• Journal of the Semiconductor & Display Technology
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• v.20 no.4
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• pp.38-43
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• 2021

Permanent magnet linear synchronous motor (PMLSM) is suitable for use in cleanroom environments and have advantages such as high speed, high thrust, and high precision. If the stators are arranged in the entire moving path of the mover, there is a problem in that the installation cost increases. To solve this problem, discontinuous armature arrangement PMLSM has been proposed. In this case, the mover receives a greater detent force in the section where the stator is not arranged. When a large detent force occurs, it appears as a ripple component of the thrust during PMLSM operation. If the shape of the stator is changed to reduce the detent force, the characteristics of the back EMF are changed. Therefore, in this paper, the detent force and the harmonic components of back EMF were reduced through multi-purpose shape optimization. To this end, the FEA model was constructed and main effect analysis was performed on the major shape variables affecting each objective function. Then, the optimal shape that minimizes the objective function was derived through the response surface analysis method.

• Journal of Hydrogen and New Energy
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• v.34 no.6
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• pp.758-766
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• 2023

Multi-copter of unmanned aerial vehicle (UAV) was initially developed as strategic technology in the only military field, but it is developing into an industrial field with a wide range of applications in the civil sector based on the development and convergence of aviation technology and information and communication technology. Currently, the degree of utilization of multi-copter is increasing in various industries for the purpose of performing classic tactical missions, logistics transportation, farm management, internet supply, video filming, weather management, life-saving, etc, and active technology development responding to market demand. Existing commercial multi-copter mainly use an electric energy propulsion system consisting of an electric battery and a brushless direct current (BLDC) motor. It is the limitations for usage in the flying time (up to 20 minutes) and payload (less than 20 kg). this study aims to overcome these limitations and expand the commercialization of engine-powered multi-copter of UAV in various industries in the futures.

• Computers and Concrete
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• v.33 no.1
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• pp.91-102
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• 2024

Beam-shaped components commonly rotate along a fixed axis when massive mechanical structures like rotors, jet engine blades, motor turbines, and rotating railway crossings perform their functions. For these structures to be useful in real life, their mechanical behavior is essential. Therefore, this is the first article to use the modified shear deformation theory type hyperbolic sine functions theory and the FEM to study the static bending response of rotating functionally graded GPL-reinforced composite (FG-GPLRC) beams with initial geometrical deficiencies in thermal media. Graphene platelets (GPLs) in three different configurations are woven into the beam's composition to increase its strength. By comparing the numerical results with those of previously published studies, we can assess the robustness of the theory and mechanical model employed in this study. Parameter studies are performed to determine the effect of various geometric and physical variables, such as rotation speed and temperature, on the bending reactions of structures.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.3
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• pp.593-601
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• 2017

With the rapid industrial development and national economic advance since 1970, the national income of Korea has sharply increased. As a result, issues regarding city expansion, urban concentration, increase in the number of registered motor vehicles, and increase in traffic have caused transportation issues such as traffic congestion and problems with parking. Especially, enforcement ordinances and rules have been established on installation and management of parking lots to solve problems with parking which are raised as social problems such as conflict with neighbors but the flexible calculation of legal parking space has the limitations because of the diversity and complex functionality of purposes of facilities. Accordingly, this study attempted to supplement such demerit of the parking space demand forecast method based on the legally required number of parking spaces and average unit requirement in the parking space supply. This study estimated the required number of parking spaces by analyzing existing literature, collecting field research data, and analyzing the factors that have an impact on the parking demand. Also, it compared the required number of parking spaces based on the average unit requirement as well as the required number of parking spaces by the forecast model based on the cumulative number of motor vehicles parked. The result was that the required number of parking space based on average unit requirement was less than the cumulative number of motor vehicles parked by 9.99%. Meanwhile, the required number of parking spaces by the forecast model was more than the cumulative number of motor vehicles parked by 4.37%. Therefore, it is believed that the parking space forecast model is more efficient than the others in estimating there quired parking space. The parking space forecast model of this study consider different environmental factors to enable practical parking demand forecast considering the local characteristics and thus supply the parking space in an efficient way.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3873-3879
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• 2010

Home service robot are not working in the fixed task such as industrial robot, because they are together with human in the same indoor space, but have to do in much more flexible and various environments. Most of them are developed on the base of the wheel-base mobile robot in the same method as a vehicle robot for factory automation. In these days, for holonomic system characteristics, omni-directional wheels are used in the mobile robot. A holonomicrobot, using omni-directional wheels, is capable of driving in any direction. But trajectory control for omni-directional mobile robot is not easy. Especially, azimuth control which sensor uncertainty problem is included is much more difficult. This paper develops trajectory controller of 3-wheels omni-directional mobile robot using fuzzy azimuth estimator. A trajectory controller for an omni-directional mobile robot, which each motor is controlled by an individual PID law to follow the speed command from inverse kinematics, needs a precise sensing data of its azimuth and exact estimation of reference azimuth value. It has imprecision and uncertainty inherent to perception sensors for azimuth. In this paper, they are solved by using fuzzy logic inference which can be used straightforward to perform the control of the mobile robot by means of the fuzzy behavior-based scheme already existent in literature. Finally, the good performance of the developed mobile robot is confirmed through live tests of path control task.

• Journal of Intelligence and Information Systems
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• v.17 no.1
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• pp.37-52
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• 2011

Supply chain management is a strategic thinking which enhances the value of supply chain and adapts more promptly for the changing environment. For the seamless partnership and value creation in supply chains, information and knowledge sharing and proper partner selection criteria must be applied. Thus, the partner selection criteria are critical to maintain product quality and reliability. Each part of a product is supplied by an appropriate supply partner. The criteria for selecting partners are technological capability, quality, price, consistency, etc. In reality, the criteria for partner selection may change according to the characteristics of the components. When the part is a core component, quality factor is the top priority compared to the price. For a standardized component, lower price has a higher priority. Sometimes, unexpected case occurs such as emergency order in which the preference may shift on the top. Thus, SCM partner selection criteria must be determined dynamically according to the characteristics of part and its context. The purpose of this research is to develop an OWL model for the supply chain partnership depending on its context and characteristics of the parts. The uncertainty of variable is tackled through fuzzy logic. The parts with preference of numerical value and context are represented using OWL. Part preference is converted into fuzzy membership function using fuzzy logic. For the ontology reasoning, SWRL (Semantic Web Rule Language) is applied. For the implementation of proposed model, starter motor of an automobile is adopted. After the fuzzy ontology is constructed, the process of selecting preference-based supply partner for each part is presented.

• Science of Emotion and Sensibility
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• v.13 no.2
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• pp.381-390
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• 2010

The automotive seat comfort evaluation was to begin a key aspect in seat design. It depended largely on the basic mechanical aspect such as geometric parameters of seat, choice of suspension system and cushion material used. Until recently, seat comfort evaluation advanced to evaluate subjective sensitivity of human. The external literatures showed in the last decade, there have been very few attempts to establish and document automotive seat comfort evaluation. In 2006 Smith, D. proposed the statistically reliable tool in giving a numeric rating for set comfort and the tool was used in the many country. On the other hands, we, in Korea, had not the reliable tool for the automotive seat comfort evaluation. So that, we studied to develope the questionnaire for seat comfort evaluation based on Smith, D.(2006) and some studies. As a result, we developed 36 contents for the automotive seat comfort evaluation with the help of professional in Korean automotive industry. Here, 36 contents were identified as the dimensions that represent the human sensitivity and psychological feeling on comfortable seat. Also, we derived the priorities for the 36 contents by using analytic hierarchy process (AHP), based on the judgments of 30 experts and drivers. This study will help the designers and developers clarify the conceptual and abstract aspect of the design evaluation by proposing a more systematic and process-oriented method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.5
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• pp.563-569
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• 2018

This paper is on the implementation of a system for automatically monitoring window farm hydroponics based on Arduino (utilizing Arduino's open source code) emerging as the icon of the Fourth Industrial Revolution. A window farm, which means window-type hydroponics, is offered as an alternative to fulfill the desires of people who want to grow plants aside from the busy daily life in the city. The system proposed in this paper was developed to automatically monitor a window farm hydroponics cultivation environment using the Arduino UNO board, a four-charmel motor shield, temperature and humidity sensors, illumination sensors, and a real-time clock module. Modules for hydroponics have been developed in various forms, but power consumption is high because most of them use general power and motors. Since it is not a system that is monitored automatically, there is a disadvantage in that an administrator always has to manage its operational state. The system is equipped with a water supply that is most suitable for a plant growth environment by utilizing temperature, humidity, and light sensors, which function as Internet of Things sensors. In addition, the real-time clock module can be used to provide a more appropriate water supply. The system was implemented with sketch code in a Linux environment using Raspberry Pi 3 and Arduino UNO.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.8
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• pp.5476-5484
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• 2015

The purpose of this study was to verify the clinical usefulness of the virtual reality rehabilitation system which Academic-Industrial cooperation develop through clinical experiment for recovering the functional abilities in stroke. For this purpose, 24 Stroke(hemorrhage13, infarction11)participated in a clinical experiment. They were randomly assigned to the virtual reality rehabilitation system group(n=13) and conventional rehabilitation training(Activities of daily living, cognition training, motor control) group(n=11). All participant were evaluated with three standardized assessment tools(Functional Independent Measure; FIM, Mini-Mental State Examination for Korean; MMSE-K, Self-esteem scale) before and after the planned intervention sessions. All participant were intensively carried out for 8weeks, 3times a week. The results were as follows. The experimental group showed significant improvements for Activities of daily living, basic cognitive abilities and self-esteem related with life satisfaction after the interventions(p<.05). There were no significant differences between two groups for all assessment tool after interventions. Because of this experimental results, the virtual reality rehabilitation system showed the clinical utility for recovering the function in stroke. Further studies are needed to verify the clinical usefulness on the improvement of various functions in brain injury and dementia.

• Journal of Labour Economics
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• v.27 no.1
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• pp.27-53
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• 2004

This paper analyzes the two cases of labor disputes (Hyundai Motor in 1998 and Power Generation Companies in 2002) in the period of restructuring, by applying the behavioral theory of labor negotiations as a comparative framework. The paper compares th backgrounds of the labor disputes, core issues, bargaining processes, and evolutionary patterns and consequences of the labor disputes at the two cases. The common features, found in the two dispute cases, are strong mistrust and exclusive bargaining attitude between labor unions and management, little feasibility of contract zone in bargaining proposals by the two parties, heteronomous dispute resolution by the intervention of the government, and the lack of learning effect gained from the experience of labor disputes. This comparative case study identifies that the confrontational labor-management relations at the firm level is re-produced by a regressive process of the following circulation: labor-management distrust $\rightarrow$ interest conflict in bargaining demand $\rightarrow$ exclusive bargaining attitude $\rightarrow$ the experience of antagonistic dispute $\rightarrow$ deepened distrust. In conclusion, four parties-labor unions, management, the government, and public press - are required to make much effort to replace the vicious circle of labor-management confrontation by a virtueous cycle of labor-management cooperation.