• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2356-2363
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• 2015

This study deals the optimization design with the simulation based design of a coil spring inserted into the lock nut for preventing the screw thread from loosening at the bolted joint when the high-strength steel bolt with the property class of 10.9 is used and the screw torque of 640 to 800 (Nm) is applied. In this study, structural analysis of assembly composed of bolt, nut and coil spring is carried out to evaluate its safety factors on the basis of the equivalent stress with commercial finite element analysis software. And the design strategy to extract the design improvement from these simulation results is established. An iterative process performed with the proposed design strategy is also proposed for improving the performance of the existing design. At the proposed procedure, the feasible design parameters using response surface method are found, and then these parameters are verified to be optimal or not by comparing with the response values and the simulation results obtained from the feasible parameters.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2370-2378
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• 2015

This paper proposes an algorithm using Lagrange interpolation method to realize trajectory planning for torque minimization of robot manipulators. For the algorithm, position constraints of robot manipulators should be given and the stability of robot manipulators should be satisfied. In order to avoid Runge's phenomenon, we set up time interpolation points using Chebyshev interpolation points. After that, we found suitable angle which corresponds to the points and then we got trajectories of joint's angle, velocity, acceleration using Lagrange interpolation method. We selected performance index for torque consumption optimization of robot manipulator. The method went through repetitive computation process to have minimum value of the performance index by calculated trajectory. Through the process, we could get optimized trajectory to minimize torque and performance index and guarantee safety of the motion for manipulator performance.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.3
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• pp.18-25
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• 2006

In order to perform system requirements quickly and accurately, an automatic design program of solid rocket motors(SRM) structure designated as the 'ProDes software' has been developed and verified. from given system design criteria and constraints, it has the capabilities to design, analysis, simulation and drawing process to greatly reduce the over 'design cycle time' and manpower of a project. The conception of the program is modular, and calculations are performed step by step allowing parametric design studies and providing final selected design goal. Each configurations of SRM components and joint types composed of various master models is obtained from the data base module of the library. Between the design results of the ProDes software and those of the previous detail design of the established motor showed good agreements.

• Journal of Convergence for Information Technology
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• v.10 no.11
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• pp.40-46
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• 2020

Safe security technology is required for the startup ecosystem according to the construction and service of a joint open platform in the financial sector. Financial industry standard open API recommends that payment-related fintech companies develop/apply additional security technologies to protect core API authentication keys in the mutual authentication process. This study proposes an enhanced API security protocol using multiple channels. It was designed in consideration of the compatibility of heterogeneous platforms by further analyzing the problems and weaknesses of existing open API related research. I applied the method of concealment to remove the additional security channels into a single channel of the existing security protocols. As a result of the performance analysis, the two-way safety of the communication session of the multi-channel and the security of the man-in-the-middle attack of the enhanced authentication key were confirmed, and the computational performance of the delay time (less than 1 second) in the multi-session was confirmed.

• Journal of Convergence for Information Technology
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• v.10 no.11
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• pp.332-339
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• 2020

This study aims to analyze problems and deduce improvement plans for information security support policies for SMEs in Korea. To this end, an effective support policy necessary for reinforcing cyber safety nets to enhance the level of information security of domestic SMEs based on the analysis results by analyzing the status and problems of the previous research review and analysis, the current status of information security of SMEs and the information security support policies of major SMEs at home and abroad. I would like to suggest improvement measures. Reinforcement of awareness, legal basis, voluntary capacity building, joint response system, professional manpower and budget support, cyber security construction, untact era support, and regional strategic industry security internalization were suggested. This can be used as the government's information security support policy to raise the level of information security of SMEs in preparation for the post Covid19.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.12 no.1
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• pp.13-27
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• 2017

Objectives: To evaluate and summarize the efficacy and safety of manual therapy in temporomandibular disorder(TMD). Methods: Ten databases (Pubmed, Cochrane, EMBASE, AMED, CINAHL, CNKI, and four Korean databases) were searched up to March 2017. Pain and range of motion(ROM) of temporomandibular joint were used as the primary outcome measure, and effective rates, dysfunction scale and adverse events were used as secondary outcome measures. The Cochrane risk of bias tool was used to evaluate the methodological quality. Results: 10 randomized controlled trials(RCTs) involving 603 participants were included. There were no significant differences between the two groups in comparison with placebo manual therapy group. In comparison with Wait-list and conventional treatment groups, manual therapy significantly alleviated pain and ROM. Five RCTs(50.0%) reported adverse events and there were no adverse cases by manual therapy. Conclusions: We found evidence that manual therapy may alleviate symptoms of patients with TMD. A positive effect was observed in comparison with conventional treatment and Wait-list, but no conclusion for the comparisons with placebo manual therapy. There is no evidence of worsening symptoms or causing adverse events.

• Journal of the Korean Society of Propulsion Engineers
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• v.2 no.3
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• pp.1-9
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• 1998

The exhaustion of fossil fuels and serious environmental pollution put the concern about non-po llution energy into the world. On the developments of technology, wind energy has been spotlighted as a non-pollution energy in many countries. This study has carried out the aerodynamic and structural design procedure of the lightweight composite rotor blades with an appropriate aerodynamic performance and structural strength for the 500㎾ medium class wind turbine system. The previous design, which is shell-spar structure, is redesigned to shell-spar- sandwich structure for light weight. Large deformation problem from light weight is examined by non-linear analysis. Local buckling occurred under lower stress than failure stress. The buckling analysis is accomplished to confirm the safety of the composite blade. The stress analysis around pin hole joint part at hub is carried out and it is confirmed that the pin hole is not failed. The results show that the resonance of redesigned blade does not happen in operation range.

• Korean Institute of Interior Design Journal
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• v.25 no.3
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• pp.90-101
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• 2016

The Homeshare program, which was introduced in 2012, has been implemented with the purpose of reduction of housing costs for young students and economic support for the senior to prevent isolation and help themselves. Nonetheless, the program has not being activated and the research about it has not progressed well. Therefore, this study as a basic research of the program aims to analyze and evaluate the program in progress in district offices to push it forward. This study was undertaken on documentary research and interviews, which analyzed advanced researches and open materials from the websites of district offices. The interviews were conducted in 4 gu-district offices (Nowon-gu, Gwangjin-gu, Seodaemun-gu, and Seongdong-gu) and did interviews with officials in charge on July in 2015. The result of this study is as follows. First, the Homeshare is being activated around the university town, which has advantage of housing welfare aspects for young students and social welfare aspects for the senior. Second, the support structures of the Homeshare can be categorized as the gu-districts offices, local resources and different structures funded by the Seoul City. Third, the process of the Homeshare takes 5 steps consisted of advertisement, reception/counseling, matching, contract, follow-up management. Fourth, the matching makes it a rule to match the same gender considering safety. In the case of the participation of the official in charge, it has a advantage of solving problems that can occur when the matching, which can lead to smooth progress. Fifth, joint consultation is divided into the contract among participants and the contract between participants and the gu-district office. Sixth, the follow-up management takes rather passive approaches such as calls once or twice a month and visits when necessary. For the activation of the Homeshare, it is required to improve it through the various methods such as regular visits, satisfaction researches and so on. This study resulted from investigating and analyzing the Homeshare operation system between generations will be considered to be a reference to the underlying management.

• Journal of Advanced Navigation Technology
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• v.17 no.3
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• pp.279-284
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• 2013

Among the phases of flight operations pilots feel much pressure in landing segment. There is a number of factors affecting landing safety while pilots reduce aircraft speeds and make a touchdown and stop completely. If runway length is sufficient for landing, there maybe is no problem. But it is not the case all the time. So it is necessary to confirm whether landing performance is within limits or not. Required landing distance is actual landing distance demonstrated by flight test pilot plus allowances for average airline pilots. FAR(Federal Aviation Regulations) AFM certification is based upon manual landing for dry and wet runway. Other runway conditions are not the certification basis. JAR dictates even contaminated/slippery runway is included by prescribed allowances. Automatic landing is not certification basis, so actual landing distances are provided. In this paper I would like to analyze distance allowances included in each type of runway condition. In addition there is no regulation about allowances for specific runway condition, I would suggest adequate allowances for that case.

• Journal of Korean Traditional Oncology
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• v.26 no.1
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• pp.17-27
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• 2021

Objective: This study aimed to evaluate which information of cancer patients should be collected for the Korean medicine cancer registry in order to assess the efficacy and safety of Korean medicine (KM) treatment and to identify Korean medical prognostic predictors. Methods: A total of fifteen Korean medical specialists completed an online survey questionnaire including items about general characteristics of cancer patients and clinical practice patterns. Results: The four main types of cancer at Korean medical hospitals were breast, lung, stomach, and colorectal cancer. The majority of patients with cancer at Korean medical hospitals were in the advanced or metastatic stage (50.0%). The prominent purposes of KM treatment were to alleviate cancer-related symptoms, reduce the side effects of conventional therapy, and improve quality of life. The major options for treatment were traditional herbal medicine (THM), acupuncture, moxibustion, thermotherapy, pharmacoacupuncture, and meditation, with THM being the most frequently used (35.7%). Almost all Korean medical specialists (93.9%) used syndrome differentiation in clinical practice and identified over half the cancer patients as deficiency syndrome (57.2%). Conclusion: Physicians considered the primary goal of KM treatment for cancer patients to be symptom management since advanced or metastatic stage patients were the majority at Korean medical hospitals. THM were the most common treatment option and syndrome differentiation was used by almost all physicians. Further research is needed to monitor and ensure optimal KM treatment for patients with cancer.