• Journal of Communications and Networks
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• v.18 no.6
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• pp.913-925
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• 2016

In-band wireless full-duplex is a promising technology that enables a wireless node to transmit and receive at the same time on the same frequency band. Due to the complexity of self-interference cancellation techniques, only base stations (BSs) are expected to be full-duplex capable while user terminals remain as legacy half-duplex nodes in the near future. In this case, two different nodes share a single subchannel, one for uplink and the other for downlink, which causes inter-node interference between them. In this paper, we investigate the joint problem of subchannel assignment and power allocation in a single-cell full-duplex orthogonal frequency division multiple access (OFDMA) network considering the inter-node interference. Specifically, we consider two different scenarios: i) The BS knows full channel state information (CSI), and ii) the BS obtains limited CSI through channel feedbacks from nodes. In the full CSI scenario, we design sequential resource allocation algorithms which assign subchannels first to uplink nodes and then to downlink nodes or vice versa. In the limited CSI scenario, we identify the overhead for channel measurement and feedback in full-duplex networks. Then we propose a novel resource allocation scheme where downlink nodes estimate inter-node interference with low complexity. Through simulation, we evaluate our approaches for full and limited CSIs under various scenarios and identify full-duplex gains in various practical scenarios.

• Journal of the Korea Convergence Society
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• v.6 no.5
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• pp.303-314
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• 2015

In This paper we study the interrelationship between firm's strategies, MCS (Management Control System), and financial and non-financial performance. And also the objective of this study is to advance the understanding of mediating effect of management accountant on these relationships. This is a suggestion on the study of contemporary settings as little contingency work was carried out on balanced scorecard, target costing, life cycle costing, which come under the broad array of non-financial performance indicators. The result of this study finds that the higher the unpredictability of the business, the more necessary it is to secure a controller within the business. This strongly implies that the controllers must be the main subject of continued growth as they perform an active role within the overall management control process of performance indicator development, performance measurement, feedback, and reward, starting from the very beginning stages of the strategy development within the business.

• Archives of design research
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• v.14 no.1
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• pp.27-34
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• 2001

In order to design the products that impression or emotional taste influence the purchase, feedback is necessary as useful data for better idea sketches through users emotional evaluation in early stage of design process. On the other hand, it was required to make judgments individually in previous image evaluations for emotional evaluations such as semantic differential method (SD method) that objects have been considered as classified tendency. However those SD methods are not enough to reflect flexible human capability with similarity judgment in object perceptual process. Therefore, this study proposes a classification of stimulus based on intuitive judgment and a hierarchical image evaluation method based on analysis of hierarchical process and fuzzy integration. The evaluation will be conducted through the order of process, intuitive classification of objective stimulus and items, definition of representatives in each class. Evaluation for each image of the stimulus, calculation of prior raking based on fuzzy integration. The evaluation supportive software is developed to conduct this evaluation process under interactive environments.

• Progress in Superconductivity
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• v.8 no.2
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• pp.164-168
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• 2007

We developed a SQUID magnetometer based on Double Relaxation Oscillation SQUID(DROS) for measuring magnetocardiography(MCG). Since DROS provides a 10 times larger flux-to-voltage transfer coefficient than the conventional DC-SQUID, simple flux-locked loop electronics could be used for SQUID operation. Especially, we adopted an external feedback to eliminate the magnetic coupling with adjacent channels. When the DROS magnetometer was operated inside a magnetically shielded room, average magnetic field noise was about 5 $fT/^{\surd}Hz$ at 100 Hz. Using the DROS magnetometer, we constructed a multichannel MCG system. The system consisted of 61 magnetometers are arranged in a hexagonal structure and measures a vertical magnetic-field component to the chest surface. The distance between adjacent channels is 26 mm and the magnetometers cover a circular area with a diameter of 208 mm. We recorded the MCG signals with this system and confirmed the magnetic field distribution and the myocardinal current distribution.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.289-290
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• 2006

In general, atomic force microscope (AFM) used for metrological purpose has measuring range less than a few hundred micrometers. We design and fabricate an AFM with long measuring range of $200mm{\times}200mm$ in X and Y axes. The whole stage system is composed of surface plate, global stage, microstage. By combining global stage and microstage, the fine and long movement can be provided. We measure the position of the stage and angular motions of the stage by laser interferometer. A piezoresistive type cantilever is used for compact and long term stability and a flexure structure with PZT and capacitive sensor is used for Z axis feedback control. Since the system is composed of various actuators and sensors, a real time control program is required for the implementation of AFM. Therefore, in this work, we designed a multi-axis control program using a FPGA module, which has various functions such as interferometer signal converting, PID control and data acquisition with triggering. The control program achieves a loop rate more than 500 kHz and will be applied for the measurement of grating pitch and step height.

• Journal of Sensor Science and Technology
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• v.4 no.3
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• pp.9-14
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• 1995

For the development of liquid density measuring sensor using the natural frequency of a pipe, its principle and construction method were described. The stainless steel pipe, which has length of 32 cm, inside diameter of 2.3 cm and outside diameter of 2.5 cm, was used for the sensor. The exciting coil and the photo sensor were used to excite and to pick-up it, and the feedback circuit was designed to continue its vibrating. The natural frequency was consistent with the result of the spectrum analysis. It had a linearity of 0.0027 % and a sensitivity of 0.032 % in liquid density range from $0.8\;g/cm^{3}$ to $1.4\;g/cm^{3}$ and its frequency variation ratio was 0.024 $%/^{\circ}C$ in temperature range from $10^{\circ}C$ to $35^{\circ}C$.

• Journal of Digital Contents Society
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• v.19 no.7
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• pp.1225-1235
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• 2018

In this study, as a part of practical and customized smart contents development planning research related to smart fitness contents associated with smart wear that can monitor physical activity, we investigated the potential needs for smart fitness contents through research. As a result, the potential needs for smart fitness contents is 'accessibility to use', 'inducement of interest', 'diverse story line' were derived at the stage of 'before exercise', 'Real - time voice coaching', 'accurate exercise posture monitoring', and 'personalized exercise prescription' were derived at the stage of 'during exercise'. At the stage of 'after exercise', 'substantial reward system', 'grading system', 'body figure change monitoring' and 'everyday life monitoring' were derived. At the stage of 'connection to the next exercise', 'triggering exercise motivation', 'high sustainability' wear derived.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.47-53
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• 2013

Nowadays, Advanced country have devised a plan energy-saving through lighting effectiveness and increasing performance of lighting control system. If it uses the LED as a source of light then conserve electricity by 50%. This paper implement LEMS(Lighting Energy Management System) that applicate and Smart Dimmer and Smart Switch that control the digital LED light, support wired-wireless communication using USN(Ubiquitous Sensor Network). This system of validity and reliability control special purpose lamp including indoor and outdoor lighting and landscape lighting effectively. It minimize the use of indoor and outdoor lighting energy by USN remote integral control function of Digital System Lighting of LED and increase effectiveness of energy and is a collaborative system that can feedback the use of electricity by measurement itself through Web and Switch.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.9 no.4
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• pp.506-514
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• 1998

The design and fabrication of X-band(11.7~12 GHz) 2-stage monolithic microwave integrated circuit(MMIC) low noise amplifier (LNA) for active antenna are presented using $0.15{\mu}m\times140{\mu}m$ AlGaAs/InGaAs/GaAs pseudomorphic high electron mobility transistor (P-HEMT). In each stage of the LNA, a series feedback by using a source inductor is used for both input matching and good stability. The measurement results are achieved as an input return loss under -17 dB, an output return loss under -15dB, a noise figure of 1.3dB, and a gain of 17 dB at X-band. This results almost concur with a design results except noise figure(NF). The chip size of the MMIC LNA is $1.43\times1.27$.

• Journal of Korean Institute of Industrial Engineers
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• v.43 no.2
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• pp.100-111
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• 2017

Evaluating the performance of R&D Activity is complicated because it is hard to quantify the R&D results unlike the traditional manufacturing or service industries. Recently, to overcome this, process-focused evaluation methods applying the philosophy of quality into R&D environment have been introduced. However, these quality activities are mainly conducted without feedback system after the evaluation work is done. The aim of this study is to present a R&D quality diagnosis framework to obtain the improvement opportunities from R&D process perspective. The research is designed as follows : First, R&D standard process and R&D quality elements are derived from a literature review. Second, the diagnosis objects are obtained by investigating the R&D quality elements at each R&D steps. Third, a two-dimensional diagnosis model, which enables the objective measurement of the 'system compatibility' and 'accomplish level', is presented. The proposed method can provide an effective way to find opportunities for efficient quality improvement of R&D process.