• Proceedings of the Korean Vacuum Society Conference
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• 2009.08a
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• pp.123-123
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• 2009

• Proceedings of the Korean Vacuum Society Conference
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• 2009.08a
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• pp.113-113
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• 2009

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.789-794
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• 2000

This study proposes an error analysis for a cubic parallel device. There are many sources of errors in the device. An error analysis is presented based on an error model formed from the relation between the universal joint error of the cubic parallel manipulator and the end effector accuracy. The analysis shows that the method can be used in evaluating the accuracy of a parallel device.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.318-318
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• 2012

A graphene layer is most important materials in resent year to enhance the electrical properties of semiconductor device due to high mobility, flexibility, strong mechanical resistance and transparency[1,2]. The resistance switching memory with the graphene layer have been reported for next generation nonvolatile memory device[3,4]. Also, the graphene layer is able to improve the electrical properties of memory device because of the high mobility and current density. In this study, the resistance switching memory device with metal-oxide nano-particles embedded in polyimide layer on the graphene mono-layer were fabricated. At first, the graphene layer was deposited $SiO_2$/Si substrate by using chemical vapor deposition. Then, a biphenyl-tetracarboxylic dianhydride-phenylene diamine poly-amic-acid was spin coated on the deposited metal layer on the graphene mono-layer. Then the samples were cured at $400^{\circ}C$ for 1 hour in $N_2$ atmosphere after drying at $135^{\circ}C$ for 30 min through rapid thermal annealing. The deposition of aluminum layer with thickness of 200 nm was done by a thermal evaporator. The electrical properties of device were measured at room temperature using an HP4156a precision semiconductor parameter analyzer and an Agilent 81101A pulse generator. We will discuss the switching mechanism of memory device with metal-oxide nano-particles on the graphene mono-layer.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.5
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• pp.673-681
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• 2014

In this paper, a novel low specific on-resistance SOI LDMOS Device with P+P-top layer in the drift region is proposed and investigated using a two dimensional device simulator, MEDICI. The structure is characterized by a heavily-doped $P^+$ region which is connected to the P-top layer in the drift region. The $P^+$ region can modulates the surface electric field profile, increases the drift doping concentration and reduces the sensitivity of the breakdown voltage on the geometry parameters. Compared to the conventional D-RESURF device, a 25.8% decrease in specific on-resistance and a 48.2% increase in figure of merit can be obtained in the novel device. Furthermore, the novel $P^+P$-top device also present cost efficiency due to the fact that the $P^+$ region can be fabricated together with the P-type body contact region without any additional mask.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.10 s.241
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• pp.1119-1129
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• 2005

A new measurement system of wall pressure fluctuations on a rotating machinery, composed of digital recording device, was developed and evaluated. The small-sized digital recording device was attached on the rotating machinery and then was detached for data reduction. In order to obtain the system transfer function of the digital recording system, a dynamic calibration was performed utilizing the signal from a 1/8 inch B&K microphone as input. The time history of the unsteady pressure was then reconstructed from the output of the sensor by using this transfer function. The reconstructed pressure signals showed good agreement with the reference signal in both temporal and spectral sense. This sensor was then used to measure the wall pressure fluctuations on a rotating blade. An array of microphones were installed on the blade in the circumferential and radial directions. Various statistical moments were obtained from the measurement data set. Comparison of these quantities with the existing studies demonstrated satisfactory agreement. These tests give credence to the relevance and reliability of this device for applications in more complicated turbulent rotating machineries.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.4
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• pp.284-288
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• 2013

Power MOSFETs(Metal Oxide Semiconductor Field Effect Transistor) operate as energy control semiconductor switches. In order to reduce energy loss of the device during switch-on state, it is essential to increase its conductance. We have experimental results and explanations on the doping profile dependence of the electrical behavior of the vertical MOSFET. The device is fabricated as $8.25{\mu}m$ cell pitch and $4.25{\mu}m$ gate width. The performances of device with various p base doping concentration are compared at Vth from 1.77 V to 4.13 V. Also the effect of the cell structure on the on-resistance and breakdown voltage of the device are analyzed. The simulation results suggest that the device optimized for various applications can be further optimized at power device.

• Journal of Information Technology Services
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• v.11 no.2
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• pp.339-353
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• 2012

Mobile communication technology is advancing forward to deliver more connected devices and richer content and applications. The number of subscriptions continues to grow along with an explosive increase in the mobile data traffic demand. Thereby, it creates a significant network capacity shortage concerns for mobile network operators. In order to address this problem, it is essential to increase the network capacity at a low additional cost. The device-to-device (D2D) communication based proximity service is believed to have a promising future mobile communication technology that is capable to create new mobile service opportunities and offload traffic to the eNB. In addition, it is also required to develop new mobile communication services and its business models not only to accommodate the increasing mobile traffic demand but also to foster profitability of mobile business service providers such as the network providers, contents providers and platform providers. In this article, we first analyze current mobile business eco-system in the context of CPNT based value chain. Then, propose service development framework and business model creation methodologies for the device-to-device communication based services in the beyond LTE/LTE-Advanced systems.

• Journal of Biosystems Engineering
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• v.26 no.2
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• pp.115-122
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• 2001

An impact-type seed-metering device was developed for the planting of rice-pellets. In this study, new design of pellet-metering device focused on simplicity and precision seeding for the planting of rice-seed pellets. In addition of seed-metering device, several devices were also developed such as seed-guiding device, seed-supplying tube and furrow opener for precision pellet planting. Field test was conducted to estimate the planting performance of the developed metering device. As a cam rotates, the impact bar of the metering device pushes a rice-seed pellet so that the seed can be discharged from the seed-supplying tube in the impact-type seed-metering device. Results of the tests showed that mean seeding spacing was 12cm at the traveling speed of 1.0m/s, corresponding to a target spacing for planting of rice-seed pellets. Also, both miss-seeded rate and damaged-seed rate were less than 2.0%, indicating acceptable levels for the precision planting. The developed mechanism of the impact-type metering device can be directly applied to the design of metering devices for the precision pellet planting of other crops.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.10
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• pp.893-897
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• 2013

Recently the interest on device-to-device (D2D) communication has been increased due to the growing popularization of smart phones and tablet PCs. However, existing device identification mechanisms of D2D communication provide a text-based long list of possible devices, which leads the users to avoid to use D2D techniques. In this paper, we propose a location-based device identification technique for D2D communication. This paper describes the algorithm, analyzes its accuracy using analytical models, and verifies the results using computer simulations. The proposed algorithm is more user-friendly and intuitive way than existing D2D techniques.