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rms of the smaller manufacturer, and even the service industry, especially as the cost of raw materials is rising in the face of increased demand for core materials (Abdul-Nour, Lambert et al. 1998, Khan, Sarker 2002).
　　JIT is difficult to implement and requires considerable investment in the production processes (Hansen, Mouritsen 2006, Houghton, Portougal 1997). It is impossible to implement JIT unless there has been a programme of business process redesign to allow such minimum stock levels to be held, and this can present a large investment cost in the firm which may or may not ultimately benefit from such an inventory management programme. JIT requires the firm to invest heavily in partnerships with suppliers as well and to evaluate the supply chain from almost every angle to prevent a total collapse of the production system (David, Eben-Chaime 2003). This is because there is little room for error in the process, if demand is poorly predicted and is higher than expected then the firm will run out of the raw materials of production and may lose custom (Kelle, Al-khateeb et al. 2003). If lower than predicted the firm will not have the capacity to store inventory (die to process redesign). Further if suppliers fail to deliver for any reason the process will come to an abrupt halt. JIT therefore requires a significant amount of managerial information from both the external market and the internal processes to get right and there have been many cases of difficult implementation, especially in smaller companies (Abdul-Nour, Lambert et al. 1998).
　Notwithstanding this there is a lot of evidence that with more and sophisticated modelling techniques from increasingly advanced technology, JIT systems are getting easier to implement (White, Prybutok 2001, Yasin, Small et al. 1997). Therefore as long as the systems are set up correctly there are major advantages in reducing the waste of inventory throughout the process of manufacturing. Because of its requirements, and making everything subordinate to the level of inventory, it is not applicable for JIT systems to be used in conjunction with the Theory of Constraints, as managers are unable to subordinate all decisions within the production process to a ‘bottleneck’. Therefore some would argue that JIT systems are less flexible, or certainly allow less flexibility that TOC does (Yasin, Small et al. 1997).
　　Programme Evaluation and Review Technique (PERT)
　　Put simply a PERT map is a model of complex processes which occur to facilitate an outcome (Castro, Gómez et al. 2008). The PERT framework is very similar and often used in conjunction with a critical pathway diagram which shows the key processes involved in such an outcome (Mummolo 1997). PERT modelling makes a number of assumptions and has many conventions. In drafting a PERT chart the processes will be numbered in tens, to allow for further additions as the model grows. Further the model assumes that there is a linear relationship between the processes and therefore a number of key relationships (critical pathways) are determined (Cox 1995). These are often termed predecessor events and successor events. The PERT model deals with time in a number of ways giving an optimistic time and a pessimistic time for the completion of a process. It allows managers to view a project, task or process in a way which will help to maximise the efficiency of such a task in terms of a number of variables (Ship本论文由英语论文网提供整理，提供论文代写，英语论文代写，代写论文，代写英语论文，代写留学生论文，代写英文论文，留学生论文代写相关核心关键词搜索。