Letizia Nicoletti

AN APPLICATION OF MODELING AND SIMULATION TO SUPPORT INDUSTRIAL PLANTS DESIGN

The focus of the research work presented in this article is the design of an industrial plant devoted to produce different types of hazelnuts-based products. The industrial plant design is initially based on a traditional approach (production process flow charts analysis and plant layout study) and it is then supported by a simulation model mainly used to investigate the system behavior in different operative scenarios. The industrial plant simulation model (called HAZIMUT, HAZelnuts Industrial plant design and management based on advanced simulation Models Utilization) recreates the entire hazelnuts production process (based on nine different production lines). The HAZIMUT simulation model is used to evaluate the effects — caused by multiple changes in the production lines capacities — on multiple performance measures based on machines levels utilization, work in process and production system productivity. The simulation results show how variations in production lines capacities generate an over-reaction...

Smart operators in industry 4.0: A human-centered approach to enhance operators’ capabilities and competencies within the new smart factory context

Abstract As the Industry 4.0 takes shape, human operators experience an increased complexity of their daily tasks: they are required to be highly flexible and to demonstrate adaptive capabilities in a very dynamic working environment. It calls for tools and approaches that could be easily embedded into everyday practices and able to combine complex methodologies with high usability requirements. In this perspective, the proposed research work is focused on the design and development of a practical solution, called Sophos-MS, able to integrate augmented reality contents and intelligent tutoring systems with cutting-edge fruition technologies for operators’ support in complex man-machine interactions. After establishing a reference methodological framework for the smart operator concept within the Industry 4.0 paradigm, the proposed solution is presented, along with its functional and non-function requirements. Such requirements are fulfilled through a structured design strategy whose main outcomes include a multi-layered modular solution, Sophos-MS, that relies on Augmented Reality contents and on an intelligent personal digital assistant with vocal interaction capabilities. The proposed approach has been deployed and its training potentials have been investigated with field experiments. The experimental campaign results have been firstly checked to ensure their statistical relevance and then analytically assessed in order to show that the proposed solution has a real impact on operators’ learning curves and can make the difference between who uses it and who does not.

SIMULATION, ANALYSIS AND OPTIMIZATION OF CONTAINER TERMINALS PROCESSES

The freight logistics includes all the processes needed to supply industry, retailers and wholesalers and final customers with goods. Such processes generate a flow of goods that, in the global supply chain, mainly relies on the activities carried out within worldwide container terminals. In this paper, the authors present a simulation model of a real container terminal. After some preliminary analyses, the simulation model is first used with Design of Experiments and Analysis of Variance to investigate the effects of different resources allocations (i.e., number of forklifts and tractors) and some parameters (i.e., inter-arrival times, container unloading time) on the container terminal performances in terms of total number of handled containers per day. Then, based on the results achieved through the Design of Experiments and Analysis of Variance, the simulation model is used with genetic algorithms to carry out a range allocation optimization on berth assignment to incoming ships and number of tractors serving each quay crane. The aim of the optimization is the minimization of the average time spent by each ship in the port area (decreasing, as consequence, costs and increasing service level provided to final customers).

HLA-based real time distributed simulation of a marine port for training purposes

The research proposes critical issues related to cooperative training in a synthetic environment based on a federation of simulators operating in the same virtual world. The authors propose a real-time distributed simulation called ST-VP (simulation team virtual port simulator), for training purposes that is able to take safety and operative efficiency also into account. The simulators, installed on low-cost training workstations, cooperate and share the same virtual environment based on the high level architecture standard for distributed simulation (HLA). With this approach, it is possible to apply distributed simulation to a relevant number of entities and proceed with low-cost training sessions in cooperative operations in intermodal terminals.

Safety and Security in Fresh Good Supply Chain

Abstract This paper proposes a model aimed at investigating safety and security issues in fresh good supply chain. Particular attention is paid on fresh goods contamination since the increasing complexity of supply chains makes these events more likely to happen. To this end, a discrete event simulator (DES) underpinned by an analytical model has been developed as a support tool for prevention and mitigation. Indeed, the simulation model is able to recreate the disruption wave propagation along the supply chain due to a contamination event as well as the effects on the dynamic evolution of contaminated products demand taking into account complex phenomena like media campaigns. In addition, even the economic impacts in terms of costs (i.e. transportation costs, inventory costs, and lost sales) can be assessed. The potentials of the proposed simulation framework have been investigated in a real case study of a fresh food supply chain located in the north of Italy.

Hybrid approach for container terminals performances evaluation and analysis

Turnaround time, defined as the total time spent by a vessel within the port area, is one of the most important key performance measures for a container terminal. In this paper, the authors propose a hybrid approach based on simulation and genetic algorithms to investigate vessels’ turnaround time in a real container terminal under different scenarios characterised by increases in containers traffic and vessels traffic. The authors show how a modular simulation model integrated with optimisation algorithms can be used as an advanced support tool to identify resources capacity constraints and to identify how such constraints affect the vessels’ turnaround time.

Operative and procedural cooperative training in marine ports

Abstract This article faces the problem of operative and procedural cooperative training in marine ports with particular attention to harbour pilots and port traffic controller. The design and development of an advanced system, equipped with dedicated hardware in the loop, for cooperative training of operators involved in the last mile of navigation is presented. Indeed, the article describes the software and hardware development of a distributed and interoperable system composed by two simulators (the bridge ship simulator and control tower simulator). Multiple problems are faced and solved including (i) the motion of the ship at sea that is based on a 6 Degree Of Freedom (DOF) model for surge, sway and yaw and closed form expressions for pitch, roll and heave and its validation; (ii) the development of the 3D geometric models and related virtual environments of a real marine port and vessel (to provide the trainees with the sensation to experience a real port and ship environment); (iii) the design of a bridge ship replica, the bridge hardware integration and the design of the visualization system; (iv) the design and development of the control tower simulator; (v) the integration of the bridge ship simulator and control tower simulator through the IEEE 1516 High Level Architecture standard for distributed simulation.

A modelling and simulation approach to assessment of a negative binomial approximation in a multi-echelon inventory system

Some studies in the multi-echelon inventory systems literature have used a negative binomial distribution to approximate a critical random variable arising in the model. Graves (1996) developed a multi-echelon inventory model with fixed replenishment intervals, where each site follows a base stock policy. He proposed in the one-warehouse, N-retailer case a negative binomial distribution to approximate a random variable he referred to as ‘uncovered demand’. Computational evidence was provided to demonstrate the effectiveness of the approximation. Graves then suggested search procedures for approximately optimal base stock levels at the warehouse and N identical retailers under two customer service criteria: 1) probability of no stockout; 2) fill rate. A separate analytical evaluation of the negative binomial approximation has been preliminarily reported elsewhere. In the current study, we apply a modelling and simulation approach to assess whether the approximation-based search procedures, in fact, lead to optimal or near-optimal stock levels.

Modeling Energy Portfolio Scoring: A Simulation Framework

U.S. regions are expected to follow the national trend towards investment in renewable energy as part of their electricity portfolio. The progress of energy portfolios that typically involves traditional methods, such as centralized nuclear and coal-fired generation, and towards cleanerand renewable-source generation will impact economic growth and public health. Renewable electricity production must strike a balance among cost, reliability, and compatibility. The economic and health benefits obtained from developing an efficient energy portfolio make renewable energy alternatives an important consideration for regions endowed with natural resources. A portfolio mix of production method that considers the economic benefits while limiting adverse health and environmental impacts is attractive. This research proposes a System Dynamics simulation framework to support policy-making efforts in assessing the impact of energy portfolios. The authors demonstrate the utility of the framework by means of analyzing data that pertain to the U.S. Hampton Roads Peninsula Region. Modeling Energy Portfolio Scoring: A Simulation Framework

Simulation as enabling technologies for agile thinking: training and education aids for decision makers

This paper describes ongoing researches and preliminary results obtained about the potential of serious games for identification, development and education of specific soft skills. These characteristics correspond to the capability to catch at glance a solid understanding of the details in a scenario or the identification of missing elements in a set of information. This paper proposes an interdisciplinary research where expertise in modelling and simulation and serious gaming are mixed with skills in education and decision-making development. The authors’ goal is to develop a methodology and a set of games that could support decision makers to develop intuition and the capability to think and understand out of personal frameworks (Baisini et al., 2010, 2011). Preliminary experimentations are proposed by using an existing serious game ‘Sibilla’. The results are also useful to direct the research where to focus the efforts for developing ad hoc games for this very specific purpose.