Coping with uncertainties via resilient supply chain framework

Supply chain resilience (SCR) is a promising area budding from the emergent admiration to minimise supply chain disruptions by practitioners and by researchers across the globe. To inflate monetary earnings, many organisations execute initiatives such as comprehensive reach of supply chains, amplified outsourcing, shorter product life cycles, reduced buffers and centralisation. These initiatives are effective in stable surroundings, but they could make supply chain vulnerable to various types of disruptions. The main thrust of this research is, to propose a conceptual model for endowing deeper knowledge of how uncertainty from suppliers, customers and existing supply chain structure amplifies vulnerability and consequently increases supply chain risk exposure. In accordance with fitness landscape theory, this paper accepts a complex systems perspective to view supply chain organisations and understand their capabilities. It focuses on diminishing the vulnerability of supply chain systems and the ability to design systems to be more resilient to chang

Exploring the Impact of Network Structure and Demand Collaboration on the Dynamics of a Supply Chain Network Using a Robust Control Approach

A supply chain network might exhibit complex dynamics in the face of increasingly volatile and uncertain environment. The impact of network structure and collaboration on the dynamics and robustness of supply chain network, however, remains to be explored. In this paper, a unified state space model for a two-layer supply chain network composed of multiple distributors and multiple retailers is developed. A robust control algorithm is advocated to reduce both order and demand fluctuations for unknown demand. Numerical simulations demonstrate that the robust control approach has the advantage to reduce both inventory and order fluctuations. In the simulation experiment, it is interesting to notice that complex network structure and collaborations might contribute to the reduction of inventory and order oscillations. This paper yields new insights into the overestimated bullwhip effect problem and helps us understand the complexities of supply chain networks

The impact of the supply chain structure on bullwhip effect

The aim of this paper is to study how the structural factors of supply chain networks, (i.e. the number of echelons, the number of nodes and the distribution of links) impact on its dynamics performance (i.e. bullwhip effect). To do so, we systematically model multiple structures according to a robust design of experiments and simulate such structures under two different market demand scenarios. The former emulates a stationary condition of the market, while the latter reproduce the extreme volatility and impetuous alteration of the market produced by the current economic recession. Results contribute to the scientific debate on supply chain dynamics by showing how the advocated number of echelons is not the only structural factor that exacerbates the bullwhip effect. In particular, under a sudden shock in market demand, the number of nodes and the divergence of the supply chain network affect the supply chain performance.Ministerio de Economía y Competitividad DPI2013-44461-P/DP

A Representation of Tactical and Strategic Precursors of Supply Network Resilience Using Simulation Based Experiments

Modern supply chains are becoming increasingly complex and are exposed to higher levels of risk. Globalization, market uncertainty, mass customization, technological and innovation forces, among other factors, make supply networks more susceptible to disruptions (both those that are man-made and/or ones associated with natural events) that leave suppliers unavailable, shut-down facilities and entail lost capacity. Whereas several models for disruption management exist, there is a need for operational representations of concepts such as resilience that expand the practitioners’ understanding of the behavior of their supply chains. These representations must include not only specific characteristics of the firm’s supply network but also its tactical and strategic decisions (such as sourcing and product design). Furthermore, the representations should capture the impact those characteristics have on the performance of the network facing disruptions, thus providing operations managers with insights on what tactical and strategic decisions are most suitable for their specific supply networks (and product types) in the event of a disruption. This research uses Agent-Based Modeling and Simulation (ABMS) and an experimental set-up to develop a representation of the relationships between tactical and strategic decisions and their impact on the performance of multi-echelon networks under supply uncertainty. Two main questions are answered: 1) How do different tactical and strategic decisions give rise to resilience in a multi-echelon system?, and 2) What is the nature of the interactions between those factors, the network’s structure and its performance in the event of a disruption? Product design was found to have the most significant impact on the reliability (Perfect Order Fulfillment) for products with high degrees of componentization when dual sourcing is the chosen strategy. However, when it comes to network responsiveness (Order Fulfillment Cycle Time), this effect was attenuated. Generally, it was found that the expected individual impact these factors have on the network performance is affected by the interactions between them

サプライネットワークの挙動と構造に関する相互関係方策の共進効果の解析

広島大学(Hiroshima University)博士(工学)Doctor of Engineeringdoctora

The impact of supply chain structures on performance.

La Tesis analiza el impacto que tiene la estructura de las redes de suministro sobre su rendimiento, concretamente sobre el “efecto látigo” o efecto bullwhip. Para ello se desarrolla una arquitectura basada en la metodología de los sistemas multi-agente, que permite el modelado de sistemas complejos. Dicha arquitectura es implementada en un software dando lugar a un simulador de redes de suministro llamado SCOPE, que permite el modelado y simulación de una amplia variedad de configuraciones de redes de suministro. SCOPE es utilizado para investigar una de las suposiciones más comunes en el campo del modelado de redes de suministro: el uso de estructuras muy sencillas en forma serial generalmente con muy pocas fases funcionales y pocos nodos. Para determinar el impacto de la estructura de la red sobre el efecto bullwhip se utiliza una estructura más compleja y más acorde con las estructuras de redes de suministro reales: la red divergente. Se realizan tres experimentos: (i) análisis comparativo del efecto bullwhip entre la red divergente y la serial; (ii) análisis comparativo de la eficacia de dos técnicas muy conocidas para la limitación del efecto bullwhip entre la red divergente y la serial; (iii) determinación de los parámetros estructurales de la red de suministro divergente y análisis estadístico para determinar si dichos parámetros estructurales impactan sobre el efecto bullwhip. Los resultados obtenidos revelan que todos los parámetros estructurales analizados impactan significativamente sobre efecto bullwhip. Además, en caso de un impulso inesperado en la demanda, el impacto de la red de suministro en el efecto bullwhip es mayor. Las técnicas para limitación del efecto bullwhip son también efectivas en redes de suministro divergentes, consiguiendo además un aumento de su robustez ante cambios bruscos inesperados en la demanda

Leveraging supply network relationships to drive performance

Effective supply chain management requires focal firms to develop capabilities to manage a myriad of multi-tier, interconnected relationships often spanning multiple industries. Conventional assessments of supply chain relationships as linear or dyadic structures, rather than as a network, limit academician and managerial approaches to overcome challenges to effectively manage supply chains. Further, empirical research on innovation and performance implications of supply network structure and its corresponding relationship dynamics is still fairly nascent. My research focuses on leveraging supply network relationships to drive performance. Specifically, in my dissertation I examine how the structural, knowledge, and dependency differences in a firm’s supply network can affect knowledge and information flow, and ultimately the firm’s innovative, operational, and financial performance. My first study (CH. 2) contributes to current research at the interface of supply chain management and innovation. My second (CH. 3) and third paper (CH. 4) incorporate the intensity of each supply network link, reflective of focal firms as customers (suppliers) that may rely heavier on a supplier (customer) based on their percentage of cost (revenue) that goes to (is generated from) that supplier (customer). All three papers extend current research findings by bringing a more holistic assessment of firms that are embedded in a supply network, addressing the need for deeper structural analysis.Ph.D

Information assurance within supply chains’ structures and processes.

Doctoral degree. University of KwaZulu-Natal, Durban.Organisations are challenging the traditional linear-based market model which is characterised by a straight line movement of goods and services. As a result, they are increasingly forming and moving towards a value web of supply chain network that connects a whole ecosystem of trading partners. These networks, which are mostly complex and dynamic, are creating a global market environment in which organisations no longer focus only on their immediate suppliers and customers, but also on the optimization and the smooth flow of information, funds and materials, within their respective direct and remote trading networks. The large number of participants within most supply chain networks has necessitated that these networks be agile and resilient. For supply chain networks to be agile and resilient, and for supply chains’ structures, processes and resources to be synchronized and integrated, the organisations within the supply chain must share information. Hence, in today’s supply chains, interests are moving towards obtaining the most benefits from information. In order to obtain these benefits from information, organisations are making use of information systems and their related technologies to acquire, process and adequately share information. These systems are making it possible for organisations to form strategic partnerships within the supply chain networks. The global market environment is causing supply chains to expand, and the expansion is exposing information to various security vulnerabilities and risks. The exposure of information to different vulnerabilities and risks is forcing trading partners to seek assurance that the information within their supply chain network is adequately protected and also performs as advertised. To understand how the assurance sought by trading partners can be provided, this study investigated information and information systems’ security within supply chains’ structures and processes. The study also investigated how information assurance objectives (i.e. confidentiality, integrity, availability, authentication and non-repudiation) can be achieved optimally within supply chains. Finally, the study proposes an information assurance model, which if adopted by decision makers, could enable them sustain their respective functions and processes within the supply chain network. In order to achieve the objectives of this study, the exploratory design and the case study approach were adopted in this study. The study also adopted the qualitative research method, and hence, semi-structured interviews were conducted, and served as the primary means of data collection. Participants in this study were drawn from two categories of organisations, which are supply chain and logistics organisations, and Information Technology (IT) consulting organisations. Therefore, the purposive sampling method was adopted in this study. An inductive approach was adopted in the analysis of data, and as a result, thematic analysis was adopted as the analysis method. The main outcome of the study is the proposed information assurance model that can enable decision makers sustain their respective functions and processes within the supply chain network

Human factors : a new approach for designing the truck-driver system

The logistics sector is an often forgotten force behind modern life in the UK, and it is increasingly under pressure to become more efficient, more safety-conscious, and more environmentally sustainable. This triple bottom line necessitates deep changes to the traditional way of working. As evidenced by an expert-led technology forecast, many technological and organisational interventions are on the horizon for the next 15-30 years. This rapid pace of advancement, together with the frequent assumption that workers are ‘hyper-rational’, echoes a worrying pattern from other sectors that have since benefited from human factors & ergonomics (HF/E) expertise. This thesis aims to apply HF/E principles and methods to both current and projected future truck-driver scenarios, in order to leverage the most agile and intelligent agent in the logistics system: the human. Despite a lack of past work at this intersection, logistics and HF/E can be drawn together by their mutual use of systems complexity concepts. This thesis proposes that logistics is a large, complex adaptive socio-technical system (CASTS), and reviews HF/E methods to determine their fit to different system scales and dynamics. From this it is determined that initial work requires a bottom-up focus on the truck-driver system. A range of methods are employed to understand the existing truck driving task and what it requires of the modern driver; identify and prioritise potentially critical system ‘parts’; design new supportive technologies from scratch in a way that allows for emergent behaviour; and analytically prototype how truck-driver systems are likely to change in projected future scenarios. This work provides new practical insights for current truck-driver systems, and a map of how this may change – shedding light on potential future problems and how we might adapt to them before they occur. Not only does this thesis provide a solid empirical foundation and a ‘direction of travel’, it also contributes the methodological guidance necessary to strategise next steps beyond this thesis, into deeper logistics complexity. Taken together this demonstrates the power of human factors methods for logistics, and their potential for other unexplored ‘complex adaptive sociotechnical systems’ (CASTS)