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Article
Publication date: 13 June 2020

José Francisco Villarreal Valderrama, Luis Takano, Eduardo Liceaga-Castro, Diana Hernandez-Alcantara, Patricia Del Carmen Zambrano-Robledo and Luis Amezquita-Brooks

Aircraft pitch control is fundamental for the performance of micro aerial vehicles (MAVs). The purpose of this paper is to establish a simple experimental procedure to…

Abstract

Purpose

Aircraft pitch control is fundamental for the performance of micro aerial vehicles (MAVs). The purpose of this paper is to establish a simple experimental procedure to calibrate pitch instrumentation and classical control algorithms. This includes developing an efficient pitch angle observer with optimal estimation and evaluating controllers under uncertainty and external disturbances.

Design/methodology/approach

A wind tunnel test bench is designed to simulate fixed-wing aircraft dynamics. Key elements of the instrumentation commonly found in MAVs are characterized in a gyroscopic test bench. A data fusion algorithm is calibrated to match the gyroscopic test bench measurements and is then integrated into the autopilot platform. The elevator-angle to pitch-angle dynamic model is obtained experimentally. Two different control algorithms, based on model-free and model-based approaches, are designed. These controllers are analyzed in terms of parametric uncertainties due to wind speed variations and external perturbation because of sudden weight distribution changes. A series of experimental tests is performed in wind-tunnel facilities to highlight the main features of each control approach.

Findings

With regard to the instrumentation algorithms, a simple experimental methodology for the design of optimal pitch angle observer is presented and validated experimentally. In the context of the platform design and identification, the similitude among the theoretical and experimental responses shows that the platform is suitable for typical pitch control assessment. The wind tunnel experiments show that a fixed linear controller, designed using classical frequency domain concepts, is able to provide adequate responses in scenarios that approximate the operation of MAVs.

Research limitations/implications

The aircraft orientation observer can be used for both pitch and roll angles. However, for simultaneousyaw angle estimation the proposed design method requires further research. The model analysis considers a wind speed range of 6-18 m/s, with a nominal operation of 12 m/s. The maximum experimentally tested reference for the pitch angle controller was 20°. Further operating conditions may require more complex control approaches (e.g. scheduling, non-linear, etc.). However, this operating range is enough for typical MAV missions.

Originality/value

The study shows the design of an effective pitch angle observer, based on a simple experimental approach, which achieved locally optimum estimates at the test conditions. Additionally, the instrumentation and design of a test bench for typical pitch control assessment in wind tunnel facilities is presented. Finally, the study presents the development of a simple controller that provides adequate responses in scenarios that approximate the operation of MAVs, including perturbations that resemble package delivery and parametric uncertainty due to wind speed variations.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 7
Type: Research Article
ISSN: 1748-8842

Keywords

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Book part
Publication date: 17 March 2010

Diana Hernández

Many studies on legal consciousness suggest that the poor and working class are fundamentally excluded or disadvantaged, having a different legal consciousness from others…

Abstract

Many studies on legal consciousness suggest that the poor and working class are fundamentally excluded or disadvantaged, having a different legal consciousness from others that is “against the law” or cynical and dismissive about the law. My study is the first to examine polyvocality and change in legal consciousness among the poor. The women in my study are disadvantaged, to be sure, and face barriers to learning and mastering the law. But the interviews conducted for this study revealed that a remarkable shift in legal consciousness could take place as a result of the interface of perceptions, experience, and interaction with legal services, courts, and other members of the community. In this chapter, I develop a theoretical framework of legal entitlement in order to provide a more nuanced understanding of the variations and changes in legal consciousness among low-income mothers as well as how these differences impact the ways in which marginalized group members come to develop and exercise legal consciousness and also to mobilize the law.

Details

Special Issue Interdisciplinary Legal Studies: The Next Generation
Type: Book
ISBN: 978-1-84950-751-6

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Book part
Publication date: 17 March 2010

Abstract

Details

Special Issue Interdisciplinary Legal Studies: The Next Generation
Type: Book
ISBN: 978-1-84950-751-6

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Article
Publication date: 1 July 2004

April Linton

Observes that, in some public schools in the USA, dual language instead of English only is being promoted as a plus and not the drawback it was once seen to be. Stresses…

Abstract

Observes that, in some public schools in the USA, dual language instead of English only is being promoted as a plus and not the drawback it was once seen to be. Stresses there is still opposition to dual language or other languages being used in the US. Reckons that educated parents are the likeliest to seek dual‐language education for their children. Uses tables and figures to show the dual language options and variances. Concludes that there is potential for two‐way immersion to expand.

Details

International Journal of Sociology and Social Policy, vol. 24 no. 7/8
Type: Research Article
ISSN: 0144-333X

Keywords

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Book part
Publication date: 5 May 2017

Bartosz Sawik, Javier Faulin and Elena Pérez-Bernabeu

The purpose of this chapter is to solve multi-objective formulation for traveling salesman and transportation problems. Computations are based on real data for the road…

Abstract

The purpose of this chapter is to solve multi-objective formulation for traveling salesman and transportation problems. Computations are based on real data for the road freight transportation of a Spanish company. The company was selected because of its importance in Spanish economy and market. This company is important in the whole country; however, it has its higher importance in the northern part of Spain. The requirements for these models are the minimization of total distance and the CO2 emissions. To achieve this, it is required to know and carry out the minimization of the total distance traveled by the trucks during the deliveries. The deliveries are going to be executed between the different locations, nodes, in the region, and Elorrio, where the depot is situated. The data have been used to decide the best route in order to obtain a minimization of cost for the company. As it was mentioned earlier, the problems are focused on the reduction of the amount of CO2 emissions and minimization of total distance; by studying different parameters, the best solutions of route transportation have been obtained. The software used to solve these models is CPLEX solver with AMPL programming language.

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Book part
Publication date: 11 November 2016

Neda Moinolmolki, Juana Gaviria-Loaiza and Myae Han

Nowadays children from immigrant families are the fastest growing group of youth in the United States. Despite the fact that emerging research has highlighted the…

Abstract

Nowadays children from immigrant families are the fastest growing group of youth in the United States. Despite the fact that emerging research has highlighted the significance of strong partnerships between families and high-quality early childcare/education programs, many immigrant families face numerous barriers in accessing high-quality childcare/early education as well as establishing strong partnerships with centers. The purpose of this chapter is to explore the emerging challenges that immigrant families face in navigating the U.S. early childhood education system. This chapter first briefly reviews the literature on the role of family involvement in early childhood education within the general U.S. population. This is followed by a review of the unique funds of knowledge that immigrant parents engage in while interacting with their children at home. Then this chapter explores the barriers of immigrant families in developing strong partnerships with early childcare/education programs such as, communication, limited parental English proficiency, lack of public funding, acculturation, education, and cultural perceptions of involvement. Furthermore, this is followed by a focus on two distinct rising immigrant populations within the United States, Hispanic (specifically non-refugee) and refugee populations, and their unique sets of obstacles. Lastly, recommendations are provided for future practitioners and policymakers to support the establishment of stronger immigrant family and professional partnerships within early education and childcare settings.

Details

Family Involvement in Early Education and Child Care
Type: Book
ISBN: 978-1-78635-408-2

Keywords

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Book part
Publication date: 27 December 2018

Carla Gonzalez, Jessica Graber, Diana Galvez and Leslie Ann Locke

In this study, the authors investigated the academic and social experiences of first-generation undergraduate Latinx students who participated in a Latinx student-focused…

Abstract

In this study, the authors investigated the academic and social experiences of first-generation undergraduate Latinx students who participated in a Latinx student-focused organization at a large, research-intensive, Predominately White Institution (PWI) in the Midwest. Our results revealed three major themes. First, participants considered the Latinx student organization to be a significant resource for their social integration into the university; however, it was less significant as an academic resource. Second, the participants recognized that while the university “tries” to promote diversity, they felt that the university could do more in promoting ethnic student groups and their interests across campus. Third, participants perceived that the university treats all Latinx students as one homogenous group, ignoring the diversity that exists between different Latinx groups. These themes suggest that efforts to make PWIs more diverse and inclusive may benefit from the formation and maintenance of minoritized ethnic student organizations. PWIs would also benefit by incorporating the diverse Latinx student perspectives into institutional diversity policy, and prioritizing higher-quality initiatives for greater visibility of Latinx student issues across campus. Moreover, programming that does not aggregate or homogenize Latinx identity, but embraces and values the multifaceted Latinx identities, would also benefit PWIs.

Details

Perspectives on Diverse Student Identities in Higher Education: International Perspectives on Equity and Inclusion
Type: Book
ISBN: 978-1-78756-053-6

Keywords

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Article
Publication date: 14 October 2019

Josefine Weigt-Rohrbeck and Mai Skjøtt Linneberg

Previous work on employee-driven innovation (EDI) has demonstrated the benefits of employees’ proactive behavior in achieving success with innovations. The purpose of this…

Abstract

Purpose

Previous work on employee-driven innovation (EDI) has demonstrated the benefits of employees’ proactive behavior in achieving success with innovations. The purpose of this paper is to employ the concept of personal initiative to investigate the underestimated role of employees’ agency in complex processes of innovation, showing the impact of personal initiative on employees’ innovation success.

Design/methodology/approach

Based on two embedded cases of environmental bottom-up innovation at a large manufacturing company, this study examines employees’ behavior in generating, championing and realizing such initiatives.

Findings

This paper provides insights into how employees succeeded, through taking initiative in generating, championing and realizing environmental initiatives despite facing high complexity, and resource constraints. Without being prompted from the top down, employees started these initiatives themselves and showed phase-specific behavior in overcoming the various challenges. Thus, self-starting behavior was found dominant in generating ideas, whereas proactive and persistent forms of behavior were found to be prevalent in championing and rolling out the initiatives.

Originality/value

Current understandings of EDI highlight the importance of developing employees’ potential capabilities and organizational-level guidance. Using an active performance perspective, this study emphasizes the importance of employees’ agency in ensuring EDI success, even when conditions are not conducive to their doing so.

Details

European Journal of Innovation Management, vol. 22 no. 5
Type: Research Article
ISSN: 1460-1060

Keywords

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Book part
Publication date: 10 August 2017

Tamar Diana Wilson

To summarize the shocks and stresses that peasants in Mexico have been subjected to since the 1940s and to examine the responses of sons of peasants working as…

Abstract

Purpose

To summarize the shocks and stresses that peasants in Mexico have been subjected to since the 1940s and to examine the responses of sons of peasants working as semi-informal beach vendors in Cabo San Lucas as to what they define as the worst problems of the peasantry in their hometowns.

Methodology/approach

This chapter offers an analysis of the responses of 32 sons of peasants interviewed on Medano Beach in Cabo San Lucas in October of 2012 partially as concerns whether they would like to be peasants themselves and as to what they define as the worst problems of the peasantry in their hometowns.

Findings

Twenty-five of the thirty-two vendors interviewed would be happy to be peasants. According to all of the vendors, the overwhelming problems facing the peasantry were primarily droughts or floods (related to climate change) and lack of government aid (related to neoliberalization).

Social implications

The peasantry in Mexico is being and has been marginalized both by a number of stresses and shocks, currently identified by some of those at risk as factors related to climate change and neoliberalization.

Details

Anthropological Considerations of Production, Exchange, Vending and Tourism
Type: Book
ISBN: 978-1-78743-194-2

Keywords

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Abstract

Details

Strategy, Power and CSR: Practices and Challenges in Organizational Management
Type: Book
ISBN: 978-1-83867-973-6

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