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Eleftherios Iakovou - One of the best experts on this subject based on the ideXlab platform.

  • Sustainable supply chain management in the digitalisation era: The impact of Automated Guided Vehicles
    Journal of Cleaner Production, 2017
    Co-Authors: Dimitrios Bechtsis, Naoum Tsolakis, Dimitrios Vlachos, Eleftherios Iakovou
    Abstract:

    Internationalization of markets and climate change introduce multifaceted challenges for modern supply chain (SC) management in the today's digitalisation era. On the other hand, Automated Guided Vehicle (AGV) systems have reached an age of maturity that allows for their utilization towards tackling dynamic market conditions and aligning SC management focus with sustainability considerations. However, extant research only myopically tackles the sustainability potential of AGVs, focusing more on addressing network optimization problems and less on developing integrated and systematic methodological approaches for promoting economic, environmental and social sustainability. To that end, the present study provides a critical taxonomy of key decisions for facilitating the adoption of AGV systems into SC design and planning, as these are mapped on the relevant strategic, tactical and operational levels of the Natural Hierarchy. We then propose the Sustainable Supply Chain Cube (S2C2), a conceptual tool that integrates sustainable SC management with the proposed hierarchical decision-making framework for AGVs. Market opportunities and the potential of integrating AGVs into a SC context with the use of the S2C2 tool are further discussed.

  • waste biomass to energy supply chain management a critical synthesis
    Waste Management, 2010
    Co-Authors: Eleftherios Iakovou, Dimitrios Vlachos, A Karagiannidis, A Toka, A Malamakis
    Abstract:

    The development of renewable energy sources has clearly emerged as a promising policy towards enhancing the fragile global energy system with its limited fossil fuel resources, as well as for reducing the related environmental problems. In this context, waste biomass utilization has emerged as a viable alternative for energy production, encompassing a wide range of potential thermochemical, physicochemical and bio-chemical processes. Two significant bottlenecks that hinder the increased biomass utilization for energy production are the cost and complexity of its logistics operations. In this manuscript, we present a critical synthesis of the relative state-of-the-art literature as this applies to all stakeholders involved in the design and management of waste biomass supply chains (WBSCs). We begin by presenting the generic system components and then the unique characteristics of WBSCs that differentiate them from traditional supply chains. We proceed by discussing state-of-the-art energy conversion technologies along with the resulting classification of all relevant literature. We then recognize the Natural Hierarchy of the decision-making process for the design and planning of WBSCs and provide a taxonomy of all research efforts as these are mapped on the relevant strategic, tactical and operational levels of the Hierarchy. Our critical synthesis demonstrates that biomass-to-energy production is a rapidly evolving research field focusing mainly on biomass-to-energy production technologies. However, very few studies address the critical supply chain management issues, and the ones that do that, focus mainly on (i) the assessment of the potential biomass and (ii) the allocation of biomass collection sites and energy production facilities. Our analysis further allows for the identification of gaps and overlaps in the existing literature, as well as of critical future research areas.

María Luisa Femenías - One of the best experts on this subject based on the ideXlab platform.

Dimitrios Vlachos - One of the best experts on this subject based on the ideXlab platform.

  • Sustainable supply chain management in the digitalisation era: The impact of Automated Guided Vehicles
    Journal of Cleaner Production, 2017
    Co-Authors: Dimitrios Bechtsis, Naoum Tsolakis, Dimitrios Vlachos, Eleftherios Iakovou
    Abstract:

    Internationalization of markets and climate change introduce multifaceted challenges for modern supply chain (SC) management in the today's digitalisation era. On the other hand, Automated Guided Vehicle (AGV) systems have reached an age of maturity that allows for their utilization towards tackling dynamic market conditions and aligning SC management focus with sustainability considerations. However, extant research only myopically tackles the sustainability potential of AGVs, focusing more on addressing network optimization problems and less on developing integrated and systematic methodological approaches for promoting economic, environmental and social sustainability. To that end, the present study provides a critical taxonomy of key decisions for facilitating the adoption of AGV systems into SC design and planning, as these are mapped on the relevant strategic, tactical and operational levels of the Natural Hierarchy. We then propose the Sustainable Supply Chain Cube (S2C2), a conceptual tool that integrates sustainable SC management with the proposed hierarchical decision-making framework for AGVs. Market opportunities and the potential of integrating AGVs into a SC context with the use of the S2C2 tool are further discussed.

  • waste biomass to energy supply chain management a critical synthesis
    Waste Management, 2010
    Co-Authors: Eleftherios Iakovou, Dimitrios Vlachos, A Karagiannidis, A Toka, A Malamakis
    Abstract:

    The development of renewable energy sources has clearly emerged as a promising policy towards enhancing the fragile global energy system with its limited fossil fuel resources, as well as for reducing the related environmental problems. In this context, waste biomass utilization has emerged as a viable alternative for energy production, encompassing a wide range of potential thermochemical, physicochemical and bio-chemical processes. Two significant bottlenecks that hinder the increased biomass utilization for energy production are the cost and complexity of its logistics operations. In this manuscript, we present a critical synthesis of the relative state-of-the-art literature as this applies to all stakeholders involved in the design and management of waste biomass supply chains (WBSCs). We begin by presenting the generic system components and then the unique characteristics of WBSCs that differentiate them from traditional supply chains. We proceed by discussing state-of-the-art energy conversion technologies along with the resulting classification of all relevant literature. We then recognize the Natural Hierarchy of the decision-making process for the design and planning of WBSCs and provide a taxonomy of all research efforts as these are mapped on the relevant strategic, tactical and operational levels of the Hierarchy. Our critical synthesis demonstrates that biomass-to-energy production is a rapidly evolving research field focusing mainly on biomass-to-energy production technologies. However, very few studies address the critical supply chain management issues, and the ones that do that, focus mainly on (i) the assessment of the potential biomass and (ii) the allocation of biomass collection sites and energy production facilities. Our analysis further allows for the identification of gaps and overlaps in the existing literature, as well as of critical future research areas.

Cormode Graham - One of the best experts on this subject based on the ideXlab platform.

  • Towards a Theory of Parameterized Streaming Algorithms
    2019
    Co-Authors: Chitnis Rajesh, Cormode Graham
    Abstract:

    Parameterized complexity attempts to give a more fine-grained analysis of the complexity of problems: instead of measuring the running time as a function of only the input size, we analyze the running time with respect to additional parameters. This approach has proven to be highly successful in delineating our understanding of \NP-hard problems. Given this success with the TIME resource, it seems but Natural to use this approach for dealing with the SPACE resource. First attempts in this direction have considered a few individual problems, with some success: Fafianie and Kratsch [MFCS'14] and Chitnis et al. [SODA'15] introduced the notions of streaming kernels and parameterized streaming algorithms respectively. For example, the latter shows how to refine the $\Omega(n^2)$ bit lower bound for finding a minimum Vertex Cover (VC) in the streaming setting by designing an algorithm for the parameterized $k$-VC problem which uses $O(k^{2}\log n)$ bits. In this paper, we initiate a systematic study of graph problems from the paradigm of parameterized streaming algorithms. We first define a Natural Hierarchy of space complexity classes of FPS, SubPS, SemiPS, SupPS and BrutePS, and then obtain tight classifications for several well-studied graph problems such as Longest Path, Feedback Vertex Set, Dominating Set, Girth, Treewidth, etc. into this Hierarchy. (see paper for full abstract)Comment: Extended abstract in IPEC 2019. arXiv admin note: text overlap with arXiv:1603.05715 by other author

  • Towards a Theory of Parameterized Streaming Algorithms
    LIPIcs - Leibniz International Proceedings in Informatics. 14th International Symposium on Parameterized and Exact Computation (IPEC 2019), 2019
    Co-Authors: Chitnis Rajesh, Cormode Graham
    Abstract:

    Parameterized complexity attempts to give a more fine-grained analysis of the complexity of problems: instead of measuring the running time as a function of only the input size, we analyze the running time with respect to additional parameters. This approach has proven to be highly successful in delineating our understanding of NP-hard problems. Given this success with the TIME resource, it seems but Natural to use this approach for dealing with the SPACE resource. First attempts in this direction have considered a few individual problems, with some success: Fafianie and Kratsch [MFCS\u2714] and Chitnis et al. [SODA\u2715] introduced the notions of streaming kernels and parameterized streaming algorithms respectively. For example, the latter shows how to refine the Omega(n^2) bit lower bound for finding a minimum Vertex Cover (VC) in the streaming setting by designing an algorithm for the parameterized k-VC problem which uses O(k^{2}log n) bits. In this paper, we initiate a systematic study of graph problems from the paradigm of parameterized streaming algorithms. We first define a Natural Hierarchy of space complexity classes of FPS, SubPS, SemiPS, SupPS and BrutePS, and then obtain tight classifications for several well-studied graph problems such as Longest Path, Feedback Vertex Set, Dominating Set, Girth, Treewidth, etc. into this Hierarchy (see Figure 1 and Table 1). On the algorithmic side, our parameterized streaming algorithms use techniques from the FPT world such as bidimensionality, iterative compression and bounded-depth search trees. On the hardness side, we obtain lower bounds for the parameterized streaming complexity of various problems via novel reductions from problems in communication complexity. We also show a general (unconditional) lower bound for space complexity of parameterized streaming algorithms for a large class of problems inspired by the recently developed frameworks for showing (conditional) kernelization lower bounds. Parameterized algorithms and streaming algorithms are approaches to cope with TIME and SPACE intractability respectively. It is our hope that this work on parameterized streaming algorithms leads to two-way flow of ideas between these two previously separated areas of theoretical computer science

A Malamakis - One of the best experts on this subject based on the ideXlab platform.

  • waste biomass to energy supply chain management a critical synthesis
    Waste Management, 2010
    Co-Authors: Eleftherios Iakovou, Dimitrios Vlachos, A Karagiannidis, A Toka, A Malamakis
    Abstract:

    The development of renewable energy sources has clearly emerged as a promising policy towards enhancing the fragile global energy system with its limited fossil fuel resources, as well as for reducing the related environmental problems. In this context, waste biomass utilization has emerged as a viable alternative for energy production, encompassing a wide range of potential thermochemical, physicochemical and bio-chemical processes. Two significant bottlenecks that hinder the increased biomass utilization for energy production are the cost and complexity of its logistics operations. In this manuscript, we present a critical synthesis of the relative state-of-the-art literature as this applies to all stakeholders involved in the design and management of waste biomass supply chains (WBSCs). We begin by presenting the generic system components and then the unique characteristics of WBSCs that differentiate them from traditional supply chains. We proceed by discussing state-of-the-art energy conversion technologies along with the resulting classification of all relevant literature. We then recognize the Natural Hierarchy of the decision-making process for the design and planning of WBSCs and provide a taxonomy of all research efforts as these are mapped on the relevant strategic, tactical and operational levels of the Hierarchy. Our critical synthesis demonstrates that biomass-to-energy production is a rapidly evolving research field focusing mainly on biomass-to-energy production technologies. However, very few studies address the critical supply chain management issues, and the ones that do that, focus mainly on (i) the assessment of the potential biomass and (ii) the allocation of biomass collection sites and energy production facilities. Our analysis further allows for the identification of gaps and overlaps in the existing literature, as well as of critical future research areas.