• ETRI Journal
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• v.36 no.3
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• pp.498-501
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• 2014

A C-band 50 W high-power microwave monolithic integrated circuit amplifier for use in a phased-array radar system was designed and fabricated using commercial $0.25{\mu}m$ AlGaN/GaN technology. This two-stage amplifier can achieve a saturated output power of 50 W with higher than 35% power-added efficiency and 22 dB small-signal gain over a frequency range of 5.5 GHz to 6.2 GHz. With a compact $14.82mm^2$ chip area, an output power density of $3.2W/mm^2$ is demonstrated.

• ETRI Journal
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• v.27 no.2
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• pp.140-152
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• 2005

In this paper, we present design features, implementation, and validation of a satellite simulator subsystem for the Korea Multi-Purpose Satellite-2 (KOMPSAT-2). The satellite simulator subsystem is implemented on a personal computer to minimize costs and trouble on embedding onboard flight software into the simulator. An object-oriented design methodology is employed to maximize software reusability. Also, instead of a high-cost commercial database, XML is used for the manipulation of spacecraft characteristics data, telecommand, telemetry, and simulation data. The KOMPSAT-2 satellite simulator subsystem is validated by various simulations for autonomous onboard launch and early orbit phase operations, anomaly operation, and science fine mode operation. It is also officially verified by successfully passing various tests such as the satellite simulator subsystem test, mission control element system integration test, interface test, site installation test, and acceptance test.

• ETRI Journal
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• v.31 no.3
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• pp.247-253
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• 2009

We propose a Ku-band driver and high-power amplifier monolithic microwave integrated circuits (MMICs) employing a compensating gate bias circuit using a commercial 0.5 ${\mu}m$ GaAs pHEMT technology. The integrated gate bias circuit provides compensation for the threshold voltage and temperature variations as well as independence of the supply voltage variations. A fabricated two-stage Ku-band driver amplifier MMIC exhibits a typical output power of 30.5 dBm and power-added efficiency (PAE) of 37% over a 13.5 GHz to 15.0 GHz frequency band, while a fabricated three-stage Ku-band high-power amplifier MMIC exhibits a maximum saturated output power of 39.25 dBm (8.4 W) and PAE of 22.7% at 14.5 GHz.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.1
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• pp.62-68
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• 2007

H.264 video compression in digital multimedia broadcasting (DMB) shows significantly high compression ratio over conventional algorithms, while its required hardware cost and power consumption are also $3{\sim}5$ times larger. Consequently, low-hardware-cost and low-power H.264 decoder SoC is essential for commercial digital multimedia broadcasting terminals. This paper describes low-power design and implementation of core blocks in H.264 decoder SoC.

• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.285-289
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• 2005

In recent years, RFID is widely used in industrial applications including factory, material flow, logistics and defense areas. In this paper, we developed a RFID baseband system with ASK modulation and convolutional channel code. A commercial ASK RF module is used its frequency range in $350{\sim}351$MHz and power is 10mW and the convolution code is constraint length k=3 and rate R=1/2 The performance is measured implemented the binary search algorithm as anti-collision method and we show the wave shapes whit collision occurrence.

• Korean journal of communication and information
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• v.22
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• pp.7-38
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• 2003

This study is primarily concerned with the discussion about the crisis of Korean Public Service Broadcasting within the context of changing media environment. The study firstly attempts to explain the causes of current problems of Public Service Broadcasting in general, and categorizes the patterns of Western countries' reactions to cope with the problems. Secondly, the present study deals with the case of Korean Public Service Broadcasting. This paper argues that Korean Public Service Broadcasters have adopted four salient strategies: 1) They have tried to achieve high program ratings based on non-distinctive programming; 2) They have preferred the commercial advertising revenues as the primary financial resource; 3) They have attempted to expand their social power while exploiting their program contents; 4) Finally, they have tried to be a sole player in the decision making process, independent from all the other social forces such as the state, capital, and the civil organizations. This study suggests that four strategies should be reconsidered because those are far from the original ideas of Public Service Broadcasting.

• ETRI Journal
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• v.35 no.3
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• pp.378-385
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• 2013

An S-band multifunction chip with a simple interface for an active phased array base station antenna for next-generation mobile communications is designed and fabricated using commercial 0.5-${\mu}m$ GaAs pHEMT technology. To reduce the cost of the module assembly and to reduce the number of chip interfaces for a compact transmit/receive module, a digital serial-to-parallel converter and an active bias circuit are integrated into the designed chip. The chip can be controlled and driven using only five interfaces. With 6-bit phase shifting and 6-bit attenuation, it provides a wideband performance employing a shunt-feedback technique for amplifiers. With a compact size of 16 $mm^2$ ($4mm{\times}4mm$), the proposed chip exhibits a gain of 26 dB, a P1dB of 12 dBm, and a noise figure of 3.5 dB over a wide frequency range of 1.8 GHz to 3.2 GHz.

• Knowledge Management Research
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• v.10 no.2
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• pp.15-33
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• 2009

Telecommunications-broadcasting convergence in the domain of IT is a representative phenomenon that is expected to provide the saturated existing markets with a new source of profit. Especially, T-Commerce combines familiarity of TV and immediacy of the Internet which are expected to cover all the users familiar with each media and expand the existing commercial transactions. Telecommunications-broadcasting convergence in Korea, however, is focusing on technical and regulatory aspects so that research on the real users is not up to the mark yet. This is the most fundamental problem in hampering growth in the corresponding service and market. Thus, we are proposing an adoption model on T-Commerce to rapidly expand the convergence service through understanding the potential users. Perceived utilitarian and hedonic values, perceived interactivity, media substitution and personal innovativeness have been examined as the factors influencing the users' intention to adopt a new convergence service. As a result of empirical analysis, it is verified that perceived utilitarian and hedonic values and personal innovativeness directly influenced the users' intention to adopt whereas perceived interactivity had indirect affect on them. T-Commerce service providers should not only emphasize on the benefit that the older media could not provide the users with, but also provide them with more pleasure and entertaining experience during the course of satisfying the users' needs to distinguish T-Commerce from the other existing media.

• ETRI Journal
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• v.41 no.6
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• pp.850-862
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• 2019

This work investigated three-dimensional (3D) focused microwave thermotherapy (FMT) at 925 MHz for a human tissue mimicking phantom using the time reversal (TR) principle for musculoskeletal disorders. We verified the proposed TR algorithm by evaluating the possibility of 3D beam focusing through simulations and experiments. The simulation, along with the electromagnetic and thermal analyses of the human tissue mimicking phantom model, was conducted by employing the Sim4Life commercial tool. Experimental validation was conducted on the developed FMT system using a fabricated human tissue mimicking phantom. A truncated threshold method was proposed to reduce the unwanted hot spots in a normal tissue region, wherein a beam was appropriately focused on a target position. The validation results of the simulation and experiments obtained by utilizing the proposed TR algorithm were shown to be acceptable. Effective beam focusing at the desired position of the phantom could be achieved.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.3
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• pp.19-26
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• 2010

Since T-DMB commercial services have been launched, various broadcasting services such as DMB2.0, which provides interactive data broadcasting services, have emerged. Due to activation of T-DMB services, the needs of the existing video contents as well as new data contents are increasing. Especially, video contents are frequently reused because of the production cost of digitalized contents. In order to solve the problem occurring in the contents reusing process, this paper proposes the method controlling transfer rate by defining a numerical formula and verifies it through simulation.