1,721,034 research outputs found
A Management of Intensive Care Unit based on the System Dynamics Model
No full textNowadays the increase of the world population’s age and the progressive specialization of care techniques and processes are the main driver of demand’s increase for health services. Coping with the mismatches between the increasing demand and the limited capacity of resources, the hospital facilities are showing a more consolidated approach to re-design the existing processes through the application of Lean Manufacturing methodologies. On the other hand, the innovation’s development and implementation often degenerates in time wasting and additional costs. This article illustrates the utility of modeling and simulation processes (M&S) in a System Dynamics environment and it shows a versatile-generally-applicable model aimed at patient flow monitoring in an Intensive Care Unit (ICU). The proposed model reveals at the same time a valuable decision support tool that identifies “systemic” problems and describes the effects of the “Lean” policies in such a way as to prevent the risks and costs related to innovation processes
NEW FORMALISM FOR PRODUCTION SYSTEMS MODELING
No full textThis paper aims to highlight the usefulness of the simulation, analyzing in particular, two simulative techniques: the Discrete Event Simulation and the System Dynamics. The main objective is to propose a simulation methodology to use to model, analyze and control any type of system. This approach is supported by three studies, belonging to different sectors, which demonstrate the utility of adopting a simple and common scheme of analysis
A decision support tool, implemented in a system dynamics model, to improve the effectiveness in the hospital emergency department
No full textThe emergency department of a hospital is, among all areas in which lean policies are focused, the one that has received the most attention. The emergency room, in fact, plays a vital role in providing primary care to patients and is also recognized for the contribution it gives to society. The important results in terms of cost savings and improving the flow due to the reduction of the waiting time of the patients, obtained from major international hospitals, were crucial to assess whether it was possible and useful to implement similar improvements in Italy, certainly not without to many problems in the provision of health services. This paper explores what can be improved for the department to be more efficient, using simulation techniques based on dynamic and continuous logics (system dynamics)
A Decision Support System based on a New Hybrid Model of Simulation
No full textIn this paper we propose a new approach, based on simulation, that support decision making in several environment: manufacturing; transportation systems; logistics. We implemented a new formalism based on Petri Nets designed in the System Dynamics logic
Airport system analysis: a probabilistic risk assessment model
No full textRisk reduction is one of the key objectives pursued by transport safety policies. Particularly, the formulation and implementation of transport safety policies needs the systematic assessment of the risks, the specification of residual risk targets and the monitoring of progresses towards those ones. Risk and safety have always been considered critical in civil aviation. An increase in airport capacity usually involves changes to runways layout, route structures and traffic distribution, which in turn effect the risk level around the airport. For these reasons third party risk becomes an important issue in airports development. Currently, were moving to a wide adoption of Safety Management Systems (SMS) which carries with it a need to undertake risk assessments, either qualitative or quantitative. The purpose of this paper is to describe and analyse safety aspects in civil airports. To avoid subjective interpretations and to increase model accuracy, risk information are collected and evaluated in a rational and mathematical manner. The method may be used to draw risk contour maps so to provide a guide to local and national authorities, to population who live around the airport, and to airports operators
Optimal size of kanban board in a single stage multi product system
No full textThe aim of this paper is to define a methodology for determining the optimal size of the supermarket (between two workstations) through the optimization of the number of kanban in a kanban board. It also identifies some production parameters that greatly influence the optimal size of a kanban board. The approach chosen is the building of a simulation model of a single stage multi-product system with Arena, while OptQuest has been used for the next optimization phase
An integrated approach to locate and allocate production and distribution sites by using simulation models
No full textIn spite of an increasing development of applied mathematics to the theory of location, just a few applications have been done about support to decision regarding the location of production and/or selling sites. This paper aims at localization of a firm, that will produce controlled leavening baking products, and its kiosks (selling points), displaced on a municipality area. To make the choice, it’s been considered the double function of the kiosk: it is a restocking point and it will be necessary to study the optimal path from the production point, that is considered known, to the kiosk itself; it is also a selling point, so it has to be located where it’s mostly perceived by the customers. The two choice dimensions, regarding an unique location, need the creation of a model able to represent the scenarios dynamism of reality. As the location of production points has been supposed known, it’s been studied the problem of kiosks location, by the optimization of attracting capacity and by minimizing the restocking cost from the production point. So, it’ been simulated a quantitative model to represent the choice behaviour of different categories customers to move in the urban area. The simulation model output gives the traffic flows on the network, where the production system (manufacturing and selling points) has been located. These results give also the inputs for a second model used to define the optimal paths on the same network. In this way, the choice model for the best path from production to selling point is able to consider the network loads. The interaction between the two models will also be useful to define the localization of the whole production system, estimating the dimension of each production and selling point
Transformation of a production/assembly washing machine lines into a Lean Manufacturing System
No full textThe scope of this work is the complete re-organization of production flow according to the Lean Thinking philosophy for the industrial applications. The complete re-organization implementation of material flow management has been performed through the supermarket sizing which replenishment kanban logic has been adopted. To implement this strategy the goal is to achieve "Interdependent connected Processes" adopting the Pull System methodology in the Just in Time production environment. From the narrow sense the JIT manufacturing philosophy is to produce the right quantity at the right time with the right quantity level. In JIT the production is triggered by a kanban signal, which comes from the costumer order or the master production schedule, the signal then flowing backwards. By implementing JIT concepts in manufacturing, many of the practitioners experience advantages such as shorter lead times, fewer inventories, and higher quality. In the case study, developed in the Whirlpool Europe Naples factory, we have a first stage that consists of sizing the amount of "Kanban reintegration" codes, and the second stage in which we have simulated with ARENA and verified the progress of production flow in the hypothesized system, that has underlined the improvement of the business performances and great flexibility
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