An Effective TOA-based Localization Method with Adaptive Bias Computation

Go, Seung-Ryeol Institute of Korean Electrical and Electronics Eng 2016 전기전자학회논문지 Vol.20 No.1

In this paper, we propose an effective time-of-arrival (TOA)-based localization method with adaptive bias computation in indoor environments. The goal of the localization is to estimate an accurate target's location in wireless localization system. However, in indoor environments, non-line-of-sight (NLOS) errors block the signal propagation between target device and base station. The NLOS errors have significant effects on ranging between two devices for wireless localization. In TOA-based localization, finding the target's location inside the overlapped area in the TOA-circles is difficult. We present an effective localization method using compensated distance with adaptive bias computation. The proposed method is possible for the target's location to estimate an accurate location in the overlapped area using the measured distances with subtracted adaptive bias. Through localization experiments in indoor environments, estimation error is reduced comparing to the conventional localization methods.

Arbitrary Waveform Generation via Spectral Line-by-Line Pulse Shaping on Mode-Locked Pulses

Seo, Dong-Sun,Jiang, Zhi,Weiner, Andrew M. Institute of Korean Electrical and Electronics Eng 2006 전기전자학회논문지 Vol.10 No.2

We have built a grating-based, high-resolution, spectral line-by-line pulse shaper. By controlling individual spectral lines of a mode-locked laser output, we demonstrate the interesting functionalities of the pulse shaper for arbitrary waveform generation, such as width tunable pulse generation, phase controlled waveform generation, microwave waveform generation, etc.

A New Integral Variable Structure Controller For Incorporating Actuator Dynamics

Lee, Jung-Hoon Institute of Korean Electrical and Electronics Eng 2006 전기전자학회논문지 Vol.10 No.2

In this paper, a new simple integral variable structure controller is designed with incorporating the actuator dynamics. The formulation of the VSS (variable structure system) controller design includes integral augmented sliding surface and the dynamics of the actuator expressed as the state equation. An illustrative example is given to show the effectiveness of the developed controller.

Analyses of the Effect of Inserting Border Lines between Adjacent Color Regions on Detecting Boundaries

유현중,김우성,장영범,Yoo, Hyeon-Joong,Kim, Woo-Sung,Jang, Young-Beom Institute of Korean Electrical and Electronics Eng 2006 전기전자학회논문지 Vol.10 No.1

이 논문은 에지 검출을 위해 다른 컬러 영역사이의 테두리선을 삽입한 효과를 분석한다. 컬러코드를 인식하는 새로운 알고리즘을 제안하지는 않는다. RFID 방식을 보상하고, 디지털 카메라의 이용률이 높아져서 컬러코드에 대한 관심이 매우 증가하고 있다. 그러나 컬러의 왜곡이 심해지면 컬러코드의 확산을 저하시키게 된다. 왜곡된 컬러의 효과를 감소시키기위해서 영역내 화소 각각의 특성보다 각 영역 전체의 화소를 통계적으로 처리하는 방법이 바람직하다. 이 처리를 위해서 영상 영역화가 필요하다. 연결되지 않은 에지를 검출하기 위해 인접 컬러 영역사이에 2 화소 크기의 테두리선을 삽입한다. 테두리선은 흰색, 검은색 경계선이 사용된다. 2 종류의 테두리선이 삽입된 영상에 대한 에지 검출이 수행되고, 그 결과가 테두리선이 삽입되지 않은 에지 검출 결과와 비교한다. 검은 테두리선을 삽입한 결과는 지퍼효과에 의해 에지 검출 능력이 저하되고, 흰 테두리선을 삽입한 결과는 삽입하지 않은 경우보다 에지 검출 능력이 향상되었다. This paper presents the analyses of the effect of inserting border lines between different color regions on edge detection in color codes, and is not intended to present any new algorithm for color-code recognition. With its role to complement the RFID (radio frequency identification) and the wide and fast spread of digital cameras, an interest on color codes is fast increasing. However, the severe distortion of colors in obtained images prohibits color codes from expanding their applications. To reduce the effect of color distortion it is desirable to process the whole pixels in each color region statistically, instead of relying on some pixels sampled from the region. This requires segmentation, and the segmentation usually requires edge detection. To help detect edges not disconnected, we inserted border lines of the width of two pixels between adjacent color regions. Two colors were used for the border lines: one consisting of white pixels, and the other black pixels. The edge detection was performed on images with either of the two kinds of border lines inserted, and the results were compared to results without inserted border lines. We found that inserting black border lines degraded edge detection by causing zipper effect while inserting white border lines improved it compared to the cases without inserted border lines.

Run and Go Algorithm for Blind Equalization

정원주,Chung, Won-Zoo Institute of Korean Electrical and Electronics Eng 2006 전기전자학회논문지 Vol.10 No.1

이 논문은 high order statistics 에 기반을 둔 자력복구 알고리듬과 판정-LMS 를 조합하는 자력복구 적응 채널등화기를 제안한다. 저 신뢰도 신호에 대하여 적응을 멈추는 기존의 "Stop-and-Go" 알고리듬과는 달리 제안된 알고리듬은 저 신뢰도 신호에 대하여 자력복구 알고리듬 적응을 이용하기에 "Run-and-Go"라고 명명하였으며 판정-LMS의 최소 MSE 성능과 자력복구 알고리듬의 신호 획득능력의 시너지 효과를 가진다. 제안된 알고리듬은 신뢰도 구간을 신호의 질에 따라 자동설정 함으로 수렴 속도와 신호 획득 능력을 각각 개선한다. In this paper, we propose an adaptation strategy for blind equalizers, which combines a blind algorithm based on high order statistics and the decision directed LMS algorithm. In contrast to 'Stop-and-Go' algorithm, where adaptation is stopped for unreliable signals, the proposed algorithm applies high order statistics (HOS) blind algorithm to the unreliable signals and applies DD-LMS for the reliable signals. The proposed algorithm, named 'Run-and-Go' algorithm, inherits minimum MSE performance of DD-LMS and acquisition ability of blind algorithms. Furthermore, by updating the reliable signal region according to signal quality in each iteration, the convergence speed and acquisition ability is further improved.

3.125Gbps Reference-less Clock and Data Recovery using 4X Oversampling

장형욱,강진구,Jang, Hyung-Wook,Kang, Jin-Ku Institute of Korean Electrical and Electronics Eng 2006 전기전자학회논문지 Vol.10 No.1

본 논문에서는 기준동작 클럭없이 데이터만으로 구현되는 반주기의 4x 오버샘플링 위상/주파수검출기를 이용한 클럭 데이터 복원회로에 대하여 서술하였다. 위상 및 주파수검출기는 4x 오버샘플링 기법을 이용하여 설계되었다. 위상검출기는 뱅뱅 제어방법에 의해, 주파수검출기는 로테이션방법에 의해 동작한다. 위상 및 주파수 검출기로부터 발생된 6개의 신호들은 전하펌프로 들어갈 전하량을 결정한다. VCO단은 4개의 차동 지연단으로 구성되고 8개의 클럭신호를 생성한다. 제안된 회로는 공급전압 1.8V, 0.18um MOCS 공정으로 설계 시뮬레이션되었다. 제안된 구조의 PD와 FD를 사용하여 25%의 넓은 트래킹 주파수 범위를 가진다. In this paper, a clock and data recovery (CDR) circuit for a serial link with a half rate 4x oversampling phase and frequency detector structure without a reference clock is described. The phase detector (PD) and frequency detector (FD)are designed by 4X oversampling method. The PD, which uses bang-bang method, finds the phase error by generating four up/down signal and the FD, which uses the rotational method, finds the frequency error by generating up/down signal made by the PD output. And the six signals of the PD and the FD control an amount of current that flows through the charge pump. The VCO composed of four differential buffer stages generates eight differential clocks. Proposed circuit is designed using the 0.18um CMOS technology and operating voltage is 1.8V. With a 4X oversampling PD and FD technique, tracking range of 24% at 3.125Gbps is achieved.

A Design of LC-tuned Sinusoidal VCOs Using OTA-C Active Inductors

Chung, Won-Sup,Son, Sang-Hee Institute of Korean Electrical and Electronics Eng 2007 전기전자학회논문지 Vol.11 No.3

Sinusoidal voltage-controlled oscillators (VCOs) based on Colpitts and Hartley oscillators are presented. They consist of a LC parallel-tuned circuit connected in a negative-feedback loop with an OTA-R amplifier and two diode limiters, where the inductor is simulated one realized with temperature-stable linear operational transconductance amplifiers (OTAs) and a grounded capacitor. Prototype VCOs are built with discrete components. The Colpitts VCO exhibits less than 1% nonlinearity in its current-to-frequency transfer characteristic from 4.2 to 21.7 MHz and ${\pm}$95 ppm/$^{\circ}C$ temperature drift of frequency over 0 to $70^{\circ}C$. The total harmonic distortion (THD) is as low as 2.92% with a peak-to-peak amplitude of 0.7 V for a frequency-tuning range of 10.8-32 MHz. The Hartley VCO has the temperature drift and THD of two times higher than those of the Colpitts VCO.

Micro/Millimeter-wave Photonic Pulse Train Generation by using Low-Speed Electronics and Optical Repetition Rate Multiplication

Lee, J.M.,Seo, D.S. Institute of Korean Electrical and Electronics Eng 2007 전기전자학회논문지 Vol.11 No.3

20 GHz and 40 GHz micro/millimeter-wave photonic pulse trains have been generated from a fiber ring laser with a semiconductor optical amplifier (SOA) by injecting 2 GHz gain-switched Fabry-Perot laser diode (GS-FPLD) output. To achieve efficient cross-gain modulation in the SOA at 20 GHz and 40 GHz, individual lasing modes of the 2 GHz GS-FPLD output separated to 25 and 50 picoseconds respectively by passing dispersion compensating fibers.

Pseudo-Orthogonal Space-Time Block Codes for MIMO-OFDM Systems over Frequency-Selective Channels

이흔철,박석환,이인규,Lee, Heun-Chul,Park, Seok-Hwan,Lee, In-Kyu Institute of Korean Electrical and Electronics Eng 2007 전기전자학회논문지 Vol.11 No.4

This paper proposes a new class of Space-Time Block Codes, which is manipulated from the existing transmit diversity schemes. We analyze the performance and the receiver complexity of the proposed scheme and confirm that the new diversity scheme can yield performance gain over other existing four-transmit antenna cases. By relaxing the diversity criterion on code designs, the proposed space-time code provides a full transmission rate for four-transmit antennas and makes it possible to approach the open-loop Shannon channel capacity. Outage capacity and simulation results are used to show that substantial improvements in performance while maintaining a simple linear processing receiver structure are obtained in frequency selective channels.

Fast Charging Photoflash Capacitor Charger with Wide Range Current Limiter

Choi, Won-Ho,Lee, Woo-Kwan,Kim, Soo-Won Institute of Korean Electrical and Electronics Eng 2007 전기전자학회논문지 Vol.11 No.4

The fast charging photoflash capacitor charger with wide range current limiter is presented. By using proposed control logic block and wide range current limiter, the photoflash capacitor charger can reduce charging time and control life of battery for user convenience. The proposed photoflash capacitor charger has 3s charging time at 3.3V battery voltage, 1.2A current limit condition. It is well-suited for portable device application like digital camera, digital video camera, and mobile phone with camera.