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We consider an oriented network of activities characterized by activity times. Applying the theory of relatively closed systems, the network nodes are interpreted as elements and completion times as element outputs. The behavioural relation of each element is written algebraically in operator form. It is shown how the behavioural relation of the system as a whole may be solved in such a way that explicit dependencies of all completion times on the given activity times are obtained. In this process a matrix containing maximum operators is inverted and the operators in the inverse matrix retain their interpretation.

The theory of relatively closed systems first appeared in Kybernetes as two consecutive papers by Grubbström This work was a development of studies in cybernetic modelling performed by Lange and Klir and Valach. This paper deals with an application taken from the field of inventory control. The purpose is to show how the theory of relatively closed systems can be used to formulate models, analyse stability conditions and compute equilibrium values for the variables involved.

Argues that the Hempel‐Oppenheimian logical scheme for explanations and predictions also applies to prescriptive statements (recommendations) derived from theoretical models in the normative sciences. Presents ideas concerning the allocation of effort in developing normative models for such purposes. Three characteristics of the model and the model‐building process, together with a suggested qualitative relationship between these properties, are discussed, namely the “applicability” of the model, the “simplicity” of the principle derived from the model, and the “level of technique” applied, a discussion similar to that of Bronfenbrenner. It is proposed that the subjective value to the model‐builder may be envisaged as a function of these three main characteristics and that the model‐design process then may be interpreted as a constrained optimisation problem.

The paper provides an overview of research published in the innovation and operations management (IOM) literature on 15 methods for cost management in new product development, and it provides a comparison to an earlier review of the management accounting (MA) literature (Wouters & Morales, 2014).

This structured literature search covers papers published in 23 journals in IOM in the period 1990–2014.

The search yielded a sample of 208 unique papers with 275 results (one paper could refer to multiple cost management methods). The top 3 methods are modular design, component commonality, and product platforms, with 115 results (42%) together. In the MA literature, these three methods accounted for 29%, but target costing was the most researched cost management method by far (26%). Simulation is the most frequently used research method in the IOM literature, whereas this was averagely used in the MA literature; qualitative studies were the most frequently used research method in the MA literature, whereas this was averagely used in the IOM literature. We found a lot of papers presenting practical approaches or decision models as a further development of a particular cost management method, which is a clear difference from the MA literature.

This review focused on the same cost management methods, and future research could also consider other cost management methods which are likely to be more important in the IOM literature compared to the MA literature. Future research could also investigate innovative cost management practices in more detail through longitudinal case studies.

This review of research on methods for cost management published outside the MA literature provides an overview for MA researchers. It highlights key differences between both literatures in their research of the same cost management methods.

To consider aspects of a theory of systemic construction by discussing two concepts which will assist in our understanding of the surrounding world which it is considered is made of both systemic and non‐systemic entities.

Considers how these entities (metasystem, network, transitron etc.) can be conceived and defined. Systemic frames notions are presented and examples of systems given. Discusses the historic use of the word “system” and systemic thinking and its varieties.

Discovered that on the basis of these concepts, an understanding of the surrounding world can be achieved which is not homogeneous but made of both systemic and non‐systemic entities. These can change when certain systemic properties are reached as well as in their specific degrees in their limitations and paradoxes.

Introduces an original approach to the life support system by proposing concepts that are discussed and defined and that will provide cyberneticians and systemists with a revised view of systemic thinking.

This paper sets out to describe transform methods to control vendor‐managed inventory (VMI). It aims to examine the limits of modelling approaches within control‐theoretic models.

Modelling was achieved with the Simulink package using the equations developed by Disney and Towill for a two‐tier VMI system. Discrete and continuous models were considered together with two forms of production delays: a finite delay and the Forrester exponential delay. Standard control engineering analyses of these delay representations were compared to illustrate how the system response and stability depend on their formulation and to determine the permissible gains.

Response by a discrete or continuous model to step inputs in sales rates depends on the type of delay representation but the responses do not differ by more than 5 per cent if the same delay form is used in the models. The prime effect of using a finite delay is to deepen the stock‐out and increase the required order rate compared with the same response observed with the use of exponential forms of delay. Total time for recovery is similar with all models. It is shown that the continuous model with an exponential delay is always stable and when using a fixed delay the continuous model can be made stable.

The models presented here illustrate that the various forms of control‐theoretic models present similar results irrespective of technique used, provided that they have the same delay type. The range of gains for the required order rate can be computed for any VMI system, knowing that they can be designed to guarantee stable operation.

This work extends that of Disney and Towill to include different modelling representations. It allows operational gains to be safely chosen for stable operation.

Environmental communication has been a profession and a subject of study for decades. Communication currently revolves around the anthropogenic ecological catastrophe, which makes the field’s early self-description as a crisis discipline even more pertinent. How communication is used and perceived significantly impacts how human-caused climate disasters and other environmental and social problems develop and how solutions are offered. The phenomenon of technology has shown significant impacts on how people refer to environmental communication. While bibliometric analysis (BA) helps understand the trends, ChatGPT can generate information related to environmental communication. How are they different from each other? What are the limitations? This study aims to identify the trends and limitations of BA and ChatGPT that are associated with environmental communication.

A qualitative approach is used, which refers to BA using the Biblioshiny software (n = 867) and content analysis on ChatGPT 3.5. It uses a systematic technique for keyword search, namely, environmental and communication, from 2000 to 2022.

There has been a decrease in the scientific production of studies starting in 2021 and 2022, which is believed to be due to the COVID-19 pandemic. ChatGPT provides valuable information but is rather complimentary to BA. ChatGPT is unable to provide statistical information related to environmental communication among Scopus-indexed publications.

This study focuses on the literature published in Scopus from 2000 to 2022. The keyword is limited to “environmental” and “communication.” Besides, the choice of keywords made it specific to the studies involved in the BA, which may not include some other studies if the keywords are not listed.

The originality of the research focuses on the field of environmental communication, its evolution within previous literature and the comparison between BA and the use of ChatGPT for understanding trends and limitations within this field. The text touches upon various aspects, such as the historical context of environmental communication, the impact of technology, the trends in scientific production among Scopus journal papers and the limitations of using ChatGPT compared to BA.