• Title, Summary, Keyword: hybrid information environments

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Hybrid Algorithm of Space Time and Space Frequency Block Coding Technique using Alternate Time Switch (교번 스위치를 활용한 시공간 및 주파수공간 블록 코딩의 하이브리드 알고리즘)

  • Jung, Hyeok Koo
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.66 no.1
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    • pp.48-52
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    • 2017
  • This paper proposes a hybrid algorithm of space-time block coding and space-frequency block coding using alternate time switch. The traditional alternate time-switched space-time or space-frequency block coding technique for orthogonal frequency division multiplexing system does not provide a good performance with a variety of communication environments. This hybrid algorithm has searched good performance ranges in various environments in view points of mobile speed and doppler frequency. In this paper, we investigate better performance ranges for two algorithms, suggest a hybrid algorithm for dynamically changing communication environments, propose a structure for transmitter and receiver, and show that its performance is better than the traditional algorithm by simulations.

An improved robust hybrid control for uncertain robot manipulators using the stiffness bound of environments (환경의 강성 경계를 이용한 불확실 로봇 시스템의 개선된 견실 하이브리드 제어)

  • 권택준;한명철;하인철
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.259-262
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    • 2001
  • An improved robust hybrid control law is proposed. This law used the separated bounding function and the stiffness bound. It satisfied the performance though we don't know precise information of contact environments. It guarantees the practical stability in sense of Lyapunov. Simulation was performed to validate this law using a four-axis SCARA type robot manipulator.

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Verification of Subsumption Anomalies in Hybrid Knowledge Bases : A Meta-graph Approach (혼합 지식 기반 내 포함 이상의 검증 메타 그라프적 접근)

  • Lee, Sun-Ro
    • Asia pacific journal of information systems
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    • v.7 no.2
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    • pp.163-183
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    • 1997
  • As object models and hybrid knowledge are increasingly used in current information systems development, Is-a structures need to be more formally defined, and subsequently subsumption related anomalies need to be detected with minimal declaration of meta knowledge. This paper extends a metagraph in the hybrid environments and demonstrates its utilities for detecting such anomalies that can occur from semantics and dynamics unique to the hybrid knowledge and data structure.

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A Hybrid Software Defined Networking Architecture for Next-Generation IoTs

  • Lee, Ahyoung;Wang, Xuan;Nguyen, Hieu;Ra, Ilkyeun
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.12 no.2
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    • pp.932-945
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    • 2018
  • Everything in the world is becoming connected and interactive due to the Internet. The future of interactive smart environments such as smart cities, smart industries, or smart farms demand high network bandwidth, high network flexibility, and self-organization systems without costly hardware upgrades, and they provide a sustainable, scalable, and replicable smart environment backbone infrastructure. This paper presents a new Hybrid Software-Defined architecture for integrating Internet-of-Things technologies that are essential technologies for smart environments. It combines a software-defined networking infrastructure and a real-time distributed network framework with an advanced optimization to enable self-configuration, self-management, and self-adaption for providing seamless communication and efficiently managing a vast number of smart heterogeneous devices.

Development of Hybrid Filtering Recommendation System using Context-Information in Mobile Environments (모바일 환경에서 상황정보를 이용한 하이브리드 필터링 추천시스템 설계)

  • Ko, Jung-Min;Nam, Doo-Hee
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.10 no.3
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    • pp.95-100
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    • 2011
  • Due to rapid growth and development of telecommunication information technology, interest has been amplified regarding ubiquitous network computing and user-oriented service. Also, the rapid development of related technologies has been a big spotlight. Smart phone, with features such as a PC with advanced features is a mobile phone. According to environment and infrastructure development, a variety of mobile-based application software to provide various kinds of information and services has been released. However, most of them are provider-driven information systems and aim to provide large amounts of information simply to an unspecified number of users. Therefore, customized or personalized provision of information and service explained earlier for individual users has been hardly come true. According to background and need, this study wants to design and implement recommendations system for personalization and customization in mobile environments. To acquire more accurate recommendation results, recommendation system shall be composed using the Hybrid Filtering. Effective information recommendation according to user's situation by using user's context-information of purpose and location that are available in mobile devices before running the filtering of the information to improve the quality of recommendations.

Hybrid TOA/AOA Cooperative Mobile Localization in 4G Cellular Networks

  • Wu, Shixun;Wang, Shuliang;Xu, Kai;Wang, Honggang
    • IEIE Transactions on Smart Processing and Computing
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    • v.2 no.2
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    • pp.77-85
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    • 2013
  • this study examined hybrid Time of Arrival/Angle of Arrival (TOA/AOA) localization technique in a cellular network. Based on the linearized equations from the TOA and AOA measurements, the weighted least square (WLS) method is proposed to obtain the location estimation of a mobile station (MS) by analyzing the statistical properties of the error vector in Line of Sight (LOS) and Non-line of Sight (NLOS) environments, respectively. Moreover, the precise expression of the Cramer-Rao lower bound (CRLB) for hybrid TOA/AOA measurements in different LOS/NLOS conditions was derived when the LOS error is a Gaussian variable and the NLOS error is an exponential variable. The idea of cooperative localization is proposed based on the additional information from short-range communication among the MSs in fourth generation (4G) cellular networks. Therefore, the proposed hybrid TOA/AOA WLS method can be improved further with the cooperative scheme. The simulation results show that the hybrid TOA/AOA method has better performance than the TOA only method, particularly when the AOA measurements are accurate. Moreover, the performance of the hybrid TOA/AOA method can be improved further by the cooperative scheme.

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A Hybrid Navigation System for Intelligent Wheelchair (지능형 휠체어를 위한 하이브리드 내비게이션 시스템)

  • Ko, Eun-Jeong;Ju, Jin-Sun;Kim, Eun-Yi
    • 한국HCI학회:학술대회논문집
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    • pp.552-557
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    • 2009
  • In this paper, we propose hybrid navigation system, for obstacle detection and avoidance in Intelligent wheelchairs (IWs). To robustly detect obstacles and avoid them on various environments, hybrid navigation system combines both range-sensor and camera information. For this, 10 range-sensors (2 ultrasonic and 8 infra-red sensors) and CCD camera are used. Through processing the informations obtained from those sensors, our system can detect obstacles with various sizes and shapes, and then avoid them. To assess the effectiveness of the proposed hybrid navigation system, it was tested on complex environments including various obstacles, then the results showed the potential of our system as mobility aids for disabled people.

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Performance Analysis of an Adaptive Hybrid Search Code Acquisition Algorithm for DS-CDMA Systems (DS-CDMA 시스템을 위한 적응 혼합 검색형 동기획득 알고리즘의 성능 분석)

  • Park Hyung rae;Yang Yeon sil
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.3C
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    • pp.83-91
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    • 2005
  • We analyze the performance of an adaptive hybrid search code acquisition algorithm for direct-sequence code division multiple access (DS-CDMA) systems under slowly-moving mobile environments. The code acquisition algorithm is designed to provide the desired feature of constant false alarm rate (CFAR) to cope with nonstationarity of the interference in CDMA forward links. An analytical expression for the mean acquisition time is first derived and the probabilities of detection, miss, and false alarm are then obtained for frequency-selective Rayleigh fading environments. The fading envelope of a received signal is assumed to be constant over the duration of post-detection integration (PDI), considering slow fading environments. Finally, the performance of the designed code acquisition algorithm shall be evaluated numerically to examine the effect of some design parameters such as the sub-window size, size of the PDI, decision threshold, and so on, considering cdma2000 environments.

Design and Performance Evaluation of Data Models for the XML Document Management (XML 문서관리를 위한 데이터 모델 설계 및 성능평가)

  • 유재수;손충범;조혜영
    • Journal of Internet Computing and Services
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    • v.2 no.5
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    • pp.59-70
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    • 2001
  • Recently, in various fields XML has been become a standard for information exchange in internet. Therefore, the researches on data modeling for storing and fetching the XML documents have been made actively. However, existing researches have weak points that they can support neither versioning nor fast fetching of documents while changing documents in dynamic environments. In this paper, we propose four kinds of hybrid data modeling schemes that combine fragmentation model and nonfragmentation model. Our data modeling schemes are suitable to dynamic environments. We also present guidelines that our hybrid data modeling schemes can be used for various applications. We shaw through various experiments that our hybrid schemes partially outperforms the existing modeling schemes in terms of insertion time, storage space and retrieval time.

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