A nanopositioning system of both millimetric stroke and nanometric tracking accuracy is a key component for nanofabrication in many applications. In this paper, a novel bi-axial beam-flexure nano servo stage is propos...
详细信息
A nanopositioning system of both millimetric stroke and nanometric tracking accuracy is a key component for nanofabrication in many applications. In this paper, a novel bi-axial beam-flexure nano servo stage is proposed to support a direct writing system for femtosecond laser nanofabrication. The important features of the stage lie in: a mirror symmetric instead of rotational symmetric configuration is adopted to restrict cross axis coupling, and a novel Z-shaped guidance module is proposed to achieve relative large linear stiffness range, in addition a redundant constraints module is introduced to increase off-axis stiffness of the stage. Mechanical analysis and system identification are provided, with which a feedback control algorithm demonstrates the tracking capability for laser fabrication purposes. Based on the fabricated XY nano-stage, real time control and measurements are deployed, demonstrating the millimetric operating workspace and 77.8 nm(RMS) error of tracking a circular trajectory.
In this study, the recall accuracies for different keys on a keyboard were studied and analyzed in a systematic way. It was found that alphabetic keys in the area of "Typing keys" resulted in relatively lowe...
详细信息
ISBN:
(纸本)9789881404763
In this study, the recall accuracies for different keys on a keyboard were studied and analyzed in a systematic way. It was found that alphabetic keys in the area of "Typing keys" resulted in relatively lower recall accuracies than "Function keys", "controlkeys" and "Numeric keys". Besides, there was an absence of significant association between the relative use frequency of English letters and their recall accuracies, confirming to the general expectation that typing tasks rely on the processing of implicit memory rather than explicit memory. Regarding the recall accuracies for numeric keys, participants had higher recall accuracy for the keys located in "Numeric keypad" than those in the "Typing key" area. This might be the result of experience transfer from their daily interaction with devices of similar layout (ATM). Some useful suggestions were provided for the design of a more user-friendly keyboard layout.
This paper studies the makespan minimisation scheduling problem in a two-stage hybrid flow shop. The first stage has one machine and the second stage hasmidentical parallel machines. Neither the processing time nor pr...
详细信息
This paper studies the makespan minimisation scheduling problem in a two-stage hybrid flow shop. The first stage has one machine and the second stage hasmidentical parallel machines. Neither the processing time nor probability distribution of the processing time of each job is uncertain. We propose a robust (min–max regret) scheduling model. To solve the robust scheduling problem, which is NP-hard, we first derive some properties of the worst-case scenario for a given schedule. We then propose both exact and heuristic algorithms to solve this problem. In addition, computational experiments are conducted to evaluate the performance of the proposed algorithms. [ABSTRACT FROM AUTHOR]
作者:
Shu, LeiWu, FengSchool of Management
Key Lab. of the Ministry of Education for Process Control and Efficiency Engineering Experiment Center for the Teaching of Management Education Xi'an Jiaotong University Demo-Center at State Level for Experiment Teaching China
LArising in online environment lately due to frequent dynamic pricing in presence of strategic customer, pulsed demand increases the risk of a retailer as it is large and highly uncertain. Moreover, it shifts between ...
详细信息
LArising in online environment lately due to frequent dynamic pricing in presence of strategic customer, pulsed demand increases the risk of a retailer as it is large and highly uncertain. Moreover, it shifts between periods because of customer strategic behavior. This paper, from the perspective of a risk-averse retailer, establishes a procurement model and a strategic customer demand model, to analyze the effects of strategic customer, pricing and risk aversion on order quantity, profit and risk. Some useful conclusions for procurement risk control are drawn in the setting of two-period. Selling price of period 1 affects order quantity of period 2, when strategic customer ratio is independent of prices;while all selling prices affect all order quantities when dependent. Order quantity in period 1 (period 2) decreases (increases) in strategic customer ratio, which would be less sensitive when the retailer is more risk-averse. Besides, risk-aversion procurement can effectively and significantly mitigate risk without much loss of profit, especially when strategic customer ratio is large.
Milling cutters with fir-slot (fir tree cutters) are widely used in the high speed machining of blade-root and rotor-groove. The complicated structures and multitudinous specification sizes make it difficult to achiev...
详细信息
With network externality, two licensing modes-perpetual licensing mode and Softwareas-a-Service mode, and four compatibility choices-no compatibility, backward compatibility, forward compatibility and backward & f...
详细信息
Data entry, one of the basic businesses in service outsourcing, depends much on human resources. The companies need to reasonably choose and arrange staffs in order to deliver data production in time. In consideration...
详细信息
In this paper, a discrete mathematical approach to solve scheduling of multi-pipeline systems for petroleum products under demand uncertainty is presented. To deal with the uncertainty, the conditional value-at-risk(C...
详细信息
In this paper, a discrete mathematical approach to solve scheduling of multi-pipeline systems for petroleum products under demand uncertainty is presented. To deal with the uncertainty, the conditional value-at-risk(CVAR) analysis is adopted as a risk measure. Firstly an improved scheduling approach is proposed to model the multi-pipeline system with the consideration of different pipeline segment sizes. The improved formulation is computationally intractable when pipeline segments have distinct capacities. Then the model takes a scenario-based approach to cope with uncertainty in a CVAR framework. Computational results are presented to demonstrate the effectiveness of the proposed approach. All the instances are implemented using CPLEX.
This paper presents an innovative method for rejecting multiple narrow-band disturbances in nano-manipulating servo systems. The proposed control scheme consists of a robust controller and a multiple optimal phase fil...
详细信息
This paper presents an innovative method for rejecting multiple narrow-band disturbances in nano-manipulating servo systems. The proposed control scheme consists of a robust controller and a multiple optimal phase filter structure. The baseline robust controller is synthesized with mixed sensitivity optimization for the purpose of robust stability and servo performance.A novel adaptive digital multiple optimal phase filter structure is then developed with a parallel connection, such that online estimation and suppression of the narrow-band disturbances with unknown or time-varying frequencies can be achieved without sacrificing the stability robustness of the closed-loop systems. The proposed control scheme is evaluated via simulations and implemented on a piezoelectric-actuator driven nanopositioner, where high precision positioning is demonstrated in the presence of both unmodeled dynamics and multiple disturbances.
暂无评论