• JSTS:Journal of Semiconductor Technology and Science
• /
• 제7권4호
• /
• pp.267-273
• /
• 2007

A fractional-N frequency synthesizer supports quadruple bands and multiple standards for mobile broadcasting systems. A novel linearized coarse tuned VCO adopting a pseudo-exponential capacitor bank structure is proposed to cover the wide bandwidth of 65%. The proposed technique successfully reduces the variations of KVCO and per-code frequency step by 3.2 and 2.7 times, respectively. For the divider and prescaler circuits, TSPC (true single-phase clock) logic is extensively utilized for high speed operation, low power consumption, and small silicon area. Implemented in $0.18-{\mu}m$ CMOS, the PLL covers $154{\sim}303$ MHz (VHF-III), $462{\sim}911$ MHz (UHF), and $1441{\sim}1887$ MHz (L1, L2) with two VCO's while dissipating 23 mA from 1.8 V supply. The integrated phase noise is 0.598 and 0.812 degree for the integer-N and fractional-N modes, respectively, at 750 MHz output frequency. The in-band noise at 10 kHz offset is -96 dBc/Hz for the integer-N mode and degraded only by 3 dB for the fractional-N mode.

• 한국식품과학회지
• /
• 제36권3호
• /
• pp.518-521
• /
• 2004

이상계 용매시스템을 이용하여 물질을 고순도로 대량 분리 할 수 있는 기술인 countercurrent chromatography를 이용하여 인삼으로부터 생리황성 성분인 saponin을 대량 분리 농축하였다. 용매 조성별 인삼 saponin의 분배계수에 따른 인삼 saponin 분리에 적합한 용매시스템은 chloroform/methanol/water(40/39/21, v/v/v)으로 결정되었으며 HSCCC의 작동 조건은 chloroform/methanol/water 용매시스템의 하층부를 이동상으로 한 head to tail mode에서 이동상의 유속 5mL/min, 인삼추출물 injection량 $200{\mu}L$, 컬럼회전속도 800 rpm의 조건이 적합한 것으로 판단되었다. 이러한 조건하에서 분리된 인삼saponin의 양은 $550.7{\mu}g$으로 HSCCC에 주입한 인삼 추출물 $200{\mu}L$중에 존재하는 총 saponin의 양 $865.5{\mu}g$에 비교하여 전체 수율은 63.6%로 나타났으며 TLC로 각 분획의 순도를 확인할 수 있었다.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제6권3호
• /
• pp.154-161
• /
• 2006

This paper describes the new types of ngative differential resistance (NDR) IC applications which use a monolithic quantum-effect device technology based on the RTD/HBT heterostructure design. As a digital IC, a low-power/high-speed MOBILE (MOnostable-BIstable transition Logic Element)-based D-flip flop IC operating in a non-return-to-zero (NRZ) mode is proposed and developed. The fabricated NRZ MOBILE D-flip flop shows high speed operation up to 34 Gb/s which is the highest speed to our knowledge as a MOBILE NRZ D-flip flop, implemented by the RTD/HBT technology. As an analog IC, a 14.75 GHz RTD/HBT differential-mode voltage-controlled oscillator (VCO) with extremely low power consumption and good phase noise characteristics is designed and fabricated. The VCO shows the low dc power consumption of 0.62 mW and good F.O.M of -185 dBc/Hz. Moreover, a high-speed CML-type multi-functional logic, which operates different logic function such as inverter, NAND, NOR, AND and OR in a circuit, is proposed and designed. The operation of the proposed CML-type multi-functional logic gate is simulated up to 30 Gb/s. These results indicate the potential of the RTD based ICs for high speed digital/analog applications.

• 한국컴퓨터정보학회논문지
• /
• 제11권1호
• /
• pp.243-250
• /
• 2006

모바일 단말기 장치가 발전하면서 컴퓨터로만 할 수 있었던 게임, 인터넷, 금융 서비스 등을 이동 단말기를 이용하여 처리할 수 있다. 본 논문에서는 펜티엄급 PC에서 유행하던 게임을 이동 단말기에서 재생가능성 하도록 재구성하고, 자동화 가능한 재구성 요소를 정리하여 아바타 변환기로 개발하고자 한다. 즉, 기존의 자원을 최대한 재활용하여 이동 단말기용 컨텐츠 개발 속도를 향상시킬 수 있는 방법을 제안하고자 한다. 플랫폼의 제약사항을 고려하여 기존의 컴퓨터의 아키텍처를 모바일 플랫폼에서 동작 가능한 로직과 리소스로 구분하여 변환하는 동작이 아바타 변환기의 주 기능이다. 이동 통신 사업자의 플랫폼 종류에 따른 다수의 컨텐츠 개발에 공용의 로직과 리소스를 변환함으로써 개발 속도를 향상시킬 수 있다.

• 한국임상보건과학회지
• /
• 제5권4호
• /
• pp.1015-1020
• /
• 2017

Purpose. Walking depends on the speed and type of shoe to be worn, and the degree of impact varies with the muscle used. In addition, the speed can be changed by moving objects and using objects when walking. This study analyzed the change of walking speed by applying various factors influencing walking. Methods. A total of 60 patients who had not undergone musculoskeletal diseases during the last 1 year were included. Shoe type was divided into slippers and shoe heels. Behavioral types were divided into bagging, books, and cell phone use. The walking speed was measured by the general walking, the middle walking, and the fast walking. The time was measured using a 10M linear distance test. The collected data were analyzed with SPSS program for independent samples t-test, one-way ANOVA. Results. There was a statistically significant difference according to the type of shoes when walking. Walking speed was slow in shoe heel. In addition, There was statistically significant difference according to type of behavior task at walking. Walking speed was slow in task type using mobile phone during walking. Conclusions. The walking speed were appeared difference in each type of shoe heel, using mobile phone.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1993년도 하계학술대회 논문집 B
• /
• pp.1020-1022
• /
• 1993

The speed control associated with do send motors for direct-drive applications of mobile robot is considered. In odor to the high-performance operation of dc servo motor, drive circuits is controlled Pulse Width Modulations. In this case, PWM driving circuit has nonliner charactristics. This circuit composed of H-type bridge with freewheeling diodes in odor to deal with storage energy of motor's inductance and also control method is developed. At resultes, speed charactristics of motor is shown lineristics. In oder to speed control of motor. The opertion of phase-locked servo system is described and a linear discrete model is developed to their behavior. Thise model discussed are the design problems, speed variation.

• 한국정보과학회논문지:정보통신
• /
• 제33권3호
• /
• pp.269-276
• /
• 2006

본 논문은 고속철도 환경에서 이중 이동 라우터를 이용한 끊김없는 핸드오버 방안을 제안한다. 제안한 방안은 철도차량의 앞과 뒤에 두 개의 이동 라우터를 배치하여 핸드오버 수행시기 차이를 이용한다. 이중 이동 라우터 중 하나가 핸드오버를 수행하더라도 다른 이동 라우터가 계속해서 패킷을 수신할 수 있으므로 네트워크 전체적으로는 끊김없는 서비스가 가능하지만, 두 개의 이동 라우터는 논리적으로 하나로 동작하게 된다. 수학적 해석 및 시뮬레이션 결과 제안한 방안은 핸드오버 시 서비스 중단 시간 및 패킷 손실을 방지할 수 있음을 알 수 있었다.

• 제어로봇시스템학회논문지
• /
• 제12권3호
• /
• pp.208-220
• /
• 2006

Energy of wheeled mobile robot is usually supplied by batteries. In order to extend operation time of mobile robots, it is necessary to minimize the energy consumption. The energy is dissipated mostly in the motors, which strongly depends on the velocity profile. This paper investigates various 3-step (acceleration - cruise - deceleration) speed control methods to minimize a new energy object function which considers the practical energy consumption dissipated in motors related to motor control input, velocity profile, and motor dynamics. We performed an analysis on the energy consumption various velocity profile patterns generated by standard control input such as step input, ramp input, parabolic input, and exponential input. Based on these standard control inputs, we analyzed the six 3-step velocity profile patterns: E-C-E, P-C-P, R-C-R, S-C-S, R-C-S, and S-C-R (S means a step control input, R means a ramp control input, P means a parabolic control input, and E means an exponential control input, C means a constant cruise velocity), and suggested an efficient iterative search algorithm with binary search which can find the numerical solution quickly. We performed various computer simulations to show the performance of the energy-optimal 3-step speed control in comparison with a conventional 3-step speed control with a reasonable constant acceleration as a benchmark. Simulation results show that the E-C-E is the most energy efficient 3-step velocity profile pattern, which enables wheeled mobile robot to extend working time up to 50%.

• ETRI Journal
• /
• 제40권1호
• /
• pp.39-50
• /
• 2018

More people prefer using rail traffic for travel or for commuting owing to its convenience and flexibility. The railway scenario has become an important communication scenario in the fifth generation era. The communication system should be designed to support high-data-rate demands with seamless connectivity at a high mobility. In this paper, the channel characteristics are studied and modeled for the railway tunnel scenario with straight and curved route shapes. On the basis of measurements using the "Mobile Hotspot Network" system, a three-dimensional ray tracer (RT) is calibrated and validated for the target scenarios. More channel characteristics are explored via RT simulations at 25.25 GHz with a 500-MHz bandwidth. The key channel parameters are extracted, provided, and incorporated into a 3rd-Generation-Partnership-Project-like stochastic channel generator. The necessary channel information can be practically realized, which can support the link-level and system-level design of the communication system in similar scenarios.

• 반도체디스플레이기술학회지
• /
• 제14권4호
• /
• pp.56-60
• /
• 2015

Mobile devices like smartphones and tablets are becoming increasingly capable in terms of processing power. Although they are already used in computer vision, no comparable measurement experiments of the popular feature extraction algorithm have been made yet. That is, local feature descriptors are widely used in many computer vision applications, and recently various methods have been proposed. While there are many evaluations have focused on various aspects of local features, matching accuracy, however there are no comparisons considering on speed trade-offs of recent descriptors such as ORB, FAST and BRISK. In this paper, we try to provide a performance evaluation of feature descriptors, and compare their matching precision and speed in KD-Tree setup with efficient computation of Hamming distance. The experimental results show that the recently proposed real valued descriptors such as ORB and FAST outperform state-of-the-art descriptors such SIFT and SURF in both, speed-up efficiency and precision/recall.