The location of U-turn bays is an important consideration in indirect driveway left-turn treatments.In order to improve the performance of right-turns followed by U-turns（RTUTs）,this study evaluates the impacts of t...The location of U-turn bays is an important consideration in indirect driveway left-turn treatments.In order to improve the performance of right-turns followed by U-turns（RTUTs）,this study evaluates the impacts of the separation distances between driveway exits and downstream U-turn locations on the safety and operational performance of vehicles making RTUTs.Crash data are investigated at 179 selected roadway segments,and travel time data are measured using video cameras at 29 locations in the state of Florida,USA.Crash rate models and travel time models are developed based on data collected in the field.It is found that the separation distance between driveway exits and downstream U-turn locations significantly impacts the safety and operational performance of vehicles making right turns followed by U-turns.Based on the research results,the minimum and optimal separation distances between driveways and U-turn locations under different roadway conditions are determined to facilitate driver use of RTUTs.The results of this study can be used for future intersection improvement projects in China.展开更多
In most studies of tunnel boring machine(TBM)tunnelling, the groundwater pressure was not considered, or was simplified and exerted on the boundary of lining structure. Meanwhile, the leakage, which mainly occurs in t...In most studies of tunnel boring machine(TBM)tunnelling, the groundwater pressure was not considered, or was simplified and exerted on the boundary of lining structure. Meanwhile, the leakage, which mainly occurs in the segment joints, was often ignored in the relevant studies of TBM tunnelling. Additionally, the geological models in these studies were simplified to different extents, and mostly were simplified as homogenous bodies. Considering the deficiencies above, a 3D refined model of the surrounding rock of a tunnel is firstly established using NURBS-TIN-BRe P hybrid data structure in this paper. Then the seepage field of the surrounding rock considering the leakage in the segment joints is simulated. Finally, the stability of TBM water diversion tunnel is studied coupled with the seepage simulation, to analyze the stress-strain conditions, the axial force and the bending moment of tunnel segment considering the leakage in the segment joints. The results illustrate that the maximum radial displacement, the minimum principal stress, the maximum principal stress and the axial force of segment lining considering the seepage effect are all larger than those disregarding the seepage effect.展开更多
Based on the conductance fluctuation signals measured from vertical upward oil-gas-water three-phase flow experiment, time frequency representation and surrogate data method were used to investigate dynamical characte...Based on the conductance fluctuation signals measured from vertical upward oil-gas-water three-phase flow experiment, time frequency representation and surrogate data method were used to investigate dynamical characteristics of oil-in-water type bubble and slug flows. The results indicate that oil-in-water type bubble flow will turn to deterministic motion with the increase of oil phase fraction f o and superficial gas velocity U sg under fixed flowrate of oil-water mixture Q mix . The dynamics of oil-in-water type slug flow becomes more complex with the increase of U sg under fixed flowrate of oil-water mixture. The change of f o leads to irregular influence on the dynamics of slug flow. These interesting findings suggest that the surrogate data method can be a faithful tool for characterizing dynamic characteristics of oil-in-water type bubble and slug flows.展开更多
Privacy is becoming one of the most notable challenges threatening wireless sensor networks(WSNs).Adversaries may use RF(radio frequency) localization techniques to perform hop-by-hop trace back to the source sensor&#...Privacy is becoming one of the most notable challenges threatening wireless sensor networks(WSNs).Adversaries may use RF(radio frequency) localization techniques to perform hop-by-hop trace back to the source sensor's location.A multiple k-hop clusters based routing strategy(MHCR) is proposed to preserve source-location privacy as well as enhance energy efficiency for WSNs.Owing to the inherent characteristics of intra-cluster data aggregation,each sensor of the interference clusters is able to act as a fake source to confuse the adversary.Moreover,dummy traffic could be filtered efficiently by the cluster heads during the data aggregation,ensuring no energy consumption be burdened in the hotspot of the network.Through careful analysis and calculation on the distribution and the number of interference clusters,energy efficiency is significantly enhanced without reducing the network lifetime.Finally,the security and delay performance of MHCR scheme are theoretically analyzed.Extensive analysis and simulation results demonstrate that MHCR scheme can improve both the location privacy security and energy efficiency markedly,especially in large-scale WSNs.展开更多
The information extracted from monitoring of rotary blasthole drills helps to optimize the overall mining operation. Rock hardness, drillability, blastability and specific energy of drilling are examples of parameters...The information extracted from monitoring of rotary blasthole drills helps to optimize the overall mining operation. Rock hardness, drillability, blastability and specific energy of drilling are examples of parameters that have been estimated in the past using measurement while drilling techniques. In order to be able to properly utilize measurement while drilling techniques, it is important to properly collect, analyze and interpret extracted data. This paper deals with processing of measurement while drilling data such as rate of penetration, rotary speed, rotary torque and pulldown force collected from rotary blasthole drills.Different methods are discussed to calculate a true rate of penetration which is the most important monitored drill variable for use in rock mass characterization. Then specific energy of drilling is defined and calculated based on electrical and mechanical inputs and the results are compared. The results show that specific energy of drilling can be estimated using the drill's primary drive systems' electrical responses with good accuracy when compared to values based on mechanical inputs.展开更多
In order to improve the practical approach to clinical diagnosis of subclinical mastitis, 72 dairy cattle from KPSBU Lembang Bandung Regency was used in this research. The purpose of this research was to study the cor...In order to improve the practical approach to clinical diagnosis of subclinical mastitis, 72 dairy cattle from KPSBU Lembang Bandung Regency was used in this research. The purpose of this research was to study the correlation between udder length and lactation period with the profile of subclinical mastitis. Lactation period data was collected from interviews with farmers. Subclinical mastitis testing by IPB-1 Mastitis Test reagent and udder length measured using measuring tape （cm）. Data was analyzed using Duncan test and logistic regression. The highest correlation of subclinical mastitis occurred to dairy cattle with average udder length of 7.5 cm and was in the third and forth lactation period. This result shows that udder length and lactation period of dairy cattle is a predisposing factor for subclinical mastitis. This finding is important to improve the milking management as well as a way to diagnose subclinical mastitis.展开更多
OBJECTIVE:To conduct a systematic review to assess the clinical effectiveness of scalp acupuncture(SA) for stroke.METHODS:Literature searches were performed in7 databases up to 16 August 2014,and all the randomized co...OBJECTIVE:To conduct a systematic review to assess the clinical effectiveness of scalp acupuncture(SA) for stroke.METHODS:Literature searches were performed in7 databases up to 16 August 2014,and all the randomized controlled trials(RCTs) in which SA therapy was administered to stroke patients were selected.Methodological quality was assessed using the Jadad score,the Cochrane risk of bias assessment,and the Standards for Reporting Interventions in Clinical Trials of Acupuncture.RESULTS:Of a total of 2086 papers,21 RCTs were selected.Meta-analysis revealed significant differences in the total efficacy rates of the SA group and the body acupuncture(BA) group vs the medication group(P < 0.002,P < 0.000 001,respectively),the SA plus BA group vs the BA group(P < 0.001);in the motor function of the SA plus BA group vs the BA group(P = 0.077);and in the nerve function of the SA group vs the SA plus BA group(P < 0.0001).CONCLUSION:The results of our systematic review showed that SA therapy may exhibit effects in treatment efficacy and in the recovery of motor and nervous functions in patients with acute to chronic stroke.However,because of the lack of methodological quality,the thoroughly planned clinical studies are still required.展开更多
A cluster-based organization with two phases to separate priority calculation and network activity operations is developed. In the election-state phase, clusters are organized by those nodes with sufficient residual e...A cluster-based organization with two phases to separate priority calculation and network activity operations is developed. In the election-state phase, clusters are organized by those nodes with sufficient residual energy level(REL) that are distributed as evenly as possible in the network. For each network round, each node decides its role(such as, cluster header(CH) or a normal node) and its priority level for activity operation. The priority level also affects the active/sleep scheduling in the node. In the steady-state phase, the positive priority levels of active nodes determine their activity order to avoid transmission collision, and to reduce redundant data transmission and sensing coverage. Since the data reporting to the sink is usually performed by a CH delivery chain, subsidiary CHs are selected to assist with data delivery and to share the loading of CHs. The formulae for computing priority levels are analyzed and verified by the examples with valid parameters. The experimental results show that the two phases efficiently consume node energy and achieve energy savings.展开更多
Anomalies in recent observational data indicate that there might be some "anisotropic hair" generated in an inflation period. To obtain general information about the effects of this anisotropic hair to infla...Anomalies in recent observational data indicate that there might be some "anisotropic hair" generated in an inflation period. To obtain general information about the effects of this anisotropic hair to inflation models, we studied anisotropic inflation models that involve one vector and one scalar using several types of potentials. We determined the general relationship between the degree of anisotropy and the fraction of the vector and scalar fields, and concluded that the anisotropies behave independently of the potentials. We also generalized our study to the case of multi-directional anisotropies.展开更多
文摘The location of U-turn bays is an important consideration in indirect driveway left-turn treatments.In order to improve the performance of right-turns followed by U-turns（RTUTs）,this study evaluates the impacts of the separation distances between driveway exits and downstream U-turn locations on the safety and operational performance of vehicles making RTUTs.Crash data are investigated at 179 selected roadway segments,and travel time data are measured using video cameras at 29 locations in the state of Florida,USA.Crash rate models and travel time models are developed based on data collected in the field.It is found that the separation distance between driveway exits and downstream U-turn locations significantly impacts the safety and operational performance of vehicles making right turns followed by U-turns.Based on the research results,the minimum and optimal separation distances between driveways and U-turn locations under different roadway conditions are determined to facilitate driver use of RTUTs.The results of this study can be used for future intersection improvement projects in China.
基金Supported by the Foundation for Innovation Research Groups of the National Natural Science Foundation of China(No.51321065)Tianjin Research Program of Application Foundation and Advanced Technology(No.12JCZDJC29200)Tianjin Natural Science Foundation(No.13JCYBJC19500)
文摘In most studies of tunnel boring machine(TBM)tunnelling, the groundwater pressure was not considered, or was simplified and exerted on the boundary of lining structure. Meanwhile, the leakage, which mainly occurs in the segment joints, was often ignored in the relevant studies of TBM tunnelling. Additionally, the geological models in these studies were simplified to different extents, and mostly were simplified as homogenous bodies. Considering the deficiencies above, a 3D refined model of the surrounding rock of a tunnel is firstly established using NURBS-TIN-BRe P hybrid data structure in this paper. Then the seepage field of the surrounding rock considering the leakage in the segment joints is simulated. Finally, the stability of TBM water diversion tunnel is studied coupled with the seepage simulation, to analyze the stress-strain conditions, the axial force and the bending moment of tunnel segment considering the leakage in the segment joints. The results illustrate that the maximum radial displacement, the minimum principal stress, the maximum principal stress and the axial force of segment lining considering the seepage effect are all larger than those disregarding the seepage effect.
基金Supported by the National Natural Science Foundation of China (50974095, 41174109)Gao Zhongke (高忠科) was also supported by the National Natural Science Foundation of China (61104148)+2 种基金the National Science and Technology Major Projects (2011ZX05020-006)Specialized Research Fund for the Doctoral Program of Higher Education of China(20110032120088)the Independent Innovation Foundation of Tianjin University
文摘Based on the conductance fluctuation signals measured from vertical upward oil-gas-water three-phase flow experiment, time frequency representation and surrogate data method were used to investigate dynamical characteristics of oil-in-water type bubble and slug flows. The results indicate that oil-in-water type bubble flow will turn to deterministic motion with the increase of oil phase fraction f o and superficial gas velocity U sg under fixed flowrate of oil-water mixture Q mix . The dynamics of oil-in-water type slug flow becomes more complex with the increase of U sg under fixed flowrate of oil-water mixture. The change of f o leads to irregular influence on the dynamics of slug flow. These interesting findings suggest that the surrogate data method can be a faithful tool for characterizing dynamic characteristics of oil-in-water type bubble and slug flows.
基金Project(2013DFB10070)supported by the International Science & Technology Cooperation Program of ChinaProject(2012GK4106)supported by the Hunan Provincial Science & Technology Program,ChinaProject(12MX15)supported by the Mittal Innovation Project of Central South University,China
文摘Privacy is becoming one of the most notable challenges threatening wireless sensor networks(WSNs).Adversaries may use RF(radio frequency) localization techniques to perform hop-by-hop trace back to the source sensor's location.A multiple k-hop clusters based routing strategy(MHCR) is proposed to preserve source-location privacy as well as enhance energy efficiency for WSNs.Owing to the inherent characteristics of intra-cluster data aggregation,each sensor of the interference clusters is able to act as a fake source to confuse the adversary.Moreover,dummy traffic could be filtered efficiently by the cluster heads during the data aggregation,ensuring no energy consumption be burdened in the hotspot of the network.Through careful analysis and calculation on the distribution and the number of interference clusters,energy efficiency is significantly enhanced without reducing the network lifetime.Finally,the security and delay performance of MHCR scheme are theoretically analyzed.Extensive analysis and simulation results demonstrate that MHCR scheme can improve both the location privacy security and energy efficiency markedly,especially in large-scale WSNs.
文摘The information extracted from monitoring of rotary blasthole drills helps to optimize the overall mining operation. Rock hardness, drillability, blastability and specific energy of drilling are examples of parameters that have been estimated in the past using measurement while drilling techniques. In order to be able to properly utilize measurement while drilling techniques, it is important to properly collect, analyze and interpret extracted data. This paper deals with processing of measurement while drilling data such as rate of penetration, rotary speed, rotary torque and pulldown force collected from rotary blasthole drills.Different methods are discussed to calculate a true rate of penetration which is the most important monitored drill variable for use in rock mass characterization. Then specific energy of drilling is defined and calculated based on electrical and mechanical inputs and the results are compared. The results show that specific energy of drilling can be estimated using the drill's primary drive systems' electrical responses with good accuracy when compared to values based on mechanical inputs.
文摘In order to improve the practical approach to clinical diagnosis of subclinical mastitis, 72 dairy cattle from KPSBU Lembang Bandung Regency was used in this research. The purpose of this research was to study the correlation between udder length and lactation period with the profile of subclinical mastitis. Lactation period data was collected from interviews with farmers. Subclinical mastitis testing by IPB-1 Mastitis Test reagent and udder length measured using measuring tape （cm）. Data was analyzed using Duncan test and logistic regression. The highest correlation of subclinical mastitis occurred to dairy cattle with average udder length of 7.5 cm and was in the third and forth lactation period. This result shows that udder length and lactation period of dairy cattle is a predisposing factor for subclinical mastitis. This finding is important to improve the milking management as well as a way to diagnose subclinical mastitis.
基金the Convergence of Conventional Medicine and Traditional Korean Medicine R&D Program Funded by the Ministry of Health&Welfare through the Korea Health Industry Development Institute(KHIDI)(No.HI14C0862)
文摘OBJECTIVE:To conduct a systematic review to assess the clinical effectiveness of scalp acupuncture(SA) for stroke.METHODS:Literature searches were performed in7 databases up to 16 August 2014,and all the randomized controlled trials(RCTs) in which SA therapy was administered to stroke patients were selected.Methodological quality was assessed using the Jadad score,the Cochrane risk of bias assessment,and the Standards for Reporting Interventions in Clinical Trials of Acupuncture.RESULTS:Of a total of 2086 papers,21 RCTs were selected.Meta-analysis revealed significant differences in the total efficacy rates of the SA group and the body acupuncture(BA) group vs the medication group(P < 0.002,P < 0.000 001,respectively),the SA plus BA group vs the BA group(P < 0.001);in the motor function of the SA plus BA group vs the BA group(P = 0.077);and in the nerve function of the SA group vs the SA plus BA group(P < 0.0001).CONCLUSION:The results of our systematic review showed that SA therapy may exhibit effects in treatment efficacy and in the recovery of motor and nervous functions in patients with acute to chronic stroke.However,because of the lack of methodological quality,the thoroughly planned clinical studies are still required.
基金the National Natural Science Foundation of China(No.71201172)
文摘A cluster-based organization with two phases to separate priority calculation and network activity operations is developed. In the election-state phase, clusters are organized by those nodes with sufficient residual energy level(REL) that are distributed as evenly as possible in the network. For each network round, each node decides its role(such as, cluster header(CH) or a normal node) and its priority level for activity operation. The priority level also affects the active/sleep scheduling in the node. In the steady-state phase, the positive priority levels of active nodes determine their activity order to avoid transmission collision, and to reduce redundant data transmission and sensing coverage. Since the data reporting to the sink is usually performed by a CH delivery chain, subsidiary CHs are selected to assist with data delivery and to share the loading of CHs. The formulae for computing priority levels are analyzed and verified by the examples with valid parameters. The experimental results show that the two phases efficiently consume node energy and achieve energy savings.
基金supported by the Project of Undergraduates’Training Program for Innovation/VenturingCentral China Normal University(Grant No.B2014179)
文摘Anomalies in recent observational data indicate that there might be some "anisotropic hair" generated in an inflation period. To obtain general information about the effects of this anisotropic hair to inflation models, we studied anisotropic inflation models that involve one vector and one scalar using several types of potentials. We determined the general relationship between the degree of anisotropy and the fraction of the vector and scalar fields, and concluded that the anisotropies behave independently of the potentials. We also generalized our study to the case of multi-directional anisotropies.
