Models and Methods for Multi-Actor Systems

2010/2011The study of the models and methods to apply to multi-actor systems is a widely discussed research topic in the related scientific literature. The multi-actor systems are defined as systems that are characterized by the presence of several autonomous elements, of different decision makers and of complex rules that allow the communication, the coordination and the connection of the components of such systems. Commonly, the study of Multi-Actor System, MAS, recalls the well-known issues concerning the multi-agent systems. The research topic related to the multi-agent system firstly started to appear in scientific literature in 1980s, mainly in relation to the computer science and artificial intelligence. In this dissertation, in particular, the study of the multi-agent systems, and specifically of the multi-actor systems, is taken into account merely in relation to the distinctive features of complexity that characterize such systems and not to the issues concerning the agent-oriented software engineering. Therefore, the research results presented in this thesis are focused on the development and on the realization of innovative models and methodologies to face the management and the decision making mechanisms applied to complex multi-actor systems. This dissertation especially focuses on two different examples of multi-actor systems in two very diverse perspectives. The former deals with the research problem related to intermodal transportation networks, while the latter with the so called consensus problem in distributed networks of agents. Concerning the research problem related to the intermodal logistic systems, the research activity addresses the management of their more and more increasing complexity by the applications of the modern Information and Communication Technologies (ICT) tools that are key solutions to achieve the efficiency and to enhance logistics competitiveness. The related scientific literature still seems lacking in addressing with adequate attention the impact of these new techniques on the management of these complex systems and, moreover, there is an apparent lack of a systematic and general methodology to describe in detail the multiplicity of elements that can influence the dynamics and the corresponding information and decision making structure of intermodal transportation systems. The innovative results presented in this dissertation are focused on the development of an Integrated System, IS, devoted to manage intermodal transportation networks at the tactical as well as operational decision level to be used by decision makers both in off-line planning and real time management. To specify the Integrated System, a reference model is developed relying on a top-down metamodeling procedure. These innovative research results are a contribution to bridge the gap and to propose not only a systematic modeling approach devoted to describe a generic multi-actor logistic system, but also a management technique based on a closed loop strategy. The second example of application is focused on a topic that is widely discussed in scientific literature related to the study of the multi-actor collective behaviors in a distributed network. The interaction protocols that allow the agents to reach the convergence to a common value is called consensus or agreement problem. This research problem is particularly studied in the context of cooperative control of multi-agent systems because the agents are autonomous, independent and have to interact in a distributed network. The presented research results address the investigation of new and fast alignment protocols that enhance the performances of the standard iteration protocols for particular topologies of digraphs on the basis of a triangular splitting of the standard iteration matrix. The examined examples, the models and the methodologies applied to analyze them, are very different in the two cases and this testifies the large extent of research problems related to the multi-actor systems.L’analisi di modelli e metodi da sviluppare e da applicare nel contesto dei sistemi multi-attoriali costituisce un tema molto variegato e discusso nella letteratura scientifica internazionale. I sistemi multi-attoriali sono sistemi che si contraddistinguono per la presenza di molti elementi autonomi diversi tra loro, di molteplici decisori e di complesse regole che determinano la comunicazione, il coordinamento e la connessione all'interno di tali sistemi. Frequentemente, facendo riferimento a sistemi multi-attoriali, Multi-Actor Systems, si richiama il tema molto attuale dei sistemi multi agente, Multi-Agent Systems. Diffusisi a partire dal 1980, i sistemi multi agente sono spesso studiati in relazione alle metodologie di sviluppo dell'ingegneria del software. Nel presente lavoro di tesi, il tema dei sistemi multi-agente, ed in particolare di quelli multi-attoriali, non viene analizzato in questo contesto, ma in relazione alle tecniche decisionali da adottare per gestire sistemi caratterizzati da un alto livello di complessità. In tale ambito, i risultati presentati all'interno di questa dissertazione sono focalizzati sullo sviluppo e sulla realizzazione di nuovi metodi e di nuove metodologie, in grado di affrontare la gestione della complessità dei sistemi multi-attoriali. Vengono in particolare esaminate due diverse problematiche, in due contesti completamente diversi e con tecniche differenti, a testimoniare le vaste applicazioni che riguardano i sistemi multi-attoriali. I problemi analizzati sono incentrati, in primo luogo, su un'applicazione inerente la gestione di sistemi logistici intermodali ed, in secondo luogo, sullo studio delle regole o protocolli di interazione in una rete distribuita di agenti autonomi. Per quanto riguarda l'aspetto legato ai sistemi intermodali di trasporto, un tema molto discusso nella letteratura scientifica recente, l'analisi si focalizza sulla gestione della loro sempre crescente complessità, tramite l'utilizzo di sistemi dell'Information and Communication Technology, ICT. Questi strumenti richiedono metodi e modelli che sono innovativi rispetto a quanto è presente nella letteratura scientifica, all'interno della quale è stata riscontrata la mancanza di un approccio sistematico e sufficientemente ad alto livello per la realizzazione di una metodologia in grado di descrivere allo stesso tempo sia la molteplicità di elementi che influenzano le dinamiche e le informazioni, sia le strutture decisionali dei sistemi intermodali. L'innovazione dei risultati presentati in questa tesi si focalizza proprio sull'esigenza di proporre un sistema integrato, Integrated System (IS), basato su un metamodello delle reti intermodali di trasporto, che fornisca un valido supporto ai decisori sia a livello tattico che operativo. Il secondo aspetto affrontato in questa tesi riguarda un altro argomento di largo ed attuale interesse nella letteratura scientifica, che viene comunemente chiamato problema del consenso. Questo problema affronta lo studio di come diversi agenti autonomi collocati su una rete distribuita siano in grado di comunicare e di accordarsi su un valore comune, senza la presenza di un decisore centrale. A questo scopo ci sono degli algoritmi che specificano le regole o protocolli di interazione tra i diversi agenti. In tale contesto, i risultati proposti si focalizzano su alcune problematiche rappresentate dal protocollo classico del consenso e soprattutto sulla sua scarsa efficienza in particolari conformazioni delle reti di agenti. Il lavoro di tesi propone, quindi, un approccio di suddivisione, splitting, della matrice standard di iterazione, di tipo triangolare, che presenta notevoli vantaggi in termini di performance rispetto all'algoritmo classico. Lo studio di problemi multi-attoriali, pertanto, richiede lo sviluppo di innovative metodologie decisionali e di nuovi metodi di gestione delle comunicazioni, per rispondere al livello sempre crescente di complessità, offrendo in questo modo alcuni spunti molto interessanti per la ricerca.XXIV Ciclo198

Analysis of Impact of ICT Solutions in International Freight Management

The paper analyses a crucial problem in the international freight management and assesses the application of an innovative solution based on Information and Communication Technology (ICT) tools. In order to improve the customs clearance procedures, the paper analyses the main anomalies and bottlenecks related to international freight management of a case study by modelling the customs clearance activities in the Unified Modelling Language framework. Moreover, some novel ICT based solutions are proposed in order to optimize suited performance indices. The flow of goods and information involved in the case study is simulated in different scenarios in order to highlight the improvements reached by using ICT solutions. The simulation results point out the huge impact of ICT on customs clearance operations

Satisfaction of Istanbul Citizens with Urban Public Transportation

Transportation is one of the most challenging urban subsystems to transform in an environmentally friendly and futuristic way. Many city dwellers use a variety of modes of transportation. An efficient and sustainable urban transportation system must include many modes of transportation for a single trip. Intermodal combinations are essential for urban transportation efficiency. Public transportation and commuting are essential elements of multimodal travel. In urban areas, a mix of bicycles, vehicles, and public transportation is prevalent, while in rural areas, car, and public transportation are more prevalent. By examining the characteristics that lead customers to prefer water transportation over Metrobus and Marmaray, we hope to gain a better understanding of how the Asian and European sides of Istanbul are traversed. The number of participants in the "Maritime Transportation Satisfaction Survey" was 2,343. During this period, a model was built using the survey item "frequency of use" (dependent variable). Numerous survey examines and evaluation methodologies were utilized to determine the effectiveness of this strategy. The study examines the intermodal travel motivations and the evaluation of transportation options by multimodal users. For a successful urban transportation system, urban planning must take into account multimodal travel behavior and user expectations. There are initiatives to improve water transportation in Istanbul. Conventional maritime transportation is inadequate from start to finish. An integrated route optimization method is needed to increase the efficiency of maritime transportation. We believe that by strengthening maritime transportation links will increase water consumption. Before the coronavirus pandemic, 2,343 maritime carriers were evaluated on March 8, 2020. (Different surveys were conducted among the passengers of City Lines, Private Motors, Metrobus, and Marmaray to compare their choices and reasons.) SPSS will be used for data analysis. Multivariate Statistical Analysis relies on Multinomial Logistic Regression and Discriminant Analysis models, both of which use the K-fold and Leave-one-out criteria to decide which attributes are valid in the regression model and which are valid in the discriminant approach. The Hosmer-Lemeshow test criteria yielded a p-value greater than 0.05 for MLR characteristics

Improving transferability between different engineering stages in the development of automated material flow modules

For improving flexibility and robustness of the engineering of automated production systems (aPS) in case of extending, reducing or modifying parts, several approaches propose an encapsulation and clustering of related functions, e.g. from the electrical, mechanical or software engineering, based on a modular architecture. Considering the development of these modules, there are different stages, e.g. module planning or functional engineering, which have to be completed. A reference model that addresses the different stages for the engineering of aPS is proposed by AutomationML. Due to these different stages and the integration of several engineering disciplines, e.g. mechanical, electrical/electronic or software engineering, information not limited to one discipline are stored redundantly increasing the effort to transfer information and the risk of inconsistency. Although, data formats for the storage and exchange of plant engineering information exist, e.g. AutomationML, fixed domain specific structures and relations of the information, e.g. for automated material flow systems (aMFS), are missing. This paper presents the integration of a meta model into the development of modules for aMFS to improve the transferability and consistency of information between the different engineering stages and the increasing level of detail from the coarse-grained plant planning to the fine-grained functional engineering.Comment: 11 pages, https://ieeexplore.ieee.org/abstract/document/7499821

Adapting to Slow-Moving Crises: The Personal Protection Equipment Supply Chain in the Time of COVID19

In this paper, we look at the supply chain for PPE during the COVID-19 pandemic of 2020. We look at the way the supply chain has responded to the pandemic, the coordination of the supply chain relative to the needs of primary users, and the consequences of its use. We find that the supply chain has continued to function more as a commercial supply chain than as an emergency supply chain largely because of a lack of centralized coordination. We include an analysis of existing concepts as they apply to this supply chain, but also incorporate preliminary results from a series of interviews with key players in this and related supply chains

AGENT-BASED DISCRETE EVENT SIMULATION MODELING AND EVOLUTIONARY REAL-TIME DECISION MAKING FOR LARGE-SCALE SYSTEMS

Computer simulations are routines programmed to imitate detailed system operations. They are utilized to evaluate system performance and/or predict future behaviors under certain settings. In complex cases where system operations cannot be formulated explicitly by analytical models, simulations become the dominant mode of analysis as they can model systems without relying on unrealistic or limiting assumptions and represent actual systems more faithfully. Two main streams exist in current simulation research and practice: discrete event simulation and agent-based simulation. This dissertation facilitates the marriage of the two. By integrating the agent-based modeling concepts into the discrete event simulation framework, we can take advantage of and eliminate the disadvantages of both methods.Although simulation can represent complex systems realistically, it is a descriptive tool without the capability of making decisions. However, it can be complemented by incorporating optimization routines. The most challenging problem is that large-scale simulation models normally take a considerable amount of computer time to execute so that the number of solution evaluations needed by most optimization algorithms is not feasible within a reasonable time frame. This research develops a highly efficient evolutionary simulation-based decision making procedure which can be applied in real-time management situations. It basically divides the entire process time horizon into a series of small time intervals and operates simulation optimization algorithms for those small intervals separately and iteratively. This method improves computational tractability by decomposing long simulation runs; it also enhances system dynamics by incorporating changing information/data as the event unfolds. With respect to simulation optimization, this procedure solves efficient analytical models which can approximate the simulation and guide the search procedure to approach near optimality quickly.The methods of agent-based discrete event simulation modeling and evolutionary simulation-based decision making developed in this dissertation are implemented to solve a set of disaster response planning problems. This research also investigates a unique approach to validating low-probability, high-impact simulation systems based on a concrete example problem. The experimental results demonstrate the feasibility and effectiveness of our model compared to other existing systems

Įvairiarūšių krovinių maršrutų žaliajame transporto koridoriuje tyrimas

Disertacijoje pateikiami įvairiarūšių krovinių (IK) maršrutų žaliajame transporto koridoriuje (ŽTK) tyrimo rezultatai. Pagrindinis darbo objektas – įvairiarūšių krovinių optimalaus maršruto žaliuojame transporto koridoriuje modelis, skirtas neigiamiems transporto poveikio aplinkai rodikliams (TPAR) mažinti (maršruto atstumui, trukmei ir emisijos kiekiui). Siekiant užtikrinti nenutrūkstamą ir savalaikę įvairiarūšių krovinių (IK) plėtotę žaliuoju transporto koridoriumi (ŽTK), norint išvengti gaišties, maršrutų keitimo ar transporto priemonių (TP) prastovų, svarbu įvertinti vidutinio transporto priemonių srauto (TPS) greičio priklausomybę nuo kelių oro sąlygų (KOS). Pagrindinis darbo tikslas – sukurti įvairiarūšių krovinių vežimo žaliuoju transporto koridoriumi matematiniu modeliavimu pagrįstą optimalaus maršruto parinkimo modelį, naudojant kelių oro sąlygų (KOSIS) stotelių ir eismo intensyvumo (EII) skaičiuotuvų duomenų bazes. Disertaciją sudaro įvadas, trys skyriai, bendros išvados, naudotos literatūros ir autoriaus publikacijų disertacijos tema sąrašas. Įvadiniame skyriuje suformuluota tiriamoji problema, darbo aktualumas, tyrimų objektas, darbo tikslas ir uždaviniai, tyrimų metodika, darbo mokslinis naujumas, rezultatų praktinė reikšmė, ginamieji teiginiai. Įvado pabaigoje pristatytos autoriaus paskelbtos publikacijos disertacijos tema, aprašoma disertacijos sandara. Pirmajame skyriuje nagrinėjami moksliniai literatūros šaltiniai ir darbai, susiję su įvairiarūšių krovinių plėtote žaliuoju transporto koridoriumi (ŽTK) ir intelektinių transporto sistemų teikiamų duomenų taikymo problematika. Tiriamos nepalankių oro sąlygų keliuose įtaka. Antrajame skyriuje pateikti ITS sudedamieji elementai, patikslintos ITS ir ŽTK sąvokos, sudarytas ŽTK topologinis žemėlapis, suformuluotas tyrimo algoritmas optimaliam maršrutui nustatyti pagal trumpiausią maršruto atstumą, trukmę ir mažiausią emisijos kiekį. Šiam sprendimui sukuriamas Visual Basic application (VBA) programavimo kalbos kodas taikant dinaminio programavimo Belmano modelį optimalaus įvairiarūšio transporto maršrutui spręsti. Modelis įvertina vidutinio TPS greičio priklausomybę nuo kelių oro sąlygų. Trečiajame skyriuje pateikti Lietuvos kelių oro sąlygų įtakos vidutiniam greičiui tyrimai ir rezultatai ŽTK maršrutuose, taikant dinaminio programavimo metodą, pagal trumpiausio atstumo, trukmės funkciją ir emisijos kiekį. Disertacijos tema paskelbta vienuolika mokslinių publikacijų: viena – ISI Web of Science duomenų bazėje, dvi – recenzuojamose mokslo žurnaluose, trys – recenzuojamuose užsienio tarptautinių konferencijų leidiniuose, penkios – recenzuojamuose Lietuvos tarptautinių konferencijų leidiniuose

Decision Support System Approach for the Management of Complex Systems in Transportation and Logistics

L'analisi e la gestione dei sistemi complessi e delle loro ripercussioni in diversi aspetti della vita quotidiana sono tematiche che continuano ad attrarre molta attenzione nella letteratura scientifica. Si considerino, ad esempio, il trasporto marittimo e su strada, i moderni sistemi di assistenza sanitaria, le catene di distribuzione integrate, i processi industriali o, ancora, il nuovo paradigma di citt\ue0 intelligente: \ue8 evidente come in tutti questi contesti vi sia sempre pi\uf9 la necessit\ue0 di analizzare e gestire elementi eterogenei, collegati tra loro al fine di raggiungere un obiettivo comune altrimenti non realizzabile. Tuttavia, il processo decisionale in tali ambiti richiede competenze trasversali che abbracciano svariate discipline, rendendo la gestione di questi sistemi molto complessa e, spesso, inefficace. I Sistemi di Supporto alle Decisioni (DSS) ben si adattano alla previsione ed al controllo dei sistemi complessi grazie a: la loro capacit\ue0 di integrare varie fonti di dati ed informazioni; l'applicazione di modelli formali tipici di diverse discipline; la possibilit\ue0 di interagire costantemente con il sistema considerato. L'obiettivo di questo lavoro di tesi \ue8 quello di definire un approccio generale basato sul concetto di DSS per la gestione di sistemi complessi nel settore dei trasporti e della logistica, e di applicare tale approccio a tre problemi di grande interesse oggigiorno: 1) il problema della ricollocazione dei veicoli nei servizi di car sharing, 2) la gestione intelligente delle operazioni di carica dei veicoli elettrici presso le infrastrutture pubbliche e 3) l'ottimizzazione delle operazioni di drayage nel trasporto container. In particolare, il focus della ricerca \ue8 rivolto al cuore del DSS, ovvero alla parte che direttamente supporta il processo decisionale: i moduli di ottimizzazione e simulazione e le loro interazioni. Vengono considerati diversi approcci di modellazione, simulazione ed ottimizzazione, evidenziando il carattere totalmente generale dell' approccio considerato. I risultati ottenuti nelle diverse applicazioni sottolineano l'efficacia dei DSS nel migliorare il processo decisionale, portando ad un miglioramento generale delle prestazioni dei sistemi in esame. In particolare: 1) l'applicazione del DSS permette di ottimizzare i set-point per l'introduzione di un sistema di incentivi economici atto a risolvere il problema di ricollocazione dei veicoli nei servizi di car sharing, garantendo un miglioramento delle prestazioni del sistema, anche in condizioni di quasi saturazione; 2) il DSS permette la formalizzazione di un approccio leader-follower per il coordinamento delle operazioni di ricarica di veicoli elettrici che tenga conto contemporaneamente sia dei requisiti dell'utente che quelli della rete elettrica; infine, 3) il DSS consente di migliorare l'efficienza delle operazioni di drayage nel trasporto containter, riducendo i costi di trasporto.In recent years, the analysis and management of complex systems and their impacts in many aspects of the every-day life are topics that attract a lot of attention in the scientific literature. Consider for instance road and maritime transportation, modern healthcare systems, integrated supply chains, industrial processes or the new paradigm of smart cities: it is apparent that in all these contexts there is an increasing need of analysing and managing heterogeneous elements, networked together in order to reach a common goal otherwise not achievable. However, making decisions concerning such systems requires specific competences from many disciplines, leading to a very complex and often ineffective management process. Decision Support Systems (DSSs) can strengthen the capacity of predicting and controlling complex systems by integrating various sources of data and information, applying formal models typical of diverse and isolated disciplines and constantly interacting with the considered system. The goal of this work is to define a general approach based on the DSS concept for the management of complex systems in transportation and logistics and to apply it to three problems of great interest nowadays: 1) the user-based vehicle relocation problem} in car sharing services, 2) the smart management of electric vehicles charging operations and 3) the container drayage problem. In particular, the focus of the research is on the core of the DSS, i.e., on the part that directly supports the decision making process: optimization modules, simulation modules and their interactions. Different modelling, simulation and optimization approaches are applied, highlighting the generality of the considered approach regardless the specific context analysed. Results show the ability of DSSs to enhance the effectiveness of the decision process, thus leading to an improvement of the considered systems performance. In particular: 1) the application of the DSS allows to optimize the set-points of an incentive policy designed to solve the vehicle relocation problem in car sharing services, guaranteeing an effective relocation and improving the system performance even in the case of nearly saturated offer; 2) the DSS allows the formalization of a leader-follower approach for the coordination of electric vehicles charging operations which takes into account simultaneously electric grid and drivers requirements; finally, 3) the DSS allows to improve the efficiency of drayage operations in container transportation, reducing total transportation costs

Design and Development of Geographical Information System (GIS) Map for Nuclear Waste Streams

A nuclear waste stream is the complete flow of waste material from origin to treatment facility to final disposal. The objective of this study was to design and develop a Geographic Information Systems (GIS) module using Google Application Programming Interface (API) for better visualization of nuclear waste streams that will identify and display various nuclear waste stream parameters. A proper display of parameters would enable managers at Department of Energy waste sites to visualize information for proper planning of waste transport. The study also developed an algorithm using quadratic Bézier curve to make the map more understandable and usable. Microsoft Visual Studio 2012 and Microsoft SQL Server 2012 were used for the implementation of the project. The study has shown that the combination of several technologies can successfully provide dynamic mapping functionality. Future work should explore various Google Maps API functionalities to further enhance the visualization of nuclear waste streams

Air Force Institute of Technology Research Report 2000

This report summarizes the research activities of the Air Force Institute of Technology’s Graduate School of Engineering and Management. It describes research interests and faculty expertise; lists student theses/dissertations; identifies research sponsors and contributions; and outlines the procedures for contacting the school. Included in the report are: faculty publications, conference presentations, consultations, and funded research projects. Research was conducted in the areas of Aeronautical and Astronautical Engineering, Electrical Engineering and Electro-Optics, Computer Engineering and Computer Science, Systems and Engineering Management, Operational Sciences, and Engineering Physics