135 research outputs found
Inventory Management and Demand Forecasting Improvement of a Forecasting Model Based on Artificial Neural Networks
Forecasting is predicting or estimating a future event or trend. Supply chains have been constantly growing in most countries ever since the industrial revolution of the 18th century. As the competitiveness between supply chains intensifies day by day, companies are shifting their focus to predictive analytics techniques to minimize costs and boost productivity and profits. Excessive inventory (overstock) and stock outs are very significant issues for suppliers. Excessive inventory levels can lead to loss of revenue because the company's capital is tied up in excess inventory. Excess inventory can also lead to increased storage, insurance costs and labor as well as lower and degraded quality based on the nature of the product. Shortages or out of stock can lead to lost sales and a decline in customer contentment and loyalty to the store. If clients are unable to find the right products on the shelves, they may switch to another vendor or purchase alternative items. Demand forecasting is valuable for planning, scheduling and improving the coordination of all supply chain activities. This paper discusses the use of neural networks for seasonal time series forecasting. Our objective is to evaluate the contribution of the correct choice of the transfer function by proposing a new form of the transfer function to improve the quality of the forecast
A Study on an Extensive Hierarchical Model for Demand Forecasting of Automobile Components
Demand forecasting and big data analytics in supply chain management are gaining interest. This is attributed to the wide range of big data analytics in supply chain management, in addition to demand forecasting, and behavioral analysis. In this article, we studied the application of big data analytics forecasting in supply chain demand forecasting in the automotive parts industry to propose classifications of these applications, identify gaps, and provide ideas for future research. Algorithms will then be classified and then applied in supply chain management such as neural networks, k-nearest neighbors, time series forecasting, clustering, regression analysis, support vector regression and support vector machines. An extensive hierarchical model for short-term auto parts demand assessment was employed to avoid the shortcomings of the earlier models and to close the gap that regarded mainly a single time series. The concept of extensive relevance assessment was proposed, and subsequently methods to reflect the relevance of automotive demand factors were discussed. Using a wide range of skills, the factors and cofactors are expressed in the form of a correlation characteristic matrix to ensure the degree of influence of each factor on the demand for automotive components. Then, it is compared with the existing data and predicted the short-term historical data. The result proved the predictive error is less than 6%, which supports the validity of the prediction method. This research offers the basis for the macroeconomic regulation of the government and the production of auto parts manufacturers
Modeling and Solving a Linear Integer Problem (PLNE) for the Optimal Localization of a Hub Air Transport in the WAEMU Zone
In this article, we propose a linear integer model for the optimal location of a hub for air traffic in the WAEMU zone. A hub represents for an airline a base where an essential part of its activities is concentrated. Its location must therefore be judiciously determined. The hub location problem is one of the new and promising areas of research in the field of location theory. In order to satisfy a demand, the location of the hub involves the movement of people, goods between origin destination pairs required. Hubs are applied to reduce the number of transport links between the origin and destination airports. The proposed model minimizes the distances and takes into account the flow of passengers registered in the different airports and minimizes the total cost of the transfer via the hub airport. The simulations were made with the programming language Python
Modeling and Solving a Linear Integer Problem (PLNE) for the Optimal Localization of a Hub Air Transport in the WAEMU Zone
In this article, we propose a linear integer model for the optimal location of a hub for air traffic in the WAEMU zone. A hub represents for an airline a base where an essential part of its activities is concentrated. Its location must therefore be judiciously determined. The hub location problem is one of the new and promising areas of research in the field of location theory. In order to satisfy a demand, the location of the hub involves the movement of people, goods between origin destination pairs required. Hubs are applied to reduce the number of transport links between the origin and destination airports The proposed model minimizes the distances and takes into account the flow of passengers registered in the different airports and minimizes the total cost of the transfer via the hub airport. The simulations were made with the programming language Python
Laparoscopic Appendectomy in Children: Preliminary Study in Pediatric Hospital Albert Royer, Dakar
Appendiceal pathology’s management has benefited in recent years from the advent of laparoscopic surgery. This study is to make a preliminary assessment of laparoscopic management of acute and complicated appendicitis in children after a few months of practice at the University Hospital Albert Royer, Dakar. This is a retrospective study of 22 cases of patients, all operated on by the same surgeon. The parameters studied were age, sex, clinical data and laboratory features, radiological data, and results of surgical treatment. The mean age of patients was 9.5 years with a male predominance. The series includes 14 cases of acute appendicitis and 8 complicated cases. Appendectomy anterograde is practiced in 81% of cases. Appendectomy was associated with peritoneal wash in 17 patients including 9 cases of acute appendicitis. Drainage of Douglas pouch is performed in 2 patients with complicated appendicitis; the average production was 300 cc of turbid liquids and any complications were not founded. An abscess of Douglas pouch is noted in 2 patients with complicated appendicitis undrained. These Douglas abscesses were treated medically. No conversion of laparotomy was performed in the series. After an average of 8 months no other problems were noted
Mise en œuvre d'un solveur direct parallèle pour l'inversion des problèmes locaux au sein d'une méthode de décomposition de domaine
National audienceLe but de ce papier est de mettre au point un algorithme parallèle pour la résolution directe de grands systèmes linéaires creux et l’intégrer dans les méthodes de décomposition de domaine. Ces systèmes linéaires, souvent rencontrés lor de la simulation numérique de problèmes de mécanique des structures par des codes de calcul par éléments finis, sont résolus avec des coûts très importants en temps ce calcul et en espace mémoire. Dans ce papier, un parallélisme à deux niveaux a été exploité. L’exploitation du niveau inférieur de parallélisme a d’abord consisté à réaliser un solveur direct parallèle basé sur une technique de dissection emboitée et l’intégrer ensuite dans les méthodes FETI. Ce solveur direct a l’avantage de traiter automatiquement et proprement les modes à énergie nulle dans des structures flottantes. L’exploitation du niveau supérieur a consisté à améliorer la phase itérative de la méthode FETI classique. Des tests ont été effectués pour évaluer les performances du solveur mis en place
Les Diatomées Sub-fossiles de L’estuaire du Saloum, Sénégal: inventaire floristique et paléo-environnement fournis par la carotte de Ndangane Babou
Dans le programme de reconstitution de l’histoire des estuaires et lagunes du Sénégal et de l’inventaire de la microflore à diatomées de la Séné-Gambie, une carotte de sondage de 400 cm de long a été réalisée à Ndangane Babou sur un des bras de l’estuaire du Saloum (14°07′53.86″ N/16°17′40.08″ W) à 95 km de l’embouchure. L’analyse comparée de la lithologie et de la microflore a montré une corrélation significative entre la fraction pélitique, l’abondance absolue des diatomées et leur diversité spécifique. Le faible taux de sable, majoritairement d’origine marine tout au long de la carotte pourrait s’expliquer par l’éloignement du site de prélèvement par rapport à l’embouchure du fleuve. L’étude a permis d’inventorier 89 espèces et variétés de diatomées appartenant à 48 genres. Les genres les plus représentés sont Nitzschia (11 espèces), Coscinodiscus (7 espèces), Amphora et Navicula (4 espèces chacune). Huit espèces sont citées pour la première fois en Séné-Gambie. La dominance des espèces euryhalines tout au long de la carotte ainsi que la présence constante des formes d’eau douce témoignent de variations de la salinité entre les saisons hivernales marquées par des apports d’eau douce et les saisons sèches. D’un milieu deltaïque ouvert aux influences marines (Zone A), le Saloum a été marqué par des upwellings qui ont apportés des sels nutritifs jusqu’à la hauteur de Ndangane Babou durant le dépôt de la zone B. Par la suite, l’installation d’un climat chaud et humide a entrainé une augmentation de la pluviométrie et permis d’atteindre une paléo-productivité primaire et une paléo-biodiversité maximales au sommet de la zone C, avant l’installation d’un climat aride à l’origine du caractère inverse de l’estuaire (zone D). Dans ce milieu, l’hydrodynamisme serait à l’origine de l’augmentation du taux de sable et corrélativement la diminution des diatomées suivie de leur disparition.
As part of the program to rebuilt the estuaries and lagoons history in Senegal and the inventory of the diatom microflora in Senegal and Gambia, a 400 cm long core was taken at Ndangane Babou on one of the arms from the Saloum estuary (14°07′53.86″ N/16°17′40.08″ W), 95 km from the ocean. The comparative analysis of the lithology and the microflora showed a significant correlation between the lutite fraction, the absolute abundance of diatoms and their specific diversity. The low rate of sand, mostly of marine origin throughout the core, could be explained by the distance of the site from the mouth of the estuary. The study allowed to inventory 89 species and varieties of diatom belonging to 48 genera. The most represented genera are Nitzschia (11 species), Coscinodiscus (7 species each), Amphora and Navicula (4 species each). Eight species are cited for the first time in Sene-Gambia. The dominance of euryhaline species throughout the core as well as the constant presence of freshwater forms attest to variations in salinity between the rainy seasons marked by freshwater inflows and the dry seasons. From a delta environment open to marine influences (Zone A), the Saloum estuary was marked by upwellings brought nutritive salts up to the height of Ndangane Babou during Zone B deposit. Subsequently, the installation of a hot and humid climate led to an improvement in rainfall and allowed to achieve maximum primary paleo-productivity and paleo-biodiversity at the top of zone C, before the installation of an arid climate at the origin of the opposite character of the estuary (zone D). In this environment, hydrodynamics would be the cause of the increase in the rate of sand and correlatively the decrease in diatoms followed by their disappearance
Lanthanide(III) complexes with tridentate Schiff base ligand, antioxidant activity and x-ray crystal structures of the Nd(III) and Sm(III) complexes
The tridentate N4-type Schiff base was synthesized from the condensation reaction of 2-hydrazinopyridine and pyridine-2-carbaldehyde. Neodymium and Samarium complexes were isolated when the corresponding nitrate salt was added to the solution of the ligand. The isolated compounds were characterized by elemental analyses, IR study, room temperature magnetic measurements and single X-ray crystal diffraction of the two crystals. Both complexes crystallize in the monoclinic system with space group P21/c. The cell parameters of the Nd complex are a=11.0927(8) Å, b=17.9926 (13) Å, c=11.9395(9)Å and β = 115.274(5) ° while the Sm complex shows parameters cell of a = 11.0477(8) Å, b = 17.9254(13) Å, c = 11.9149(8) Å and β =115.489(5) °. The X-ray study reveals isotopic Nd/Sm binuclear structures were each metal ion is nine-coordinated in the same fashion. Both metal centers have distorted tricapped trigonal prism geometry, with the Schiff base acting as tridentate ligand. The DPPH· radical scavenging effects of the Schiff base ligand and its Ln(III) complexes were screened. The Ln(III) complexes were significantly more efficient in quenching DPPH· than the free Schiff base ligand.Keywords: Lanthanide complexes, hydrazino, antioxidant activity, X-ray structur
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