Energy management in manufacturing: From literature review to a conceptual framework

The literature on energy management in manufacturing is rapidly growing. Since the literature is also quite fragmented, we believe that the time has come to delve into current knowledge in the research field to provide directions for policy makers and guidance for future research. To achieve this, we present a detailed analysis of the research literature on energy management in manufacturing, now encompassing 365 articles published from 1995 to 2015 in a variety of academic journals. Six main lines of research related to energy management appear in the area of the study: (i) drivers and barriers, (ii) information and communication technologies, (iii) strategic paradigms, (iv) supporting tools and methods, (v) manufacturing process paradigms, and (vi) manufacturing performances in the trade-off. Thus, a framework is derived inductively based on a comprehensive and systematic analysis of the literature to describe the dynamic process of energy management in manufacturing. The review and the proposed framework might be useful for both academicians and practitioners, as the study raises central theoretical and managerial questions as well as providing suggestions for further research on this important yet complex topic. (C) 2016 Elsevier Ltd. All rights reserved.

Operational Decisions and Supply Chain Dynamics

Olov Isaksson

While traditional research in operations management has focused on mathematical models for improving the flow of physical goods and information, this dissertation takes a quantitative empirical approach. With three distinct research projects it revisits central topics in the field and explores how operational decisions affect the performance of the firm and its trading partners. Chapter 2 examines the financial consequences that inventory leanness has on firm performance. We conduct an econometric analysis using 4,324 publicly traded U.S. manufacturing companies for the period 1980-2008. Using an instrumental variable fixed effects estimator we find a nonlinear relationship between inventory leanness and financial performance. However, we note that the maximum point of this inverted U-shaped relationship often lies at the extreme end of the investigated sample—suggesting a decreasing return from leanness rather than an optimal level. We show that the strength of this relationship is highly dependent on both industry and inventory type (raw materials, work in process and finished goods). The main novelty and direct implication of our findings is that most firms still have much potential to increase profitability by becoming leaner and they are unlikely to cross a threshold where profitability decreases with increased leanness. We display how much the average firm could gain by becoming leaner and show how this sensitivity changes by inventory component and industry. Finally, we highlight several new econometric aspects that we believe must be addressed when empirically investigating the inventory-performance link. The bullwhip effect is said to occur when demand variability is amplified from a downstream site (buyer) to an upstream site (supplier) in the supply chain. Chapter 3 contributes to the literature that empirically investigates the bullwhip effect by providing new evidence regarding its prevalence and magnitude. In contrast to previous work, we use a two-echelon approach, which allows us to observe varia- tions at both the upstream and the downstream sites. By drawing on a financial accounting standard regarding information disclosure about major customers, we are able to link 5,494 buyers-supplier dyads between 1976 and 2009. We merge this information with quarterly financial accounting data to form a sample of 14,933 buyer-supplier dyad observations. We correct for sample selection bias using propensity score matching and estimate the average bullwhip effect in our sample to 1.90 (i.e. 90% demand variability amplification between echelons). A significant bullwhip effect is found across industries (mining, manufacturing, wholesale and retail) and is supported by several robustness checks. We investigate and discuss how these results can be generalized beyond our sample. Chapter 4 explores knowledge spillovers in the supply chain. By building on the organizational learning literature we discuss how knowledge is diffused in the supply chain. Buyers-supplier relationship data is merged with financial accounting data, patent data and publication data to create a sample of 974 buyer-supplier dyad observations in the high tech industries. Using fixed effects estimation we show that a 1% increase in patent intensity at the buyers, on average leads to a 1% increase in patent intensity at the supplier. We find that the duration of the buyer-supplier relationship positively moderates this effect, but that the supplier’s sales dependency on the buyer has a negative moderating role. The technological proximity of the two firms, however, is not found to have a significant effect on spillovers. We discuss the implications of our findings for individual firms and theory.

EPFL2013

Towards Seamless Continuation of Knowledge in Product Lifecycle Management

Apostolos Perdikakis

The current ICT for manufacturing landscape is characterized by scattered data formats, tools and processes dedicated to different phases in the product lifecycle. Due to the diversity of tools and data formats, manufacturing struggles to cope with new trends in this area. What is clearly missing in the current ICT landscape for manufacturing is an integrated, holistic view on data about products to be manufactured, resources (including human resources) and processes across the full product lifecycle. There is a need to formalize knowledge for the automatic integration in existing engineering tools. In this work ontology-based semantics were exploited to develop machine-understandable models, which are able to understand the meaning of the data and information they contain. The system developed using semantic web methods and tools is designed to support interoperability and data integration, as well as lead a way towards the usage of information contained in the system to extract useful knowledge. This knowledge may provide feedback for improving the design of future generations of products. Thus, the concept of seamless continuation of knowledge all along product-system lifecycles is introduced.The first step of this work was to study the state-of-the-art in PLM and Semantic web Technologies. This included theoretical background in concepts like Beginning Of Life (BOL), Middle Of Life (MOL) and End Of Life (EOL) regarding PLM as well as the definition and theoretical background of Ontologies and Semantic Web Technologies. After completing the study of theoretical background, more advanced research concepts and methodologies for both domains were thoroughly analysed. Examples include Closed Loop Lifecycle Management (CL2M) for PLM and NEON Method-ology for Ontology engineering. The next logical step followed was to find and discover relevant standards like STEP for PLM and W3C standards for Ontologies and Semantic Web Technologies. The engineering aspect of this study imposed the review of available tools both for PLM and Ontology Engineering. Ontology development tools like Protégé, TopBraid composer and Anzo Ontology editor were studied. More advanced software solutions for applications of the semantic web were also studied. Examples include Anzo Enterprise and the Open Semantic Framework. Inspiration also came from previous European projects like EC FP6 Promise. The problem of discontinuation, even after an Ontology model is created, is evident in most of the applications studied as background of this work. Ontology models have to be exploitable and that requires a framework of which they can be part of. The research for successful implementations of ontology driven frameworks was imperative. At first, the open seman-tic framework (osf) was the software stack that came into focus. After being thoroughly studied, it proved difficult to deploy and maintain, for it had still many problematic areas with its configuration and required people with very ad-vanced software skills (both in programing and system configuration). Nevertheless, the examples of use are promis-ing and give many ideas for exploitation. This finding triggered the efforts towards the definition and application of the solution proposed in this work, which has the following characteristics. First and most important, the solution is easy to deploy and maintain, since it is targeting SMEs and large enterprises that want to test the capabilities of the proposed[...]

EPFL2015

Virtual metrology as an approach for product quality estimation in Industry 4.0: a systematic review and integrative conceptual framework

Gökan May

Virtual metrology (VM) involves estimating a product's quality directly from production process data without physically measuring it. This enables the product quality of each unit of production to be monitored in real time, while preserving the process efficiency. Initially developed for the semiconductor industry, VM has recently been examined for use in other industrial fields. VM is enabled by components such as quality estimators and drift detectors. It enhances various industrial applications such as machine control and sampling decision systems. The literature lacks a comprehensive summary and a systematic review of the state of the art in VM. To fill this gap, this study followed a systematic methodology to conduct a complete and structured literature review of VM. This paper presents a detailed analysis of the 199 papers that we identified based on our search and selection criteria. Following our methodological framework, we assigned these papers to categories and highlighted shortcomings. Finally, we discussed VM's use in various industrial fields, underlining its potential for every manufacturing industry. This study and the proposed framework are useful for both practitioners and academicians since they raise crucial theoretical and managerial questions as well as provide suggestions for further research on this critical topic.