The consequences of time-phased order releases on two M/M/1 queues in series.

A key characteristic of MRP applications includes the coordination of assembly and purchased component requirements by time-phased order releases. In the literature on order review and release strategies, time- phased order releases are described as a worthy alternative to load limited release mechanisms. This paper initializes the development of a stochastic model that quantifies the consequences of time-phased order releases on the stochastic system behavior. This is done by introducing them in an open queueing network composed of two M/M/1 stations. The core of the analysis is focused on the modified flow variability which is specified by the second-order stationary departure process at the first station in the routing. It is a process characterized by a negligible autocorrelation. Based on the stationary-interval method and the asymptotic method, we propose an approximating renewal process for the modified departure process. The modelling efforts provide interesting conclusions and practical insights on some coordination issues in stochastic multi-echelon systems.

Evaluating concepts for short-term control in financial service processes

Financial services are characterised by the integration of customers while the service is being delivered. This integration leads to interruptions and thus delays in the processing of a customer order until for example the customer provides the missing input. Because customer behaviour can only be planned to a certain extent this is a major problem for an efficient control of financial service processes. It would be helpful to know which concept leads to the best solution for a certain situation in controlling the process. A concept contains explicit practical knowledge e.g. using a stand-by-employee or a prioritisation of customer orders with first-infirst-out. As financial services differ from manufacturing processes application knowledge of concepts cannot be transferred one to one. To test concepts regarding their ability to deal efficiently with interruptions by customers short-term simulations should be conducted. Shortterm simulation uses the actual state of a process and is not focussing on steady-state results. The research presented focuses on comparing several concepts for short-term control using case-study data of a typical financial service process. For this process a simulation model is built based on process mining. This approach is used to gather information out of documented timestamps of underlying process-aware information systems. Such timestamps allow a historical analysis to build typical scenarios and to gather the actual state of a financial service process as a starting point for a simulation analysis. The depicted concepts are simulated for different typical scenarios points to determine respectively which concept suits best. The results show which concepts suit best in certain situations for the case study conducted. --short-term control,financial services,business process simulation

From ERP to advanced resource planning: Improving the operational performance by getting the inputs right.

In this paper, we show that the planning and decision support capabilities of the MPC (Manufacturing Planning and Control) system, which forms the core of any ERP package, may be greatly enhanced by including an Advanced Resource Planning (ARP) module as an add-on at the midterm planning level. This ARP module enables to estimate the impact of variability, complexity and dynamic system behavior on key planning parameters. As such, it yields realistic information both for short-term planning purposes and for reliable lead time quotations. We show how dynamic behavior impacts the operational performance of a manufacturing system, and discuss the framework for incorporating the ARP module into the ERP system.Planning; Operational performance; Performance; International; Science;

Advanced resource planning as decision support module to ERP.

In this paper, we show that the planning and decision-support capabilities of the MPC (Manufacturing Planning and Control) system, which forms the core of any ERP (Enterprise Resource Planning) package, may be substantively enhanced by including a Decision Support Module (DSM) as an add-on at the midterm planning level. This DSM, called Advanced Resource Planning (ARP), serves as parameter setting process as well as tool for improving the structure of the ERP system itself. The ultimate goal of the DSM is to yield realistic information both for scheduling, sales and marketing, strategic and operational decision making and suppliers and customers.

LOGISTICS AND SUPPLY CHAIN STRATEGIES IN GRAIN EXPORTING

During the past decade, the grain shipping industry has become highly competitive and technologically advanced. These changes, along with the introduction of innovative shipping mechanisms, have made logistics management an important source of opportunity and risk for grain shippers. In this study, a stochastic simulation model was developed to evaluate the tradeoffs and effects of key variables on logistical performance in managing the grain supply chain. Average demurrage cost for the supply chain was $2.03 million with the greatest cost being for railcars and the least cost being for barges. Of the stochastic variables modeled, changes in export demand had the greatest impact on demurrage costs.Supply Chain, Grain Shipping, Logistics, Demurrage, Guaranteed Freight, Industrial Organization,

Managing design variety, process variety and engineering change: a case study of two capital good firms

Many capital good firms deliver products that are not strictly one-off, but instead share a certain degree of similarity with other deliveries. In the delivery of the product, they aim to balance stability and variety in their product design and processes. The issue of engineering change plays an important in how they manage to do so. Our aim is to gain more understanding into how capital good firms manage engineering change, design variety and process variety, and into the role of the product delivery strategies they thereby use. Product delivery strategies are defined as the type of engineering work that is done independent of an order and the specification freedom the customer has in the remaining part of the design. Based on the within-case and cross-case analysis of two capital good firms several mechanisms for managing engineering change, design variety and process variety are distilled. It was found that there exist different ways of (1) managing generic design information, (2) isolating large engineering changes, (3) managing process variety, (4) designing and executing engineering change processes. Together with different product delivery strategies these mechanisms can be placed within an archetypes framework of engineering change management. On one side of the spectrum capital good firms operate according to open product delivery strategies, have some practices in place to investigate design reuse potential, isolate discontinuous engineering changes into the first deliveries of the product, employ ‘probe and learn’ process management principles in order to allow evolving insights to be accurately executed and have informal engineering change processes. On the other side of the spectrum capital good firms operate according to a closed product delivery strategy, focus on prevention of engineering changes based on design standards, need no isolation mechanisms for discontinuous engineering changes, have formal process management practices in place and make use of closed and formal engineering change procedures. The framework should help managers to (1) analyze existing configurations of product delivery strategies, product and process designs and engineering change management and (2) reconfigure any of these elements according to a ‘misfit’ derived from the framework. Since this is one of the few in-depth empirical studies into engineering change management in the capital good sector, our work adds to the understanding on the various ways in which engineering change can be dealt with

SLA-Oriented Resource Provisioning for Cloud Computing: Challenges, Architecture, and Solutions

Cloud computing systems promise to offer subscription-oriented, enterprise-quality computing services to users worldwide. With the increased demand for delivering services to a large number of users, they need to offer differentiated services to users and meet their quality expectations. Existing resource management systems in data centers are yet to support Service Level Agreement (SLA)-oriented resource allocation, and thus need to be enhanced to realize cloud computing and utility computing. In addition, no work has been done to collectively incorporate customer-driven service management, computational risk management, and autonomic resource management into a market-based resource management system to target the rapidly changing enterprise requirements of Cloud computing. This paper presents vision, challenges, and architectural elements of SLA-oriented resource management. The proposed architecture supports integration of marketbased provisioning policies and virtualisation technologies for flexible allocation of resources to applications. The performance results obtained from our working prototype system shows the feasibility and effectiveness of SLA-based resource provisioning in Clouds.Comment: 10 pages, 7 figures, Conference Keynote Paper: 2011 IEEE International Conference on Cloud and Service Computing (CSC 2011, IEEE Press, USA), Hong Kong, China, December 12-14, 201

Priority allocation decisions in large scale MTO/MTS multi-product manufacturing systems : Technical report

In this paper, the authors consider a single stage multi-product manufacturing facility producing a large number of end-products for delivery within a service constraint for the customer lead-time. The manufacturing facility is modeled as a multi-product, multi-priority queuing system. In order to reduce inventory costs, an e±cient priority allocation between items consists in producing some items according to a Make-To-Stock (MTS) policy and others according to a Make-To-Order (MTO)policy epending on their features (costs, required lead-time, demand rates). The authors propose a general optimization procedure that gives a near-optimal °ow control (MTO or MTS) to associate with each product and the corresponding near-optimal priority strategy. We illustrate e±ciency of our procedure via several examples and by a numerical analysis. In addition, we show numerically that a small number of priority classes is su±cient to obtain near-optimal performances.Make-to-Stock (MTS); Make-to-Order (MTO); Priority allocation; Scheduling rule; Heterogeneous multi-product queuing system

Decision support for build-to-order supply chain management through multiobjective optimization

This paper aims to identify the gaps in decision-making support based on multiobjective optimization for build-to-order supply chain management (BTOSCM). To this end, it reviews the literature available on modelling build-to-order supply chains (BTO-SC) with the focus on adopting multiobjective optimization (MOO) techniques as a decision support tool. The literature has been classified based on the nature of the decisions in different part of the supply chain, and the key decision areas across a typical BTO-SC are discussed in detail. Available software packages suitable for supporting decision making in BTO supply chains are also identified and their related solutions are outlined. The gap between the modelling and optimization techniques developed in the literature and the decision support needed in practice are highlighted and future research directions to better exploit the decision support capabilities of MOO are proposed

Towards a collaborative MRP for supply chain coordination

The necessity to increase collaboration in nowadays supply chains is emphasized both by academics and practitioners, but most of the supply chains are still managed through cascades of classical MRP/MRP2 systems. Interviews in the aeronautical sector have shown us the existence of many hidden practices aiming at satisfying local constraints which would be better addressed through collaborative processes. We suggest in this communication to define a "collaborative MRP" which would not only provide a better global performance than purely local planning, but take into account the autonomy of the involved partners which is not always respected by centralized pproaches using APS (Advanced Planning Systems)