In the extension matrix approach of inductive learning, the minimum formula (MFL) ofa positive example (e^+) against a set of negative examples (NE) and tbe optimal covering(MCV) of a set of positive examples (PE) aga...In the extension matrix approach of inductive learning, the minimum formula (MFL) ofa positive example (e^+) against a set of negative examples (NE) and tbe optimal covering(MCV) of a set of positive examples (PE) against NE are two striking optimization prob-lems. They have been proved to be NP-hard in Ref. [1]. This paper presents four algorithms,named MFL, HFL, MCV and HCV respectively. Algorithms MFL and MCV are complete forsolving the problems MFL and MCV but they opelate in exponential time on the number ofattributes in an example space and polynomial time on the number of examples. AlgorithmsHFL and HCV are two heuristic algorithms homologous to Algorithms MFL and MCV buttheir time complexities are polynomial.展开更多
Knowing the time extension degree of full mortality in phosphine fumigation at low temperature significantly contributes to successful insect pest control,especially for reducing fumigation failure and inhibiting resi...Knowing the time extension degree of full mortality in phosphine fumigation at low temperature significantly contributes to successful insect pest control,especially for reducing fumigation failure and inhibiting resistance development.The comparison ofmortality and lethal time on eggs,larvae,pupae and adults of Cryptolestes ferrugineus(Stephens)was conducted,and the strain with 1043 times of resistance factor to phosphine was assayed during fumigation with 300 mL/m^3 of phosphine concentration at 18,23 and 28℃.The LT50 values to eggs,larvae,pupae and adults of C.ferrugineus at 18℃ were postponed by 2,2,1 and 5 d comparedwith that at 23℃,and 5,4,5 and 7 d compared with that at 28℃,respectively.The LT99 values to eggs,larvae,pupae and adults at 18℃ were 5,1,2 and 7 d longer than that at 23℃,and 6,5,5 and 10 d longer than that at 28℃,respectively.The lethal time of different life stages of the C.ferrugineus strain significantly increased with temperature decreasing.The exposure time of full mortality on pupae at 300 mL/m^3 of phosphine at 18℃ reached 38 d,which was 12 d longer than that of larvae.The order of tolerance of different life stages of C.ferrugineus exposed to 300 mL/m^3 phosphine from high to low was pupae,eggs,adults,larvae at tested temperatures.展开更多
Multiple wireless access technology has been embedded into a single mobile device as a fundamental feature, aiming to give end users ubiquitous access at any time. To allow the users to enjoy the ubiquitous connectivi...Multiple wireless access technology has been embedded into a single mobile device as a fundamental feature, aiming to give end users ubiquitous access at any time. To allow the users to enjoy the ubiquitous connectivity, the mobile device has to consume higher energy for the simultaneous activation of multiple wireless interface and the continuous connectivity. In addition, a seamless vertical handover between the access technologies is a mandatory requirement to insure the quality, reliability and continuity of real time services. In this paper, the continuity of real time services as well as energy saving for mobile devices has been taken into account. The conceptual idea is that whenever traffic rate is lower than a threshold it will be smoothly handed over to a low energy consumption technology, i.e., Bluetooth. When the traffic exceeds the limitation of Bluetooth bandwidth, it will be handed over to a wider bandwidth technology, i.e., Wi-Fi. In the considered scenarios, the technologies are not interconnected;hence, the vertical handover management must be fully controlled by the mobile devices. The performance of the system including energy saving and maintaining the continuity of real time services has been evaluated by direct measurements in a real testbed.展开更多
In this paper,time extension methods,originally designed for clear-sky land surface conditions,are used to estimate high-spatial resolution surface daily longwave(LW)radiation from the instantaneous Global LAnd Surfac...In this paper,time extension methods,originally designed for clear-sky land surface conditions,are used to estimate high-spatial resolution surface daily longwave(LW)radiation from the instantaneous Global LAnd Surface Satellite(GLASS)longwave radiation product.The performance of four time methods were first tested by using ground based flux measurements that were collected from 141 global sites.Combined with the accuracy of daily LW radiation estimated from the instantaneous GLASS LW radiation,the linear sine interpolation method performs better than the other methods and was employed to estimate the daily LW radiation as follows:The bias/Root Mean Square Error(RMSE)of the linear sine interpolation method were−6.30/15.10 W/m^(2)for the daily longwave upward radiation(LWUP),−1.65/27.63 W/m2 for the daily longwave downward radiation(LWDN),and 4.69/26.42 W/m^(2)for the daily net longwave radiation(LWNR).We found that the lengths of the diurnal cycle of LW radiation are longer than the durations between sunrise and sunset and we proposed increasing the day length by 1.5 h.The accuracies of daily LW radiation were improved after adjusting the day length.The bias/RMSE were−4.15/13.74 W/m2 for the daily LWUP,−1.3/27.52 W/m^(2)for the daily LWDN,and 2.85/25.91 W/m^(2)for the daily LWNR.We are producing long-term surface daily LW radiation values from the GLASS LW radiation product.展开更多
基金Project supported by the National Natural Science Foundation of China.
文摘In the extension matrix approach of inductive learning, the minimum formula (MFL) ofa positive example (e^+) against a set of negative examples (NE) and tbe optimal covering(MCV) of a set of positive examples (PE) against NE are two striking optimization prob-lems. They have been proved to be NP-hard in Ref. [1]. This paper presents four algorithms,named MFL, HFL, MCV and HCV respectively. Algorithms MFL and MCV are complete forsolving the problems MFL and MCV but they opelate in exponential time on the number ofattributes in an example space and polynomial time on the number of examples. AlgorithmsHFL and HCV are two heuristic algorithms homologous to Algorithms MFL and MCV buttheir time complexities are polynomial.
基金This work was supported by National Key Research and Development Program of the 13th Five-Year Plan(No.2017YFC1600800).
文摘Knowing the time extension degree of full mortality in phosphine fumigation at low temperature significantly contributes to successful insect pest control,especially for reducing fumigation failure and inhibiting resistance development.The comparison ofmortality and lethal time on eggs,larvae,pupae and adults of Cryptolestes ferrugineus(Stephens)was conducted,and the strain with 1043 times of resistance factor to phosphine was assayed during fumigation with 300 mL/m^3 of phosphine concentration at 18,23 and 28℃.The LT50 values to eggs,larvae,pupae and adults of C.ferrugineus at 18℃ were postponed by 2,2,1 and 5 d comparedwith that at 23℃,and 5,4,5 and 7 d compared with that at 28℃,respectively.The LT99 values to eggs,larvae,pupae and adults at 18℃ were 5,1,2 and 7 d longer than that at 23℃,and 6,5,5 and 10 d longer than that at 28℃,respectively.The lethal time of different life stages of the C.ferrugineus strain significantly increased with temperature decreasing.The exposure time of full mortality on pupae at 300 mL/m^3 of phosphine at 18℃ reached 38 d,which was 12 d longer than that of larvae.The order of tolerance of different life stages of C.ferrugineus exposed to 300 mL/m^3 phosphine from high to low was pupae,eggs,adults,larvae at tested temperatures.
文摘Multiple wireless access technology has been embedded into a single mobile device as a fundamental feature, aiming to give end users ubiquitous access at any time. To allow the users to enjoy the ubiquitous connectivity, the mobile device has to consume higher energy for the simultaneous activation of multiple wireless interface and the continuous connectivity. In addition, a seamless vertical handover between the access technologies is a mandatory requirement to insure the quality, reliability and continuity of real time services. In this paper, the continuity of real time services as well as energy saving for mobile devices has been taken into account. The conceptual idea is that whenever traffic rate is lower than a threshold it will be smoothly handed over to a low energy consumption technology, i.e., Bluetooth. When the traffic exceeds the limitation of Bluetooth bandwidth, it will be handed over to a wider bandwidth technology, i.e., Wi-Fi. In the considered scenarios, the technologies are not interconnected;hence, the vertical handover management must be fully controlled by the mobile devices. The performance of the system including energy saving and maintaining the continuity of real time services has been evaluated by direct measurements in a real testbed.
基金supported by the National Key Research and Development Program of China under Grant 2016YFA0600101National Natural Science Foundation of China via grants 42090011,41771365 and 42071308the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)under Grant 2019QZKK0206.
文摘In this paper,time extension methods,originally designed for clear-sky land surface conditions,are used to estimate high-spatial resolution surface daily longwave(LW)radiation from the instantaneous Global LAnd Surface Satellite(GLASS)longwave radiation product.The performance of four time methods were first tested by using ground based flux measurements that were collected from 141 global sites.Combined with the accuracy of daily LW radiation estimated from the instantaneous GLASS LW radiation,the linear sine interpolation method performs better than the other methods and was employed to estimate the daily LW radiation as follows:The bias/Root Mean Square Error(RMSE)of the linear sine interpolation method were−6.30/15.10 W/m^(2)for the daily longwave upward radiation(LWUP),−1.65/27.63 W/m2 for the daily longwave downward radiation(LWDN),and 4.69/26.42 W/m^(2)for the daily net longwave radiation(LWNR).We found that the lengths of the diurnal cycle of LW radiation are longer than the durations between sunrise and sunset and we proposed increasing the day length by 1.5 h.The accuracies of daily LW radiation were improved after adjusting the day length.The bias/RMSE were−4.15/13.74 W/m2 for the daily LWUP,−1.3/27.52 W/m^(2)for the daily LWDN,and 2.85/25.91 W/m^(2)for the daily LWNR.We are producing long-term surface daily LW radiation values from the GLASS LW radiation product.
