8 research outputs found

    An Improved Fuzzy Knowledge-Based Model For Long Stay Container Yards

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    This paper considers the problem of allocating newly arrived containers to stacks of existing containers in a yard when the departure date/time for containers is unknown. Many factors and constraints need to be considered when modelling this storage allocation problem. These constraints include the size, type and weight of the containers. The factors are the number of containers in a stack and the duration of stay of the topmost container in the stack. This paper aims to develop an improved Fuzzy Knowledge-Based ‘FKB’ model for best allocation practice of long-stay containers in a yard. In this model, the duration of stay factor does not need to be considered in the allocation decision if the duration of stay for the topmost containers in a stack is similar; hence, a new ‘ON/OFF’ strategy is proposed within the Fuzzy Knowledge-Based model to activate/deactivate this factor in the stacking algorithm whenever is required. Discrete Event Simulation and Fuzzy Knowledge-Based techniques are used to develop the proposed model. The model’s behaviour is tested using three real-life scenarios, including allocating containers in busy, moderately busy and quiet yards. The total number of re-handlings, the number of re-handlings per stack, and the number of re-handlings for containers were considered KPIs in each scenario

    Optimales Sortieren von Objekten

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    This thesis is concerned with the problem of optimally rearranging objects, in particular, railcars in a rail yard. The work is motivated by a research project of the Institute of Mathematical Optimization at Technische Universität Braunschweig, together with our project partner BASF, The Chemical Company, in Ludwigshafen. For many variants of such rearrangement problems - including the real-world application at BASF - we state the computational complexity by exploiting their equivalence to particular graph coloring, scheduling, and bin packing problems. We present mathematical optimization methods for determining schedules that are either optimal or close to optimal, and computational results are discussed from both a theoretical and practical point of view. In addition to the railway industry, there are other fields of application in which efficiently rearranging, sorting, or stacking is an important issue. For instance, the results obtained in this thesis could also be applied to solving certain piling problems in warehouses or container terminals.Die Dissertation beschäftigt sich mit dem optimalen Sortieren von Objekten, insbesondere von Güterwagen in Rangierbahnhöfen. Motiviert wurde diese Arbeit durch ein BMBF-gefördertes Projekt mit der BASF, The Chemical Company, in Ludwigshafen. Zahlreiche Varianten derartiger Sortierprobleme werden mathematisch formuliert und komplexitätstheoretisch eingeordnet. Für viele Varianten wird deren Äquivalenz zu bestimmten Graphenfärbungs-, Scheduling- sowie Bin-Packing-Problemen gezeigt. Für mehrere als theoretisch schwer bewiesene Fälle werden schnelle approximative Algorithmen vorgeschlagen, die Lösungen mit einer beweisbaren Güte liefern. Neben heuristischen Methoden werden auch exakte Verfahren zur Bestimmung optimaler Lösungen vorgestellt. Unter anderem handelt es sich bei den eingesetzten exakten Ansätzen um LP- sowie Lagrange-basierte Branch-and-Bound-Verfahren, die auf verschiedenen binären Modellen beruhen. Die Lösungsmethoden werden durch die Auswertung von Rechenergebnissen für reale Daten evaluiert. Den Abschluss der Dissertation bildet eine Kompetitivitätsanalyse diverser Online-Varianten, die dadurch gekennzeichnet sind, dass nicht alle relevanten Informationen zu Beginn der Planung vorliegen. Es sei auf das Verwertungspotenzial der in dieser Arbeit vorgestellten Optimierungsverfahren innerhalb anderer Anwendungsbereiche, in denen Sortieren, Stapeln, Lagern oder Verstauen eine Rolle spielen, hingewiesen

    List Cultures

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    We live in an age of lists, from magazine features to online clickbait. This book situates the list in a long tradition, asking key questions about the list as a cultural and communicative form. What, Liam Cole Young asks, can this seemingly innocuous form tell us about historical and contemporary media environments and logistical networks? Connecting German theories of cultural techniques to Anglo-American approaches that address similar issues, List Cultures makes a major contribution to debates about New Materialism and the post-human turn

    \u27What\u27s in a List?\u27 Cultural Techniques, Logistics, Poeisis

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    This research explores the list as a cultural and communicative form. Inspired by the ubiquity of rankings, bullet points and registries in contemporary ‘list culture,’ and by Jack Goody’s famous question ‘What’s in a list?’ (1977), I ask: how can this seemingly innocuous form be studied? What does its analysis tell us about historical and contemporary media environments and logistical networks? What can studying this unconventional object bring to media studies? I offer four intersecting arguments. The first proposes that media studies benefits from the incorporation of approaches and concepts that I group together as ‘media materialism.’ Approaches such as media archaeology, associated theories of cultural techniques, actor-network theory and logistical media studies give a more accurate account of media environments because they address more than the institutions, texts and audiences that are the traditional foci of North American media studies. The second argument presents the list as an example of what media materialism makes available. I position listing as a cultural technique that processes distinctions foundational to concepts and categories of social and imaginative life. The third argument proposes that lists cannot be easily dismissed or endorsed. Their complicated and often contradictory operations demand a precise tracing of how they function. The fourth argues that lists endure in our thoughts, texts, and programs because they negotiate tensions and paradoxes that have beguiled humans for centuries, e.g. between entropy and order or wonder and horror. These arguments are developed in four chapters. The first traces the list as a format that structures knowledge in popular music. The second maps listing as a cultural technique of administration in Nazi Germany. I show the Nazi census to be a limit case of a way of seeing and doing, what I term a ‘logistical worldview,’ that can be traced to fifteenth century double-entry bookkeeping. The third explores algorithmic lists of code and protocol in digital culture. These function not only administratively but also in ways that reveal a poetic capacity. The latter is the focus of the final chapter, which uses the words of Jorge Luis Borges and the images of Chris Marker to show the list as an imaginative form that clears a space for Heideggerian poeisis

    Using MapReduce Streaming for Distributed Life Simulation on the Cloud

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    Distributed software simulations are indispensable in the study of large-scale life models but often require the use of technically complex lower-level distributed computing frameworks, such as MPI. We propose to overcome the complexity challenge by applying the emerging MapReduce (MR) model to distributed life simulations and by running such simulations on the cloud. Technically, we design optimized MR streaming algorithms for discrete and continuous versions of Conway’s life according to a general MR streaming pattern. We chose life because it is simple enough as a testbed for MR’s applicability to a-life simulations and general enough to make our results applicable to various lattice-based a-life models. We implement and empirically evaluate our algorithms’ performance on Amazon’s Elastic MR cloud. Our experiments demonstrate that a single MR optimization technique called strip partitioning can reduce the execution time of continuous life simulations by 64%. To the best of our knowledge, we are the first to propose and evaluate MR streaming algorithms for lattice-based simulations. Our algorithms can serve as prototypes in the development of novel MR simulation algorithms for large-scale lattice-based a-life models.https://digitalcommons.chapman.edu/scs_books/1014/thumbnail.jp

    Safety and Reliability - Safe Societies in a Changing World

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    The contributions cover a wide range of methodologies and application areas for safety and reliability that contribute to safe societies in a changing world. These methodologies and applications include: - foundations of risk and reliability assessment and management - mathematical methods in reliability and safety - risk assessment - risk management - system reliability - uncertainty analysis - digitalization and big data - prognostics and system health management - occupational safety - accident and incident modeling - maintenance modeling and applications - simulation for safety and reliability analysis - dynamic risk and barrier management - organizational factors and safety culture - human factors and human reliability - resilience engineering - structural reliability - natural hazards - security - economic analysis in risk managemen

    Leading Towards Voice and Innovation: The Role of Psychological Contract

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    Background: Empirical evidence generally suggests that psychological contract breach (PCB) leads to negative outcomes. However, some literature argues that, occasionally, PCB leads to positive outcomes. Aim: To empirically determine when these positive outcomes occur, focusing on the role of psychological contract (PC) and leadership style (LS), and outcomes such as employ voice (EV) and innovative work behaviour (IWB). Method: A cross-sectional survey design was adopted, using reputable questionnaires on PC, PCB, EV, IWB, and leadership styles. Correlation analyses were used to test direct links within the model, while regression analyses were used to test for the moderation effects. Results: Data with acceptable psychometric properties were collected from 11 organisations (N=620). The results revealed that PCB does not lead to substantial changes in IWB. PCB correlated positively with prohibitive EV, but did not influence promotive EV, which was a significant driver of IWB. Leadership styles were weak predictors of EV and IWB, and LS only partially moderated the PCB-EV relationship. Conclusion: PCB did not lead to positive outcomes. Neither did LS influencing the relationships between PCB and EV or IWB. Further, LS only partially influenced the relationships between variables, and not in a manner which positively influence IWB

    Assuming Data Integrity and Empirical Evidence to The Contrary

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    Background: Not all respondents to surveys apply their minds or understand the posed questions, and as such provide answers which lack coherence, and this threatens the integrity of the research. Casual inspection and limited research of the 10-item Big Five Inventory (BFI-10), included in the dataset of the World Values Survey (WVS), suggested that random responses may be common. Objective: To specify the percentage of cases in the BRI-10 which include incoherent or contradictory responses and to test the extent to which the removal of these cases will improve the quality of the dataset. Method: The WVS data on the BFI-10, measuring the Big Five Personality (B5P), in South Africa (N=3 531), was used. Incoherent or contradictory responses were removed. Then the cases from the cleaned-up dataset were analysed for their theoretical validity. Results: Only 1 612 (45.7%) cases were identified as not including incoherent or contradictory responses. The cleaned-up data did not mirror the B5P- structure, as was envisaged. The test for common method bias was negative. Conclusion: In most cases the responses were incoherent. Cleaning up the data did not improve the psychometric properties of the BFI-10. This raises concerns about the quality of the WVS data, the BFI-10, and the universality of B5P-theory. Given these results, it would be unwise to use the BFI-10 in South Africa. Researchers are alerted to do a proper assessment of the psychometric properties of instruments before they use it, particularly in a cross-cultural setting
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