• Title/Summary/Keyword: Mobile frame

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Effective Noise Reduction in Mobile Communication Environment using Adaptive Comb Filtering (Adaptive Comb Filtering을 이용한 이동 통신 환경에서의 효과적인 잡음 제거)

  • Park Jeong-Sik;Jung Gue-Jun;Oh Yung-Hwan
    • Proceedings of the KSPS conference
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    • 2003.05a
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    • pp.203-206
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    • 2003
  • In this paper, we employ the adaptive comb filtering for effective noise reduction in mobile communication environment. Adaptive comb filtering is a well- known method for noise reduction, but requires the correct pitch period and must be applied just in voiced speech frames. To satisfy these requirements we use two kinds of information extracted from speech packets, one of which is the pitch period information measured precisely by a speech coder and the other is the frame rate information related to a decision on speech or silence frame. Experiments on speech recognition system confirm the efficiency of this method. Feature parameters employing this method give superior performance in noise environment to those extracted directly from output speech.

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Implementation of an Indoor Mobile Robot and Environment Recognition using Line Histogram Method (실내 자율주행 로봇의 구현 및 라인 히스토그램을 이용한 환경인식)

  • Moon, Chan-Woo;Lee, Young-Dae
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.9 no.2
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    • pp.45-50
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    • 2009
  • The environment exploration is an essential process for indoor robots such as clean robot and security robot. Apartment house and office building has common frame structure, but internal arrangement of each room may be slightly different. So, it is more convenient to use a common frame map than to build a new map at every time the arrangement is changed. In this case, it is important to recognize invariant features such as wall, door and window. In this paper, an indoor mobile robot is implemented, and by using the laser scanner data and line segment histogram with respect to segment orientation and distance, an environment exploration method is presented and tested. This robot is fitted with a laser scanner, gyro sensor, ultra sonic sensor and IR sensor, and programed with C language.

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Efficient Synchronization Scheme for Cooperative Communication System over Fading Channel (페이딩 환경에서의 효율적인 협력통신 시스템 동기 알고리즘 연구)

  • Kim, Yoon-Hyun;Kim, Jin-Young
    • Journal of Satellite, Information and Communications
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    • v.5 no.2
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    • pp.64-68
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    • 2010
  • In this paper, we studied the novel synchronization algorithm for cooperative communication system over fading. We research mainly on the decode-and-forward scheme. Also, we inserted spreading sequence in origin data frame to control efficiently data synchronization. In mobile station, inserted spreading sequence in data frame passed through the corelation process. We had decide the delay value of received data through result of correlation process. In simulation, We applied that channel gain of three node had different value in various fading environment. Finally we will be possible to control the received data synchronization using result of corelation value in each node between relay to mobile station and base station to mobile station. The results of this paper can be applicable to the cooperative systems.

Micro-Expression Recognition Base on Optical Flow Features and Improved MobileNetV2

  • Xu, Wei;Zheng, Hao;Yang, Zhongxue;Yang, Yingjie
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.15 no.6
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    • pp.1981-1995
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    • 2021
  • When a person tries to conceal emotions, real emotions will manifest themselves in the form of micro-expressions. Research on facial micro-expression recognition is still extremely challenging in the field of pattern recognition. This is because it is difficult to implement the best feature extraction method to cope with micro-expressions with small changes and short duration. Most methods are based on hand-crafted features to extract subtle facial movements. In this study, we introduce a method that incorporates optical flow and deep learning. First, we take out the onset frame and the apex frame from each video sequence. Then, the motion features between these two frames are extracted using the optical flow method. Finally, the features are inputted into an improved MobileNetV2 model, where SVM is applied to classify expressions. In order to evaluate the effectiveness of the method, we conduct experiments on the public spontaneous micro-expression database CASME II. Under the condition of applying the leave-one-subject-out cross-validation method, the recognition accuracy rate reaches 53.01%, and the F-score reaches 0.5231. The results show that the proposed method can significantly improve the micro-expression recognition performance.

Design and performance analysis of a zero-velocity update Kalman filter for SDINS (SDINS의 영속도 보정 칼만필터 설계)

  • 박흥원;정태호;박찬빈;이장규
    • 제어로봇시스템학회:학술대회논문집
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    • 1988.10a
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    • pp.633-638
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    • 1988
  • In this paper, a zero-velocity update technique to improve navigation accuracy of a SDINS(Strapdown Inertial Navigation System) has been studied. An indirect feedback Kalman filter which includes SDINS error equations based on a quaternion between body-fixed frame and local level navigation frame is employed for processing zero-velocity updates in an on-board navigation filter. Simulation results for land-mobile vehicle show that the zerovelocity update technique make a significant contribution to improving SDINS performance without any external aids.

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A Cooperative ARQ strategy in Ad hoc Cognitive Relays for Mobile Multimedia Communication (이동 멀티미디어 통신을 위한 Ad-hoc Cognitive Relay의 Cooperative ARQ 재전송 기법)

  • An, Mi-Eun;Kang, Hae-Lynn;Kim, Nak-Myeong
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.48 no.3
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    • pp.28-35
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    • 2011
  • Cooperative ARQ scheme is effective for better QoS guarantee for the next generation mobile communication systems where multimedia data transmission highly increases. In this paper, we propose a cooperative ARQ strategy in ad hoc cognitive relays for mobile multimedia communication for supporting instantaneous cooperation in MANET environment. In the proposed strategy, to support real time, delay-sensitive services, whenever a frame is transmitted from the source, each relay actively senses the SINR of the signal transmitted from the source, and determine whether to propose retransmission or not before the destination transmits feedback signal. To minimize the false retransmission decision or needless retransmission, we propose an adaptive sensing threshold optimization algorithm to maintain suboptimal sensing thresholds for each relay. By computer simulation, it is shown that the proposed cooperative ARQ retransmission scheme outperforms the conventional schemes with respect to frame transmission delay and frame loss probability in real time multimedia data transmission system.

Hardware Implementation of Minimized Serial-Divider for Image Frame-Unit Processing in Mobile Phone Camera. (Mobile Phone Camera의 이미지 프레임 단위 처리를 위한 소형화된 Serial-Divider의 하드웨어 구현)

  • Kim, Kyung-Rin;Lee, Sung-Jin;Kim, Hyun-Soo;Kim, Kang-Joo;Kang, Bong-Soon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2007.10a
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    • pp.119-122
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    • 2007
  • In this paper, we propose the method of hardware-design for the division operation of image frame-unit processing in mobile phone camera. Generally, there are two types of the data processing, which are the parallel and serial type. The parallel type makes it possible to process in realtime, but it needs significant hardware size due to many comparators and buffer memories. Compare the serial type with the parallel type, the hardware size of the serial type is smaller than the other because it uses only one comparator, but serial type is not able to process in realtime. To use the hardware resources efficiently, we employ the serial divider since frame-unit operation for image processing does not need realtime process. When compared with both in the same bit size and operating frequency, the hardware size of the serial divider is approximately in the ratio of 13 percentage compared with the parallel divider.

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A Study on MAC Protocol for Packet Data Services in Next-Generation Wireless Networks (차세대 무선망에서 패킷 데이터 서비스를 위한 MAC 프로토콜 연구)

  • 임인택
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.6
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    • pp.1115-1120
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    • 2004
  • In this paper, a CSSMA/AI MAC protocol for data services in packet CDMA network is presented. The main features of this protocol are the code status sensing and code reservation for reducing the packet collision. The base station broadcasts the code status on a frame-by-frame basis just before the beginning of each preamble transmission, and the mobile station transmits a preamble for reserving a randomly selected code based on the received code status. After having transmitted the preamble, the mobile station listens to the downlink of the selected code and waits for the base station reply. If this reply indicates that the code has been correctly acquired, it continues the packet transmission for the rest of the frame. If there are other packets waiting for transmission, the base station broadcasts the status of the code as reserved, and the mobile station transmits a packet on a reserved code for the successive frames.

A Pilot Symbol Insertion Method for SC-FDMA Mobile Communication Systems (SC-FDMA 이동통신 시스템을 위한 파일럿 심벌 삽입 방법)

  • Rim, Min-Joong;Ryu, Chul
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.44 no.6 s.360
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    • pp.48-56
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    • 2007
  • OFDMA (Orthogonal Frequency Division Multiple Access) is widely used as multiple access techniques for next generation mobile communication systems. However, OFDMA has a disadvantage of high peak-to-average power ratio and SC-FDMA (Single-Carrier Frequency Division Multiple Access) was proposed for uplink systems to overcome the drawback. SC-FDMA also has several demerits including degraded performance with high-order modulations or with multiple antenna techniques, and less flexibility in resource allocation and pilot patterns. In order to achieve the best performance over a wide range of environments, each mobile station should select either of OFDMA and SC-FDMA according to the given condition and a pilot structure for SC-FDMA systems should be similar to that of OFDMA to maintain the same frame structure. While conventional SC-FDMA schemes require an entire SC-FDMA symbol or a separate short symbol for pilots, this paper proposes a method which supports the pilots included in SC-FDMA data parts and enables a SC-FDMA frame to hold the same structure as an OFDMA frame.

Application of Network Coding to IEEE 802.16j Mobile Multi-hop Relay Network for Throughput Enhancement

  • Lee, Kyung-Jun;Sung, Won-Jin;Jang, Ju-Wook
    • Journal of Communications and Networks
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    • v.10 no.4
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    • pp.412-421
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    • 2008
  • We observe simultaneous transmission of relay stations (RSs) allowed in current IEEE 802.16j draft standard for multi-hop relay networks may involve severe interference among the RSs, hence leading to throughput degradation. Allowing only 1/3 of the RSs to simultaneously transmit instead of 1/2 RSs as in the current draft standard reduces the interference but results in reduced throughput. To remedy this problem, we devise schemes to incorporate network coding at link-layer level (decode-and-forward) into the simultaneous transmission of RSs. Data movement is rearranged to maximize coding gain. Formula is derived to dictate exact movement of packets traveling between base station (BS) and mobile stations (MSs) via intermediate RSs. The frame structure in the current IEEE 802.16j draft standard does not allow broadcast needed for network coding. We devise a new frame structure which supports the broadcast. A new R-MAP (pointers to the burst data) is introduced to implement the broadcast. Since our new frame structure is used only for BS to RS or RS to RS communication, our schemes retain backward compatibility with legacy MSs based on IEEE 802.16e standard. Simulation based on simple configuration of RSs shows considerable improvement in terms of system throughput and round trip delay. For a 4-hop relay network with 1 BS and 4 RSs with symmetric traffic in uplink (UL) and downlink (DL), throughput is improved by 49% in DL and by 84% in UL traffic compared with IEEE 802.16j draft standard under the assumption that omni-directional antennae are used in BS and RSs.