Direct and indirect time marching boundary element methods often become numerically unstable. Evidence of, and reasons for, these instabilities is provided in this paper. Two new…
Abstract
Direct and indirect time marching boundary element methods often become numerically unstable. Evidence of, and reasons for, these instabilities is provided in this paper. Two new time stepping schemes are presented, both of which are more stable than the existing standard schemes available. In particular, we introduce the Half‐step scheme, which is more accurate and far more stable than existing methods. This scheme, which is demonstrated on a simple crack problem for the displacement discontinuity method, can also be introduced into the direct boundary element method. Implementation of the Half‐step scheme into existing boundary element codes will allow researchers to attack more challenging problems than before.
Details
Keywords
The unstable dynamic propagation of multistage hydrofracturing fractures leads to uneven development of the fracture network and research on the mechanism controlling this…
Abstract
Purpose
The unstable dynamic propagation of multistage hydrofracturing fractures leads to uneven development of the fracture network and research on the mechanism controlling this phenomenon indicates that the stress shadow effects around the fractures are the main mechanism causing this behaviour. Further studies and simulations of the stress shadow effects are necessary to understand the controlling mechanism and evaluate the fracturing effect.
Design/methodology/approach
In the process of stress-dependent unstable dynamic propagation of fractures, there are both continuous stress fields and discontinuous fractures; therefore, in order to study the stress-dependent unstable dynamic propagation of multistage fracture networks, a series of continuum-discontinuum numerical methods and models are reviewed, including the well-developed extended finite element method, displacement discontinuity method, boundary element method and finite element-discrete element method.
Findings
The superposition of the surrounding stress field during fracture propagation causes different degrees of stress shadow effects between fractures and the main controlling factors of stress shadow effects are fracture initiation sequence, perforation cluster spacing and well spacing. The perforation cluster spacing varies with the initiation sequence, resulting in different stress shadow effects between fractures; for example, the smaller the perforation cluster spacing and well spacing are, the stronger the stress shadow effects are and the more seriously the fracture propagation inhibition arises. Moreover, as the spacing of perforation clusters and well spacing increases, the stress shadow effects decrease and the fracture propagation follows an almost straight pattern. In addition, the computed results of the dynamic distribution of stress-dependent unstable dynamic propagation of fractures under different stress fields are summarised.
Originality/value
A state-of-art review of stress shadow effects and continuum-discontinuum methods for stress-dependent unstable dynamic propagation of multiple hydraulic fractures are well summarized and analysed. This paper can provide a reference for those engaged in the research of unstable dynamic propagation of multiple hydraulic structures and have a comprehensive grasp of the research in this field.
Details
Keywords
Yuan Li, J. Zhang, Yudong Zhong, Xiaomin Shu and Yunqiao Dong
The Convolution Quadrature Method (CQM) has been widely applied to solve transient elastodynamic problems because of its stability and generality. However, the CQM suffers from…
Abstract
Purpose
The Convolution Quadrature Method (CQM) has been widely applied to solve transient elastodynamic problems because of its stability and generality. However, the CQM suffers from the problems of huge memory requirement in case of direct implementation in time domain or CPU time in case of its reformulation in Laplace domain. The purpose of this paper is to combine the CQM with the pseudo-initial condition method (PICM) to achieve a good balance between memory requirement and CPU time.
Design/methodology/approach
The combined methods first subdivide the whole analysis into a few sub-analyses, which is dealt with the PICM, namely, the results obtained by previous sub-analysis are used as the initial conditions for the next sub-analysis. In each sub-analysis, the time interval is further discretized into a number of sub-steps and dealt with the CQM. For non-zero initial conditions, the pseudo-force method is used to transform them into equivalent body forces. The boundary face method is employed in the numerical implementation. Three examples are analyzed. Results are compared with analytical solutions or FEM results and the results of reformulated CQM.
Findings
Results demonstrate that the computation time and the storage requirement can be reduced significantly as compared to the CQM, by using the combined approach.
Originality/value
The combined methods can be successfully applied to the problems of long-time dynamic response, which requires a large amount of computer memory when CQM is applied, while preserving the CQM stability. If the number of time steps is high, then the accuracy of the proposed approach can be deteriorated because of the pseudo-force method.
Details
Keywords
Because it involves the interests of multiple stakeholders, sustainable value is a “wicked problem” that evades definitive formulation and clear solutions. Traditional approaches…
Abstract
Because it involves the interests of multiple stakeholders, sustainable value is a “wicked problem” that evades definitive formulation and clear solutions. Traditional approaches to problem-solving emphasize formulation of the problem followed by analysis and solution development. However, these approaches are inadequate for solving such problems because of they are so difficult to define. Two ways of approaching wicked problems are discussed: positive design and integrative thinking. Both are more appropriate than linear “formulate-then-solve” approaches, because they emphasize careful reflection and framing, focus on understanding the system as a whole and the needs of its users, and learning. In design, the focus is on deeply understanding users and attempting trial solutions as a means of framing the problem; in integrative thinking, the focus is on exploring the problem by inquiring into the mental models of stakeholders. Tata Motors’ decision to locate its plant in West Bengal was a wicked problem that involved the interests of many stakeholders, and is presented to illustrate the two methods. The failure of this plant location project was extremely costly to Tata and to West Bengal, and it is argued that the decision process would have benefited from either positive design or integrative thinking.
Søren Skjold Andersen, Mahesh C. Gupta and Diego Augusto de Jesus Pacheco
Charles Sanders Peirce (1839–1914), recognized as the father of philosophical pragmatism, has been described as a philosopher’s philosopher. Eliyahu Moshe Goldratt (1947–2011)…
Abstract
Purpose
Charles Sanders Peirce (1839–1914), recognized as the father of philosophical pragmatism, has been described as a philosopher’s philosopher. Eliyahu Moshe Goldratt (1947–2011), considered the father of the management philosophy theory of constraints (TOC), has been described as being, first and foremost, a philosopher. The TOC body of knowledge is mainly preserved as concrete methodologies used in the management discipline. By examining the foundational elements of synechism and the TOC, the purpose of this study is to investigate the intellectual connections between the arguments and legacies of Goldratt and Peirce. Although this connection is worthy of much further investigation, the research emphasizes the possible implications from a management philosophy perspective.
Design/methodology/approach
Based on a “review with an attitude,” the authors first examined the foundations of Goldratt’s TOC through the lens of Peirce’s synechism. Next, the authors then examined how the study of Peirce combined with a selection of contemporary research in the management and organizational studies domain could point out a direction toward completing Goldratt’s unfinished intellectual work to establish a unified science management while addressing some of the current gaps in the TOC body of knowledge.
Findings
Major findings show that synechism’s growth may extend TOC knowledge, improving managerial practice in organizations. Findings on the convergent ideas of both also reveal that Goldratt valued all synechism categories, emphasizing the importance of not overlooking Firstness. Furthermore, the study analyzes the abductive inference demonstrated in the two use cases, introducing an additional metaphor to the management of organizational systems inspired by Peirce’s philosophical concepts. The research concludes that incorporating TOC and synechism principles can enhance management and organizational practices and enrich management philosophy and theories.
Research limitations/implications
This pioneering research opens promising opportunities to draw parallels between Peirce and Goldratt. Interdisciplinary collaboration will enhance the rigor and validity of integrating synechism and TOC. Experts in organizational behavior, systems theory and complexity science can provide valuable insights into this debate, while practitioners and consultants could help identify barriers and opportunities for integrating synechistic principles.
Practical implications
The study proposes a novel abductive approach using Peirce’s cable metaphor as an initial framework to build a unified science of management based on evolutionary stages: TOC, common sense and connectedness.
Originality/value
This research reinforces the argument that contemporary management practices need philosophical thinking. The authors argue that re-evaluating the foundations of management thought enriches the decision-making process in organizations and the understanding of contemporary theories in management and organizational studies.
Details
Keywords
This paper explains at least some of the major problems related to the subject indexing process and proposes a new approach to understanding the process, which is ordinarily…
Abstract
This paper explains at least some of the major problems related to the subject indexing process and proposes a new approach to understanding the process, which is ordinarily described as a process that takes a number of steps. The subject is first determined, then it is described in a few sentences and, lastly, the description of the subject is converted into the indexing language. It is argued that this typical approach characteristically lacks an understanding of what the central nature of the process is. Indexing is not a neutral and objective representation of a document’s subject matter but the representation of an interpretation of a document for future use. Semiotics is offered here as a framework for understanding the “interpretative” nature of the subject indexing process. By placing this process within Peirce’s semiotic framework of ideas and terminology, a more detailed description of the process is offered which shows that the uncertainty generally associated with this process is created by the fact that the indexer goes through a number of steps and creates the subject matter of the document during this process. The creation of the subject matter is based on the indexer’s social and cultural context. The paper offers an explanation of what occurs in the indexing process and suggests that there is only little certainty to its result.
Details
Keywords
Purpose – To explore lines of inquiry by Hayek and C. S. Peirce on sensation and cognition and Hayek's interest in Peirce.Methodology – To compare Hayek and Peirce's relational…
Abstract
Purpose – To explore lines of inquiry by Hayek and C. S. Peirce on sensation and cognition and Hayek's interest in Peirce.
Methodology – To compare Hayek and Peirce's relational interpretations of sensation and cognition.
Research limitations – The theories of both Hayek and Peirce on sensation and cognition are more extensive than can be addressed here. This exploration is more suggestive than comprehensive.
Findings – Both Hayek and Peirce emphasized the relational and abstract nature of human mental processes. Hayek viewed his contribution as overlapping with psychology while Peirce viewed his theory as being logically before psychology.
Social implications – The ideas of Peirce and Hayek imply that the traditional empiricist and rationalist epistemologies of cognition and sensation are limited and incomplete and thus embrace cognitive inefficiencies.
Originality/value of paper – Hayek's brief references and interest in the ideas of C. S. Peirce have not yet been explored to date.
Details
Keywords
Presents the scientific methodology from the enlarged cybernetical perspective that recognizes the anisotropy of time, the probabilistic character of natural laws, and the entry…
Abstract
Presents the scientific methodology from the enlarged cybernetical perspective that recognizes the anisotropy of time, the probabilistic character of natural laws, and the entry that the incomplete determinism in Nature opens to the occurrence of innovation, growth, organization, teleology communication, control, contest and freedom. The new tier to the methodological edifice that cybernetics provides stands on the earlier tiers, which go back to the Ionians (c. 500 BC). However, the new insights reveal flaws in the earlier tiers, and their removal strengthens the entire edifice. The new concepts of teleological activity and contest allow the clear demarcation of the military sciences as those whose subject matter is teleological activity involving contest. The paramount question “what ought to be done”, outside the empirical realm, is embraced by the scientific methodology. It also embraces the cognitive sciences that ask how the human mind is able to discover, and how the sequence of discoveries might converge to a true description of reality.
Details
Keywords
Current research methodologies in the field of information science employ induction or deduction, ignoring the third fundamental mode of cognition, retroduction. This paper seeks…
Abstract
Purpose
Current research methodologies in the field of information science employ induction or deduction, ignoring the third fundamental mode of cognition, retroduction. This paper seeks to introduce the Retroductive Recognition of Absence (RRA) methodology that expands inquiry from its current inductive and deductive bases to include the intuition‐based retroduction/abduction of Charles Sanders Peirce.
Design/methodology/approach
In brief, RRA consists of an iterative performance, of its nine‐step heuristic, with each iteration narrowing the scope of the research, while increasing the depth of examination. The nine steps are: perceive a phenomenon leading to surprise; perform the fundamental and primary retroduction; synthesize the phenomenon into a hypothesis; bracket intuitive prejudices; immerse in the data; conceptualize; hypothesize; select the hypothesis most efficient to test; and test the hypothesis. The iterations continue until the researcher reaches a hypothesis testable by inductive or deductive methods. This RRA methodology incorporates a “definition heuristic” that defines any previously undefined concept, a heuristic based on Spradley and McCurdy's classification of definitions.
Findings
A study of Compelled Nonuse of Information (CNI) demonstrated the usefulness of RRA in the study of phenomena from an initial “hunch” to a testable hypothesis. As such, the RRA methodology decreases subjectivity and imparts rigor to the study of absent or newly emergent phenomena that have no theoretical basis, no data, and no pre‐existing, coherent body of literature.
Originality/value
This paper presents the philosophy and practice of the RRA methodology and the retroductive philosophical inquiry postulated by Peirce.
Details
Keywords
H. Sekhar and R. Mahanti
The aim of the research is to use an integrated approach – simulation and Six Sigma to improve the ambient air quality.
Abstract
Purpose
The aim of the research is to use an integrated approach – simulation and Six Sigma to improve the ambient air quality.
Design/methodology/approach
Integration of simulation and Six Sigma DMAIC methodology in a foundry had been used to improve the ambient air quality. Various elements of the Six Sigma toolkit such as Cause and Effect diagrams and Failure Mode and Effect Analysis have been used to discover the root causes underlying the problem and prioritize action and incorporate cost‐effective solutions. Simulation has been used to improve and control the environmental efficiency by monitoring the performance of the Venturi Scrubber – the pollution control equipment, by running the model under varying conditions.
Findings
The integrated application of Six Sigma and simulation has been successful in reducing particulate emissions from 200 milligrams per cubic meter to less than 20 milligrams per cubic meter and sulphur dioxide emissions from 45 milligrams per cubic meter to less than 4.5 milligrams per cubic meter, thus reducing air pollution.
Practical implications
Air pollution is a burning problem in the present scenario and foundry industries are one of the contributors to air quality degradation. The approach described in this paper is a step towards reducing air pollution due to foundry operations.
Originality/value
Integration of Six Sigma DMAIC methodology and simulation provides a novel cost‐effective strategy for monitoring and reducing air pollution resulting from foundry operations. This paper is useful for environmental division of foundry and other manufacturing industries.