• 한국군사과학기술학회지
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• 제24권2호
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• pp.204-210
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• 2021

In this paper, we studied a method of wirelessly checking up the POD for captive flight tests which is performed during the development of guided weapons systems. The wireless power transfer module, the power distribution device, and the battery pack were designed to wirelessly power the captive flight test POD, and the communication device was designed to enable wireless communication between the POD and the check-up device. The communication device was designed to enable WiFi, IR communication, and laser diode communication, so that various communication methods could be tested. Through the performance test, it was confirmed that power was stably supplied to the captive flight test POD, and the wireless communication performance was verified by measuring the delay time and error rate. As a result, by using our system the POD check-up for the captive flight test was performed wirelessly and the data of the captive equipment could be obtained effectively.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권5호
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• pp.1984-2002
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• 2020

With the appearance of wireless spectrum crisis in traditional cellular network, device-to-device (D2D) communication has been regarded as a promising solution to ease heavy traffic burden by enabling precise content delivery among mobile users. However, due to the channel sharing, the interference between D2D and cellular users can affect the transmission rate and narrow the throughput in the network. In this paper, we firstly present a weighted interference minimization cluster formation model involving both social attribute and physical closeness. The weighted-interference, which is evaluated under the susceptible-infected(SI) model, is utilized to gather user in social and physical proximity. Then, we address the cluster formation problem via spectrum clustering with iterative operation. Finally, we propose the stable matching theory algorithm in order to maximize rate oriented to accomplish the one-to-one resource allocation. Numerical results show that our proposed scheme acquires quite well clustering effect and increases the accumulative transmission rate compared with the other two advanced schemes.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.693-696
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• 2002

In this paper, network management system(NMS) was developed using Ethernet network for several devices. Recently, due to the development of the information communication, network has been constructed several place. And management system using network has been studied due to the increment of necessity of remote control for industrial device. Agent board that necessity of NMS, was developed using general micro-controller, it operates like stand-alone network device, supports TCP/IP protocol suite, has the ability to connect to industrial device and communicates each other. Also manager base on MMI was developed, it operates with agent board and supports effective management. To prove this system UPS(uninterruptible power supply) is selected as the example of industrial device. Finally, experimental result verifies the communication between agent board and manager.

• 디지털융복합연구
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• 제13권4호
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• pp.205-210
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• 2015

자동차산업의 발전과 함께 M2M(Machine-to-Machine)통신이 자동차 산업분야에서 많은 관심이 되고 있다. M2M은 기상, 환경, 물류, 국방, 농.축산 등에서 사용하기 시작하여 장비들이 자동으로 상황에 맞추어 통신을 하고 상황에 맞는 동작을 함으로써 운영해가는 시스템이다. 자동차에서도 차량내부 장치 간, 차대 차, 차와 교통시설물, 차와 주변의 환경 등에 적용되고 있다. 그러나 통신시스템의 특성상 전송구간에서 공격자의 공격에 대한 문제가 있으며 자동차의 운행, 제어계통 및 엔진제어 등에 공격자의 공격이 진행되면 안전에 심각한 문제가 발생하게 된다. 따라서 디바이스 간 보안통신에 대한 연구가 활발히 진행되고 있다. 본 논문에서는 차량의 디바이스간 안전한 통신을 위해 해시함수 및 수학적 복잡한 공식을 이용하여 프로토콜을 설계하였으며 프로토콜 정형검증 도구인 Casper/FDR을 이용하여 실험하였으며 제안한 프로토콜이 각종 공격에 안전하게 동작되며 실제 적용할 때 효과적임을 확인하였다.

• 한국인쇄학회지
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• 제18권1호
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• pp.103-112
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• 2000

The color space transformation to link device-dependent color spaces and device-independent color spaces is essential for device characterization and cross-media color reproduction. There are various color conversion methods such as regression, 3D interpolation with LUT(look-up table), and neural network. In the color transformation with these methods, the conversion accuracy is essentially based on the sample data to be exploited for device characterization. In conventional method, color samples are uniformly selected in device-dependent space such as CMY and RGB. However, distribution of these color samples is very non-uniform in device-independent color space such as CIEL*a*b*. Accordingly, the conversion error in device-independent color space is irregular according to the distribution of the samples. In this paper, a color sampling method based on equi-visual perception is proposed to obtain approximate uniform color samples in CIEL*a*b* space. In order to evaluate transformation accuracy of proposed method, color space transformations are simulated using regression, 3D interpolation with LUT and neural network techniques, respectively.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.485-488
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• 2000

This paper proposes to design the residential power line communication device using Softwire Protocol, which targets the device with 8bit micro-controller and small-size memory based on low-rate power line communication network or wireless communication network. As a case study, the SCP message specification of air-conditioner that has capability of control and monitoring its status is designed using Softwire Protocol. And, it is described how the device operates sequentially.

• 한국정보전자통신기술학회논문지
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• 제12권2호
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• pp.150-154
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• 2019

In the design of semiconductor integrated circuits, ESD is one of the important issues related to product quality improvement and reliability. In particular, as the process progresses and the thickness of the gate oxide film decreases, ESD is recognized as an important problem of integrated circuit design. Many ESD protection circuits have been studied to solve such ESD problems. In addition, the proposed device can modify the existing SCR structure without adding external circuit to effectively protect the gate oxide of the internal circuit by low trigger voltage, and prevent the undesired latch-up phenomenon in the steady state with high holding voltage. In this paper, SCR-based novel ESD(Electro-Static Discharge) device with the high holding voltage has been proposed. The proposed device has the lower triggering voltage without an external trigger circuitry and the high holding voltage to prevent latch-up phenomenon during the normal condition. Using TCAD simulation results, not only the design factors that influence the holding voltage, but also comparison of conventional ESD protection device(ggNMOS, SCR), are explained. The proposed device was fabricated using 0.35um BCD process and was measured electrical characteristic and robustness. In the result, the proposed device has triggering voltage of 13.1V and holding voltage of 11.4V and HBM 5kV, MM 250V ESD robustness.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권9호
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• pp.2967-2981
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• 2014

Device-to-Device (D2D) communication is a technology component for long-term evolution-advanced (LTE-A). In D2D communication, users in close proximity to each other can communicate directly without going through a base station; such direct communication can improve spectral efficiency. Although D2D communication brings improvement in spectral efficiency, it also causes interference to the cellular network as a result of spectrum sharing. In particularly, D2D communication can generate interference for each D2D pair when the common wireless medium in a co-located limited area is accessed. Even though the interference management for between the D2D pair and cellular networks has been proposed, the interference reducing methods have still not been fully studied for the D2D pairs. In this paper, we investigate the problem of D2D pair coexistence in which interference is considered between D2D pairs. Using a signal to interference model for a target D2D pair, we provide an analysis of the aggregated throughput of a dense D2D network. For a target D2D pair, we assume that the desired signal and interference signals obey multipath fading and shadow fading. Through analysis, we demonstrate the effect of cluster size such as the number of D2D pairs and the size of the considered area on the network performance. The analytical results are compared with computer simulations. Our work can be used for a rough guideline for controlling the system throughput in a dense D2D network environment.

• Transactions on Electrical and Electronic Materials
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• 제18권2호
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• pp.70-73
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• 2017

We investigated n-i-p type single junction hydrogenated amorphous silicon oxide solar cells. These cells were without front surface texture or back reflector. Maximum power point efficiency of these cells showed that an optimized device structure is needed to get the best device output. This depends on the thickness and defect density ($N_d$) of the active layer. A typical 10% photovoltaic device conversion efficiency was obtained with a $N_d=8.86{\times}10^{15}cm^{-3}$ defect density and 630 nm active layer thickness. Our investigation suggests a correlation between defect density and active layer thickness to device efficiency. We found that amorphous silicon solar cell efficiency can be improved to well above 10%.

• International Journal of Internet, Broadcasting and Communication
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• 제7권2호
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• pp.113-116
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• 2015

Generally, in the railway vehicle the driving force of gravity happens by the high-speed running and the repetitive impulse cause the degradation and the malfunction phenomenon shows differently because the durability of each component changes according to the internal and external causes. The maintenance of propulsion control device which is played the very important role as to the stable service of the railway vehicle is greatly important among them. Therefore maintenance training propulsion control device simulator is needed to maximize learning through repetition and improve the maintenance practical skills training. This paper designed the railway vehicle running device with a miniature for the railway vehicle maintenance training and developed a propulsion control device simulator equipped the imitation steering wheel.