Parameter selection of an adaptive PI state observer for an induction motor

2013 ◽  
Vol 61 (3) ◽  
pp. 599-603 ◽  
Author(s):  
T. Białoń ◽  
A. Lewicki ◽  
M. Pasko ◽  
R. Niestrój
Keyword(s):  
Induction Motor ◽  
Angular Speed ◽  
Adaptation Mechanism ◽  
Dc Offset ◽  
Second Stage ◽  
Parameters Selection ◽  
Parameter Variations ◽  
Last Stage ◽  
The Impact ◽  
Selection Of

Abstract The paper discusses problems connected with the parameters selection of the proportional-integral observer, designed for reconstruction of magnetic fluxes and angular speed of an induction motor. The selection is performed in several stages that are focused on different criteria. The first stage consists in selecting observer’s gains and provides desired dynamical properties, taking into consideration immunity to disturbances and parameter variations of observed system. The second stage prevents an observer from DC-offset cumulation and instability. The last stage consists in setting the parameters of a speed adaptation mechanism. The impact of different settings on the properties of an observer is illustrated with experimental results, obtained in the multiscalar control system of an induction motor

Studies of the Modelling Accuracy of Steam Turbine Control Systems for Diagnostic Tests of Automatic Synchronizers

2013 ◽  
Vol 199 ◽  
pp. 61-66
Author(s):  
Grzegorz Redlarski ◽  
Janusz Piechocki ◽  
Mariusz Dąbkowski
Keyword(s):  
Angular Velocity ◽  
Control Systems ◽  
Working Conditions ◽  
Synchronous Generator ◽  
Angular Speed ◽  
Velocity Control ◽  
Reliable Operation ◽  
Relevant Field ◽  
The Impact ◽  
Selection Of

One of the important factors that affect the reliable operation of the power system and the rapid restitution after disaster is a quick and effective combining synchronous electric power facilities to operate in parallel [. Hence, diagnostics of automatic synchronizers at every stage of their life, from building a prototype, through the whole life, until removing such devices from the operation, is an extremely important and responsible activity. In ordinary practice, this action is performed by dedicated test of mechatronics systems, called simulators [2, , in close to real - or even more restricted - conditions. One of the major limitations in the relevant field undoubtedly concerns the selection of an appropriate structure and implementation of models of the angular velocity control systems involved in the process of connection. These models must be simple enough to allow computation with a frequency of kHz, and, at the same time, developed enough to be able to form diverse and close to real working conditions. For these reasons, classical approach is not possible, allowing the use of well-known Parks model [ of the synchronous generator and the complex - and often nonlinear [. Hence, considered above-mentioned requirements and indicated constraints, to test the automatic synchronizer the designers of mechatronics systems use a number of simplifications during modeling of the angular speed control systems [. However, models are not detailed enough to study the impact of changes in the shape of relevant characteristics under the influence of changes the angle of phase discrepancy in the process of connecting. Hence, this paper presents the results of the research of the currently used method of modeling the most commonly used control systems of angular velocity, in the respective systems.

scholarly journals THE IMPACT OF COLLECTIVE INVESTMENT SCHEMES ON FINANCIAL INCLUSION IN KENYA

2016 ◽  
Vol 1 (1) ◽  
pp. 54-73
Author(s):  
Peninah Kimani ◽  
Dr. Sifunjo Kisaka
Keyword(s):  
Social Economic ◽  
Target Population ◽  
Financial Inclusion ◽  
Survey Study ◽  
Qualitative And Quantitative ◽  
Second Stage ◽  
Financial Products ◽  
Descriptive Survey ◽  
The Impact ◽  
Selection Of

Purpose: The purpose of this study was to determine the impact of collective investment schemes in financial inclusion in Kenya.Methodology: The research design was descriptive survey study in nature since it focused on all collective investment schemes in Kenya. The target population was collective investment schemes. A sample of 11 collective schemes was selected using random sampling. The second stage of sampling involved the selection of the respondents using a stratified sampling approach. The strata were the various respondents in the schemes. Both qualitative and quantitative data was collected using a questionnaire that consisted of both open ended and close ended questions. Data was analysed using Statistical Package for Social Sciences (SPSS) and results presented in frequency tables to show how the responses for the various questions posed to the respondents. The data was then analysed in terms of descriptive statistics like frequencies, means and percentages.Results: The findings implied The study concludes that there was low access to financial products in the investment schemes. It is also possible to conclude that the there were several factors that affect financial inclusion in Kenya. These factors include age of the investor, gender, level of education and level of income.Unique contribution to theory, practice and policy: The study recommended that measures such as target marketing the segments with low access to collective investments and increasing the market budget to investors on financial matters, may be adopted. Such measures would ensure gendered financial inclusion, and inclusion of social economic classes characterized by age, level of income, education and rural urban classes.

Recent Developments Regarding Costs Awards in Constitutional and Public-interest Litigation

2019 ◽  
Vol 34 (2) ◽  
Author(s):  
Tumo Charles Maloka
Keyword(s):  
Public Interest ◽  
General Rule ◽  
Case Law ◽  
Professional Standards ◽  
Constitutional Rights ◽  
Public Interest Litigation ◽  
Second Stage ◽  
Recent Developments ◽  
Last Stage ◽  
The Impact

This contribution examines the contours of costs jurisprudence since the foundational trilogy of Ferreira v Levin NO 1996 (2) SA (CC), Affordable Medicines Trust v Minister of Health 2006 (3) SA 247 (CC) and Biowatch Trust v Registrar Genetic Resources 2009 (6) SA 232 (CC). Given that the general rule is not to award costs against unsuccessful litigants when they are litigating against state parties, the first stage of enquiry asks whether the case raises a public interest matter of transcendental importance. The second stage of enquiry delves into the impact that adverse costs orders might have on litigants seeking to vindicate constitutional rights. The last stage of enquiry considers the knotty question concerning personal costs awards against public officer-holders for conduct at variance with the Constitution. The signposts that emerge from evolving case law is that if an unsuccessful party lowered its ethical and professional standards in pursuit of a constitutional cause, such party may be mulcted with costs.  It is trite that courts will not hesitate to exercise discretion to impose adverse costs, and specifically hold public representatives personally liable for costs in order to reinforce the constitutional tri-norms of accountability, responsiveness and openness.

scholarly journals Factors Determining the Efficiency of Slovak Public Procurement

2019 ◽  
Vol 12 (1) ◽  
pp. 43-68 ◽  
Author(s):  
Matus Grega ◽  
Marta Orviska ◽  
Juraj Nemec ◽  
Colin Lawson
Keyword(s):  
Public Procurement ◽  
Government Officials ◽  
Face To Face ◽  
Second Stage ◽  
The Core ◽  
Three Stages ◽  
Last Stage ◽  
Main Factors ◽  
The Impact ◽  
Depth Interviews

AbstractMany studies analyse factors (such as corruption, competitiveness, transaction costs), which are influencing public procurement efficiency. The purpose of this paper is to find out, what the main factors are in Slovakia that are influencing public procurement efficiency, and based on our analysis, we will also estimate what is the impact of each factor on the efficiency of public procurement in Slovakia.The research for this paper was executed in three stages. We began with a small number of face-to-face in-depth interviews with specialist procurement advisors to contracting authorities. In the second stage, we created draft questionnaires for contracting authorities and for suppliers, and once we tested questionnaires, it was sent to 13,571 suppliers and to 4,300 contracting authorities. In the last stage, we used various types of analyses to examine identified factors.There is significant agreement between suppliers and contractors that the two main factors causing inefficiencies are excessive bureaucracy and corruption or other ethical shortcomings. It is shown that insufficient competition, and the excessive use of the lowest price criterion for selecting winning bids, add further inefficiencies. Savings are greatest when there are between 6 and 8 bidders. E-auctions generally produce larger savings than more traditional methods, but Slovak procurement procedures are costly, compared to most other EU states.This paper contributes to the understanding of what are the core factors which may influence public procurement efficiency. It also provides valuable information for government officials on how to change public procurement rules in order to achieve higher efficiency.

Methods for Restricting Maximum Exposure Rate in Computerized Adaptative Testing

Methodology ◽  
2007 ◽  
Vol 3 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Juan Ramon Barrada ◽  
Julio Olea ◽  
Vicente Ponsoda
Keyword(s):  
Measurement Accuracy ◽  
Computerized Adaptive Testing ◽  
Computation Time ◽  
Adaptive Testing ◽  
Exposure Rate ◽  
Control Parameters ◽  
The Impact ◽  
Two Alternatives ◽  
Selection Of ◽  
Maximum Exposure

Abstract. The Sympson-Hetter (1985) method provides a means of controlling maximum exposure rate of items in Computerized Adaptive Testing. Through a series of simulations, control parameters are set that mark the probability of administration of an item on being selected. This method presents two main problems: it requires a long computation time for calculating the parameters and the maximum exposure rate is slightly above the fixed limit. Van der Linden (2003) presented two alternatives which appear to solve both of the problems. The impact of these methods in the measurement accuracy has not been tested yet. We show how these methods over-restrict the exposure of some highly discriminating items and, thus, the accuracy is decreased. It also shown that, when the desired maximum exposure rate is near the minimum possible value, these methods offer an empirical maximum exposure rate clearly above the goal. A new method, based on the initial estimation of the probability of administration and the probability of selection of the items with the restricted method ( Revuelta & Ponsoda, 1998 ), is presented in this paper. It can be used with the Sympson-Hetter method and with the two van der Linden's methods. This option, when used with Sympson-Hetter, speeds the convergence of the control parameters without decreasing the accuracy.

Impact of removing ESBL designation from culture reports on the selection of antibiotics for the treatment of infections associated with ESBL-producing organisms

2020 ◽  
Vol 41 (5) ◽  
pp. 604-607 ◽  
Author(s):  
Mark D. Lesher ◽  
Cory M. Hale ◽  
Dona S. S. Wijetunge ◽  
Matt R. England ◽  
Debra S. Myers ◽  
...  
Keyword(s):  
Antimicrobial Stewardship ◽  
Antibiotic Prescribing ◽  
The Impact ◽  
Inhibitor Combination ◽  
Lactamase Inhibitor ◽  
Selection Of

AbstractWe characterized the impact of removal of the ESBL designation from microbiology reports on inpatient antibiotic prescribing. Definitive prescribing of carbapenems decreased from 48.4% to 16.1% (P = .01) and β-lactam–β-lactamase inhibitor combination increased from 19.4% to 61.3% (P = .002). Our findings confirm the importance of collaboration between microbiology and antimicrobial stewardship programs.

scholarly journals The Impact of Alkaloid-Producing Epichloë Endophyte on Forage Ryegrass Breeding: A New Zealand Perspective

Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 158
Author(s):  
Colin Eady
Keyword(s):  
Seed Production ◽  
Health Issues ◽  
Abiotic Stressors ◽  
Livestock Health ◽  
The Right ◽  
The Impact ◽  
The Relationship ◽  
And Storage ◽  
Selection Of ◽  
Epichloë Endophyte

For 30 years, forage ryegrass breeding has known that the germplasm may contain a maternally inherited symbiotic Epichloë endophyte. These endophytes produce a suite of secondary alkaloid compounds, dependent upon strain. Many produce ergot and other alkaloids, which are associated with both insect deterrence and livestock health issues. The levels of alkaloids and other endophyte characteristics are influenced by strain, host germplasm, and environmental conditions. Some strains in the right host germplasm can confer an advantage over biotic and abiotic stressors, thus acting as a maternally inherited desirable ‘trait’. Through seed production, these mutualistic endophytes do not transmit into 100% of the crop seed and are less vigorous than the grass seed itself. This causes stability and longevity issues for seed production and storage should the ‘trait’ be desired in the germplasm. This makes understanding the precise nature of the relationship vitally important to the plant breeder. These Epichloë endophytes cannot be ‘bred’ in the conventional sense, as they are asexual. Instead, the breeder may modulate endophyte characteristics through selection of host germplasm, a sort of breeding by proxy. This article explores, from a forage seed company perspective, the issues that endophyte characteristics and breeding them by proxy have on ryegrass breeding, and outlines the methods used to assess the ‘trait’, and the application of these through the breeding, production, and deployment processes. Finally, this article investigates opportunities for enhancing the utilisation of alkaloid-producing endophytes within pastures, with a focus on balancing alkaloid levels to further enhance pest deterrence and improving livestock outcomes.

Researching American Muslims: A Case Study of Surveillance and Racialized State Control

2021 ◽  
pp. 1-16
Author(s):  
Hajer Al-Faham
Keyword(s):  
United States ◽  
Science Research ◽  
The United States ◽  
State Control ◽  
Limited Data ◽  
American Muslims ◽  
State Repression ◽  
Second Stage ◽  
Selection Of

How does surveillance shape political science research in the United States? In comparative and international politics, there is a rich literature concerning the conduct of research amid conditions of conflict and state repression. As this literature locates “the field” in distant contexts “over there,” the United States continues to be saturated with various forms of state control. What this portends for American politics research has thus far been examined by a limited selection of scholars. Expanding on their insights, I situate “the field” in the United States and examine surveillance of American Muslims, an understudied case of racialized state control. Drawing on qualitative data from a case study of sixty-nine interviews with Arab and Black American Muslims, I argue that surveillance operated as a two-stage political mechanism that mapped onto research methodologically and substantively. In the first stage, surveillance reconfigured the researcher-researchee dynamic, hindered recruitment and access, and limited data-collection. In the second stage, surveillance colored the self-perceptions, political attitudes, and civic engagement of respondents, thereby indicating a political socialization unfolding among Muslims. The implications of this study suggest that researchers can mitigate against some, but not all, of the challenges presented by surveillance and concomitant forms of state control.

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