The pulse dynamics of harmonic mode-locking in a dissipative soliton resonance(DSR) region in an erbiumdoped fiber ring laser is investigated at different values of anomalous dispersion. The fiber laser is mode-locked...The pulse dynamics of harmonic mode-locking in a dissipative soliton resonance(DSR) region in an erbiumdoped fiber ring laser is investigated at different values of anomalous dispersion. The fiber laser is mode-locked by a nonlinear polarization rotation technique. By inserting 0–200 m anomalous dispersion single-mode fiber in the laser cavity, the cavity length is changed from 17.3 to 217.3 m, and the corresponding dispersion of the cavity ranges from -0.27 to-4.67 ps^2. The observed results show that the tuning range of repetition rate under a harmonic DSR condition is highly influenced by the cavity dispersion. Furthermore, it is found that, by automatically adjusting their harmonic orders, the lasers can work at certain values of repetition rate, which are independent of the cavity length and dispersion. The pulses at the same repetition rate in different laser configurations have similar properties, demonstrating that each achievable repetition rate represents an operation regime of harmonic DSR lasers.展开更多
A pH dependent reduction in growth, Pigment, ATP content, O,' evolution, carbonfixation, Photosynthetic electron transport system, nutrient uptake (NO,' and NH4+),nitrate reductase, and ATPase activities and i...A pH dependent reduction in growth, Pigment, ATP content, O,' evolution, carbonfixation, Photosynthetic electron transport system, nutrient uptake (NO,' and NH4+),nitrate reductase, and ATPase activities and increase in K+ emux of Chlorella vulgaris wasnoticed following supplementation of Cu and Ni to the culture medium. PS II was foundto be more sensitive to both pH and metals than PS I. Though, nitrate reductase (NR) wasmore sensitive to both PH and metals, the ATPase was however, more sensitive t0 metalsbut less sensitive to acidic pH. Acid PH was found to dst the nutrient (NO,' and NH4+)uptake and nitrate reductase in a non-competitive manner. The inhibition Pnduced by thetest metals alone was of noncompetitive type for NO3' uptake, nitrate reductase andATPase and competitive for NH'+ uptake. Acidity not only inhibited the metabolicvariables directly but also through facilitated uptake of metals and increased membranepermeability. A very low sensitivity of ATPase to acidic pH seems to be resgnsible forthe survival of algae in acid environment.展开更多
Idioms are the essence and gems of human wisdom and an important carrier of national culture. As a special form of language, they play an important role in intercultural communication. Due to the uniqueness of each cu...Idioms are the essence and gems of human wisdom and an important carrier of national culture. As a special form of language, they play an important role in intercultural communication. Due to the uniqueness of each culture, English and Chinese idioms are different in many aspects, values included. The present paper attempts to analyze the different values in English and Chinese idioms from three aspects: dependence vs independence, past-time orientation vs future-time orientation, and harmony vs competition. And the authors hope that it will be of some practical significance in people's intercultural communication.展开更多
In this paper well-conditioning of boundary value problems for systems of second order difference equa-tions is studied.First,a sufficient condition for the existence of a unique bounded solution (for large enough num...In this paper well-conditioning of boundary value problems for systems of second order difference equa-tions is studied.First,a sufficient condition for the existence of a unique bounded solution (for large enough number of steps) of an associated homogeneous system is given.Finally,a sufficient condition for well-condi-tioning,intrinsically related to the problem data is proposed.展开更多
Effective temperature level of stream, namely stream pseudo temperature, is determined by its actual temperature and heat transfer temperature difference contribution value. Heat transfer temperature difference con-tr...Effective temperature level of stream, namely stream pseudo temperature, is determined by its actual temperature and heat transfer temperature difference contribution value. Heat transfer temperature difference con-tribution value of a stream depends on its heat transfer film coefficient, cost per unit heat transfer area, actual tem-perature, and so on. In the determination of the suitable heat transfer temperature difference contribution values of the stream, the total annual cost of multistream heat exchanger network (MSHEN) is regarded as an objective func-tion, and genetic/simulated annealing algorithm (GA/SA) is adopted for optimizing the heat transfer temperature difference contribution values of the stream. The stream pseudo temperatures are subsequently obtained. On the ba-sis of stream pseudo temperature, optimized MSHEN can be attained by the temperature-enthalpy (T-H) diagram method. This approach is characterized with fewer decision variables and higher feasibility of solutions. The calcu-lation efficiency of GA/SA can be remarkably enhanced by this approach and more probability is shown in search-ing the global optimum solution. Hence this approach is presented for solving industrial-sized MSHEN which is difficult to deal by traditional algorithm. Moreover, in the optimization of stream heat transfer temperature differ-ence contribution values, the effects of the stream temperature, the heat transfer film coefficient, and the construc-tion material of heat exchangers are considered, therefore this approach can be used to optimize and design heat exchanger network (HEN) with unequal heat transfer film coefficients and different of construction materials. The performance of the proposed approach has been demonstrated with three examples and the obtained solutions are compared with those available in literatures. The results show that the large-scale MSHEN synthesis problems can be solved to obtain good solutions with the modest computational effort.展开更多
This study aimed to conduct statistical analysis of temperature,relative humidity,wind direction,wind velocity,deep ground temperature and other related data from National Meteorological Observing Station of Hejian Ci...This study aimed to conduct statistical analysis of temperature,relative humidity,wind direction,wind velocity,deep ground temperature and other related data from National Meteorological Observing Station of Hejian City in 2012.According to the results,observation data varied due to different instruments and equipments,surrounding environments and underlying surface properties.The difference value of monthly average temperature between new site and old site ranged from-0.5 to 0 ℃; the difference value of monthly average maximum temperature ranged from-0.4 to 0.2 ℃; the difference value of monthly average minimum temperature ranged from-0.8 to 0 ℃; the difference value of monthly extreme maximum temperature ranged from-1.1 to 0.6 ℃; the difference value of monthly extreme minimum temperature ranged from-1.2 to 0.3 ℃.Annual average temperature,annual average maximum temperature and annual average minimum temperature in new site were lower than those in old site; annual extreme maximum temperature in new site was higher than that in old site; annual extreme minimum temperature in new site was lower than that in old site.The difference value of monthly average relative humidity between new site and old site ranged from 2% to 6%; the difference value of monthly minimum relative humidity ranged from-4% to 5%.Annual minimum relative humidity in new site was consistent with that in old site.The difference value of 2 min average wind velocity between new site and old site ranged from-0.1 to 0.4 m/s; the difference value of monthly maximum wind velocity ranged from-1.2 to 2.2 m/s; the difference value of monthly extreme wind velocity ranged from-2.0 to 2.8 m/s.Annual maximum wind velocity in new site was basically consistent with that in old site; annual extreme wind velocity in new site was significantly higher than that in old site; annual wind direction frequency in new site was lower than that in old site; annual most frequent wind direction in new site was S and that in old site was SSW.The difference value of average temperature at the depth of 40 cm ranged from-1.1 to 2.5 ℃; the difference value of average temperature at the depth of 80 cm ranged from-2.4 to 2.1 ℃; the difference value of average temperature at the depth of 160 cm ranged from-2.5 to 2.7 ℃; the difference value of average temperature at the depth of 320 cm ranged from-1.6 to 1.1 ℃.Annual average temperatures at the depths of 40 and 160 cm in new site were higher than those in old site,while annual average temperatures at the depths of 80 and 320 cm in new site were lower than those in old site.This paper provided certain correction stand for the use of observation data from new and old sites.展开更多
A new method called RS-MSVM (Rough Set and Multi-class Support Vector Machine) is proposed for network intrusion detection. This method is based on rough set followed by MSVM for attribute reduction and classificati...A new method called RS-MSVM (Rough Set and Multi-class Support Vector Machine) is proposed for network intrusion detection. This method is based on rough set followed by MSVM for attribute reduction and classification respectively, The number of attributes of the network data used in this paper is reduced from 41 to 30 using rough set theory. The kernel function of HVDM-RBF (Heterogeneous Value Difference Metric Radial Basis Function), based on the heterogeneous value difference metric of heterogeneous datasets, is constructed for the heterogeneous network data. HVDM-RBF and one-against-one method are applied to build MSVM. DARPA (Defense Advanced Research Projects Agency) intrusion detection evaluating data were used in the experiment. The testing results show that our method outperforms other methods mentioned in this paper on six aspects: detection accuracy, number of support vectors, false positive rate, falsc negative rate, training time and testing time.展开更多
In order to improve the frequency response and anti-interference characteristics of the smart electromechanical actuator(EMA)system,and aiming at the force fighting problem when multiple actuators work synchronously,a...In order to improve the frequency response and anti-interference characteristics of the smart electromechanical actuator(EMA)system,and aiming at the force fighting problem when multiple actuators work synchronously,a multi input multi output(MIMO)position difference cross coupling control coordinated strategy based on double‑closed-loop load feedforward control is proposed and designed.In this strategy,the singular value method of return difference matrix is used to design the parameter range that meets the requirements of system stability margin,and the sensitivity function and the H_(∞)norm theory are used to design and determine the optimal solution in the obtained parameter stability region,so that the multi actuator system has excellent synchronization,stability and anti-interference.At the same time,the mathematical model of the integrated smart EMA system is established.According to the requirements of point-to-point control,the controller of double-loop control and load feedforward compensation is determined and designed to improve the frequency response and anti-interference ability of single actuator.Finally,the 270 V high-voltage smart EMA system experimental platform is built,and the frequency response,load feedforward compensation and coordinated control experiments are carried out to verify the correctness of the position difference cross coupling control strategy and the rationality of the parameter design,so that the system can reach the servo control indexes of bandwidth 6 Hz,the maximum output force 20000 N and the synchronization error≤0.1 mm,which effectively solves the problem of force fighting.展开更多
The value difference metric (VDM) is one of the best-known and widely used distance functions for nominal attributes. This work applies the instance weighting technique to improve VDM. An instance weighted value dif...The value difference metric (VDM) is one of the best-known and widely used distance functions for nominal attributes. This work applies the instance weighting technique to improve VDM. An instance weighted value difference met- ric (IWVDM) is proposed here. Different from prior work, IWVDM uses naive Bayes (NB) to find weights for train- ing instances. Because early work has shown that there is a close relationship between VDM and NB, some work on NB can be applied to VDM. The weight of a training instance x, that belongs to the class c, is assigned according to the dif- ference between the estimated conditional probability P(c/x) by NB and the true conditional probability P(c/x), and the weight is adjusted iteratively. Compared with previous work, IWVDM has the advantage of reducing the time complex- ity of the process of finding weights, and simultaneously im- proving the performance of VDM. Experimental results on 36 UCI datasets validate the effectiveness of IWVDM.展开更多
It is well-known that in order to build a strong ensemble, the component learners should be with high diversity as well as high accuracy. If perturbing the training set can cause significant changes in the component l...It is well-known that in order to build a strong ensemble, the component learners should be with high diversity as well as high accuracy. If perturbing the training set can cause significant changes in the component learners constructed, then Bagging can effectively improve accuracy. However, for stable learners such as nearest neighbor classifiers, perturbing the training set can hardly produce diverse component learners, therefore Bagging does not work well. This paper adapts Bagging to nearest neighbor classifiers through injecting randomness to distance metrics. In constructing the component learners, both the training set and the distance metric employed for identifying the neighbors are perturbed. A large scale empirical study reported in this paper shows that the proposed BagInRand algorithm can effectively improve the accuracy of nearest neighbor classifiers.展开更多
基金National Natural Science Foundation of China(NSFC)(61435003,61421002,61327004,61377042,61505024,61378028)Science and Technology Project of Sichuan Province(2016JY0102)
文摘The pulse dynamics of harmonic mode-locking in a dissipative soliton resonance(DSR) region in an erbiumdoped fiber ring laser is investigated at different values of anomalous dispersion. The fiber laser is mode-locked by a nonlinear polarization rotation technique. By inserting 0–200 m anomalous dispersion single-mode fiber in the laser cavity, the cavity length is changed from 17.3 to 217.3 m, and the corresponding dispersion of the cavity ranges from -0.27 to-4.67 ps^2. The observed results show that the tuning range of repetition rate under a harmonic DSR condition is highly influenced by the cavity dispersion. Furthermore, it is found that, by automatically adjusting their harmonic orders, the lasers can work at certain values of repetition rate, which are independent of the cavity length and dispersion. The pulses at the same repetition rate in different laser configurations have similar properties, demonstrating that each achievable repetition rate represents an operation regime of harmonic DSR lasers.
文摘A pH dependent reduction in growth, Pigment, ATP content, O,' evolution, carbonfixation, Photosynthetic electron transport system, nutrient uptake (NO,' and NH4+),nitrate reductase, and ATPase activities and increase in K+ emux of Chlorella vulgaris wasnoticed following supplementation of Cu and Ni to the culture medium. PS II was foundto be more sensitive to both pH and metals than PS I. Though, nitrate reductase (NR) wasmore sensitive to both PH and metals, the ATPase was however, more sensitive t0 metalsbut less sensitive to acidic pH. Acid PH was found to dst the nutrient (NO,' and NH4+)uptake and nitrate reductase in a non-competitive manner. The inhibition Pnduced by thetest metals alone was of noncompetitive type for NO3' uptake, nitrate reductase andATPase and competitive for NH'+ uptake. Acidity not only inhibited the metabolicvariables directly but also through facilitated uptake of metals and increased membranepermeability. A very low sensitivity of ATPase to acidic pH seems to be resgnsible forthe survival of algae in acid environment.
文摘Idioms are the essence and gems of human wisdom and an important carrier of national culture. As a special form of language, they play an important role in intercultural communication. Due to the uniqueness of each culture, English and Chinese idioms are different in many aspects, values included. The present paper attempts to analyze the different values in English and Chinese idioms from three aspects: dependence vs independence, past-time orientation vs future-time orientation, and harmony vs competition. And the authors hope that it will be of some practical significance in people's intercultural communication.
基金This work has been partially supported by the "Generalitat Valenciana" grant GV1118/93the Spanish D. G. I. C. Y.T. grant PB93-0381
文摘In this paper well-conditioning of boundary value problems for systems of second order difference equa-tions is studied.First,a sufficient condition for the existence of a unique bounded solution (for large enough number of steps) of an associated homogeneous system is given.Finally,a sufficient condition for well-condi-tioning,intrinsically related to the problem data is proposed.
基金Supported by the Deutsche Forschungsgemeinschaft (DFG No.RO 294/9).
文摘Effective temperature level of stream, namely stream pseudo temperature, is determined by its actual temperature and heat transfer temperature difference contribution value. Heat transfer temperature difference con-tribution value of a stream depends on its heat transfer film coefficient, cost per unit heat transfer area, actual tem-perature, and so on. In the determination of the suitable heat transfer temperature difference contribution values of the stream, the total annual cost of multistream heat exchanger network (MSHEN) is regarded as an objective func-tion, and genetic/simulated annealing algorithm (GA/SA) is adopted for optimizing the heat transfer temperature difference contribution values of the stream. The stream pseudo temperatures are subsequently obtained. On the ba-sis of stream pseudo temperature, optimized MSHEN can be attained by the temperature-enthalpy (T-H) diagram method. This approach is characterized with fewer decision variables and higher feasibility of solutions. The calcu-lation efficiency of GA/SA can be remarkably enhanced by this approach and more probability is shown in search-ing the global optimum solution. Hence this approach is presented for solving industrial-sized MSHEN which is difficult to deal by traditional algorithm. Moreover, in the optimization of stream heat transfer temperature differ-ence contribution values, the effects of the stream temperature, the heat transfer film coefficient, and the construc-tion material of heat exchangers are considered, therefore this approach can be used to optimize and design heat exchanger network (HEN) with unequal heat transfer film coefficients and different of construction materials. The performance of the proposed approach has been demonstrated with three examples and the obtained solutions are compared with those available in literatures. The results show that the large-scale MSHEN synthesis problems can be solved to obtain good solutions with the modest computational effort.
文摘This study aimed to conduct statistical analysis of temperature,relative humidity,wind direction,wind velocity,deep ground temperature and other related data from National Meteorological Observing Station of Hejian City in 2012.According to the results,observation data varied due to different instruments and equipments,surrounding environments and underlying surface properties.The difference value of monthly average temperature between new site and old site ranged from-0.5 to 0 ℃; the difference value of monthly average maximum temperature ranged from-0.4 to 0.2 ℃; the difference value of monthly average minimum temperature ranged from-0.8 to 0 ℃; the difference value of monthly extreme maximum temperature ranged from-1.1 to 0.6 ℃; the difference value of monthly extreme minimum temperature ranged from-1.2 to 0.3 ℃.Annual average temperature,annual average maximum temperature and annual average minimum temperature in new site were lower than those in old site; annual extreme maximum temperature in new site was higher than that in old site; annual extreme minimum temperature in new site was lower than that in old site.The difference value of monthly average relative humidity between new site and old site ranged from 2% to 6%; the difference value of monthly minimum relative humidity ranged from-4% to 5%.Annual minimum relative humidity in new site was consistent with that in old site.The difference value of 2 min average wind velocity between new site and old site ranged from-0.1 to 0.4 m/s; the difference value of monthly maximum wind velocity ranged from-1.2 to 2.2 m/s; the difference value of monthly extreme wind velocity ranged from-2.0 to 2.8 m/s.Annual maximum wind velocity in new site was basically consistent with that in old site; annual extreme wind velocity in new site was significantly higher than that in old site; annual wind direction frequency in new site was lower than that in old site; annual most frequent wind direction in new site was S and that in old site was SSW.The difference value of average temperature at the depth of 40 cm ranged from-1.1 to 2.5 ℃; the difference value of average temperature at the depth of 80 cm ranged from-2.4 to 2.1 ℃; the difference value of average temperature at the depth of 160 cm ranged from-2.5 to 2.7 ℃; the difference value of average temperature at the depth of 320 cm ranged from-1.6 to 1.1 ℃.Annual average temperatures at the depths of 40 and 160 cm in new site were higher than those in old site,while annual average temperatures at the depths of 80 and 320 cm in new site were lower than those in old site.This paper provided certain correction stand for the use of observation data from new and old sites.
基金Supported by the 863 High Tech. Project (2001AA140213) and the State Key Basic Research Pro-ject (2001CB309403).
文摘A new method called RS-MSVM (Rough Set and Multi-class Support Vector Machine) is proposed for network intrusion detection. This method is based on rough set followed by MSVM for attribute reduction and classification respectively, The number of attributes of the network data used in this paper is reduced from 41 to 30 using rough set theory. The kernel function of HVDM-RBF (Heterogeneous Value Difference Metric Radial Basis Function), based on the heterogeneous value difference metric of heterogeneous datasets, is constructed for the heterogeneous network data. HVDM-RBF and one-against-one method are applied to build MSVM. DARPA (Defense Advanced Research Projects Agency) intrusion detection evaluating data were used in the experiment. The testing results show that our method outperforms other methods mentioned in this paper on six aspects: detection accuracy, number of support vectors, false positive rate, falsc negative rate, training time and testing time.
基金supported by the National Natural Science Foundation of China(No.52077100)the Aviation Science Foundation(No.201958052001)
文摘In order to improve the frequency response and anti-interference characteristics of the smart electromechanical actuator(EMA)system,and aiming at the force fighting problem when multiple actuators work synchronously,a multi input multi output(MIMO)position difference cross coupling control coordinated strategy based on double‑closed-loop load feedforward control is proposed and designed.In this strategy,the singular value method of return difference matrix is used to design the parameter range that meets the requirements of system stability margin,and the sensitivity function and the H_(∞)norm theory are used to design and determine the optimal solution in the obtained parameter stability region,so that the multi actuator system has excellent synchronization,stability and anti-interference.At the same time,the mathematical model of the integrated smart EMA system is established.According to the requirements of point-to-point control,the controller of double-loop control and load feedforward compensation is determined and designed to improve the frequency response and anti-interference ability of single actuator.Finally,the 270 V high-voltage smart EMA system experimental platform is built,and the frequency response,load feedforward compensation and coordinated control experiments are carried out to verify the correctness of the position difference cross coupling control strategy and the rationality of the parameter design,so that the system can reach the servo control indexes of bandwidth 6 Hz,the maximum output force 20000 N and the synchronization error≤0.1 mm,which effectively solves the problem of force fighting.
文摘The value difference metric (VDM) is one of the best-known and widely used distance functions for nominal attributes. This work applies the instance weighting technique to improve VDM. An instance weighted value difference met- ric (IWVDM) is proposed here. Different from prior work, IWVDM uses naive Bayes (NB) to find weights for train- ing instances. Because early work has shown that there is a close relationship between VDM and NB, some work on NB can be applied to VDM. The weight of a training instance x, that belongs to the class c, is assigned according to the dif- ference between the estimated conditional probability P(c/x) by NB and the true conditional probability P(c/x), and the weight is adjusted iteratively. Compared with previous work, IWVDM has the advantage of reducing the time complex- ity of the process of finding weights, and simultaneously im- proving the performance of VDM. Experimental results on 36 UCI datasets validate the effectiveness of IWVDM.
文摘It is well-known that in order to build a strong ensemble, the component learners should be with high diversity as well as high accuracy. If perturbing the training set can cause significant changes in the component learners constructed, then Bagging can effectively improve accuracy. However, for stable learners such as nearest neighbor classifiers, perturbing the training set can hardly produce diverse component learners, therefore Bagging does not work well. This paper adapts Bagging to nearest neighbor classifiers through injecting randomness to distance metrics. In constructing the component learners, both the training set and the distance metric employed for identifying the neighbors are perturbed. A large scale empirical study reported in this paper shows that the proposed BagInRand algorithm can effectively improve the accuracy of nearest neighbor classifiers.