Novel Spectrum Allocation Algorithm Based on the Activities of Primary Users for Cognitive Radio Networks

In traditional cognitive radio (CR) network, most existing graph-based spectrum allocation schemes don't take on-off behavior of primary users (PUs) into consideration. In this paper, a novel spectrum allocation algorithm based on the activities of the PUs is proposed. The proposed algorithm mainly focuses on the vacant probability of licensed spectrums. And it allocates the vacant spectrums considering the interference to the neighbor cognitive nodes and the probability fairness of different cognitive nodes during the allocation. Based on the definition of the obtained benefit of cognitive node, new utility functions are formulated to characterize the system total spectrum utilization and fairness performance from the perspective of available probability. The simulation results validate that the proposed algorithm with low system communication cost is more effective than the traditional schemes when the available licensed spectrums are not sufficient, which is effective and meaningful to a real CR system with bad network condition.

Exploration of the Role-Playing Model in Primary School Class Activities Under the Background of“Class Activity Month”

Education in the new era advocates taking students as the main body and improving students’core literacy on this basis.Subjectivity has also become one of the keys to quality education.Primary school is not only the initial stage of life,but also the key period to develop students’subjectivity.At present,there are many problems in class activities,such as the weak concept of taking students as the main body,the lack of subject consciousness among students,the flawed construction system of class activities,the unreasonable evaluation system of class activities,and so on.By establishing the role-playing model under the background of“class activity month,”students can play different roles in class activities and participate in various links,such as theme selection,scheme design,organization,implementation,summary,and evaluation of class activities.Through this process,it does not only improve the quality of class activities,but also cultivate students’subject consciousness and ability in a certain subject,thus highlighting their subject status in class activities.

Altered intrinsic functional connectivity of the primary visual cortex in youth patients with comitant exotropia: a resting state fMRI study

AIM： To evaluate the differences in the functional connectivity（FC） of the primary visual cortex（V1） between the youth comitant exotropia（CE） patients and health subjects using resting functional magnetic resonance imaging（f MRI） data.METHODS： Totally, 32 CEs（25 males and 7 females） and 32 healthy control subjects（HCs）（25 males and 7 females） were enrolled in the study and underwent the MRI scanning. Two-sample t-test was used to examine differences in FC maps between the CE patients and HCs. RESULTS： The CE patients showed significantly less FC between the left brodmann area（BA17） and left lingual gyrus/cerebellum posterior lobe, right middle occipital gyrus, left precentral gyrus/postcentral gyrus and right inferior parietal lobule/postcentral gyrus. Meanwhile, CE patients showed significantly less FC between right BA17 and right middle occipital gyrus（BA19, 37）.CONCLUSION： Our findings show that CE involves abnormal FC in primary visual cortex in many regions, which may underlie the pathologic mechanism of impaired fusion and stereoscopic vision in CEs.

Green Value Chain： A Case Study in Turkey about the Relationships among Antecedents, Initiatives and Results of Green Value Chain Implementations

The present study was conducted to determine the green value chain implementations of large and medium size businesses and to investigate the relationships among antecedents, initiatives and results of green value chain implementations. The antecedents of green value chain implementations were considered from four dimensions namely regulations, public concerns, expected competitive advantage and top management commitment; green value chain initiatives were considered from three dimensions namely green primary activities, green internal support activities and green external support activities; the results of green value chain implementations were considered from two dimensions namely economic performance and socio-ecologic performance. A model was created according to the objectives of the study and hypotheses were formed. Multiple regression analyses were performed to investigate the relationships between the antecedents and initiatives of green value chain implementations. A relationship was not observed between green primary activities and economic and socio-ecologic performance. While a positive relationship was observed between green external support activities and economic performance, a positive relationship was observed between green internal support activities and both economic and socio-ecologic performance.

Expeditious solvent-free synthesis of 1,3-thiazolanes via multicomponent reactions

A series of 1 3-thiazolane derivatives have been synthesized via multicomponent reactions of activated acetylenes,primary amines and isothiocyanates in the presence of a catalytic amount of Nmethylimidazole under solvent-free conditions.

上期临床病案讨论结果

上期临床病案讨论结果术前诊断左上腹巨大包块：①腹膜后包块（嗜铬细胞瘤？）；②左肝肿瘤？手术情况于１９９４年５月７日在静脉复合麻醉下取双侧肋缘下人字形切口行剖腹探查术。术中见肝脏正常，未扣及结节或肿块，但在左肝下缘与胃小弯之间发现一凸出的巨大肿块。切开...