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
To evaluate brain involvement in quiescent Crohn’s disease (CD) patients with fatigue using quantitative magnetic resonance imaging (MRI).METHODSMultiple MRI techniques were used to assess cerebral changes in 20 quie...To evaluate brain involvement in quiescent Crohn’s disease (CD) patients with fatigue using quantitative magnetic resonance imaging (MRI).METHODSMultiple MRI techniques were used to assess cerebral changes in 20 quiescent CD patients with fatigue (defined with at least 6 points out of an 11-point numeric rating scale compared with 17 healthy age and gender matched controls without fatigue. Furthermore, mental status was assessed by cognitive functioning, based on the neuropsychological inventory including the different domains global cognitive functioning, memory and executive functioning and in addition mood and quality of life scores. Cognitive functioning and mood status were correlated with MRI findings in the both study groups.RESULTSReduced glutamate + glutamine (Glx = Glu + Gln) concentrations (P = 0.02) and ratios to total creatine (P = 0.02) were found in CD patients compared with controls. Significant increased Cerebral Blood Flow (P = 0.05) was found in CD patients (53.08 ± 6.14 mL/100 g/min) compared with controls (47.60 ± 8.62 mL/100 g/min). CD patients encountered significantly more depressive symptoms (P < 0.001). Cognitive functioning scores related to memory (P = 0.007) and executive functioning (P = 0.02) were lower in CD patients and both scores showed correlation with depression and anxiety. No correlation was found subcortical volumes between CD patients and controls in the T<sub>1</sub>-weighted analysis. In addition, no correlation was found between mental status and MRI findings.CONCLUSIONThis work shows evidence for perfusion, neurochemical and mental differences in the brain of CD patients with fatigue compared with healthy controls.展开更多
The paper analyzes the current trends of urban transformation and delineates an underlying rationale which enables the comprehension of the current character of Arab city with particular reference to Al-Khobar. The ci...The paper analyzes the current trends of urban transformation and delineates an underlying rationale which enables the comprehension of the current character of Arab city with particular reference to Al-Khobar. The city form is subjected to a re-reading arguments of which are based on critical interpretation of the mechaitisms of urban morphology in relation not only to the impacts of global economy and building boom but also to the means of perception of urban space by different strata of the urban realm. Thus, urban morphology of the city is studied as a medium which manifests a dissociation, and thus duality, between social structure and its physical container. The paper further argues that uncritical import of urban and architectural typologies seem to create a peculiar type of urban-architectural forgery that is usually reduced to skin-deep facade mimicry. Particularly, solo performances of shiny high-rise buildings and sharp contrasts of street fronts between main arteries and back streets depict impressions of fragmentation and segregation. The emerging urban-scape that can be associated with the cultural and economic leap in Arab regions today is critically evaluated. Thus, the paper proposes judicious and critical planning policy instead of direct import of global urban-architectural typologies.展开更多
Affect plays a significant role in college English teaching and learning, in which teachers, learners, tasks and contexts or environments interact with each other, developing a system of affective interaction. In the ...Affect plays a significant role in college English teaching and learning, in which teachers, learners, tasks and contexts or environments interact with each other, developing a system of affective interaction. In the system, the teacher is a facilitator and mediator and the learner is the subject of English learning. In a harmonious and friendly classroom environment, with the knowledge transmission blending in well with the cultivation of affect, attitudes and values, students＇ cognitive and emotional development can be promoted. The experimental results of the present study indicated that students in the affective college English classroom did significantly better （p〈 .05） in cognition than before. Furthermore, the analyses of the two surveys showed that attention to affective interaction in college English teaching helped students enhance their interest in college English learning, cross-cultural awareness, self-confidence, interpersonal intelligence, and so forth. Therefore, our conclusion is that attention to affective interaction in college English classroom teaching is conducive to students＇ personal growth and a more holistic development.展开更多
This paper which is directed to constructing the cognitive model of knowledge acquisition in view of the increasing need of globalization-oriented study, points out features of globalization-oriented study, and propos...This paper which is directed to constructing the cognitive model of knowledge acquisition in view of the increasing need of globalization-oriented study, points out features of globalization-oriented study, and proposes the importance and necessity for constructing the CMKAGS （cognitive model of knowledge acquisition in globalization-oriented study） which includes attention, background knowledge, and chunking memory that involves semantic chunking, information encoding as well as choice of information encoding. The cognitive model of knowledge acquisition in question aims at helping e-learners to memorize their learned knowledge and improve their studies effectively and efficiently, whether they study in enhanced conditions or in natural conditions展开更多
In this paper,we propose a securityoriented transmission scheme with the help of multiple relays in Cognitive Radio(CR).To maximise the Secrecy Capacity(SC)of the source-destination link in CR,both beamforming and coo...In this paper,we propose a securityoriented transmission scheme with the help of multiple relays in Cognitive Radio(CR).To maximise the Secrecy Capacity(SC)of the source-destination link in CR,both beamforming and cooperative jamming technologies are used to improve the performance of the Secondary User(SU)and protect the Primary User(PU).The effectiveness of the proposed scheme is demonstrated using extensive simulation.Both theoretical analyses and simulation results reveal that the proposed scheme contributes to the secure transmission of the SU with acceptable attenuation of the Signal-to-Noise Ratio(SNR)at the PU receiver,and the upper bound of the SC at the SU receiver is able to exploit the power allocation strategy.展开更多
Farmers are both the producers and consumers of food, and as such have a dual role in food safety： they both generate risks and are exposed to them. Based upon a survey of the food production and consumption habits o...Farmers are both the producers and consumers of food, and as such have a dual role in food safety： they both generate risks and are exposed to them. Based upon a survey of the food production and consumption habits of 140 farm households and long-term research in two villages in Yunnan province, this study found that rural families are highly dependent on the market for food production and consumption. In their role as consumers, farmers are aware of food safety risks and concerned about them, but their ability to protect themselves is limited. They do so primarily by avoiding certain products and growing as much of their own food as possible. At the same time, in their role as producers, farmers engage in practices, primarily the overuse and inappropriate use of fertilizer and pesticides, that are damaging to food safety and the environment. There is therefore a disconnect in their roles as consumers and producers that needs to be addressed if policy goals for improving food safety and reducing the use of agricultural chemicals are to be achieved. Farmers need more information about food safety risks related to the products they consume themselves, and technical guidance on the safe use of farm chemicals when growing food for market. However, such measures will not be effective unless the external pressures on farmers are also addressed, through consideration of market incentives to use farm chemicals and the impact of consumer demand.展开更多
OBJECTIVE: To study cognitive function and cerebral metabolic changes in patients with transient global amnesia (TGA). METHODS: Three patients with TGA were given mini-mental state examination (MMSE), revised Wechsler...OBJECTIVE: To study cognitive function and cerebral metabolic changes in patients with transient global amnesia (TGA). METHODS: Three patients with TGA were given mini-mental state examination (MMSE), revised Wechsler memory scale (WMS-R) examination and magnetic resonance imaging (MRI) scans after they had been diagnosed as TGA. Using (18)F labelled deoxyglucose as tracer, patients were given a positron emission tomography (PET) examination at different periods during recovery. RESULTS: No obvious abnormality was found in MMSE and MRI scans in the three patients. However, WMS-R examination and cerebral PET imaging displayed cognitive dysfunction of varying degrees and low metabolism in local areas related to memory in 2 of 3 patients. CONCLUSIONS: In TGA patients, cognitive function and cerebral metabolic levels are closely correlated with duration of symptoms. It is necessary to stop the TGA attack as quickly as possible early time.展开更多
We investigate the secrecy outage performance of maximal ratio combining(MRC) in cognitive radio networks over Rayleigh fading channels. In a single-input multiple-output wiretap system, we consider a secondary user(S...We investigate the secrecy outage performance of maximal ratio combining(MRC) in cognitive radio networks over Rayleigh fading channels. In a single-input multiple-output wiretap system, we consider a secondary user(SU-TX) that transmits confidential messages to another secondary user(SU-RX) equipped with M(M ≥ 1)antennas where the MRC technique is adopted to improve its received signal-to-noise ratio. Meanwhile, an eavesdropper equipped with N(N ≥ 1) antennas adopts the MRC scheme to overhear the information between SU-TX and SU-RX. SU-TX adopts the underlay strategy to guarantee the service quality of the primary user without spectrum sensing. We derive the closed-form expressions for an exact and asymptotic secrecy outage probability.展开更多
基金supported in part by the National Key Research and Development Program of China under Grant 2016QY01W0204in part by Key Industrial Innovation Chain in Industrial Domain under Grant 2016KTZDGY-02in part by National High-Level TalentsSpecial Support Program of China under Grant CS31117200001
文摘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.
文摘To evaluate brain involvement in quiescent Crohn’s disease (CD) patients with fatigue using quantitative magnetic resonance imaging (MRI).METHODSMultiple MRI techniques were used to assess cerebral changes in 20 quiescent CD patients with fatigue (defined with at least 6 points out of an 11-point numeric rating scale compared with 17 healthy age and gender matched controls without fatigue. Furthermore, mental status was assessed by cognitive functioning, based on the neuropsychological inventory including the different domains global cognitive functioning, memory and executive functioning and in addition mood and quality of life scores. Cognitive functioning and mood status were correlated with MRI findings in the both study groups.RESULTSReduced glutamate + glutamine (Glx = Glu + Gln) concentrations (P = 0.02) and ratios to total creatine (P = 0.02) were found in CD patients compared with controls. Significant increased Cerebral Blood Flow (P = 0.05) was found in CD patients (53.08 ± 6.14 mL/100 g/min) compared with controls (47.60 ± 8.62 mL/100 g/min). CD patients encountered significantly more depressive symptoms (P < 0.001). Cognitive functioning scores related to memory (P = 0.007) and executive functioning (P = 0.02) were lower in CD patients and both scores showed correlation with depression and anxiety. No correlation was found subcortical volumes between CD patients and controls in the T<sub>1</sub>-weighted analysis. In addition, no correlation was found between mental status and MRI findings.CONCLUSIONThis work shows evidence for perfusion, neurochemical and mental differences in the brain of CD patients with fatigue compared with healthy controls.
文摘The paper analyzes the current trends of urban transformation and delineates an underlying rationale which enables the comprehension of the current character of Arab city with particular reference to Al-Khobar. The city form is subjected to a re-reading arguments of which are based on critical interpretation of the mechaitisms of urban morphology in relation not only to the impacts of global economy and building boom but also to the means of perception of urban space by different strata of the urban realm. Thus, urban morphology of the city is studied as a medium which manifests a dissociation, and thus duality, between social structure and its physical container. The paper further argues that uncritical import of urban and architectural typologies seem to create a peculiar type of urban-architectural forgery that is usually reduced to skin-deep facade mimicry. Particularly, solo performances of shiny high-rise buildings and sharp contrasts of street fronts between main arteries and back streets depict impressions of fragmentation and segregation. The emerging urban-scape that can be associated with the cultural and economic leap in Arab regions today is critically evaluated. Thus, the paper proposes judicious and critical planning policy instead of direct import of global urban-architectural typologies.
文摘Affect plays a significant role in college English teaching and learning, in which teachers, learners, tasks and contexts or environments interact with each other, developing a system of affective interaction. In the system, the teacher is a facilitator and mediator and the learner is the subject of English learning. In a harmonious and friendly classroom environment, with the knowledge transmission blending in well with the cultivation of affect, attitudes and values, students＇ cognitive and emotional development can be promoted. The experimental results of the present study indicated that students in the affective college English classroom did significantly better （p〈 .05） in cognition than before. Furthermore, the analyses of the two surveys showed that attention to affective interaction in college English teaching helped students enhance their interest in college English learning, cross-cultural awareness, self-confidence, interpersonal intelligence, and so forth. Therefore, our conclusion is that attention to affective interaction in college English classroom teaching is conducive to students＇ personal growth and a more holistic development.
文摘This paper which is directed to constructing the cognitive model of knowledge acquisition in view of the increasing need of globalization-oriented study, points out features of globalization-oriented study, and proposes the importance and necessity for constructing the CMKAGS （cognitive model of knowledge acquisition in globalization-oriented study） which includes attention, background knowledge, and chunking memory that involves semantic chunking, information encoding as well as choice of information encoding. The cognitive model of knowledge acquisition in question aims at helping e-learners to memorize their learned knowledge and improve their studies effectively and efficiently, whether they study in enhanced conditions or in natural conditions
基金supported by the National Natural Science Foundation of China under Grants No. 61201150, No. 61171097the Fundamental Research Funds for the Central Universities of BUPT under Grant No. 2013RC0202the State Major Science and Technology Special Projects under Grant No. 2012ZX03004001
文摘In this paper,we propose a securityoriented transmission scheme with the help of multiple relays in Cognitive Radio(CR).To maximise the Secrecy Capacity(SC)of the source-destination link in CR,both beamforming and cooperative jamming technologies are used to improve the performance of the Secondary User(SU)and protect the Primary User(PU).The effectiveness of the proposed scheme is demonstrated using extensive simulation.Both theoretical analyses and simulation results reveal that the proposed scheme contributes to the secure transmission of the SU with acceptable attenuation of the Signal-to-Noise Ratio(SNR)at the PU receiver,and the upper bound of the SC at the SU receiver is able to exploit the power allocation strategy.
基金FORHEAD with funding from the Rockefeller Brothers Fund(RBF)
文摘Farmers are both the producers and consumers of food, and as such have a dual role in food safety： they both generate risks and are exposed to them. Based upon a survey of the food production and consumption habits of 140 farm households and long-term research in two villages in Yunnan province, this study found that rural families are highly dependent on the market for food production and consumption. In their role as consumers, farmers are aware of food safety risks and concerned about them, but their ability to protect themselves is limited. They do so primarily by avoiding certain products and growing as much of their own food as possible. At the same time, in their role as producers, farmers engage in practices, primarily the overuse and inappropriate use of fertilizer and pesticides, that are damaging to food safety and the environment. There is therefore a disconnect in their roles as consumers and producers that needs to be addressed if policy goals for improving food safety and reducing the use of agricultural chemicals are to be achieved. Farmers need more information about food safety risks related to the products they consume themselves, and technical guidance on the safe use of farm chemicals when growing food for market. However, such measures will not be effective unless the external pressures on farmers are also addressed, through consideration of market incentives to use farm chemicals and the impact of consumer demand.
文摘OBJECTIVE: To study cognitive function and cerebral metabolic changes in patients with transient global amnesia (TGA). METHODS: Three patients with TGA were given mini-mental state examination (MMSE), revised Wechsler memory scale (WMS-R) examination and magnetic resonance imaging (MRI) scans after they had been diagnosed as TGA. Using (18)F labelled deoxyglucose as tracer, patients were given a positron emission tomography (PET) examination at different periods during recovery. RESULTS: No obvious abnormality was found in MMSE and MRI scans in the three patients. However, WMS-R examination and cerebral PET imaging displayed cognitive dysfunction of varying degrees and low metabolism in local areas related to memory in 2 of 3 patients. CONCLUSIONS: In TGA patients, cognitive function and cerebral metabolic levels are closely correlated with duration of symptoms. It is necessary to stop the TGA attack as quickly as possible early time.
基金Project supported in part by the National Natural Science Foundation of China(Nos.61401372 and 61531016)the Research Fund for the Doctoral Program of Higher Education of China(No.20130182120017)+1 种基金the Natural Science Foundation of CQ CSTC(No.cstc2013jcyj A40040)the Fundamental Research Funds for the Central Universities,China(No.XDJK2015B023)
文摘We investigate the secrecy outage performance of maximal ratio combining(MRC) in cognitive radio networks over Rayleigh fading channels. In a single-input multiple-output wiretap system, we consider a secondary user(SU-TX) that transmits confidential messages to another secondary user(SU-RX) equipped with M(M ≥ 1)antennas where the MRC technique is adopted to improve its received signal-to-noise ratio. Meanwhile, an eavesdropper equipped with N(N ≥ 1) antennas adopts the MRC scheme to overhear the information between SU-TX and SU-RX. SU-TX adopts the underlay strategy to guarantee the service quality of the primary user without spectrum sensing. We derive the closed-form expressions for an exact and asymptotic secrecy outage probability.
