In this paper, we obtain Chen’s inequalities in (k,?μ)-contact space form with a semi-symmetric non-metric connection. Also we obtain the inequalites for Ricci and K-Ricci curvatures.
We carried out a general survey of current situations of P.intermedius S.Y.Chen.Results show that P.intermedius S.Y.Chen is distributed in Dongkeng Township,Jingnan Township and Yanxi Township.It covers an area of 262...We carried out a general survey of current situations of P.intermedius S.Y.Chen.Results show that P.intermedius S.Y.Chen is distributed in Dongkeng Township,Jingnan Township and Yanxi Township.It covers an area of 262.51 hm2.The distribution areas are narrow and limited.What's worse,it suffers from serious destruction and has been withered in large areas.Besides,according to current introduction test,it is difficult to survive in other places.In accordance with Exploring the Criteria for Endangered Categories of Bamboo Species from China put forward by Ma Naixun et al from the Research Institute of Subtropical Forestry of Chinese Academy of Forestry(RISFCAF),we propose incorporating P.intermedius S.Y.Chen into vulnerable species for protection.展开更多
正At the invitation of the parliaments of Italy, Malta, and Cyprus and the Organizing Committee of the Fourth Presidents' Meeting of Israel, Chen Italy: China-Italy relations are developing smoothly. Cultural exch...正At the invitation of the parliaments of Italy, Malta, and Cyprus and the Organizing Committee of the Fourth Presidents' Meeting of Israel, Chen Italy: China-Italy relations are developing smoothly. Cultural exchanges are at the best time ever.展开更多
<span style="font-family:Verdana;">Several authors have used different classical statistical models to fit the Nigerian Bonny Light crude oil price but the application of machine learning models and Fu...<span style="font-family:Verdana;">Several authors have used different classical statistical models to fit the Nigerian Bonny Light crude oil price but the application of machine learning models and Fuzzy Time Series model on the crude oil price has been grossly understudied. Therefore, in this study, a classical statistical model</span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">—</span><span style="font-family:Verdana;">Autoregressive Integrated Moving Average (ARIMA), two machine learning models</span><span style="font-family:Verdana;">—</span><span style="font-family:Verdana;">Artificial Neural Network (ANN) and Random Forest (RF) and Fuzzy Time Series (FTS) Model were compared in modeling the Nigerian Bonny Light crude oil price data for the periods </span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">from</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> January, 2006 to December, 2020. The monthly secondary data were collected from the Nigerian National Petroleum Corporation (NNPC) and Reuters website and divided into train (70%) and test (30%) sets. The train set was used in building the models and the models were validated using the test set. The performance measures used for the comparison include: The modified Diebold-Mariano test, the Root Mean Square Error (RMSE), the Mean Absolute Percentage Error (MAPE) and Nash-Sutcliffe Efficiency (NSE) values. Based on the performance measures, ANN (4, 1, 1) and RF performed better than ARIMA (1, 1, 0) model but FTS model using Chen’s algorithm outperformed every other model. The results recommend the use of FTS model for forecasting future values of the Nigerian Bonny Light Crude oil. However, a hybrid model of ARIMA-ANN or ARIMA-RF should be built and compared with Chen’s algorithm FTS model for the same data set to further verify the power of FTS model using Chen’s algorithm.</span></span></span>展开更多
Singchia Z. J. Liu ＆ L. J. Chen, a new orchid genus, is established based on the new species S. malipoensis Z. J. Liu ＆ L. J. Chen found in southeast Yunnan, China. The new genus is related to Pteroceras, from which...Singchia Z. J. Liu ＆ L. J. Chen, a new orchid genus, is established based on the new species S. malipoensis Z. J. Liu ＆ L. J. Chen found in southeast Yunnan, China. The new genus is related to Pteroceras, from which it differs by having a lip with its basal margins immovably adnate to the lower part of the pendent column foot, a thin-walled spur, and very unequally and deeply split pollinia, each with a distinct caudicle. In addition to a discussion on Ascocentrum pusillum, a species of questionable placement, another new genus, namely Gunnaria S. C. Chen ex Z. J. Liu ＆ L. J. Chen, is set up and a new combination, namely G. pusilla （Aver.） Z. J. Liu ＆ L. J. Chen, is made. The new genus Gunnaria differs from its allyAscocentrum by having a cross-shaped pollinarium, sulcate or split pollinia, each with a distinct caudicle attached to a common linear stipe much longer than either pollinia or viscidium, and strongly incurved side lobes of the lip.展开更多
文摘In this paper, we obtain Chen’s inequalities in (k,?μ)-contact space form with a semi-symmetric non-metric connection. Also we obtain the inequalites for Ricci and K-Ricci curvatures.
文摘We carried out a general survey of current situations of P.intermedius S.Y.Chen.Results show that P.intermedius S.Y.Chen is distributed in Dongkeng Township,Jingnan Township and Yanxi Township.It covers an area of 262.51 hm2.The distribution areas are narrow and limited.What's worse,it suffers from serious destruction and has been withered in large areas.Besides,according to current introduction test,it is difficult to survive in other places.In accordance with Exploring the Criteria for Endangered Categories of Bamboo Species from China put forward by Ma Naixun et al from the Research Institute of Subtropical Forestry of Chinese Academy of Forestry(RISFCAF),we propose incorporating P.intermedius S.Y.Chen into vulnerable species for protection.
文摘正At the invitation of the parliaments of Italy, Malta, and Cyprus and the Organizing Committee of the Fourth Presidents' Meeting of Israel, Chen Italy: China-Italy relations are developing smoothly. Cultural exchanges are at the best time ever.
文摘<span style="font-family:Verdana;">Several authors have used different classical statistical models to fit the Nigerian Bonny Light crude oil price but the application of machine learning models and Fuzzy Time Series model on the crude oil price has been grossly understudied. Therefore, in this study, a classical statistical model</span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">—</span><span style="font-family:Verdana;">Autoregressive Integrated Moving Average (ARIMA), two machine learning models</span><span style="font-family:Verdana;">—</span><span style="font-family:Verdana;">Artificial Neural Network (ANN) and Random Forest (RF) and Fuzzy Time Series (FTS) Model were compared in modeling the Nigerian Bonny Light crude oil price data for the periods </span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">from</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> January, 2006 to December, 2020. The monthly secondary data were collected from the Nigerian National Petroleum Corporation (NNPC) and Reuters website and divided into train (70%) and test (30%) sets. The train set was used in building the models and the models were validated using the test set. The performance measures used for the comparison include: The modified Diebold-Mariano test, the Root Mean Square Error (RMSE), the Mean Absolute Percentage Error (MAPE) and Nash-Sutcliffe Efficiency (NSE) values. Based on the performance measures, ANN (4, 1, 1) and RF performed better than ARIMA (1, 1, 0) model but FTS model using Chen’s algorithm outperformed every other model. The results recommend the use of FTS model for forecasting future values of the Nigerian Bonny Light Crude oil. However, a hybrid model of ARIMA-ANN or ARIMA-RF should be built and compared with Chen’s algorithm FTS model for the same data set to further verify the power of FTS model using Chen’s algorithm.</span></span></span>
基金supported financially by the National Program for Wild Life Conservation and Nature Reserve Construction,China,and by the Science & Technology Plan of Shenzhen,China (SYF 200646408).
文摘Singchia Z. J. Liu ＆ L. J. Chen, a new orchid genus, is established based on the new species S. malipoensis Z. J. Liu ＆ L. J. Chen found in southeast Yunnan, China. The new genus is related to Pteroceras, from which it differs by having a lip with its basal margins immovably adnate to the lower part of the pendent column foot, a thin-walled spur, and very unequally and deeply split pollinia, each with a distinct caudicle. In addition to a discussion on Ascocentrum pusillum, a species of questionable placement, another new genus, namely Gunnaria S. C. Chen ex Z. J. Liu ＆ L. J. Chen, is set up and a new combination, namely G. pusilla （Aver.） Z. J. Liu ＆ L. J. Chen, is made. The new genus Gunnaria differs from its allyAscocentrum by having a cross-shaped pollinarium, sulcate or split pollinia, each with a distinct caudicle attached to a common linear stipe much longer than either pollinia or viscidium, and strongly incurved side lobes of the lip.
