• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.6
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• pp.153-158
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• 2017

Reducer is a device to transmit and change torque and speed from drive shaft to driven shaft with excellent transmission efficiency, and it is widely used in many areas today. Reduction gear consists of two axes, gear, bearing supporting axes, and housing. The simplest method to transmit rotation or power to multiple axes is to attach circular plates to two axes and contact each other. However, in this case, if increasing number of rotations or if contact pressure is small, because of slipping, it cannot transmit power. For problems for the current reducer case, it is heavy and its assembling and repair is difficult. In addition, there are few studies about manufacturing and performance testing of worm gear reducer, causing lack of the foundation to improve the product competition and the performance.

• Journal of Practical Engineering Education
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• v.8 no.2
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• pp.75-81
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• 2016

This research proposes to design a flipped classroom with strategic questioning to enhance engineering student's creative problem-solving competency on the basis of the subject knowledge. By applying the designed flipped classroom to both of college and dual system engineering courses during one semester, this study explores to find the meaning and effects of the flipped learning method. The case study analyzed the influences of the flipped learning with the use of strategic questioning on student's problem-solving performance, and also investigated student satisfaction and evaluation of the learning in order to draw out the factors to consider further in the instructional design.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.1
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• pp.49-55
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• 2019

This study proposes a robust control of a fin position servo system using the H-infinity loop-shaping method. The fin position control system has a proportional (P) position controller and a proportional-integral (PI) controller. In this work, the position control loop requires a wide bandwidth. No current control loop exists due to the compact design of the system. Hence, the controller parameters are difficult to determine using the traditional cascade design method. The $H_{\infty}$ controller design method is used to design the controller's gain to achieve good performance and robustness. First, the transfer function of the system, which can be divided into tunable and fixed parts, is derived. The tunable part includes the position P controller and speed PI controller. The fixed part includes the rest of the system. Second, the optimized controller parameters are calculated using Matlab $H_{\infty}$ controller design program. Finally, the system with optimized controller is tested by simulation and experiment. The control performance is satisfactory, and the $H_{\infty}$ controller design method is proven to be valid.

• Journal of Korea Multimedia Society
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• v.22 no.9
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• pp.1036-1045
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• 2019

Relational databases have a notion of normalization, in which the model for storing data is standardized according to the organization's business processes or data operations. However, the graph database is relatively early in this standardization and has a high degree of freedom in modeling. Therefore various models can be created with the same data, depending on the database designers. The essences of the graph database are two aspects. First, the graph database allows accessing relationships between the objects semantically. Second, it makes relationships between entities as important as individual data. Thus increasing the degree of freedom in modeling and providing the modeling developers with a more creative system. This paper introduces different graph models with test data. It compares the query performances by the results of response speeds to the query executions per graph model to find out how the efficiency of each model can be maximized.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.86-91
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• 2024

In the field of artistic creation, the iterative development of AI-generated video software has pushed the boundaries of multimedia content creation and provided powerful creative tools for non-professionals. This paper extensively examines two leading AI-generated video software, PIKA Labs and RUNWAY, discussing their functions, performance differences, and application scopes in the video generation domain. Through detailed operational examples, a comparative analysis of their functionalities, as well as the advantages and limitations of each in generating video content, is presented. By comparison, it can be found that PIKA Labs and RUNWAY have excellent performance in stability and creativity. Therefore, the purpose of this study is to comprehensively elucidate the operating mechanisms of these two AI software, in order to intuitively demonstrate the advantages of each software. Simultaneously, this study provides valuable references for professionals and creators in the video production field, assisting them in selecting the most suitable tools for different scenarios, thereby advancing the application and development of AI-generated video software in multimedia content creation.

• ETRI Journal
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• v.36 no.5
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• pp.696-703
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• 2014

In this paper, we present a walking guidance system for the visually impaired for use at subway stations. This system, which is based on environmental knowledge, automatically detects and recognizes both exit numbers and arrow signs from natural outdoor scenes. The visually impaired can, therefore, utilize the system to find their own way (for example, using exit numbers and the directions provided) through a subway station. The proposed walking guidance system consists mainly of three stages: (a) sign detection using the MCT-based AdaBoost technique, (b) sign recognition using support vector machines and hidden Markov models, and (c) three verification techniques to discriminate between signs and non-signs. The experimental results indicate that our sign recognition system has a high performance with a detection rate of 98%, a recognition rate of 99.5%, and a false-positive error rate of 0.152.

• Current Photovoltaic Research
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• v.8 no.3
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• pp.79-85
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• 2020

The growing demand for new energy infrastructure has often been encountered with the difficulties of siting in power plants and electric transmission lines. Siting such large-scale and complex facilities produces so many-sided issues that it is highly necessary to develop an approach to resolving the related problems and conflicts. This paper introduces how the stakeholders have handled the issues and resolved conflicts with residents opposed the construction of 765 kV transmission line. The solar photovoltaic power generation, called "Hee-Mang Sunlight Power project", is used for persuading residents to agree with constructing high-voltage transmission line and sharing benefits. It is considered how the project performance such as generation output and resident's profits is and proposed what the project should be revised and supplement. The project is shown that the intractable spiting in energy systems can be smartly resolved with cost-effective institutional solutions instead of relatively expensive technical ones.

• Journal of international Conference on Electrical Machines and Systems
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• v.3 no.4
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• pp.487-490
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• 2014

The conventional motor-driven MCCB (molded-case circuit breaker) is not only large in size, but also inefficient in performance. To solve these problems, this paper suggests SPMA (separate permanent-magnet actuator), a novel magnetic actuator. In this paper, SPMA is designed for a 225AF MCCB and compared to a conventional motor-driven MCCB and to an EMFA (electro-magnetic force driving actuator)-type MCCB.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.129-132
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• 2012

Value Engineering(VE) process is going to make a series of improvements for the effective construction project management or optimal proposal to improve quality, performance improvement, cost reduction and customer satisfaction. For making the quality model based on better than the architecture that is required in the VE, such a project promoting creative plan, functionality and constructability reflecting the materials and improved construction methods and building life cycle for reviewing the smooth progress of the construction projects may be necessary for management techniques. This study is to establish a management plan in the educational facilities construction process through education institution's recent orders completed by VE case study.

• Research in Mathematical Education
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• v.8 no.3
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• pp.123-144
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• 2004

There is a tradition of advocating the 'two basics' (basic knowledge and basic skills) in Chinese mathematics education. The direct consequence is that Chinese students are able to produce excellent performance in the international mathematics examinations and outstanding results in the international mathematics competitions. In this article, we will present why and how Chinese teachers teach the 'two basics,' and how combine the pupil's creativity with their 'two basics.' Open ended problem solving is a way to meet the goal. The following topics will be concerned: Culture background; the speed of computation; 'make perfect' ; Efficiency in classroom; Balance between 'two basics' and personal development. In Particular, Chinese mathematics educators pay more attentions to the link between open ended problem solving and the 'two basics' principal.