In this paper, we establish a complete convergence result and a complete moment convergence result for weighted sums of widely orthant dependent random variables under mild conditions. As corollaries, the correspondin...In this paper, we establish a complete convergence result and a complete moment convergence result for weighted sums of widely orthant dependent random variables under mild conditions. As corollaries, the corresponding results for weighted sums of extended negatively orthant dependent random variables are also obtained, which generalize and improve the related known works in the literature.展开更多
Objective To investigate the expressions of cyclin E, cyclin dependent kinase 2(CDK-2)and cyclin-dependent kinase inhibitor p57 KIP2 in human gastric cancer, and to evaluate the relationships between protein level...Objective To investigate the expressions of cyclin E, cyclin dependent kinase 2(CDK-2)and cyclin-dependent kinase inhibitor p57 KIP2 in human gastric cancer, and to evaluate the relationships between protein levels and clinicopathological parameters. Methods Western blot was used to measure the expressions of cyclin E, CDK-2 and p57 KIP2 proteins in the surgically resected gastric carcinoma, adjacent normal mucosa and metastatic lymph nodes from 36 patients. Results Cyclin E and CDK-2 protein levels were higher in gastric cancer tissues in comparison with normal tissues (P<0.05). Overexpression of cyclin E was correlated with lymph node involvement, poor histological grade and serosa invasion (P<0.05). Overexpression of CDK-2 was correlated with lymph nodes involvement (P<0.05). No statistically significant difference between cyclin E and CDK-2 expression was found when samples were stratified according to tumor size (P>0.05). Expression of cyclin E and CDK-2 showed a positive linear correlation (r=0.451, P=0.01). Protein levels of p57 KIP2 were lower in gastric cancer tissues than in the normal mucosa (P<0.05). Decreased expression of p57 KIP2 was correlated with lymph node involvement (P<0.05). No statistically significant difference in p57 KIP2 expression was found when sample were stratified according to tumor size, histological grade or serosa invasion (P>0.05). In metastatic lymph nodes, expression of cyclin E was increased and the expression of p57 KIP2 decreased. Conclusion Overexpressions of cyclin E, CDK-2 and downregulated expression of p57 KIP2 may play important roles in tumorigenesis and metastatic potential of gastric cancer.展开更多
In any multi-cellular organism, the balance between cell division and cell death maintains a constant cell number. Both cell division cycle and cell death are highly regulated events. Whether the cell will proceed thr...In any multi-cellular organism, the balance between cell division and cell death maintains a constant cell number. Both cell division cycle and cell death are highly regulated events. Whether the cell will proceed through the cycle or not, depends upon whether the conditions required at the checkpoints during the cycle are fulfilled. In higher eucaryotic cells, such as mammalian cells, signals that arrest the cycle usually act at a G1 checkpoint. Cells that pass this restriction point are committed to complete the cycle. Regulation of the GI phase of the cell cycle is extremely complex and involves many different families of proteins such as retinoblastoma family cyclin dependent kinases, cyclins, and cyclic kinase inhibitors.展开更多
目的研究体外人骨髓间充质干细胞(MSCs)和汗腺细胞(SGCs)直接和间接共培养条件下骨髓间充质干细胞的表型转化及其机制。方法体外分别分离培养、扩增并鉴定MSCs和汗腺细胞。将培养的MSCs和经47℃高温处理造成热休克的SGCs直接和间接共培...目的研究体外人骨髓间充质干细胞(MSCs)和汗腺细胞(SGCs)直接和间接共培养条件下骨髓间充质干细胞的表型转化及其机制。方法体外分别分离培养、扩增并鉴定MSCs和汗腺细胞。将培养的MSCs和经47℃高温处理造成热休克的SGCs直接和间接共培养,1周后,采用免疫细胞化学染色法和流式细胞仪法检测共培养体系中MSCs的表型改变,W estern b lot测定细胞外信号调节激酶(ERK)和磷酸化细胞外信号调节激酶(pERK)表达。结果MSCs和SGCs均呈克隆样生长,MSCs表达CD44、CD105和CD29,不表达CD34、CEA、CK19和CK7;SGCs表达CEA、CK19、CK8和CK7。MSCs与经高温损伤后的SGCs共培养1周后,部分MSCs呈汗腺细胞表型,间接共培养结果示各组MSCs均表达水平相当的ERK,但pERK水平表达不同。结论成人MSCs和热休克的SGCs直接和间接共培养均可诱导MSCs向SGCs表型转化,pERK途径参与这一过程。展开更多
For the widely orthant dependent （WOD） structure, this paper mainly investigates the precise large deviations for the partial sums of WOD and non-identically distributed random variables with dominatedly varying tai...For the widely orthant dependent （WOD） structure, this paper mainly investigates the precise large deviations for the partial sums of WOD and non-identically distributed random variables with dominatedly varying tails. The obtained results extend some corresponding results.展开更多
AIM: To examine the role of p38 during acute experimental cerulein pancreatitis. METHODS: Rats were treated with cerulein with or without a specific JNK inhibitor (CEP1347) and/or a specific p38 inhibitor (SB203580) a...AIM: To examine the role of p38 during acute experimental cerulein pancreatitis. METHODS: Rats were treated with cerulein with or without a specific JNK inhibitor (CEP1347) and/or a specific p38 inhibitor (SB203580) and pancreatic stress kinase activity was determined. Parameters to assess pancreatitis included trypsin, amylase, lipase, pancreatic weight and histology. RESULTS: JNK inhibition with CEP1347 ameliorated pancreatitis, reducing pancreatic edema. In contrast, p38 inhibition with SB203580 aggravated pancreatitis with higher trypsin levels and, with induction of acinar necrosis not normally found after cerulein hyperstimulation. Simultaneous treatment with both CEP1347 and SB203580 mutually abolished the effects of either compound on cerulein pancreatitis. CONCLUSION: Stress kinases modulate pancreatitis differentially. JNK seems to promote pancreatitis development, possibly by supporting inflammatory reactions such as edema formation while its inhibition ameliorates pancreatitis. In contrast, p38 may help reduce organ destruction while inhibition of p38 during induction of cerulein pancreatitis leads to the occurrence of acinar necrosis.展开更多
In this paper, Kolmogorov-type inequality for negatively superadditive dependent （NSD） random variables is established. By using this inequality, we obtain the almost sure convergence for NSD sequences, which extend...In this paper, Kolmogorov-type inequality for negatively superadditive dependent （NSD） random variables is established. By using this inequality, we obtain the almost sure convergence for NSD sequences, which extends the corresponding results for independent sequences and negatively associated （NA） sequences. In addition, the strong stability for weighted sums of NSD random variables is studied.展开更多
The residential energy scheduling of solar energy is an important research area of smart grid. On the demand side, factors such as household loads, storage batteries, the outside public utility grid and renewable ener...The residential energy scheduling of solar energy is an important research area of smart grid. On the demand side, factors such as household loads, storage batteries, the outside public utility grid and renewable energy resources, are combined together as a nonlinear, time-varying, indefinite and complex system, which is difficult to manage or optimize. Many nations have already applied the residential real-time pricing to balance the burden on their grid. In order to enhance electricity efficiency of the residential micro grid, this paper presents an action dependent heuristic dynamic programming(ADHDP) method to solve the residential energy scheduling problem. The highlights of this paper are listed below. First,the weather-type classification is adopted to establish three types of programming models based on the features of the solar energy. In addition, the priorities of different energy resources are set to reduce the loss of electrical energy transmissions.Second, three ADHDP-based neural networks, which can update themselves during applications, are designed to manage the flows of electricity. Third, simulation results show that the proposed scheduling method has effectively reduced the total electricity cost and improved load balancing process. The comparison with the particle swarm optimization algorithm further proves that the present method has a promising effect on energy management to save cost.展开更多
The time dependent vehicle routing problem with time windows（TDVRPTW） is considered. A multi-type ant system（MTAS） algorithm hybridized with the ant colony system（ACS）and the max-min ant system（MMAS） algorithm...The time dependent vehicle routing problem with time windows（TDVRPTW） is considered. A multi-type ant system（MTAS） algorithm hybridized with the ant colony system（ACS）and the max-min ant system（MMAS） algorithms is proposed. This combination absorbs the merits of the two algorithms in solutions construction and optimization separately. In order to improve the efficiency of the insertion procedure, a nearest neighbor selection（NNS） mechanism, an insertion local search procedure and a local optimization procedure are specified in detail. And in order to find a balance between good scouting performance and fast convergence rate, an adaptive pheromone updating strategy is proposed in the MTAS. Computational results confirm the MTAS algorithm＇s good performance with all these strategies on classic vehicle routing problem with time windows（VRPTW） benchmark instances and the TDVRPTW instances, and some better results especially for the number of vehicles and travel times of the best solutions are obtained in comparison with the previous research.展开更多
Classical interferon-alpha has been shown to be correlated with the development of a variety of autoimmune disorders. A 38 year-old female patient developed simultaneously diabetic ketoacidosis and hyperthyroidism 5 m...Classical interferon-alpha has been shown to be correlated with the development of a variety of autoimmune disorders. A 38 year-old female patient developed simultaneously diabetic ketoacidosis and hyperthyroidism 5 mo following initiation of treatment with pegylated interferon-α and ribavirin for chronic hepatitis C. High titers of glutamic acid decarboxylase, antinuclear and thyroid (thyroid peroxidase and thyroglobulin) antibodies were detected. Antiviral treatment was withdrawn and the patient was treated with insulin for insulin-dependent diabetes mellitus and propranolol for hyperthyroidism. Twelve months after cessation of pegylated interferon-α therapy the patient was euthyroid without any medication but remained insulin-dependent.展开更多
Patch clamp techniques were employed to investigate if calcium dependent protein kinases (CDPKs) be involved in the signal transduction pathways of stomatal movement regulation by the phytohormone abscisic acid (ABA...Patch clamp techniques were employed to investigate if calcium dependent protein kinases (CDPKs) be involved in the signal transduction pathways of stomatal movement regulation by the phytohormone abscisic acid (ABA) in Vicia faba. Stomatal opening was completely inhibited by external application of 1 μmol/L ABA, and such ABA inhibition was significantly reversed by the addition of CDPK inhibitor trifluoperazine (TFP). The inward whole cell K + currents were inhibited by 60% in the presence of 1 μmol/L intracellular ABA, and this inhibition was completely abolished by the addition of CDPK competitive substrate histone Ⅲ S. The results suggest that CDPKs may be involved in the signal transduction cascades of ABA regulated stomatal movements.展开更多
The SEIR epidemic model studied here includes constant inflows of new susceptibles, exposeds, infectives, and recovereds. This model also incorporates a population size dependent contact rate and a disease-related dea...The SEIR epidemic model studied here includes constant inflows of new susceptibles, exposeds, infectives, and recovereds. This model also incorporates a population size dependent contact rate and a disease-related death. As the infected fraction cannot be eliminated from the population, this kind of model has only the unique endemic equilibrium that is globally asymptotically stable. Under the special case where the new members of immigration are all susceptible, the model considered here shows a threshold phenomenon and a sharp threshold has been obtained. In order to prove the global asymptotical stability of the endemic equilibrium, the authors introduce the change of variable, which can reduce our four-dimensional system to a three-dimensional asymptotical autonomous system with limit equation.展开更多
Explaining the "Tragedy of the Commons" of the evolution of cooperation remains one of the greatest problems for both biology and social science.Asymmetrical interaction,which is one of the most important ch...Explaining the "Tragedy of the Commons" of the evolution of cooperation remains one of the greatest problems for both biology and social science.Asymmetrical interaction,which is one of the most important characteristics of cooperative systems,has not been sufficiently considered in the existing models of the evolution of cooperation.Considering the inequality in the number and payoff between the cooperative actors and recipients in cooperation systems,discriminative density-dependent interference competition will occur in limited dispersal systems.Our model and simulation show that the local but not the global stability of a cooperative interaction can be maintained if the utilization of common resource remains unsaturated,which can be achieved by density-dependent restraint or competition among the cooperative actors.More intense density dependent interference competition among the cooperative actors and the ready availability of the common resource,with a higher intrinsic contribution ratio of a cooperative actor to the recipient,will increase the probability of cooperation.The cooperation between the recipient and the cooperative actors can be transformed into conflict and,it oscillates chaotically with variations of the affecting factors under different environmental or ecological conditions.The higher initial relatedness(i.e.similar to kin or reciprocity relatedness),which is equivalent to intrinsic contribution ratio of a cooperative actor to the recipient,can be selected for by penalizing less cooperative or cheating actors but rewarding cooperative individuals in asymmetric systems.The initial relatedness is a pivot but not the aim of evolution of cooperation.This explains well the direct conflict observed in almost all cooperative systems.展开更多
Assessment of time dependent seismic hazards on segments of active fault is one of the important techniques of long term earthquake forecast for specific locations. It is based on the data from quantitatively seismo g...Assessment of time dependent seismic hazards on segments of active fault is one of the important techniques of long term earthquake forecast for specific locations. It is based on the data from quantitatively seismo geologic investigation in active faults and expresses seismic hazards of a fault segment with both the earthquake occurrence probability, which increases as the elapsed time increases, and the magnitude predicted. Through summing up and analyzing main technical steps in research of the recent decade, some defects in the current theory and model of this technique are pointed out. For instance, the probabilistic models for recurrence interval are based solely on the quasi periodic behavior of earthquake recurrence, ignoring behavior’s diversity that possibly exists. Variability of repeated rupture dimensions in various cycles is considered inadequately in fault segmentation research, etc. It is most important for improving the reliability of the result of seismic hazard assessment to reveal actual earthquake recurrence behavior and its generalities, and to update relevant models for evaluating probabilistic earthquake hazard based on the behavior and generalities.展开更多
The hybrid-HVDC topology,which consists of line-commutated-converter(LCC)and voltage source converter(VSC)and combines their advantages,has extensive application prospects.A hybrid-HVDC system,adopting VSC on rectifie...The hybrid-HVDC topology,which consists of line-commutated-converter(LCC)and voltage source converter(VSC)and combines their advantages,has extensive application prospects.A hybrid-HVDC system,adopting VSC on rectifier side and LCC on inverter side,is investigated,and its mathematic model is deduced.The commutation failure issue of the LCC converter in the hybrid-HVDC system is considered,and a novel coordinated control method is proposed to enhance the system commutation failure immunity.A voltage dependent voltage order limiter(VDVOL)is designed based on the constant DC voltage control on the rectifier side,and constant extinction angle backup control is introduced based on the constant DC current control with voltage dependent current order limiter(VDCOL)on the inverter side.The hybrid-HVDC system performances under normal operation state and fault state are simulated in the PSCAD/EMTDC.Then,system transient state performances with or without the proposed control methods under fault condition are further compared and analyzed.It is concluded that the proposed control method has the ability to effectively reduce the probability of commutation failure and improve the fault recovery performance of the hybrid-HVDC system.展开更多
In the past ten years, many high-quality datasets have been released to support the rapid development of deep learning in the fields of computer vision, voice, and natural language processing. Nowadays, deep learning ...In the past ten years, many high-quality datasets have been released to support the rapid development of deep learning in the fields of computer vision, voice, and natural language processing. Nowadays, deep learning has become a key research component of the Sixth-Generation wireless systems(6G) with numerous regulatory and defense applications. In order to facilitate the application of deep learning in radio signal recognition, in this work, a large-scale real-world radio signal dataset is created based on a special aeronautical monitoring system-Automatic Dependent Surveillance-Broadcast(ADS-B). This paper makes two main contributions. First, an automatic data collection and labeling system is designed to capture over-the-air ADS-B signals in the open and real-world scenario without human participation. Through data cleaning and sorting, a high-quality dataset of ADS-B signals is created for radio signal recognition. Second, we conduct an in-depth study on the performance of deep learning models using the new dataset, as well as comparison with a recognition benchmark using machine learning and deep learning methods.Finally, we conclude this paper with a discussion of open problems in this area.展开更多
基金Supported by National Natural Science Foundation of China(Grant No.11271161)
文摘In this paper, we establish a complete convergence result and a complete moment convergence result for weighted sums of widely orthant dependent random variables under mild conditions. As corollaries, the corresponding results for weighted sums of extended negatively orthant dependent random variables are also obtained, which generalize and improve the related known works in the literature.
文摘Objective To investigate the expressions of cyclin E, cyclin dependent kinase 2(CDK-2)and cyclin-dependent kinase inhibitor p57 KIP2 in human gastric cancer, and to evaluate the relationships between protein levels and clinicopathological parameters. Methods Western blot was used to measure the expressions of cyclin E, CDK-2 and p57 KIP2 proteins in the surgically resected gastric carcinoma, adjacent normal mucosa and metastatic lymph nodes from 36 patients. Results Cyclin E and CDK-2 protein levels were higher in gastric cancer tissues in comparison with normal tissues (P<0.05). Overexpression of cyclin E was correlated with lymph node involvement, poor histological grade and serosa invasion (P<0.05). Overexpression of CDK-2 was correlated with lymph nodes involvement (P<0.05). No statistically significant difference between cyclin E and CDK-2 expression was found when samples were stratified according to tumor size (P>0.05). Expression of cyclin E and CDK-2 showed a positive linear correlation (r=0.451, P=0.01). Protein levels of p57 KIP2 were lower in gastric cancer tissues than in the normal mucosa (P<0.05). Decreased expression of p57 KIP2 was correlated with lymph node involvement (P<0.05). No statistically significant difference in p57 KIP2 expression was found when sample were stratified according to tumor size, histological grade or serosa invasion (P>0.05). In metastatic lymph nodes, expression of cyclin E was increased and the expression of p57 KIP2 decreased. Conclusion Overexpressions of cyclin E, CDK-2 and downregulated expression of p57 KIP2 may play important roles in tumorigenesis and metastatic potential of gastric cancer.
文摘In any multi-cellular organism, the balance between cell division and cell death maintains a constant cell number. Both cell division cycle and cell death are highly regulated events. Whether the cell will proceed through the cycle or not, depends upon whether the conditions required at the checkpoints during the cycle are fulfilled. In higher eucaryotic cells, such as mammalian cells, signals that arrest the cycle usually act at a G1 checkpoint. Cells that pass this restriction point are committed to complete the cycle. Regulation of the GI phase of the cell cycle is extremely complex and involves many different families of proteins such as retinoblastoma family cyclin dependent kinases, cyclins, and cyclic kinase inhibitors.
文摘目的研究体外人骨髓间充质干细胞(MSCs)和汗腺细胞(SGCs)直接和间接共培养条件下骨髓间充质干细胞的表型转化及其机制。方法体外分别分离培养、扩增并鉴定MSCs和汗腺细胞。将培养的MSCs和经47℃高温处理造成热休克的SGCs直接和间接共培养,1周后,采用免疫细胞化学染色法和流式细胞仪法检测共培养体系中MSCs的表型改变,W estern b lot测定细胞外信号调节激酶(ERK)和磷酸化细胞外信号调节激酶(pERK)表达。结果MSCs和SGCs均呈克隆样生长,MSCs表达CD44、CD105和CD29,不表达CD34、CEA、CK19和CK7;SGCs表达CEA、CK19、CK8和CK7。MSCs与经高温损伤后的SGCs共培养1周后,部分MSCs呈汗腺细胞表型,间接共培养结果示各组MSCs均表达水平相当的ERK,但pERK水平表达不同。结论成人MSCs和热休克的SGCs直接和间接共培养均可诱导MSCs向SGCs表型转化,pERK途径参与这一过程。
文摘For the widely orthant dependent （WOD） structure, this paper mainly investigates the precise large deviations for the partial sums of WOD and non-identically distributed random variables with dominatedly varying tails. The obtained results extend some corresponding results.
文摘AIM: To examine the role of p38 during acute experimental cerulein pancreatitis. METHODS: Rats were treated with cerulein with or without a specific JNK inhibitor (CEP1347) and/or a specific p38 inhibitor (SB203580) and pancreatic stress kinase activity was determined. Parameters to assess pancreatitis included trypsin, amylase, lipase, pancreatic weight and histology. RESULTS: JNK inhibition with CEP1347 ameliorated pancreatitis, reducing pancreatic edema. In contrast, p38 inhibition with SB203580 aggravated pancreatitis with higher trypsin levels and, with induction of acinar necrosis not normally found after cerulein hyperstimulation. Simultaneous treatment with both CEP1347 and SB203580 mutually abolished the effects of either compound on cerulein pancreatitis. CONCLUSION: Stress kinases modulate pancreatitis differentially. JNK seems to promote pancreatitis development, possibly by supporting inflammatory reactions such as edema formation while its inhibition ameliorates pancreatitis. In contrast, p38 may help reduce organ destruction while inhibition of p38 during induction of cerulein pancreatitis leads to the occurrence of acinar necrosis.
基金Supported by National Natural Science Foundation of China(Grant Nos.11171001,11201001 and 11126176)Natural Science Foundation of Anhui Province(1208085QA03)Academic Innovation Team of Anhui University(Grant No.KJTD001B)
文摘In this paper, Kolmogorov-type inequality for negatively superadditive dependent （NSD） random variables is established. By using this inequality, we obtain the almost sure convergence for NSD sequences, which extends the corresponding results for independent sequences and negatively associated （NA） sequences. In addition, the strong stability for weighted sums of NSD random variables is studied.
基金supported in part by the National Natural Science Foundation of China(61533017,U1501251,61374105,61722312)
文摘The residential energy scheduling of solar energy is an important research area of smart grid. On the demand side, factors such as household loads, storage batteries, the outside public utility grid and renewable energy resources, are combined together as a nonlinear, time-varying, indefinite and complex system, which is difficult to manage or optimize. Many nations have already applied the residential real-time pricing to balance the burden on their grid. In order to enhance electricity efficiency of the residential micro grid, this paper presents an action dependent heuristic dynamic programming(ADHDP) method to solve the residential energy scheduling problem. The highlights of this paper are listed below. First,the weather-type classification is adopted to establish three types of programming models based on the features of the solar energy. In addition, the priorities of different energy resources are set to reduce the loss of electrical energy transmissions.Second, three ADHDP-based neural networks, which can update themselves during applications, are designed to manage the flows of electricity. Third, simulation results show that the proposed scheduling method has effectively reduced the total electricity cost and improved load balancing process. The comparison with the particle swarm optimization algorithm further proves that the present method has a promising effect on energy management to save cost.
文摘The time dependent vehicle routing problem with time windows（TDVRPTW） is considered. A multi-type ant system（MTAS） algorithm hybridized with the ant colony system（ACS）and the max-min ant system（MMAS） algorithms is proposed. This combination absorbs the merits of the two algorithms in solutions construction and optimization separately. In order to improve the efficiency of the insertion procedure, a nearest neighbor selection（NNS） mechanism, an insertion local search procedure and a local optimization procedure are specified in detail. And in order to find a balance between good scouting performance and fast convergence rate, an adaptive pheromone updating strategy is proposed in the MTAS. Computational results confirm the MTAS algorithm＇s good performance with all these strategies on classic vehicle routing problem with time windows（VRPTW） benchmark instances and the TDVRPTW instances, and some better results especially for the number of vehicles and travel times of the best solutions are obtained in comparison with the previous research.
文摘Classical interferon-alpha has been shown to be correlated with the development of a variety of autoimmune disorders. A 38 year-old female patient developed simultaneously diabetic ketoacidosis and hyperthyroidism 5 mo following initiation of treatment with pegylated interferon-α and ribavirin for chronic hepatitis C. High titers of glutamic acid decarboxylase, antinuclear and thyroid (thyroid peroxidase and thyroglobulin) antibodies were detected. Antiviral treatment was withdrawn and the patient was treated with insulin for insulin-dependent diabetes mellitus and propranolol for hyperthyroidism. Twelve months after cessation of pegylated interferon-α therapy the patient was euthyroid without any medication but remained insulin-dependent.
文摘Patch clamp techniques were employed to investigate if calcium dependent protein kinases (CDPKs) be involved in the signal transduction pathways of stomatal movement regulation by the phytohormone abscisic acid (ABA) in Vicia faba. Stomatal opening was completely inhibited by external application of 1 μmol/L ABA, and such ABA inhibition was significantly reversed by the addition of CDPK inhibitor trifluoperazine (TFP). The inward whole cell K + currents were inhibited by 60% in the presence of 1 μmol/L intracellular ABA, and this inhibition was completely abolished by the addition of CDPK competitive substrate histone Ⅲ S. The results suggest that CDPKs may be involved in the signal transduction cascades of ABA regulated stomatal movements.
基金This research is supported by the NNSF of China (19971066)
文摘The SEIR epidemic model studied here includes constant inflows of new susceptibles, exposeds, infectives, and recovereds. This model also incorporates a population size dependent contact rate and a disease-related death. As the infected fraction cannot be eliminated from the population, this kind of model has only the unique endemic equilibrium that is globally asymptotically stable. Under the special case where the new members of immigration are all susceptible, the model considered here shows a threshold phenomenon and a sharp threshold has been obtained. In order to prove the global asymptotical stability of the endemic equilibrium, the authors introduce the change of variable, which can reduce our four-dimensional system to a three-dimensional asymptotical autonomous system with limit equation.
基金supported by the National Basic Research Program of China (Grant No 2007CB411600)the National Natural Science Foundation of China (Grant Nos 30670272, 30770500 and 10761010)+1 种基金the Yunnan Natural Science Foundation (Grant No 2009CD104)the West Light Foundation of the Chinese Academy of Sciences and the National Social Science Foundation of China (Grant No 08XTJ001)
文摘Explaining the "Tragedy of the Commons" of the evolution of cooperation remains one of the greatest problems for both biology and social science.Asymmetrical interaction,which is one of the most important characteristics of cooperative systems,has not been sufficiently considered in the existing models of the evolution of cooperation.Considering the inequality in the number and payoff between the cooperative actors and recipients in cooperation systems,discriminative density-dependent interference competition will occur in limited dispersal systems.Our model and simulation show that the local but not the global stability of a cooperative interaction can be maintained if the utilization of common resource remains unsaturated,which can be achieved by density-dependent restraint or competition among the cooperative actors.More intense density dependent interference competition among the cooperative actors and the ready availability of the common resource,with a higher intrinsic contribution ratio of a cooperative actor to the recipient,will increase the probability of cooperation.The cooperation between the recipient and the cooperative actors can be transformed into conflict and,it oscillates chaotically with variations of the affecting factors under different environmental or ecological conditions.The higher initial relatedness(i.e.similar to kin or reciprocity relatedness),which is equivalent to intrinsic contribution ratio of a cooperative actor to the recipient,can be selected for by penalizing less cooperative or cheating actors but rewarding cooperative individuals in asymmetric systems.The initial relatedness is a pivot but not the aim of evolution of cooperation.This explains well the direct conflict observed in almost all cooperative systems.
文摘Assessment of time dependent seismic hazards on segments of active fault is one of the important techniques of long term earthquake forecast for specific locations. It is based on the data from quantitatively seismo geologic investigation in active faults and expresses seismic hazards of a fault segment with both the earthquake occurrence probability, which increases as the elapsed time increases, and the magnitude predicted. Through summing up and analyzing main technical steps in research of the recent decade, some defects in the current theory and model of this technique are pointed out. For instance, the probabilistic models for recurrence interval are based solely on the quasi periodic behavior of earthquake recurrence, ignoring behavior’s diversity that possibly exists. Variability of repeated rupture dimensions in various cycles is considered inadequately in fault segmentation research, etc. It is most important for improving the reliability of the result of seismic hazard assessment to reveal actual earthquake recurrence behavior and its generalities, and to update relevant models for evaluating probabilistic earthquake hazard based on the behavior and generalities.
基金supported by the National High Technology Research and Development Program of China("863" Program)(Grant No.2013AA050105)the National Natural Science Foundation of China(Grant No.51177042)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.13QN03)2012 science and technology projects of State Grid Corporation of China(Grant No.XT71-12-015)
文摘The hybrid-HVDC topology,which consists of line-commutated-converter(LCC)and voltage source converter(VSC)and combines their advantages,has extensive application prospects.A hybrid-HVDC system,adopting VSC on rectifier side and LCC on inverter side,is investigated,and its mathematic model is deduced.The commutation failure issue of the LCC converter in the hybrid-HVDC system is considered,and a novel coordinated control method is proposed to enhance the system commutation failure immunity.A voltage dependent voltage order limiter(VDVOL)is designed based on the constant DC voltage control on the rectifier side,and constant extinction angle backup control is introduced based on the constant DC current control with voltage dependent current order limiter(VDCOL)on the inverter side.The hybrid-HVDC system performances under normal operation state and fault state are simulated in the PSCAD/EMTDC.Then,system transient state performances with or without the proposed control methods under fault condition are further compared and analyzed.It is concluded that the proposed control method has the ability to effectively reduce the probability of commutation failure and improve the fault recovery performance of the hybrid-HVDC system.
基金supported by the National Natural Science Foundation of China(No.61771154)the Fundamental Research Funds for the Central Universities,China(No.3072021CF0815)supported by the Key Laboratory of Advanced Marine Communication and Information Technology,Ministry of Industry and Information Technology,Harbin Engineering University,Harbin,China。
文摘In the past ten years, many high-quality datasets have been released to support the rapid development of deep learning in the fields of computer vision, voice, and natural language processing. Nowadays, deep learning has become a key research component of the Sixth-Generation wireless systems(6G) with numerous regulatory and defense applications. In order to facilitate the application of deep learning in radio signal recognition, in this work, a large-scale real-world radio signal dataset is created based on a special aeronautical monitoring system-Automatic Dependent Surveillance-Broadcast(ADS-B). This paper makes two main contributions. First, an automatic data collection and labeling system is designed to capture over-the-air ADS-B signals in the open and real-world scenario without human participation. Through data cleaning and sorting, a high-quality dataset of ADS-B signals is created for radio signal recognition. Second, we conduct an in-depth study on the performance of deep learning models using the new dataset, as well as comparison with a recognition benchmark using machine learning and deep learning methods.Finally, we conclude this paper with a discussion of open problems in this area.
