Data from the World Federation of Exchanges show that Brazil＇s Sao Paulo stock exchange is one of the largest worldwide in terms of market value. Thus, the objective of this study is to obtain univariate and bivariat...Data from the World Federation of Exchanges show that Brazil＇s Sao Paulo stock exchange is one of the largest worldwide in terms of market value. Thus, the objective of this study is to obtain univariate and bivariate forecasting models based on intraday data from the futures and spot markets of the BOVESPA index. The interest is to verify if there exist arbitrage opportunities in Brazilian financial market. To this end, three econometric forecasting models were built： ARFIMA, vector autoregressive （VAR）, and vector error correction （VEC）. Furthermore, it presents the results of a Granger causality test for the aforementioned series. This type of study shows that it is important to identify arbitrage opportunities in financial markets and, in particular, in the application of these models on data of this nature. In terms of the forecasts made with these models, VEC showed better results. The causality test shows that futures BOVESPA index Granger causes spot BOVESPA index. This result may indicate arbitrage opportunities in Brazil.展开更多
Logistics is an important part of the supply chain and connect all aspects of the supply chain throughout it, which has become business cooperation ties. In the process of developing supply chain logistics strategy, g...Logistics is an important part of the supply chain and connect all aspects of the supply chain throughout it, which has become business cooperation ties. In the process of developing supply chain logistics strategy, generally require attention to the following questions： To segment customers, we should determine the appropriate level of customer service, such as order cycle, inventory levels and other modes of transport for different types of clients; Group products according to sales on them, we can take different strategies for each category of products. Order entry, order execution and delivery job processing accounted for a large proportion of logistics activities, which requires technology and management to make the entire processes of supply chain logistics more efficient, especially for the interface area between members of enterprises. We can eliminate redundant work by integrating flow, improve logistics efficiency.展开更多
Power systems in Germany mainly containing intermittently operating renewable sources require load/frequency control which is performed up to now at the AC transmissioh and distribution levels. Frequency control can b...Power systems in Germany mainly containing intermittently operating renewable sources require load/frequency control which is performed up to now at the AC transmissioh and distribution levels. Frequency control can be achieved by employing short-and long-term storage plants buffering and complementing renewable energy sources. A representative grid consists of a natural-gas-fired plant serving as frequency leader, long-term storage plant, wind-power farm with associated short-term storage plantfor energy buffering, and photovoltaic farm with associated short-term storage plant interconnected by a long transmission line to two load circuits. Transient analysis is performed with Mathemafica solving the differential equation system for frequency variation. Powerflow through the AC transmission line is limited by its impedance. The long transmission line must be segmented to achieve stability and voltage control over an 800 km distance. The renewable plants must be operated together with the storage plants in order tominimize frequency variations by smoothing the power output of renewable plants, achieving step-wise control of the transmission-line power. Although to date only AC Iransmission lines in Germany exist, it is anticipated that within the next 10 years these will beaugmented by DC high-voltage lines.展开更多
The reverse construction and analysis of the networks of molecular interactions are essential for understanding their functions within cells. In this paper, a logic network model is constructed to investigate the comp...The reverse construction and analysis of the networks of molecular interactions are essential for understanding their functions within cells. In this paper, a logic network model is constructed to investigate the complicated regulation mechanism of shoot genes of Arabidopsis Thaliana in response to stimuli. The dynamics of the complicated logic network is analyzed, discussed, and simulated. The simulation results show that the logic network of the active genes of shoot eventually evolves into eleven attractors under the stimuli, including five 1-periodic and six 2-periodic attractors. Our work provides valuable reference and guidance for biologists to understand and explain Arabidopsis＇ response to external stimuli by experiments.展开更多
文摘Data from the World Federation of Exchanges show that Brazil＇s Sao Paulo stock exchange is one of the largest worldwide in terms of market value. Thus, the objective of this study is to obtain univariate and bivariate forecasting models based on intraday data from the futures and spot markets of the BOVESPA index. The interest is to verify if there exist arbitrage opportunities in Brazilian financial market. To this end, three econometric forecasting models were built： ARFIMA, vector autoregressive （VAR）, and vector error correction （VEC）. Furthermore, it presents the results of a Granger causality test for the aforementioned series. This type of study shows that it is important to identify arbitrage opportunities in financial markets and, in particular, in the application of these models on data of this nature. In terms of the forecasts made with these models, VEC showed better results. The causality test shows that futures BOVESPA index Granger causes spot BOVESPA index. This result may indicate arbitrage opportunities in Brazil.
文摘Logistics is an important part of the supply chain and connect all aspects of the supply chain throughout it, which has become business cooperation ties. In the process of developing supply chain logistics strategy, generally require attention to the following questions： To segment customers, we should determine the appropriate level of customer service, such as order cycle, inventory levels and other modes of transport for different types of clients; Group products according to sales on them, we can take different strategies for each category of products. Order entry, order execution and delivery job processing accounted for a large proportion of logistics activities, which requires technology and management to make the entire processes of supply chain logistics more efficient, especially for the interface area between members of enterprises. We can eliminate redundant work by integrating flow, improve logistics efficiency.
文摘Power systems in Germany mainly containing intermittently operating renewable sources require load/frequency control which is performed up to now at the AC transmissioh and distribution levels. Frequency control can be achieved by employing short-and long-term storage plants buffering and complementing renewable energy sources. A representative grid consists of a natural-gas-fired plant serving as frequency leader, long-term storage plant, wind-power farm with associated short-term storage plantfor energy buffering, and photovoltaic farm with associated short-term storage plant interconnected by a long transmission line to two load circuits. Transient analysis is performed with Mathemafica solving the differential equation system for frequency variation. Powerflow through the AC transmission line is limited by its impedance. The long transmission line must be segmented to achieve stability and voltage control over an 800 km distance. The renewable plants must be operated together with the storage plants in order tominimize frequency variations by smoothing the power output of renewable plants, achieving step-wise control of the transmission-line power. Although to date only AC Iransmission lines in Germany exist, it is anticipated that within the next 10 years these will beaugmented by DC high-voltage lines.
基金This research is supported by the National Natural Science Foundation of China under Grant Nos. 60874036 and 60503002.
文摘The reverse construction and analysis of the networks of molecular interactions are essential for understanding their functions within cells. In this paper, a logic network model is constructed to investigate the complicated regulation mechanism of shoot genes of Arabidopsis Thaliana in response to stimuli. The dynamics of the complicated logic network is analyzed, discussed, and simulated. The simulation results show that the logic network of the active genes of shoot eventually evolves into eleven attractors under the stimuli, including five 1-periodic and six 2-periodic attractors. Our work provides valuable reference and guidance for biologists to understand and explain Arabidopsis＇ response to external stimuli by experiments.
