This special issue of Production Planning & Control is devoted to complex systems analysis, modelling and simulation. Complex systems analysis is an interdisciplinary field. Presented articles focus on systems analysis and systems theory, modelling and simulation, decision support systems, modelling and simulation of complex organisations and control and execution systems. Topics treated in this special issue are interesting both for academics and practitioners. These topics are applications concerning manufacturing systems and healthcare systems.
The article, ‘Reorganising a service department: Central Patient Transportation’ by Naesens et al. provides an analysis of the operations at the service department ‘Central Patient Transportation’ at the University Hospital Gasthuisberg, Leuven, Belgium. Their analysis generates several suggestions for improvement. Their recommendations are based upon observations, questionnaires, in-depth interviews and analysis of historical data. The authors observed that the perception of long waiting times (for transportation), both in the medical examination departments and in the nursing departments result in a need for improvement (and even reengineering) of the service department. However, Naesens et al. observed that some problems are situated in people management skills. The number of operators (currently 77) seems to be insufficient to handle the growing number of requests for transportation (currently more than 1200 transports per day on average). The rate of absenteeism among operators is relatively high, and supervision is very difficult due to the lack of appropriate control mechanisms. The authors also identified some organisational and infrastructural problems. They remarked the need for improvement of the planning process. For example, the ‘pick to light’ system to transport the patients from the medical department to the nursing units seems outdated. Furthermore, the high failure rate of the elevators causes major disturbances in the transportation process. This analysis indicated that there is an urgent need for restructuring the transportation services. A fundamental reengineering of the process has been suggested, namely a partial decentralisation of the transportation services. Analysis indicated that after implementation of partial decentralisation, many of the above-mentioned problems seem to be solved. Consequently, the quality perception of the transportation service and therefore the overall quality perception of the university hospital should increase.
Wang et al.'s article is titled ‘Modelling and simulation of emergency services with ARIS and Arena’ and deals with overlong waiting time in emergency services. Overlong waiting times have negative influence on healthcare quality. Using modelling and discrete event simulation of system process, the authors show that this problem can be solved and emergency services can be improved. The simulation model of Wang et al. is designed to represent the patient visit process by using ARIS and Arena, respectively. This simulation model helps to identify process bottlenecks, and adjust resources allocation or staff dimensioning without disturbing the actual system. For the purpose of reducing waiting time in emergency departments, Doctor's efficiency improvement and Quick Pass process are proposed and experimented as two new solutions. In addition to simulation results, they present some advantages and shortcomings observed during their development work for future use of ARIS and Arena. Their work was based on the Emergency Department at Saint Joseph and Saint Luc Hospitals in Lyon, France.
The article ‘A structured modelling approach to simulating dynamic behaviours in complex organisations’ by Zhen et al. reports a case study application of a systematic approach to modelling complex organisation centred on simulation modelling. The approach leads to populated instances of complementary model types. These models systematically capture, validate and facilitate various uses of organisational understandings, knowledge and data normally distributed amongst multiple knowledge holders. The model driven approach to decision making enables improved manufacturing responsiveness. An enterprise modelling example of a capacitor manufacturing company is described as a derivative causal loop that structure and enable the design and the use of a general purpose simulation model.
‘Design and validation of product driven control system based on six-sigma methodology and discrete event simulation’ is the article by El Haouzi et al. The research focuses on the feasibility of the product-driven concept. The concept is evaluated by the development of an industrial test-bed from Trane Company (France) using an approach based on six-sigma methodology. Requirements for manufacturing control evolve from traditional centralised approaches where decision making is hierarchically broadcasted to more complex distributed control architectures. Product Driven system has been suggested as a concept for these future manufacturing systems. This concept advocates that the product can be an active actor throughout its life cycle. Nowadays, this concept is technically feasible using some new technologies as RFID. However, the lack of a complete and unified RFID standard and the high cost of their infrastructure have discouraged many companies from adopting this technology. Numerous efforts are being made to bridge this gap, but the pertinence of such implementation project remains too difficult to justify. El Haouzi et al.'s main results show benefits for product traceability, cost and time reduction resulting in a better synchronisation and anticipation between the manufacturing, assembly and supplying lines of the Trane plant.
Since the mid-1990s, Manufacturing Execution Systems (MES) have significantly evolved into more powerful and integrated software applications as computing technologies have advanced. MES functionality coverage has changed significantly and can now provide a common and single system to support most of the manufacturing execution processes from the production order release to the delivery of finished goods. Nonetheless, MES applications still fall short of adding capabilities for decision-making tools in very dynamic organisations where adaptive execution strategies are required to replenish the supply chain while dynamically responding to unpredicted change. The article ‘Manufacturing execution system – a literature review’ by Saenz de Ugarte et al. intends to describe what MES have become, present the relationships of MES with other enterprise information systems and identify major issues related to MES. The authors also discuss research areas that need to be explored in order to resolve the increased complexity of execution systems and to fulfil the continuing customer needs for faster real-time response and expanded functionality coverage.
Acknowledgements
The guest editors would like to thank all the authors for their contributions, and the reviewers for their dedication and timely feedback provided to contributing authors of this special issue. The administrative work of Maryline Goudalier and Anne-Lise Pieders to accomplish this special issue is very much appreciated; their diligence is commendable. They deserve our sincere thanks and respect for their continuous collaboration.