• Journal of information and communication convergence engineering
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• v.4 no.3
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• pp.97-100
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• 2006

In this paper, the transmission service for medical image is proposed via IEEE 802.15.4a on WPAN environment. Also, transmission and receiving performance of medical image using TH UWB-IR system is evaluated on indoor multi-path fading environment. On the results, the proposed scheme can solve the problem of interference from the medical equipment in same frequency band, and minimize the loss due to the indoor multi-path fading environment. Therefore, the transmission with low power usage is possible.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12B
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• pp.1548-1555
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• 2011

In ultra-deep submicron technology, minimization of propagation delay and power consumption on buses is one of the most important design objectives in system-on-chip (SOC) design. Crosstalk between adjacent wires on the bus may create a significant portion of propagation delay. Elimination or minimization of such faults is crucial to the performance and reliability of SOC designs. Most of the previous works on bus encoding are targeted either to minimize the bus switching or minimize the crosstalk delay, but not both. This paper proposes a new bus encoding scheme which can adaptively select one of functions "invert" and "logic-convert" according the number of bus switching on an encoded 4-bit cluster. This scheme leads to minimization of both crosstalk and bus switching. In experiment result, our proposed encoding technique consumes about 25% less power over the previous, while completely eliminating the crosstalk delay.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.12 s.354
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• pp.9-15
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• 2006

In this paper, signal processing techniques for noncoherent impulse-radio-based UWB (IR-UWB) communication system are proposed to provide system implementation of low power consumption and low complexity. The proposed system adopts a simple modulation technique of OOK (on-oft-keying) and noncoherent signal detection based on signal amplitude. In particular, a technique of a novel high speed digital sampler using a stable, lower reference clock is developed to detect nano-second pulses and recover digital signals from the pulses. Also, a 32 bits Turyn code for data frame synchronization and a convolution code as FEC are applied, respectively. To verify the proposed signal processing techniques for low power, low complexity noncoherent IR-UWB system, the proposed signal processing technique is implemented in FPGA and then a short-range communication system for wireless transmission of high quality MP3 data is designed and tested.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.237-239
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• 2005

This paper describes the ultra precise position estimation of a servomotor using sinusoidal encoder based on Arcsine Interpolation Method. The amplitude and offset errors of the sinusoidal encoder output signals are effectively compensated and on-line tuned by utilizing a low cost programmable differential amp without any special expensive equipments. To theoretically evaluate the practical resolution of this system, the relationship between the amplitude of A/D converter input signal errors and the anticipated resolution is briefly dealt with. The performance of the proposed method is verified by the experiments, by comparing it with position and speed control characteristics of the servomotor driving system using a digital incremental 50,000ppr encoder.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.7
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• pp.615-622
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• 2004

Recently, the hybrid system combining fuel cell and gas turbine has drawn much attention owing to its high efficiency and ultra low emission. It is now on the verge of world wide development and various system configurations have been proposed. A national project funded by Korean government has also been initiated to develop a pressurized hybrid system. This work aims at presenting design performance analysis for various possible system configurations as an initial step for the system development. Study focuses are given to major design options including the power ratio between gas turbine and fuel cell, reforming method (internal or external), reforming heat source (reforming burner, cathode hot air, fuel cell heat release) and steam supply method for reformer (anode gas recirculation, external steam generator). A wide variation in performance among different configurations has been predicted.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2119.1_2120.1
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• 2009

UWB(Ultra Wide Band)는 차세대 무선통신 기술로 무선 디지털펄스라고도 한다. GHz대의 주파수를 사용하면서도 초당 수천~수백만 회의 저출력 펄스로 이루어진 것이 큰 특징이다[1]. 기존 무선통신 기술의 양대 축인 IEEE 802.11과 블루투스 등에 비해 속도와 전력소모 등에서 월등히 앞서고 있으며, SoC(System on a Chip)의 저전력 구현에 대한 연구가 활발히 진행되고 있다. OFDM은 크게 FFT(Fast Fourier Transform) 블록, Interpolation /decimation 필터 블록, 비터비 블록, 변복조 블록, 등화기 블록 등으로 구성된다. 고속 시스템에서는 대역효율성이 우수한 OFDM(Orthogonal Frequency Division Multiplexing) 방식을 사용하고 있으며, OFDM 전송방식은 직렬로 입력되는 데이터 열을 병렬 데이터 열로 변환한 후에 부반송파에 실어 전송하는 방식이다. 이와 같은 병렬화와 부반송파를 곱하는 동작은 IFFT와 FFT로 구현이 가능한데, FFT 블록의 구현 비용과 전력소모를 줄이는 것이 핵심사항이라고 할 수 있다. 기존논문에서는 OFDM용 FFT 구조로 단일버터플라이연산자 구조, 파이프라인 구조, 병렬구조 등의 여러 구조가 제안되었다[2]. 본 논문에서는 Radix-8 FFT 알고리즘 기반의 New partial Arithmetic 저전력 FFT 구조를 제안하였다. 제안한 New partial Arithmetic 저전력 FFT구조는 곱셈기 대신 병렬 가산기를 이용 하여 지금까지 사용되는 FFT 구조보다 전력소모를 줄일 수 있음을 보였다.

• Journal of Advanced Navigation Technology
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• v.10 no.3
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• pp.268-275
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• 2006

The rapid proliferation of in-home and office information applications and services is driving the need for new wireless technologies enabling wideband short range multimedia communications. Due to the growing demand for higher quality media and faster wireless connections, several IEEE standardization groups are considering very high data rate alternatives physical layer(s) for Wireless Personal Area Network (WPAN). The Ultra Wide Band (UWB) multiple access technology based on very narrow pulse transmission, is one viable candidate for these applications providing very high bit rates services, low power consumption and accurate positioning capability. In this paper we provide a methodology to evaluate the UWB system BER performance in UWB wireless fading networks with power controlled UWB devices are considered. Results can be used to analyze the performance of a given network topology and to provide useful design ideas for an UWB home sensor network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11C
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• pp.1098-1105
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• 2009

In this paper, we propose an asynchronous UWB (Ultra Wide Band) Positioning scheme that can provide precise positioning performance with low complexity and low power consumption. We also present the residual test to improve the positioning performance in multipath channels having heavy NLoS (Non-Line of Sight) components. As compared to conventional ToA (Time of Arrival) positioning scheme that requires round-trip transmissions as many as the number of beacons, the proposed UWB positioning scheme effectively decrease power consumption and processing delay since a single round-trip transmission is only required. Also, as compared to conventional TDoA (Time Difference of Arrival) positioning scheme requiring precise synchronization among the beacons, asynchronous nature of the proposed scheme achieves very low system complexity. Through simulations in LoS (Line of Sight) channel models, we observe that the proposed scheme requires low system complexity, low power consumption, while providing positioning performance of almost the same accuracy as the conventional ToA and TDoA positioning schemes. In addition, the proposed scheme by employing the residual test achieves accurate positioning performance even in multipath channels having heavy NLoS components.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.11
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• pp.61-68
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• 2008

In this paper, we propose a RF front-end developments for vehicle UWB radar systems. UWB systems have a very narrow pulse width that is below 1ns. Therefore, UWB is designed to have broadband quality of low power several GHz and must coexist with the radio communication system. UWB's advantages include high channel capacity and data rate, because precise resolution for multi-path can easily position estimate and Rake receiver. Also, UWB has low interference because it displays broadband quality of low power. Positioning is made possible by short range accuracy, which can reduce the expense of system design. An RF front-end module is designed using the DCR(Direct ConveRsion) method and is composed in RF for vehicles at a low-cost.

• Transactions on Electrical and Electronic Materials
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• v.13 no.2
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• pp.69-72
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• 2012

In this study, deposition of low-dielectric constant SiOC(H) films by conventional plasma-enhanced chemical vapor deposition (PECVD) were investigated through various characterization techniques. The results show that, with an increase in the plasma power density, the relative dielectric constant (k) of the deposited films decreases whereas the refractive index increases. This is mainly due to the incorporation of organic molecules with $CH_3$ group into the Si-O-Si cage structure. It is as confirmed by FT-IR measurements in which the absorption peak at 1,129 $cm^{-1}$ corresponding to Si-O-Si cage structure increases with power plasma density. Electrical characterization reveals that even after fast thermal annealing process, the leakage current density of the deposited films is in the order of $10^{-11}$ A/cm at 1.5 MV/cm. The reliability of the SiOC(H) film is also further characterized by using BTS test.