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Machine Learning For Determining Planned Order Lead Times In Job Shop Production: A Systematic Review Of Input Factors And Applied Methods
Full text linkThe accurate planning of order lead times enables companies to confirm feasible delivery times to their customers and facilitates more efficient planning of production capacities and procurement processes. In practice, the commonly used methods for determining planned order lead times are constrained by simplified assumptions and the limited consideration of input factors. As a result, they struggle to adapt to changing conditions, such as varying production workloads or short-term employee shortages. For manufacturers engaged in make-to-order production with complex structures, such as job shop production, consequently delayed operations result in an insufficient delivery performance. Conversely, early operations lead to the accumulation of unnecessary inventories. In this context, machine learning methods are expected to offer significant potential for dealing with changing circumstances due to their ability to utilize a wide range of input factors. A variety of machine learning approaches incorporating diverse data sets have been proposed in the literature. This paper presents the findings of a systematic literature review on the potential input factors for determining planned order lead times in job shop production. Moreover, the utilized machine learning methods to quantify these input factors are identified. For this purpose, the input data used in case studies, the machine learning methods applied for both feature selection and regression analysis, as well as the evaluation metrics and explainable artificial intelligence approaches, are analyzed and synthesized. This allows the identification of research gaps regarding input factors and their quantification for determining planned order lead times
Environmental Sustainability Assessment Of Factories With BIM: Relevance And Challenges For A Holistic Approach
Full text linkEnvironmental sustainability is increasingly seen as a central objective of a factory in order to ensure the long-term competitiveness of industrial companies. In addition to growing social and regulatory pressures, the urgency is further emphasized by the increasing sustainability awareness of companies. This not only enhances their attractiveness to customers and investors but can also help to reduce costs.
The assessment of the environmental sustainability of factories can be used in a variety of ways and in different planning and life cycle phases. For example, the ecological assessment can be used both in factory planning to select a preferred planning variant and in factory operation to record the current status. Conventional, often manual planning methods frequently prove to be insufficient to fulfil requirements such as the consideration of the entire life cycle of a factory or the demand for high data transparency. The use of Building Information Modeling (BIM) is a promising way of overcoming this challenge, as it is already used in practice to capture relevant information and data for the life cycle of a building.
This article demonstrates the importance and challenge of assessing the ecological sustainability of factories from a spatial and process perspective using BIM. Based on this, requirements are formulated for a standardized and application-oriented procedure that enables a life cycle-oriented sustainability assessment of factories
Privacy-Aware Supply Chain Ratings: Interdisciplinary Research On Collaborative Supply Chain Management
Full text linkThe establishment, expansion, and operation of reliable value-creation networks present an increasing challenge for manufacturing companies, given the growing volatility of the market environment in which they operate. For example, the development of new business areas, mass customization, or the disruption of supply chains frequently necessitates the establishment of partnerships with new suppliers, both short- and long-term. The utilization of supplier key performance indicators (KPIs) can facilitate the selection of new business partners, as they provide a quick and objective indication of their reliability. Nevertheless, access to potentially sensitive KPIs, such as a supplier's on-time delivery performance, is currently mainly limited to existing supplier relationships and not made available to other companies. This paper presents a coordinated approach for supplier rating systems, thereby enabling the privacy-aware exchange of supplier KPIs across organizations and exemplifies it using an application in the 'Internet of Production'. Specifically, we conduct interdisciplinary research by formulating the requirements from a business perspective (supply chain design, trust in data sharing, and business models) and evaluating promising solutions from a technical perspective (information security, data quality, data sovereignty, and collaboration). This approach enables the combination of state-of-the-art technology with the evolving requirements of stakeholders, thus creating new paths for exploiting inter-organizational supply chain rating
Key Success Factors and Challenges in Integrating Blockchain Technology in Global Supply Chains
Full text linkGlobal supply chains are complex and need to meet increasing demands, requiring more transparency and traceability. Blockchain technology (BCT) is a potential solution to address these demands due to its inherent immutability, decentralization and transparency. However, BCT integration in global supply chain management (SCM) is not always successful, resulting in sunk costs and wasted resources. This paper identifies the key success factors and challenges of blockchain integration in global supply chains. The research in this paper extracts primary data from ten semi-structured industry expert interviews and secondary data from literature. Based on the findings, key success factors encompass adequate education on BCT with the right level of abstraction for each supply chain participant, and the willingness to agree on standards, considering geographical variations and infrastructural development. Conversely, key challenges involve deciding which data to put on the blockchain, stakeholder collaboration and interoperability with existing systems. This paper concludes with recommendations for successfully implementing BCT projects
Toward the synthesis of Lycorine-type amaryllidaceae alkaloids supported by continuous-flow chemistry
No full textLycorine-type alkaloids belong to the Amaryllidaceae alkaloid family, which have been studied for their pharmacological and biological properties in the past decades. Their characteristic framework consists of a tetracyclic pyrrolo[d,e]phenanthridine (galanthan) core, with the majority of these alkaloids exhibiting a trans-junction between the B and C ring. However, only a few, like γ-lycorane, fortucine, siculinine and kirkine have a cis-junction between B/C. This research aims to develop a divergent synthetic access to several targets in this natural product class. In the retrosynthetic strategy, it was envisioned to access the cis-fused class of natural products by implementing a synthetic sequence consisting of a [2+2]-photocycloaddition, a Ramberg─Bäcklund ring contraction followed by a formal electrocyclic ring opening and a Kornblum─DeLaMare oxidation, which has already been successfully employed in the total synthesis of aspidodispermine from our group, or a short-cut via a Diels─Alder reaction/ring-opening/oxidation sequence. The resulting intermediate serves as a platform for accessing several natural products of the lycorine-type alkaloid family. Remarkably, by epimerization of C15, also the trans-fused lycorine-type alkaloids become available by this divergent synthetic approach, emphasizing the versatility of this strategy. In the first part of this thesis, several strategies for accessing a precursor were explored. Nucleophilic substitution strategies were unsuccessful, as well as a transition metal-catalyzed cyclization approach. Ultimately, the desired N-furfurylethyl-isoquinolone was assembled via an amide coupling/cyclization sequence between a benzoic acid and a furfuryl-substituted amine. The obtained imide was further reduced, and elimination afforded the isoquinolone derivative. The second part focused on Diels─Alder reactions with furan, which proved challenging. Consequently, in the third part, a strain-release strategy was investigated. A singlet oxygen-mediated furan opening yielded a hydroxybutenolide. Initial [2+2]-photocycloaddition was successful, but reduction attempts repeatedly reverted to the retro-[2+2]-reaction product. By reversing the order of reduction and [2+2]-reaction, the desired butanolide derivative was obtained and transformed to its thioester. In a low-scale, UPLC-traced sequence, this thioester was shown to be feasible for conversion to a bicyclo[2.2.0]hexene motif via a Ramberg─Bäcklund reaction. Future work will focus on verifying this sequence and completing the synthesis to the advanced intermediate through (formal) electrocyclic ring opening and Kornblum─DeLaMare reaction.Lycorine-type Alkaloide gehören zur Familie der Amaryllidaceae-Alkaloide, die aufgrund ihrer pharmakologischen und biologischen Eigenschaften untersucht wurden. Ihr charakteristisches Gerüst besteht aus einem tetracyclischen Pyrrolo[d,e]phenanthridin (Galanthan)-Kern, wobei die Mehrheit dieser Alkaloide eine trans-Verknüpfung zwischen dem B- und C-Ring aufweist. Nur wenige Vertreter, wie γ-Lycorane, Fortucine, Siculinine und Kirkine, besitzen eine cis-Verknüpfung zwischen B/C. Ziel dieser Forschung ist es, einen divergenten synthetischen Zugang zu mehreren Zielmolekülen dieser Naturstoffklasse zu entwickeln. In der retrosynthetischen Strategie wurde geplant, die cis-verknüpfte Klasse von Naturstoffen über eine Sequenz aus einer [2+2]-Photocycloaddition, einer Ramberg─Bäcklund Reaktion, gefolgt von einer formell elektrocyclischen Ringöffnung und einer Kornblum─DeLaMare Oxidation zu synthetisieren. Desweiteren wird eine Abkürzung über eine Diels─Alder-Reaktion/Ringöffnung/Oxidationssequenz anvisiert. Das resultierende Intermediat dient als Plattform für den Zugang zu mehreren Naturstoffen der Lycorine-Alkaloid Familie. Durch Epimerisierung von C15 sind auch die trans-verknüpften Lycorine-Alkaloide durch diesen divergenten synthetischen Ansatz zugänglich, was die Vielseitigkeit dieser Strategie betont. Im ersten Teil dieser Arbeit wurden verschiedene Strategien zur Synthese eines geeigneten Vorläufers untersucht. Nukleophile Substitutionsstrategien, sowie ein Übergangsmetall-katalysierter Cyclisierungsansatz waren erfolglos. Letztendlich wurde das gewünschte N-Furfurylethyl-Isochinolon durch eine Amidkupplung/Cyclisierungssequenz zwischen einer Benzoesäure und einem furfuryl-substituierten Amin erreicht. Das erhaltene Imid wurde reduziert, und die Eliminierung ergab das gewünschte Isochinolonderivat. Der zweite Teil konzentrierte sich auf Diels─Alder-Reaktionen mit Furan, die sich als herausfordernd erwiesen. Im dritten Teil wurde eine Spannungsfreisetzungsstrategie untersucht. Eine durch Singulett-Sauerstoff vermittelte Furanöffnung ergab ein Hydroxybutenolid. Die [2+2]-Photocycloaddition war erfolgreich, aber Reduktionsversuche führten wiederholt zum retro-[2+2]-Reaktionsprodukt. Durch Umkehrung der Reihenfolge von Reduktion und [2+2]-Reaktion wurde das gewünschte Butanolid-Derivat erhalten, welches weiter in einen Thioester umgewandelt wurde. In einer UPLC-verfolgten Sequenz wurde gezeigt, dass dieser Thioester für die Umwandlung in ein Bicyclo[2.2.0]hexen-Motiv über eine Ramberg─Bäcklund-Reaktion geeignet ist. Zukünftige Arbeiten werden sich darauf konzentrieren, diese Sequenz zu verifizieren und die Synthese bis zum fortgeschrittenen Zwischenprodukt durch (formelle) elektrocyclische Ringöffnung und Kornblum─DeLaMare-Reaktion abzuschließen
Experimental Data of an Articulated Soft Robot with Variable Payloads and Base Orientations
No full text13 real-world datasets of an articulated soft robot which belong to a T-RO article (DOI: https://doi.org/10.1109/TRO.2025.3631818).The data was recorded during research on physics-informed neural networks. The aim was to learn system models that exhibit high accuracy despite system changes after training. For experimental validation, various datasets were recorded using the semi-modular SPONGE (V2) with five joints. SPONGE was published as open source as part of a RA-L article (DOI: 10.1109/LRA.2024.3388855). The publication also described the entire hardware (including sensors and actuators). After publication, improvements were made to the semi-modular robot, resulting in a newer version (V2). All designs are freely available on the corresponding website (https://tlhabich.github.io/sponge/). Both the additional mass at the robot tip and the base orientation of the robot were varied. The data were downsampled to 50 Hz. More detailed information can be found in the corresponding T-RO article.
After attaching a payload (0, 50, 100, or 200g) and setting a base orientation (0, 45, or 90 deg), random input signals (desired pressures of the pneumatic system) were applied with linear transitions during all data recordings. Each .csv file is named using the schema “orientation_Xdeg_payload_Yg_Z”. X indicates the base orientation in degrees, Y indicates the payload in grams, and Z indicates the type of dataset (identification or test). Each file contains the recording of the time, base orientation, payload, five joint angles, five angular velocities, ten measured pressures, and ten desired pressures. The notation was taken from the T-RO article
Herstellung und Charakterisierung von α-emittierenden Umweltstandards – konventionelle Methoden und Radiolumineszenz im Vergleich
No full textBei radiologischen Notfällen, bei denen sich Radionuklide über große Flächen ausgebreitet haben, ist eine schnelle und zuverlässige Methode zur Identifizierung und Lokalisierung dieser erforderlich, um Mensch und Umwelt schützen zu können. Für γ-Emitter existieren bereits Detektionssysteme, die diese Anforderungen erfüllen nicht jedoch für reine α-Emitter. Im Rahmen des Projekts REMOTEALPHA wird ein optisches Detektionssystem entwickelt, das auf dem Phänomen der Radiolumineszenz zur Identifizierung von α-Kontaminationen basiert. Die Eignung des optischen Detektionssystems für Messungen in der Umwelt wird durch Experimente mit Proben aus typischen Umweltmaterialien und dem Vergleich der Ergebnisse mit konventionellen α-Detektionsmethoden bewertet. Als typische Umweltmaterialien wurden Efeublätter und Tannennadeln als Repräsentanten einer Kontamination in der Natur ausgewählt. Für die Repräsentation von urbanen Gegenden wurde Beton ausgewählt, da es in Städten ein häufig vorkommendes anthropogenes Oberflächenmaterial ist.
Diese Dissertation befasst sich mit der Herstellung und Charakterisierung von mit 241Am gespikten Beton- und Pflanzenproben sowie Pechblendeproben. Die Charakterisierung dieser Proben erfolgt mittels konventioneller α-Spektrometrie durch die Verwendung einer Gitterionisationskammer und eines Halbleiterdetektors. Die Kernspurdetektion wird zur ortsaufgelösten Lokalisierung von α-Emittern auf Pechblendeproben eingesetzt. Die α-spektrometrischen Messungen werden durchgeführt, um die Ergebnisse der Messungen der Radiolumineszenzphotonen zu validieren.
Bei den Efeublättern führt die flache und wasserundurchlässige Oberflächenstruktur zu einer guten Übereinstimmung zwischen der aufgetragenen und der gemessenen Aktivität sowohl für die Detektion der α-Teilchen als auch für die der Radiolumineszenzphotonen. Die Geometrie von Tannennadeln auf einem Zweig ist deutlich komplexer, da die Nadeln in verschiedene Richtungen weisen. Dies führt zu einem vergleichsweise geringerem Radiolumineszenz- und α-Spektrometrie-Signal.
Beim Beton ist das beobachtete Verhältnis zwischen aufgetragener und gemessener Aktivität von mehreren Parametern abhängig. Die Wichtigsten sind dabei das Wasser-Zement-Mischungsverhältnis, die Oberflächenrauheit, die Molarität der Tracerlösung sowie das aufgetropfte Flüssigkeitsvolumen, welche in dieser Arbeit untersucht wurden. Die Untersuchung der Stärke des Einflusses dieser Parameter auf das Messergebnis ist notwendig, um die Ergebnisse der Radiolumineszenz- und α-Spektrometrie-Messungen zu interpretieren. Ein hoher Wasseranteil im Beton erzeugt mehr Poren, über welche die Tracerlösung tiefer in den Beton einzieht. Dadurch werden die α-Teilchen im Inneren des Betons emittiert und nicht an der Oberfläche, was zur Verringerung ihrer Energie führt. Eine hohe Oberflächenrauheit und ein größeres Flüssigkeitsvolumen führen ebenfalls zu mehr Absorption. Die saure Tracerlösung (pH-Wert < 0,3) reagiert mit dem basischen Beton, was die Oberfläche stark verändert und dazu führt, dass α-Teilchen im Beton vollständig absorbiert werden. Dadurch steigt die Anzahl an Radiolumineszenzphotonen nicht linear mit steigender Aktivität der Betonprobe an. Diese Ergebnisse können durch konventionelle α-spektrometrische Messungen bestätigt werden.
Um die Empfindlichkeit und die Grenzen des optischen Detektionssystems zu bestimmen, werden Pechblendeproben mit einer geringen Oberflächenaktivität von ca. 1,5 kBq verwendet. Die Messungen der Radiolumineszenzphotonen der Proben werden in einer, mit einem Gemisch aus Stickstoff und Stickoxid gefüllten, Kammer durchgeführt. Messungen in der Raumluft erweisen sich zwar als durchführbar, erfordern jedoch eine mehrtägige Messzeit.In instances of radiological emergencies characterized by the dispersal of radionuclides across large environmental domains, it is necessary to have a rapid and robust method for the detection and localization of these contaminants. Such detection systems already exist for γ-emitters, while purely α-emitting radionuclides are still a challenge to this day. The European project REMOTEALPHA introduces a novel optical detection system that is based on the phenomenon of radioluminescence to identify α-contaminations. The suitability of this optical detection system is assessed through experiments with common environmental materials. Ivy leaves and pine needles, are used as proxy of a contamination in natural areas, whereas concrete is chosen because of its common occurrence as an anthropogenic surface material in urban areas.
This dissertation takes part within REMOTEALPHA and is about the manufacturing and characterization of concrete and plant samples spiked with 241Am, as well as pitchblende samples. The characterization of these samples is done by conventional α-spectrometry, using a grid ionization chamber and a semiconductor detector. α-track-detection is used to spatially locate alpha-emitters on pitchblende samples. The radioluminescence data are validated with results from the methods mentioned above.
Ivy leaves have a flat and impermeable surface structure, which results in a good agreement between applied and measured activity for the α-detection as well as for the radioluminescence detection. The geometry of pine needles is much more complicated, because the needles point in different directions. This results in a comparatively lower radioluminescence and α-spectrometry signal.
For concrete samples the observed ratio between applied activity and measured activity is dependent upon several parameters. The most important ones are the water-cement mixing ratio, the surface roughness, the spiking solution molarity as well as the liquid volume, which are discussed in this work. Understanding the influence of these parameters is important for interpreting the results of radioluminescence and α-spectrometry measurements. A higher amount of water in the concrete produces more pores through which the spiking solution can migrate in deeper inside the concrete. α-particles, which were emitted in the concrete rather than from its surface will lose energy on their way through it. A high surface roughness as well as a large liquid volume lead to more absorption of α-particles. The acidic spiking solution reacts with the basic concrete and changes the sample surface, which leads to an almost total absorption of α-particles. The effect is a non-linear relationship between the number of radioluminescence photons and spiked activity of the concrete sample. However, these results can be confirmed by conventional α-spectrometric measurements.
To benchmark the sensitivity and limits of the optical detection system, pitchblende samples with a low surface activity of approximately 1.5 kBq are used. The measurements of the radioluminescence photons from the samples are accomplished in a gas chamber filled with a mixture of nitrogen and nitric oxide. Measurements in ambient air are feasible, but require several days of measurement
No Words: The Visual Rhetorics of Mosaic and Antienvironment in Steve Lawrence's Avant-Garde Periodical Newspaper (1968-1971)
No full textA newspaper without words is as perplexing as it sounds, but this is precisely the case with Steve Lawrence’s picture periodical Newspaper. I argue that Lawrence disrupts the traditional newsprint medium by engaging with the mosaic’s fragmented, discontinued, and random form that underscores a non-linear and participatory narrative, ultimately positioning the reader as an active co-creator in interpreting the visual chaos. This visual fragmentation mirrors modernist tendencies – expressionism, cubism, and pop art – allowing for multiple entry points for interpretation. As a result, Lawrence constructs Newspaper as an antienvironment that requires the reader to recognize and reveal the invisible structures that govern the art and media environments. Ultimately, this study explores how Newspaper dematerializes its identity as a news medium while resisting the systems it critiques and anticipates shifts in media literacy through its adaptive mosaic format
Graduiertenkolleg „Integrität und Kollaboration in dynamischen Sensornetzen“ : Bausteine für eine verlässliche Navigation im urbanen Bereich
No full text[no abstract available
Ästhetiken der Tyrannis : Figurationen der Gewaltherrschaft vom 18. Jahrhundert bis zur Gegenwart
No full textLiterary tyrant figures and the tyranny as a form of rule are politically and aesthetically constructed. Aesthetics of tyranny are examined in literary texts in connection with aesthetic theories. With the inclusion of state and cultural theories as well as the construction of tyrannical masculinities, texts from the 18th century to the present are analyzed.Tyrannen stehen in Kulturen seit der Antike mit Gewalt, Herrschaft, Willkür und Hybris in Beziehung. Insbesondere ab dem 18. Jahrhundert treten sie in literarischen Texten zudem als narzisstische, gierige und manipulative Männerfiguren in Erscheinung, zeigen sich jedoch auch belehrend oder unbelehrbar und wirken monströs oder kreatürlich