Aicha Aguezzoul

A nonlinear multiobjective approach for the supplier selection, integrating transportation policies

Purpose – The impact of transportation on the supplier selection has received very scant attention in the literature. This is a great limitation because splitting orders across multiple suppliers will lead to smaller transportation quantities which will likely imply larger transportation cost. Moreover, transportation and inventory elements are highly interrelated and contribute most to the total logistics costs. This paper seeks to present a nonlinear multiobjective programming approach of selecting suppliers and allocating the order quantity among them, taking into account transportation.Design/methodology/approach – The model considers the total product cost and the lead‐time as the criteria to minimize simultaneously.Findings – The total cost is the sum of transportation, inventory and ordering costs. The constraints related to suppliers and buyer are also considered in the model. The model is solved several times, evaluating various scenarios. Each scenario depends on the shipment type used between t...

A preliminary analysis on Lean Six Sigma application in healthcare

Nowadays, the provisions of healthcare are selected for their quality. Hospitals have begun intensely to use one of concept of ISO 9001: “The customer voice”, which consists on using the perception of patients to organize their services and improve their global performance. The implementation of Lean Six Sigma (L6S) approach helps to achieve this goal. This approach corresponds to the merger of two quality improvement: Lean and 6 Sigma. Both methods encompass a number of principles and tools designed to increase process efficiency by reducing wasteful steps. This paper presents an application of L6S approach in the hospital sector by focusing on the need to implement this tool to improve the value chain of healthcare, and the KPIs used.

Optimization of integrated preventive maintenance based on infinitesimal perturbation analysis

A strategy combining preventive maintenance and production control is proposed.Gradient estimates with respect to each decision variable are determined via IPA.IPA has not been used to find the optimal preventive maintenance period as proposed.Gradients based on the sample paths are integrated in a simulation algorithm.Transfer and transportation delays are considered explicitly in this model. This paper considers jointly the production control and preventive maintenance problem in a manufacturing system. This system is composed of a single unreliable machine that produces one or two types of products with constant and different demand, a customer and a buffer between the machine and the customer. Machine failures are time-dependent, i.e. the machine can fail at any time, so a block-type preventive maintenance policy is proposed to increase the system life. This policy is coupled with a hedging point policy which controls the machine production speed. Between each element of the system, constant transportation delays are considered, i.e. a conveyor between the machine and its downstream buffer and a transport between the buffer and the customer. Then, a continuous-flow model is proposed to represent the overall dynamics of the system. This model allows us to take into account explicitly the transportation delays. The main objective of this work is to find the optimal preventive maintenance period by means of infinitesimal perturbation analysis technique as well as the optimal hedging point in order to minimize the expected average cost function. For this, we find the gradient estimators of the cost function from a theoretical sample path study. Then we integrate them in a simulation algorithm to find a numerical estimation of the solution. Simulation results highlight our theoretical results.

Performance Evaluation of Preventive Maintenance Considering Transportation Delays

Abstract This paper considers a production system of a single product, with constant transportation delays of items, between the machine and the buffer and between the buffer and the customer. The demand arrives with a constant rate. The system is modeled by a continuous-flow model. The machine is subject to time-dependent failures and the piloting policy is of hedging point type. We employed a preventive maintenance policy that is realized at each certain period. A performance evaluation of the system is made by simulation.

Direct or indirect delivery in multiple sourcing strategy: A lexicographic model

The decision of supplier selection is strategic because it impacts the total performance of the company. A literature review on this field shows that studies that explicitly consider the impact of direct or indirect delivery on this decision are scarce. In this paper, a multi-objective programming model, based on lexicographic method, is proposed to simultaneously determine the optimal number of suppliers to employ and the order quantities to allocate to them, taking into account the transportation policies. The objectives to minimize are total logistics cost and leadtime, under suppliers, buyer and transportation constraints. A comprehensive example is provided to illustrate the model.

Supplier selection under purchasing and transportation conditions

Abstract Little attention is given in the literature to the transportation impact on the supplier selection decision. In this paper, we propose a mixed nonlinear programming model to simultaneously determine the optimal number of suppliers to employ and the order quantities to allocate to them, taking into account the transportation. The objective of the model is to minimize the total cost, which includes purchasing, transportation, ordering and inventory costs subject to suppliers, buyer and transportation constraints. The model is solved several times, evaluating various scenarios. Each scenario depends on the shipment type used between the suppliers and the buyer.

3PL performance evaluation and selection: : a MCDM method

ABSTRACT Third-party logistics (3PL) performance evaluation and selection is a strategic decision and a complex process that involves various qualitative and quantitative criteria. In this article, a multi-criteria decision-making (MCDM) tool based on ELECTRE I method is developed and applied to this process. This tool allows constructing a partial ranking, choosing a set promising 3PL and making the sensitivity analysis by varying the main parameters. An example of a real case is implemented to demonstrate the practicability of the proposed method.

The Impact of Transportation Network on the Supplier Selection

Abstract Supplier selection decision is largely studied in the literature but little attention is given to the transportation aspect in this decision. In this paper, a multi-objective programming model, based on lexicographic method, is proposed to simultaneously determine the optimal number of suppliers to employ and the order quantities to allocate to them, taking into account the transportation policies. The product bought from supplier can be shipped directly or via consolidation terminal to the buyer. The objectives to minimize in the model are total logistics cost and lead-time, under suppliers, buyer and transportation constraints. A comprehensive example is provided to illustrate the model.

Overview on supplier selection of goods versus 3PL selection

The selection and the evaluation of suppliers of goods or services is a strategic purchasing decision that affects the total performance of every company. That decision is a multicriteria problem and a complex process that requires the use of multiple quantitative and qualitative criteria, often in conflict. It is widely studied in the literature related to supply chain design/management, agile manufacturing, dynamic alliances, and purchasing management. The aim of this paper is to present a comparative study between the selection of suppliers of goods and that of suppliers of services such as the logistics services, in terms of criteria and methods.