• 한국자동차공학회논문집
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• 제2권4호
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• pp.18-26
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• 1994

The buckling characteristics of I - shaped columns which are composed of thin web and equal upper/lower flange plates are generally classified into the local and global modes. In this paper, its local buckling problem has been formulated on the basis of the assumed buckling modes using the finite element method for beams and plates. The effects of local bucklings are studied for various size rations and end conditions of I-shaped columns. The calculated results are comparatively well consistent with values obtained from the existing studies. The global buckling characteristics calculated by the present method are in good agreement with the classical rigid web solution

• Journal of Dental Anesthesia and Pain Medicine
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• 제24권1호
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• pp.37-45
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• 2024

Background: The delivery of profound local anesthetics helps children receive successful treatment by reducing fear, anxiety, and discomfort during dental procedures. Local anesthetic injections are the most anticipated stimuli in dental surgery. Children's perceptions of pain can be altered by applying cryotherapy to precool the oral mucosa or by diverting their minds through taste distractions before administering local anesthetic injections. This study aimed to evaluate the efficacy of cryoanesthesia and xylitol sweet-tasting solution at the injection site in 7-10-year-old children. Methods: A total of 42 participants, aged 7-10 years, who underwent dental treatment requiring local anesthesia, were enrolled in the study. The children were randomly divided into three groups. In group I, sterile water was held in the mouth for 2 minutes before anesthetic administration, similar to group II, and in group III, a xylitol sweet-tasting solution was used for 2 minutes before needle insertion. The analysis of pain perception was carried out based on the Visual Analog Scale (VAS) and the Sound, Eyes, and Motor (SEM) scale. For VAS analysis, a one-way analysis of variance (ANOVA) was performed for intergroup comparison, and a post hoc Tukey test was performed for subgroup analysis. For the categorical SEM scale, the Kruskal-Wallis test followed by the post hoc test was performed for intergroup comparison. Where a P value of <0.05 was considered statistically significant at 95% confidence intervals. Results: Cryoanesthesia significantly reduced pain scores on VAS (4.21 ± 1.42) when compared to those on VAS with xylitol sweet-tasting solution (5.50 ± 1.40) and that with sterile water (6.14 ± 2.47). Intergroup comparison of the VAS scores among the three groups was performed using one-way ANOVA, which demonstrated statistically significant differences (P value <0.026) on the VAS scale. Intergroup comparison of the SEM scale was performed using the Kruskal-Wallis test, followed by post hoc comparison, which exhibited statistically significant differences (P < 0.007) among the three groups for the SEM scale. Conclusion: Cryoanesthesia demonstrated higher efficacy in reducing injection pain than that exhibited by the xylitol sweet-tasting solution.

• ETRI Journal
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• 제37권3호
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• pp.533-540
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• 2015

In wireless localization, several linear closed-form solution (LCS) methods have been investigated as a direct result of the drawbacks that plague the existing iterative methods, such as the local minimum problem and heavy computational burden. Among the known LCS methods, both the direct solution method and the difference of squared range measurements method are considered in this paper. These LCS methods do not have any of the aforementioned problems that occur in the existing iterative methods. However, each LCS method does have its own individual error property. In this paper, a hybrid LCS method is presented to reduce these errors. The hybrid LCS method integrates the two aforementioned LCS methods by using two check points that give important information on the probability of occurrence of each LCS's individual error. The results of several Monte Carlo simulations show that the proposed method has a good performance. The solutions provided by the proposed method are accurate and reliable. The solutions do not have serious errors such as those that occur in the conventional standalone LCS and iterative methods.

• 한국시스템다이내믹스연구
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• 제15권2호
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• pp.51-74
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• 2014

Over the past few years Korea has achieved rapid economic growth, while the deepening polarization of income has negatively affected Korea economy and society. It can be the reason of this negative effect on economy that the increased income by the economic growth has not been distributed socially, but overly focused on one part of social class. One of the important and powerful solution of social polarization could be the strengthening of the income distribution. In these circumstances, the social interest and discussion on the universal welfare system and on the basic income as the means of income redistribution have been increasing. In this study, a system dynamic analysis was conducted to find how an universal cash payment as basic income providing cash benefits impacts on the promotion of consumption in private sector, of local jobs and of local economic organizations. Recently, the poor energy consumption ability of energy poverty became one of the social problems. Also it was analysed how an energy payment-in-kind as basic income influences on the energy consumption of the region, the energy production capacity, the promotion of local energy. The universal cash payment and energy payment-in-kind as the basic income policy showed similar and positive effects on the local economy system and on the local energy system respectively.

• 디지털융복합연구
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• 제12권3호
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• pp.37-53
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• 2014

지방자치단체에 의한 감사는 지방자치단체의 내부 통제를 개선하고 자신들의 정책을 진단하여 관리능력을 향상시키며 정책 오류를 예방하는 역할을 한다. 그러나 자기기관 감사와 검사 수준은 매우 낮은 실정이다. 이는 전문가 수준의 직원보다 빈번한 순환 보직으로 실무 경험이 미흡한 감사요원을 배치하기 때문이다. 이러한 문제를 극복하고 지방자치단체의 자체감사기능을 강화하기 위하여 여러 가지 감사환경을 고려한 솔루션으로 새로운 시스템을 제안한다. 본 연구는 지방감사의 문제점을 찾아 자체 감사평가시스템의 새로운 체계를 제시하였다. 자체전자감사평가시스템은 자체기관 감사 및 검사를 강화하여 궁극적으로 지방정부의 역량을 강화시킬 것이다.

• 한국지구과학회지
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• 제29권5호
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• pp.437-445
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• 2008

We analyzed fault plane solutions of the recent twenty-two earthquakes which occurred from 2004 to 2006 in the central part of the Korean Peninsula by using P- and S-wave polarities along with SH/P amplitude ratios. The fault plane solution shows that strike-slip fault is dominant here, especially for the events with local magnitude equal to or greater than 3.0. However, some events with local magnitude less than 3.0 show normal fault or strike-slip fault with normal components. In the case of strike-slip fault, its orientation is almost in the direction of NNE-SSW to NE-SW almost parallel to the general trend of faults, while the compressional axis of the stress field trends ENE to E-W. The result is almost consistent with the stress field in and around the Korean peninsula, as reported previously. We cannot give any appropriate explanations to the normal faulting events along the western offshore and inland areas whether it is related to the local stress changes or tectonically unidentified extensional structures. Thus, an extension of investigations is desirable to clarify the cause of such phenomena.

• Journal of Advanced Marine Engineering and Technology
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• 제27권6호
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• pp.714-720
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• 2003

Due to the electric power shortage in summer season and regulation of freon refrigerant, the application of gas absorption refrigeration and hot water systems are considerably increasing trend. But, this system consists of condenser, heat exchanger, supply pipe and radiator etc. which are easily corroded by acidity and dissolved oxygen and gases. In result, this system occurs scale attachment and corrosion damage like pitting and crevice corrosion. In this study, electrochemical polarization test of heat exchanger tubing material (copper, aluminium brass, 30% cupronickel(30% Cu-Ni)) was carried out in 60% lithium bromide solution at $95^{\circ}C$. As a result of polarization test, corrosion behavior by impressed potential and local corrosion. such as galvanic corrosion, pitting corrosion behavior, of tubing materials was investigated. The main results obtained are as follows: (1) The effect of pitting and crevice corrosion control of 30% cupronickel in 60% LiBr solution at $95^{\circ}C$ is very excellent. (2) Dissimilar metal corrosion of 30% cupronickel coupling to aluminium bronze is the most sensitive. (3) Current density behavior of tube materials by impressed potential is high in order of copper > aluminium brass > 30% cupronickel.

• Journal of Pharmaceutical Investigation
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• 제27권1호
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• pp.71-77
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• 1997

With the aim of improving periodontal regeneration efficacy, as a biodegradable local drug delivery device, drug releasing chitosan beads were prepared. Chitosan beads were prepared through the formation of intermolecular or intramolecular ionic interaction bewteen chitosan and sodium tripolyphosphate and were loaded with flurbiprofen. The mean diameter of the beads was $250\;{\mu}m$. Drug loading efficiency was improved by regulating the pH of tripolyphosphate solution. The drug release kinetics mainly depended upon the hydrophobic properties of the flurbiprofen, that is, the release of flurbiprofen showed initial burst with rapid release for the first day followed by a levelling off of the release rate. However, the release rate could be controlled by the formulation factor including the pH, concentration of the tripolyphosphate solution, gelation time, drug contents. From these results, flurbiprofen loaded chitosan beads were anticipated as biodegradable local drug delivery devices for periodontal regeneneration.

• 대한수학회논문집
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• 제33권2호
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• pp.677-693
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• 2018

In this work, we generalize a family of optimal eighth order weighted-Newton methods to Banach spaces and study its local convergence to approximate a locally-unique solution of a system of nonlinear equations. The convergence in this study is shown under hypotheses only on the first derivative. Our analysis avoids the usual Taylor expansions requiring higher order derivatives but uses generalized Lipschitz-type conditions only on the first derivative. Moreover, our new approach provides computable radius of convergence as well as error bounds on the distances involved and estimates on the uniqueness of the solution based on some functions appearing in these generalized conditions. Such estimates are not provided in the approaches using Taylor expansions of higher order derivatives which may not exist or may be very expensive or impossible to compute. The convergence order is computed using computational order of convergence or approximate computational order of convergence which do not require usage of higher derivatives. This technique can be applied to any iterative method using Taylor expansions involving high order derivatives. The study of the local convergence based on Lipschitz constants is important because it provides the degree of difficulty for choosing initial points. In this sense the applicability of the method is expanded. Finally, numerical examples are provided to verify the theoretical results and to show the convergence behavior.

• 한국인터넷방송통신학회논문지
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• 제19권5호
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• pp.73-78
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• 2019

본 논문은 NP-난제로 널리 알려진 최대 가중치 독립집합 문제에 대해 다항시간으로 풀 수 있는 규칙을 제시하였다. 기존에 알려진 분산형 알고리즘은 지역에서 최대 가중치 노드를 독립집합 원소로 결정하는 방법을 적용하였다. 그러나 지역에서 최대 가중치를 갖는 노드 단독이 아닌 보다 작은 가중치들을 갖는 노드들이 병합된 독립집합이 최대 가중치를 갖는 경우가 보다 빈번히 발생하여 기존에 알려진 방법으로는 최적 해를 구하지 못할 수도 있다. 이러한 문제점을 해결하기 위해, 본 논문에서는 지역에서 최대 가중치를 갖는 독립집합을 형성하는 방법을 제안하였다. 제안된 알고리즘을 다양한 망들에 적용한 결과, 기존에 알려진 알고리즘으로 구하지 못한 최적 해를 구할 수 있었다.