• Journal of Convergence Society for SMB
• /
• v.4 no.1
• /
• pp.1-6
• /
• 2014

PB/MC-CDMA is an efficient system which divides the whole frequency band into several blocks, unlike a conventional MC-CDMA system. We propose an efficient resource allocation scheme in Multi-Block PB/MC-CDMA (Partial Block Multi-Carrier Code Division Multiple Access). This system aims to improve frequency efficiency and maximize the total throughput while satisfying predefined threshold over various channel conditions. Through computer simulations, we confirm that the performance of the proposed system is more effective in terms of throughput.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.6
• /
• pp.155-161
• /
• 2015

As the popularity of the smartphone becomes increase, indoor smartphone positioning technology has been actively studied. The acoustic signal generated from the smartphone is received from the several microphones at the relative positioning system, and the trigger signal is proposed to mitigate the multipath effect and the effect is verified. But for the simple trigger method, there would be error occurred according to the variation of the distance or surrounding noise. In this paper, in order to resolve the problems, the dynamic trigger threshold technology is proposed and its effect is verified by the experiment.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.7B
• /
• pp.892-896
• /
• 2011

This paper proposes a two-stage synchronization scheme using a serial search non-coherent correlator appropriate for the IEEE 802.15.4a system. The proposed method improved the synchronization performance by using multi-pulse signals unlike the conventional method using single-pulse signals. It also compensated for the degradation of performance at low SNR resulting from the use of fixed threshold by applying the adaptive threshold technique. The proposed method showed a detection probability that is higher by approximately 0.2-0.3 compared with the conventional method in the IEEE 802.15.4a channel model.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.3
• /
• pp.575-583
• /
• 2013

In ad hoc networks, a distributed timing synchronization is studied using a firefly-inspired approach. We illuminate the exiting synchronization algorithm based on the theory of pulse-coupled oscillators so that the algorithm can be applied to multi-carrier systems through packet-based communications, where nodes communicate over an orthogonal frequency-division multiple access air interface. As our main result, we introduce a new sync-code detector, which optimally designs both the coupling function and the detection threshold when various network parameters such as the number of nodes in the network and network topology are given a priori. Computer simulations are performed to show the convergence to a synchronized state in realistic network environments.

• The KIPS Transactions:PartB
• /
• v.14B no.3 s.113
• /
• pp.191-198
• /
• 2007

In this paper, we present a marker detection and recognition method from camera image for a disabled person to interact with a server system which can control appliance of surrounding environment. It converts the camera image to a binary image by using multi-threshold and extracts contours of objects in the binary image. After that, it approximates the contours to a list of line segments. It finds rectangular markers by using geometrical features which are extracted from the approximated line segments. It normalizes the shape of extracted markers into exact squares by using the warping technique. It extracts feature vectors from marker image by using principal component analysis and then recognizes the marker. The proposed marker recognition system is robust for light change by using multi-threshold. Also, it is robust for angular variation of camera by using warping technique and principal component analysis. Experimental results show that the proposed method achieves 100% recognition rate at maximum for 21 markers and execution speed of 12 frames/sec.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.18 no.11
• /
• pp.2607-2612
• /
• 2014

In this paper, we propose a distributed user scheduling with transmit power control based on the amount of interference inflicted to other BSs in multi-cell uplink networks. Assuming that the channel reciprocity time-division duplexing(TDD) system is used, the channel state information (CSI) can be obtained at each user from pilot signals from other BSs. The amount of generating interference to other BSs will be calculated at each user. Especially, in this paper, we propose the threshold-based transmit power control, in which a user decrease its transmit power if its generating interference to other BSs is larger than a predetermined threshold. Simulation results show that the proposed technique significantly outperforms the existing user scheduling algorithms.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.36S no.11
• /
• pp.95-101
• /
• 1999

In this paper, we propose an adaptive method of tracking multiple moving objects using contour and features in surrounding conditions. We use an adaptive background model for robust processing in surrounding conditions. Object segmentation model detects pixels thresholded from local difference image between background and current image and extracts connected regions. Data association problem is solved by using feature extraction and object recognition model in searching window. We use Kalman filters for real-time tracking. The results of simulation show that the proposed method is good for tracking multiple moving objects in highway image sequences.

• Proceedings of the Korean Information Science Society Conference
• /
• 2003.10c
• /
• pp.175-177
• /
• 2003

본 논문에서는 직교 주파수 분할 다중화 전송방식(OFDM:Orthogonal Frequency Division Multiplexing)에서 비트 오류율(BER)과 시스템에서 사용할 수 있는 총 송신 파워가 제한된 상태에서 데이터 전송률을 최대화 시키는 기법을 제안한다. 제안한 기법은 미리 계산된 비트수별 신호대잡음비 임계값(threshold)과 부반송파의 신호대잡음비를 비교한 후 부반송파별 송신 파워를 최적화 시켜 비트를 할당한다. 이 기법은 송신 파워 및 비트를 할당하는 최적의 기법이라고 알려진 Hughes­Hartogs 기법과 거의 동일한 데이터 전송률을 가질 수 있으면서, 부반송파의 송신 파워 및 비트수를 할당하기 위해 필요한 반복작업을 줄일 수 있다.

• Journal of Advanced Navigation Technology
• /
• v.15 no.6
• /
• pp.1132-1137
• /
• 2011

In this paper, we propose Modified Multi CAMShift Algorithm(Modified Multi Continuously Adaptive Mean Shift Algorithm) that extracts skin color area and tracks several human body parts for real-time human tracking system. Skin color area is extracted by filtering input image in predefined RGB value range. These areas are initial search windows of hands and face for tracking. Gaussian background model prevents search window expending because it restricts skin color area. Also when occluding between these areas, we give more weights in occlusion area and move mass center of target area in color probability distribution image. As result, the proposed algorithm performs better than the original CAMShift approach in multiple object tracking and even when occluding of objects with similar colors.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.39 no.3
• /
• pp.61-72
• /
• 2002

In this paper, we propose two timing-driven routing algorithms for single-source net and multi-source net as applications of 1-Steiner heuristic algorithm. Using the method of substituting the cost of 1-Steiner heuristic algorithms with interconnection delay, our routing algorithms can route both single-source net and multi-source net which have all critical source-terminal pairs or one critical pair efficiently Our single-source net routing algorithm reduced the average maximum interconnection delay by up to 2.1% as compared with previous single-source routing algorithm, SERT, and 10.6% as compared with SERT-C. and Our multi-source net routing algorithm increased the average maximum interconnection delay by up to 2.7% as compared with MCMD A-tree, but outperforms it by up to average 1.4% when the signal net has only subset of critical node pairs.