• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.32-39
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• 2017

Recently, usage of mobile cloud services has been increasing. In particular, beyond the constraints of a single cloud computing service, studies on the multi-cloud have been actively pursued. A user must authenticate multiple cloud service providers to use additional cloud services in a multi-cloud. In previous studies, an authentication method using single sign-on (SSO) was not available in all cloud services. Cloud services will not be available when the SSO server is not available due to malicious attacks, because all authentication is done via the SSO server. Additionally, using a broker, there is a vulnerability that can expose authentication information for the service provider to a user who did not sign up. In this paper, we propose a secure user authentication protocol using biometric authentication that does not expose user information when using additional cloud services. The proposed protocol can use a single biometric authentication for multi-cloud services without storing authentication information in each cloud service. In terms of key stability (to ensure stability through the key agreement process and the key area), by disabling various attack methods, such as man-in-the-middle attacks and replay attacks, we provide secure mobile cloud services.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.7
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• pp.434-441
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• 2016

Friction Stir Welding (FSW) is a solid-state joining process involving the frictional heat between the materials and tools. The amount of heat conducted into the workpiece determines the quality of the welded zone. Excessive heat input is the cause of oxides and porosity defects, and insufficient heat input can cause problems, such as tunnel defects. Therefore, analyzing the temperature history and distribution at the center of the Friction Stir Welded zone is very important. In this study, the temperature distribution of the friction stir welding region of an AZ61 magnesium alloy was investigated. To achieve this goal, the temperature and metal flow was predicted using the finite element method. In FE analysis, the welding tool was simplified and the friction condition was optimized. Moreover, the temperature measuring test at the center of the welding region was performed to verify the FE results. In this study, the tool rotation speed was a more dominant factor than the welding speed. In addition, the predicted temperature at the center of the welding region showed good agreement with the measurement results within the error range of 5.4% - 7.7%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.153-161
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• 2016

Urban design claiming the notion of 'Sustainability', which inevitably includes ecological complexity, is normally geared towards the reflection of environmentally-friendly technical guidelines in the existing planning process. Although physical planning should be combined with economic, social, cultural, environmental issues, and policies, it is conducted conventionally as the sum of the closed sectoral approaches of planning. To overcome this limit, Design Charrette was invented for sustainable urban design or community design, which should consider the complexity of diverse issues. This design process unveils complicated and divergent problems and a variety of stakeholders participate in the integrated design simultaneously and cooperatively. Because Design Charrette must also be a process of agreement, it is used for sustainable community design. The aim of this study was to introduce Design Charrette as an alternative of Korean sustainable urban design, which is regarded as 'making guidelines related to green principles'. For such a purposes, the definition and differentiation of Design Charrette will be explained with an analysis of the introduction background, benefit and procedure. The contents, system and process of Design Charrette will be analyzed through case studies in Canada, where this method of design is widespread. In the last part, the implementation system (the comprehensive system of organization / content and direction of planning / process and output) will be deduced after concentrated analysis of one respected case, 'Sensitive Urban Infill Charrette' of the City of Surrey. This implementation system will be a crucial reference to develop Korean Design Charrette.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.483-490
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• 2016

Automobile door latch is a fine design and assembly techniques are required in order to produce them in a small component assembly shape such as a spring, injection products, a small-sized motor. The door latch is fixed to not open the door of the car plays an important role it has a direct impact on the driver's safety. In this study, during trimming of the terminals of the connector main components of the car door latch, reduce rollover and conducted a research to find a suitable effective shear surface. Using the Taguchi method with orthogonal array of Finite Element Analysis and optimal Design of Experiments were set up parameters for the shear surface quality of the car door latch connector terminals. The design parameters used in the analysis is the clearance, the radius, and the blank holding force, the material of the connector terminal is a C2600. Trimming process optimum conditions suggested by the analysis has been verified by experiments, the shear surface shape and dimensions of a final product in good agreement with forming analysis results.Taguchi method from the above results in the optimization for the final rollover and effective shear surface improved for a vehicle door latch to the connector terminal can be seen that the applicable and useful for a variety of metal forming processes other than the trimming process is determined to be applicable.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.543-550
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• 2018

The rapid growth of IoT technology induced by the fourth industrial revolution has resulted in research into various types of wireless sensors, and applications based on this technology are prevalent in many areas. However, among the various sites where this technology is used, railway bridges and tunnels with lengths of tens of kilometers have problems with data acquisition, due to the signal noise induced by the long distance measurement and EMI induced by the high voltage power feeding system, when conventional electric sensors are used. To overcome these problems, many studies on fiber optic sensors have been conducted as a substitute for the conventional electric sensors. However, restrictions on the types of fiber optic sensors have limited their application in railways. For this reason, a hybrid measurement system with IoT based wireless data communication, in which both electric and fiber optic sensors can be applied simultaneously, has been developed. In this study, in order to evaluate the applicability of the hybrid measurement system developed in the previous study, a real-time test for 4 types of measurement environments, which reflect possible railway sites, is performed. As a result, it was confirmed that the signals from both the electric and fiber optic sensors, which were acquired at a remote area in real-time, showed good agreement with each other and that this measurement system has the potential to handle sensors with a sampling rate of 2.5 kHz. In the future, it is expected that the IoT-based hybrid measurement system will contribute to the improvement of structural safety by enabling real-time structural health monitoring when applied to various measurement sites.

• Journal of Korea Port Economic Association
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• v.31 no.1
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• pp.15-36
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• 2015

The purpose of this paper is "A Study on the Establishment of Distribution and Logistics System in the unified Korea". The main conclusion of this paper are as follows : North and South Korea shall conjunctionally foster the exchange and cooperation area and operate the joint pilot project to combine distribution and logistics system. To solve the problems of the maritime affairs, Fisheries, and international logistics, the cooperative agreement between North and South Korea will be needed to protect and develop of shipping, aviation and shipbuilding industry. Unification of two Koreas must be prepared as stage by stage ; ${\cdot}$Stage1(preparation period) : initiation of peace area. ${\cdot}$Stage2(development period) : forming the exchange and cooperation area ${\cdot}$Stage3(settlement period) : establishing peace belt on border area. After the unification, two Koreas must plan and undertake the construction of the distribution and logistics infrastructures, establishment of SCM system through Network and the connection to China through railway and road Network.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.745-752
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• 2020

The purpose of this study is to analyze the development progress of Pacific Park (formerly Atlantic Yard) in Brooklyn, New York City. Along with the Hudson Yards Development in Manhattan, Pacific Park is one of New York City's leading large-scale urban development projects using space right above an existing railway and has attracted worldwide attention. With the resurgence of large-scale development, its advanced form has received social attention. In particular, the development was evaluated as an exemplary development using the Community Benefits Agreement, which benefits local residents. Unfortunately, due to various difficulties, the development has been struggling from delays and changes away from the early stages, which have also caused social concerns and criticism. In this regard, this study examines the development through the process and the public sector's responses to the risk-inducing factors and reactions. The theoretical background of the US urban redevelopment is examined, and the specific changes and major contents of the project are analyzed. The following implications were drawn based on changes and responses in the development process: 1) securing the flexibility and mandatoryness of developers, 2) comprehensive control of the development site, 3) communication with and responding to the public, 4) securing additional financial resources, and 5) verification of new technologies.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.658-663
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• 2018

Current measuring methods for air quality are based on ground measurement networks and satellite data. New methods of collecting evidence with advanced sensors are needed because current methods have limitations in collecting evidence for the illegal emission of air pollutants at narrow areas or specific sites. This study analyzed the possibility of using an ultraviolet hyperspectral sensor to measure the concentration of nitrogen dioxide and sulfur dioxide. Two types of spectra were used: simulated spectra for gases with various concentrations using a radiative transfer model and observed spectra for each gas for a concentration. To understand the possibility of using a hyperspectral sensor, the differences between the simulated spectra and the observed spectra were analyzed, and the variation of simulated spectra were then analyzed according to the concentration. The results showed good agreement between observed spectra and simulated spectra. In addition, the absorption depth at specific wavelengths in the simulated spectra had a very strong correlation with the gas concentration. The gas concentration could be estimated using the hyperspectral sensor. In the future, validation would be needed to estimate the gas concentration through observations of various concentrations of gases using a hyperspectral sensor.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.209-214
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• 2017

The purpose of this study is to identify the factors that led greenhouse grape farms to delay their heating periods after the coming into force of the Korea-Chile Free Trade Agreement (FTA). Panel data on the cropping (system) changes from 2004 through 2016 were used for the analysis. According to the panel logistic model, the estimated coefficient of the cultivation area was 0.0002, which was statistically significant at the 10% significance level, the estimated coefficient of grape imports was 1.4258, which was statistically significant at the 1% significance level, and the estimated coefficient of the regional dummy was 0.808, which was statistically significant at the 5% significance level. The results indicated that the use of wider cultivation areas, increase in grape imports, and colder climate(in the mid-northern part of Korea) increased the likelihood of delayed heating. The Korean government is offering direct payment programs and business closure support to the greenhouse grape farmers. While these actions can relieve the damage caused by the increase in grape imports, they will not provide the ultimate solution. Various support measures are needed, such as renewing the varieties to meet the changing demand of grape consumers, providing agricultural materials to reduce the heating expenses, and modernizing greenhouse facilities to improve the energy efficiency and reduce the costs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.2
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• pp.202-209
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• 2005

This study concerns the performance of boiling heat transfer in inclined thermosyphons with internal grooves. A study was carried out with the performance of the heat transfer of the inclined thermosyphon having 60 internal grooves in which boiling and condensation occur. A plain thermosyphon having the same inner and outer diameter as the grooved thermosyphon is also tested for comparison. Distilled water, methanol and ethanol have been used as the working fluid. The inclination angle, three working fluids, heat flux and the boiling heat transfer coefficient at the evaporator zone are estimated from the experimental results. The experimental results have been assessed and compared with existing correlations. Imura's and Kusuda's correlation for boiling showed in good agreement with experimental results within ${\pm}20%$ in plain thermosyphon. The high heat transfer coefficient was found between $25^{\circ}$ and $30^{\circ}$ of inclination angle for water and between $20^{\circ}$ and $25^{\circ}$ for methanol and ethanol. The relatively high rates of heat transfer have been achieved in the thermosyphon with internal micro grooves.