Top-k ranking of websites according to traffic volume is important for Internet Service Providers(ISPs) to understand network status and optimize network resources. However, the ranking result always has a big deviati...Top-k ranking of websites according to traffic volume is important for Internet Service Providers(ISPs) to understand network status and optimize network resources. However, the ranking result always has a big deviation with actual rank for the existence of unknown web traffic, which cannot be identified accurately under current techniques. In this paper, we introduce a novel method to approximate the actual rank. This method associates unknown web traffic with websites according to statistical probabilities. Then, we construct a probabilistic top-k query model to rank websites. We conduct several experiments by using real HTTP traffic traces collected from a commercial ISP covering an entire city in northern China. Experimental results show that the proposed techniques can reduce the deviation existing between the ground truth and the ranking results vastly. In addition, we find that the websites providing video service have higher ratio of unknown IP as well as higher ratio of unknown traffic than the websites providing text web page service. Specifically, we find that the top-3 video websites have more than 90% of unknown web traffic. All these findings are helpful for ISPs understanding network status and deploying Content Distributed Network(CDN).展开更多
The existing literature on innovation concentrates mostly on large industrial firms and high-technology industries, whereas, little attention has been given to agribusiness. Empirical evidence regarding the driving fo...The existing literature on innovation concentrates mostly on large industrial firms and high-technology industries, whereas, little attention has been given to agribusiness. Empirical evidence regarding the driving forces behind innovation in agribusinesses in developing countries, China in particular is scarce. This paper helps fill that void. It develops a framework in which innovation results from synergies between internal resources and external networks. This paper applies and tests the framework using 2003-2005 data from a panel survey of 32 leading agribusiness firms in Shandong Province, China. The empirical results indicate the importance of internal resources, external networks and the synergies between them. We find that R＆D expenditures and the number of technical employees are internal resources that are both important to product innovation. Surprisingly, management quality is negatively related to the possession of a unique technology and new products as a proportion of all products. It is possible that management quality is associated with more formalization and rigidity in decision-making, hindering creativity and lengthening the new product development cycle. In order to develop innovative products, our results suggest that investing in R＆D and hiring more technical staff may be more effective approaches than spending on managerial talent.展开更多
An important problem in demand planning for energy consumption is developing an accurate energy forecasting model. In fact, it is not possible to allocate the energy resources in an optimal manner without having accur...An important problem in demand planning for energy consumption is developing an accurate energy forecasting model. In fact, it is not possible to allocate the energy resources in an optimal manner without having accurate demand value. A new energy forecasting model was proposed based on the back-propagation(BP) type neural network and imperialist competitive algorithm. The proposed method offers the advantage of local search ability of BP technique and global search ability of imperialist competitive algorithm. Two types of empirical data regarding the energy demand(gross domestic product(GDP), population, import, export and energy demand) in Turkey from 1979 to 2005 and electricity demand(population, GDP, total revenue from exporting industrial products and electricity consumption) in Thailand from 1986 to 2010 were investigated to demonstrate the applicability and merits of the present method. The performance of the proposed model is found to be better than that of conventional back-propagation neural network with low mean absolute error.展开更多
基金supported by 111 Project of China under Grant No.B08004
文摘Top-k ranking of websites according to traffic volume is important for Internet Service Providers(ISPs) to understand network status and optimize network resources. However, the ranking result always has a big deviation with actual rank for the existence of unknown web traffic, which cannot be identified accurately under current techniques. In this paper, we introduce a novel method to approximate the actual rank. This method associates unknown web traffic with websites according to statistical probabilities. Then, we construct a probabilistic top-k query model to rank websites. We conduct several experiments by using real HTTP traffic traces collected from a commercial ISP covering an entire city in northern China. Experimental results show that the proposed techniques can reduce the deviation existing between the ground truth and the ranking results vastly. In addition, we find that the websites providing video service have higher ratio of unknown IP as well as higher ratio of unknown traffic than the websites providing text web page service. Specifically, we find that the top-3 video websites have more than 90% of unknown web traffic. All these findings are helpful for ISPs understanding network status and deploying Content Distributed Network(CDN).
文摘The existing literature on innovation concentrates mostly on large industrial firms and high-technology industries, whereas, little attention has been given to agribusiness. Empirical evidence regarding the driving forces behind innovation in agribusinesses in developing countries, China in particular is scarce. This paper helps fill that void. It develops a framework in which innovation results from synergies between internal resources and external networks. This paper applies and tests the framework using 2003-2005 data from a panel survey of 32 leading agribusiness firms in Shandong Province, China. The empirical results indicate the importance of internal resources, external networks and the synergies between them. We find that R＆D expenditures and the number of technical employees are internal resources that are both important to product innovation. Surprisingly, management quality is negatively related to the possession of a unique technology and new products as a proportion of all products. It is possible that management quality is associated with more formalization and rigidity in decision-making, hindering creativity and lengthening the new product development cycle. In order to develop innovative products, our results suggest that investing in R＆D and hiring more technical staff may be more effective approaches than spending on managerial talent.
文摘An important problem in demand planning for energy consumption is developing an accurate energy forecasting model. In fact, it is not possible to allocate the energy resources in an optimal manner without having accurate demand value. A new energy forecasting model was proposed based on the back-propagation(BP) type neural network and imperialist competitive algorithm. The proposed method offers the advantage of local search ability of BP technique and global search ability of imperialist competitive algorithm. Two types of empirical data regarding the energy demand(gross domestic product(GDP), population, import, export and energy demand) in Turkey from 1979 to 2005 and electricity demand(population, GDP, total revenue from exporting industrial products and electricity consumption) in Thailand from 1986 to 2010 were investigated to demonstrate the applicability and merits of the present method. The performance of the proposed model is found to be better than that of conventional back-propagation neural network with low mean absolute error.
