• The KIPS Transactions:PartC
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• v.9C no.4
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• pp.589-596
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• 2002

Tn the data transmission service of the mobile host, it is needed to reduce the bandwidth and to make a reliable error recovery. there are two appropriate methods in that. One is FEC which retransmits the parity of error recovery, in case of happening of the loss after forming the parity of error recovery by grouping original data. The other is local recovery based on server which can block the implosion of transmission. The use of FEC and local recovery based on server at the same time enables the reliable multicast. This paper suggests algorithm that recovers the loss by FEC and local recovery based on server through the solution of the problems about triangle routing, tunnel convergence by dividing mobile host into two parts-the sender and the receiver. This model about the loss of algorithm tested the efficiency of performance by the homogeneous independent loss, the heterogeneous independent loss, the shared source link loss model. The suggested algorithm confirms effectiveness in the environment where there are much data and many receivers in mobile host.

• Journal of the Korean Society for Railway
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• v.19 no.2
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• pp.234-242
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• 2016

In express operation plans for urban trains, it is effective for the reduction of the number of sidetracks to apply a high performance train that has improved acceleration/deceleration ability and a regular train to local and express trains, respectively. In this research, based on a plan to use a high performance train for a local train, an optimization methodology is suggested to reduce the number of sidetracks and the operation time of the local train simultaneously. The optimization solver applied in this research is a genetic algorithm; headway, location of sidetrack and waiting time at the sidetrack are considered as design variables in the optimization problem. Consequently, by applying this system to Seoul metro line no.7, the effect of the suggested methodology was verified by obtaining the proper optimum solution.

• Journal of Environmental Impact Assessment
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• v.21 no.1
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• pp.15-24
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• 2012

The purpose of this study is to understand the process and characteristics of social impact caused by development projects through research and analysis on issues presented during development projects carried out in Korea. Furthermore, on the basis this analysis, this study proposes possible improvement measure environmental impact assessment for minimizing social impact of development projects in the future. Issues related to development projects are generated mainly by the following three causes. Initial social impact can occur when a development project directly causes certain changes in natural, living and social environment. Operational problems related to assessment are another cause of social impact, and it can also occur when changes in natural and living environment work in tandem with social environment sphere. Social impact of development projects is not brought about solely by changes in social environment, but is the result of interaction of factors such as changes in social, natural, living environment and problems related to assessment or operation/management. As to why the current environmental impact assessment could not provide satisfactory solution to the issues mentioned above, this study suggests the following reasons: limitations of assessment method used in social environment category, difficulties in defining assessment criteria, limitations inherent in criterion referenced assessment method, insufficient issue-making in local community, and lack of participation on the part of local residents. Possible solutions for these limitations are as follows: 1) To identify local issues in social environment category through participation of local experts in scoping stage, 2) To adopt deliberative method for local participation, 3) To utilize social survey technique.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.602-606
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• 2008

LCD is supplied light by BLU(Back Light Unit) and the light represents color by each color filter. Also LCD adjusts the amount of light by controlling liquid crystal between the glass of upper plate and one of lower. However, it is impossible to completely exclude light due to the structural and physical characteristic of liquid crystal. Therefore, on transfering light through optical sheet and liquid crystal, many problems are generated. They are related with energy efficiency and get effective for the contrast of LCD to have lower contrast ratio than other display devices. To solve the problems, many techniques have been studied and developed but don't exist keys to solution for them. Among methods, local dimming is one example to be applied to LCD. In this paper we propose image processing algorithm for local dimming of BLU of LED used as light source. The proposed algorithm extracts maximum luminance signal and lights using each extracted signal on segmented region of BLU. Also the proposed algorithm generates image signal in corresponding to luminance of the segmented region and supplies them with LCD panel to represent image with improving luminance ratio.

• Journal of Dental Anesthesia and Pain Medicine
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• v.18 no.6
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• pp.367-373
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• 2018

Background: Fear of local anesthesia (LA) is a significant impediment to dental care as many patients delay or avoid treatment to avert pain. Computer-controlled local anesthetic delivery system (CCLAD), with constant and controlled rate of flow, present a painless alternative. The present study aimed to compare anxiety and pain perceived with conventional and computerized systems, for different stages of anesthesia delivery when administering various nerve blocks. Methods: One hundred patients requiring bilateral LA participated in the study. One side was anesthetized using one system and the contralateral side was anesthetized using the other, in two separate appointments. Patients assigned anxiety scores on a 5-point scale and used the visual analogue scale (VAS) for pain determination at needle insertion, during delivery of anesthetic solution, immediately after injection, and at the end of the periodontal procedure. Each patient's preference for the delivery system of future injections was also recorded. Results: Patients reported significantly lower anxiety levels with CCLAD compared to the syringe. Significantly lower mean VAS scores for anesthesia deposition, pain immediately after, and at the end of the periodontal procedure were also noted. However, pain at needle insertion was comparable between the two systems, with no statistical significance. Overall, 64.4% patients preferred CCLAD for future anesthesia. Conclusion: Lower pain perceived with CCLAD and higher preference for the system suggest that CCLAD should replace conventional syringes to allow pain-free dental treatment.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.4
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• pp.203-209
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• 2023

Harmony search(HS) does not use the evaluation of individual harmony when referring to HM when constructing a new harmony, but particle swarm optimization(PSO), on the contrary, uses the evaluation value of individual particles and the evaluation value of the population to find a solution. However, in this study, we tried to improve the performance of the algorithm by finding and identifying similarities between HS and PSO and applying the particle improvement process of PSO to HS. To apply the PSO algorithm, the local best of individual particles and the global best of the swam are required. In this study, the process of HS improving the worst harmony in harmony memory(HM) was viewed as a process very similar to that of PSO. Therefore, the worst harmony of HM was regarded as the local best of a particle, and the best harmony was regarded as the global best of swam. In this way, the performance of the HS was improved by introducing the particle improvement process of the PSO into the HS harmony improvement process. The results of this study were confirmed by comparing examples of optimization values for various functions. As a result, it was found that the suggested HS-PSO was much better than the existing HS in terms of accuracy and consistency.

• Journal of the Korean institute of surface engineering
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• v.53 no.2
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• pp.59-66
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• 2020

Effects of Na₂SiO₃ concentration added into 0.1 M NaOH + 0.05 M NaF solution on the formation behavior and properties of PEO films on AZ91 Mg alloy were investigated under 1200 Hz of alternating current (AC) by voltage-time curves, in-situ observation of arc generation behavior and measurements of film thickness, surface roughness and micro vickers hardness. In the absence of Na₂SiO₃ in the 0.1 M NaOH + 0.05 M NaF solution, about 4 ㎛ thick PEO film was formed within 1 min and then PEO film did not grow but white spots were formed by local burning. Addition of Na₂SiO₃ up to 0.2 M caused more increased formation voltage and growth of PEO film with uniform generation of arcs. Addition of Na₂SiO₃ from 0.2 M to 0.4 M showed nearly the same voltage-time behavior and uniform arc generation. Addition of Na₂SiO₃ more than 0.5 M resulted in a decrease of formation voltage and non-uniform arc generation due to local burning. PEO film growth rate increased with increasing added Na₂SiO₃ concentration but maximum PEO film thickness was limited by local burning if added Na₂SiO₃ concentration is higher than 0.5 M. Surface roughness of PEO film increased with increasing added Na₂SiO₃ concentration and appeared to be proportional to the PEO film thickness. PEO film hardness increased with increasing added Na₂SiO₃ concentration and reached a steady-state value of about 930 H_V at more than 0.5 M of added Na₂SiO₃ concentration.

• Journal of Oral Medicine and Pain
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• v.30 no.1
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• pp.25-34
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• 2005

A trigger point injection (TPI) has been reported to have an immediate analgesic effect, and to be one of the most widely employed treatment methods of myofascial pain. There are normal saline, local anesthetics, and steroids as the solutions frequently used in TPI. They can be used separately or in combination. Local anaesthetics have myotoxicity in proportion to its concentration. The purpose of this study was to evaluate microstructural changes in point of the myotoxic effects of the combined solution of lidocaine and dexamethasone (a local anesthetic and a steroid) after being injected into the muscle of BALB/c mice. And this study tested solutions with various concentration separately and in combination, to find out proper concentration of solution without muscular tissue damage. This study shows that lidocaine and dexamethasone combination is not histologically myotoxic in case of the concentration of lidocaine less than 1.5%. Also it is suggested from this study that this combined solution will have an analgesic and anti-inflammatory effect. Hereafter continuous study should be performed to reveal that these results can be applied to human when lidocaine and dexamethasone combination is used as an injection modality of TrP treatment.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.9
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• pp.1148-1156
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• 2000

The QUICK scheme for convection terms is modified for unstructured finite volume method by using linear reconstruction technique and validated through the computation of two well defined laminar flows. It uses two upstream grid points and one downstream grid point in approximating the convection terms. The most upstream grid point is generated by considering both the direction of flow and local grid line. Its value is calculated from surrounding grid points by using a linear construction method. Numerical error by the modified QUICK scheme is shown to decrease about 2.5 times faster than first order upwind scheme as grid size decreases. Computations are also carried out to see effects of the skewness and irregularity of grid on numerical solution. All numerical solutions show that the modified QUICK scheme is insensitive to both the skewness and irregularity of grid in terms of the accuracy of solution.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.811-814
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• 1997

In this paper, the torque optimization of a kinematically redundant manipulator for minimizing the torque demands is discussed. The minimum torque solution based on a local optimization has been known to encounter the instability problem and then the global torque optimization was suggested as one of the alternatives. Herein, by adopting the infinity-norm rather than the 2-norm for the magnitude of torques, we are to propose a new cost function more advantageous to the avoidance of torque limits. By the way, a solution to the global torque optimization formulated with the new cost function can not be obtained by the previous methods due to their difficulties such as inability to treat discontinuous cost functions and various constraints on the joint variables. Thus, to overcome those deficiencies, we are developing a new approach using the dynamic programming. The effectiveness of the proposed method is shown through simulation examples for a 3-link planar redundant manipulator.