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Article
Publication date: 21 September 2022

Yujie Zhang, Wenchao Niu and Bin Li

Structural stress and strain in the key components of aircraft structure is important for structural health monitoring and strength assessment. However, the measure of…

Abstract

Purpose

Structural stress and strain in the key components of aircraft structure is important for structural health monitoring and strength assessment. However, the measure of dynamic strain is often difficult to implement because of the complex test equipment and inconvenient measure points, especially in flight test. This study aims to propose an algorithm of dynamic strain estimation using the acceleration response in time domain to simplify the measure of dynamic strain.

Design/methodology/approach

The relationship between the strain and acceleration response is established through the sinusoidal response or modal analysis, which is insensitive to the excitation position and form. A band-pass filter is used to obtain the modal acceleration response, and a filter frequency band selection method is proposed. Then, the dynamic strain at the concerned points can be estimated based on the modal superposition principle.

Findings

Simulation and experiment are implemented to validate the applicability and effectiveness of the strain estimation method. The estimated strain results agree well with numerical simulation as well as the experimental results. The simplicity and accuracy of the strain estimation method show practicability for dynamic strength and fatigue analysis in engineering applications.

Originality/value

An algorithm of dynamic strain estimation using the acceleration response in time domain is developed. A band-pass filter is used to obtain the modal acceleration response, and a filter frequency band selection method is proposed. The dynamic strain at the concerned points can be estimated based on the modal superposition principle.

Details

Aircraft Engineering and Aerospace Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1748-8842

Keywords

Book part
Publication date: 17 September 2020

Lorenzo Skade, Sarah Stanske, Matthias Wenzel and Jochen Koch

Acceleration’, that is, the performance of activities in ever-shorter periods of time, is a distinctive feature of contemporary organizations and societies that is…

Abstract

Acceleration’, that is, the performance of activities in ever-shorter periods of time, is a distinctive feature of contemporary organizations and societies that is reflected in, and driven by startups’ attempts to scale up their businesses in ever-faster ways. Although prior research has highlighted that temporary organizing is a key way to accelerate the startup process, little is known about how actors do so. Based on a one-year ethnographic study at a startup accelerator, the authors explore how actors enact temporary organizing to attempt to accelerate the startup process. Their analysis shows that this process involves a plurality of partly conflicting temporal structures. As their study shows, such conflicts invoke tensions that actors live out in their daily activities. The authors identify three temporal practices – sequencing, freezing, and merging – through which actors engaged in temporary organizing enact acceleration in the startup process by reconciling these temporal structures. Their study has implications for understanding time in the expanding literature on temporary organizing and acceleration.

Details

Tensions and paradoxes in temporary organizing
Type: Book
ISBN: 978-1-83909-348-7

Keywords

Article
Publication date: 24 January 2022

Samin Mahdavian, Ming Lu and Estacio Pereira

Previous research regarding shaping factors and major causes behind accidents in the construction field is reviewed. In particular, a hypothetical model is established to…

Abstract

Purpose

Previous research regarding shaping factors and major causes behind accidents in the construction field is reviewed. In particular, a hypothetical model is established to correlate activity time, cost and safety in the context of construction activity acceleration planning. Two demonstration cases are presented to illustrate the proposed theoretical model in the context of critical activity expedition planning. Further, a third case uses a 100-activity project to perform the global level total project time and cost analysis, identifying specific activity acceleration plans that would materialize the shortened total project time at the lowest total project cost.

Design/methodology/approach

This research proposes a safety-centric application framework to guide construction acceleration planning at both activity and project levels while taking sufficient preventive measures against safety hazards and accidents. As planning construction acceleration by factoring in safety constraints inevitably drives up cost, it is imperative to control increases in activity costs at the local level in connection with schedule acceleration planning while at the same time not compromising on safety. This research also addresses this critical question through performing global level total project time and cost analysis.

Findings

An application framework is proposed for guiding a planner through identifying accident shaping factors, obeying schedule acceleration rules and accounting for safety-related costs in attempts to mitigate hazardous situations on-site at both activity level (local) and project level (global), resulting in (1) minimizing the increase of total project cost in schedule acceleration while at the same time not compromising on safety at individual activities; (2) producing specific execution plans on each individual activity in terms of the amount of time to crash and the associated activity cost.

Originality/value

This study is original in developing theories and methods for evaluating the impact of safety constraints upon construction time and cost in activity acceleration planning and project time-cost analysis. The research fills a gap in knowledge in terms of how to factor in sufficient safety constraints while achieving project time and cost objectives on construction acceleration planning at both activity and project levels.

Details

Engineering, Construction and Architectural Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0969-9988

Keywords

Article
Publication date: 11 February 2021

Yongxing Guo, Min Chen, Li Xiong, Xinglin Zhou and Cong Li

The purpose of this study is to present the state of the art for fiber Bragg grating (FBG) acceleration sensing technologies from two aspects: the principle of the…

Abstract

Purpose

The purpose of this study is to present the state of the art for fiber Bragg grating (FBG) acceleration sensing technologies from two aspects: the principle of the measurement dimension and the principle of the sensing configuration. Some commercial sensors have also been introduced and future work in this field has also been discussed. This paper could provide an important reference for the research community.

Design/methodology/approach

This review is to present the state of the art for FBG acceleration sensing technologies from two aspects: the principle of the measurement dimension (one-dimension and multi-dimension) and the principle of the sensing configuration (beam type, radial vibration type, axial vibration type and other composite structures).

Findings

The current research on developing FBG acceleration sensors is mainly focused on the sensing method, the construction and design of the elastic structure and the design of a new information detection method. This paper hypothesizes that in the future, the following research trends will be strengthened: common single-mode fiber grating of the low cost and high utilization rate; high sensitivity and strength special fiber grating; multi-core fiber grating for measuring single-parameter multi-dimensional information or multi-parameter information; demodulating equipment of low cost, small volume and high sampling frequency.

Originality/value

The principle of the measurement dimension and principle of the sensing configuration for FBG acceleration sensors have been introduced, which could provide an important reference for the research community.

Details

Sensor Review, vol. 41 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 9 June 2021

Nur Husnina Saadun, Nurul Aini Jaafar, Md Faisal Md Basir, Ali Anqi and Mohammad Reza Safaei

The purpose of this study is to solve convective diffusion equation analytically by considering appropriate boundary conditions and using the Taylor-Aris method to…

Abstract

Purpose

The purpose of this study is to solve convective diffusion equation analytically by considering appropriate boundary conditions and using the Taylor-Aris method to determine the solute concentration, the effective and relative axial diffusivities.

Design/methodology/approach

>An analysis has been conducted on how body acceleration affects the dispersion of a solute in blood flow, which is known as a Bingham fluid, within an artery. To solve the system of differential equations analytically while validating the target boundary conditions, the blood velocity is obtained.

Findings

The blood velocity is impacted by the presence of body acceleration, as well as the yield stress associated with Casson fluid and as such, the process of dispersing the solute is distracted. It graphically illustrates how the blood velocity and the process of solute dispersion are affected by various factors, including the amplitude and lead angle of body acceleration, the yield stress, the gradient of pressure and the Peclet number.

Originality/value

It is witnessed that the blood velocity, the solute concentration and also the effective and relative axial diffusivities experience a drop when either of the amplitude, lead angle or the yield stress rises.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 16 July 2021

Saeed Heshmati and Maysam Shafiee

This study was designed to detect the failures in Iranian accelerators. This paper attempts to identify these effects from the perspective of accelerator managers and…

Abstract

Purpose

This study was designed to detect the failures in Iranian accelerators. This paper attempts to identify these effects from the perspective of accelerator managers and founders of startups. The main goals of this article are as follows: (1) What are the failures of Iran's acceleration programs from the perspective of accelerator managers? (2) What are the failures of Iran's acceleration programs from the perspective of startup teams? (3) What are some of failures of the acceleration programs that both groups agree on?

Design/methodology/approach

It has been attempted to conduct semi-structured interviews with managers of corporate accelerators on the one hand and startups accelerated in these accelerators on the other. The interviewees were selected using snowball method and consisted of 9 accelerator managers out of 7 accelerators and 15 startups based on 5 accelerators. The analysis of the information extracted from the interviews and coding of the failure identified in the accelerators was performed using the thematic analysis method. In order to assess the validity of this study, an entrepreneurial doctoral student was asked to codify the interviews individually to compare the extracted codes.

Findings

Finally, 34 problems have been identified that are divided into four main themes related to mentorship, acceleration program, acceleration structure and infrastructure and internal startup team problems. Overall, the greatest agreement among the failures identified as wrong orientation by untrained mentors, the lack of complementary in ability and skills of team members, the lack of knowledge of mentors, the lack of acceleration managers in entrepreneurship and the lack of a proper leader in startup teams.

Originality/value

This study aimed to investigate the failures of corporate accelerators in Iran as a developing country, which is the first survey in Iran. We have many researches about the pathology and identify failures of accelerators, but in corporate accelerators, little research has been done. The authors have a classification of failures in corporate accelerators by using thematic analysis. In this study, accelerators' managers and founders of startups were interviewed and 34 failures were identified.

Details

World Journal of Science, Technology and Sustainable Development, vol. 18 no. 4
Type: Research Article
ISSN: 2042-5945

Keywords

Article
Publication date: 13 August 2019

Diamanto Politis, Jonas Gabrielsson, Nataliya Galan and Solomon Akele Abebe

This study aims to better understand entrepreneurial learning in the context of venture acceleration programs.

Abstract

Purpose

This study aims to better understand entrepreneurial learning in the context of venture acceleration programs.

Design/methodology/approach

A qualitative research strategy was used based on multiple in-depth interviews with 21 lead entrepreneurs complemented with participatory observations and secondary sources. The data were inductively analysed following the Gioia methodology (Gioia et al., 2012).

Findings

The authors build on experiential learning theory to generate a process-focussed model exploring the learning dynamics that venture acceleration programs can facilitate. In this model, the authors identify three catalysts that trigger processes of experiential learning and two contingencies that alleviate the effects of the catalysts on learning outcomes. The findings suggest that the potential of venture acceleration programs to be effective learning environments pends on the presence and quality of these catalysts and contingencies.

Originality/value

The findings provide novel insights on how venture acceleration programs trigger entrepreneurial learning, thereby offering a deeper understanding of the learning dynamics in this setting.

Details

The Learning Organization, vol. 26 no. 6
Type: Research Article
ISSN: 0969-6474

Keywords

Article
Publication date: 14 October 2020

Piotr Wójcik, Krzysztof Obłój, Aleksandra Wąsowska and Szymon Wierciński

The purpose of this paper is to explore the emotional dynamics of the corporate acceleration process, using the systems psychodynamics perspective.

Abstract

Purpose

The purpose of this paper is to explore the emotional dynamics of the corporate acceleration process, using the systems psychodynamics perspective.

Design/methodology/approach

The study applies inductive multiple case study of embedded 10 cases of corporate acceleration, covering both incumbent and startup perspectives, occurring in the context of a corporate accelerator.

Findings

We find that (1) the process of corporate acceleration involves three phases, each of them is dominated by a different emotional state (hope, anxiety and acceptance), triggering different behavioral responses; (2) as a means to deal with negative emotions, entrepreneurs and corporate acceleration program's team members develop different mechanisms of dealing with contradictories in subsequent acceleration phases (defense and copying mechanisms), which are reflected in their behaviors. Coping mechanisms with goal reformulation (i.e. refocus from the officially declared “open innovation” goals toward mainly symbolic ones) is an effective strategy to manage negative emotions in third phase of the acceleration.

Research limitations/implications

Our sample is limited to two relatively similar accelerators established by telecom companies, and therefore, our theoretical and practical conclusions cannot be generalized.

Practical implications

We supplement the studies of corporate accelerators that imply how to design them better and improve decision-making rules with recommendation that in order to improve their effectiveness in terms of learning and innovations, their managers need not only to learn how to manage structural and procedural differences but also how to overcome social defenses triggered by corporate–startups cooperation.

Originality/value

By documenting a multidimensional impact of acceleration process, and especially shedding light on psychodynamic aspects behind such liaisons, this paper contributes to richer understanding of corporate–startup relationships, typically examined through a rationalistic lens of strategy literature. The study contributes to interorganizational research and open innovation literature, by showing that corporate acceleration process is marked by phases based on the type of emotions intertwined with the nature and dynamism of its life cycle. It indicates how these emotions are managed depending on their type.

Details

Journal of Organizational Change Management, vol. 33 no. 6
Type: Research Article
ISSN: 0953-4814

Keywords

Article
Publication date: 16 March 2012

Elder M. Hemerly, Benedito C.O. Maciel, Anderson de P. Milhan and Valter R. Schad

The purpose of this paper is to employ an extended Kalman filter for implementing an AHRS (attitude and heading reference system) with acceleration compensation, thereby…

Abstract

Purpose

The purpose of this paper is to employ an extended Kalman filter for implementing an AHRS (attitude and heading reference system) with acceleration compensation, thereby improving the reliability of such systems, since this removes the usual restrictive assumption that the vehicle is undergoing a non‐accelerated maneuver.

Design/methodology/approach

MARG (magnetic, acceleration and rate gyros) sensors constitute the basic hardware, which are integrated by the Kalman filter. The error dynamics for attitude and gyro biases is obtained in the navigation frame, providing a much simpler approach than usually taken in the literature, since it relies on direct quaternion differentiation. The state vector associated to the error dynamics possesses six components: three are associated to the quaternion error and three concern gyro bias estimates.

Findings

The AHRS is implemented in an ARM (Advanced RISC Machine) processor and tested with experimental data. The accelerated case is treated by two complementary approaches: by changing the noise variance in the Kalman filter, and by obtaining an acceleration information from GPS (global positioning system) velocity measurements. Experimental results are presented and the performance is compared with commercial ARHS systems.

Practical implications

The proposed AHRS can be implemented with low cost MARG sensors, and GPS aiding, with use for instance in UAV (unmanned aerial vehicle) and small aircrafts' attitude estimation, for navigation and control applications.

Originality/value

Usually the AHRS designs employ as states total gyro bias and Euler angles, or quaternion, and do not consider the accelerated case. Here the state is comprised by gyro bias and quaternion error variables, which attenuates the effect of nonlinearities, and two complementary procedures tackle the accelerated case: acceleration correction by using a GPS derived acceleration signal and change in the output noise covariance used by the Kalman filter.

Article
Publication date: 16 March 2020

Mehmet Konar

The purpose of this paper is to present a novel approach based on the artificial bee colony (ABC) algorithm aiming to achieve maximum acceleration and maximum endurance…

Abstract

Purpose

The purpose of this paper is to present a novel approach based on the artificial bee colony (ABC) algorithm aiming to achieve maximum acceleration and maximum endurance for morphing unmanned aerial vehicle (UAV) design.

Design/methodology/approach

Some of the most important issues in the design of UAV are the design of thrust system and determination of the endurance of the UAV. Although propeller selection is very important for the thrust system design, battery selection has the utmost importance for the determination of UAV endurance. In this study, the calculations of maximum acceleration and endurance required by ZANKA-II during the flight are considered simultaneously. For this purpose, a model based on the ABC algorithm is proposed for the morphing UAV design, aiming to achieve the maximum acceleration and endurance. In the proposed model, the propeller diameter, propeller pitch and battery values used in morphing UAV's power system design are selected as the input parameters; maximum acceleration and endurance are selected as the output parameters. To obtain the maximum acceleration and endurance, the optimum input parameters are determined through the ABC algorithm-based model.

Findings

Considerable improvements on maximum acceleration and endurance of morphing UAV with ABC algorithm-based model are obtained.

Research limitations/implications

The endurance and acceleration due to the thrust are two separate parameters that are not normally proportional to each other. In this study, optimization of UAV’s endurance and acceleration is considered with equal importance.

Practical implications

Using artificial intelligence techniques causes fast and simple optimization for determination of UAV’s endurance and acceleration with equal importance. In the simulation studies with ABC algorithm, satisfactory results are obtained.

Social implications

The results of the study have showed that the proposed approach could be an alternative method for UAV designers.

Originality/value

Providing a new and efficient method saves time and reduces cost in calculations of maximum acceleration and endurance of the UAV.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 4
Type: Research Article
ISSN: 1748-8842

Keywords

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