This paper extends the previously developed method of optimizing Road Weather Information Systems(RWIS)station placement by unveiling a sophisticated multi-variable semivariogram model that concurrently considers mult...This paper extends the previously developed method of optimizing Road Weather Information Systems(RWIS)station placement by unveiling a sophisticated multi-variable semivariogram model that concurrently considers multiple vital road weather variables.Previous research primarily centered on single-variable analysis focusing on road surface temperature(RST).The study bridges this oversight by introducing a framework that integrates multiple critical weather variables into the RWIS location allocation framework.This novel approach ensures balanced and equitable RWIS distribution across zones and aligns the network with areas both prone to traffic accidents and areas of high uncertainty.To demonstrate the effectiveness of this refinement,the authors applied the framework to Maine’s existing RWIS network,conducted a gap analysis through varying planning scenarios and generated optimal solutions using a heuristic optimization algorithm.The analysis identified areas that would benefit most from additional RWIS stations and guided optimal resource utilization across different road types and priority locations.A sensitivity analysis was also performed to evaluate the effect of different weightings for weather and traffic factors on the selection of optimal locations.The location solutions generated have been adopted by MaineDOT for future implementations,attesting to the model’s practicality and signifying an important advancement for more effective management of road weather conditions.展开更多
This paper presents a mathematical model that analyzes the throughput of the IEEE 802.11b distributed coordination function （DCF） with the collision aware rate adaptation （CARA） algorithm. IEEE 802.11 WLANs provid...This paper presents a mathematical model that analyzes the throughput of the IEEE 802.11b distributed coordination function （DCF） with the collision aware rate adaptation （CARA） algorithm. IEEE 802.11 WLANs provide multiple transmission rates to improve system throughput by adapting the transmission rate to the current channel conditions. The system throughput is determined by some stations using low transmission rates due to bad channel conditions. CARA algorithm does not disturb the existing IEEE 802.11b formats and it can be easily incorporated into the commercial wireless local area networks （WLAN） devices. Finally, we verify our findings with simulation.展开更多
In this work,we studied the adsorption of modified cellulose nanocrystals onto solid surfaces by quartz crystal microbalance with dissipation monitoring(QCM-D).Cellulose nanocrystals obtained from tunicate(CNC)were mo...In this work,we studied the adsorption of modified cellulose nanocrystals onto solid surfaces by quartz crystal microbalance with dissipation monitoring(QCM-D).Cellulose nanocrystals obtained from tunicate(CNC)were modified at reducing end by amidation reactions.Two different functionalities were investigated:a polyamine dendrimer(CNC-NH_(2)),which interacts with gold surface by the amine groups;and a biotin moiety(CNC-Biot),which has a strong affinity for the protein streptavidin(SAV).QCM-D results revealed different adsorption behaviors between modified and unmodified CNCs.Hence,unmodified CNCs covered almost all the surface forming a rigid and flat layer whereas reducing end modified CNCs remained rather upright forming a hydrated and viscoelastic layer with lower surface coverage.The analysis of adsorption kinetics allowed the calculation of an apparent collision rate factor,which resulted 10-fold higher for unmodified CNCs compared to reducing end modified CNCs,therefore,demonstrating the different adsorption behavior.展开更多
In Cognitive Radio(CR) networks,CR user has to detect the spectrum channel periodically to make sure that the channel is idle during data transmission frame in order to avoid the collisions to the primary users.Hence ...In Cognitive Radio(CR) networks,CR user has to detect the spectrum channel periodically to make sure that the channel is idle during data transmission frame in order to avoid the collisions to the primary users.Hence recent research has been focused on the interference avoidance problem.Quality of Service(QoS) requirement of CR user will affect the time of data transmission in each frame.In this paper,in order to solve the interference avoidance and spectrum utilization problems without cooperation among CR users,a new scheme to obtain the optimal duration of data transmission frame is proposed to maximize the spectrum utilization and guarantee the protection to the primary users.The main advantages of our proposed scheme include the followings:(1) QoS requirement of CR user is concerned;(2) p-persistent Media Access Control(MAC) random access is used to avoid the collisions among CR users;(3) CR network system capacity is considered.We develop a Markov chain of the primary spectrum channel states and an exponential distribution of the CR user's traffic model to analyze the performance of our proposed scheme.Computer simulation shows that there is an optimal data transmission time to maximize the spectrum utilization.However,the regulatory constraint of the collision rate to the primary users has to be satisfied at the expense of spectrum utilization.And also the tradeoff between the spectrum utilization and the capacity of the CR system is taken into account.展开更多
基金supported by a grant from the MaineDOT and Vanasse Hangen Brustlin(VHB).Grant number:VHB 52874.03 WIN 026140.00,Name of the author who received the funding:Tae J.Kwon.
文摘This paper extends the previously developed method of optimizing Road Weather Information Systems(RWIS)station placement by unveiling a sophisticated multi-variable semivariogram model that concurrently considers multiple vital road weather variables.Previous research primarily centered on single-variable analysis focusing on road surface temperature(RST).The study bridges this oversight by introducing a framework that integrates multiple critical weather variables into the RWIS location allocation framework.This novel approach ensures balanced and equitable RWIS distribution across zones and aligns the network with areas both prone to traffic accidents and areas of high uncertainty.To demonstrate the effectiveness of this refinement,the authors applied the framework to Maine’s existing RWIS network,conducted a gap analysis through varying planning scenarios and generated optimal solutions using a heuristic optimization algorithm.The analysis identified areas that would benefit most from additional RWIS stations and guided optimal resource utilization across different road types and priority locations.A sensitivity analysis was also performed to evaluate the effect of different weightings for weather and traffic factors on the selection of optimal locations.The location solutions generated have been adopted by MaineDOT for future implementations,attesting to the model’s practicality and signifying an important advancement for more effective management of road weather conditions.
文摘This paper presents a mathematical model that analyzes the throughput of the IEEE 802.11b distributed coordination function （DCF） with the collision aware rate adaptation （CARA） algorithm. IEEE 802.11 WLANs provide multiple transmission rates to improve system throughput by adapting the transmission rate to the current channel conditions. The system throughput is determined by some stations using low transmission rates due to bad channel conditions. CARA algorithm does not disturb the existing IEEE 802.11b formats and it can be easily incorporated into the commercial wireless local area networks （WLAN） devices. Finally, we verify our findings with simulation.
基金French National Research Agency(Project Cellmach,ANR-17-CE07-0010-01)Region Pays de la Loire(Project Nanomach,Etoiles Montantes 2017-10691).
文摘In this work,we studied the adsorption of modified cellulose nanocrystals onto solid surfaces by quartz crystal microbalance with dissipation monitoring(QCM-D).Cellulose nanocrystals obtained from tunicate(CNC)were modified at reducing end by amidation reactions.Two different functionalities were investigated:a polyamine dendrimer(CNC-NH_(2)),which interacts with gold surface by the amine groups;and a biotin moiety(CNC-Biot),which has a strong affinity for the protein streptavidin(SAV).QCM-D results revealed different adsorption behaviors between modified and unmodified CNCs.Hence,unmodified CNCs covered almost all the surface forming a rigid and flat layer whereas reducing end modified CNCs remained rather upright forming a hydrated and viscoelastic layer with lower surface coverage.The analysis of adsorption kinetics allowed the calculation of an apparent collision rate factor,which resulted 10-fold higher for unmodified CNCs compared to reducing end modified CNCs,therefore,demonstrating the different adsorption behavior.
基金Supported by the National Natural Science Foundation of China (No. 61171094,61001077,61071092)973 Program(2007 CB310607)National Science & Technology Key Project (2011ZX03001-006-02,2011ZX03005-004-03)
文摘In Cognitive Radio(CR) networks,CR user has to detect the spectrum channel periodically to make sure that the channel is idle during data transmission frame in order to avoid the collisions to the primary users.Hence recent research has been focused on the interference avoidance problem.Quality of Service(QoS) requirement of CR user will affect the time of data transmission in each frame.In this paper,in order to solve the interference avoidance and spectrum utilization problems without cooperation among CR users,a new scheme to obtain the optimal duration of data transmission frame is proposed to maximize the spectrum utilization and guarantee the protection to the primary users.The main advantages of our proposed scheme include the followings:(1) QoS requirement of CR user is concerned;(2) p-persistent Media Access Control(MAC) random access is used to avoid the collisions among CR users;(3) CR network system capacity is considered.We develop a Markov chain of the primary spectrum channel states and an exponential distribution of the CR user's traffic model to analyze the performance of our proposed scheme.Computer simulation shows that there is an optimal data transmission time to maximize the spectrum utilization.However,the regulatory constraint of the collision rate to the primary users has to be satisfied at the expense of spectrum utilization.And also the tradeoff between the spectrum utilization and the capacity of the CR system is taken into account.
