Editorial from the Editor-in-Chief regarding this case of plagiarism

Philippe Mahey

1 Introduction

Plagiarismis a plague that any scientific publication in any discipline should fight anderadicate all over the world. Unfortunately, if, on the one hand, the powerfulsearch engines available on the web have helped referees to identify most ofthe cases, the increasing number of publications have on the other handfacilitated that dubious practice and the number of cases have increased. The case we are facing today in our journal is a severe one as the "authors" aremulti-recidivists who have been identified in former plagiarized papers since 2007. M. Sreenivas and T.Srinivas have this time succeeded in obtaining the publication of a plagiarizedpaper in the last issue of the RAIRO journal, but their fraud has beenidentified very quickly by different colleagues.We will briefly recall below the history of former cases involving these two persons andexpose the proofs of plagiarism about the current paper which justify itsretraction from the records of the journal.

2 A history of frauds

At leastfour papers co-authored by Sreenivas and Srinivas have been revealed in thelast two years and a report about this investigation has been published on theweb page of SIAM (http://www.siam.org/journals/plagiary/index.php).The method was nearly always the same as these papers contained entireparagraphs and abstracts copied almost verbatim from preprints or old papers inthe field (the Transportation area). We will only resume one of these factswhich is particularly instructive: as mentioned in the SIAM report, the paper: M. Sreenivasand T. Srinivas, Thetransportation: more-for-less criterion, International Journal ofStatistics and Management System, v. 3, n. 1–2, pp. 152–165,2008 is indeedplagiarized from S. Storøy: The transportation paradox revisited, postedto Optimization Online September 2007. Surprisingly, the same authors havesubmitted the same paper in parallel to the 4OR journal in october2007, but it was discovered to be plagiarized and was not published. Theeditors of that journal published an editorial in the first number of the 2009 volume(D. Bouyssou, S. Martello, F. Plastria, Plagiarismagain: Sreenivas and Srinivas, and an update on Marcu, 4OR vol. 7, n°1, 2009,pp. 17–20) with a transcription of the exchange mail between them and the authorswhere the latter did express some weak regrets without any furtherjustification. As said in the editorial, "this did not prevent them fromsubmitting their plagiarized text to another well-known OR journal, namely the European Journal of OperationsResearch "Unfortunatelyenough, the 4OR editorial was published too late to prevent the publication ofthe present paper in RAIRO.

3 The plagiarized paper

The appliedprocedure for this kind of plagiarism is always the same: select and copyparagraphs and sentences from textbooks or research reports, and finally mergethem in a personal form that is able to mislead the reader. The followingreferences prove that the paper "A short note on marginal analysis of atransportation problem", published in vol. 43, n°4, pp. 331–337, has beenalmost entirely plagiarized:

1. The entire abstract after the first sentence is a verbatim copy of a paragraph from "Deterministic modeling: linear optimization with applications", a set of course notes by Hossein Arsham.  The paragraph in question can be found at:http://home.ubalt.edu/ntsbarsh/opre640a/partVIII.htm#rmarginalFactorPri

2. The first paragraph of the introduction is taken from course notes posted by Tim Yeager at http://sorrel.humboldt.edu/%7Eeconomic/econ104/marginal/

3. The second paragraph is taken verbatim from http://www.papercamp.com/essays/Decision-Making/3884.html

4. Section 2 is a verbatim copy from K. Murty well-known textbook: http://ioe.engin.umich.edu/people/fac/books/murty/opti_model/junior-6.pdf

5. The first illustration of section 3 is taken too from Murty’s book.

6. The first paragraph of the conclusion comes from the same source as the introduction.

7. None of the references are actually referred to in the paper.

We haveasked the authors of the plagiarism to explain the situation and defendthemselves. Their answer was that they found normal to refer to other researchpapers to present the concepts. They add that "A small misunderstanding is thatthe sources of the taken matter are not mentioned in the article. It neverrepeat again". We understand in theirpoor defence that they plead guilty and promise to stop plagiarizing, but thelong history of frauds we have reported above shows that we cannot trust themand must ban them from publishing in RAIRO.

4 Conclusion

We hopethat the plagiarism activities of Sreenivas and Srinivas will now definitivelystop. The above plagiarized paper will be retracted from the electronic recordsof the RAIRO Journal. They are now banned from publishing in an internationalOR journal for the second time and their former attempts are now wellreferenced and diffused so that the whole community, from Transportation,Operations Research and Applied Mathematics areas, will have the right tools tofoil their future submissions if any.

Acknowledgements : We thank heartily the former editors of 4OR, Denis Bouyssou, Silvano Martello and Frank Plastria for identifying the plagiarism, and Douglas Arnold, President of SIAM, for his help and advice in dealing with the present plagiarism.

This paper investigates the problem of maximizing the revenue of a telecommunications operator by simultaneously pricing point-to-point services and allocating bandwidth in its network, while facing competition. Customers are distributed into market segments, i.e., groups of customers with a similar preference for the services. This preference is expressed using utility functions, and customers choose between the offers of the operator and of the competition according to their utility. We model the problem as a leader-follower game between the operator and the customers. This kind of problem has classically been modeled as a bilevel program. A market segmentation is usually defined by a discrete distribution function of the total demand for a service; in this case, the problem can be modeled as a combinatorial optimization problem. In this paper, however, we motivate the use of a continuous distribution function and investigate the nonlinear continuous optimization problem obtained in this case. We analyze the mathematical properties of the problem, and in particular we give a necessary and sufficient condition for its convexity. We introduce methods to solve the problem and we provide encouraging numerical results on realistic telecommunications instances of the problem, showing that it can be solved efficiently.

In this paper, we face a generalization ofthe problem of finding the distribution of how longit takes to reach a “target” set T of states inMarkov chain. The graph problems of finding the number of paths thatgo from a state to a target set and of finding the n-length path connectionsare shown to belong to this generalization.This paper explores how the statespace of the Markov chain can be reduced by collapsing togetherthose states that behave in the same way for the purposes ofcalculating the distribution ofthe hitting time of T.We prove the existence and the uniqueness of aoptimal projection for this aim which extends the results given in[G. Aletti and E. Merzbach, J. Eur. Math. Soc. (JEMS)8 (2006) 49–75], together with the existence of a polynomial algorithm which reaches this optimum.Some applied examples are presented. Markov complexity is defined an tested onsome classical problems to demonstrate the deeper understanding that ismade possible by this approach.

The multiparametric 0-1-Integer Programming (0-1-IP)problem relative to the objective function is a family of 0-1-IP problemswhich are relatedby havingidentical constraint matrix and right-hand-sidevector. In this paper we present an algorithm to perform a completemultiparametric analysis relative to a generalized min max objectivefunction such that the min sum and min max are particular cases.

On étudie à l'aide du système AutoGraphiX 2 (AGX 2) des relations de la forme \[ \underline{b}_{n} \, \le \, g\,\oplus \,i\, \le \, \overline{b}_{n}\] où g désigne la maille d'un graphe G=(V, E), i un autre invariant parmi la distance moyenne $\overline{l}$ , l'index λ1, l'indice de Randić R et le nombre de domination β, $\oplus$ désigne l'une des opérations+, -, ×, /, $\underline{b}_{n}$ et $\overline{b}_{n}$ des fonctions de l'ordre n du graphe qui bornent l'expression $g\oplus i$ et sont atteintes pour tout n (sauf éventuellement de très petites valeurs du fait des effets de bord). Les résultats prouvés ou discutés ci-dessous ont déjà été présentés, sousforme de conjectures, dans un article précédent paru dans RAIRO Recherche Opérationnelle [RAIRO Oper. Res. 39 (2005) 275–293].

Le Problème du Vendeur m-Péripatétique (m-PVP) est défini sur un graphe non orienté G=(V,E) où V = {1,...,n} est l'ensemble des sommets, E = {(i,j) : i,j ∈ V,i < j} est l'ensemble des arêtes et (cij) est une matrice de coûts définie sur E.Le m-PVP consiste à déterminer m cycles hamiltoniens sur G n'ayant aucune arête en commun et dont le coût total est minimal.Cet article décrit sept nouvelles heuristiques pour le m-PVP et les compare à celle qui a été proposée par Krarup en 1975.

Starting from the famous Königsberg bridge problem which Euler described in 1736, we intend to show that some results obtained 180 years later by König are very close to Euler's discoveries.

The aim of this paper is to show a polynomial algorithm for the problem minimum directed sumcut for a class of series parallel digraphs. The method uses the recursive structure of parallel compositions in order to define a dominating set of orders. Then, the optimal order is easily reached by minimizing the directed sumcut. It is also shown that this approach cannot be applied in two more general classes of series parallel digraphs.

In the paper we generalize sufficient and necessary optimality conditions obtained by Ginchev, Guerraggio, Rocca, and by authors with the help of the notion of ℓ-stability for vector functions.

This paper aims at proposing tractable algorithms to find effectively good solutions to large size chance-constrained combinatorial problems. A new robust model is introduced to deal with uncertainty in mixed-integer linear problems. It is shown to be strongly related to chance-constrained programming when considering pure 0–1 problems. Furthermore, its tractability is highlighted. Then, an optimization algorithm is designed to provide possibly good solutions to chance-constrained combinatorial problems. This approach is numerically tested on knapsack and multi-dimensional knapsack problems. The results obtained outperform many methods based on earlier literature.

Given a tree T with n vertices, we show, by using a dynamicprogramming approach, that the problem of finding a 3-coloring ofT respecting local (i.e., associated with p prespecified subsetsof vertices) color bounds can be solved in O(n6p-1 logn)time. We also show that our algorithm can be adapted to the case ofk-colorings for fixed k.

This paper studies the machine repairproblem consisting of M operating machines with S sparemachines, and R servers (repairmen) who leave for a vacation ofrandom length when there are no failed machines queuing up forrepair in the repair facility. At the end of the vacation theservers return to the repair facility and operate one of threevacation policies: single vacation, multiple vacation, and hybridsingle/multiple vacation. The Markov process and thematrix-geometric approach are used to develop the steady-stateprobabilities of the number of failed machines in the system aswell as the performance measures. A cost model is developed toobtain the optimal values of the number of spares and the numberof servers while maintaining a minimum specified level of systemavailability. Some numerical experiments are performed and someconclusions are drawn.

Recently, Y.Q. Bai, M. El Ghami and C. Roos [3] introduced a new class ofso-called eligible kernel functions which are defined by somesimple conditions.The authors designed primal-dual interior-point methods for linear optimization (LO)based on eligible kernel functionsand simplified the analysis of these methods considerably.In this paper we consider the semidefinite optimization (SDO) problemand we generalize the aforementioned results for LO to SDO.The iteration bounds obtained are analogous to the results in [3] for LO.

Soit F une famille de critères conçue pour asseoir un modèle de préférences global sur un ensemble A d'actions potentielles (ou alternatives). On se place ici dans une perspective d'aide à la décision et dans l'hypothèse où des dépendances (encore appelées interactions) sont susceptibles d'exister entre certains des critères de F. On commence (cf. Sect. 2.1) par préciser ce que signifie l'affirmation "il existe des dépendances entre certains des critères de F" (Déf. 1). On s'intéresse ensuite à deux formes classiques de dépendances (cf. Sect. 2.2). Dans la Section 3, on cherche à apporter des éléments de réponse à la question : comment mettre en évidence les dépendances s'il en existe et comment les rendre intelligibles pour les parties prenantes au processus de décision ? On définit trois types de situations particulièrement dignes d'intérêt car aisément intelligibles et faciles à cerner. Dans la section suivante, on examine les possibilités qu'offrent un certain nombre de modèles d'agrégation pour prendre en compte explicitement des dépendances. On met notamment en évidence (cf. Sect. 4.2) les possibilités et limites de l'intégrale de Choquet. Tout au long de l'article, des exemples sont introduits pour illustrer les propos.


In this paper, we describe the methodology used to tackle FranceTelecom workforce scheduling problem (the subject of the RoadefChallenge 2007) and we report the results obtained on the different data sets provided for the competition. Since the problem at hand appears to be NP-hard and due to the highdimensions of the instance sets, we use a two-step heuristical approach. Wefirst devise a problem-tailored heuristic that provides good feasiblesolutions and then we use a meta-heuristic scheme to improve the currentresults. The tailored heuristic makes use of sophisticated integer programming modelsand the corresponding sub-problems are solved using CPLEXwhile the meta-heuristic framework is a randomized local search algorithm. The approach herein described allowed us to rank 5th in this challenge.

A reformulation of a mathematical program is a formulation whichshares some properties with, but is in some sense better than, theoriginal program. Reformulations are important with respect to thechoice and efficiency of the solution algorithms; furthermore, it isdesirable that reformulations can be carried outautomatically. Reformulation techniques are widespread in mathematicalprogramming but interestingly they have never been studied under aunified framework. This paper attempts to move some steps in thisdirection. We define a framework for storing and manipulatingmathematical programming formulations and give several fundamentaldefinitions categorizing useful reformulations in essentially fourtypes (opt-reformulations, narrowings, relaxations andapproximations). We establish some theoretical results and givereformulation examples for each type.

Ce travail porte sur l'optimisation des lignesd'usinage pour la grande série. Une telle ligne comporte plusieurspostes de travail, chacun étant équipé avec boîtiers multibroches. Unboîtier multibroche exécute plusieurs opérations en parallèle.Lors de la conception en avant-projet, il est nécessaire d'affecter toutes les opérations à des boîtiers etdes postes de travail de sorte à minimiser le nombre de postes et deboîtiers utilisés. Pour ce nouveau problème d'équilibrage des lignesde production, nous proposons une approche de résolution pardécomposition en utilisant des méthodes exactes et heuristiques. Lesrésultats des tests numériques effectués sur des instances prochesdes problèmes réels sont présentés et analysés.

In this work, we study an optimal control problem dealing with differential inclusion.Without requiring Lipschitz condition of the set valued map, it isvery hard to look for a solution of the control problem. Our aim isto find estimations of the minimal value, (α), of the costfunction of the control problem. For this, we construct anintermediary dual problem leading to a weak duality result, andthen, thanks to additional assumptions of monotonicity of proximalsubdifferential, we give a more precise estimation of (α). Onthe other hand, when the set valued map fulfills the Lipshitzcondition, we prove that the lower semicontinuous (l.s.c.) proximalsupersolutions of the Hamilton-Jacobi-Bellman (HJB) equationcombined with the estimation of (α), lead to a sufficientcondition of optimality for a suspected trajectory. Furthermore, weestablish a strong duality between this optimal control problem anda dual problem involving upper hull of l.s.c. proximalsupersolutions of the HJB equation (respectively with contingentsupersolutions). Finally this strong duality gives rise to necessaryand sufficient conditions of optimality.