Ultra Wideband (UWB) technology is promising for wireless personal area network (WPAN) applications due to its high data rate, low power requirement and short-range characteristics. Instead of exploring new unused fre...Ultra Wideband (UWB) technology is promising for wireless personal area network (WPAN) applications due to its high data rate, low power requirement and short-range characteristics. Instead of exploring new unused frequency band, the UWB communication follows the overlay principle, i.e., sharing the spectrum with existing systems and devices. This novel radio technology has been recently approved by the regulatory authorities in the United States and Canada, and is being considered for approval in Europe and Asia. In this paper, an overview of the UWB radio technology from the technical, economical, and regulatory perspectives is provided. Firstly, the definition of UWB by the Federal Communications Commission (FCC) is introduced, followed by a brief introduction to the history. The current status of the standardization process resulting from the FCC’s recent decision to permit unlicensed operation in the [3.1 - 10.6] GHz band is discussed. Then, the reasons of considering UWB as a future solution for WLAN/WPAN applications are studied. In particular, the unique properties of UWB and its difference from other wireless technology alternatives are studied. Then, the benefits and challenges related to the commercial deployment of UWB for future applications are discussed. Finally, the research problems and challenges posed by the UWB technology are focused.展开更多
The motivation of this work is to obtain single PI/PID tuning formula for different types of processes with enhanced disturbance rejection performance. The proposed tuning formula consistently gives better performance...The motivation of this work is to obtain single PI/PID tuning formula for different types of processes with enhanced disturbance rejection performance. The proposed tuning formula consistently gives better performance in comparison to several well-known methods at the same degree of robustness for stable, integrating and unstable processes. For the selection of the closed-loop time constant(τc), a guideline is provided over a broad range of time-delay/time-constant ratios on the basis of the peak of maximum sensitivity(Ms). An analysis has been performed for the uncertainty margin with the different process parameters for the robust controller design. It gives the guideline of the Ms-value settings for the PI controller designs based on the process parameters uncertainty. Furthermore, a relationship has been developed between Ms-value and uncertainty margin with the different process parameters(k, τ and θ). Simulation study has been conducted for the broad class of processes and the controllers are tuned to have the same degree of robustness by measuring the maximum sensitivity, Ms, in order to obtain a reasonable comparison.展开更多
The propagation and transformation of an elliptic Gaussian optical beam(EGB) passing through a Kerr-law nonlinear conical graded-index rod lens are presented.In the rod lens, the EGB is treated as two dependent optica...The propagation and transformation of an elliptic Gaussian optical beam(EGB) passing through a Kerr-law nonlinear conical graded-index rod lens are presented.In the rod lens, the EGB is treated as two dependent optical beams.The dimensionless beam-width parameters and the inverses of the curvature radii for the wavefront of the two beams are given semi-analytically,and the transformations of the EGB with the rod lens are derived by use of the ABCD law of Gaussian optical beam.展开更多
Background： Glenohumeral internal rotation deficit （GIRD） is a risk factor for shoulder and elbow injury in baseball players. Although this evidence forms a basis for recommending stretching, clinical measures of i...Background： Glenohumeral internal rotation deficit （GIRD） is a risk factor for shoulder and elbow injury in baseball players. Although this evidence forms a basis for recommending stretching, clinical measures of internal rotation range of motion （ROM） do not differentiate if GIRD is due to muscular, capsuloligamentous, or osseous factors. Understanding the contributions of these structures to GIRD is important for the development of targeted interventions. We hypothesize that the osseous component will have the greatest relative contribution to GIRD, followed by muscle stiffness and posterior capsule thickness. Methods： Internal rotation ROM, muscle stiffness （teres minor, infraspinatus, and posterior deltoid）, posterior capsule thickness, and humeral retrotorsion were evaluated on 156 baseball players. A side-to-side difference was calculated for each variable. Variables were entered into a multivariable linear regression to determine the significant predictors of GIRD. Results： The regression model was statistically significant （R2 = 0.134, F（1, 156） = 24.0, p 〈 0.01） with only humeral retrotorsion difference remaining as a significant predictor （β = -0.243, t156 = -4.9, p 〈 0.01）. A greater humeral retrotorsion side-to-side difference was associated with more GIRD. Conclusion： Humeral retrotorsion accounted for 13.3% of the variance in GIRD. The stiffness of the superficial shoulder muscles and capsular thickness, as measured in this study, were not predictors of GIRD. Factors not assessed in this study, such as deeper muscle stiffness, capsule/ ligament laxity, and neuromuscular regulation of muscle stiffness may also contribute to GIRD. Since it is the largest contributor to GIRD, causes of changes in humeral retrotorsion need to be identified. The osseous component only accounted for 13.3% of the variance in GIRD, indicating a large contribution from soft tissues factors that were not addressed in this study. These factors need to be identified to develop evidence-based evaluations and intervention programs to decrease the risk of injury in baseball players.展开更多
In this paper,a reinforced gradient-type iterative learning control pro file is proposed by making use of system matrices and a proper learning step to improve the tracking performance of batch processes disturbed by ...In this paper,a reinforced gradient-type iterative learning control pro file is proposed by making use of system matrices and a proper learning step to improve the tracking performance of batch processes disturbed by external Gaussian white noise.The robustness is analyzed and the range of the step is speci fied by means of statistical technique and matrix theory.Compared with the conventional one,the proposed algorithm is more ef ficient to resist external noise.Numerical simulations of an injection molding process illustrate that the proposed scheme is feasible and effective.展开更多
An analytical method was developed and validated for determination of patulin in apple puree by HPLC. Extraction and clean-up ofpatulin from clear extract are achieved on AFFINIMIP SPEPATULIN cartridges. Patulin is th...An analytical method was developed and validated for determination of patulin in apple puree by HPLC. Extraction and clean-up ofpatulin from clear extract are achieved on AFFINIMIP SPEPATULIN cartridges. Patulin is then separated on a Hypersil GOLD column 150 mm × 4 mm, 5 μtmand detected at 276 nm. The recovery in the range of 5 μg/kg-80 μg/kg was 81.47%. The limit of detection （LOD） was 1.36 μg/kg, and the limit of quantification （LOQ） was 4.55 μg/kg. The patulin content of the commercial samples of apple puree and samples of apple and fruit puree forinfants and young children as well as the samples of apple puree prepared from two apple varieties intended for processing （Jonathan, Florina） and obtained from conventional and uncertified organic cultures has been evaluated in this paper. The 44.83% patulin concentration of the analyzed samples were under the maximum level of the European Commission Regulation （EC） 1881/2006, in 46.55% of the analyzed samples patulin was not detected and in 8.62% of samples patulin concentration was lower than LOQ （European Comission, 2006a） Patulin was not detected in samples of apple puree intended for infants and young children consumption.展开更多
文摘Ultra Wideband (UWB) technology is promising for wireless personal area network (WPAN) applications due to its high data rate, low power requirement and short-range characteristics. Instead of exploring new unused frequency band, the UWB communication follows the overlay principle, i.e., sharing the spectrum with existing systems and devices. This novel radio technology has been recently approved by the regulatory authorities in the United States and Canada, and is being considered for approval in Europe and Asia. In this paper, an overview of the UWB radio technology from the technical, economical, and regulatory perspectives is provided. Firstly, the definition of UWB by the Federal Communications Commission (FCC) is introduced, followed by a brief introduction to the history. The current status of the standardization process resulting from the FCC’s recent decision to permit unlicensed operation in the [3.1 - 10.6] GHz band is discussed. Then, the reasons of considering UWB as a future solution for WLAN/WPAN applications are studied. In particular, the unique properties of UWB and its difference from other wireless technology alternatives are studied. Then, the benefits and challenges related to the commercial deployment of UWB for future applications are discussed. Finally, the research problems and challenges posed by the UWB technology are focused.
基金the support provided by King Abdulaziz City for Science and Technology (KACST) through the "KACST Annual Program" at King Fahd University of Petroleum & Minerals (KFUPM) for funding this work through project number AT-32-41
文摘The motivation of this work is to obtain single PI/PID tuning formula for different types of processes with enhanced disturbance rejection performance. The proposed tuning formula consistently gives better performance in comparison to several well-known methods at the same degree of robustness for stable, integrating and unstable processes. For the selection of the closed-loop time constant(τc), a guideline is provided over a broad range of time-delay/time-constant ratios on the basis of the peak of maximum sensitivity(Ms). An analysis has been performed for the uncertainty margin with the different process parameters for the robust controller design. It gives the guideline of the Ms-value settings for the PI controller designs based on the process parameters uncertainty. Furthermore, a relationship has been developed between Ms-value and uncertainty margin with the different process parameters(k, τ and θ). Simulation study has been conducted for the broad class of processes and the controllers are tuned to have the same degree of robustness by measuring the maximum sensitivity, Ms, in order to obtain a reasonable comparison.
文摘The propagation and transformation of an elliptic Gaussian optical beam(EGB) passing through a Kerr-law nonlinear conical graded-index rod lens are presented.In the rod lens, the EGB is treated as two dependent optical beams.The dimensionless beam-width parameters and the inverses of the curvature radii for the wavefront of the two beams are given semi-analytically,and the transformations of the EGB with the rod lens are derived by use of the ABCD law of Gaussian optical beam.
文摘Background： Glenohumeral internal rotation deficit （GIRD） is a risk factor for shoulder and elbow injury in baseball players. Although this evidence forms a basis for recommending stretching, clinical measures of internal rotation range of motion （ROM） do not differentiate if GIRD is due to muscular, capsuloligamentous, or osseous factors. Understanding the contributions of these structures to GIRD is important for the development of targeted interventions. We hypothesize that the osseous component will have the greatest relative contribution to GIRD, followed by muscle stiffness and posterior capsule thickness. Methods： Internal rotation ROM, muscle stiffness （teres minor, infraspinatus, and posterior deltoid）, posterior capsule thickness, and humeral retrotorsion were evaluated on 156 baseball players. A side-to-side difference was calculated for each variable. Variables were entered into a multivariable linear regression to determine the significant predictors of GIRD. Results： The regression model was statistically significant （R2 = 0.134, F（1, 156） = 24.0, p 〈 0.01） with only humeral retrotorsion difference remaining as a significant predictor （β = -0.243, t156 = -4.9, p 〈 0.01）. A greater humeral retrotorsion side-to-side difference was associated with more GIRD. Conclusion： Humeral retrotorsion accounted for 13.3% of the variance in GIRD. The stiffness of the superficial shoulder muscles and capsular thickness, as measured in this study, were not predictors of GIRD. Factors not assessed in this study, such as deeper muscle stiffness, capsule/ ligament laxity, and neuromuscular regulation of muscle stiffness may also contribute to GIRD. Since it is the largest contributor to GIRD, causes of changes in humeral retrotorsion need to be identified. The osseous component only accounted for 13.3% of the variance in GIRD, indicating a large contribution from soft tissues factors that were not addressed in this study. These factors need to be identified to develop evidence-based evaluations and intervention programs to decrease the risk of injury in baseball players.
基金Supported by National Natural Science Foundation of China(F010114-6097414061273135)
文摘In this paper,a reinforced gradient-type iterative learning control pro file is proposed by making use of system matrices and a proper learning step to improve the tracking performance of batch processes disturbed by external Gaussian white noise.The robustness is analyzed and the range of the step is speci fied by means of statistical technique and matrix theory.Compared with the conventional one,the proposed algorithm is more ef ficient to resist external noise.Numerical simulations of an injection molding process illustrate that the proposed scheme is feasible and effective.
文摘An analytical method was developed and validated for determination of patulin in apple puree by HPLC. Extraction and clean-up ofpatulin from clear extract are achieved on AFFINIMIP SPEPATULIN cartridges. Patulin is then separated on a Hypersil GOLD column 150 mm × 4 mm, 5 μtmand detected at 276 nm. The recovery in the range of 5 μg/kg-80 μg/kg was 81.47%. The limit of detection （LOD） was 1.36 μg/kg, and the limit of quantification （LOQ） was 4.55 μg/kg. The patulin content of the commercial samples of apple puree and samples of apple and fruit puree forinfants and young children as well as the samples of apple puree prepared from two apple varieties intended for processing （Jonathan, Florina） and obtained from conventional and uncertified organic cultures has been evaluated in this paper. The 44.83% patulin concentration of the analyzed samples were under the maximum level of the European Commission Regulation （EC） 1881/2006, in 46.55% of the analyzed samples patulin was not detected and in 8.62% of samples patulin concentration was lower than LOQ （European Comission, 2006a） Patulin was not detected in samples of apple puree intended for infants and young children consumption.
