• Journal of the Korea Society of Computer and Information
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• v.19 no.12
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• pp.91-100
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• 2014

In this paper, we categorize existing human gesture recognition technologies to camera-based, additional hardware-based and frequency-based technologies. Then we describe several representative techniques for each of them, emphasizing their strengths and weaknesses. We define important performance issues for human gesture recognition technologies and analyze recent technologies according to the performance issues. Our analyses show that camera-based technologies are easy to use and have high accuracy, but they have limitations on recognition ranges and need additional costs for their devices. Additional hardware-based technologies are not limited by recognition ranges and not affected by light or noise, but they have the disadvantage that human must wear or carry additional devices and need additional costs for their devices. Finally, frequency-based technologies are not limited by recognition ranges, and they do not need additional devices. However, they have not commercialized yet, and their accuracies can be deteriorated by other frequencies and signals.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4A
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• pp.458-465
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• 2004

To reaffirm the use of a mainstream CMOS process for designing passive-like attenuator structures, a linearly controlled variable attenuator is realized with 0.35${\mu}{\textrm}{m}$ 2-poly 4-metal CMOS process. It uses the П configuration for large attenuation range and suitable matching property. Compared to conventional passive-like CMOS attenuators, it is demonstrated that this work advances the frequency band from MHz to ㎓ (DC- l㎓), and reduces the size to 700${\mu}{\textrm}{m}$${\times}$300${\mu}{\textrm}{m}$.. Both simulation results and test results are provided. They show the improved linear relation between attenuation and control voltage. It is very useful in CDMA or GSM band, which uses under 1㎓ frequency band. An alternative topology, Bridged-T configuration, is proposed to get over the limit of applications by elevating operation bandwidth. The proposed topology covers over DC-2㎓ frequency band, which means that the proposed architecture can cover the tripleband (800MHz CDMA/GSM, 1.5㎓ GPS, 1.9㎓z PCS system) in applications as well. The simulation results are provided.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.435-438
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• 2003

The MS card data transfer system using blue-tooth protocol ran communicate the MS card data wirelessly and does not take an extra communication expense which is a weakness point of existing wireless communication system. This Blue-tooth system, which has excellent security and no extra communication expense, can efficiently communicate data of the place ,where can be solved with small scale wireless network, such as the theme-park or gasoline-station. Existing wireless communication system compose network using wireless-LAN protocol which has extra communication expense, or with RF protocol which has poor security. But this system suitable for LAN because it has not extra communication expense and it has excellent security cause frequency-hopping of Blue-tooth protocol. The MS card data transfer system using blue-tooth protocol has low power, high performance RISC processor and large scale 16-gray graphic LCD which is suitable for portable unit. The MS card data transfer system can efficiently control depot for a long time because it has low power, excellent security and no extra communication expense.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.6
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• pp.124-132
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• 2011

In a modern electronic warfare, radar signal environments become more denser and complex. Therefor the capability of reliable signal analysis techniques is required for ES(Electronic warfare Support) system to identify and analysis individual emitter signals from received signals. In this paper, we propose the new signal grouping algorithm to ensure the reliable signal analysis and to reduce the cost of the signal processing steps in the ES. The proposed grouping algorithm uses KDE(Kernel Density Estimator) and its CDF(Cumulative Distribution Function) to compose windows considering the statistical distribution characteristics based on the radar frequency modulation type. Simulation results show the good performance of the proposed technique in the signal grouping.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.2
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• pp.179-188
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• 2015

Testing a radar system in real environment requires a lot of time and cost. Thus various target simulators are developed to evaluate the radar performance and its functions as well. In order to enhance the range resolution and the accuracy for tracking, recent radar system tends to use the wideband signal. In this paper, we summarize two target simulation methods - the direct sampling method with the digital memories and the beat frequency generation for the stretch processing - and suggest the condition to improve their performance for a wideband radar system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.8
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• pp.777-783
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• 2009

In this paper, we implemented a wireless power transmission system at 2.45 GHz. The transmission power is limited within 20 dBm according to the ISM frequency regulations. We used two zero-bias Schottky diode and optimized the RF-DC converter for working a clock at 80 cm distance using a receiver with a single antenna and an Rf-DC converter to reduce parts and cost compared to previously reported literatures.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.5
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• pp.500-506
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• 2002

This paper presents a design of wide angle steering microstrip Rotman lens operating over broadband frequency range for Electronic Warfare equipments. It has a compact and simple structure which it is easy to manufacture repetitively. The lens is modelled as a 2-dimension planar circuit, the contour integral method is performed over entire lens contour and the transmission coefficients from 8 beam ports to 8 array ports are found. The measured results are well agreed with those of analysis. Prediction of the multibeam array pattern fed by linear array antenna shows $\pm$65$^{\circ}$ of beam steering and $\pm$5 dB insertion loss deviation over 3:1 frequency range.

• Journal of the Korea Convergence Society
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• v.11 no.8
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• pp.1-6
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• 2020

There are various approaches to evaluate a watermelon sweetness. However, there are some limitations to evaluating cost, watermelon damage, and subjective issue. In this study, we developed a novel approach to predict a watermelon sweetness using reflected sound and the machine learning algorithm. It was observed that higher brix watermelon produced higher spectral power is reflected sound. Based on the spectral-temporal features of reflected sound, the machine learning algorithms could accurately predict the sweetness group at a rate of 83.2 and 59.6 % in 2-groups and 3-groups classification, respectively.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.4
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• pp.118-124
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• 2010

We proposed a goods load simulator for optimum RFID distribution, which includes experiment process modeling guidelines for stable RFID scan rate, efficient cost-reduction of RFID application or even speedy management of RFID field. We show verification of this simulator using field test of distribution, and the proposed simulator has better performance than the classic method, and demonstrate the proposed is efficient method of draw up guidelines on RFID distribution.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.4
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• pp.121-126
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• 2010

Regarding HEMP has been studied as few thousand of paper by major nuclear bomb holding countries with USA for the self protection against nuclear bomb attract. Major HEMP protection facilities are consist of the shielding, filtering, grounding and high voltage protection circuits. Shielding room construction required a highest cost among the key protective facilities. Most of a theoretical formulas listed on the paper and related books has a little correlations in the certain frequency band between the theoretical formulas and field measuring results. For the reasons we proposed the advanced new theoretical formulas and developed the computer simulation S/W as enough as apply to the cost effective shielding room design for HEMP considering the various structural constants.