System Thinking and Management Modelling - Example

SYSTEM THINKING AND MANAGEMENT MODELLING NAME: STUDENT NUMBER: SUBMISSION DATE: NUMBERED PAGES: 1. Introduction: In recent years, increase in population has been exponential. This has necessitated an increase in construction to cater for homes for the increased number of people as well as business premises as more and more people go into business. Increase of construction wastes is a natural corollary to the increase in construction activity and a huge amount of these wastes are being generated. These wastes represent not only a loss in resources; they also increase the costs of construction and are a threat to the environment. Moreover, the problem of dealing with the wastes takes a lot time that would otherwise be used in activities related directly to construction this is because construction workers prepare half of the total man hours in construction work preparing the materials required in actual construction and the other half removing the wastes generated for disposal. The average labour cost incurred towards the disposal of wastes generated during construction of 100 houses is USD 50000. Increased concern on lack of landfill sites and the health hazards posed by disposal of such wastes is expected to continue driving the costs of disposal up. While increased efficiency and skills on the part of the builders have a big role to play when it comes to taming the problem. There are other players who have either a direct or indirect contribution on the matter of construction waste, (Telford, 1995). This problem can only be effectively handled through the development of a workable plan to manage the wastes by way of reduction and/or recycling. This research is meant to meet the need to develop methodological tools through which decision making on matters of construction site waste management would be made easy by helping the decision makers to know when to recycle, when to reduce and when to combine the two approaches for maximum impact. The study targets management of onsite construction and demolition wastes based on how the wastes in question are generated and how they can be reduced efficiently. System Dynamics (SD) methodology has been employed as the basic modelling and analysis method for the analysis conducted. While the study did not exhaust all possible solutions to the problem, it shows how parties, relevant to the problem are related and from this point of understanding recommends ways that may help in the reduction of construction wastes before taking them to landfill sites. 2. The Problem: The general definition of waste is material that has been used but is no longer wanted, probably because the useful part has been taken out. It also means material that was not used, though it could have been used, in this instance, waste is usually as a result of human error or carelessness. The European Commission Framework Directive provides a more encompassing definition of waste which is more applicable to the question at hand. The framework defines waste as “any material where the holder has an intention to discard the material as no longer part of the normal commercial cycle or chain of utility”. In construction; “ solid waste generated from equipments and materials used in construction activities, demolition, construction development, repair, demolition of structures and buildings, roads, bridges, cleaning the land, the establishment of sewage and renovation. That the residues at the sites include: Asphalt, Plastic, Concrete, Bricks, Wood, Glass, Aluminium, Iron, paint containers, boiler pipe insulation, wires, ceiling’s materials and other materials.” The residual material differs between different construction sites, but benefits accrued from reduction, reuse and recycling cut across the board and they are all equally valuable. In order for this problem to be tackled using the SD approach, Rodriguez & Paucar (2004), listed the steps to be followed; as understanding the issue by defining and analysing it. Conceptualising the model and using the findings thereof to run a simulation model 2.1 problem analysis: To analyse the problem, the following questions should be asked concerning the waste; The figure below is a rich picture representation of the answers for the questions that lead to a proper analysis of the problem The questions include what the original source is, who the people responsible for waste generation are. What type of waste the waste in question is and where the waste ends up Figure 1: The rich picture To enable a more detailed understanding of the problem, hence make it easier to come up with solutions. The whole scenario as represented in the rich picture will be broken down into smaller parts. Taking into consideration all the players and processes involved at all levels. 2.2 The materials themselves: According to the illustration in the rich picture the materials journey through the process begins at the factories where they are manufactured through the process and the residue ends up in a landfill and sometimes in the recycling plant. The initial problem in the entire pipeline is experienced at the very source of materials, i.e. the factory concerning whether the materials meet specifications for the task for which they are sourced. The issue of poor material quality is always as a result of the materials being unsuitable for use in the design. (Figure 2) When materials are not of the required quality, they have to be treated or replaced and both processes lead to generation of more waste. Workers also have a tendency of being careless when dealing with materials they consider substandard, leading to further waste. Construction materials are also generally packaged sometimes for convenience in handling and also for the creation of an impression of quality. All the covers, eventually, become a part of the wastes generated. (Figure 3). Figure 1 Figure 2 2.3 The management: The problem under review concerns all individuals who work in the construction industry throughout the hierarchy. The management are the decision makers and irrespective of the fact that they do not handle the materials directly, some of their decisions are of considerable consequence concerning the amount of waste generated in the sites they manage. Some of the instances when these decisions can have an impact on decision making include when the owner changes orders and when changes have to be done on the design that had been made initially. The management also provides the manner in which workers should be dealt with which may contribute to the amount of waste generated (figure 4). Figure 3 2.4 The storage: Many of construction materials are very sensitive to the environment in which they are stored. This makes storage of materials an important factor contributing to waste generation or limitation of waste depending on the quality of storage. If, for example, cement is kept in wet conditions, that would lead to a lot of wastage as the cement would be destroyed (Figure 5). Figure 4 2.5 The workers: Workers are the most important people contributing to the issue of waste generation. When workers engaged in a construction project lack the skills to prevent wastage of resources, the level of wastes generated is higher. Highly skilled and careful workers on the other hand can make an immense contribution towards reducing the amount of wastes. Lack of accuracy by less skilled workers is one of the key contributors to waste generation. Apart from being skilled workers should also be loyal and happy, this is because unsatisfied staff regardless of how skilled they are or the lack of change in design and orders are still capable of causing a great deal of wastage. The wastage could be due to workers deliberately destroying materials and it would be impossible for the management to monitor their every move. How the management handles workers is critically important for this reason. Figure 5 2.6 Landfill and recyclers input: Recycling and reusing the waste materials reduces the quantity of waste. The waste that remains after recycling and reusing goes to landfills. Landfills play an important role in reducing the amount of waste as an environmental pollutant. Recycling, reusing and use of landfills, however, do not deal with the main problem of waste generation. Landfills can make a contribution towards reduction of wastes by declining to accept wastes that contain certain materials that could have been reused or recycled or whose waste could have been avoided. That way, the workers and construction managers would be more careful, faced with the possibility of having waste they have nowhere to take. Figure 6 3. Methodological approach SD methodology, which has been used in this paper, is a modelling and imitation technique whose specific design is for long-term, continuous, and non static management problems. It is mainly geared towards understanding the interrelation between processes, flow of information as well as the flow of administrative initiatives towards the formation of variables that are to be considered in the analysis. The combination of the interactions between the different components gives definition of structure of the system, Vlachos et al (2006). It is critical for an SD model show the main “dynamic pattern” of the situation. The reason why this model would be made is, therefore, not to predict the amount of waste that would be generated. Rather it would be to foretell the conditions under which the amount of waste would be least. 3.1 Model Building: SD is different from other methodologies because it tells how the current situation has been arrived at and also show which steps should be taken in order to make improvements. Stock flow diagrams were applied to the situation and as a result, three models were built in order to show the link between problems and variables (Forrester 1992). 3.1.1 Model (1). This model simply describes the process. During the commencement of the project, there is a certain amount of materials that are required to fulfil requirements of the design. When workers use these materials towards achieving the objectives of the design, waste is generated in the process. The waste is either taken to a landfill or it is recycle Figure 7 model (1) 3.1.2 Model (2). Model 2 shows the main connection between variables. It outlines the fundamental relationship between variables. It endeavours to show how project managers may prevent wastage by being thorough at design, thus ensuring no changes will be required, hence the reduction of waste. Managers can also make a point of procuring high quality materials to reduce the need for replacement. Management and supervision of workers handling materials directly is also an important aspect of this model. Figure 8 model (2) 3.1.3 Model (3). The third model portrays the relationships between different parts and how each affects the other. In order for the dynamics in the system and solutions to the problems to be made clear all of the feedback loops will be addressed separately. A thorough, well thought out design would lead to less mistakes which eventually lead to generation of less waste. A skilled management team leads to high quality design makes the customer or the owner satisfied and that leads to less changing orders and less wastes. The management, if it is competent, also ensures that the materials procured are of good quality and they are properly stored in order to prevent wastage. 1) If the staff employed by the management is skilled and can accurately use materials as per design the amount of waste is reduced. Hiring of such skilled staff requires competence on the part of management. 2) The skilled members of staff are capable of handling of materials and equipment without wastage. If the management employs the suitable management methods workers will develop loyalty and feel obligated to handle the materials with care as they are satisfied and feel part of the process. The workers feel they own the project and hence would not deliberately waste materials. When workers feel that they are working with high quality materials, they are likely take more care of it thus reducing wastage. The factory should find a way of packaging that achieves the objective of keeping the materials safe while, at the same time reducing the amount of package waste that will be on site. The government should toughen its stand on matters regarding quantities of waste and take policy measures to encourage reuse and recycle of waste. Figure 9 model (3) This model is a demonstration of how change in one part is likely to have ramifications in the entire system From this model, it is clear that the management style informs the behaviour of workers directly involved with use of materials "Everything is connected to everything else" Sterman, (2001). It shows that how workers are handled by management has a great contribution to the problem The graphs that follow outline the relationship between the main variables and the total amount of wastes. 4. Discussion: Towards coming up with this model, the first step was the identification of the problem. The rich picture was used to provide a base reference for variables and the relationship between them. This was followed by a breakdown of rich picture into different parts to explain how the different parts are related. These steps made it easier to see how the problem has arisen and who the main contributors to the problem are. To begin analyzing the problem and expound on the part played by each of the parties shown in the rich picture, waste was the core object towards which other links moved. Three models were drawn using stock-flow diagrams. The first model was used as a description of the rich picture while the second one included variables which had a bearing to the problem. The final model was made in proportion to the proportion in order to show the interrelationship between variables. set of relations used in the model comparing with the real processes. According to Forrester, (1986) “effectiveness of a model depends on how it uses the wide range of information arising from the system being represented”. When dealing with this issue two databases have been referred to. These are mental database and written database. Numerical database was not used as it posed challenge in obtaining information. 5. Conclusion: The imitation model has been used in experiments to establish causes for the varying number of people contributing to each variable. Coming up with acceptably real behavioural models or trends is difficult but analysing empirical data gives a clear indication that the problems handled play a key role in determining the results from a process and coming up with models and simulations on that basis is important in project planning. References: Dimitrios Vlachos, Patroklos Georgiadis, Eleftherios Iakovou, 2006. A system dynamics model for dynamic capacity planning of remanufacturing in closed-loop supply chains. Industrial Management Division, Department of Mechanical Engineering, Aristotle University of Thessaloniki, P.O. Box 461, 541 24 Thessaloniki, Greece. Jay W. Forrester, 1992. System Dynamics, System Thinking, and Soft OR, Massachusetts Institute of Technology. Cambridge, MA, 02139, USA. Jay W. Forrester.1986, Lessons from System Dynamics Modelling. Massachusetts Institute of Technology. Cambridge, Massachusett, 02139, USA. John D. Sterman, 2001. System Dynamics Modelling: TOOLS FOR LEARNING IN A COMPLEX WORLD. Caledonia Management Review, Vol 43.NO.4. John D. Sterman, 1992. System Dynamics Modelling for Project Management. Massachusetts Institute of Technology. Cambridge, MA, 02139, USA. Ricardo Rodriguez-Ulloa and Alberto Paucar-Caceres, 2004. Soft System Dynamics Methodology (SSD): A Combination of Soft System Methodology (SSM) and System Dynamics (SD), Manchester Metropolitan University Business School. Aytoun Street, Manchester. 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