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Balancing energy and performance: efficient allocation of solver jobs on high-performance computing systems
No full textMany combinatorial optimization methods and related optimization software, particularly those for mixed-integer programming, exhibit limited scalability when utilizing parallel computing resources, whether across multiple cores or multiple nodes. Nevertheless, high-performance computing (HPC) systems continue to grow in size, with increasing core counts, memory capacity, and power consumption. Rather than dedicating all available resources to a single problem instance, HPC systems can be leveraged to solve multiple optimization instances concurrently – a common requirement in applications such as stochastic optimization, policy design for sequential decision making, parameter tuning, and optimization-as-a-service. In this work, we study strategies for efficiently allocating solver jobs across compute nodes, exploring how to schedule multiple optimization jobs across a given number of cores or nodes. Using metrics from performance monitoring and benchmarking tools as well as metered PDUs, we analyze trade-offs between energy consumption and runtime, providing insights into how to balance computational efficiency and sustainability in large-scale optimization workflows.Vo
Introducing organizational (dis)entanglements
No full textThis is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs licence (https://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work is properly cited.Scholars and pundits focusing on the changing international order and its possible fragmentation often pay little attention to the manifold relationships between international organizations (IOs). Neglecting inter-organizational relationships, we argue, biases discussions towards doomsday predictions and reinforces the perception of global fragmentation. In this Forum, we address these biases by bringing together two strands of IR scholarship: power rivalry/transition and regime complexity. We do so by introducing the concept of organizational (dis)entanglements. An examination of how more and less powerful national and international policymakers engage and disengage IOs, highlights processes of reinforcing, muddling through, or undermining various ongoing order-making initiatives. The individual contributions examine organizational (dis)entanglements by highlighting actors’ various multilateral order-making attempts across IOs, global and regional ordering dynamics through IOs, and the roles international bureaucrats play in these processes. These contributions help identify new directions of inquiry in the study of IOs and international order by, for example, demonstrating that actors can engage with competition and cooperation simultaneously. Not all ordering attempts are equally likely to radically change global politics.Les chercheurs et experts qui se concentrent sur l’évolution de l'ordre international et sa fragmentation potentielle accordent souvent peu d'attention aux relations multiples entre les organisations internationales (OI). Selon nous, l'omission des relations interorganisationnelles oriente les discussions vers des prédictions catastrophiques et renforce la perception d'une fragmentation mondiale. Dans ce forum, nous traitons de ces biais en rapprochant deux branches de la recherche en RI : rivalité/transition de pouvoir et complexité de régimes. Pour ce faire, nous présentons le concept de (dés)enchevêtrement organisationnel. En examinant comment des législateurs nationaux et internationaux plus ou moins puissants mettent en place et interrompent des collaborations entre OI, nous mettons en lumière les processus de renforcement, de débrouille ou de remise en question concernant les initiatives en cours qui visent à instaurer un ordre. Chaque contribution analyse les (dés)enchevêtrements organisationnels en mettant en lumière les tentatives de création d'ordres multilatéraux de puissants acteurs chez les différentes OI, la relation dynamique entre la création d'ordre mondial et régional par le biais des OI et le rôle que les bureaucrates internationaux jouent dans ces processus. Ces contributions permettent d'identifier de nouvelles orientations de recherche dans l’étude des OI et de l'ordre international en démontrant par exemple que les acteurs peuvent simultanément avoir recours à la concurrence et la coopération. Toutes les tentatives d'instauration d'ordre n'ont pas les mêmes chances de modifier radicalement la politique mondiale.Los académicos y expertos que centran su trabajo en el cambiante orden internacional y en su posible fragmentación tienden, a menudo, a prestar poca atención a las múltiples relaciones existentes entre las organizaciones internacionales (OOII). Argumentamos que el hecho de descuidar las relaciones interorganizacionales sesga los debates con respecto a predicciones apocalípticas y refuerza la percepción de fragmentación global. En este Foro, abordamos estos sesgos reuniendo dos vertientes de la investigación en el campo de las RRII: la rivalidad/transición de poder y la complejidad del régimen. Llevamos esto a cabo mediante la presentación del concepto de (des)enredos organizacionales. Realizamos un estudio en materia de cómo los responsables de la formulación de políticas, nacionales e internacionales, más y menos poderosos, se relacionan y desvinculan de las OOII. Este estudio pone de relieve los procesos de refuerzo, obstaculización o debilitamiento de las iniciativas de generación de órdenes en curso. Las contribuciones individuales examinan el (des)enredo organizacional y destacan los intentos de creación de órdenes multilaterales por parte de los actores poderosos a través de las OOII, la relación dinámica entre el ordenamiento global y regional a través de las OOII y el papel que juegan los burócratas internacionales en estos procesos. Estas contribuciones ayudan a identificar nuevas direcciones de investigación en el estudio de las OOII y el orden internacional ya que, por ejemplo, demuestran que los actores pueden comprometerse con la competencia y la cooperación simultáneamente. No todos los intentos de ordenamiento tienen las mismas probabilidades de cambiar radicalmente la política mundial.Vo
Numerische Analyse der nichtlinearen Wellenausbreitung in delaminierten Faser-Metall-Laminaten
No full textDer Fokus der vorliegenden Arbeit liegt auf der numerischen Untersuchung der nichtlinearen Wellenausbreitung aufgrund interlaminarer Schäden wie Delaminationen in Faser−Metall−Laminaten im Hinblick auf ihre Anwendung in der strukturellen Schadensdetektion und −charakterisierung. Faser−Metall−Laminate bezeichnet eine Gruppe von Hybridwerkstoffen, deren Struktur aus alternierenden Schichten von Metall und faserverstärkten Kunststoffen besteht. Im Rahmen der Untersuchung wird ein numerisches Modell zugrunde gelegt, wobei die Modellierung einer physikalisch validen und realitätsnahen Delamination sowie ihrer Interaktion mit geführten Wellen einen besonderen Augenmerk einnehmen. Die komplexen mechanischen Eigenschaften von Faser−Metall−Laminaten erfordern eine eingehende Analyse ihres globalen nichtlinearen Verhaltens. Hierzu werden hyperelastische Materialmodelle eingesetzt, welche die Analyse höherharmonischer Moden und des Nichtlinearitätsparameters über weite Ausbreitungsstrecken ermöglichen. Die Analyse ergibt ein konsistentes Ergebnis im Zusammenhang mit der analytisch berechneten Dispersionslänge in Bezug auf den kumulativen bzw. quasi−kumulativen Effekt. Darauf aufbauend erfolgt die Analyse der nichtlinearen Akustik mittels Kontaktdefinition an den Delaminationsgrenzen hinsichtlich der Generierung höherharmonischer Moden sowie des Einflusses auf die Verschiebungsfelder. Die vorliegende Analyse demonstriert, dass das kumulative Verhalten der höherharmonischen Moden in der unmittelbaren Nähe der Delamination eine starke Ausprägung zeigt und nach außen hin abklingt. Das nichtlineare Ausbreitungsverhalten unterscheidet sich also aufgrund der auftretenden höher− und subharmonischen Moden im Frequenzbereich mit den entsprechenden Peaks maßgeblich vom linearen Fall. Somit erweist sich die Verwendung von geführten Wellen zur Detektion von Delaminationen in Faser−Metall−Laminate als eine geeignete Methode.This study focuses on the numerical investigation of nonlinear wave propagation due to interlaminar damage such as delamination in fibre−metal−laminates with regard to their application in structural damage detection and characterisation. Fibre refers to a group of hybrid materials consisting of alternating layers of metal and fibre reinforced polymers. The investigation is based on a numerical model, with particular attention given to the modelling of physically valid and realistic delamination and its interaction with guided waves. The complex mechanical properties of fibre metal laminate require a thorough analysis of its global nonlinear behaviour. For this purpose, hyperelastic material models are used, which enable the analysis of higher harmonic modes and the nonlinearity parameter over long propagation distances. This analysis yields consistent results in correlation with the analytically determined dispersion length with regard to the cumulative or quasi-cumulative effect. Based on this, the nonlinear acoustics are analysed by defining contact at the delamination boundaries with regard to the generation of high harmonic modes and the influence on the displacement fields. The present analysis demonstrates that the cumulative behaviour of the higher harmonic modes is strongly pronounced in the immediate proximity of the delamination and attenuates towards the periphery. The nonlinear propagation behaviour therefore differs significantly from the linear case due to the higher- and subharmonic modes occurring in the frequency range with the corresponding peaks. Thus, the use of guided waves for the detection of delamination in fibre metal laminates proves to be a suitable method.Vo
MicroLabVR: interactive 3D visualization of simulated spatiotemporal microbiome data in virtual reality
No full textThis work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License (http://creativecommons.org/licenses/by-nc-sa/4.0/).Microbiomes are a vital part of the human body, engaging in tasks like food digestion and immune defense. Their structure and function must be understood in order to promote host health and facilitate swift recovery during disease. Due to the difficulties in experimentally studying these systems in situ, more research is being conducted in the field of mathematical modeling. Visualizing spatiotemporal data is challenging, and current tools that simulate microbial communities' spatial and temporal development often only provide limited functionalities, often requiring expert knowledge to generate useful results. To overcome these limitations, we provide a user-friendly tool to interactively explore spatiotemporal simulation data, called MicroLabVR, which transfers spatial data into virtual reality (VR) while following guidelines to enhance user experience (UX). With MicroLabVR, users can import CSV datasets containing population growth, substance concentration development, and metabolic flux distribution data. The implemented visualization methods allow users to evaluate the dataset in a VR environment interactively. MicroLabVR aims to improve data analysis for the user by allowing the exploration of microbiome data in their spatial context.Vo
Military vehicle shifting in Roll-on/Roll-off terminals
No full textRoll-on/Roll-off (RoRo) vessels allow the oversea transportation of vehicles that can be driven onto a ship on their own or by means of a platform vehicle. In civilian RoRo operations, vehicles are typically loaded in relatively large batches according to their destination terminals. In this article, however, we focus on a military setting, where the loading of vehicles strictly follows vehicle characteristics and involves multiple decision makers that influence the overall process. The vehicles arrive at the terminal in given sequences and need to be shifted to a parking area such that they can later be loaded onto the ship according to a given stowage plan that is related to the vehicle characteristics. We formulate the underlying operational planning problem of shifting military vehicles in a RoRo terminal and provide theoretical insights regarding its computational complexity, associated meta problems and the structure of feasible solutions. We then leverage these insights in a mathematical model and heuristic approaches that are designed to be easily implementable in practice. We evaluate the heuristics in a comprehensive computational study and derive implications and recommendations for their application in practice.A
[Rezension zu] Hermann Diebel-Fischer, Nicole Kunkel, Julian Zeyher-Quattlender (Hg.): Mensch und Maschine im Zeitalter »Künstlicher Intelligenz«. Theologisch-ethische Herausforderungen (LLG 45), Berlin: Lit-Verlag 2023, 164 S.
No full textVo
Schooling the (artificially) intelligent writer
No full textThis article is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ .Schools are increasingly grappling with challenges posed by generative artificial intelligence (GenAI) technologies, exemplified by the omnipresence of chatbots and their repercussions for pedagogical practices. This paper explores the case of how ChatGPT unfolds in, and affects, students’ writing practices and what the implications are thereof. We conceptualise ChatGPT as a "thinking infrastructure" that structures and affects attention, decision-making, and cognition. By researching two schools in Belgium and Germany, we discuss how students engage with ChatGPT when performing school tasks. Our analysis shows how ChatGPT affects students’ writing practices by generating habits, valuating knowledge, cultivating affinity, and prompting thought. This, we argue, illuminates shifts in what it means to be educated today. We suggest the need to further articulate the new conditions of learning emerging through GenAI technologies and propose the need for a pedagogy that fosters infrastructure literacy.Vo