• Title/Summary/Keyword: Cognitive Engineering

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Enhanced FCME Thresholding for Wavelet-Based Cognitive UWB over Fading Channels

  • Hosseini, Haleh;Fisal, Norsheila;Syed-Yusof, Sharifah Kamilah
    • ETRI Journal
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    • v.33 no.6
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    • pp.961-964
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    • 2011
  • The cognitive ultra-wideband (UWB) network detects interfering narrowband systems and adapts its configuration accordingly. An inherently adaptive and flexible candidate for cognitive UWB transmission is the wavelet packet multicarrier modulation (WPMCM). In this letter, we use an enhanced forward consecutive mean excision thresholding algorithm to tackle the noise uncertainty in the wavelet-based sensing of WPMCM systems, and mathematical analysis is performed for primary user channel fading. As a benchmark, we compare the proposed system with a conventional fast Fourier transformation-based system, and performance investigation proves significant improvements when primary and secondary links are subjected to multipath fading and noise.

Cognitive Radio Based Spectrum Sharing: Evaluating Channel Availability via Traffic Pattern Prediction

  • Li, Xiukui;Zekavat, Seyed A. (Reza)
    • Journal of Communications and Networks
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    • v.11 no.2
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    • pp.104-114
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    • 2009
  • In this paper, a technique is proposed that enables secondary users to evaluate channel availability in cognitive radio networks. Here, secondary users estimate the utilization of channels via predicting the traffic pattern of primary user, and select a proper channel for radio transmission. The proposed technique reduces the channel switching rate of secondary users (the rate of switching from one channel to another) and the interference on primary users, while maintaining a reasonable call blocking rate of secondary users.

A Study on the Cognitive Process of Supervisory control in Human-Computer Interaction (인간-컴퓨터 작업에서 감시체계의 상황인지과정에 관한 연구)

  • 오영진;이근희
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.16 no.27
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    • pp.105-111
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    • 1993
  • Human works shift its roll from physical condition to the system supervisory control task In this paper safety-presentation configuration is discussed instead of well-known fault-warning configuration. Of paticular interest was the personal factor which include the cognitive process. Through a performance between each person information processing(d') and decision process($\beta$) was pointed out to explain the sensitivity of personal cognitive process. Impact of uncertainty effect the supervisor having doubt situations. These facts are released by the use of flat fuzzy number of $\beta$ and its learning rate R.

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Power Control for Cognitive Radio Networks: Monotonic Optimization Approach

  • Nguyen, Tran Quang;Hong, Choong-Seon
    • Proceedings of the Korean Information Science Society Conference
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    • 2011.06a
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    • pp.344-347
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    • 2011
  • In this paper, we propose the power control problem for cognitive radio networks (CRNs) that maximizes the total utility of the secondary users (SUs). We use the interference temperature constraints to protect the primary users (PUs). The utility functions of SUs can be any increasing functions. We formulate the power control problem as monotonic optimization that can be solved in centralization to achieve the global optimum.

An Approach to maximize throughput for Energy Efficient Cognitive Radio Networks

  • Ghosh, Jyotirmoy;Koo, Insoo
    • International Journal of Advanced Culture Technology
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    • v.1 no.2
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    • pp.18-23
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    • 2013
  • In this paper, we consider the problem of designing optimal sensing time and the minimization of energy consumption in the Cognitive radio Network. Trade-off between throughput and the sensing time are observed, and the equations are derived for the optimal choice of design variables. In this paper, we also look at the optimization problem involving all the design parameters together. The advantages of the proposed scheme for the spectrum sensing and access process are shown through simulation.

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Rendezvous in Cognitive Radio Networks without Common Control Channel

  • Htike, Zaw;Hong, Choong-Seon
    • Proceedings of the Korean Information Science Society Conference
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    • 2011.06d
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    • pp.230-231
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    • 2011
  • In this paper, we propose a rendezvous mechanism for cognitive radio networks. In this mechanism, no prior knowledge of wireless nodes is required and it is totally distributed. Node can simply choose one of two strategies to rendezvous with its neighbors. The main benefit of this mechanism is eliminating the use of common control channel and centralized controller.

Cognitive Modeling of Unusual Association with Declarative Knowledge by Positive Affect (긍정적 감정에 따른 선언적 지식에 관한 비전형적 연상 과정에 대한 인지모델링)

  • Park, Sung-Jin;Myung, Ro-Hae
    • Journal of Korean Institute of Industrial Engineers
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    • v.41 no.1
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    • pp.43-49
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    • 2015
  • The aim of this study was to model unusual association with declarative knowledge by positive affect using ACT-R cognitive architecture. Existing research related with cognitive modeling tends to pay a lot of attention to strong and negative cognitive moderator. Mild positive affect, however, has far-reaching effects on problem solving and decision making. Typically, subjects with positive affect were more likely to respond to unusual associates in a word association task than subjects with neutral affect. In this study, a cognitive model using ACT-R cognitive architecture was developed to show the effect of positive affect on the cognitive organization related with memory. First, we organized the memory structure of stimulus word 'palm' based on published results in a word association task. Then, we decreased an ACT-R parameter that reflects the amount of weighting given to the dissimilarity between the stimulus word and the associate word to represent reorganized memory structure of the model by positive affect. As a result, no significant associate probability difference between model prediction and existing empirical data was found. The ACT-R cognitive architecture could be used to model the effect of positive affect on the unusual association by decreasing (manipulating) the weight of the dissimilarity. This study is useful in conducting model-based evaluation of the effects of positive affect in complex tasks involving memory, such as creative problem solving.

Protection of Digital TV from Cognitive Radio Interference

  • Yoon, Young-Keun;Hong, Heon-Jin;Choi, Ik-Guen
    • ETRI Journal
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    • v.29 no.3
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    • pp.393-395
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    • 2007
  • Analytic modeling and computational simulation for the protection of DTV from cognitive radio interference are performed. Protection is achieved by using the protection ratio, which is derived through system modeling and its analysis. On the frequency coordination between digital TV and cognitive radio, an analysis in a co-channel environment, in a rural area in Korea, is performed.

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The Impact of Landscape Type on Urban Office Workers' Stress and Cognitive Performance - Comparison between Natural and Urban Landscape - (경관유형이 도시사무직 근로자의 스트레스와 인지수행에 미치는 영향 -자연경관과 도시경관과의 비교를 중심으로-)

  • Yi Young-Kyoung;Yi Pyong-In
    • Journal of the Korean Institute of Landscape Architecture
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    • v.33 no.6 s.113
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    • pp.1-11
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    • 2006
  • The purpose of this study was to investigate the influence of natural landscapes in the context of work environments. The study examined the impact of natural landscapes on urban office workers' stress reduction and cognitive performance, using physiological, psychological, and cognitive measures. One-hundred-twenty urban office workers participated in the experiments. The physiological measures used were GSR (galvanic skin response) and IBI (interbeat interval), and the psychological measure was ZIPERS (Zucherman Inventory of Personal Reactions). Cognitive performance was measured using a mental arithmetic test that had been developed by a pretest. The results from the physiological, psychological, and cognitive measures converged to indicate that the natural landscape had more beneficial effects in relieving both psychological and physiological stress and in enhancing cognitive performance of the of office workers than the city landscape. The results suggest wide applications in the fields of workers' well-being and landscape research. First, the results can provide reliable information for promoting natural landscaping in work places in order to relieve worker stress and enhance cognitive performance. Second, the results provide an example for future empirical landscape research using multiple measurements, such as psychological, physiological, and cognitive tests. Third, they can foster experimental research to investigate the relationship between stress reduction and natural landscapes.