Due to the usable frequency becomes more and more crowed, dynamic spectrum access （DSA） is a new hope to solve this problem. However, DSA in China requires a quantitative analysis of the current spectrum utilization...Due to the usable frequency becomes more and more crowed, dynamic spectrum access （DSA） is a new hope to solve this problem. However, DSA in China requires a quantitative analysis of the current spectrum utilization in frequency, temporal and spatial domains. In order to free the precious spectrum, spectrum regulation organizations must have a clear, detailed, up-to-date understanding of where, how and by whom spectrum is currently being used--such data is essential to sound policy decisions in the context of cognitive radio （CR）. In this paper, a concurrent spectrum occupancy measurement in south China was conducted to evaluate the practical spectrum occupancy with a digital wideband receiver covering from 20 MHz to 3 GHz. We also propose systemic spectrum measurement methodology, matrix format data storage, duty cycle （DC） evaluation metric and data mining process which can be a guideline for other researchers when they conduct the similar experiments. Quantitative analysis and characterization of the 4 different measurement locations are evaluated to promote the popularization of CR application in China. And a uniform Beta distribution channel occupancy model is also validated using real-scene measurement data. The experimental results demonstrate that there is a significant scope for license-exemption use of the released spectrum using CR technology.展开更多
<span><b><span style="font-family:"">Aim: </span></b></span><span><span><span style="font-family:"">Beneficial effects of<b> &l...<span><b><span style="font-family:"">Aim: </span></b></span><span><span><span style="font-family:"">Beneficial effects of<b> </b>virgin coconut oil (VCO) consumption to improve cognition <span>in menopausal females<sup> </sup>remain inconclusive. This study examined the effect of VCO supplementation in aging cycling and non-cycling rodents to assess its impact on cognition. <b>Methods:</b> Sprague-Dawley rats (10</span></span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:"">-</span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:"">18 months) were randomly assigned to a supplemented VCO group (SVCO) that received oral doses of 1.42 mL/kg/day VCO (n = 10) and a non-supplemented (</span></span></span><span><span><span style="font-family:"">NVCO) group (n = 10). Their performance in a biased Y-maze discriminative learning paradigm was assessed over a 16-week period. Rats were initially allowed 3 minutes to explore the maze (</span></span></span><span><span><span style="font-family:""><i></span></span></span><span><span><i><span style="font-family:"">habituated</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><span style="font-family:"">) and subsequently </span></span></span><span><span><span style="font-family:""><i></span></span></span><span><span><i><span style="font-family:"">pre-trained</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><i><span style="font-family:""> </span></i></span></span><span><span><span style="font-family:"">in the non-preferred, white chamber to associate the presentation of a tone with a treat (reward). </span></span></span><span><span><span style="font-family:""><i></span></span></span><span><span><i><span style="font-family:"">Training</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><spa展开更多
Cognitive cycle is a basic procedure of mental activities in cognitive level. Human cognition consists of cascading cycles of recurring brain events. This paper presents a cognitive cycle for the mind model CAM (Consc...Cognitive cycle is a basic procedure of mental activities in cognitive level. Human cognition consists of cascading cycles of recurring brain events. This paper presents a cognitive cycle for the mind model CAM (Consciousness And Memory). Each cognitive cycle perceives the current situation, through motivation phase with reference to ongoing goals, and then composes internal or external action streams to reach the goals in response. We use dynamic description logic which is an extended description logic with action to formalize descriptions and algorithms of cognitive cycle. Two important algorithms, including hierarchical goal and action composition, is proposed in the paper.展开更多
Cognitive radio devices can utilize the licensed channels in an opportunistic manner to solve the spectrum scarcity issue occurring in the unlicensed spectrum.However,these cognitive radio devices(secondary users)are ...Cognitive radio devices can utilize the licensed channels in an opportunistic manner to solve the spectrum scarcity issue occurring in the unlicensed spectrum.However,these cognitive radio devices(secondary users)are greatly affected by the original users(primary users)of licensed channels.Cognitive users have to adjust operation parameters frequently to adapt to the dynamic network environment,which causes extra energy consumption.Energy consumption can be reduced by predicting the future activity of primary users.However,the traditional prediction-based algorithms require large historical data to achieve a satisfying precision accuracy which will consume a lot of time and memory space.Moreover,many of these schemes lack methods to deal with the very busy network environments.In this paper,one semi-supervised learning algorithm,i.e.,tri-training,has been employed to investigate the prediction of primary activity.Based on the prediction results of tri-training,a duty-cycle mechanism and an intermediate node selection approach are proposed to improve the energy efficiency.Simulation results show the effectiveness of the proposed algorithm.展开更多
Rendezvous is a blind process establishing a communication link on a common channel between a pair of nodes in cognitive radio networks. We propose two guaranteed rendezvous algorithms for cognitive radio networks und...Rendezvous is a blind process establishing a communication link on a common channel between a pair of nodes in cognitive radio networks. We propose two guaranteed rendezvous algorithms for cognitive radio networks under both single-radio and multi-radio scenarios with an asynchronous setting. For single-radio scenario, each cycle length is a prime number associated with a channel hopping sequence.The rendezvous can be guaranteed as long as the IDs of the two nodes are different. For multi-radio scenario, we propose a cycle length and rotation based rendezvous algorithm. Each node generates a channel hopping sequence with only one cycle length. Then these radios of each nodes rotate on the generated sequence with different rotation numbers at each hopping cycle. The rendezvous between two nodes is guaranteed as long as they have different cycle lengths or the same cycle length with different number of rotations. We conduct simulations on three metrics and the results show that the proposed algorithms outperform the existing ones.展开更多
Cognitive radio(CR) can bring about remarkable improvement in spectrum utilization.Different cognition cycles have been proposed in recent years.However,most of the existing works only emphasize functional or operatio...Cognitive radio(CR) can bring about remarkable improvement in spectrum utilization.Different cognition cycles have been proposed in recent years.However,most of the existing works only emphasize functional or operational aspects of cognition cycle,regardless of other indispensable aspects and the connection between them.To deal with the emerging situation of "data rich,information vague,knowledge poor" in cognitive radio networks(CRNs),we propose the hierarchical cognition cycle(HCC) as a new transdisciplinary research field in this paper.HCC investigates a fundamental problem,which is how to manage available resources in the complex environment to meet various demands in CRN.A comprehensive theoretical framework of HCC is established in terms of the core,the essence loop,the function loop,the operation loop,and the external loop of HCC.The reduction of uncertainty in CRN is studied and several new metrics in HCC are defined.Furthermore,a few research challenges ahead are presented as well.展开更多
基金sponsored by the National Basic Research Program of China (2011CB302900)Postgraduate Innovation Fund of R&S-BUPT 2011+1 种基金National Key Technology R&D Program of China(2012ZX03003006)Shenzhen Bureau of Trade and Industry(JC200903170458A, JC201006010739A)
文摘Due to the usable frequency becomes more and more crowed, dynamic spectrum access （DSA） is a new hope to solve this problem. However, DSA in China requires a quantitative analysis of the current spectrum utilization in frequency, temporal and spatial domains. In order to free the precious spectrum, spectrum regulation organizations must have a clear, detailed, up-to-date understanding of where, how and by whom spectrum is currently being used--such data is essential to sound policy decisions in the context of cognitive radio （CR）. In this paper, a concurrent spectrum occupancy measurement in south China was conducted to evaluate the practical spectrum occupancy with a digital wideband receiver covering from 20 MHz to 3 GHz. We also propose systemic spectrum measurement methodology, matrix format data storage, duty cycle （DC） evaluation metric and data mining process which can be a guideline for other researchers when they conduct the similar experiments. Quantitative analysis and characterization of the 4 different measurement locations are evaluated to promote the popularization of CR application in China. And a uniform Beta distribution channel occupancy model is also validated using real-scene measurement data. The experimental results demonstrate that there is a significant scope for license-exemption use of the released spectrum using CR technology.
文摘<span><b><span style="font-family:"">Aim: </span></b></span><span><span><span style="font-family:"">Beneficial effects of<b> </b>virgin coconut oil (VCO) consumption to improve cognition <span>in menopausal females<sup> </sup>remain inconclusive. This study examined the effect of VCO supplementation in aging cycling and non-cycling rodents to assess its impact on cognition. <b>Methods:</b> Sprague-Dawley rats (10</span></span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:"">-</span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:"">18 months) were randomly assigned to a supplemented VCO group (SVCO) that received oral doses of 1.42 mL/kg/day VCO (n = 10) and a non-supplemented (</span></span></span><span><span><span style="font-family:"">NVCO) group (n = 10). Their performance in a biased Y-maze discriminative learning paradigm was assessed over a 16-week period. Rats were initially allowed 3 minutes to explore the maze (</span></span></span><span><span><span style="font-family:""><i></span></span></span><span><span><i><span style="font-family:"">habituated</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><span style="font-family:"">) and subsequently </span></span></span><span><span><span style="font-family:""><i></span></span></span><span><span><i><span style="font-family:"">pre-trained</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><i><span style="font-family:""> </span></i></span></span><span><span><span style="font-family:"">in the non-preferred, white chamber to associate the presentation of a tone with a treat (reward). </span></span></span><span><span><span style="font-family:""><i></span></span></span><span><span><i><span style="font-family:"">Training</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><spa
文摘Cognitive cycle is a basic procedure of mental activities in cognitive level. Human cognition consists of cascading cycles of recurring brain events. This paper presents a cognitive cycle for the mind model CAM (Consciousness And Memory). Each cognitive cycle perceives the current situation, through motivation phase with reference to ongoing goals, and then composes internal or external action streams to reach the goals in response. We use dynamic description logic which is an extended description logic with action to formalize descriptions and algorithms of cognitive cycle. Two important algorithms, including hierarchical goal and action composition, is proposed in the paper.
基金This work was partially supported by the National Natural Science Foundation of China(Grant Nos.11761074,61972207,61902041)the Natural Science Foundation of Jilin Province of China(Grant No.2020122336JC)Project of Jilin Science and Technology Development for Leading Talent of Science and Technology Innovation in Middle and Young and Team Project(No.20200301053RQ)and the Project through the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institution.
文摘Cognitive radio devices can utilize the licensed channels in an opportunistic manner to solve the spectrum scarcity issue occurring in the unlicensed spectrum.However,these cognitive radio devices(secondary users)are greatly affected by the original users(primary users)of licensed channels.Cognitive users have to adjust operation parameters frequently to adapt to the dynamic network environment,which causes extra energy consumption.Energy consumption can be reduced by predicting the future activity of primary users.However,the traditional prediction-based algorithms require large historical data to achieve a satisfying precision accuracy which will consume a lot of time and memory space.Moreover,many of these schemes lack methods to deal with the very busy network environments.In this paper,one semi-supervised learning algorithm,i.e.,tri-training,has been employed to investigate the prediction of primary activity.Based on the prediction results of tri-training,a duty-cycle mechanism and an intermediate node selection approach are proposed to improve the energy efficiency.Simulation results show the effectiveness of the proposed algorithm.
基金supported in part by NSF under the grant CNS-1526152
文摘Rendezvous is a blind process establishing a communication link on a common channel between a pair of nodes in cognitive radio networks. We propose two guaranteed rendezvous algorithms for cognitive radio networks under both single-radio and multi-radio scenarios with an asynchronous setting. For single-radio scenario, each cycle length is a prime number associated with a channel hopping sequence.The rendezvous can be guaranteed as long as the IDs of the two nodes are different. For multi-radio scenario, we propose a cycle length and rotation based rendezvous algorithm. Each node generates a channel hopping sequence with only one cycle length. Then these radios of each nodes rotate on the generated sequence with different rotation numbers at each hopping cycle. The rendezvous between two nodes is guaranteed as long as they have different cycle lengths or the same cycle length with different number of rotations. We conduct simulations on three metrics and the results show that the proposed algorithms outperform the existing ones.
基金supported by the National Key Basic Research Program of China(973 Program) under Grant No.2009CB320400the National Natural Science Foundation of China under Grants No.60932002,61172062,61301160the Natural Science Foundation of Jiangsu,China under Grant No.BK2011116
文摘Cognitive radio(CR) can bring about remarkable improvement in spectrum utilization.Different cognition cycles have been proposed in recent years.However,most of the existing works only emphasize functional or operational aspects of cognition cycle,regardless of other indispensable aspects and the connection between them.To deal with the emerging situation of "data rich,information vague,knowledge poor" in cognitive radio networks(CRNs),we propose the hierarchical cognition cycle(HCC) as a new transdisciplinary research field in this paper.HCC investigates a fundamental problem,which is how to manage available resources in the complex environment to meet various demands in CRN.A comprehensive theoretical framework of HCC is established in terms of the core,the essence loop,the function loop,the operation loop,and the external loop of HCC.The reduction of uncertainty in CRN is studied and several new metrics in HCC are defined.Furthermore,a few research challenges ahead are presented as well.
