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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.

I survey applications of Markov switching models to the asset pricing and portfolio choice literatures. In particular, I discuss the potential that Markov switching models have to fit financial time series and at the same time provide powerful tools to test hypotheses formulated in the light of financial theories, and to generate positive economic value, as measured by risk-adjusted performances, in dynamic asset allocation applications. The chapter also reviews the role of Markov switching dynamics in modern asset pricing models in which the no-arbitrage principle is used to characterize the properties of the fundamental pricing measure in the presence of regimes.

This paper aims to present a continuous-time workforce planning model in which workforce flow occurs in terms of internal and external recruitment considering human resource strategies (HRS). The proposed model is a linear optimal control model in which promotions occur by inside appointment and outside employment of the system considering a cost leadership or a differentiation strategy and whether organizations have an internal or an external recruitment orientation. In other words, in the model and its solution procedure, this paper could determine any arbitrary function for the demand of the workforce with each HRS.

The proposed model contains five main sections, namely, applicants, newcomers, workforce who are doing sensitive-simple jobs, expert workforce and supervisors (or managers) that have a different orientation in different HRS. Each of these sections has a target value that this paper tries to attain it by applying appropriate control variables, such as recruitment, layoff, degradation, promotion and retirement. To reach this purpose, this paper formulated an optimal control problem using a linear system transition equation with a quadratic cost function.

Based on the proposed model, it was found that the optimal control model can interpret the managerial aspects. This model could be useful for different firms with different types of workforce demands. This paper has tried to have a comprehensive view of different flows of the workforce in an organization that concern to workforce planning.

Despite the considerable amount of research published, and the importance of following a human resources strategy from organizational strategy, in the knowledge, there is no comprehensive study dedicated to human resources strategy and workforce planning by optimal control models for workforce planning.

Marksmanship data is a staple of military and law enforcement evaluations. This ubiquitous nature creates a critical need to use all relevant information and to convey outcomes in a meaningful way for the end users. The purpose of this study is to demonstrate how simple simulation techniques can improve interpretations of marksmanship data.

This study uses three simulations to demonstrate the advantages of small arms combat modeling, including (1) the benefits of incorporating a Markov Chain into Monte Carlo shooting simulations; (2) how small arms combat modeling is superior to point-based evaluations; and (3) why continuous-time chains better capture performance than discrete-time chains.

The proposed method reduces ambiguity in low-accuracy scenarios while also incorporating a more holistic view of performance as outcomes simultaneously incorporate speed and accuracy rather than holding one constant.

This process determines the probability of winning an engagement against a given opponent while circumventing arbitrary discussions of speed and accuracy trade-offs. Someone wins 70% of combat engagements against a given opponent rather than scoring 15 more points. Moreover, risk exposure is quantified by determining the likely casualties suffered to achieve victory. This combination makes the practical consequences of human performance differences tangible to the end users. Taken together, this approach advances the operations research analyses of squad-level combat engagements.

For more than a century, marksmanship evaluations have used point-based systems to classify shooters. However, these scoring methods were developed for competitive integrity rather than lethality as points do not adequately capture combat capabilities. The proposed method thus represents a major shift in the marksmanship scoring paradigm.

The purpose of this paper is to analyze the reliability of the quantitative risk model used for planning inspection and maintenance activities. The objective is to critically discuss the factors that contribute to the probability and consequence of failure calculations.

The case study conducted using one of the most widely deployed risk models in the oil and gas industry where a full assessment was performed on an offshore gas producing platform.

The generic failure frequencies used as the basis for calculating the probability of failure are set at a value representative of the refining and petrochemical industry's failure data. This failure database does not cover offshore. The critical discussion indicated the lack of basis of the coefficient of variances, prior probabilities and conditional probabilities. Moreover, the risk model does not address the distribution of thickness measurements, corrosion rates and inspection effectiveness, whereas only overall deterministic values are used; this requires judgment to determine these values. Probabilities of ignition, probabilities of delayed ignition and other probabilities in Level 1 event tree are found selected based on expert judgment for each of the reference fluids and release types (i.e. continuous or instantaneous). These probabilities are constant and independent of the release rate or mass and lack of constructed model. Defining the release type is critical in the consequence of the failure methodology, whereas the calculated consequences differ greatly depending on the type of release, i.e. continuous or instantaneous. The assessment results show that both criteria of defining the type of release, i.e. continuous or instantaneous, do not affect the calculations of flammable consequences when the auto-ignition likely is zero at the storage temperature. While, the difference in the resulted toxic consequence was more than 31 times between the two criteria of defining the type of release.

There is a need to revamp this quantitative risk model to minimize the subjectivity in the risk calculation and to address the unique design features of offshore platforms.

This case study critically discuss the risk model being widely applied in the O&G industry and demonstrates to the end-users the subjectivity in the risk results. Hence, be vigilant when establishing the risk tolerance/target for the purpose of inspection and maintenance planning.

Deals with the formulation and application of temporal and spatial spectral element approximations for the solution of convection‐diffusion problems. Proposes a new high‐order splitting space‐time spectral element method which exploits space‐time discontinuous Galerkin for the first hyperbolic substep and space continuous‐time discontinuous Galerkin for the second parabolic substep. Analyses this method and presents its characteristics in terms of accuracy and stability. Also investigates a subcycling technique, in which several hyperbolic substeps are taken for each parabolic substep; a technique which enables fast, cost‐effective time integration with little loss of accuracy. Demonstrates, by a numerical comparison with other coupled and splitting space‐time spectral element methods, that the proposed method exhibits significant improvements in accuracy, stability and computational efficiency, which suggests that this method is a potential alternative to existing schemes. Describes several areas for future research.

Unobtrusive measurement methodologies are critical to implementing intelligent tutoring systems (ITS) for teams. Such methodologies allow for continuous measurement of team states and processes while avoiding disruption of mission or training performance, and do not rely on post hoc feedback (including for the aggregation of data into measures or to develop insights from these real-time metrics). This chapter summarizes advances in unobtrusive measurement developed within Army research programs to illustrate the variety and potential that unobtrusive measurement approaches can provide for building ITS for teams. Challenges regarding the real-time aggregation of data and applications to current and future ITS for teams are also discussed.

Worldwide, companies are interested in improving processes and reaching high levels of quality through the adoption of various systems. For example, they implement quality management methodologies, such as Lean, with the aim of reducing waste and cost. In the food sector, however, companies also adopt food safety management systems, such as BRC (British Retail Consortium), destined to comply with the standards of hygiene, food safety and quality systems. Interestingly, both Lean and BRC seek to boost quality. Thus, both should be able to work as a single system and cooperate to add value to a company without duplicating efforts. By solving the problems in the bag sealing process of an Ecuadorian company through the implementation of Lean tools incorporated in the steps of the DMAIC methodology (define-measure-analyze-improve-control), and then framing a cooperation matrix of Lean tools and BRC clauses, this paper seeks to demonstrate their feasible cooperation.

One of the most well-known methodologies for process improvement is the DMAIC methodology. Through the sequence of the DMAIC steps, the main problem of an Ecuadorian company that produces flexible packaging for food was identified. With the voice of the customer (VOC) from historical customer surveys of the company, the common issues were found. Similarly, historical data of non-conformities required by ISO-9001: 2015 provided insightful information for this phase. In order to measure the current quantitative state of the processes, a VSM (value stream map) was jointly employed with an operator balance chart. Data was collected during the whole operational month. Having this quantitative data, and with the ideas generated from the Kaizen events, improvement initiatives were analyzed and proposed. The proposed solutions involve production and maintenance teams. After some tests, it was verified that all these improvements had had a positive impact on the company. Finally, it was analyzed that Lean tools can collaborate and also be used as proof for BRC requirements. Thus, a correlation matrix between them was built, which demonstrates cooperation between both systems.

The results of this study indicate that Lean can cooperate in the pursuit of the BRC Standard for food packaging companies. This is shown through the case study of the Ecuadorian company, which implemented Lean tools and reduced its costs by shortening lost time and reducing set up time in the machines employed to cut and seal bags. Additionally, overall equipment effectiveness (OEE) from machines 1 and 2 rose their values considerably. Since BRC is a certifiable standard, it contains clauses that must be achieved in order to get the certification. By using Lean tools, it was possible to comply with some of the clauses of the BRC standard. A matrix was built so that it could be identified that Lean tools can work together with BRC, and thus, reduce costs and waste, while simultaneously complying with the safety and quality standards that the standard guarantees.

This research had two limitations. The first limitation is related to time. The data was collected in a month due to the project's deadline. For further research, it is recommended to increase this period of time to at least three months of production. The second limitation is related to the processes studied, which are associated with the time period. This study encompasses two major processes, which present major problems. For further investigations, longer periods of time can allow to include more processes from the company.

The implications of this project rely on the fact that the company achieved a better level of efficiency. The application of Lean tools reduces waste in the company. Basically, the waste was associated with lost time in machines 1 and 2 from the cutting and sealing processes, which was mainly produced by mechanical malfunction and inefficient maintenance. These problems had a direct relationship with the bad quality of the bags since the machines operate almost fully automatically. Additionally, mechanical problems caused by inefficient maintenance have a direct impact on quality aspects of the bag, like correct dimensions or a proper seal. Moreover, these problems generate a loss of time since the operator must stop the machine during production time in order to fix it. Machines 1 and 2 reduced their lost time drastically. Furthermore, by using Lean tools alongside the BRC methodology, the company can now reduce the resources that are destined for Lean projects and the BRC certification. Specifically, as a result, Lean tools and their documents can serve as proof of compliance with certain BRC clauses.

These improvements impact the company's profits, and therefore the workers. Since there is a significant reduction in the company's costs, and also an increment in the company's production, the company will probably require hiring new employees. In this way, more job opportunities will be generated.

The originality of this work relies on the nature of the research and the type of production facility. Previous studies have examined Lean tool applications in many settings. There are a few studies regarding the adoption of BRC standards. However, and definitely, the merge between Lean tools and a food safety management system is novel, since there are few to almost no articles that have been published using such a merge. The positive outcomes that were obtained not only prove that both methodologies are compatible, but they can also encourage further research on the applicability and functionality of merging two methodologies similar to the ones used during this research. Regarding the production facility, very few articles have been published about flexible packaging companies, and this article will help further research in this field.

New ways of managing change have run aground on the uncritical acceptance of a limited view of temporality, identified here as causal-time. Because it emphasizes identity and state-transitions, causal-time is inherently static and past-centered. An alternative view, called flow-time, emphasizes the dynamic of the always arriving future. The claim is made that a future-centered temporality gives access to the knowledge change agents need to cope with accelerating and ongoing change.