• 한국소음진동공학회논문집
• /
• 제13권9호
• /
• pp.663-670
• /
• 2003

As the micro-technologies in the high precision manufacturing processes are developed, the demand for micro actuating device is increasing. But, it is difficult to achieve high resolution and wide operating range simultaneously with the conventional actuating systems which are contacting and type of dual servo system. So, the contact-free surface actuators whose movers are suspended or levitated were proposed. These systems can be applied to high precision stages and alignment apparatuses. The suspended mover can be assumed to be rigid body, but the mover is a structure in this study, therefore the vibration caused during the operating process has a serious adverse effect on the performance and it is very important to identify the vibrational characteristics. In this paper, a contact-free surface actuator is modeled in finite element method and updated by using the experimental modal data. Finally, the static and dynamic characteristics of the finite element model are predicted and then discussed.

• 한국정밀공학회지
• /
• 제23권5호
• /
• pp.85-92
• /
• 2006

Recently in the field of precision positioning device, the contact-free stages are gaining focuses with their outstanding performances by eliminating mechanical frictions. This paper presents the driving algorithm for contact-free linear stage based on switched reluctance principle. The proposed driving algorithm has a similar structure of that of switched reluctance motor but this study has its own originality in terms of reducing the normal farces and force ripple at the same time. The simulation and experiment are executed to verify the proposed algorithm.

• EDISON SW 활용 경진대회 논문집
• /
• 제4회(2015년)
• /
• pp.452-459
• /
• 2015

Thanks to the development of applications, many people are using a smart phone cradle these days. But it has some problems. First of all, it is hard to fix on automobiles. Also, it is vulnerable to external vibration. Recognizing these problems, we decided to improve this device by using FreeCAD and ANSYS. Because FreeCAD is newly invented software, we used another 3D modeling software to cover shortages of tools in FreeCAD. Also, we used famous analysis software 'ANSYS' to analyze bending deformation, modal analysis, and harmonic analysis.

• Asia pacific journal of information systems
• /
• 제33권2호
• /
• pp.318-341
• /
• 2023

Mobile TV refers to the service that provides live broadcasting and video-on-demand content through a mobile device. In addition to the advertisement as the early-stage revenue model, the paid subscription model has emerged as a more sustainable revenue source for mobile TV services. In this study, with the surveys of 450 free mobile TV users, we examine the motivational factors influencing their intention to adopt a paid subscription model. Results show that three extrinsic motivations, price fairness, subjective norm, and mobile TV utilization, are positively associated with free users' paid subscription intention. In contrast, intrinsic motivations, such as hedonic need, spatiotemporal convenience, and self-efficacy, have no significant influence on the intention. We also found that the expected value is positively associated with attitude toward mobile TV service, also positively influencing the paid subscription intention.

• Journal of Biosystems Engineering
• /
• 제41권1호
• /
• pp.21-33
• /
• 2016

Purpose: In order to ensure that vegetable seedlings (with a soil block around their roots) are planted in an upright orientation after metering in a vegetable transplanter, they need to be dropped freely from a certain height. The walk-behind hand-tractor-powered machines do not have sufficient space to drop the seedlings from that height. In the present work, a hopper-type planting device was developed for the walk-behind hand-tractor-powered vegetable transplanter to ensure that the soil block seedlings are planted in an upright orientation. Methods: Various dimensionless terms were developed based on the dimensional analysis approach, and their effect on the planting of soil block seedlings in an upright orientation (planting efficiency) was studied. The optimum design dimensions of the hopper-type planting device were identified by the Taguchi method of optimization. Results: The ratio of the height of free fall to the sliding distance of the seedling on the surface of the hopper had the highest influence on planting efficiency. The planting efficiency was highest for plants with a height $15{\pm}2cm$. The plant handling Froude number, in interaction with the design of the hopper-type planting device, also significantly affected the planting efficiency. Of the hopper design factors, the length of the slide of the seedlings on the surface of the hopper was most important, and induced sufficient velocity and rotation to cause the seedling to fall in an upright orientation. An evaluation of the performance of the planting device under actual field conditions revealed that the planting efficiency of the developed planting device was more than 97.5%. Conclusions: As the seedlings were fed to the metering device manually, an increase in planting rate increased missed plantings. The planting device can be adopted for any vegetable transplanter in which the seedlings are allowed to drop freely from the metering device.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2014년도 추계학술대회
• /
• pp.259-263
• /
• 2014

ICT 분야에서 2014년의 주목할 만한 이슈 중 하나가 "입는 컴퓨터(Wearable Computer)" 즉 "Wearable Device" 시대의 개막이다. 삼성 갤럭시 기어, 구글 글래스, 그리고 애플 워치와 같은 제품들을 웨어러블 디바이스라고 한다. MIT 미디어 랩의 정의에 따르면 웨어러블 디바이스는 신체에 부착하여 컴퓨팅 행위를 할 수 있는 모든 것을 지칭하며 일부 컴퓨팅 기능을 수행할 수 있는 애플리케이션까지 포함하고 있다. 웨어러블 디바이스는 또 하나의 두뇌다. 웨어러블 디바이스가 대중화되면 달라지는 것이 수없이 많아질 것이다. 일단 두 손이 자유로워진다. 내 몸이 24시간 인터넷과 연결되기 때문이다. 단지 스마트폰이나 디바이스를 몸에 붙인다는 수준이 아니라 디바이스가 바로 우리 몸의 외부에 연결되어 있는 두뇌 역할을 하게 될 것이다. 본 논문에서는 이러한 웨어러블 디바이스의 기술 요소를 관련 기업들 별로 분석해 본다.

• Journal of Periodontal and Implant Science
• /
• 제28권4호
• /
• pp.823-828
• /
• 1998

A primary goal of periodontal therapy is the creation of root surfaces that are free of plaque and calculus. It is not yet to be determined whether it is desirable to have a smooth root surface after treatment. It is also not clear what degree of roughness result from different instruments. In the present study various instruments for root surface debridement were evaluated. 20 extracted teeth were utilized, and the teeth were treated with one of the following instrument: Gracey curette, Perio Clean, and piezo ultrasonic device(Setlec, P Max) with general scaler tip, curette-like tip, and diamond tip. 3 dimensional planimetric device(Accura) was used to evaluate the average surface roughness. It was demonstrated hand and power-driven instruments did not have a significant difference in roughness of the root surface following instrumentation. And ultrasonic scaler tip tended to make a most smooth surface than other instruments. The possible reasons of the result were discussed.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1993년도 춘계학술대회 논문집
• /
• pp.257-261
• /
• 1993

This paper presents a design method of turning device for robotic assembly based on the verification of a instability for a base assembly. To derive the instability, first we inference collision free assembly directions by extracting separable directions for the part, and calculate the separability which gives informations as to how the part can be dasily separated. Using the result, we determine the instability evaluated by summing the all separabilites of each component part in base assembly. The proposed method gives a design guidance of turning device by evaluating a degree of the motion istability for the base assembly in flexible manufacturing application. An example is given to illustrate the concepts and procedure of the proposed scheme.

• Archives of Reconstructive Microsurgery
• /
• 제24권1호
• /
• pp.20-23
• /
• 2015

Despite increased utilization of microvascular anastomotic coupler (MAC) devices, the consequences have yet to be fully explored in terms of vascular regeneration. Removal of an exposed venous coupler is described herein, documenting normal circulatory flow through the remodeled site of application. A 25-year-old man who underwent open reduction and rigid fixation elsewhere for traumatic calcaneal fracture ultimately presented with a necrotic postoperative wound. The debrided defect was treated by free thigh perforator flap, incorporating a MAC device. Three months later, the flap remained viable, but the MAC itself was exposed. Structural integrity of the vessel and blood flow were sustained as the device was carefully removed, confirming true vascular remodeling in this example of MAC usage.

• Transactions on Electrical and Electronic Materials
• /
• 제3권4호
• /
• pp.32-35
• /
• 2002

In this work, we test electrode material of TFD (Thin Film Diode) device subject to flexible substrate. Al, that is ductile metal, was proper for flexible electrode to fabricate flexible display. The fabricated devices had symmetric electrode structure on both sides of insulation layer. The electrode was made of ductile Al so as to reduce the mismatch of properties between the electrode and substrate. The TFD device was successfully fabricated applying our own etch-free process. Electrical properties were improved by post-annealing.