Evaluation of control devices for asphalt pavement recycling operations : summary report for research project HR-188, 1982

The objective of the research project was to seek acceptable solutions to the air pollution problem created in the asphalt recycling process using modified conventional equipment.

A survey of control architectures for autonomous mobile robots

MEDEIROS, Adelardo A. D.A survey of control architectures for autonomous mobile robots. J. Braz. Comp. Soc., Campinas, v. 4, n. 3, abr. 1998 .Disponível em: Acesso: 27 set. 2010.

Optimal Controller Designs for Rotating Machines - Penalising the Rate of Change of Control Forcing

In the context of active control of rotating machines, standard optimal controller methods enable a trade-off to be made between (weighted) mean-square vibrations and (weighted) mean-square currents injected into magnetic bearings. One shortcoming of such controllers is that no concern is devoted to the voltages required. In practice, the voltage available imposes a strict limitation on the maximum possible rate of change of control force (force slew rate). This paper removes the aforementioned existing shortcomings of traditional optimal control.

Locus of Control revisited: development of a new bi-dimensional measure

Locus of control (LOC) has a long tradition in Psychology, and various instruments have been designed for its measurement. However, the dimensionality of the construct is unclear, and still gives rise to considerable controversy. The aim of the present work is to present new evidence of validity in relation to the dimensionality of LOC. To this end, we developed a new measurement instrument with 23 items. The sample was made up of 697 Spanish participants, of whom 57.5% were women (M=22.43; SD= 9.19). The results support the bi-dimensionality of LOC: internal (α=.87) and external (α=.85). Furthermore, both subscales have shown adequate validity evidence in relation to self-efficacy, achievement motivation and optimism (r xy> .21). Statistically significant differences were found by sex (p < .05): men scored higher in external LOC and women in internal LOC. The validity evidence supports a two-dimensional structure for the LOC, and the measurement instrument developed showed adequate psychometric properties.

Development and Verification of Control and Protection Strategies in Hybrid AC/DC Power Systems for Smart Grid Applications

Modern power networks incorporate communications and information technology infrastructure into the electrical power system to create a smart grid in terms of control and operation. The smart grid enables real-time communication and control between consumers and utility companies allowing suppliers to optimize energy usage based on price preference and system technical issues. The smart grid design aims to provide overall power system monitoring, create protection and control strategies to maintain system performance, stability and security. This dissertation contributed to the development of a unique and novel smart grid test-bed laboratory with integrated monitoring, protection and control systems. This test-bed was used as a platform to test the smart grid operational ideas developed here. The implementation of this system in the real-time software creates an environment for studying, implementing and verifying novel control and protection schemes developed in this dissertation. Phasor measurement techniques were developed using the available Data Acquisition (DAQ) devices in order to monitor all points in the power system in real time. This provides a practical view of system parameter changes, system abnormal conditions and its stability and security information system. These developments provide valuable measurements for technical power system operators in the energy control centers. Phasor Measurement technology is an excellent solution for improving system planning, operation and energy trading in addition to enabling advanced applications in Wide Area Monitoring, Protection and Control (WAMPAC). Moreover, a virtual protection system was developed and implemented in the smart grid laboratory with integrated functionality for wide area applications. Experiments and procedures were developed in the system in order to detect the system abnormal conditions and apply proper remedies to heal the system. A design for DC microgrid was developed to integrate it to the AC system with appropriate control capability. This system represents realistic hybrid AC/DC microgrids connectivity to the AC side to study the use of such architecture in system operation to help remedy system abnormal conditions. In addition, this dissertation explored the challenges and feasibility of the implementation of real-time system analysis features in order to monitor the system security and stability measures. These indices are measured experimentally during the operation of the developed hybrid AC/DC microgrids. Furthermore, a real-time optimal power flow system was implemented to optimally manage the power sharing between AC generators and DC side resources. A study relating to real-time energy management algorithm in hybrid microgrids was performed to evaluate the effects of using energy storage resources and their use in mitigating heavy load impacts on system stability and operational security.

Social-cognitive Antecedents of Ambidextrous Orientation in Family-owned Startups: The Role of Family Ties, Achievement Motivation, and Internal Locus of Control

Regulatory Focus Theory predicts that the motivation to self-regulate goal-directed thought and behavior depends on two distinct regulation strategies: a promotion focus based on attaining gains and a prevention focus based on avoiding losses. This study took a social-cognitive approach predicting that regulatory focus has an impact on how family startups (several family related founders) explore “new ideas”, exploit “old certainties” and achieve the balance of both (ambidexterity), compared to lone founder startups (only one founder present). It was proposed that the social context of family ties among founders leads them to a prevention focus concerned with avoiding the loss of the socio-emotional benefits of those ties. In order to avoid such a loss, family founders were expected to increase their risk perceptions and thus, explore less than lone founders, who lack such socio-emotional ties. It was also proposed that two commonly used psychological traits in entrepreneurship research --achievement motivation and internal locus of control, predispose entrepreneurs to a promotion focus. Founders with a promotion focus, in turn, were hypothesized to lead startups to more risk-seeking behaviors and to more explorative orientation. The previous argument was used as a springboard to derive hypotheses about ambidexterity (the ability to exploit and explore simultaneously) and survival hazards. Using Regulatory Focus Theory, exploitative orientation, conceptualized as the motivational strength to continue on previous paths of action, was hypothesized to be not significantly different from that of lone founder startups. Taking previous arguments together, lone founder startups were hypothesized to be more ambidextrous than family startups. Finally, ambidexterity and internal locus of control were hypothesized to reduce survival hazards in family startups. The findings suggested that family startups explore less than lone founder startups even after controlling for group effects. Interesting but contradictory findings revealed that internal locus of control have both a positive direct effect and a positive interaction that increases the explorative and ambidextrous orientation gap of family startups over lone founder startups. As expected, ambidexterity and internal locus of control reduced survival hazards on family startups. Implications for practitioners were derived based on a sample of 470 nascent entrepreneurs.

Diageo's 'Stop Out of Control Drinking' campaign in Ireland: an analysis

Background: It has been argued that the alcohol industry uses corporate social responsibility activities to influence policy and undermine public health, and that every opportunity should be taken to scrutinise such activities. This study analyses a controversial Diageo-funded ‘responsible drinking’ campaign (“Stop out of Control Drinking”, or SOOCD) in Ireland. The study aims to identify how the campaign and its advisory board members frame and define (i) alcohol-related harms, and their causes, and (ii) possible solutions. Methods: Documentary analysis of SOOCD campaign material. This includes newspaper articles (n = 9), media interviews (n = 11), Facebook posts (n = 92), and Tweets (n = 340) produced by the campaign and by board members. All material was coded inductively, and a thematic analysis undertaken, with codes aggregated into sub-themes. Results: The SOOCD campaign utilises vague or self-defined concepts of ‘out of control’ and ‘moderate’ drinking, tending to present alcohol problems as behavioural rather than health issues. These are also unquantified with respect to actual drinking levels. It emphasises alcohol-related antisocial behaviour among young people, particularly young women. In discussing solutions to alcohol-related problems, it focuses on public opinion rather than on scientific evidence, and on educational approaches and information provision, misrepresenting these as effective. “Moderate drinking” is presented as a behavioural issue (“negative drinking behaviours”), rather than as a health issue. Conclusions: The ‘Stop Out of Control Drinking’ campaign frames alcohol problems and solutions in ways unfavourable to public health, and closely reflects other Diageo Corporate Social Responsibility (CSR) activity, as well as alcohol and tobacco industry strategies more generally. This framing, and in particular the framing of alcohol harms as a behavioural issue, with the implication that consumption should be guided only by self-defined limits, may not have been recognised by all board members. It suggests a need for awareness-raising efforts among the public, third sector and policymakers about alcohol industry strategies

Welke 'acteur' neemt de controllerrol als extraverte business partner?

Which 'actor' takes the management accountant role as an extravert business partner? Does a relation between the personal trait Extraversion and fulfilling a management accountant role as a business partner exist? Open Universiteit Nederland End thesis MSc Management, Accounting & Finance Support 1: Prof. dr. A.C.N. van de Ven RA Support 2: dr. P.C.M. Claes Examinator: dr. P. Kamminga Date of approval: September 3, 2014 student: P.R. van der Wal (studentnumber 839104017 email petervanderwal2003@yahoo.com The main question of this research is: Does a relation between the personal trait Extraversion and fulfilling a management accountant role as a business partner exist? This research is based on the dataset obtained by the controller survey 2013, executed in commission of the 'Open Universiteit' (Bork & van der Wal, 2014). From the literature review it is clear: among other management accountant roles we need business partners. And there is a relation between the personal trait Extraversion and fulfilling the role as business partner. At the same time a lack of necessary personal traits for this role has been noticed, among which is Extraversion. The factor- and cluster analyses reported by Bork & van der Wal (2014) resulted in the identification of two types of management accountant roles. In this extended research TYPE II is identified as a business partner because (s)he practices activity-combinations which are related to strategy, analyzing, supporting management in decision making, advisory, change-agency and representing the organization. 36% of the population of Dutch management accountants with a master degree (or similar) meet with the role of the business partner. Although the fulfillment of the role (TYPE II) is not purely business partnering. E.g. reporting and scorekeeping are still activities executed by TYPE II and it is not clear to what extent. Apart from that, role TYPE I executes change management and risk-management activities, which are (according to the definition) activities that belong to the business partner. The role as business partner is practiced but not that optimal as defined in theory. The logistic regression analyses on the survey-data show that Extraversion among three other triggers is significant for the prediction of the fulfillment of the management accountant role (Bork & van der Wal, 2014). A more extravert personal trait predicts a preference for TYPE II, which relates to the business partner. This 'in depth research' concentrated on the relation between the Big Five personal traits and the six activity-combinations (factors) instead of on the two clusters (I and II). The statistic analyses confirm the predicting influence of Extraversion on the business partner role. Although, except for one factor, no extra significance has been found in this additional research. The essential question can be confirmed positively: the management accountant role business partner exists in practice, some management accountants are more extravert then others, and there is a positive relation between extraversion and fulfilling the business partner role. Some formulated research limitations are related to the statistical weakness of some prediction outcomes and to interpretation differences that might occur. Further research can e.g. concentrate on the other personal traits and the significance for role-differentiation in education programs. The management accountant survey 2013 Management accountant roles in 2013 in the Netherlands Open Universiteit Nederland End thesis MSc Management, Accounting & Finance Support 1: Prof. dr. A.C.N. van de Ven RA Support 2: dr. P.C.M. Claes Examinator: dr. P. Kamminga Date of approval: September 3, 2014 student: P.R. van der Wal and H.J. Bork studentnumber: 839104017 and 838532340) email: petervanderwal2003@yahoo.com and hjbork@hotmail.com This paper describes the conceptual model and results of the 'management accountants survey 2013'. The survey is part of a longitudinal survey, earlier executed in 2004, 2007 and 2010 under responsibility of the 'Open Universiteit Nederland'. Secondly the dataset of this survey will be used by us to do our own analyses on the predicting value of the triggers 'personality factor: extraversion' and 'lever of control: interactive controls' on the management accounting role that comes close to a role defined as 'Business Partner'. Scientific research shows that there are different management accounting roles, and that these roles change and that preferences exist for certain roles (Verstegen B. , Loo, Mol, Slagter, & Geerkens, 2007). The main question that will be answered in this paper is which coherent combinations of activities are being executed by management accountants in 2013 in the Netherlands by master-graduates? And secondly which triggers of management accountants' activities predict to which cluster a management accountant belongs? The conceptual model of this research has been developed in 2004 (Verstegen B. , Loo, Mol, Slagter, & Geerkens, 2007). For this research the same 37 activities as in the former researches are included (appendix 1). In the trigger-set (appendix 1) some adaptations have been made for reasons of restricting the length of the survey and to pinpoint on particular research goals (e.g. personality and levers of control). The coherent combinations of activities were found by a factor-analysis and the groups of controllers by a cluster analysis. A regression analysis shows which trigger-items are most significant. The survey has been sent to 2.353 students that finished a controller-study on a Dutch University. There was a 9% (211) response with a completely filled survey. 137 of which indicated to work in a controller-function at the moment. These controllers have been included in the results. The factor-analysis results in six different coherent combinations of activities (factors). Shortly these factors are: advising top management on strategic level with result-effecting information (1), organizing internal reporting (2) organizing and representing the organization on external reporting (3), advising and managing changes by shortcomings in processes and control systems (4), maintaining and managing administrative organization- , information- and control systems (5) and organizing/executing risk management and internal audit (6). Factors 4, 5 and 6 are clustered in cluster TYPE I (125 controllers) and factors 1, 2 and 3 in cluster TYPE II (69 controllers). TYPE II can be associated with the management accountant role 'Business Partner', although the accountant keeps partly active in a scorekeeper role. The four most significant triggers for predicting being a TYPE II controller are 'Executing a risk-management task in order to meet compliance standards' (1), extraversion (2), company size in terms of fte (3) and gender (4).

Delay distribution based robust H∞ control of networked control systems with uncertainties

Network induced delay in networked control systems (NCS) is inherently non-uniformly distributed and behaves with multifractal nature. However, such network characteristics have not been well considered in NCS analysis and synthesis. Making use of the information of the statistical distribution of NCS network induced delay, a delay distribution based stochastic model is adopted to link Quality-of-Control and network Quality-of-Service for NCS with uncertainties. From this model together with a tighter bounding technology for cross terms, H∞ NCS analysis is carried out with significantly improved stability results. Furthermore, a memoryless H∞ controller is designed to stabilize the NCS and to achieve the prescribed disturbance attenuation level. Numerical examples are given to demonstrate the effectiveness of the proposed method.

Output feedback control of discrete-time systems in networked environments

This correspondence paper addresses the problem of output feedback stabilization of control systems in networked environments with quality-of-service (QoS) constraints. The problem is investigated in discrete-time state space using Lyapunov’s stability theory and the linear inequality matrix technique. A new discrete-time modeling approach is developed to describe a networked control system (NCS) with parameter uncertainties and nonideal network QoS. It integrates a network-induced delay, packet dropout, and other network behaviors into a unified framework. With this modeling, an improved stability condition, which is dependent on the lower and upper bounds of the equivalent network-induced delay, is established for the NCS with norm-bounded parameter uncertainties. It is further extended for the output feedback stabilization of the NCS with nonideal QoS. Numerical examples are given to demonstrate the main results of the theoretical development.

Efficient control of an autonomous underwater vehicle while accounting for thruster failure

This paper is concerned with the design and implementation of control strategies onto a test-bed vehicle with six degrees-of-freedom. We design our trajectories to be efficient in time and in power consumption. Moreover, we also consider cases when actuator failure can arise and discuss alternate control strategies in this situation. Our calculations are supplemented by experimental results.

A first extension of geometric control theory to underwater vehicles

This paper serves as a first study on the implementation of control strategies developed using a kinematic reduction onto test bed autonomous underwater vehicles (AUVs). The equations of motion are presented in the framework of differential geometry, including external dissipative forces, as a forced affine connection control system. We show that the hydrodynamic drag forces can be included in the affine connection, resulting in an affine connection control system. The definitions of kinematic reduction and decoupling vector field are thus extended from the ideal fluid scenario. Control strategies are computed using this new extension and are reformulated for implementation onto a test-bed AUV. We compare these geometrically computed controls to time and energy optimal controls for the same trajectory which are computed using a previously developed algorithm. Through this comparison we are able to validate our theoretical results based on the experiments conducted using the time and energy efficient strategies.

Modelling and performance evaluation of the IEEE 802.11 DCF for real-time control

Popular wireless networks, such as IEEE 802.11/15/16, are not designed for real-time applications. Thus, supporting real-time quality of service (QoS) in wireless real-time control is challenging. This paper adopts the widely used IEEE 802.11, with the focus on its distributed coordination function (DCF), for soft-real-time control systems. The concept of the critical real-time traffic condition is introduced to characterize the marginal satisfaction of real-time requirements. Then, mathematical models are developed to describe the dynamics of DCF based real-time control networks with periodic traffic, a unique feature of control systems. Performance indices such as throughput and packet delay are evaluated using the developed models, particularly under the critical real-time traffic condition. Finally, the proposed modelling is applied to traffic rate control for cross-layer networked control system design.

Universal active and reactive power control of electronically interfaced distributed generation sources in virtual power plants operating in gridconnected and islanding modes

The control paradigms of the distributed generation (DG) sources in the smart grid are realised by either utilising virtual power plant (VPP) or by employing MicroGrid structures. Both VPP and MicroGrid are presented with the problem of control of power flow between their comprising DG sources. This study depicts this issue for VPP and proposes a novel and improved universal active and reactive power flow controllers for three-phase pulse width modulated voltage source inverters (PWM-VSI) operating in the VPP environment. The proposed controller takes into account all cases of R-X relationship, thus allowing it to function in systems operating at high, medium (MV) and low-voltage (LV) levels. Also proposed control scheme for the first time in an inverter control takes into account the capacitance of the transmission line which is an important factor to accurately represent medium length transmission lines. This allows the proposed control scheme to be applied in VPP structures, where DG sources can operate at MV LV levels over a short/medium length transmission line. The authors also conducted small signal stability analysis of the proposed controller and compared it against the small signal study of the existing controllers.