PhD, DBA, and MSc by research theses (SoM)
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Browsing PhD, DBA, and MSc by research theses (SoM) by Author "Aktas, Emel"
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Item Open Access The effects of supply chain disruptions due to hurricanes on stock price.(Cranfield University, 2022-04) Schelp, Priscilla; Skipworth, Heather; Aktas, EmelPurpose and Rationale: It is known that supply chain disruptions have a negative stock price effect and that the effect is stronger if these are caused by catastrophes. However, these effects of hurricane-induced supply chain disruptions on stock price remain unexplored, even though the annual average hurricane damage in the US due to hurricanes is $54bn, of which $9bn is to commercial businesses. This thesis aims to: 1. Explore, classify and connect the three concepts of natural disasters, supply chain disruption (SCD) and firm financial performance in one framework. 2. Identify potentially influencing factors and test if, and in which way, these influence the effect of hurricanes on stock price. 3. Define a statistical model to evaluate the effect of hurricanes on stock price. The main focus is on manufacturing firms. Design/Methodology/Approach: This research is quantitative. The daily closing value of 625 manufacturing companies that were listed on the NYSE between 2014 and 2018 was analysed. Autoregressive Integrated Moving Average (ARIMA) was applied in combination with intervention analysis to model the stock price time series. In total six deduced hypotheses were tested. The statistical interruptions in stock prices due to hurricane announcements and hurricane incident announcements were investigated. The method allowed estimation of the magnitude and temporal patterns of change by applying transfer functions. Multiple factors that potentially influence the magnitude or pattern of the stock price reaction were tested, including details of damage. Findings: Both hurricane incident announcements and hurricane announcements negatively affect a firm’s stock price, mostly in the form of a transitory change. Industry moderates the stock price reaction to hurricane announcements. Minor supply chain disruptions are the only impacts resulting in a positive reaction. Providing details on actual damage leads to less negative and mostly positive reactions. Companies providing information on preventive closures are unlikely to suffer a negative reaction. Practical Implications: Hurricane risk needs to be actively managed by firms in all sectors; however, the preparation needs to be sector-specific. Firms should focus their efforts on managing supply chain disruptions. Additionally, firms need to communicate in a transparent way to reduce shareholders’ uncertainty and increase trust, so that the stock prices reactions are less negative. Originality: This thesis provides a single framework connecting disasters, supply chain disruptions and firm performance, thereby bridging supply chain management and financial economics literature. The thesis evaluates the effect of hurricane-induced supply chain disruptions for the first time. It does not analyse just the effect of hurricane incident announcements but also hurricane announcements and compares both. Autoregressive integrated moving average (ARIMA) in combination with an intervention model was applied as an alternative to the frequently used event study methodology. This approach is chosen to evaluate the effect of hurricane announcements and hurricane incident announcements on the daily stock price time series of the firms in scope. Longer term effects can be evaluated, and the best fitting transfer functions are assessed. The model accounts for autocorrelation, trend, seasonality, and drift patterns. Additionally, the effect of the following potentially influencing factors was tested as these have only been touched on in the existing literature so far: impact type, impact extent, detailed damage, and preventive closure.Item Open Access Mobile robot automation in warehouses.(2022-12) Yildirim, Alp; Reefke, Hendrik; Aktas, EmelMobile robot systems are an automation solution in warehouses that make order fulfilment agile, flexible, and scalable to cope with customer orders' increasing volumes and complexities. Compared with manual operations, they combine higher productivity and throughput with lower operating costs. As the practical use of mobile robot systems increases, decision-makers are confronted with a plethora of decisions, but research is lagging in providing the needed academic insights and managerial guidance on the adoption and deployment of this novel technology. This PhD thesis aims to explain the mobile robot system implementation journey by conducting a mixed methods approach through three independent but interconnected papers. Paper 1 is based on a systematic literature review involving 107 papers from the literature. Paper 2 is a continuation of the systematic literature review to identify and evaluate available mobile robot systems in the market. It also offers mobile robot system selection approaches using the insights of five supply chain experts. Paper 3 is a multiple-case study involving four logistics functions from different countries. This thesis lists the potential motivations to adopt mobile robot systems. It offers multiple approaches to selecting an appropriate mobile robot system. It also provides a comprehensive adoption framework that elaborates on innovation diffusion theory and explains the entire mobile robot system adoption journey. Devising the phases of the mobile robot system adoption journey and categorising thirteen managerial decisions and nineteen contextual factors, this study offers guidance to supply chain managers and decision-makers.Item Open Access Product-service systems and supply chain circularity: a mixed methods investigation.(2021-05) Kuhl, Carl-Christian; Bourlakis, Michael; Aktas, Emel; Skipworth, HeatherThe circular economy (CE) aims to create economic and environmental benefits, by keeping products and materials at highest utility and value through long-lasting design, repair, reuse, refurbishment, and recycling. CE transformation results in a slowing, closing, and narrowing of resource loops, which is also termed supply chain circularity (SCC). Product-service systems (PSSs), in which manufacturers meet customer needs by providing services instead of selling products, are considered key business model innovations for increasing SCC. However, there is a lack of empirical evidence on whether PSSs actually contribute to SCC or whether they are a facade behind which linear ‘business-as-usual’ continues. This PhD thesis conducts a mixed methods investigation of the relationship between PSSs and SCC. It consists of three papers: 1) a systematic literature review (SLR) of 67 papers; 2) a quantitative survey of 206 machinery and equipment manufacturing firms in the United Kingdom (UK); 3) a multiple-case study of three manufacturing firms in Germany and the UK. The findings show that: 1) result-oriented PSSs have the highest potential contribution to SCC, followed by use- and finally product-oriented PSSs; 2) use-oriented PSSs are limited in contributing to a slowing of resource loops through refurbishment; 3) PSSs’ contribution to SCC depends on enabling and inhibiting contextual factors, especially organisational ones. In sum, this PhD study argues that PSSs can only catalyse the transition from a linear to a CE if an enabling business context is established. The PhD makes three key contributions to theory and practice: 1) it provides empirical evidence that PSSs do not inherently contribute to a slowing of resource loops; 2) it develops an empirically validated framework of enablers and barriers, particularly organisational ones; 3) it extends the SCC concept, by developing survey items and offering a first attempt at theorising how the transition to SCC occurs during a manufacturer’s servitization process.Item Open Access Supply chain activities and SME's financial performance: moderating effects of firm size and supply chain position.(Cranfield University, 2020-10) Wei, Denghao; Bourlakis, Michael; Aktas, EmelAlthough good supply chain management can drive large companies’ financial performance, its effectiveness in improving financial performance of small and medium-sized enterprises (SMEs) is still inconclusive, which results from the heterogeneity of SMEs compared to large companies. The objective of this thesis is to test the relationship between supply chain activities and SMEs’ financial performance and examine the moderating effects of firm size and supply chain position on this relationship. This thesis consists of three independent but interconnected papers, which fulfil the research objective collectively. Paper One titled “A conceptual framework of supply chain activities for SMEs’ financial performance” aims to identify supply chain activities that can drive the financial performance of SMEs based on a systematic literature review. Based on the 110 papers identified, a conceptual framework is established with nine supply chain activities that contribute to SMEs’ financial performance: purchasing, production, transport, inventory management, supplier partnership, customer partnership, supply chain strategy, quality management, and information sharing. Firm size and supply chain position are found to moderate the impact of supply chain activities on SMEs’ financial performance. To empirically test the conceptual framework, Paper Two titled “Supply chain activities and SMEs’ financial performance: The moderating effect of supply chain position” focuses on the performance of four internal supply chain activities (purchasing, production, transport, and inventory performance) and examines their relationships with SMEs’ financial performance along with the moderating effect of supply chain position. Based on survey data collected from 318 SMEs in the UK upstream food supply chain, partial least squares structural equation modelling results indicate that superior production and inventory performance can significantly improve the financial performance of SMEs, while purchasing and transport performance do not have significant effects. Multigroup analysis results suggest that supply chain position can moderate the impact of purchasing performance on profitability and liquidity and the impact of production and inventory performance on liquidity. Follow-up interviews were conducted with seven executives from UK food SMEs to triangulate the quantitative results obtained. Paper Three titled “Working capital management and SMEs’ financial performance: Moderating effects of firm size and supply chain position” empirically investigates the impact of working capital management and its three components (inventory holding days, accounts receivable days, and accounts payable days) on SMEs’ financial performance (profitability and liquidity) incorporating the moderating effects of firm size and supply chain position. Panel data regression results based on financial data of 325 SMEs in the UK upstream food supply chain from 2012 to 2018 suggest that cash conversion cycle, as a proxy of working capital management, is negatively associated with both profitability and liquidity of SMEs. All three working capital components have significantly negative relationships with SMEs’ profitability. Firm size and supply chain position significantly moderate some of those relationships. Those quantitative results were also triangulated by interviews with seven executives from UK food SMEs. This thesis empirically identifies that, the same as large companies, SMEs can also financially benefit from supply chain management. However, not all supply chain activities contribute to SMEs’ financial performance. The impact of supply chain activities on financial performance also varies with SMEs’ supply chain position and firm size. The results of this thesis can assist owner-managers of food SMEs with different sizes and supply chain positions to make informed decisions on the priority of supply chain activities in improving their companies’ financial performance.Item Open Access Sustainable customer solutions: an institutional theory approach to link resource integration and value creation.(Cranfield University, 2023-02) Widmer, Tobias; Bourlakis, Michael; Prior, Daniel; Aktas, EmelAlternatives to current resource intensive ways of production and consumption are required to achieve the UN Sustainable Development Goals. Transitioning from product sales to providing customer solutions (CS) has the potential to enhance sustainability. This transition, however, leads to managerial complexity, which increases further when trying to simultaneously become more sustainable. To succeed, manufacturers must ensure that their customers create economic, social, and environmental value with the CS. However, pursuing multiple goals may lead to tensions or require trade-offs. Informed by literature from Institutional Theory, industrial marketing, and sustainability, two studies were conducted. First, a multiple-case study investigated under which conditions resource integration (RI) is sustainable. By using ideal type logics, the study identified practices, values, and beliefs of business logics, as well as occurrences of conflicting, competing, and compatible logics which must be navigated collaboratively with customers to overcome barriers. Second, a single-case study investigated how RI translates into customers achieving their economic, social, and environmental goals. The study identified resources, value proposition components, and value-in-use constructs which were used in a means-end chain analysis, identifying multiple internal and external enablers and catalysts to stewardship practice in CS. The study found that CS can enhance sustainability compared to product sales, though it is not inherently guaranteed. The development of value propositions (VP) in CS is triggered internally or through the customers. Customers’ goals and the assessment thereof are continuously changing, requiring the VP to be dynamic and adapting by introducing and removing resources. A proposed framework of a value creation cycle establishes stewardship practice as a means to empirically explore and theoretically explain value creation in sustainable CS with institutional arrangements that manifest at multiple levels of a service-ecosystem. Along the value creation cycle, novel operational and cultural enablers and catalysts as well as challenges were identified, and are added to the body of knowledge which helps managers understand the requirements for successfully developing and implementing sustainable CS.