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1 – 10 of 803Saida Mancer, Abdelhakim Necir and Souad Benchaira
The purpose of this paper is to propose a semiparametric estimator for the tail index of Pareto-type random truncated data that improves the existing ones in terms of mean square…
Abstract
Purpose
The purpose of this paper is to propose a semiparametric estimator for the tail index of Pareto-type random truncated data that improves the existing ones in terms of mean square error. Moreover, we establish its consistency and asymptotic normality.
Design/methodology/approach
To construct a root mean squared error (RMSE)-reduced estimator of the tail index, the authors used the semiparametric estimator of the underlying distribution function given by Wang (1989). This allows us to define the corresponding tail process and provide a weak approximation to this one. By means of a functional representation of the given estimator of the tail index and by using this weak approximation, the authors establish the asymptotic normality of the aforementioned RMSE-reduced estimator.
Findings
In basis on a semiparametric estimator of the underlying distribution function, the authors proposed a new estimation method to the tail index of Pareto-type distributions for randomly right-truncated data. Compared with the existing ones, this estimator behaves well both in terms of bias and RMSE. A useful weak approximation of the corresponding tail empirical process allowed us to establish both the consistency and asymptotic normality of the proposed estimator.
Originality/value
A new tail semiparametric (empirical) process for truncated data is introduced, a new estimator for the tail index of Pareto-type truncated data is introduced and asymptotic normality of the proposed estimator is established.
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Vinayambika S. Bhat, Thirunavukkarasu Indiran, Shanmuga Priya Selvanathan and Shreeranga Bhat
The purpose of this paper is to propose and validate a robust industrial control system. The aim is to design a Multivariable Proportional Integral controller that accommodates…
Abstract
Purpose
The purpose of this paper is to propose and validate a robust industrial control system. The aim is to design a Multivariable Proportional Integral controller that accommodates multiple responses while considering the process's control and noise parameters. In addition, this paper intended to develop a multidisciplinary approach by combining computational science, control engineering and statistical methodologies to ensure a resilient process with the best use of available resources.
Design/methodology/approach
Taguchi's robust design methodology and multi-response optimisation approaches are adopted to meet the research aims. Two-Input-Two-Output transfer function model of the distillation column system is investigated. In designing the control system, the Steady State Gain Matrix and process factors such as time constant (t) and time delay (?) are also used. The unique methodology is implemented and validated using the pilot plant's distillation column. To determine the robustness of the proposed control system, a simulation study, statistical analysis and real-time experimentation are conducted. In addition, the outcomes are compared to different control algorithms.
Findings
Research indicates that integral control parameters (Ki) affect outputs substantially more than proportional control parameters (Kp). The results of this paper show that control and noise parameters must be considered to make the control system robust. In addition, Taguchi's approach, in conjunction with multi-response optimisation, ensures robust controller design with optimal use of resources. Eventually, this research shows that the best outcomes for all the performance indices are achieved when Kp11 = 1.6859, Kp12 = −2.061, Kp21 = 3.1846, Kp22 = −1.2176, Ki11 = 1.0628, Ki12 = −1.2989, Ki21 = 2.454 and Ki22 = −0.7676.
Originality/value
This paper provides a step-by-step strategy for designing and validating a multi-response control system that accommodates controllable and uncontrollable parameters (noise parameters). The methodology can be used in any industrial Multi-Input-Multi-Output system to ensure process robustness. In addition, this paper proposes a multidisciplinary approach to industrial controller design that academics and industry can refine and improve.
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The purpose of this manuscript, a state feedback gain depends on the optimal design of fractional order PID controller to time-delay system is established. In established optimal…
Abstract
Purpose
The purpose of this manuscript, a state feedback gain depends on the optimal design of fractional order PID controller to time-delay system is established. In established optimal design known as advanced cuttlefish optimizer and random decision forest that is combined performance of random decision forest algorithm (RDFA) and advanced cuttlefish optimizer (ACFO).
Design/methodology/approach
The proposed ACFO uses the concept of crossover and mutation operator depend on position upgrading to enhance its search behavior, calculational speed as well as convergence profile at basic cuttlefish optimizer.
Findings
Fractional order proportional-integrator-derivative (FOPID) controller, apart from as tuning parameters (kp, ki and kd) it consists of two extra tuning parameters λ and µ. In established technology, the increase of FOPID controller is adjusted to reach needed responses that demonstrated using RDFA theory as well as RDF weight matrices is probable to the help of the ACFO method. The uniqueness of the established method is to decrease the failure of the FOPID controller at greater order time delay method with the help of controller maximize restrictions. The objective of the established method is selected to consider parameters set point as well as achieved parameters of time-delay system.
Originality/value
In the established technique used to evade large order delays as well as reliability restrictions such as small excesses, time resolution, as well as fixed condition defect. These methods is implemented at MATLAB/Simulink platform as well as outcomes compared to various existing methods such as Ziegler-Nichols fit, curve fit, Wang method, regression and invasive weed optimization and linear-quadratic regression method.
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Adequate means for easily viewing, browsing and searching knowledge graphs (KGs) are a crucial, still limiting factor. Therefore, this paper aims to present virtual properties as…
Abstract
Purpose
Adequate means for easily viewing, browsing and searching knowledge graphs (KGs) are a crucial, still limiting factor. Therefore, this paper aims to present virtual properties as valuable user interface (UI) concept for ontologies and KGs able to improve these issues. Virtual properties provide shortcuts on a KG that can enrich the scope of a class with other information beyond its direct neighborhood.
Design/methodology/approach
Virtual properties can be defined as enhancements of shapes constraint language (SHACL) property shapes. Their values are computed on demand via protocol and RDF query language (SPARQL) queries. An approach is demonstrated that can help to identify suitable virtual property candidates. Virtual properties can be realized as integral functionality of generic, frame-based UIs, which can automatically provide views and masks for viewing and searching a KG.
Findings
The virtual property approach has been implemented at Bosch and is usable by more than 100,000 Bosch employees in a productive deployment, which proves the maturity and relevance of the approach for Bosch. It has successfully been demonstrated that virtual properties can significantly improve KG UIs by enriching the scope of a class with information beyond its direct neighborhood.
Originality/value
SHACL-defined virtual properties and their automatic identification are a novel concept. To the best of the author’s knowledge, no such approach has been established nor standardized so far.
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Stefano Costa, Eugenio Costamagna and Paolo Di Barba
A novel method for modelling permanent magnets is investigated based on numerical approximations with rational functions. This study aims to introduce the AAA algorithm and other…
Abstract
Purpose
A novel method for modelling permanent magnets is investigated based on numerical approximations with rational functions. This study aims to introduce the AAA algorithm and other recently developed, cutting-edge mathematical tools, which provide outstandingly fast and accurate numerical computation of potentials and vector fields.
Design/methodology/approach
First, the AAA algorithm is briefly introduced along with its main variants and other advanced mathematical tools involved in the modelling. Then, the analysis of a circular Halbach array with a one-pole pair is carried out by means of the AAA-least squares method, focusing on vector potential and flux density in the bore and validating results by means of classic finite element software. Finally, the investigation is completed by a finite difference analysis.
Findings
AAA methods for field analysis prove to be strikingly fast and accurate. Results are in excellent agreement with those provided by the finite element model, and the very good agreement with those from finite differences suggests future improvements. They are also easy programming; the MATLAB code is less than 200 lines. This indicates they can provide an effective tool for rapid analysis.
Research limitations/implications
AAA methods in magnetostatics are novel, but their extension to analogous physical problems seems straightforward. Being a meshless method, it is unlikely that local non-linearities can be considered. An aspect of particular interest, left for future research, is the capability of handling inhomogeneous domains, i.e. solving general interface problems.
Originality/value
The authors use cutting-edge mathematical tools for the modelling of complex physical objects in magnetostatics.
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Nadin Augustiniok, Claudine Houbart, Bie Plevoets and Koenraad Van Cleempoel
Adaptive reuse processes aim to preserve heritage values while creating new values through the architectural interventions that have become necessary. This claim provokes a…
Abstract
Purpose
Adaptive reuse processes aim to preserve heritage values while creating new values through the architectural interventions that have become necessary. This claim provokes a discussion about the meaning of values, how we can preserve them in practice and how we can translate them into architectural qualities that users experience. Riegl's understanding of the different perspectives of heritage values in the past and present opens up the possibility of identifying present values as a reflection of current social, material and political conditions in the architectural discourse.
Design/methodology/approach
This qualitative and practical study compares two Belgian projects to trace the use of values in adaptive reuse projects from an architectural design perspective. The Predikherenklooster, a 17th-century monastery in Mechelen that now houses the public library, and the C-Mine cultural centre in Genk, a former 20th-century coal mine, are compared. The starting point is Flemish legislation, which defines significance through values, distinguishing between 13 heritage values.
Findings
The study demonstrates the opportunities that axiological questions offer during the design process of an adaptive reuse project. They provide an overarching framework for tangible and intangible aspects that need to be discussed, particularly in terms of the link between what exists, the design strategy and their effect.
Originality/value
Adaptive reuse can draw on approaches from both heritage conservation and contemporary architecture and explore values as a tool for “re-designing” built heritage.
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This study aims to examine the impact of brand ethical behavior, specifically perceived brand ethicality, on corporate brand legitimacy in the context of halal cosmetics, by…
Abstract
Purpose
This study aims to examine the impact of brand ethical behavior, specifically perceived brand ethicality, on corporate brand legitimacy in the context of halal cosmetics, by considering perceived brand integrity as a mediating factor.
Design/methodology/approach
The study used a quantitative cross-sectional research design to gather data from 341 fast-moving consumer goods (FMCG) in Tanzania. The data was analyzed by using AMOS 21, using structural equation modeling techniques.
Findings
The findings indicated that perceived brand ethicality has a significant influence on corporate brand legitimacy through the mediation of perceived brand integrity.
Practical implications
The study emphasizes the significance of incorporating and clarifying Islamic laws as integral components of marketing strategies aimed at attracting conscientious customers of halal products. It recommends defining Islamic laws as societal values and norms and integrating them into various brand practices to showcase professionalism, ultimately fostering social acceptance and approval. The study presents valuable practical implications for managers and marketers of FMCG, assisting them in formulating policies and strategies that reflect societal values and norms.
Originality/value
This study represents a novel endeavor that explores the interplay between perceived brand ethicality, corporate brand legitimacy and perceived brand integrity in the context of halal products. It extends theoretical understanding by shedding light on the significance of Islamic laws as a foundation for establishing a competitive advantage. By offering and designing ethical practices, businesses can enhance their legitimacy among halal consumers, particularly in the domain of halal cosmetics.
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N.L.E. Abeywardana, S. M. Ferdous Azam and L.T. Kevin Low
This study aims to offer empirical evidence on how integrated thinking affects the integrated reporting (IR) practice and how integrated thinking originates from board and…
Abstract
Purpose
This study aims to offer empirical evidence on how integrated thinking affects the integrated reporting (IR) practice and how integrated thinking originates from board and management involvement, cross-functional integration and integral link between capitals and strategies.
Design/methodology/approach
This study is cross-sectional and uses a mixed-method approach. The empirical data for the quantitative approach were collected from the 129 public companies listed on Colombo Stock Exchange in Sri Lanka. The personale responsible for preparing the annual report are selected as the respondents of this study. This study used partial least square modelling to test the hypotheses. The quantitative approach results are triangulated across a qualitative research approach in semi-structural interviews with ten responsible officers of integrated reporting practices.
Findings
The central finding of this study is the significant positive relationship between integrated thinking and integrated reporting practice. The qualitative results supported the quantitative findings and show that board and management involvement, cross-functional integration and integral link between capital and strategy enhance the integrated reporting practice. Top management and board management have positive beliefs about the integrated reporting practice; they initiate, encourage, influence, involve and support it. Furthermore, all company departments are involved with the integrated reporting led by the finance department and practice good coordination, communication and collaboration between departments. Moreover, it also evidenced their concern about the linkage between capital and strategy and how they do it in their organisation when practising integrated reporting.
Research limitations/implications
The firms which intend to practice or enhance integrated reporting will be benefited from this study. Hence, this research assists in constructing IT through the direct role of the board and senior leadership, breaking down silos to diffuse IR throughout structures and processes, and concentrating on strategies while managing their capitals and relationships over the long term.
Originality/value
This study provides the initial quantitative empirical evidence on the impact of integrated thinking on integrated reporting practice. To the best of the authors’ knowledge, this study is the first to operationalise both integrated thinking and integrated reporting based on a questionnaire that developed and tested both constructs as higher-order reflective formative and on the relationship between integrated thinking and integrated reporting. The mixed-method approach to examine the relationship between integrated thinking and integrated reporting provides additional insights into the existing literature.
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Niv Yonat, Shabtai Isaac and Igal M. Shohet
The purpose of this research is to provide a theoretical and practical theory and application that provides understanding and means to manage complex infrastructures.
Abstract
Purpose
The purpose of this research is to provide a theoretical and practical theory and application that provides understanding and means to manage complex infrastructures.
Design/methodology/approach
In this research, complexity, nonlinear, noncontinuous effects and aleatoric and data unknowns are bypassed by directly addressing systems' responses. Graph theory, statistics and digital signal processing (DSP) tools are applied within a theoretical framework of the theory of faults (ToF). Motivational complex infrastructure systems (CISs) are difficult to model. Data are often missing or erroneous, changes are not well documented and processes are not well understood. On top of it, under complexity, stalwart analytical tools have limited predictive power. The aleatoric risk, such as rain and risk cascading from interconnected infrastructures, is unpredictable. Mitigation, response and recovery efforts are adversely affected.
Findings
The theory and application are presented and demonstrated by a step-by-step development of an application to a municipal drainage system. A database of faults is analyzed to produce system statistics, spatio-temporal morphology, behavior and traits. The gained understanding is compared to the physical system's design and to its modus operandi. Implications for design and maintenance are inferred; DSP tools to manage the system in real time are developed.
Research limitations/implications
Sociological systems are interest driven. Some events are intentionally created and directed to the benefit and detriment of the opposing parties in a project. Those events may be explained and possibly predicted by understanding power plays, not power functions. For those events, sociological game theories provide better explanatory value than mathematical gain theories.
Practical implications
The theory provides a thematic network for modeling and resolving aleatoric uncertainty in engineering and sociological systems. The framework may be elaborated to fields such as energy, healthcare and critical infrastructure.
Social implications
ToF provides a framework for the modeling and prediction of faults generated by inherent aleatoric uncertainties in social and technological systems. Therefore, the framework and theory lay the basis for automated monitoring and control of aleatoric uncertainties such as mechanical failures and human errors and the development of mitigation systems.
Originality/value
The contribution of this research is in the provision of an explicatory theory and a management paradigm for complex systems. This theory is applicable to a wide variety of fields from facilities and construction project management to maintenance and from academic studies to commercial use.
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The purpose of this paper is to test the existence of stylized facts, such as the volatility clustering, heavy tails seen on financial series, long-term dependence and…
Abstract
Purpose
The purpose of this paper is to test the existence of stylized facts, such as the volatility clustering, heavy tails seen on financial series, long-term dependence and multifractality on the returns of four real estate indexes using different types of indexes: conventional and Islamic by comparing pre and during COVID-19 pandemic.
Design/methodology/approach
Firstly, the authors examined the characteristics of the indexes. Secondly, the authors estimated the parameters of the stable distribution. Then, the long memory is detected via the estimation of the Hurst exponents. Afterwards, the authors determine the graphs of the multifractal detrended fluctuation analysis (MF-DFA). Finally, the authors apply the WTMM method.
Findings
The results suggest that the real estate indexes are far from being efficient and that the lowest level of multifractality was observed for Islamic indexes.
Research limitations/implications
The inefficiency behavior of real estate indexes gives us an idea about the prediction of the behavior of future returns in these markets on the basis of past informations. Similarly, market participants would do well to reassess their investment and risk management framework to mitigate new and somewhat higher levels of risk of their exposures during the turbulent period.
Originality/value
To the authors’ knowledge, this is the first real estate market study employing STL decomposition before applying the MF-DFA in the context of the COVID-19 crisis. Likewise, the study is the first investigation that focuses on these four indexes.
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