• Journal of Periodontal and Implant Science
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• v.28 no.4
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• pp.823-828
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• 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.

• Current Photovoltaic Research
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• v.5 no.1
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• pp.28-32
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• 2017

In this paper, (Ga,Al):ZnO layers were deposited by sputtering to evaluate the device performance according to the thickness of the layer. As the thickness increased, low transmittance was observed, but the electrical resistance was improved. On the other hand, the highest efficiency was recorded at 400 nm device than a 500 nm of it. Therefore, since the critical thickness exists, it is necessary to set an adequate TCO layer thickness in consideration of the characteristics of the underlying film and the device.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.2
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• pp.63-66
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• 2017

This research was about shielded trench gate power MOSFET for low voltage and high speed. We used T-CAD tool and carried out process and device simulation for exracting design and process parameters. The exracted parameters was used to design shieled and conventional trench gate power MOSFET. And The electrical characteristics of shieled and conventional trench gate power MOSFET were compared and analyzed for their power device applications. As a result of analyzing electrical characteristics, the recorded breakdown voltages of both devices were around 120 V. The electric distributions of shielded and conventional trench gate power MOSFET was different. But due to the low voltage level, the breakdown voltage was almost same. And the other hand, the threshold voltage characteristics of shielded trench gate power MOSFET was superior to convention trench gate power MOSFET. In terms of on resistance characteristics, we obtained optimal oxied thickness of $3{\mu}m$.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.77.5-77
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• 2002

A mechanical device was developed for assisting the grasping function of a person whose fingers suffered cervical injury and thus are unable to grasp. This device is composed of a mechanical glove put on the user's hand and a muscle sensor to measure the activity of his or her muscle. The mechanical glove consists of a finger frame, a base and an air cylinder mounted on the base. With the kinematics carefully designed, the finger frame can achieve the grasping motion under the actuation of the air cylinder. For controlling this motion, an innovative sensor was developed to detect the user's motion intention. The sensor measures the change of the muscle stiffness...

• Journal of Magnetics
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• v.18 no.2
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• pp.183-187
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• 2013

Two concurrent signals of the pulse wave measured from both hands' radial artery in un-pressurization condition using the prototype model of two clip-type pulsimeters with a permanent magnet and Hall device are investigated. The phase differences of two pulse waves from 22 subjects have some distinct points according to the handedness. Thus, the propagation of the pulse wave calculated from phase difference is both fast and slow to each other. It is confirmed that this phenomenon comes from the difference of blood vessel hardness between right- and left-hand of each subject rather than a quantity of muscle.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.1 s.232
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• pp.81-87
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• 2005

A fracture of hand held device, such as radio, TV and CD-RW drive, mainly occurs due to drop situation. For CD-RW drive, the need of high reading/writing speed in conjunction with low price accelerates the fracture of the device. Computer simulation can reduce the period of development and enhance impact characteristic of device. In this study, the detailed finite element model of CD-RW drive was developed to predict the damage under drop conditions. Material property for shock absorbing damper was obtained from tensile test of raw material. A MOONEY-RIVLIN type rubber in LS-DYNA was used as the material model of damper. To assess the reliability of the developed model, drop test at 200G-2msec and 150G-10msec condition was conducted and acceleration at pick-up was compared.

• ETRI Journal
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• v.16 no.4
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• pp.1-11
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• 1995

A GaAs power metal semiconductor field effect transistor (MESFET) operating at a voltage as low as 3.3V has been developed with the best performance for digital handheld phone. The device has been fabricated on an epitaxial layer with a low-high doped structure grown by molecular beam epitaxy. The MESFET, fabricated using $0.8{\mu}m$ design rule, showed a maximum drain current density of 330 mA/mm at $V_{gs}$ =0.5V and a gate-to-drain breakdown volt-age of 28 V. The MESFET tested at a 3.3 V drain bias and a 900 MHz operation frequency displayed an output power of 32.5-dBm and a power added efficiency of 68%. The associate power gain at 20 dBm input power and the linear gain were 12.5dB and 16.5dB, respectively. Two tone testing measured at 900.00MHz and 900.03MHz showed that a third-order intercept point is 49.5 dBm. The power MESFET developed in this work is expected to be useful as a power amplifying device for digital hand-held phone because the high linear gain can deliver a high power added efficiency in the linear operation region of output power and the high third-order intercept point can reduce the third-order intermodulation.

• Journal of Korea Game Society
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• v.15 no.1
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• pp.27-34
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• 2015

This paper proposes a user interface for enhancing immersiveness and usability by combining hologram and haptic device with common Leap Motion. While Leap Motion delivers physical motion of user hand to control virtual environment, it is limited to handle virtual hands on screen and interact with virtual environment in one way. In our system, hologram is coupled with Leap Motion to improve user immersiveness by arranging real and virtual hands in the same place. Moreover, we provide a interaction prototype of sense by designing a haptic device to convey touch sense in virtual environment to user's hand.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.4
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• pp.87-90
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• 2008

This research is to study and analyze our country's management of disasters, the present condition of cultural heritages bases on the examples of temples, and Japan's safety management prevention of buddhist temple. As a result, this research aims to how to improve the temple fire prevention system. To improve the anti-fire system of temples, it is important to make new laws about fire lose to minimize cultural property lose. Secondly, to protect self-contained type fire alarm device, with aerosol type hand propelled fire extinguishers to prevent fire lose. Lastly, construction work of electric engineer is necessary to prevent temple fire loses.

• International Journal of Internet, Broadcasting and Communication
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• v.9 no.4
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• pp.59-66
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• 2017

Cloud computing has evolved into a core computing infrastructure for the internet that encompasses content, as well as communications, applications and commerce. By providing powerful computing and communications capabilities in the palm of the hand everywhere with a variety of smart devices, mobile applications such as virtual reality, sensing and navigation have emerged and radically changed the patterns people live. The data that is generated is getting bigger. Cloud computing, on the other hand, has problems with system load and speed due to the collection, processing and control of remote data. To solve this problem, fog computing has been proposed in which data is collected and processed at an edge. In this paper, we propose a system that dynamically selects a fog server that acts as a cloud in the edge. It serves as a mediator in the cloud, and provides information on the services and systems belonging to the cloud to the mobile device so that the mobile device can act as a fog. When the role of the fog system is complete, we provide it to the cloud to virtualize the fog. The heterogeneous problem of data of mobile nodes can be solved by using mDBaaS (Mobile DataBase as a Service) and we propose a system design method for this.