• Title/Summary/Keyword: 효율성 향상

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A Study on the Development of real time monitoring system data model in Steel Structural Construction (철골공사에서의 실시간 모니터링 시스템 데이터 모델 개발에 관한 연구)

  • Son, Chi-Soo;Kim, Kyung-Hwan;Lee, Yoon-Sun;Kim, Jae-Jun
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2007.11a
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    • pp.823-826
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    • 2007
  • In the construction project, the efforts to use IT for efficient management and improvement of productivity is gradually increasing. For instance, the cite management model with 3D CAD and RFID shows one of efforts this model define and systematize a variety of data occurred each work unit(design, material and process management information, etc). However, so far, there has been the problem monitoring the site due to the an inaccurate data and low-practice which people should input in manual. In this paper, we would like to establish the data for real time monitoring system with data inputting automatically from RTPM system and the site, and analyze the relationship between tables consist of similar data through RED Diagram.

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A Fast Motion Estimation using Characteristics of Wavelet Coefiicients (웨이블릿 계수 특성을 이용한 고속 움직임 추정 기법)

  • Sun, Dong-Woo;Bae, Jin-Woo;Yoo, Ji-Sang
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.4C
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    • pp.397-405
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    • 2003
  • In this paper, we propose an efficient motion estimation algorithm which can reduce computational complexity by using characteristics of wavelet coefficient in each subband while keeping about the same image quality as in using MRME(multiresolution motion estimation). In general, because of the high similarity between consecutive frames, we first decide whether the motion exists or not by just comparing MAD(mean absolute difference) between blocks with threshold in the lowest subbands of consecutive two frames. If it turns out that there is no motion in the lowest subband, we can also decide no motion exists in the higher subband. This is due to the characteristics of wavelet transform. Conversely, if we find any motion in the lowest subband, we can reduce computational complexity by estimating high subband motion vectors selectively according to the amount of computational complexity by estimating high subband motion vectors selectively according to the amount of energy in that subband. Experimental results are shown that algorithm suggested in this paper maintains about the same PSNR as MRME. However, the processing time was reduced about 30-50% compared with the MRME.

Resource Allocation and Power Control for Device-to-Device Communication in LTE-Advanced Based on User Area Information (LTE-Advanced에서 단말간 직접 통신을 위한 영역 정보 기반 자원할당 및 전력 제어 기법)

  • Li, Xiang;Shin, Oh-Soon;Shin, Yoan
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.1
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    • pp.32-42
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    • 2015
  • In this paper, we considered the scenario that one cellular link and muti-D2D links share the same frequency resource which can improve the spectrum efficiency during uplink communication in LTE (Long Term Evolution)-Advanced network. In order to reduce the interference caused to the D2D users, we set DME (Discovery and Management Entity) which can send the area information to eNB(evolved Node B). We proposed a resource allocation scheme by using these assistant devices to reduce the interference that CUE (Cellular User Equipment) causes to DUE Rx (D2D UE Receiver). Basing on the area information, in order to mitigate the interference among the D2D pairs which share the same frequency resource, a power control scheme has been proposed. The simulation results prove that by using the DMEs, the proposed schemes improve the stability of D2D communication and bring the highest performance of the communication system when comparing to the other different schemes.

PAPR Reduction Technique and BER Performance Improvement in OFDM-based Wireless Visible Light Communication (OFDM을 사용하는 무선 가시 광통신에서의 PAPR 저감 기법과 BER성능 개선)

  • Ryu, Sang-Burm;Ryu, Heung-Gyoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.3A
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    • pp.189-197
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    • 2011
  • OFDM systems are much studied for the recent high speed wireless optical communication system. OFDM system has basically high PAPR and ICI easily generated because of non-linearity and RF impairments. In the wireless optical communication system, optical output power driven by current of LED is not linear so that transmission signals are distorted. Therefore, research about reception performance of this nonlinear optical output emitted by non-linear LED transfer function and OFDM signal has been conducted. Nonlinear effect of LED is different from nonlinear effect of OFDM system in the conventional radio communication system, which degrades the BER performance. In this paper, we apply non-linear transfer function of recently studied LED into OFDM system. So, for reducing the PAPR and suppressing the ICI in frequency domain of receiver, we suggest a new PAPR reduction technique to reduce non-linear distortion of LED and an adaptive ICI suppression algorithm so that BER performance may be improved. Also, the proposed method is verified through simulation results.

Development of Clustering-Based Multi-Channel MAC Protocol to Improve Efficiency of Network in VANET (차량 환경에서 통신 효율 향상을 위한 클러스터링 기반의 멀티채널 매체접속제어 프로토콜 개발)

  • Jung, Sung-Dae;Lee, Seung-Jin;Lee, Sang-Sun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.5B
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    • pp.463-468
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    • 2009
  • In VANET(Vheicle Ad hoc Network), the researches based on the wireless LAN are conducting and the method based on 802.11a is being adapted in IEEE 802.11p WAVE(Wireless Access in Vehicular Environments). However, wireless LAN which uses a single channel in a competition can cause transmission delays because of a frequent collision and a use of CSMA/CA to avoid competition in VANET requiring a fast access. In this paper, we designed CMMP (Clustering based Multi-channel MAC protocol) adequate to VANET and then confirmed the appropriate channel conditions in a V2V communication on the basis of this protocol. The simulation results showed that a packet collision and a transmission delay by the use of an existing single channel based on the contention decreased more than 60% by CMMP.

Delay-Aware Packet Scheduling (DAPS) Algorithm in 3GPP LTE System (LTE 시스템에서 지연에 대한 QoS 보장을 위한 하향링크 패킷 스케줄링 알고리즘)

  • Choi, Bum-Gon;Chung, Min-Young;Lee, Hye-Kyung;Kim, Tai-Suk;Kang, Jee-Woong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.5B
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    • pp.498-508
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    • 2009
  • In wireless mobile environments, large bandwidth and high QoS (Quality of Service) are recently required to support the increased demands for multimedia services. LTE (Long Term Evolution) is one of the promising solutions for the next generation broadband wireless access systems. To efficiently use downlink resource and effectively support QoS, packet scheduling algorithm is one of the important features in LTE system. In this paper, we proposed DAPS (Delay-Aware Packet Scheduling) algorithm to consider QoS requirements of delays for various traffic classes as well as channel condition and fairness. To reflect delay experiences at scheduling instance, DAPS observes how queue waiting time of packet is closed to maximum allowable delay. The simulation results show that the DAPS algorithm yields better performance for delay experience by increasing the number of transmitted packets with satisfying the required delay time compared with existing scheduling algorithms.

MAC Scheduling Scheme for VoIP Traffic Service in 3G LTE (3G LTE VoIP 트래픽 서비스를 위한 MAC 스케줄링 기법)

  • Jun, Kyung-Koo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.6A
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    • pp.558-564
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    • 2007
  • 3G Long Term Evolution, which aims for various mobile multimedia service provision by enhanced wireless interface, proposes VoIP-based voice service through a Packet Switching (PS) domain. As delay and loss-sensitive VoIP traffic flows through the PS domain, more challenging technical difficulties are expected than in Circuit Switching (CS) domain based VoIP services. Moreover, since 3G LTE, which adopts the OFDM as its physical layer, introduces Physical Resource Block (PRB) as a unit for transmission resources, new types of resource management schemes are needed. This paper proposes a PRB scheduling algorithm of MAC layer for VoIP service in 3G LTE and shows the simulation results. The proposed algorithm has two key parts; dynamic activation of VoIP priority mode to satisfy VoIP QoS requirements and adaptive adjustment of the priority mode duration in order to minimize the degradation of resource utilization.

FBLA (Flexible Block-wise Loading Algorithm) for Effective Resource Allocation and Reduction of the Uplink Feedback Information in OFDMA System (OFDMA 시스템에서 효율적인 자원할당과 상향링크 궤환 정보 축소를 위한 FBL (Flexible Block-wise Loading) 알고리즘)

  • Sun, Tae-Hyung;Ko, Sang-Jun;Chang, Kyung-Hi;Hwang, Sung-Hyun;Song, Myung-Sun;Kim, Chang-Joo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.6A
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    • pp.608-616
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    • 2007
  • OFDM Systems for multi-user use adaptive modulation and ending (AMC) which is a method that selects suitable modulation order and code rate depending on channel state of each user. Using AMC, OFDM system can provide high quality and reliable communication. Base station using AMC scheme requires downlink channel information of each terminal to operate optimality. However, under practical system environment, it is unsuitable to transmit all channel information because uplink bandwidth of the system is limited. In this paper, we propose a flexible block-wise loading (FBL) algorithm combined with a novel CQI feedback scheme with reduced number of required bits to optimize the performance of AMC system. Proposed algorithm allocates sub-carrier groups dynamically to improve the sector throughput and outage probability performance.

Adaptive Intra Fast Algorithm of H.264 for Video Surveillance (보안 영상 시스템에 적합한 H.264의 적응적 인트라 고속 알고리즘)

  • Jang, Ki-Young;Kim, Eung-Tae
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.12C
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    • pp.1055-1061
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    • 2008
  • H.264 is the prominent video coding standard in various applications such as real-time streaming and digital multimedia broadcasting, since it provides enhanced compression performance, error resilience tools, and network adaptation. Compression efficiency of H.264 has been improved, however, it requires more computing and memory access than traditional methods. In this paper we proposed adaptive intra fast algorithm for real-time video surveillance system reducing the encoding complexity of H264/A VC. For this aim, temporal interrelationship between macroblock in the previous and the current frame is used to decide the encoding mode of macroblock fast. As a result, though video quality was deteriorated a little, less than 0.04dB, and bit rate was somewhat increased in suggested method, however, proposed method improved encoding time significantly and, in particular, encoding time of an image with little changes of neighboring background such as surveillance video was more shortened than traditional methods.

A Synchronous Digital Duplexing Technique for Wireless Transmission in Indoor Environments (옥내 환경에서 무선 전송을 위한 동기식 디지털 이중화 방식)

  • Park, Chang-Hwan;Ko, Yo-Han;Park, Kyung-Won;Jeon, Won-Gi;Paik, Jong-Ho;Lee, Seok-Pil;Cho, Yong-Soo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.12C
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    • pp.971-982
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    • 2008
  • In this paper, we propose a new digital duplexing scheme, called SDD(Synchronous Digital Duplexing), which can increase data efficiency and flexibility of resource by transmitting uplink signal and downlink signal simultaneously. In order to transmit uplink data and downlink data simultaneously, the proposed SDD obtains mutual informations between AP(access point) and each SSs(subscriber station), SS and other SSs by mutual ranging procedure. These informations are used for selection of transmission time, decision of CS insertion, setting of CS length, and FFT duration resetting, etc. It is shown that the proposed SDD is appropriate for duplexing scheme in indoor environments over the conventional TDD(Time Division Duplexing) and FDD(Frequency Division Duplexing).