Industrie néolithique de longues lames en obsidienne, l’exemple d’Aknashen-Khatunarkh (Arménie, début du VIe millénaire) : sur la piste des premiers débitages par pression

Aknashen (formerly called Khatunarkh) is a small Neolithic village of the Ararat valley located 25 kilometres away from Yerevan (capital of Armenia) and 5 km South-West of Echmiadzin (Vagharshapat). Aknashen is also located at only six kilometres of another Neolithic village which is contemporary: Aratashen, a site for which we recently published a technological study of the obsidian industry. Excavations have been taking place each year since 2004 at Aknashen. Concerning the lithic material, we identified two main chaînes opératoires on obsidian (which is an abundant raw material in this region): one concerns expedient tools made on flakes and the other one relates to long regular blades. This article will concentrate on this long blade industry obtained by three techniques: standing up pressure with a crutch, pressure with a lever and indirect percussion. Otherwise, the link between the application of these techniques and the complete chaîne opératoire of these blades is difficult to figure since elements are missing and we do not know for sure if, for example, the blades knapped by standing up pressure with a crutch were obtained after the progressive reduction of the cores knapped first using indirect percussion and then pressure with a lever. But even if we still don’t understand various elements, such as the exact place (workshop) where knapping activities took place at the site, even if various “debitage” products have been found, at least this constitutes a proof that part of this chaîne opératoire was performed at the site. Furthermore, a systematic study of this material makes it possible to recognize the techniques used, but also to observe the great level of know-how of the specialists who carried out this work. Generally, standing up pressure with a crutch and indirect percussion, are two techniques used in order to obtain long regular blades, and these are better known (documented) than pressure with a lever, even if the latter has been identified in several cultures from the Neolithic, Chalcolithic and sometimes even during Early Bronze Age periods, nonetheless it has been the object of fewer studies of this kind. However, the identification of this high level of skill is important for many reasons, of course first from a pure technological point of view, but the presence of the technique of pressure with a lever on a given site can also constitute an excellent cultural marker in order to characterize cultures that are involved with it and also to help documenting more adequately exchanges (trade networks) that have been made and possible movements or contacts between populations (transmission of knowledge). In this article, a description of diagnostic specimens linked to each technique will be done and this material will be looked from a broader point of view (history of techniques and know-how) in order to have better knowledge of this culture and its possible origins (origin of this Neolithic still not precisely defined). As this research is still relatively new, many aspects are still to be confirmed and this work will carry on in the years to come.Aknashen (autrefois appelé Khatunakh) est un petit village néolithique de la vallée de l’Ararat localisé à 25 km de Erevan (capitale de l’Arménie) et à 5 km au sud-ouest d’Echmiadzin (Vagharshapat). Aknashen est également situé à seulement six kilomètres d’un autre village néolithique qui lui est contemporain : Aratashen, site pour lequel nous avons récemment publié une étude tehnologique du matériel lithique en obsidienne. Des fouilles ont eu lieu chaque année à Aknashen depuis 2004. En ce qui concerne le matériel lithique, ces travaux ont permis de mettre au jour deux chaînes opératoires principales de matériel en obsidienne (matière très abondante dans cette région) : l’une est peu élaborée sur éclats (expedient tools) et l’autre concerne la confection de longues lames régulières selon plusieurs techniques de débitage. Le présent article portera sur l’industrie laminaire de longues lames régulières obtenues par différentes techniques : pression debout à la béquille, pression au levier et percussion indirecte. La ou les chaînes opératoires qui concernent ces artefacts ne peuvent être reconstituées en entier puisque des éléments manquent et nous ne pouvons pas savoir de façon absolue si par exemple les fines lames débitées par pression à la béquille ont été obtenues après le débitage et la réduction progressive de nucléus d’abord taillés par percussion indirecte, puis par pression au levier. Mais même si divers facteurs nous échappent, dont aussi notamment les lieux exacts où s’est déroulé le débitage, même si la présence d’une panoplie de produits de débitage laisse présumer que le tout se soit déployé en tout ou en partie sur le site, une étude attentive de ce matériel a permis de diagnostiquer les techniques utilisées, mais aussi d’observer le grand niveau de savoir-faire des spécialistes qui ont effectués ce travail de pointe. De façon générale, la pression à la béquille, ainsi que la percussion indirecte, sont les deux techniques d’obtention de longues lames les mieux connues, alors que la pression au levier, même si identifiées dans plusieurs cultures du Néolithique à l’Âge du bronze a fait l’objet de peu d’études de ce genre jusqu’ici. Non seulement ce savoir-faire de haut niveau gagne-t-il à être connu d’un point de vue technologique, mais la reconnaissance du débitage par pression au levier, peut justement constituer un marqueur culturel précieux pour en arriver à caractériser des cultures, des échanges et éventuellement des mouvements ou contacts entre populations. Dans le cadre de cet article, les principaux spécimens liés à l’identification de chaque technique seront présentés, décrits et commentés et ce matériel sera replacé dans une perspective plus large pour la compréhension de cette culture et de ses origines, autant d’un point de vue de l’histoire des techniques et des savoir-faire que pour la connaissance des origines de ce Néolithique encore mal connu. Comme ces recherches sont encore relativement jeunes, bien des aspects sont encore à confirmer et ceci fait partie de travaux qui se poursuivront dans les années à venir

Order picking problems under weight, fragility, and category constraints

Warehouse order picking activities are among the ones that impact the most the bottom lines of warehouses. They are known to often account for more than half of the total warehousing costs. New practices and innovations generate new challenges for managers and open new research avenues. Many practical constraints arising in real-life have often been neglected in the scientific literature. We introduce, model, and solve a rich order picking problem under weight, fragility, and category constraints, motivated by our observation of a real-life application arising in the grocery retail industry. This difficult warehousing problem combines complex picking and routing decisions under the objective of minimizing the distance traveled. We first provide a full description of the warehouse design which enables us to algebraically compute the distances between all pairs of products. We then propose two distinct mathematical models to formulate the problem. We develop five heuristic methods, including extensions of the classical largest gap, mid point, S-shape, and combined heuristics. The fifth one is an implementation of the powerful adaptive large neighborhood search algorithm specifically designed for the problem at hand. We then implement a branch-and-cut algorithm and cutting planes to solve the two formulations. The performance of the proposed solution methods is assessed on a newly generated and realistic test bed containing up to 100 pickups and seven aisles. We compare the bounds provided by the two formulations. Our in-depth analysis shows which formulation tends to perform better. Extensive computational experiments confirm the efficiency of the ALNS matheuristic and derive some important insights for managing order picking in this kind of warehouses

Les services intensifs : une nouvelle approche dans l’intervention auprès des familles à risque

L'augmentation du nombre de placements d'enfants et l'échec relatif de cette mesure dans le traitement des problèmes familiaux amènent les professionnels des services sociaux à réfléchir sur de nouvelles façons d'aider les familles à résoudre leurs difficultés tout en maintenant l'unité familiale intacte. Les services intensifs à la famille appartiennent à ce courant de renouveau. Le présent article décrit cette nouvelle forme d'intervention. Plus précisément, trois grands thèmes sont abordés. Le premier porte sur l'historique de ces programmes, leur philosophie et leurs principes, de même que sur les trois principaux modèles mis en oeuvre sous le vocable des services intensifs à la famille, soit les programmes Homebuilders, Familieset Family Treatment. Dans un second temps, l'efficacité des programmes de sauvegarde de la famille est examinée en apportant une attention particulière aux problèmes méthodologiques que soulève leur évaluation. L'article se termine par une présentation des conditions nécessaires à l'implantation de ces programmes dans les services sociaux québécois

Mathematical models for the warehouse reassignment problem

For several decades, researchers have developed optimization techniques forwarehouse operations. These techniques are related in particular to the materialhandling, the order picking and storage assignment strategies for a myriad of warehouse configurations. It is often neglected that these strategies need to be regularlyadjusted in order to adapt to changes in technology, in the demand and/or product offers. Most research on storage assignment provide excellent methods to determine where products should be located. However, the handling part of the problem is often set aside. Moving from one setup to another requires a large amount of work and disturbs regular order-picking operations. This chapter presents the warehouse reassignment problem in order to minimize the total workload to reassign the products to their new locations. We demonstrate how one can move from an out-of-date storage assignment to a better one, in a minimum of working time. We introduce three different mathematical formulations and compare them through extensive computational experiments in order to identify the best one.<br/

Mathematical models for the warehouse reassignment problem

For several decades, researchers have developed optimization techniques forwarehouse operations. These techniques are related in particular to the materialhandling, the order picking and storage assignment strategies for a myriad of warehouse configurations. It is often neglected that these strategies need to be regularlyadjusted in order to adapt to changes in technology, in the demand and/or product offers. Most research on storage assignment provide excellent methods to determine where products should be located. However, the handling part of the problem is often set aside. Moving from one setup to another requires a large amount of work and disturbs regular order-picking operations. This chapter presents the warehouse reassignment problem in order to minimize the total workload to reassign the products to their new locations. We demonstrate how one can move from an out-of-date storage assignment to a better one, in a minimum of working time. We introduce three different mathematical formulations and compare them through extensive computational experiments in order to identify the best one.<br/

Service level, cost and environmental optimization of collaborative transportation

Less than truckload is an important type of road-based transportation. Based on real data and on a collaboration with industry, we show that a collaborative approach between companies offers important benefits. We propose to develop partnerships between shipping companies and to synchronize their shipments. Four operational collaborative schemes with different objectives are developed. The first one focuses on minimizing shipping costs for shippers. The second and third ones minimize the carrier’s costs and the environmental cost, respectively. The fourth one is a combination of all three. The results of our computational experiments demonstrate that collaboration lead to significant cost reductions