bluuebunny/crossref_metadata_2025_split huggingface dataset:
A solution for SRM starting hesitation: from FE analysis to bench validation
Authors: Makni Zaatar , Bouallaga Kamel 
Published: October 2015

Purpose– The starting hesitation of a switched reluctance motor (SRM) is an issue which must be considered in the early motor design. It is mostly handled as a control concern. The starting procedure of a SRM using a single Hall-effect position sensor is analysed in this paper. This low cost position measurement solution requires a specific control strategy. That has been developed for a three-phase 6/4 SRM. The paper aims to discuss these issues.Design/methodology/approach– The starting procedure begins with a rotor alignment step intending to bring the rotor to a known position. Afterward, only one phase is supplied on a periodic basis, to drive the rotor in the desired direction and accelerate up to a predefined speed threshold. Thus, the proposed procedure drastically simplifies the control strategy and permits a low cost sensor based control. 2D finite elements simulations are performed to analyse the starting performances in terms of response time and power efficiency. Both electrical and mechanical transients are considered in the simulation model thanks to simplifying assumption which consists in applying a time averaged voltages instead of instantaneous switching. Finally, the entire starting procedure with a one phase supply procedure is tested experimentally.Findings– A starting procedure of a three-phase SRM is implemented. The control effectiveness is validated by complementary FE calculations and measurements.Originality/value– The starting hesitation issue of a three-phase SRM is solved with an easy control strategy. During the acceleration phase, only one phase is self-controlled.
Design of a brushless excitation system utilizing pot cores
Authors: Veitengruber Julian , Rinderknecht Frank , Friedrich Horst E. 
Published: October 2015

Purpose
– The purpose of this paper is to devote the optimal substitution of slip rings through an inductive power transfer system for field winding supply of generators or motors with a wound rotor. By a rotational pot-core transformer approach, the rotor-side energizing of the excitation windings can be provided isolated and free of wear.

Design/methodology/approach
– For design purpose, an analytical model of the inductive link and the compensation network elements is shown. Based on a pot-core transformer approach, possible types of compensation networks regarding motor-specific constraints were carried out and compared among themselves by parameter studies. The analytical parts of the model were subsequently validated with measured data of an appropriate core and accompanying FEM calculations. On the basis of an experimental prototype system, the approach has been tested both stationary and transient.

Findings
– The publication exemplifies how a brushless excitation system for generators and motors can be inexpensively designed and implemented.

Originality/value
– This paper systematically presents a comprehensive analytical approach for brushless excitation systems as well as a prototypical system. Compensation network elements regarding motor-specific constraints were carried out and compared among themselves by parameter studies.
A nonlinear control algorithm for a wind turbine
Authors: Aimene Merzak , Payman Alireza , Dakyo Brayima 
Published: October 2015

Purpose
– The purpose of this paper is to propose a new nonlinear control algorithm to control a wind turbine based on permanent magnet synchronous generator (PMSG) connected to the grid via a back-to-back converter. The control algorithm is composed of a flatness-based method for the machine side convertor (MSC) and a voltage-oriented method for the grid side converter (GSC).

Design/methodology/approach
– For the MSC control, the output variable is chosen properly to prove that the system is flat at first. Then, the appropriate reference trajectories are planned on its components. The reference trajectories are such designed that the system operates in maximum power point tracking (MPPT) mode. Finally, state feedback regulators are used to force the system output to follow its reference. To control the GSC, a classical voltage-oriented control method is used.

Findings
– The simulation results obtained with a random wind speed are presented in order to prove the validity of the proposed control algorithm. These results show that the system is controlled successfully while it operates in the MPPT mode or in its maximum power limitation mode.

Originality/value
– In this paper, a new algorithm based on flatness property is presented to control a variable speed wind turbine based on a PMSG. The proposed control method allows the system to operate in optimal operating modes.
Grey clustering evaluation of urban low-carbon transport development based on triangular whitenization weight function
Authors: Guo Jun , Zhao Xi , Huang Yimin 
Published: October 2015

Purpose
– The purpose of this paper is to establish a grey clustering evaluation model based on center-point triangular whitenization weight function to evaluate the situation of urban low-carbon transport development (LTD). The study results intend to provide some theoretical basis and tool support for transport management departments and related researchers who are engaged in low-carbon transport (LT).

Design/methodology/approach
– The study uses analytical hierarchy process based on expert investigations to determine the weight of each criteria, classifies the grey clusters based on center-point triangular whitenization weight function, calculates the membership of each development criteria and ranks the development level of all dimensions.

Findings
– The research results of case city show that low-carbon technology is in “poor” level, transport facility is in “superior” level, low-carbon policy and environmental coordination is in “intermediate” level, transport management is in “good” level and the overall LTD level is in “intermediate” level.

Practical implications
– Reducing the carbon emissions of urban transport and achieving LT is the key to promote urban sustainable development, the scientific judgment of transport development situation is the premise of promoting LTD. Therefore, based on the practices of LT in China, the study systematically clarifies LTD from five dimensions of reflecting LTD.

Originality/value
– From the perspective of sustainable development, the evaluation index system of LTD is built with five dimensions consisting of low-carbon technology, low-carbon policy, transport facility, transport management and environmental coordination. Then assess the LTD by using the grey clustering evaluation model based on center-point triangular whitenization weight. This paper presents a new research idea for LTD evaluation.
Multiple attribute group decision making method based on OWA operator and grey incidence analysis
Authors: Wang Qiuping , Liu Subing , Xiong Guoqiang 
Published: October 2015

Purpose
– The aggregation of information from a group of decision experts for developing collective opinion is the important question in practice. The purpose of this paper is to provide a group decision-making method via ordered weighted aggregation (OWA) operator and grey incidence analysis.

Design/methodology/approach
– In this study, OWA operator provides aggregation of attribute values to form an overall decision for each decision expert, and grey incidence model provides aggregation of decision experts’ evaluations to form overall score for each alternative. The example illustrates the procedure and practicability of the proposed model.

Findings
– A new thought for multiple attribute group decision-making problems is given. The proposed method produces an overall desirability score for each alternative.

Practical implications
– This is to obtain a more comprehensive and realistic solution to the given group decision-making problem. The proposed analysis method of group decision-making problems reveals vitality of grey systems theory.

Originality/value
– This paper combines OWA operator and grey incidence analysis to obtain a novel and effective method for group decision making. It is suitable for group decision-making problems in which the attribute weights are completely unknown, expert weights are completely unknown.
Grey cluster evaluation models based on mixed triangular whitenization weight functions
Authors: Liu Si-feng , Yang Yingjie , Fang Zhi-geng , Xie Naiming 
Published: October 2015

Purpose
– The purpose of this paper is to present two novel grey cluster evaluation models to solve the difficulty in extending the bounds of each clustering index of grey cluster evaluation models.

Design/methodology/approach
– In this paper, the triangular whitenization weight function corresponding to class 1 is changed to a whitenization weight function of its lower measures, and the triangular whitenization weight function corresponding to class s is changed to a whitenization weight function of its upper measures. The difficulty in extending the bound of each clustering indicator is solved with this improvement.

Findings
– The findings of this paper are the novel grey cluster evaluation models based on mixed centre-point triangular whitenization weight functions and the novel grey cluster evaluation models based on mixed end-point triangular whitenization weight functions.

Practical implications
– A practical evaluation and decision problem for some projects in a university has been studied using the new triangular whitenization weight function.

Originality/value
– Particularly, compared with grey variable weight clustering model and grey fixed weight clustering model, the grey cluster evaluation model using whitenization weight function is more suitable to be used to solve the problem of poor information clustering evaluation. The grey cluster evaluation model using endpoint triangular whitenization weight functions is suitable for the situation that all grey boundary is clear, but the most likely points belonging to each grey class are unknown; the grey cluster evaluation model using centre-point triangular whitenization weight functions is suitable for those problems where it is easier to judge the most likely points belonging to each grey class, but the grey boundary is not clear.
Fair value in financial statements after financial crisis
Authors: Majercakova Daniela , Skoda Miroslav 
Published: October 2015

Purpose– The purpose of this paper is to examine and depict the advantages and disadvantages connected to the fair value, providing the reader with objective information and thorough insight into the problems and benefits of fair value. Partial objectives of this paper are to define the concept of fair value, to provide information about theoretical background and evolution of fair value and to examine and describe the possible future development of fair value.Design/methodology/approach– Findings in the paper are based on study of existing literature and also on study using the open-ended approach of grounded theory, including 50 interviews and two group discussions with professional accountants dealing with the fair value accounting in practice.Findings– According to the advantages and disadvantages of the concept of fair value in accounting, it is quite obvious and clear that this concept is far from being perfect. It is very difficult to determine whether its contribution to the improvement of accounting is really beneficial. Although the fair-value discussion seems to be far from over now, the current crisis provided an interesting setting to further explore these issues, understand them better and hopefully urge responsible institutions to fix the imperfections within the system to make it work correctly and more effectively.Research limitations/implications– Because of the chosen research approach, the research results may lack generalisability. Therefore, researchers are encouraged to test the proposed propositions further.Practical implications– This paper highlights that historical cost and fair value accounting must not be considered as competitors, as they serve different purposes. Knowledge of fair value is important, although it is not enough. Users also need to know the cost of the investment. In fact, knowing how much resources have been sacrificed to obtain that fair value, they could effectively evaluate stewardship. As a consequence, the adoption of a dual measurement and reporting system should be considered and discussed at a standard setting level.Originality/value– This paper fulfils an identified need to study how fair value accounting can be useful in the future.
Impression management in annual reports of the largest European companies
Authors: Falschlunger Lisa Maria , Eisl Christoph , Losbichler Heimo , Greil Andreas Michael 
Published: October 2015

Purpose
– Graphs are powerful tools which affect a reader’s impression and decision making. However, graphs in annual reports have a long tradition of being designed in order to give a more favourable impression of the company’s performance. The purpose of this paper is to add to the understanding of how large listed companies in Europe choose to use and misuse graphical representation.

Design/methodology/approach
– This comprehensive study investigates annual reports of the top 50 European companies listed in the fortune 500 index. Company reports are analysed over a period of seven years resulting in 4,683 graphs. The authors investigate the development of the three major areas of impression management – selectivity, graphical measurement distortion and presentational enhancement – individually by company as well as collectively for the entire sample.

Findings
– The main findings are that topics displayed, and how they are presented, significantly change over time and that graphs are much more likely to exaggerate positive trends than to understate them. Additionally, it can be found that longer time sequences (greater than five years) almost exclusively depict favourable trends (86 per cent) and graphical measurement distortions are applied on purpose for both key financial variables (KFV) as well as for non-KFV (around 30 per cent in all years).

Research limitations/implications
– The sample for this study are the biggest 50 companies in Europe. It is not clear, if these companies are a representative sample for all publicly traded companies in Europe. Further research is needed regarding small and medium size companies.

Practical implications
– The findings show that companies primarily produce graphs in order to influence the perception of their stakeholders rather than to display the topics in accordance with the “true and fair view” principle that is requested by the IASB. However, standard setters like the IASB or the FASB have not yet released any particular information on how to use graphs correctly and avoid misleading information. This study should provide a solid base for further discussions in this regard as companies still use graphs to give a favourable impression of the company and deliberately misuse them in order to achieve this aim.

Originality/value
– This study contributes to the research field of impression management by answering the quest for more longitudinal studies and offers an extended focus while examining not only KFV but all variables depicted in annual reports.
Board’s financial incentives, competence, and firm risk disclosure
Authors: Martikainen Minna , Kinnunen Juha , Miihkinen Antti , Troberg Pontus 
Published: October 2015

Purpose
– The purpose of this paper is to examine novel corporate governance-based determinants of risk disclosures among index-listed Finnish companies. Therefore the focus of the study is on explaining the board’s monitoring role in relation to corporate managers.

Design/methodology/approach
– Firms’ risk disclosures are analysed in terms of their Quantity and Coverage. The authors focus on two board characteristics not examined in prior related literature: first, non-executive board members’ self-interested financial incentives, measured by their share or option ownership, and annual compensation and second, non-executive board members’ competence, measured by their experience in the company and managerial capability proxied by prior education. The sample is composed of the OMXH-25-listed firms, representing the most traded and followed firms among Finnish publicly listed companies.

Findings
– The authors find that the risk disclosures of these firms can be explained by financial incentives (wealth and compensation) and competence-related factors (attrition rate and education). The results indicate that among the “best disclosers”, the narrative risk disclosures are, on average, on a high level, and variation in risk reporting is largely associated with board characteristics.

Research limitations/implications
– The relatively small sample size makes the results vulnerable to type two error. Further research could continue by examining the impact of board work on corporate disclosures across countries and disclosure items.

Practical implications
– Board members’ financial incentives and competence impact the dynamism of board work. In this way, they are also associated with board members’ disclosure decisions.

Originality/value
– This paper contributes to the extant literature by demonstrating the impact of previously unexamined board characteristics on the quality of the narrative risk disclosures of highly followed firms.
Influence of type of assessment and stress on the learning outcome
Authors: Tetteh Godson Ayertei , Sarpong Frederick Asafo-Adjei 
Published: October 2015

Purpose– The purpose of this paper is to explore the influence of constructivism on assessment approach, where the type of question (true or false, multiple-choice, calculation or essay) is used productively. Although the student’s approach to learning and the teacher’s approach to teaching are concepts that have been widely researched, few studies have explored how the type of assessment (true or false, multiple-choice, calculation or essay questions) and stress would manifest themselves or influence the students’ learning outcome to fulfill Bloom’s taxonomy. Multiple-choice questions have been used for efficient assessment; however, this method has been criticized for encouraging surface learning. And also some students complain of excelling in essay questions and failing in multiple-choice questions. A concern has arisen that changes may be necessary in the type of assessment that is perceived to fulfill Bloom’s taxonomy.Design/methodology/approach– Students’ learning outcomes were measured using true or false, multiple-choice, calculations or essay questions to fulfill Bloom’s taxonomy and the students’ reaction to the test questionnaire. To assess the influence of the type of assessment and the stress level factors of interest, MANOVA was used to identify whether any differences exist and to assess the extent to which these differences are significantly different, both individually and collectively. Second, to assess if the feedback information given to respondents after the mid-semester assessment was effective, the one-way ANOVA procedure was used to test the equality of means and the differences in means of the mid-semester assessment scores and the final assessment scores.Findings– Results revealed that the type of questions (true or false, multiple-choice, calculations or essay) will not significantly affect the learning outcome for each subgroup. The ANOVA results, comparing the mid-semester and final assessments, indicated that there is sufficient evidence means are not equal. Thus, the feedback given to respondents after the mid-semester assessment had a positive impact on the final assessment to actively improve student learning.Research limitations/implications– This study is restricted to students in a particular university in Ghana, and may not necessarily be applicable universally.Practical implications– The practical implications of this research is that assessments for learning, and the importance of assessment impact not only on students, but also on teachers and the literature.Originality/value– This study contributes to the literature by examining how the combination of the type of assessment (true or false, multiple-choice, calculation or essay) and stress contributes to the learning outcome.
Colony contact contributes to the diversity of gut bacteria in bumblebees (Bombus terrestris)
Authors: Billiet Annelies , Meeus Ivan , Van Nieuwerburgh Filip , Deforce Dieter , Wäckers Felix , Smagghe Guy 
Published: October 2015

AbstractSocial bees, like honeybees and bumblebees, have a close contact with nest mates of different developmental stages and generations. This could enhance bacterial transfer between nest mates and offers opportunities for direct transfer of symbionts from one generation to the next, resulting in a stable host specific gut microbiota. Gut symbionts of honeybees and bumblebees have been suggested to contribute in digestion and protection against parasites and pathogens. Here we studied the impact of contact with the bumblebee colony on the colonization potential of the bacterial families (i.e., Neisseriaceae, Orbaceae, Lactobacillaceae and Bifidobacteriaceae) occurring in the gut of adult bumblebees (Bombus terrestris). Bacterial profiles of the gut microbiota of B. terrestris were determined based on the hypervariable V4 region of the 16S rRNA using paired‐end Illumina sequencing. In our experiments, we created different groups in which we gradually reduced the contact with nest mates and hive material. We made 3 observations: (i) reducing the contact between the colony and the bumblebee during adult life resulted in a significant drop in the relative abundance of Lactobacillus bombicola and Lactobacillus bombi; (ii) Bifidobacteriaceae required contact with nest mates to colonize the gut of B. terrestris and a significant lower bacterial diversity was observed in bumblebees that were completely excluded from colony contact during the adult life; (iii) Snodgrassella and Gilliamella were able to colonize the gut of the adult bumblebee without any direct contact with nest mates in the adult life stage. These results indicate the impact of the colony life on the diversity of the characteristic bumblebee gut bacteria.
Redistribution of Direct Payments to Permanent Grasslands: Intended and Unintended Impacts
Authors: Hecht Judith , Moakes Simon , Offermann Frank 
Published: October 2015

SummaryGrasslands are an important landscape element in Europe. However, the grassland area has been reduced in the last 50 years. This article assesses potential impacts of a scenario that redistributes CAP direct payments to maintain or increase permanent grassland areas using a farm‐level modelling approach in Germany, Wales and Switzerland. Our results indicate that a reallocation of support payments can help to prevent abandonment or conversion of permanent grassland to more intensive land use. This may be more difficult to achieve when there is a limited arable area to transfer budget from, as demonstrated by results in Wales. Policy effects at the level of farm type can often vary due to the heterogeneities and complexities of permanent grassland farming systems. Our results also show that unintended ‘slippage’ effects such as increased temporary grassland area may occur, though this could also be seen as a form of sustainable intensification. Other difficulties include: a) potential for negative effects on specific farm types despite a positive overall effect, and b) distortions within land markets due to the attractiveness of support payments within sectors of low profitability.