Amr Mahfouz

Practical simulation application: Evaluation of process control parameters in Twisted-Pair Cables manufacturing system

Intensive competition and rapid technology development of Twisted-Pair Cables (TPC) industry have left no room for competing manufacturers to harbour system inefficiencies. TPC are used in various communication and networks hardware applications; their manufacturing facilities face many challenges including various product configurations with different equipment settings, different product flows and Work in Process (WIP) space limitations. The quest for internal efficiency and external effectiveness forces companies to align their internal settings and resources with external requirements/orders, or in different words, significant factors must be set appropriately and identified prior to manufacturing processes. Integrated definition models (IDEF0, IDEF3) in conjunction with a simulation model and a design of experiments (DOE) have been developed to characterize the TPC production system, identify the significant process parameters and examine various production setting scenarios aiming to get the best product flow time.

Analysing supply chain resilience: integrating the constructs in a concept mapping framework via a systematic literature review

Purpose The purpose of this paper is to analyse the concept of supply chain resilience (SCRES) within a concept mapping framework to seek conceptual clarity, with an emphasis on SCRES definitions, essential elements and managerial practices. Design/methodology/approach A systematic literature review was conducted of 103 peer-reviewed journal articles from the year 2000 to 2015, with the aim of answering a focus review question. Findings Through analysis and synthesis of the literature, the study revealed three major constructs used to define SCRES: phases of resilience, resilience strategies and the capabilities needed to be resilient. Emerging from the capabilities construct are five core SCRES capabilities: the ability to anticipate, to adapt, to respond, to recover and to learn. Also, given the need to consolidate the various constructs of SCRES, the study identified 13 essential elements and 84 managerial practices that support firms to achieve the five capabilities, which are then linked to SCRES strategies and phases to establish the connections that provide an integrated view of the concept. Research limitations/implications The explorative nature of this study and the role of the concept mapping framework, which does not empirically test the relationships in the model, are considered as limitations, to be addressed by the authors in future research. Originality/value The originality of this paper lies in the classification of different features of SCRES through a comprehensive concept mapping framework that establishes relationships and interactions between them. This study, therefore, lays a foundation for testing these connections in future empirical studies. The paper brings together fragmented literature from multiple studies to create a solid body of knowledge that addresses the need for conceptual clarity in SCRES literature.

Simulation based optimisation model for the lean assessment in SME: a case study

Due to their space limitation and small production scale, small and medium enterprises (SME) are vulnerable to rapid changes. Lean principles are considered as effective improvement approach to eliminate systems waste and inefficiencies. Although much of the academic materials have addressed the lean practices into large, global companies, they can still be adjusted to SMEs. Risks are usually associated with lean implementation process due to the drastic required changes in business policies and operations. Simulation can be successfully used to predict the impact of the proposed changes ahead of the implementation which helps to mitigate risks. Integrating simulation with optimization techniques provides optimum set-tings of the lean factors prior to the go live stage. In this study, simulation based optimization model was developed to optimize a set of parameters of lean SME against three performance measures - cycle time, WIP (work in process) and workforce utilization. Results showed constructive insights.

Integrating Current State and Future State Value Stream Mapping with Discrete Event Simulation: A Lean Distribution Case Study

Abstract: In response operations to global recession and increased competition, organizations have tried to become more efficient by decreasing costs and streamlining operations. To achieve this, the philosophy of lean management has gained in popularity. The main obstacle organizations face when implementing lean is deciding which activities to implement lean principals on. A well known lean practice, value stream mapping, is a very effective tool in mapping the current and future state of an organizations lean activities. Limitations in calculating variability information that describe system variations and uncertainty means more powerful analytical tools are needed. Simulation offers a more thorough analysis of a system’s data , including the examination of variability and has the ability to change certain parameters and measure key lean performance indicators. Using a tire distribution company as a case study, this paper has developed a framework that uses discrete event simulation as an integrative layer between current and future value stream mapping. The framework maps current state value and non-value activities in the company and through simulation has highlighted the activities that should be used when developing the future state map. This paper has highlighted simulation as a crucial middle layer in value stream mapping that will generate more accurate future state maps than the more common practices of using random estimates and experience alone.

Customer Management Analysis of Irish Plumbing & Heating Distribution System: A Simulation Study

The sudden burst of the property bubble, coupled with current global economic conditions has resulted in a huge decrease in demand for plumbing and heating fixtures in the Irish construction industry. Moreover, inefficient supply chain management policies have imposed further pressures on companies resulting in more system bottlenecks and unnecessary costs. Inventory management is seen as a functional area that can ease such bottlenecks and in turn increase supply chain efficiency, decrease costs and increase customer satisfaction. The challenge is to predict the balance of on-hand inventory and order quantity to optimise customer satisfaction and minimise inventory cost. It is also essential that managers clearly understand the cost effect stock-outs have on different groups of customer, i.e. customer segmentation policy. Traditional inventory mathematical techniques are inadequate in investigating the influence of customer segmentation policy on performance. To investigate this further, conceptual modelling using flowcharts and data flow diagrams in conjunction with simulation modelling and design of experiments have been developed to characterise the inventory management process of a plumbing and heating distribution centre. Significant process parameters where identified and examined with and without segmented customer management policies, aiming to achieve a high level of customer satisfaction rate at the lowest possible total cost.

The Analysis of Rush Orders Risk in Supply Chain: A Simulation Approach

Satisfying customers by delivering demands at agreed time, with competitive prices, and in satisfactory quality level are crucial requirements for supply chain survival. Incidence of risks in supply chain often causes sudden disruptions in the processes and consequently leads to customers losing their trust in a companys competence. Rush orders are considered to be one of the main types of supply chain risks due to their negative impact on the overall performance, Using integrated definition modeling approaches (i.e. IDEF0 & IDEF3) and simulation modeling technique, a comprehensive integrated model has been developed to assess rush order risks and examine two risk mitigation strategies. Detailed functions sequence and objects flow were conceptually modeled to reflect on macro and micro levels of the studied supply chain. Discrete event simulation models were then developed to assess and investigate the mitigation strategies of rush order risks, the objective of this is to minimize order cycle time and cost.

Hybrid modeling for vineyard harvesting operations

Hiring workers under seasonal recruiting contracts causes significant variation of workers skills in the vineyards. This leads to inconsistent workers performance, reduction in harvesting efficiency, and increasing in grape losses rates. The objective of this research is to investigate how the variation in workers experience could impact vineyard harvesting productivity and operational cost. The complexity of the problem means that it is difficult to analyze the system parameters and their relationships using individual analytical model. Hence, a hybrid model integrating discrete event simulation (DES) and agent based modeling (ABM) is developed and applied on a vineyard to achieve research objective. DES models harvesting operation and simulates process performance, while ABM addresses the seasonal workers heterogeneous characteristics, particularly experience variations and disparity of working days in the vineyard. The model is used to evaluate two seasonal recruiting policies against vineyard productivity, grape losses quantities, and total operational cost.

An Integrative Lean Assessment Model for Distribution Centres.

It is hard to benefit fully from lean manufacturing without having an efficient distribution centre. Applying lean distribution concept helps to reduce distribution centres waste while maintains customer service level high. The purpose of this study is to develop a lean assessment model that enables distribution managers to measure and improve the leanness levels of their companies. A data driven analytical approach (i.e. factor analysis) is used to assess leanness quantitatively. A lean index score is calculated to benchmark the leanness level of four distribution companies based in Ireland and UK. Results recommend that special attention should be taken on simplifying distribution network structure, establishing long term suppliers’ collaboration, managing customer demand, improving storage space utilisation, and managing distribution operations more efficiently.

Lean Distribution Concept, Constructs and Practices

In today’s competitive market, applying lean thinking provides supply chain the ability to produce and deliver products in a timely and cost effective manner. To date, little research addressed lean distribution concept as an effective approach for improving supply chains. This caused a level of ambiguity regarding the concept’s dimensional structure and its practices. This paper aims to explore the antecedents of lean distribution concept and identify its constructs and practices using a data driven analytical approach (i.e. exploratory factor analysis). Findings show that enhancing communication with customers, optimising transportation activity, people participating in problem solving procedures and increasing the reliability of distribution operations are critical dimensions of lean distribution paradigm.

Seaport Management Aspects and Perspectives: an Overview

Ireland occupies the northern part of the western European coast which has a 70,000 Kilometres coasting along two oceans and four seas. These coasts are Europe’s lifeblood and represent the trade routes, climate regulator and source of food, energy and resources. Seaports and shipping are key maritime activities which allow European coast countries to benefit from the rapid growth of international trade. Therefore, port management became the centre of governments’ interest and the focal point of research to improve the efficiency. This research aims to summaries past publications of seaport systems to highlight challenges and reveal relevant research gaps. Having the objective to classify the literature, a comprehensive review of journal articles and the best practices in the field was conducted. A wide variety of management issues and opportunities to improve service delivery of port systems was discussed in a three main categories based on port authority objectives; strategic, economic and operational.