We investigate the average Level Crossing Rate （LCR） and Average Fading Duration （AFD） of multiuser single relay co- operation wireless uplinks over independent and non-identically distributed （i.ni.d） Ray- leig...We investigate the average Level Crossing Rate （LCR） and Average Fading Duration （AFD） of multiuser single relay co- operation wireless uplinks over independent and non-identically distributed （i.ni.d） Ray- leigh fading channels. We first present the statistical analyses of the first-hop equivalent envelope. Then, we investigate the LCR and AFD of an equivalent end-to-end envelope, and present the closed-form solutions to LCR and AFD, which are given with integral forms. Finally, we derive the Laplace approximations of LCR and AFD as well as the upper and lower bounds. The numerical results of LCR show that the upper bound is tight. For multi user systems with different number of mobile users, the analyses indicate that the LCRs are approximately the same at the low level of the envelope. envelope However, there are at the high level of the reasonable differences among the curves of LCRs. Due to that fact that AFD is the inverse function of LCR, the results for AFD are the opposite.展开更多
The proposed model considers the products with finite shelf-life which causes a small amount of decay. The market demand is assumed to be level dependent and in a linear form. The model has also considered the constan...The proposed model considers the products with finite shelf-life which causes a small amount of decay. The market demand is assumed to be level dependent and in a linear form. The model has also considered the constant production rate which stops attaining a desired level of inventories and that is the highest level of inventories. Production starts with a buffer stock and without any sort of backlogs. Due to the market demand and product’s decay, the inventory reduces to the level of buffer stock where again the production cycle starts. With a numerical search procedure the proof of the proposed model has been shown. The objective of the model is to obtain the total average optimum inventory cost and optimum ordering cycle.展开更多
An analytics method of predicting the annual variation rate (AVR) of global sea-level (GSL) is developed.Through the calculation by using the mean sea-level data collected from the tidal gauge stations over the world,...An analytics method of predicting the annual variation rate (AVR) of global sea-level (GSL) is developed.Through the calculation by using the mean sea-level data collected from the tidal gauge stations over the world, a GSL rise of 0. 15～0. 16 cm/a is obtained. The predicted values of AVR of GSL for the 21st century are presented. The authors' results have been compared to those reported by other scientists at home and abroad. The method proposedhere is more convenient and precise.展开更多
Rack-level loop thermosyphons have been widely adopted as a solution to data centers’growing energy demands.While numerous studies have highlighted the heat transfer performance and energy-saving benefits of this sys...Rack-level loop thermosyphons have been widely adopted as a solution to data centers’growing energy demands.While numerous studies have highlighted the heat transfer performance and energy-saving benefits of this system,its economic feasibility,water usage effectiveness(WUE),and carbon usage effectiveness(CUE)remain underexplored.This study introduces a comprehensive evaluation index designed to assess the applicability of the rack-level loop thermosyphon system across various computing hub nodes.The air wet bulb temperature Ta,w was identified as the most significant factor influencing the variability in the combination of PUE,CUE,and WUE values.The results indicate that the rack-level loop thermosyphon system achieves the highest score in Lanzhou(94.485)and the lowest in Beijing(89.261)based on the comprehensive evaluation index.The overall ranking of cities according to the comprehensive evaluation score is as follows:Gansu hub(Lanzhou)>Inner Mongolia hub(Hohhot)>Ningxia hub(Yinchuan)>Yangtze River Delta hub(Shanghai)>Chengdu Chongqing hub(Chongqing)>Guangdong-Hong Kong-Macao Greater Bay Area hub(Guangzhou)>Guizhou hub(Guiyang)>Beijing-Tianjin-Hebei hub(Beijing).Furthermore,Hohhot,Lanzhou,and Yinchuan consistently rank among the top three cities for comprehensive scores across all load rates,while Guiyang(at a 25%load rate),Guangzhou(at a 50%load rate),and Beijing(at 75%and 100%load rates)exhibited the lowest comprehensive scores.展开更多
Based on a large number of actual data, the author believe that the modem global warming and sea level rise resulted from climate warming after the cold front of the Little Ice Age about 200 years ago and the developm...Based on a large number of actual data, the author believe that the modem global warming and sea level rise resulted from climate warming after the cold front of the Little Ice Age about 200 years ago and the developmnet of the sea level rise phase. In the past 30 years, the rate of sea level rise was increasing, which is under the background of the average temperature uplift 0.2F°（0.11℃）every 10 years in succession from the 1980s to the past 10 years this century. On the basis of the absolute and relative sea-level rise rate that was calculated from the tidal data during the same period at home and abroad in the last 30 years, in accordance with the resolutions of the 2010 climate conference in Cancun, at the same time, considering the previous prediction and research, the world＇s sea levels and the relative sea level in Tianjin, Shanghai, Dongying, Xiamen, Haikou and other coastal cities that have severe land subsidence in 2050 and 2100 are calculated and evaluated.展开更多
The main task of sows is to breed piglets. The reproductive performance of sows is different due to different techniques adopted in the production of pig farms, which determines the utilization rate of sows and the nu...The main task of sows is to breed piglets. The reproductive performance of sows is different due to different techniques adopted in the production of pig farms, which determines the utilization rate of sows and the number of sows in the pig farms. The article analyzed the reproductive performance of sows from the technical point of view, so that the utilization rate of sows can be paid enough attention in the production of pig farms.It is suggested that the technical training should be strengthened in pig farms to improve the corresponding technical level. Meanwhile, pig farms should make the full use of reproductive performance of sows to obtain the maximum economic benefit.展开更多
基金supported by the Natural Science Foundation of China under Grant No.61261015the 973 Project under Grant No.2013CB329104+4 种基金the National Natural Science Foundation of China under Grants No. 61071090,No. 61171093the Key Projects under GrantsNo. 2011ZX03005-004-003, No. BK2011027the China Postdoctoral Science Foundation under Grant No. 2012M521105Research Fund for the Doctoral Program of Higher Educationof China under Grant No. 20113223110001the project 11KJA510001 and PAPD
文摘We investigate the average Level Crossing Rate （LCR） and Average Fading Duration （AFD） of multiuser single relay co- operation wireless uplinks over independent and non-identically distributed （i.ni.d） Ray- leigh fading channels. We first present the statistical analyses of the first-hop equivalent envelope. Then, we investigate the LCR and AFD of an equivalent end-to-end envelope, and present the closed-form solutions to LCR and AFD, which are given with integral forms. Finally, we derive the Laplace approximations of LCR and AFD as well as the upper and lower bounds. The numerical results of LCR show that the upper bound is tight. For multi user systems with different number of mobile users, the analyses indicate that the LCRs are approximately the same at the low level of the envelope. envelope However, there are at the high level of the reasonable differences among the curves of LCRs. Due to that fact that AFD is the inverse function of LCR, the results for AFD are the opposite.
文摘The proposed model considers the products with finite shelf-life which causes a small amount of decay. The market demand is assumed to be level dependent and in a linear form. The model has also considered the constant production rate which stops attaining a desired level of inventories and that is the highest level of inventories. Production starts with a buffer stock and without any sort of backlogs. Due to the market demand and product’s decay, the inventory reduces to the level of buffer stock where again the production cycle starts. With a numerical search procedure the proof of the proposed model has been shown. The objective of the model is to obtain the total average optimum inventory cost and optimum ordering cycle.
文摘An analytics method of predicting the annual variation rate (AVR) of global sea-level (GSL) is developed.Through the calculation by using the mean sea-level data collected from the tidal gauge stations over the world, a GSL rise of 0. 15～0. 16 cm/a is obtained. The predicted values of AVR of GSL for the 21st century are presented. The authors' results have been compared to those reported by other scientists at home and abroad. The method proposedhere is more convenient and precise.
基金supported by the Natural Science Foundation of Hunan Province,China(Grant Nos.2023JJ50178 and 2023JJ50194)the Excellent Youth Project of Hunan Provincial Department of Education(Grant No.23B0542).
文摘Rack-level loop thermosyphons have been widely adopted as a solution to data centers’growing energy demands.While numerous studies have highlighted the heat transfer performance and energy-saving benefits of this system,its economic feasibility,water usage effectiveness(WUE),and carbon usage effectiveness(CUE)remain underexplored.This study introduces a comprehensive evaluation index designed to assess the applicability of the rack-level loop thermosyphon system across various computing hub nodes.The air wet bulb temperature Ta,w was identified as the most significant factor influencing the variability in the combination of PUE,CUE,and WUE values.The results indicate that the rack-level loop thermosyphon system achieves the highest score in Lanzhou(94.485)and the lowest in Beijing(89.261)based on the comprehensive evaluation index.The overall ranking of cities according to the comprehensive evaluation score is as follows:Gansu hub(Lanzhou)>Inner Mongolia hub(Hohhot)>Ningxia hub(Yinchuan)>Yangtze River Delta hub(Shanghai)>Chengdu Chongqing hub(Chongqing)>Guangdong-Hong Kong-Macao Greater Bay Area hub(Guangzhou)>Guizhou hub(Guiyang)>Beijing-Tianjin-Hebei hub(Beijing).Furthermore,Hohhot,Lanzhou,and Yinchuan consistently rank among the top three cities for comprehensive scores across all load rates,while Guiyang(at a 25%load rate),Guangzhou(at a 50%load rate),and Beijing(at 75%and 100%load rates)exhibited the lowest comprehensive scores.
基金supported by the National Natural Science Foundation of China (No.40940025)Natural Science Fund of Tianjin (No.07ZCGYSF02400 and 09JCYBJC07400)+2 种基金National ‘973’ Project (No.2007CB411807)State Oceanic Administration of the marine atmosphere-Chemistry and global change open fund of Key Laboratory (No.GCMAC0806)the National Natural Science Fund(No.41006002)
文摘Based on a large number of actual data, the author believe that the modem global warming and sea level rise resulted from climate warming after the cold front of the Little Ice Age about 200 years ago and the developmnet of the sea level rise phase. In the past 30 years, the rate of sea level rise was increasing, which is under the background of the average temperature uplift 0.2F°（0.11℃）every 10 years in succession from the 1980s to the past 10 years this century. On the basis of the absolute and relative sea-level rise rate that was calculated from the tidal data during the same period at home and abroad in the last 30 years, in accordance with the resolutions of the 2010 climate conference in Cancun, at the same time, considering the previous prediction and research, the world＇s sea levels and the relative sea level in Tianjin, Shanghai, Dongying, Xiamen, Haikou and other coastal cities that have severe land subsidence in 2050 and 2100 are calculated and evaluated.
基金Supported by National Natural Science Foundation of China(31760660)
文摘The main task of sows is to breed piglets. The reproductive performance of sows is different due to different techniques adopted in the production of pig farms, which determines the utilization rate of sows and the number of sows in the pig farms. The article analyzed the reproductive performance of sows from the technical point of view, so that the utilization rate of sows can be paid enough attention in the production of pig farms.It is suggested that the technical training should be strengthened in pig farms to improve the corresponding technical level. Meanwhile, pig farms should make the full use of reproductive performance of sows to obtain the maximum economic benefit.
