Direct Compensation Research Articles

Research on the application of Edlén’s formulation in compensation for ultra-precision motion platform’s measurement using an interferometer

The measurement accuracy of an interferometer is largely affected by the refractive index of air. Compared with the direct compensation method, the indirect compensation method is more suitable for compensation for an ultra-precision motion platform using an interferometer. However, the indirect compensation method depends on the air refractive index’s formula, which is empirical and not entirely accurate. It seems that the application of the indirect compensation method in a high-precision measured object is hampered. Considering that the repeat positioning accuracy of some application objects such as lithography’s ultra-precision platform is the highest requirement while the positioning accuracy is less demanding, this means that repeat measuring accuracy is the main factor. For these objects, this paper proposed a hypothesis of Birch and Downs’s revised Edlén’s formula firstly and derived the relation between the repeat measuring accuracy and the repeatability of environmental parameters on this basis when an indirect compensation method was used. An example on the analysis of the difference between Bonsch and Potulski’s further revised formula and Birch and Downs’s revised Edlén’s formula explains the rationality of the hypothesis. In addition, a simulation result on the lithography mask stage’s flow field showed that the indirect compensation method can achieve sub-nanometer repeat measuring accuracy and it meets repeat positioning accuracy’s requirement in lithography.

Robust Control With Exact Uncertainties Compensation: With or Without Chattering?

The problem of robust exact output control for linear systems with smooth bounded matched unknown inputs is considered. The higher order sliding mode observers provide both theoretically exact observation and unknown input identification. In this paper, a methodology is proposed to select the most adequate output control strategy for matched perturbations compensation. The aim of this paper is to investigate the possibility for exact uncertainties compensation using signals identified by high order sliding mode observers. Towards this aim, we modify the hierarchical super-twisting observer in order to have the best observation and identification accuracy possible. Then, two controllers are compared. The first one is an integral sliding mode controller based on the observed values of the state variables. The other strategy is based on the direct compensation of matched perturbations using their identified values. The performance of both controllers is estimated in terms of the deterministic noise upper bounds, sampling step and execution time. Based on these estimations, the designer may select the proper controller for the system. Experimental results are given for an inverted rotary pendulum system.

An interferometric calibration system for various linear artefacts using active compensation of angular motion errors

A calibration system for linear-dimension artefacts was developed, which employed a multi-axis laser interferometer for direct metrological traceability and active compensation of angular motion errors. It can calibrate various end and line standards by changing probes (contact and optical probe). We designed the system as a moving probe type with a cantilever structure to reduce overall size and increase efficiency in calibration. A stage part including a two-axis tilt stage provides precise linear motion of a probing part over the range of 2000 mm with nanometric resolution. The three-axis interferometer measuring linear and rotational motions of the stage enables us to obtain probing position and compensate angular motion errors precisely. It was also arranged to minimize the Abbe offset, and so the Abbe error can be reduced remarkably combining the active compensation of angular motion errors. The overall system was installed in a temperature-controlled chamber to decrease thermal variation during measurements. The measurement uncertainty of the calibration system was analysed by considering the performance of the main components. We measured several long gauge blocks and a precision line scale, and compared the measured values with the reference ones and also checked their stabilities. Their deviations were less than 100 nm and existed within the expanded measurement uncertainty (k = 2).

Emerging issues under interim final regulation on plan service provider fee disclosure

PurposeThe purpose of this paper is to describe interpretive and compliance issues arising under the Labor Department's interim final regulations under the statutory exemption for the provision of services provided by Section 408(b)(2) of ERISA, which will become effective on January 1, 2012.Design/methodology/approachThe paper analyzes the published interim final regulations and considers significant comments filed in response to the proposed regulations.FindingsEffective January 1, 2012, covered service providers who rely on the statutory exemption for the provision of services provided by Section 408(b)(2) must begin complying with the interim final amendments to the regulations under Section 408(b)(2) (the “Regulation”). Among other changes, the Regulation will require service providers to provide additional disclosures of direct and indirect compensation and to identify whether they expect that they will be providing services as a fiduciary or as a registered investment adviser. The primary purpose of the Regulation is to assist plan sponsors in evaluating service provider relationships, including total compensation that will be received by the service provider and conflicts of interests to which the service provider may be subject. The Regulation will apply to both new and existing service provider arrangements on January 1, 2012. Failure to comply with the Regulation may result in the assessment of excise taxes under Section 4975 of the Internal Revenue Code unless other exemptive relief is available. Service provider arrangements may be eligible for exemptive relief under certain other statutory and administrative exemptions.Originality/valueThe paper describes possible compliance issues that may arise under the Regulation and identifies and evaluates interpretive and compliance issues that have been noted since the proposed amendments were published.

Stochastic finite-element modelling and optimization for net-shape forging of three-dimensional aero-engine blades

The stochastic nature of the forging process is a key influencing factor for achievable dimensional and shape accuracy of forged aerofoil blades for aero-engine applications. In this article, a finite-element-based stochastic modelling and optimization method is presented for net-shape forging of three-dimensional (3D) aerofoil blades. A combined Monte Carlo simulation and response surface method as well as the first-order second-moment reliability method are developed to quantify the stochastic characteristics of forging errors due to uncertainties of process parameters and forging conditions. A two-step optimization approach is presented to minimize systematic errors using a direct compensation method and to reduce random variations through a variance control procedure. A 3D blade forging case study is presented to evaluate the stochastic characteristics of the dimensional errors of forged aerofoil blades in comparison with measurement data and to demonstrate much improved forging accuracy using the proposed stochastic optimization method. The results from the case study also suggest that the stochastic-based optimization method may be easily applied to other metal-forming processes.

Stochastic finite-element modelling and optimization for net-shape forging of three-dimensional aero-engine blades

The stochastic nature of the forging process is a key influencing factor for achievable dimensional and shape accuracy of forged aerofoil blades for aero-engine applications. In this article, a finite-element-based stochastic modelling and optimization method is presented for net-shape forging of three-dimensional (3D) aerofoil blades. A combined Monte Carlo simulation and response surface method as well as the first-order second-moment reliability method are developed to quantify the stochastic characteristics of forging errors due to uncertainties of process parameters and forging conditions. A two-step optimization approach is presented to minimize systematic errors using a direct compensation method and to reduce random variations through a variance control procedure. A 3D blade forging case study is presented to evaluate the stochastic characteristics of the dimensional errors of forged aerofoil blades in comparison with measurement data and to demonstrate much improved forging accuracy using the proposed stochastic optimization method. The results from the case study also suggest that the stochastic-based optimization method may be easily applied to other metal-forming processes.

Improving Antimicrobial Stewardship The Evolution of Programmatic Strategies and Barriers

To describe the prevalence and characteristics of antimicrobial stewardship programs (ASPs) in hospitals across the United States and to describe financial support provided for these programs. Electronic and paper 14-question survey of infectious diseases physician members of the Infectious Diseases Society of America Emerging Infections Network (IDSA EIN). All 1,044 IDSA EIN members who care for adult patients were invited to participate. Five hundred twenty-two (50%) members responded. Seventy-three percent of respondents reported that their institutions had or were planning an ASP, compared with 50% reporting the same thing in an EIN survey 10 years before. A shift was noted from formulary restriction alone to use of a set of tailored strategies designed to provide information and feedback to prescribers, particularly in community hospitals. Lack of funding and lack of personnel were reported as major barriers to implementing a program. Fifty-two percent of respondents with an ASP reported that infectious diseases physicians do not receive direct compensation for their participation in the ASP, compared with 18% 10 years ago. The percentage of institutions reporting ASPs has increased over the last decade, although small community hospitals were least likely to have these programs. In addition, ASP strategies have shifted dramatically. Lack of funding remains a key barrier for ASPs, and administrators need additional cost savings data in order to support ASPs. Interestingly, while guidelines and editorials regard compensated participation by an infectious diseases physician in these programs as critical, we found that more than half of the respondents reported no direct compensation for ASP activities.

Juvenile Songbirds Compensate for Displacement to Oceanic Islands during Autumn Migration

To what degree juvenile migrant birds are able to correct for orientation errors or wind drift is still largely unknown. We studied the orientation of passerines on the Faroe Islands far off the normal migration routes of European migrants. The ability to compensate for displacement was tested in naturally occurring vagrants presumably displaced by wind and in birds experimentally displaced 1100 km from Denmark to the Faroes. The orientation was studied in orientation cages as well as in the free-flying birds after release by tracking departures using small radio transmitters. Both the naturally displaced and the experimentally displaced birds oriented in more easterly directions on the Faroes than was observed in Denmark prior to displacement. This pattern was even more pronounced in departure directions, perhaps because of wind influence. The clear directional compensation found even in experimentally displaced birds indicates that first-year birds can also possess the ability to correct for displacement in some circumstances, possibly involving either some primitive form of true navigation, or ‘sign posts’, but the cues used for this are highly speculative. We also found some indications of differences between species in the reaction to displacement. Such differences might be involved in the diversity of results reported in displacement studies so far.

CEO Compensation and Firm Performance: an Empirical Investigation of UK Panel Data

Abstract This paper examines the link between CEO pay and performance employing a unique, hand‐collected panel data set of 390 UK non‐financial firms from the FTSE All Share Index for the period 1999–2005. We include both cash (salary and bonus) and equity‐based (stock options and long‐term incentive plans) components of CEO compensation, and CEO wealth based on share holdings, stock option and stock awards holdings in our analysis. In addition, we control for a comprehensive set of corporate governance variables. The empirical results show that in comparison to the previous findings for US CEOs, pay‐performance elasticity for UK CEOs seems to be lower; pay‐performance elasticity for UK CEOs is 0.075 (0.095) for cash compensation (total direct compensation), indicating that a ten percentage increase in shareholder return corresponds to an increase of 0.75% (0.95%) in cash (total direct) compensation. We also find that both the median share holdings and stock‐based pay‐performance sensitivity are lower for UK CEOs when we compare our findings with the previous findings for US CEOs. Thus, our results suggest that corporate governance reports in the UK, such as the Greenbury Report (1995) that proposed CEO compensation be more closely linked to performance, have not been totally effective. Our findings also indicate that institutional ownership has a positive and significant influence on CEO pay‐performance sensitivity of option grants. Finally, we find that longer CEO tenure is associated with lower pay‐performance sensitivity of option grants suggesting the entrenchment effect of CEO tenure.

The Economic Impact Of International Trade In A Small Regional Economy: The Case Of Miami, Florida

This study estimates the economic impacts from international trade activity in Miami-Dade using an input-output model developed with IMPLAN software. Common observations suggest that international trade is an important determinant of the long-term economic growth of the metro areas economy, as well as a key factor in the regions pattern of short-run business cycles. The logistics of international trade requires not only port operations, but also involves numerous components of the transportation network. Local manufacturing firms are also likely to be involved in exporting or production requiring imported intermediate goods. BLS establishment survey data is used to identify the direct employment and labor compensation in industries that are directly involved in the movement of international cargo. Census data on origin of exports is used to estimate the direct impact of international trade related local manufacturing. An economic model for Miami-Dade County is then used to estimate the local indirect and induced impacts of international merchandise trade.

Next Generation Mold Level Control: Development of LevCon 2.0

Siemens VAI develops the next generation of the successful mold level controller LevCon. The new controller uses the most modern control principles from optimal control theory while being robust enough to operate in the difficult conditions of a steel work. One prerequisite for the application of modern control theory is a good mathematical model of the process. In the past, the models used for mold level control design were quite simple, neglecting some of the important limiting factors such as surface resonance waves of the mold level. For the derivation of a resonance surface wave model, extensive water model trials have been carried out. With the help of the plant model, modern control theory is applied and a mathematically optimal controller feedback is designed. It offers an increased disturbance rejection compared to earlier algorithms, which is significantly reducing the mold level deviation due to disturbances as, e.g., unclogging events. However, there are still disturbances that cannot be eliminated completely, like mold level hunting caused by instationary bulging. In the past, mold level hunting was reported to be a very slow disturbance with a wavelength of approximately one roller pitch and a frequency below 0.1 Hz. During the development work, it turned out that also higher harmonics of this base frequency exist with wavelengths of 1/2, 1/3, up to 1/7 of the roller pitch. These high frequency fluctuations cannot be eliminated by feedback control only. However, an additional feed-forward loop which utilizes the withdrawal drives power for direct compensation of the mold level hunting steel flow is developed. With this approach, it is possible to reduce even fast mold level hunting.

The Direct Pulse Compensation of Dead-time of APF

As the presence of the dead time of switching device, the compensation current of the inverter will have errors, and the compensation effect of active power filter becomes poor. For the fixed switching cycle of space vector current control and symmetrical PWM pulse, proposed a direct pulse compensation method of dead-time .It offsets the impact of dead time by superimposed a square wave on the triangular carrier which compared to the IGBT switching time, the triangular carrier and the square wave have the same frequency, and the amplitude of square wave is equal to dead time. The method is very simple and effective. MATLAB simulation shows that the method basically achieves full compensation of dead time.

Adaptive Failure Compensation Control with Redundant Actuators⋆

AbstractRedundant actuators are commonly used for actuator failure compensation but bring new challenges for feedback control design as uncertain failures can introduce large structural, parametric and actuation uncertainties. Two key technical issues are associated with using redundant actuators: how to coordinate redundant actuators for effective feedback control, and how to adaptively compensate uncertain actuator failures. In this paper, we present a systematic overview of direct adaptive failure compensation based solutions to these issues for different types of control systems: state tracking and output tracking, using state feedback or output feedback, for linear and nonlinear systems.

Direct current ripple compensation for multi-phase fault-tolerant machines

A second-harmonic direct current (DC) ripple compensation technique is presented for a multi-phase, fault-tolerant, permanent magnet machine. The analysis has been undertaken in a general manner for any pair of phases in operation with the remaining phases inactive. The compensation technique determines the required alternating currents in the machine to eliminate the second-harmonic DC-link current, while at the same time minimising the total rms current in the windings. An additional benefit of the compensation technique is a reduction in the magnitude of the electromagnetic torque ripple. Practical results are included from a 70 kW, five-phase generator system to validate the analysis and illustrate the performance of the compensation technique.

Disturbance rejection by acceleration feedforward: Application to dynamic positioning

AbstractThis paper addresses environmental disturbance rejection in dynamic systems by means of acceleration feedforward. A feedforward structure calculates the environmental force and magnitude by comparing the filtered acceleration measurement with the acceleration due to actuation and known forces. Direct compensation of the environment by feedforward will alleviate the position and velocity feedback terms. The presented scheme compensates environmental disturbances affecting the system in addition to model uncertainties. First, the design is used for a mechanical system and illustrated for an inverted pendulum. Then, the main application, being a dynamic positioning system affected by ice forces in an Arctic operation, is controlled by acceleration feedforward to give enhanced performance.

Active Vibration Control of Roll Press System by Piezoelectric Actuators

AbstractA common treatment in manufacturing web‐like thin materials like paper is to manipulate it between two cylinders under rolling contact. A roll press is sensitive to vibration, which is unwanted, because it marks the web by regular stripes. A piezoelectric actuator is an excellent device for vibration control applications because of its large force generation, very short response time and easy controllability. Control of piezoelectric actuator is straightforward by direct compensation of input voltage. (© 2010 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)

THE EXPOSITION COLONIALE OF 1900

In recent years there has been an academic focus on the exhibition of the French comptoirs (trading posts) in India at the Expositions coloniales (Colonial Exhibitions) of the nineteenth and twentieth centuries by scholars such as Catherine Servan-Schreiber (2002). This essay builds upon such works, and uses the French colonial exhibition of 1900 as an exemplar of the exhibitions between 1870 and 1931 to consider how France's loss of India in 1763 acted as a preface to the period of colonial expansion that followed the Franco-Prussian War. Furthermore, it demonstrates how the failure of the ancien régime colonial venture in India was apparent in the representations of both the French trading posts in India – namely, Pondichéry, Chandernagor, Karikal, Yanaon and Mahé – and French Indochina alike, and explores how the creation of this colony was significantly displayed by the exhibition as a direct compensation for what Claude Farrère dubbed in 1935 ‘l'Inde perdue’ [lost India]. Finally, through the analysis of the mythologized accounts of the French colonial venture on the subcontinent, this essay highlights how this lost and essentially imaginary empire was used as a metaphorical battleground to conduct comparisons with the colonies of France's ‘frère ennemi’ [a brother who is also an enemy], the British.

Hilfsmittel zum Behinderungsausgleich: Rechtlicher Rahmen und Reformbedarf

The supply with rehabilitative technical aids in Germany is regulated in a complex way. Technical aids can be granted by different social security agencies for purposes of medical treatment, for long term care, for compensation of disabilities in the context of medical rehabilitation, for workplace participation and for participation in society. At present, the most relevant carriers of technical aids for compensation of disabilities are the statutory health insurance funds. In practice and jurisprudence there are several problems. A distinction is made between direct and indirect compensation of disability, and the obligation to provide cover is restricted to the compensation of basic needs. Both are questionable in the light of the German disability law and the ICF. The needs assessment cannot be carried out by physicians alone but has to be multifactorial. Fixed prices for technical aids are not always sufficient. In that case they are unlawful according to the latest jurisprudence of the Federal Social Court. The technical aids register of the statutory health insurance funds cannot restrict the rights of the insured. Further problems of legislation and practice are the responsibility for the supply with technical aids in homes for elderly or disabled persons and the tendering procedures of the statutory health insurance funds. A new codification is needed to simplify and clarify the law.

Direct Load Control (DLC) Considering Nodal Interrupted Energy Assessment Rate (NIEAR) in Restructured Power Systems

A direct load control (DLC) scheme of air conditioning loads (ACL) considering direct monetary compensation to ACL customers for the service interruption caused by the DLC program is proposed in this paper for restructured power systems. The nodal interrupted energy assessment rate (NIEAR), which is used as the bids from the ACL customers, is utilized to determine the direct monetary compensation to the ACL customers. The proposed scheme was investigated for the PoolCo electricity market. The optimal DLC scheme is determined based on the minimum system operating cost which is comprised of the system energy cost, the system spinning reserve cost and the compensation cost to the ACL customers. Dynamic programming (DP) was used to obtain the optimal DLC scheme. The IEEE reliability test system (RTS) was studied to illustrate the proposed DLC scheme.

Improved parameter estimation by noise compensation in the time-scale domain

It was shown recently that parameter estimation can be performed directly in the time-scale domain by isolating regions wherein the prediction error can be attributed to the error of individual dynamic model parameters [1]. Based on these single-parameter equations of the prediction error, individual model parameters error can be estimated for iterative parameter estimation. An added benefit of this parameter estimation method, besides its unique convergence characteristics, is the added capacity for direct noise compensation in the time-scale domain. This paper explores this benefit by introducing a noise compensation method that estimates the distortion by noise of the prediction error in the time-scale domain and incorporates that as a confidence factor to bias the estimation of individual parameters error. This method is shown to improve the precision of the estimated parameters when the confidence factors accurately represent the noise distortion of the prediction error.