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991.
WVD和XWVD的统计特征分析   总被引:4,自引:0,他引:4  
1 Introduction TheWigner Villedistribution (WVD) [1 7] hasbeenshowntobeefficientintheestimationofinstanta neousfrequency (IF)ofasignal.BecauseWVDisofbettertime frequencyresolutionandabletolocateen ergybasedontheIFlaw ,especiallyforalinearfre quencymodulated(LFM )signalwithaconstantampli tude,WVDwillreducetoarowofdeltafunctions .ThereforeonecanobtainanunbiasedestimateofIFofthesignalusingthepeakofWVD .Butperformanceofthepeakestimatorisdegradedsignificantlywithesti mationvariance quic…  相似文献   
992.
INTRODUCTION A growing and seemingly insatiable bandwidth demand in the marketplace is bring Free-Space Op- tical (FSO) technology into the carrier space as a means of broadband access for closing the “last mile” connectivity gap throughout metropolitan networks. Terrestrial short-range FSO systems which are gen- erally point-to-point links between buildings on the campus or different buildings of a company can be used to setup wireless communication networks or to supplement radio a…  相似文献   
993.
In this paper, the general exact penalty functions in integer programming were studied. The conditions which ensure the exact penalty property for the general penalty function with one penalty parameter were given and a general penalty function with two parameters was proposed.  相似文献   
994.
Retractions serve as one perspective of the publishing process, and can offer vast insight into the problems associated with basic research, with the traditional publishing platform, or with policies. Some established retraction guidelines exist, such as those established by the Committee on Publication Ethics, or COPE. This essay provides a perspective of stealth or silent retractions within the broader concept of retractions, and within the framework of the COPE retraction guidelines. The issue of opaque retraction notices, especially in the case of COPE members, as well as the prominence of questionable retraction policies among select “predatory” open access publishers, is emphasized. Select clear examples are provided.  相似文献   
995.
In the decades since the Second World War, interest in Western-style children’s books has expanded in tandem with the growth of a literacy-minded global middle class. Now, as publishing for young people takes root for the first time in nations as economically and culturally diverse as Mexico, Saudi Arabia, and China, the opportunities for rights exchanges, co-editions, and other forms of industry cooperation across national and cultural borders are greater than ever.  相似文献   
996.
In Japan, comic plays a leading role in electronic publishing, whereas e-book sales generated from novels are small. This study investigates format choice, such as pocket-sized paperbacks and e-books for popular novels on bestseller lists in 2010. The results show that almost half of novels are not released as e-books and Japanese authors who already have strong sales performances are not positive about releasing e-books, whereas all foreign novels are released as e-books. One reason that electronic publishing other than comics has not developed in Japan may be that many novels written by popular authors are not provided as e-books.  相似文献   
997.
998.
The purpose of this work is to address the changes in the role of the publisher, based on the analysis of the dynamics and performance of the major publishing houses in Argentina today. Based on a number of interviews, we will seek to identify and analyze the tension occurring between the cultural and business logics among stakeholders with a particular interest in the field. These actors share a “publisher’s practical sense” that outlines their habitus and refers to a series of dispositions for action consisting of technical and theoretical knowledge, intuitive processes which, together, make up the publisher’s practice.  相似文献   
999.
1000.
The purpose of this study was to discover whether there are scholarly evaluation metrics that can be applied to a wide range of books’ types and contents. We analyzed over 70,000 books and collected various metrics per each title including traditional and altmetrics measures. The analysis in this paper depicts the top books showing the highest rates of citations, reviews, readership, downloads, twitter and more. Our results show that books display different impact in each of the measurements and vary by types and content. There isn’t one measure that captures the impact of books across the board. We conclude that books should be evaluated by types and contents while using different measures per each.  相似文献   
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