期刊文献+
共找到118,259篇文章
< 1 2 250 >
每页显示 20 50 100
Impact of community public health care on treatment effect,health cognition,and self-management in patients with type 2 diabetes
1
作者 Hong Shi Chun Liu Hong-Yan Luo 《World Journal of Clinical Cases》 SCIE 2025年第5期22-29,共8页
BACKGROUND At present,China has become the country with the largest number of individuals with diabetes mellitus(DM)in the world,with a total of approximately 140 million patients,the majority of whom have type 2 DM(T... BACKGROUND At present,China has become the country with the largest number of individuals with diabetes mellitus(DM)in the world,with a total of approximately 140 million patients,the majority of whom have type 2 DM(T2DM).Based on conven-tional nursing methods,community home care has important clinical significance in controlling blood sugar and disease progression.AIM To explore the impact of community public health nursing on treatment effect,health cognition,and self-management in patients with T2DM.METHODS One hundred patients with T2DM were selected as the research subjects.The patients were divided into either a conventional nursing group or community nursing(CN)group using the random number table method.The conventional nursing group(50 cases)received routine care,while the CN group(50 cases)received community public health care in addition to routine care as that for the conventional nursing group.The rate of excellent and good blood glucose control,fasting blood glucose before and after care,2-h postprandial blood glucose,health cognition,and self-management ability,and patient satisfaction were compared between the two groups.RESULTS The CN group had a higher rate of excellent blood sugar control than the conventional nursing group(88%vs 70%,P<0.05).Before care,there was no significant difference in fasting blood glucose or 2-h postprandial blood glucose between the two groups of patients(P>0.05).After nursing,fasting blood glucose and 2-h postprandial blood glucose were reduced to varying degrees in both groups,and both blood glucose levels in the CN group were lower than those of the conventional nursing group(P<0.05).Compared with the scores before care,the cognitive level score for diabetes and self-management ability score improved after care in both groups.The cognitive level and self-management ability of patients in the CN group were higher than those of the conventional nursing group(P<0.05).The overall satisfaction of the CN group was better than that of the conventional nursing group(98%vs 86%,P<0.05).CONCLUSION Community public health care based on conventional care of T2DM can achieve better blood sugar control,and improve patients’health cognitive level and self-management ability. 展开更多
关键词 Community public health care Type 2 diabetes Blood sugar control Self-management ability cognition level
在线阅读 下载PDF
Serum homocysteine showed potential association with cognition and abnormal gut microbiome in major depressive disorder
2
作者 Chen-Chen Xu Wen-Xuan Zhao +6 位作者 Yu Sheng Ya-Jun Yun Ting Ma Ning Fan Jia-Qi Song Jun Wang Qi Zhang 《World Journal of Psychiatry》 2025年第3期234-248,共15页
BACKGROUND Cognitive impairment is one of the common clinical manifestations of depression,causing negative distress to patients.Elevated homocysteine(Hcy)concentrations and gut microbiome dysfunction may be observed ... BACKGROUND Cognitive impairment is one of the common clinical manifestations of depression,causing negative distress to patients.Elevated homocysteine(Hcy)concentrations and gut microbiome dysfunction may be observed in patients with depression.AIM To investigate the relationship between Hcy,microbiome,and cognition in depressive patients.METHODS We recruited 67 patients with major depressive disorder(MDD)(MDD group)and 94 healthy controls(HCs)individuals(HCs group).Serum Hcy levels were determined using the enzyme circulation method.16s rRNA sequencing was used to classify and identify the fecal bacteria.17 Hamilton depression rating scale and MATRICS consensus cognitive battery were used to evaluate mood states and cognition in patients with MDD. Correlation analysis was performed to explore the correlation between fecal flora,Hcy, and depressive cognitive function.RESULTSElevated serum levels of Hcy were seen in patients with MDD compared to healthy individuals. Patients withMDD indicated significant decreases in cognitive scores (P < 0.001) in six modules: Speed of processing, workingmemory, visual learning, reasoning and problem-solving, social cognition, and total scores. Hcy levels showed anegative correlation with processing speed, social cognition, and total MDD scores (P < 0.05). Hcy was alsosignificantly negatively correlated with Alistipes, Ruminococcae, Tenericides, and Porphyromonas (P < 0.05).CONCLUSIONOur results highlight that Hcy was correlated with cognition and gut microbiome in MDD. This interaction may berelated to the physiological and pathological mechanisms underlying cognitive deficits in depression. 展开更多
关键词 HOMOCYSTEINE MICROBIOME Intestinal flora Gut microbiota Gut-brain axis Major depressive disorder cognitive function cognitive impairment
在线阅读 下载PDF
Gamma-glutamyl transferase 5 overexpression in cerebrovascular endothelial cells improves brain pathology,cognition,and behavior in APP/PS1 mice
3
作者 Yanli Zhang Tian Li +8 位作者 Jie Miao Zhina Zhang Mingxuan Yang Zhuoran Wang Bo Yang Jiawei Zhang Haiting Li Qiang Su Junhong Guo 《Neural Regeneration Research》 SCIE CAS 2025年第2期533-547,共15页
In patients with Alzheimer’s disease,gamma-glutamyl transferase 5(GGT5)expression has been observed to be downregulated in cerebrovascular endothelial cells.However,the functional role of GGT5 in the development of A... In patients with Alzheimer’s disease,gamma-glutamyl transferase 5(GGT5)expression has been observed to be downregulated in cerebrovascular endothelial cells.However,the functional role of GGT5 in the development of Alzheimer’s disease remains unclear.This study aimed to explore the effect of GGT5 on cognitive function and brain pathology in an APP/PS1 mouse model of Alzheimer’s disease,as well as the underlying mechanism.We observed a significant reduction in GGT5 expression in two in vitro models of Alzheimer’s disease(Aβ_(1-42)-treated hCMEC/D3 and bEnd.3 cells),as well as in the APP/PS1 mouse model.Additionally,injection of APP/PS1 mice with an adeno-associated virus encoding GGT5 enhanced hippocampal synaptic plasticity and mitigated cognitive deficits.Interestingly,increasing GGT5 expression in cerebrovascular endothelial cells reduced levels of both soluble and insoluble amyloid-βin the brains of APP/PS1 mice.This effect may be attributable to inhibition of the expression ofβ-site APP cleaving enzyme 1,which is mediated by nuclear factor-kappa B.Our findings demonstrate that GGT5 expression in cerebrovascular endothelial cells is inversely associated with Alzheimer’s disease pathogenesis,and that GGT5 upregulation mitigates cognitive deficits in APP/PS1 mice.These findings suggest that GGT5 expression in cerebrovascular endothelial cells is a potential therapeutic target and biomarker for Alzheimer’s disease. 展开更多
关键词 Alzheimer’s disease amyloid-β APP/PS1 mice cerebrovascular endothelial cells cognitive deficits gamma-glutamyl transferase 5 neurovascular unit nuclear factor‐kappa B synaptic plasticity β-site APP cleaving enzyme 1
在线阅读 下载PDF
A Multi-Task Learning Framework for Joint Sub-Nyquist Wideband Spectrum Sensing and Modulation Recognition
4
作者 Dong Xin Stefanos Bakirtzis +1 位作者 Zhang Jiliang Zhang Jie 《China Communications》 2025年第1期128-138,共11页
The utilization of millimeter-wave frequencies and cognitive radio(CR)are promising ways to increase the spectral efficiency of wireless communication systems.However,conventional CR spectrum sensing techniques entail... The utilization of millimeter-wave frequencies and cognitive radio(CR)are promising ways to increase the spectral efficiency of wireless communication systems.However,conventional CR spectrum sensing techniques entail sampling the received signal at a Nyquist rate,and they are not viable for wideband signals due to their high cost.This paper expounds on how sub-Nyquist sampling in conjunction with deep learning can be leveraged to remove this limitation.To this end,we propose a multi-task learning(MTL)framework using convolutional neural networks for the joint inference of the underlying narrowband signal number,their modulation scheme,and their location in a wideband spectrum.We demonstrate the effectiveness of the proposed framework for real-world millimeter-wave wideband signals collected by physical devices,exhibiting a 91.7% accuracy in the joint inference task when considering up to two narrowband signals over a wideband spectrum.Ultimately,the proposed data-driven approach enables on-the-fly wideband spectrum sensing,combining accuracy,and computational efficiency,which are indispensable for CR and opportunistic networking. 展开更多
关键词 automated modulation classification cognitive radio convolutional neural networks deep learning spectrum sensing sub-Nyquist sampling
在线阅读 下载PDF
Outage performance analysis of multiple users in cognitive networks
5
作者 鲍煦 宋铁成 沈连丰 《Journal of Southeast University(English Edition)》 EI CAS 2010年第3期375-378,共4页
A cooperative model of multiple primary and secondary users coexisting cognitive network is presented. In this model, the control center is aware of all the users' locations in order to allocate the nearest secondary... A cooperative model of multiple primary and secondary users coexisting cognitive network is presented. In this model, the control center is aware of all the users' locations in order to allocate the nearest secondary user to the primary user. The control center is aware of the information of the unused spectral resources in terms of the feedback of the sensing results from the secondary users. It allocates idle frequency bands among the secondary users. The primary user accesses the base station (BS) in orthogonal subchannels, and it cooperatively transmits packets with the secondary user and exploits the free band assigned by the control center to amplify-and-forward what it receives immediately. Under this scenario, the outage probability of the cooperative transmission pair of the primary and secondary transmitters is derived. The numerical simulation of the outage probabilities as a function of primary transmission probability ps, power allocation ratio ξ between the primary and secondary users, and the numbers of the primary and secondary users are given respectively. The results show that the optimal system performance is achieved under the conditions of ξ=0.5 and the numbers of the primary and the secondary users being equal. 展开更多
关键词 cooperative transmission outage probability AMPLIFY-AND-FORWARD cognitive network
在线阅读 下载PDF
Impact of propofol and sevoflurane anesthesia on cognition and emotion in gastric cancer patients undergoing radical resection 被引量:3
6
作者 Ao-Han Li Su Bu +2 位作者 Ling Wang Ai-Min Liang Hui-Yu Luo 《World Journal of Gastrointestinal Oncology》 SCIE 2024年第1期79-89,共11页
BACKGROUND Propofol and sevoflurane are commonly used anesthetic agents for maintenance anesthesia during radical resection of gastric cancer.However,there is a debate concerning their differential effects on cognitiv... BACKGROUND Propofol and sevoflurane are commonly used anesthetic agents for maintenance anesthesia during radical resection of gastric cancer.However,there is a debate concerning their differential effects on cognitive function,anxiety,and depression in patients undergoing this procedure.AIM To compare the effects of propofol and sevoflurane anesthesia on postoperative cognitive function,anxiety,depression,and organ function in patients undergoing radical resection of gastric cancer.METHODS A total of 80 patients were involved in this research.The subjects were divided into two groups:Propofol group and sevoflurane group.The evaluation scale for cognitive function was the Loewenstein occupational therapy cognitive assessment(LOTCA),and anxiety and depression were assessed with the aid of the self-rating anxiety scale(SAS)and self-rating depression scale(SDS).Hemodynamic indicators,oxidative stress levels,and pulmonary function were also measured.RESULTS The LOTCA score at 1 d after surgery was significantly lower in the propofol group than in the sevoflurane group.Additionally,the SAS and SDS scores of the sevoflurane group were significantly lower than those of the propofol group.The sevoflurane group showed greater stability in heart rate as well as the mean arterial pressure compared to the propofol group.Moreover,the sevoflurane group displayed better pulmonary function and less lung injury than the propofol group.CONCLUSION Both propofol and sevoflurane could be utilized as maintenance anesthesia during radical resection of gastric cancer.Propofol anesthesia has a minimal effect on patients'pulmonary function,consequently enhancing their postoperative recovery.Sevoflurane anesthesia causes less impairment on patients'cognitive function and mitigates negative emotions,leading to an improved postoperative mental state.Therefore,the selection of anesthetic agents should be based on the individual patient's specific circumstances. 展开更多
关键词 PROPOFOL SEVOFLURANE Radical resection of gastric cancer Anesthetic effect cognitive function Negative emotion
在线阅读 下载PDF
Analysis of cumulative handoff delay for graded secondary users in cognitive radio networks
7
作者 Zhang Lei 张雷 +2 位作者 宋铁成 吴名 胡静 《Journal of Southeast University(English Edition)》 EI CAS 2013年第2期111-117,共7页
According to the fact that the secondary users' delay requirements for data transmission are not unitary in cognitive radio networks, the secondary users are divided into two classes, denoted by SU1 and SU2, respecti... According to the fact that the secondary users' delay requirements for data transmission are not unitary in cognitive radio networks, the secondary users are divided into two classes, denoted by SU1 and SU2, respectively. It is assumed that SU1 has a higher priority to occupy the primary users' unutilized channels than SU2. A preemptive resume priority M/G/1 queuing network is used to model the multiple spectrum handoffs processing. By using a state transition probability matrix and a cost matrix, the average cumulative delays of SU1 and SU2 are calculated, respectively. Numerical results show that the more the primary user's traffic load, the more rapidly the SU2's cumulative handoff delay grows. Compared with the networks where secondary users are unitary, the lower the SUI's arrival rate, the more obviously both SUI's and SU2's handoff delays decrease. The admission access regions limited by the maximum tolerable delay can also facilitate the design of admission control rules for graded secondary users. 展开更多
关键词 cognitive radio network graded secondary users multiple spectrum handoffs cumulative handoff delay admission access region
在线阅读 下载PDF
Interference Alignment Based on Subspace Tracking in MIMO Cognitive Networks with Multiple Primary Users 被引量:1
8
作者 XIE Xianzhong XIONG Zebo 《China Communications》 SCIE CSCD 2014年第A01期164-170,共7页
The interference alignment (IA) algorithm based on FDPM subspace tracking (FDPM-ST IA) is proposed for MIMO cognitive network (CRN) with multiple primary users in this paper. The feasibility conditions of FDPM-S... The interference alignment (IA) algorithm based on FDPM subspace tracking (FDPM-ST IA) is proposed for MIMO cognitive network (CRN) with multiple primary users in this paper. The feasibility conditions of FDPM-ST IA is also got. Futherly, IA scheme of secondary network and IA scheme of primary network are given respectively without assuming a priori knowledge of interference covariance matrices. Moreover, the paper analyses the computational complexity of FDPM-ST IA. Simulation results and theoretical calculations show that the proposed algorithm can achieve higher sum rate with lower computational complexity. 展开更多
关键词 MIMO cognitive networks multiple primary users subspace tracking interference alignment sum rate computational complexity
在线阅读 下载PDF
Hepatitis B Surface Antigen and Hepatitis C Virus Antibodies among Drug Users in Burkina Faso
9
作者 Sylvie Zida Kadari Cissé +13 位作者 Odette Ky-Zerbo Dinanibè Kambiré Serge Théophile Soubeiga Simon Tiendrebéogo Fatou Sissoko Issa Sory Célestine Ki-Toé Solange Dioma Djeneba Zorom Adama Ouédraogo Cedric Dimitri Axon Hien Mahamoudou Sanou Seni Kouanda Henri Gautier Ouédraogo 《Advances in Microbiology》 CAS 2024年第1期92-104,共13页
Introduction: The epidemiology of both hepatitis B virus (HBV) and hepatitis C virus (HCV) infections among drug users (DUs) is little known in West Africa. The study aimed to assess the prevalence of hepatitis B and ... Introduction: The epidemiology of both hepatitis B virus (HBV) and hepatitis C virus (HCV) infections among drug users (DUs) is little known in West Africa. The study aimed to assess the prevalence of hepatitis B and C viruses among drug users in Burkina Faso. Methodology: This was a cross-sectional biological and behavioral survey conducted between June and August 2022, among drug users in Ouagadougou and Bobo Dioulasso, the two main cities of Burkina Faso. A respondent-driven sampling (RDS) was used to recruit drug users. Hepatitis B surface antigen was determined using lateral flow rapid test kits and antibodies to hepatitis C virus in serum determined using an Enzyme-Linked Immunosorbent Assay. Data were entered and analyzed using Stata 17 software. Weighted binary logistic regression was used to identify the associated factors of hepatitis B and C infections and a p-value Results: A total of 323 drug users were recruited with 97.5% males. The mean age was 32.7 years old. The inhaled or smoked mode was the most used by drug users. The adjusted hepatitis B and hepatitis C prevalence among study participants were 11.1% and 2.3% respectively. The marital status (p = 0.001), and the nationality (p = 0.011) were significantly associated with hepatitis B infection. The type of drug used was not significantly associated with hepatitis B infection or hepatitis C infection. Conclusion: The prevalence of HBsAg and anti-HCV antibodies among DUs are comparable to those reported in the general population in Burkina Faso. This result suggests that the main routes of contamination by HBV and HCV among DUs are similar to those in the population, and could be explained by the low use of the injectable route by DUs in Burkina Faso. 展开更多
关键词 Drug users Hepatitis C Hepatitis B PREVALENCE Burkina Faso
在线阅读 下载PDF
User Recognition System Based on Spectrogram Image Conversion Using EMG Signals 被引量:2
10
作者 Jae Myung Kim Gyu Ho Choi +1 位作者 Min-Gu Kim Sung Bum Pan 《Computers, Materials & Continua》 SCIE EI 2022年第7期1213-1227,共15页
Recently,user recognitionmethods to authenticate personal identity has attracted significant attention especially with increased availability of various internet of things(IoT)services through fifth-generation technol... Recently,user recognitionmethods to authenticate personal identity has attracted significant attention especially with increased availability of various internet of things(IoT)services through fifth-generation technology(5G)based mobile devices.The EMG signals generated inside the body with unique individual characteristics are being studied as a part of nextgeneration user recognition methods.However,there is a limitation when applying EMG signals to user recognition systems as the same operation needs to be repeated while maintaining a constant strength of muscle over time.Hence,it is necessary to conduct research on multidimensional feature transformation that includes changes in frequency features over time.In this paper,we propose a user recognition system that applies EMG signals to the short-time fourier transform(STFT),and converts the signals into EMG spectrogram images while adjusting the time-frequency resolution to extract multidimensional features.The proposed system is composed of a data pre-processing and normalization process,spectrogram image conversion process,and final classification process.The experimental results revealed that the proposed EMG spectrogram image-based user recognition system has a 95.4%accuracy performance,which is 13%higher than the EMGsignal-based system.Such a user recognition accuracy improvement was achieved by using multidimensional features,in the time-frequency domain. 展开更多
关键词 EMG user recognition SPECTROGRAM CNN
在线阅读 下载PDF
Evaluation of an Autonomous Vehicle User Interface for Sensory Impaired Users
11
作者 Elena Angeleska Linda Lüchtrath Paolo Pretto 《Journal of Transportation Technologies》 2024年第4期570-589,共20页
Autonomous vehicles (AVs) hold immense promises in revolutionizing transportation, and their potential benefits extend to individuals with impairments, particularly those with vision and hearing impairments. However, ... Autonomous vehicles (AVs) hold immense promises in revolutionizing transportation, and their potential benefits extend to individuals with impairments, particularly those with vision and hearing impairments. However, the accommodation of these individuals in AVs requires developing advanced user interfaces. This paper describes an explorative study of a multimodal user interface for autonomous vehicles, specifically developed for passengers with sensory (vision and/or hearing) impairments. In a driving simulator, 32 volunteers with simulated sensory impairments, were exposed to multiple drives in an autonomous vehicle while freely interacting with standard and inclusive variants of the infotainment and navigation system interface. The two user interfaces differed in graphical layout and voice messages, which adopted inclusive design principles for the inclusive variant. Questionnaires and structured interviews were conducted to collect participants’ impressions. The data analysis reports positive user experiences, but also identifies technical challenges. Verified guidelines are provided for further development of inclusive user interface solutions. 展开更多
关键词 Autonomous Vehicles user Interface Inclusive Design Wizard of Oz Simulation
在线阅读 下载PDF
Optimal spectrum allocation of primary users in light-handed cognitive radio networks 被引量:1
12
作者 司鹏博 孙恩昌 张延华 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2012年第3期21-27,共7页
In traditional cognitive radio(CR) network,secondary users(SUs) are always assumed to obey the rule of"introducing no interference to the primary users(PUs) ".However,this assumption may be not realistic as ... In traditional cognitive radio(CR) network,secondary users(SUs) are always assumed to obey the rule of"introducing no interference to the primary users(PUs) ".However,this assumption may be not realistic as the CR devices becoming more and more intelligent nowadays.In this paper,with the concept of lighthanded CR,which is proposed to deal with the above mentioned problem by enforcing"punishment"to illegal CR transmissions,the action decisions of primary users(PUs) are modeled as a partially observable Markov decision process(POMDP),and the optimal spectrum allocation scheme with the objective of maximizing their reward is proposed,which is defined by the utility function.Furthermore,a reduced scheme with much smaller state space has been proposed in this paper for lower computational complexity.Extensive simulation results show that the proposed schemes improve the reward significantly compared to the existing scheme. 展开更多
关键词 cognitive radio networks light-handed CR optimal decision making POMDP
在线阅读 下载PDF
Reform of the Irrigation Sector and Creation of Functional and Sustainable Irrigation Water Users Associations (AUEI) in Niger: Capitalization of the Experience of the Konni AHA
13
作者 Saidou Abdoulkarimou Illou Mahamadou 《Agricultural Sciences》 2024年第2期209-229,共21页
During the 1980s, as part of a policy of liberalization, following budgetary cuts linked to the implementation of structural adjustment programs, management responsibilities for AHAs were transferred from ONAHA to coo... During the 1980s, as part of a policy of liberalization, following budgetary cuts linked to the implementation of structural adjustment programs, management responsibilities for AHAs were transferred from ONAHA to cooperatives concerned. Due to lack of financial resources, but also because of poor management, everywhere in Niger we are witnessing an accelerated deterioration of the irrigation infrastructure of hydro-agricultural developments. Institutional studies carried out on this situation led the State of Niger to initiate a reform of the governance of hydro-agricultural developments, by streng-thening the status of ONAHA, by creating an Association of Irrigation Water Users (AUEI) and by restructuring the old cooperatives. Indeed, this research aims to analyze the creation of functional and sustainable Irrigation Water User Associations (AUEI) in Niger in a context of reform of the irrigation sector, and based on the experience of the Konni AHA. It is based on a methodological approach which takes into account documentary research and the collection of data from 115 farmers, selected by reasoned choice and directly concerned by the management of the irrigated area. The data collected was analyzed and the results were analyzed using the systemic approach and the diagnostic process. The results show that the main mission of the AUEI is to ensure better management of water, hydraulic equipment and infrastructure on the hydro-agricultural developments of Konni. The creation of the Konni AUEI was possible thanks to massive support from the populations and authorities in the implementation process. After its establishment, the AUEI experienced a certain lethargy for some time due to the rehabilitation work of the AHA but currently it is functional and operational in terms of associative life and governance. Thus, the constraints linked to the legal system, the delay in the completion of the work, the uncertainties of access to irrigation water but also the problems linked to the change in mentality of certain ONAHA agents constitute the challenges that must be resolved in the short term for the operationalization of the Konni AUEI. 展开更多
关键词 Konni (Niger) Hydro-Agricultural Developments Association of Irrigation Water users GOVERNANCE
在线阅读 下载PDF
Cooperative Jamming for Enhancing Security of Cognitive Radio Networks with Multiple Primary Users 被引量:3
14
作者 Xiaofeng Feng Xinbo Gao Ru Zong 《China Communications》 SCIE CSCD 2017年第7期93-107,共15页
In cognitive radio networks(CRNs), through recruiting secondary user(SU) as friendly jammer, the secrecy rate obtained by primary user(PU) can be improved. Previous work only considered a simple scenario with a single... In cognitive radio networks(CRNs), through recruiting secondary user(SU) as friendly jammer, the secrecy rate obtained by primary user(PU) can be improved. Previous work only considered a simple scenario with a single PU in their frameworks. In this paper, we will consider a more complicated scenario with multiple PUs and try to investigate the cooperative jamming between multiple PUs and a single SU. When there are multiple PUs in CRN, in order to obtain more spectrum for data transmission, SU will cooperate with multiple PUs at the same time. Considering that both PU and SU are rational and selfish individuals, the interaction between PUs and SU is formulated as a multi-leaders and single-follower Stackelberg game, wherein PU is the leader and SU is the follower. And the Stackelberg Equilibrium(SE) is considered as the final decisions accepted by all PUs and SU. Furthermore, we also prove that when a specific condition is satisfied, the existence of SE can be guaranteed. And a Gauss-Jacobi iterative algorithm is proposed to compute a SE. Finally, simulation results are given to verify the performance and demonstrate that both of the PUs' secrecy rate and the SU's transmission rate can be improved through cooperation. 展开更多
关键词 cognitive radio networks cooperative jamming physical layer security spectrum sharing stackelberg game
在线阅读 下载PDF
Cooperative Spectrum Sensing Exploiting a Certain Number of CR Users Based on Multi- Antennas in Cognitive Radio Networks 被引量:2
15
作者 WANG Xiaoxiang WANG Jing +1 位作者 WANG Yulong MA Bo 《China Communications》 SCIE CSCD 2010年第4期149-155,共7页
In this paper,a cooperative spectrum sensing scheme,which is based on cooperation of a certain number of secondary users and cooperative diversity under multi-antenna scenario,is proposed.Under multi-antenna scenario,... In this paper,a cooperative spectrum sensing scheme,which is based on cooperation of a certain number of secondary users and cooperative diversity under multi-antenna scenario,is proposed.Under multi-antenna scenario,we set a targeted detection probability and optimize the false alarm probability of the network by choosing a certain number of secondary users with the highest primary user’s signal to noise ratio.The detection performance of the network is also evaluated when all the secondary users are cooperating to illustrate the benefits of the proposed scheme as a contrast.In addition,how to choose the detection threshold of the secondary user is analyzed for the purpose of decreasing the average risk.Theory analysis and simulation results show that the optimum false alarm probability can be derived by cooperating a certain number of secondary users rather than all the secondary users and the detection performance of the network can be further improved if secondary users are equipped with multiple antennas.Also,a minimum average risk can be obtained by optimizing the detection threshold. 展开更多
关键词 cognitive Radio Cooperative Spectrum Sensing Multiple Antennas Detection Threshold.
在线阅读 下载PDF
Detection Performance Analysis of Spectrum Sensing in Cognitive Radio Networks with Mobile Secondary Users 被引量:2
16
作者 Xinyu Wang Min Jia +2 位作者 Qing Guo Xuemai Gu Jian Yang 《China Communications》 SCIE CSCD 2016年第11期214-225,共12页
The majority of existing papers about spectrum sensing have the assumption that secondary users(SUs) are stationary. However,mobility is an essential feature of mobile communications networks. In this paper,the detect... The majority of existing papers about spectrum sensing have the assumption that secondary users(SUs) are stationary. However,mobility is an essential feature of mobile communications networks. In this paper,the detection performance of spectrum sensing by mobile SUs was analyzed. Three performance metrics,i.e.,detection probability,miss detection probability and false alarm probability,were thoroughly investigated. In our analysis,a critical variable was the real-time received primary user signal power by a mobile SU. Its probability distribution and mathematical expectation were analytically derived. Moreover,the three performance metrics in single-node spectrum sensing and multi-node collaborative spectrum sensing systems were also derived. Extensive simulations were performed. The results are consistent with the theoretical analysis. And it is concluded that SU mobility has a significant impact on the detection probability and the miss detection probability,but not on the false alarm probability. 展开更多
关键词 cognitive radio spectrum sensing MOBILITY random variable analysis probability density function
在线阅读 下载PDF
Interference Alignment Algorithm for Considering the Throughput of Cognitive Users in Cognitive MIMO Network 被引量:1
17
作者 张慧杰 李莉 +1 位作者 邱昊 夏林 《Journal of Donghua University(English Edition)》 EI CAS 2015年第3期481-484,共4页
The cognitive multiple input multiple output( MIMO)network can utilize radio spectrum efficiently and satisfy the demand of high data rate. In order to decrease the interference during transmission,a new interference ... The cognitive multiple input multiple output( MIMO)network can utilize radio spectrum efficiently and satisfy the demand of high data rate. In order to decrease the interference during transmission,a new interference alignment( IA) algorithm based on cognitive MIMO networks is proposed in this paper. The algorithm is realized by designing two-level pre-coding, the first-level precoding aligns the interference generated by the cognitive users( CUs) to unused sub-channels of the primary user( PU),thereby eliminating the interference of CUs to PU; the second-level precoding is used to improve the throughput of CUs. Simulation shows that the proposed IA algorithm can eliminate the interference that the CUs produce on the PU and improve the throughput of CUs spontaneously. 展开更多
关键词 cognitive multiple input multiple output(MIMO) interference alignment(IA) pre-coding
在线阅读 下载PDF
Design Method for Optimizing the Interactive Interface of Live Broadcasting Platform for the Elderly Users
18
作者 WEI Bi-ze FAN Wei DUAN Ying-ke 《印刷与数字媒体技术研究》 CAS 北大核心 2024年第4期167-178,共12页
In the era of network live broadcasting for everyone,the development of live broadcasting platforms is also more intelligent and diversified.However,in the face of a large group of elderly users,the interface interact... In the era of network live broadcasting for everyone,the development of live broadcasting platforms is also more intelligent and diversified.However,in the face of a large group of elderly users,the interface interaction design mode used is still mainly based on the interaction mode for young groups,and is not designed for elderly users.Therefore,a design method for optimizing the interaction interface of live broadcasting platform for elderly users was proposed in this study.Firstly,the case study method and Delphi expert survey method were used to determine the design needs of elderly users and the design mode was analysed.Secondly,the orthogonal design principle was used to design a test sample of the interactive interface of live broadcasting platform applicable for the elderly users,and then a user evaluation system was established to calculate the weights of the design elements using hierarchical analysis,and then the predictive relationship between the design mode of the interactive interface of live broadcasting platform and the elderly users was established by Quantitative Theory I.Finally,Genetic Algorithm was applied to generate the optimized design scheme.The results showed that the design method based on the Genetic Algorithm and the combination of Quantitative Theory can scientifically and effectively optimize the design of the interactive interface of the live broadcasting platform for the elderly users,and improve the experience of the elderly users. 展开更多
关键词 Live broadcasting platform Interaction design Elderly users Genetic Algorithm Quantitative Theory I
在线阅读 下载PDF
On the Backlog and Delay Distributions of Primary and Secondary Users in a Cognitive Radio Network 被引量:2
19
作者 Gao Yuehong Jiang Yuming Zhang Xin 《China Communications》 SCIE CSCD 2010年第5期23-28,共6页
In a cognitive radio network, the secondary users can use the spectrum holes when the primary users do not utilize the spectrum, but they must vacant the spectrum when the primary users need to transmit data on the sp... In a cognitive radio network, the secondary users can use the spectrum holes when the primary users do not utilize the spectrum, but they must vacant the spectrum when the primary users need to transmit data on the spectrum. In other words, the primary users have higher priority over the secondary users. In this paper, backlog and delay distribution bounds for both primary users and secondary users are obtained. The analysis is based on stochastic network calculus, for which, stochastic service curves are t-n-st derived for both primary users and secondary users, and the network calculus independent case analysis approach is used to find the distribution bounds. Numerical results and simulation results are also presented and discussed. 展开更多
关键词 cognitive radio probability distrbution stochastic network calculus stochastic service curve independent case analysis
在线阅读 下载PDF
User-centric avatar design:a cognitive walkthrough approach for metaverse in virtual education
20
作者 Hasan Tinmaz Preet Kawal Singh Dhillon 《Data Science and Management》 2024年第4期267-282,共16页
Metaverse,once a concept confined to science fiction,has emerged as a transformative reality during the digital era.As this immersive virtual world gains prominence,the role of avatars and the digital representations ... Metaverse,once a concept confined to science fiction,has emerged as a transformative reality during the digital era.As this immersive virtual world gains prominence,the role of avatars and the digital representations of users in shaping educational experiences within a metaverse becomes increasingly crucial.This study examined the design of avatars and their effectiveness in virtual education.Using the cognitive walkthrough(CW)method,a well-established user-centric assessment approach,this study examined how users engage in avatar design in virtual educational settings,highlighting their cognitive processes.Through the CW approach,this study identified usability issues and learning challenges,providing valuable insights into the user experience.The investigation focuses on the VRoid platform for avatar design,selected for its user-friendly interface and robust customization features.Participants(n=12;six men and six women)from diverse educational backgrounds were carefully selected to offer a comprehensive range of perspectives.They performed avatar design tasks that closely mirrored the learning environment of the metaverse,followed by in-depth post-exercise interviews.The findings of this study highlight the essential role of avatar design in enhancing user engagement and improving the learning outcomes of virtual education.Furthermore,we provide practical recommendations for educators and designers to effectively leverage avatar innovation.In a continuously evolving era of metaverse,this research contributes significantly to the ongoing discourse on user-centered design in educational settings,thereby influencing the future trajectory of virtual education. 展开更多
关键词 Metaverse AVATAR cognitive walkthrough user experience design Digital persona Avatar customization
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部