Most of data distribution mechanism in Opportunistic Networks is derived by Epidemic data distribution,and Epidemic data distribution means that when each node meets another node,it may copy its own messages and trans...Most of data distribution mechanism in Opportunistic Networks is derived by Epidemic data distribution,and Epidemic data distribution means that when each node meets another node,it may copy its own messages and transfer to another node.On the one hand,the copies improve the forwarding rate,and reduce the transmission delay.However,on the other hand,energy consumption increases and network survival time is reduced because the copies consume transmission resource.Therefore,copy number should be under control.In this paper,we first introduce the existing routing strategy based on Epidemic briefly,and present the Epidemic routing protocol analysis model and copy control mechanism based on the limited Epidemic in Opportunistic Networks.Then based on the limited copies scheme(LCS),we propose an energy balance scheme(EBS),the results show that EBS can improve the network survival time.展开更多
Traffic congestion has caused many detrimental effects including higher fuel consumption, more vehicle emissions, increased accidents, as well as greater tension due to uncertain travel time. In addition to delay, the...Traffic congestion has caused many detrimental effects including higher fuel consumption, more vehicle emissions, increased accidents, as well as greater tension due to uncertain travel time. In addition to delay, the variability and reliability of travel time has been of concern to motorists on their daily travel, especially during peak periods. The objective of this study is to examine freeway travel time variability and reliability under different traffic and weather conditions with the use of TRANSMIT data collected by roadside readers deployed on a 40-mile segment of the Interstate Highway 1-287 in New Jersey. Travel time variability and reliability measures including mean travel time, the 95th percentile travel time, travel time index, buffer index, and planning time index under recurring and non-recurring congestion （adverse weather） are investigated. It was found that the standard deviation of travel time increased, due to the weather condition varying from dry to rain and to snow, while the buffer index increased from 29% to 45% and to 94%.展开更多
This paper describes two methods of representation of voltages and currents in electric circuits： in the vector form and in the shape of oscillations, represented as diagrams in the plane. The appropriate power compo...This paper describes two methods of representation of voltages and currents in electric circuits： in the vector form and in the shape of oscillations, represented as diagrams in the plane. The appropriate power components are discussed depending on the representation of voltages and currents. Special attention is paid to the instantaneous power peculiarities for diverse loads and non-sinusoidal conditions. A case study of power calculations in an electric circuit with a pluggable capacitor is presented. For these types of transient modes, the instantaneous power is represented in the form of active and reactive components. Calculation of active, reactive, and exchange powers for steady-state processes is presented.展开更多
Objective： To analyze the time factor in road traffic accidents （RTAs） in Fats Province of Iran. Methods： This study was conducted in Fars Province, Iran from November 22, 2009 to November 21,2011. Victims＇ info...Objective： To analyze the time factor in road traffic accidents （RTAs） in Fats Province of Iran. Methods： This study was conducted in Fars Province, Iran from November 22, 2009 to November 21,2011. Victims＇ information consisted of age, sex, death toll involving dri- vers or passengers of cars, motorcycles and pedestrians, and site of injury etc. Accidents were analyzed in relation to hour of the day, season of the year, lighting condition in- cluding sunrise, sunset, daytime and nighttime. Results： Atotal of 3 642 deaths （78.3% were males, and the ratio of males to females was about 3.6：1） were studied regarding their autopsy records. There was a steady in- crease in fatal accidents occurring at midnight to 15：59. The risk of being involved in a fatal traffic accident was higherfor those injured between 4：00 to 7：59 than at other times （OR=2.13, 95% C11.85-2.44）. The greatest number of fatal RTAs took place in summer. Mortalities due to RTA during spring and summer were more pronounced at 20：00 to 23：59 and midnight to 3：59, whereas mortalities in fall and winter were more pronounced from 12：00 to 15：59. Conclusion： The high mortality rate ofRTAis a major public health problem in Fars Province. Our results indicate that the time is an important factor which contributes to road traffic deaths.展开更多
基金supported by the National Natural Science Foundation of China(61171097)Key Lab of Information Network Security, Ministry of Public Security(C14613)
文摘Most of data distribution mechanism in Opportunistic Networks is derived by Epidemic data distribution,and Epidemic data distribution means that when each node meets another node,it may copy its own messages and transfer to another node.On the one hand,the copies improve the forwarding rate,and reduce the transmission delay.However,on the other hand,energy consumption increases and network survival time is reduced because the copies consume transmission resource.Therefore,copy number should be under control.In this paper,we first introduce the existing routing strategy based on Epidemic briefly,and present the Epidemic routing protocol analysis model and copy control mechanism based on the limited Epidemic in Opportunistic Networks.Then based on the limited copies scheme(LCS),we propose an energy balance scheme(EBS),the results show that EBS can improve the network survival time.
文摘Traffic congestion has caused many detrimental effects including higher fuel consumption, more vehicle emissions, increased accidents, as well as greater tension due to uncertain travel time. In addition to delay, the variability and reliability of travel time has been of concern to motorists on their daily travel, especially during peak periods. The objective of this study is to examine freeway travel time variability and reliability under different traffic and weather conditions with the use of TRANSMIT data collected by roadside readers deployed on a 40-mile segment of the Interstate Highway 1-287 in New Jersey. Travel time variability and reliability measures including mean travel time, the 95th percentile travel time, travel time index, buffer index, and planning time index under recurring and non-recurring congestion （adverse weather） are investigated. It was found that the standard deviation of travel time increased, due to the weather condition varying from dry to rain and to snow, while the buffer index increased from 29% to 45% and to 94%.
文摘This paper describes two methods of representation of voltages and currents in electric circuits： in the vector form and in the shape of oscillations, represented as diagrams in the plane. The appropriate power components are discussed depending on the representation of voltages and currents. Special attention is paid to the instantaneous power peculiarities for diverse loads and non-sinusoidal conditions. A case study of power calculations in an electric circuit with a pluggable capacitor is presented. For these types of transient modes, the instantaneous power is represented in the form of active and reactive components. Calculation of active, reactive, and exchange powers for steady-state processes is presented.
文摘Objective： To analyze the time factor in road traffic accidents （RTAs） in Fats Province of Iran. Methods： This study was conducted in Fars Province, Iran from November 22, 2009 to November 21,2011. Victims＇ information consisted of age, sex, death toll involving dri- vers or passengers of cars, motorcycles and pedestrians, and site of injury etc. Accidents were analyzed in relation to hour of the day, season of the year, lighting condition in- cluding sunrise, sunset, daytime and nighttime. Results： Atotal of 3 642 deaths （78.3% were males, and the ratio of males to females was about 3.6：1） were studied regarding their autopsy records. There was a steady in- crease in fatal accidents occurring at midnight to 15：59. The risk of being involved in a fatal traffic accident was higherfor those injured between 4：00 to 7：59 than at other times （OR=2.13, 95% C11.85-2.44）. The greatest number of fatal RTAs took place in summer. Mortalities due to RTA during spring and summer were more pronounced at 20：00 to 23：59 and midnight to 3：59, whereas mortalities in fall and winter were more pronounced from 12：00 to 15：59. Conclusion： The high mortality rate ofRTAis a major public health problem in Fars Province. Our results indicate that the time is an important factor which contributes to road traffic deaths.
