The deployment of underwater networks allows researchers to collect explorative and monitoring data on underwater ecosystems.The acoustic medium has been widely adopted in current research and commercial uses,while th...The deployment of underwater networks allows researchers to collect explorative and monitoring data on underwater ecosystems.The acoustic medium has been widely adopted in current research and commercial uses,while the optical medium remains experimental only.According to our survey onthe properties of acoustic and optical communicationsand preliminary simulation results have shown significant trade-offs between bandwidth,propagation delay,power consumption,and effective communication range.We propose a hybrid solution that combines the use of acoustic and optical communication in order to overcome the bandwidth limitation of the acoustic channel by enabling optical communicationwith the help of acoustic-assisted alignment between optical transmitters and receivers.展开更多
Nowadays,the number of vehicles in China has increased significantly.The increase of the number of vehicles has also led to the increasingly complex traffic situation and the urgent safety measures in need.However,the...Nowadays,the number of vehicles in China has increased significantly.The increase of the number of vehicles has also led to the increasingly complex traffic situation and the urgent safety measures in need.However,the existing early warning devices such as geomagnetic,ultrasonic and infrared detection have some shortcomings like difficult installation and maintenance.In addition,geomagnetic detection will damage the road surface,while ultrasonic and infrared detection will be greatly affected by the environment.Considering the shortcomings of the existing solutions,this paper puts forward a solution of early warning for vehicle turning meeting based on image acquisition and microcontrollers.This solution combines image acquisition and processing technology,which uses image sensor to perceive traffic condition and image data analysis algorithm to process perceived image,and then utilize LED display screen to issue an early warning.展开更多
We present a network programming mechanism that can flexibly and quickly re-task a large multi-hop network of wireless sensor nodes. Our mechanism allows each sensor node to be incrementally reprogrammed with heteroge...We present a network programming mechanism that can flexibly and quickly re-task a large multi-hop network of wireless sensor nodes. Our mechanism allows each sensor node to be incrementally reprogrammed with heterogeneous images of native program code using Rsync block comparison algorithm, point-to-point routing with the BLIP IPv6 stack, and image volume management with Deluge2. With our re-tasking method, we demonstrate an order of magnitude speed-up on small code changes over non-incremental delivery. Our mechanism also scales sub-linearly in the diameter of the network. Collectively, these advancements qualitatively change the software life cycle of the embedded networked systems.展开更多
The behavior of schools of zebrafish(Danio rerio) was studied in acute toxicity environments.Behavioral features were extracted and a method for water quality assessment using support vector machine(SVM) was de-velope...The behavior of schools of zebrafish(Danio rerio) was studied in acute toxicity environments.Behavioral features were extracted and a method for water quality assessment using support vector machine(SVM) was de-veloped.The behavioral parameters of fish were recorded and analyzed during one hour in an environment of a 24-h half-lethal concentration(LC50) of a pollutant.The data were used to develop a method to evaluate water quality,so as to give an early indication of toxicity.Four kinds of metal ions(Cu2+,Hg2+,Cr6+,and Cd2+) were used for toxicity testing.To enhance the efficiency and accuracy of assessment,a method combining SVM and a genetic algorithm(GA) was used.The results showed that the average prediction accuracy of the method was over 80% and the time cost was acceptable.The method gave satisfactory results for a variety of metal pollutants,demonstrating that this is an effec-tive approach to the classification of water quality.展开更多
Tradeoffs between time complexities and solution optimalities are important when selecting algorithms for an NP-hard problem in different applications. Also, the distinction between theoretical upper bound and actual ...Tradeoffs between time complexities and solution optimalities are important when selecting algorithms for an NP-hard problem in different applications. Also, the distinction between theoretical upper bound and actual solution optimality for realistic instances of an NP-hard problem is a factor in selecting algorithms in practice. We consider the problem of partitioning a sequence of n distinct numbers into minimum number of monotone （increasing or decreasing） subsequences. This problem is NP-hard and the number of monotone subsequences can reach [√2n＋1/1-1/2]in the worst case. We introduce a new algorithm, the modified version of the Yehuda-Fogel algorithm, that computes a solution of no more than [√2n＋1/1-1/2]monotone subsequences in O（n^1.5） time. Then we perform a comparative experimental study on three algorithms, a known approximation algorithm of approximation ratio 1.71 and time complexity O（n^3）, a known greedy algorithm of time complexity O（n^1.5 log n）, and our new modified Yehuda-Fogel algorithm. Our results show that the solutions computed by the greedy algorithm and the modified Yehuda-Fogel algorithm are close to that computed by the approximation algorithm even though the theoretical worst-case error bounds of these two algorithms are not proved to be within a constant time of the optimal solution. Our study indicates that for practical use the greedy algorithm and the modified Yehuda-Fogel algorithm can be good choices if the running time is a major concern.展开更多
In this article,the problem of load balance in hierarchical routing network is studied.Since conventional shortest path first（SPF） algorithm over aggregated topology in hierarchical routing network may result in wor...In this article,the problem of load balance in hierarchical routing network is studied.Since conventional shortest path first（SPF） algorithm over aggregated topology in hierarchical routing network may result in worse routing performance,a traffic sharing path selection algorithm and a variable weight scheme are put forward for hierarchical routing network,which can equilibrate the utilities of link resources and reduce the blocking probability of connections with the improvement on survivability.Simulations are conducted to evaluate proposed variable weight and traffics balance（VWTB） algorithm,which combines traffic sharing and variable weight.From the simulation results,it can be found that the proposed VWTB algorithm can balance the traffics and equilibrate the utilities of link resources significantly.展开更多
基金supported in part by the US National Science Foundation under Grant No. 1205757 Northrop Grumman Corporation
文摘The deployment of underwater networks allows researchers to collect explorative and monitoring data on underwater ecosystems.The acoustic medium has been widely adopted in current research and commercial uses,while the optical medium remains experimental only.According to our survey onthe properties of acoustic and optical communicationsand preliminary simulation results have shown significant trade-offs between bandwidth,propagation delay,power consumption,and effective communication range.We propose a hybrid solution that combines the use of acoustic and optical communication in order to overcome the bandwidth limitation of the acoustic channel by enabling optical communicationwith the help of acoustic-assisted alignment between optical transmitters and receivers.
基金This project is supported by the Cooperative Education Fund of China Ministry of Education(201702113002,201801193119)Hunan Natural Science Foundation(2018JJ2138)+2 种基金Excellent Youth Project of Hunan Education Department(17B096)the H3C Fund of Hunan Internet of Things Federation(20180006)Degree and Graduate Education Reform Project of Hunan Province(JG2018B096).
文摘Nowadays,the number of vehicles in China has increased significantly.The increase of the number of vehicles has also led to the increasingly complex traffic situation and the urgent safety measures in need.However,the existing early warning devices such as geomagnetic,ultrasonic and infrared detection have some shortcomings like difficult installation and maintenance.In addition,geomagnetic detection will damage the road surface,while ultrasonic and infrared detection will be greatly affected by the environment.Considering the shortcomings of the existing solutions,this paper puts forward a solution of early warning for vehicle turning meeting based on image acquisition and microcontrollers.This solution combines image acquisition and processing technology,which uses image sensor to perceive traffic condition and image data analysis algorithm to process perceived image,and then utilize LED display screen to issue an early warning.
文摘We present a network programming mechanism that can flexibly and quickly re-task a large multi-hop network of wireless sensor nodes. Our mechanism allows each sensor node to be incrementally reprogrammed with heterogeneous images of native program code using Rsync block comparison algorithm, point-to-point routing with the BLIP IPv6 stack, and image volume management with Deluge2. With our re-tasking method, we demonstrate an order of magnitude speed-up on small code changes over non-incremental delivery. Our mechanism also scales sub-linearly in the diameter of the network. Collectively, these advancements qualitatively change the software life cycle of the embedded networked systems.
基金Project supported by the Natural Science Foundation of Ningbo City (No.2010A610005)the Key Science and Technology Program of Zhejiang Province (No.2011C11049),China
文摘The behavior of schools of zebrafish(Danio rerio) was studied in acute toxicity environments.Behavioral features were extracted and a method for water quality assessment using support vector machine(SVM) was de-veloped.The behavioral parameters of fish were recorded and analyzed during one hour in an environment of a 24-h half-lethal concentration(LC50) of a pollutant.The data were used to develop a method to evaluate water quality,so as to give an early indication of toxicity.Four kinds of metal ions(Cu2+,Hg2+,Cr6+,and Cd2+) were used for toxicity testing.To enhance the efficiency and accuracy of assessment,a method combining SVM and a genetic algorithm(GA) was used.The results showed that the average prediction accuracy of the method was over 80% and the time cost was acceptable.The method gave satisfactory results for a variety of metal pollutants,demonstrating that this is an effec-tive approach to the classification of water quality.
文摘Tradeoffs between time complexities and solution optimalities are important when selecting algorithms for an NP-hard problem in different applications. Also, the distinction between theoretical upper bound and actual solution optimality for realistic instances of an NP-hard problem is a factor in selecting algorithms in practice. We consider the problem of partitioning a sequence of n distinct numbers into minimum number of monotone （increasing or decreasing） subsequences. This problem is NP-hard and the number of monotone subsequences can reach [√2n＋1/1-1/2]in the worst case. We introduce a new algorithm, the modified version of the Yehuda-Fogel algorithm, that computes a solution of no more than [√2n＋1/1-1/2]monotone subsequences in O（n^1.5） time. Then we perform a comparative experimental study on three algorithms, a known approximation algorithm of approximation ratio 1.71 and time complexity O（n^3）, a known greedy algorithm of time complexity O（n^1.5 log n）, and our new modified Yehuda-Fogel algorithm. Our results show that the solutions computed by the greedy algorithm and the modified Yehuda-Fogel algorithm are close to that computed by the approximation algorithm even though the theoretical worst-case error bounds of these two algorithms are not proved to be within a constant time of the optimal solution. Our study indicates that for practical use the greedy algorithm and the modified Yehuda-Fogel algorithm can be good choices if the running time is a major concern.
基金supported by the Hi-Tech Research and Development Program of China (2007AA01Z252)the National Basic Research Program of China (2007CB310705)+4 种基金the National Natural Science Foundation of China (60711140087, 60772024)the NCET (06-0090)the PCSIRT (IRT0609)the ISTCP (2006DFA11040)the 111 Project of China (B07005)
文摘In this article,the problem of load balance in hierarchical routing network is studied.Since conventional shortest path first（SPF） algorithm over aggregated topology in hierarchical routing network may result in worse routing performance,a traffic sharing path selection algorithm and a variable weight scheme are put forward for hierarchical routing network,which can equilibrate the utilities of link resources and reduce the blocking probability of connections with the improvement on survivability.Simulations are conducted to evaluate proposed variable weight and traffics balance（VWTB） algorithm,which combines traffic sharing and variable weight.From the simulation results,it can be found that the proposed VWTB algorithm can balance the traffics and equilibrate the utilities of link resources significantly.
