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11 – 20 of 486Eefje Hendriks and Aaron Opdyke
The purpose of this study is to explore communication of hazard-resistant construction techniques after disaster in the absence of outside influence. It further aims to…
Abstract
Purpose
The purpose of this study is to explore communication of hazard-resistant construction techniques after disaster in the absence of outside influence. It further aims to unpack the barriers and drivers in the adoption of knowledge processes to identify strategic recommendations to enlarge adoption of safer construction practices by local construction actors.
Design/methodology/approach
This paper is based on an analysis of stakeholders’ perspectives during post-disaster reconstruction in the Philippines in the province of Busuanga after Typhoon Haiyan in 2013. Data were collected from six communities that received no external housing assistance, analyzing surveys from 220 households, 13 carpenters, 20 key actors coordinating reconstruction or recovery efforts, as well as 12 focus group discussions.
Findings
This research argues for a stronger role of governmental agencies, vocational training schools and engineers. Current communication of typhoon-resistant construction knowledge is ineffective to stimulate awareness, understanding and adoption by local construction actors and self-recovering households.
Research limitations/implications
The analysis in this study focuses on a small sample of communities in the west of the Philippines that are not frequently affected by typhoons.
Originality/value
This is one of the few scholarly works in the Philippines focused on adoption of safer construction practices by community-based construction actors when technical housing assistance is absent.
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Taher Abedinzadeh and Sajjad Tohidi
The purpose of this paper is to present an improved approach for estimation of the rotor position and speed of doubly fed induction generator, which can be used in vector…
Abstract
Purpose
The purpose of this paper is to present an improved approach for estimation of the rotor position and speed of doubly fed induction generator, which can be used in vector control and direct torque control (DTC) schemes.
Design/methodology/approach
Some novel equations are developed for calculation of the rotor position and rotor speed. Such equations do not need to the value of stator flux linkage and just, measured values of the stator voltage and currents as well as rotor current are required to be known.
Findings
The simulation results verify the satisfactory steady-state and dynamic performance of proposed approach with both the vector control and DTC schemes. The results show that the proposed estimation approach benefits from the starting on the fly, robustness against the variations of the most of the stator and rotor parameters and immunity against the noise.
Originality/value
The proposed estimation approach is novel and the outcome of the research of authors. It is simple and effective and, no approximation is made in the calculations. The simulation results demonstrate that the proposed scheme can be successfully implemented in various control strategies, e.g. DTC and vector control.
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Krzysztof Górecki and Paweł Górecki
The purpose of this paper is to propose a simple electrothermal model of GaN Schottky diodes, and its usefulness for circuit-level electrothermal simulation of…
Abstract
Purpose
The purpose of this paper is to propose a simple electrothermal model of GaN Schottky diodes, and its usefulness for circuit-level electrothermal simulation of laboratory-made devices is proved.
Design/methodology/approach
The compact electrothermal model of this device has the form of a subcircuit for simulation program with integrated circuit emphasis. This model takes into account influence of a change in ambient temperature in a wide range as well as influence of self-heating phenomena on dc characteristics of laboratory-made GaN Schottky diodes. The method of model parameters estimation is described.
Findings
It is shown that temperature influences fewer characteristics of GaN Schottky diodes than classical silicon diodes. The discussed model accurately describes properties of laboratory made GaN Schottky diodes. Additionally, the measured and computed characteristics of these diodes are shown and discussed.
Research limitations/implications
The presented model together with the results of measurements and computations is dedicated only to laboratory-made GaN Schottky diodes.
Originality/value
The presented investigations show that characteristics of laboratory-made GaN Schottky diodes visibly change with temperature. These changes can be correctly estimated using the compact electrothermal model proposed in this paper. The correctness of this model is proved for four structures of such diodes characterised by different values of structure area and a different assembly process.
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Dimitrios Kafetzopoulos and Katerina Gotzamani
The purpose of this paper is to develop a conceptual framework to investigate how the European Foundation for Quality Management (EFQM) excellence model enablers influence…
Abstract
Purpose
The purpose of this paper is to develop a conceptual framework to investigate how the European Foundation for Quality Management (EFQM) excellence model enablers influence the four types (product, process, organizational and marketing) of innovation performance of a manufacturing firm.
Design/methodology/approach
The study uses survey data from a sample of 580 manufacturing firms in Greece and employs structural equation modeling to test the developed hypotheses.
Findings
The results reveal that enablers of the EFQM model are either directly or indirectly associated with the four types of innovation. Furthermore, the findings show that it is essential for a firm to manage all the facilitating enablers included in the EFQM model, since they cannot boost innovation when implemented in isolation.
Research limitations/implications
The sample is limited to one country (Greece). In addition, researchers have to assess the same relationships considering the effect of external factors such as environmental uncertainty. The potential consequences of enablers on innovation performance may be mediated by customer or people results.
Practical implications
The empirical findings of the present study help managers to develop the appropriate quality strategies and allocate the respective resources according to the desired type of innovation.
Originality/value
Based on the multi-dimensional structure of quality, this empirical study determines the contribution of EFQM model enablers to specific innovation performance dimensions of manufacturing companies.
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Krzysztof Górecki, Damian Bisewski, Janusz Zarębski, Ryszard Kisiel and Marcin Myśliwiec
This paper aims to present the results of measurements and calculations illustrating mutual thermal coupling between power Schottky diodes made of silicon carbide situated…
Abstract
Purpose
This paper aims to present the results of measurements and calculations illustrating mutual thermal coupling between power Schottky diodes made of silicon carbide situated in the common case.
Design/methodology/approach
The idea of measurements of mutual transient thermal impedances of the investigated device is described.
Findings
The results of measurements of mutual transient thermal impedances between the considered diodes are shown. The experimentally verified results of calculations of the internal temperature waveforms of the considered diodes obtained with mutual thermal coupling taken into account are presented and discussed. The influence of mutual thermal coupling and a self-heating phenomenon on the internal temperature of the considered diodes is pointed out.
Research limitations/implications
The presented methods of measurements and calculations can be used for constructing the investigated diodes made of other semiconductor materials.
Originality/value
The presented results prove that mutual thermal coupling between diodes mounted in the common case must be taken into account to calculate correctly the waveforms of the device internal temperature.
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Kaiçar Ammous, Elyes Haouas and Slim Abid
The purpose of this paper is to develop a simulation tool which permits reducing the cost of long time‐range simulation of complex converters and running at high frequency.
Abstract
Purpose
The purpose of this paper is to develop a simulation tool which permits reducing the cost of long time‐range simulation of complex converters and running at high frequency.
Design/methodology/approach
A different method is used to represent a simplified converter but the adopted technique uses the average representation of the cell converter.
Findings
The paper shows that the use of averaged representation of the pulse width modulation switch in multilevel converters is staying applied. The main advantage of the proposed averaged model is its simplified representation when only electrical behaviour is considered.
Research limitations/implications
The analytical algorithm of the averaged model can be introduced in different simulator as it has a description language, enabling study of the Compatibilité Electromagnétique and electrothermal phenomena.
Originality/value
This paper presents an averaged model of the multilevel converter which can be implemented in any simulator as it has a description language.
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Krzysztof Górecki and Paweł Górecki
This paper aims to propose the electrothermal dynamic model of the insulated gate bipolar transistors (IGBT) for SPICE.
Abstract
Purpose
This paper aims to propose the electrothermal dynamic model of the insulated gate bipolar transistors (IGBT) for SPICE.
Design/methodology/approach
The electrothermal model of this device (IGBT), which takes into account both electrical and thermal phenomena, is described. Particularly, the sub-threshold operation of this device is considered and electrical, and thermal inertia of this device is taken into account. Attention was focused on the influence of electrical and thermal inertia on waveforms of terminal voltages of the considered transistor operating in the switching circuit and on waveforms of the internal temperature of this device.
Findings
The correctness of the presented model is verified experimentally and a good agreement of the calculated and measured electrical and thermal characteristics of the considered device is obtained.
Research limitations/implications
The presented model can be used for different types of IGBT, but it is dedicated for SPICE software only.
Originality/value
The form of the worked out model is presented and the results of experimental verification of this model are shown.
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Christophe Versèle, Olivier Deblecker and Jacques Lobry
This paper presents a computer‐aided design (CAD) tool for the design of isolated dc‐dc converters.
Abstract
Purpose
This paper presents a computer‐aided design (CAD) tool for the design of isolated dc‐dc converters.
Design/methodology/approach
This tool, developed in Matlab environment, is based on multiobjective optimization (MO) using genetic algorithms. The Elitist Nondominated Sorting Genetic Algorithm is used to perform search and optimization whereas analytical models are used to model the power converters. The design problem requires minimizing the weight, losses and cost of the converter while ensuring the satisfaction of a number of constraints. The optimization variables are, as for them, the operating frequency, the current density, the maximum flux density, the transformer dimensions, the wire diameter, the core material, the conductor material, the converter topology (among Flyback, Forward, Push‐Pull, half‐bridge and full‐bridge topologies), the number of semiconductor devices associated in parallel, the number of cells associated in series or parallel as well as the kinds of input and output connections (serial or parallel) of these cells. Finally, the design of an auxiliary railway power supply is presented and discussed.
Findings
The results show that such tool to design dc‐dc power converters presents several advantages. In particular, it proposes to the designer a set of solutions – instead of a single one – so that he can choose a posteriori which solution best fits the application under consideration. Moreover, interesting solutions not considered a priori can be found with this tool.
Originality/value
To the best of the authors’ knowledge, such a CAD tool including a MO procedure taking several topologies into account has not been suggested so far.
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Tohid Jalilzadeh, Mehrdad Tarafdar Hagh and Mehran Sabahi
This paper aims to propose a new transformer-less inverter structure to reduce the common-mode leakage current in grid-connected photovoltaic (PV) systems.
Abstract
Purpose
This paper aims to propose a new transformer-less inverter structure to reduce the common-mode leakage current in grid-connected photovoltaic (PV) systems.
Design/methodology/approach
The proposed circuit structure is the same as the conventional full-bridge inverter with three additional power switches in a triangular structure. These three power switches are between the bridge and the output filter, and they mitigate the common-mode leakage current flowing toward the PV panels’ capacitors. The common-mode leakage current mitigation is done through the three-direction clamping cell (TDCC) concept. By clamping the common-mode voltage to the middle voltage of the DC-link capacitors, the leakage current and the total harmonic distortion (THD) of the injected current to the grid is effectively reduced. Therefore, the efficiency is improved.
Findings
The switching modes and the control method are introduced. A comparison is carried out between the proposed structure and other solutions in the literature. The proposed topology and its respective control method are simulated by PSCAD/EMTDC software. The simulation results validate the advantages of the presented structure such as clamping the common-mode voltage and reducing leakage current and THD of injected current to the grid.
Originality/value
Presenting a single phase-improved inverter structure with low-leakage current for grid-connected PV power systems represents a significant original contribution to this work. The proposed structure can inject a sinusoidal current with low THD to the AC grid, and the power factor is unity on the AC side. In the half positive cycle, one of the switches in the TDCC is turned off under zero current. Besides, one of the other switches in TDCC is turned on with zero voltage and, therefore, its turn-on switching losses are zero. The efficiency of the proposed topology is high because of the reduction of leakage current and power losses. Accordingly, the presented topology can be a good solution to the leakage current elimination.
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Gustavo Dambiski Gomes de Carvalho, June Alisson Westarb Cruz, Hélio Gomes de Carvalho, Luiz Carlos Duclós and Rosângela de Fátima Stankowitz
Innovation has been widely studied in business and economics, but different innovation and innovativeness measures have been used by scholars. Within this context, this…
Abstract
Purpose
Innovation has been widely studied in business and economics, but different innovation and innovativeness measures have been used by scholars. Within this context, this research aims to identify the main innovation and innovativeness measures used by high-impact or recent papers within the past 10 years.
Design/methodology/approach
Regarding methodology, the bibliometric process Proknow-C was used, selecting 26 papers from a sample exceeding 2,000 articles in the Web of Science database.
Findings
Based on the literature review, these articles’ innovativeness measures were classified in terms of inputs, capabilities and outputs. In summary, the articles of the bibliometric portfolio used diverse innovativeness measures comprising inputs (R&D investments, R&D staff qualification, patents, etc.), capabilities and processes (culture, leadership, knowledge, strategy, etc). and outputs (number of innovations, percentage of revenues of innovative products, etc.). Furthermore, a new innovativeness classification was proposed with eight types of organizations considering the presence of inputs, capabilities and outputs.
Research limitations/implications
Although Proknow-C is an established bibliometric process, it naturally has some limitations to select a bibliometric portfolio of approximately 20 articles from a sample exceeding 2,000 articles. The major limitations involve the filters used, such as aligned titles, number of citations in Google Scholar, Pareto principle, aligned abstracts and full text availability.
Originality/value
This research contributes to theory, as it covers high-impact and recent papers concerning innovativeness, specifically by analysing the main measures used and by gathering recommended future research directions, beyond proposing an innovativeness classification. It also contributes to practice, as it gathers diverse innovation measures, which could be used by managers in their organizations.
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