Reveillac - MODELING AND SIMULATION OF LOGISTICS FLOWS: theory and fundamentals

1. 3 Optimal Paths
2. 4 Dynamic Programming
3. 5 Scheduling with PERT and MPM
4. 7 Trees, Tours and Transport
5. 8 Linear Programming
6. 9 Modeling Road Traffic
7. Appendix 1: Standard Normal Distribution Table

1. Introduction
2. 2 Elements of Graph Theory
3. 3 Optimal Paths
4. 4 Dynamic Programming
5. 5 Scheduling with PERT and MPM
6. 6 Maximum Flow in a Network
7. 7 Trees, Tours and Transport
8. 8 Linear Programming
9. 9 Modeling Road Traffic
10. 10 Software Programs
11. Appendix 2: GeoGebra

Series Editor

Jean-Paul Bourrires

Jean-Michel Rveillac

First published 2017 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.

Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms and licenses issued by the CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the undermentioned address:

ISTE Ltd
27-37 St Georges Road
London SW19 4EU
UK

www.iste.co.uk

John Wiley & Sons, Inc.
111 River Street
Hoboken, NJ 07030
USA

www.wiley.com

ISTE Ltd 2017

The rights of Jean-Michel Rveillac to be identified as the author of this work have been asserted by him in accordance with the Copyright, Designs and Patents Act 1988.

Library of Congress Control Number: 2016957972

British Library Cataloguing-in-Publication Data

A CIP record for this book is available from the British Library

ISBN 978-1-78630-106-2

In a society in which the fundamental role of transport only fully appears when it does not work or works badly, logistics does not tend to be seen negatively. This is not due to the fact that the average citizen possesses knowledge of the processes behind it, the requirements and the missions of such a phenomenon, but because very often logistics seem almost foreign, merely associated with transportation and the mobility of goods. A social representation of logistics would not only require one to envisage the geographical division of work but also consider the infinite consequences that come from a mass consumption system, an absolute social phenomenon described by E. Durkheim.

The term logistics covers three crucial dimensions regarding the flow of goods, which every business that produces such commodities will encounter: supply, flow within the business one thus speaks of production management and distribution. Every movement of people or goods, whether the destination be near or far, will demand space, time and energy. Logistics, perceived as a general discipline in the realm of flow management, is somewhat strange in that its effectiveness is inversely proportional to its visibility. The better the performance, the less visible it becomes and many economic powers, both local and global, will only realize their main concerns when, for many reasons, they are unable to find answers to the complex problems that they set out to solve.

Thoughts arise from action in order to return to action, H. Wallon once affirmed. If there is one world in which this quotation proves productive, it is in that of logistics. Logistics is to transportation and mobility what thoughts are to action. As demonstrated in the few historical pages of the work that you are currently reading, though for centuries soldiers have created flows that enable their armed forces to move systematically, it was not until the second half of the last century, during which the concept of mobility was made commonplace in Western societies along with the emergence of global labor division and a globalized society of mass consumption, that the rationalized organization of flow became a crucial discipline for the productivity of firms. Assimilated in chart of accounts as an expenditure account, despite everything logistics is still very often associated with loss for businesses that produce goods. It is about time that it is seen as an asset.

Logistics has established itself using empirical knowledge that is modeled so as to offer us tools that rationalize modes of mobility, and each concept or logistical model is immediately confronted with reality in terms of effectiveness: modify the packaging of your product and the characteristics of transportation are immediately modified. Change the providers and you change the chain of supply and the storage techniques. Create a new product and it is your chain of production that must then be remodeled.

We could, for example, be faced with the task of delivering four parcels in two different locations. Easy! But we could also be faced with the task of organizing the rounds of 140 drivers (some employed by our business, others temporarily contracted and even more subcontracted), each with a vehicle that contains over 10 tons of goods spread throughout more than 250 parcels to be delivered to 50 different locations. Some of these delivery locations can belong to the same client and be several dozens or hundreds of kilometers away. Here, we are faced with a jigsaw puzzle that consists of over a million possibilities. Rational types would opt to travel in a straight line, losing time, space and money. It is better to maintain to a Pascalien vision of modelized management of uncertainties. Yet the creation of a systemic and complex vision of flow reality and its crucial concrete effectiveness demands one to abandon ones common sense.

Until the oil crisis of the 1970s, needs for the future always exceeded those of the past. Consequently, there was little concern about vehicle fill rate, the pollution caused or the global cost of stocks as long as the trip was profitable.

At the start of the 21st Century, conditions changed. In the international framework of sustainable mobility, for reasons regarding productivity, traceability, quality, etc., it is no longer possible to ignore the optimization of flux or to misunderstand logistics. The knowledge acquired by logistics coordinators must be shared, spread and popularized, such that mobility is perceived as one of the fundamental concepts in sustainable development and an inevitable dimension of profitability of productive actions. A product can only be regarded as complete insofar as it is available to anyone who needs it: logistics, which enables this access, is an integral and inescapable part of industry.

Every exchange of goods requires information to be transferred between those concerned. Today, manufacturers must find the best balance between geo-space, concerning land, and cyberspace, concerning the virtual land of exchanging data.

Logistics are everywhere, all the time. Of course, all is not logistic, but logistics can be perceived in everything. Yet today, knowledge of logistics is only shared between specialists. The aim of this book is to make sense of the issue to explain modelizations coming from knowledge accumulated by logistics coordinators in order to find realistic applications. This book, dotted with numerous graphs and images, is not only a collection of techniques that help produce decisions. The intentin is to spread this knowledge onto a public that is much greater in number than the experts. My friend J.-M. Reveillac has purposefully limited vast mathematical demonstrations in order to make the modelizations of flux management understandable while adding value to operational research.