strength of the gingiva-colored composite was not less than that of the tooth-colored composite. Thus, repairing or fabricating ceramic restorations using the gingiva-colored composite resin can be regarded as a practical method. Especially, the prognosis would be fine when applied on porcelain surfaces.

• Journal of the Korean Data and Information Science Society
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• v.26 no.6
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• pp.1271-1281
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• 2015

Competing risk analysis is widely applied to analyze a failure time with more than two causes. This paper discusses the application of a competing risk model to a economic activity state of workers with occupational injuries. In particular, main interest is to estimate the distribution of restarting time two kinds of economic activities, (i) returning to original working place and (ii) finding a new job. In this paper, we applied a cumulative incidence function to evaluate their patterns under several individual factors and working place's factor. Furthermore, a subdistributional regression model is applied to estimate the effect of these factors on the returning time. According to result, worker with higher education, younger age and longer working period had a higher chance to return an original working place while one with more severe injuries and skilled laborer had longer returning time to an original working place.

• Nuclear Engineering and Technology
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• v.39 no.3
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• pp.215-220
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• 2007

The existing flooding Probabilistic Safety Analysis(PSA) was updated to reflect the Korean plant specific operating experience data into the flooding frequency to improve the PSA quality. Both the Nuclear Power Experience(NPE) database and the Korea Nuclear Pipe Failure Database(NuPIPE) databases were used in this study, and from these databases, only the Pressurized Water Reactor(PWR) data were used for the flooding frequencies of the flooding areas in the primary auxiliary building. With these databases and a Bayesian method, the flooding frequencies for the flooding areas were estimated. Subsequently, the Core Damage Frequency(CDF) for the flooding PSA of the Ulchin(UCN) unit 3 and 4 plants based on the Korean Standard Nuclear Power Plant(KSNP) internal full-power PSA model was recalculated. The evaluation results showed that sixteen flooding events are potentially significant according to the screening criterion, while there were two flooding events exceeding the screening criterion of the existing UCN 3 and 4 flooding PSA. The result was compared with two kinds of cases: (1) the flooding frequency and CDF from the method of the existing flooding PSA with the PWR and Boiled Water Reactor(BWR) data of the NPE database and the Maximum Likelihood Estimate(MLE) method and (2) the flooding frequency and CDF with the NPE database(PWR and BWR data), NuPIPE database, and a Bayesian method. From the comparison, a difference in CDF results was revealed more clearly between the CDF from this study and case (2) than between case (1) and case (2). That is, the number of flooding events exceeding the screen criterion further increased when only the PWR data were used for the primary auxiliary building than when the Korean specific data were used.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.774-780
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• 1999

The study of bond behavior between concrete and rebar has been performed for a long time. On this study, we tried to analysed variation of bond behaviors quantitatively with varying the strength of concrete. Bond stress which observed below the neutral surface of beam and at connecting part of beam and column is affected by various bond parameters. Resistance of deformed bars which embedded in concrete to the pullout force is divided 1) chemical adhesive force 2) frictional force 3) mechanical resistance of ribs to the concrete and these horizontal components of resistance is being bond strength. We selected the most common and typical variable which is concrete strength among various variables. So we used two kinds of concrete strength like as 25MPa(NSC) and 65MPa(HSC). Tension Test was performed to verify how bond behavior varied with two kinds of concrete strength. Concentration of bond stress was observed at load-end commonly in Tension Test of the initial load stage. At this stage stress distribution was almost coincident at each strength. As tension load added, this stress distribution had difference gradually and movement of pick point of bond stress to free-end and central section was observed. This tendency was observed at first and moving speed was more fast in NSC. At the preceeding result the reason of this phenomenon is considered to discretion of chemical adhesion and local failure of concrete around rebar in load-end direction. Especially, when concrete strength was increased 2.6 times in tension test, ultimate bond strength was increased 1.45 times. In most recent used building codes, bond strength is proportioned to sqare root of concrete compressive strength but comparison of normalized ultimate bond strength was considered that the higher concrete strength is, the lower safety factor of bond strength is in each strength if we use existing building codes. In Tension Test, in case of initial tensile force state, steel tensile stress of central cross section is not different greatly at each strength but tensile force increasing, that of central cross section in NSC was increased remarkably. Namely, tensile force which was shared in concrete in HSC was far greater than that of concrete in NSC at central section.

• Tunnel and Underground Space
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• v.23 no.5
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• pp.413-427
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• 2013

Thin Spray-on Liners(TSLs) based on polymer materials have been considered as an alternative to shotcrete and wire mesh in relatively fair rock conditions, and used in mines since 1990s. Nevertheless, Few experimental studies on their mechanical properties necessary for the evaluation of their bearing capacities as a support member have been carried out. In this study, tensile and bond strengths of two kinds of TSLs with different material compositions were measured at the age of 7 days. In addition, two kinds of bending tests proposed by EFNARC (2008) to simulate representative failure mechanisms of TSLs were carried out on the same materials and curing age as in tension and pull-out tests. From the tests, tensile strength of a TSL is shown to increase as its content of polymer is higher. In contrast, its bond strength seems to be in inverse proportion to its polymer content. Especially, the TSL material in which a cementitious component is included with relatively smaller polymer content shows a faster hardening characteristic which results in higher resistance to de-bonding between a TSL and a substrate. As a result, it is shown that the performance of TSLs might be dependent upon its corresponding polymer content.

• Archives of Plastic Surgery
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• v.35 no.2
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• pp.174-180
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• 2008

Purpose: While radiotherapy remains an essential part of the multidisciplinary treatment of cancers, it may cause unwanted consequences such as tissue break down and chronic non-healing wounds as a result of hypoxia, hypovascularity, and hypocellularity. The conservative treatment of osteoradionecrosis was effective only in the early stages or has a limited result. The surgical treatment of osteoradionecrosis includes various local fasciocutaneous flaps, local myocutaneous flaps and different kinds of free flaps with cancellous bone graft or alloplastic material after removal of all devitalized tissue. This study reviews recent cases of osteoradionecrosis in Severance hospital and investigates the use of various flaps for reconstruction of osteoradionecrosis. Methods: From 2000 to 2006, a total of 29 patients, nine men and twenty women with a mean age of 60.4 years were identified and included in the study. Fasciocutaneous flaps were used on 7 patients and myocutaneous flaps were used on the remaining patients. Mean follow-up period was 10.4 months. Results: In the fasciocutaneous flap group, we noted two complications including total flap failure and a partial flap necrosis. In the myocutaneous flap group, four complications were noted including a partial flap necrosis and 3 cases of wound dehiscence. Considering the complications noted in this study, the natural history of progression to flap necrosis appeared to follow the following sequence of events: marginal flap necrosis, infection, wound dehiscence, flap floating and partial flap necrosis, serially. Conclusion: Successful surgical treatment of osteoradionecrosis includes wide radical debridement and reconstruction with a well vascularized flap like myocutaneous flap or fasciocutaneous flap.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.5
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• pp.265-272
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• 2010

Follicular cystic ovary (FCO) is one of the most frequently diagnosed ovarian diseases and is a major cause of reproductive failure in mammalian species. However, the mechanism by which FCO is induced remains unclear. Genetic alterations which affect the functioning of many kinds of cells and/or tissues could be present in cystic ovaries. In this study, we performed a comparison analysis of gene expression in order to identify new molecules useful in discrimination of bovine FCO with follicular cystic follicles (FCFs). Normal follicles and FCFs were classified based on their sizes (5 to 10 mm and $\geq25mm$). These follicles had granulosa cell layer and theca interna and the hormone $17{\beta}$-estradiol ($E_2$)/ progesterone ($P_4$) ratio in follicles was greater than one. Perifollicular regions including follicles were used for the preparation of RNA or protein. Differentially expressed genes (DEG) that showed greater than a 2-fold change in expression were screened by the annealing control primer (ACP)-based PCR method using $GeneFishing^{TM}$ DEG kits in bovine normal follicles and FCFs. We identified two DEGs in the FCFs: ribosomal protein L15 (RPL15) and microtubule-associated protein 1B (MAP1B) based on BLAST searches of the NCBI GenBank. Consistent with the ACP analysis, semi-quantitative PCR data and Western blot analyses revealed an up-regulation of RPL15 and a down-regulation of MAP1B in FCFs. These results suggest that RPL15 and MAP1B may be involved in the regulation of pathological processes in bovine FCOs and may help to establish a bovine gene data-base for the discrimination of FCOs from normal ovaries.

• Bulletin of the Korean Chemical Society
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• v.33 no.4
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• pp.1123-1127
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• 2012

P-gp (P-glycoprotein) is a member of the ATP binding cassette (ABC) family of transporters. It transports many kinds of anticancer drugs out of the cell. It plays a major role as a cause of multidrug resistance (MDR). MDR function may be a cause of the failure of chemotherapy in cancer and influence pharmacokinetic properties of many drugs. Hence classification of candidate drugs as substrates or nonsubstrate of the P-gp is important in drug development. Therefore to identify whether a compound is a P-gp substrate or not, in silico method is promising. Recursive Partitioning (RP) method was explored for prediction of P-gp substrate. A set of 261 compounds, including 146 substrates and 115 nonsubstrates of P-gp, was used to training and validation. Using molecular descriptors that we can interpret their own meaning, we have established two models for prediction of P-gp substrates. In the first model, we chose only 6 descriptors which have simple physical meaning. In the training set, the overall predictability of our model is 78.95%. In case of test set, overall predictability is 69.23%. Second model with 2D and 3D descriptors shows a little better predictability (overall predictability of training set is 79.29%, test set is 79.37%), the second model with 2D and 3D descriptors shows better discriminating power than first model with only 2D descriptors. This approach will be used to reduce the number of compounds required to be run in the P-gp efflux assay.

• Journal of Acupuncture Research
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• v.17 no.2
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• pp.85-93
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• 2000

We came to the conclusion after considering all the information from many kinds of books on the circulation courses, cross-link points, functions and the symptoms of disease of Chongmai. The results were as follows : 1. The Chongmai that starts from a Uterus flows to Dazhu through the inside of vertebra after joining Renmai and Duimai at Huiyin. The Chongmais up-line that comes out from Qichong into a surface of body arrives and is scattered at a chest through an abdomen. One strand of them goes upward again and is connected to a throat and lips area. After coming out from Qichong, separated down-line is divided into two parts when it arrives a inner part of a heel through the inner part of a leg. One is for an instep, the other is for the sole of a foot. 2. We call it "Sea of Twelve Meridians" or "Meridian's Sea". Because Chongmai controls all of Meridian by acquired "Basic energy" as getting Stomach's energy, Kidney's energy and air-energy, and there are responsible of physiological phenomenon control. And also we name it "Sea of Blood", because it starts from and provides a nutrition to Uterus. 3. All of these four Meridian such as Renmai, Kidney Meridian, Stomach Meridian and Spleen Meridian are ones that flow around the part of a chest and an abdomen. Chongmai makes energy and blood circulation of a chest and an abdomen be stronger and be controlled. Therefore it makes viscera, bowels and body surface be warm and given a nutrition. So Chongmai becomes "Sea of Viscera and Bowels". 4. Chongmai provides a nutrition for ligament and muscle and makes legs get warm as making energy and blood circulate from head to foot. If Chongmai is energetic, hair is completely easy to grow. 5. To see in pathological phase, Chongmais failure or weakness causes like a chest pain, stomachache, heart attack, a menstrual irregularity and sterility and so on. And also if Chongmai is damaged, it happens that giving a nutrition for lips area is stopped, and then mustache doesn't grow any more.