306 research outputs found
SIMULATING CONSUMABLE ORDER FULFILLMENT VIA ADDITIVE MANUFACTURING TECHNOLOGIES
Operational availability of naval aircraft through material readiness is critical to ensuring combat power. Supportability of aircraft is a crucial aspect of readiness, influenced by several factors including access to 9B Cognizance Code (COG) aviation consumable repair parts at various supply echelons. Rapidly evolving additive manufacturing (AM) technologies are transforming supply chain dynamics and the traditional aircraft supportability construct. As of June 2022, there are 595 AM assets within the Navy’s inventory—all for research and development purposes. This report simulates 9B COG aviation consumable fulfillment strategies within the U.S. Indo-Pacific sustainment network for a three-year span, inclusive of traditional supply support avenues and a developed set of user-variable capability inputs. Simulated probabilistic demand configurations are modeled from historical trends that exploit a heuristic methodology to assign a “printability” score to each 9B COG requirement, accounting for uncertainty, machine failure rates, and other continuous characteristics of the simulated orders. The results measure simulated lead time across diverse planning horizons in both current and varied operationalized AM sustainment network configurations. This research indicates a measurable lead time reduction of approximately 10% across all 9B order lead times when AM is employed as an order fulfillment source for only 0.5% of orders.NPS Naval Research ProgramThis project was funded in part by the NPS Naval Research Program.Lieutenant Commander, United States NavyApproved for public release. Distribution is unlimited
Synthesizing FDIR Recovery Strategies for Space Systems
Dynamic Fault Trees (DFTs) are powerful tools to drive the design of fault tolerant systems. However, semantic pitfalls limit their practical utility for interconnected systems that require complex recovery strategies to maximize their reliability. This thesis discusses the shortcomings of DFTs in the context of analyzing Fault Detection, Isolation and Recovery (FDIR) concepts with a particular focus on the needs of space systems. To tackle these shortcomings, we introduce an inherently non-deterministic model for DFTs. Deterministic recovery strategies are synthesized by transforming these non-deterministic DFTs into Markov automata that represent all possible choices between recovery actions. From the corresponding scheduler, optimized to maximize a given RAMS (Reliability, Availability, Maintainability and Safety) metric, an optimal recovery strategy can then be derived and represented by a model we call recovery automaton. We discuss dedicated techniques for reducing the state space of this recovery automaton and analyze their soundness and completeness. Moreover, modularized approaches to handle the complexity added by the state-based transformation approach are discussed. Furthermore, we consider the non-deterministic approach in a partially observable setting and propose an approach to lift the model for the fully observable case. We give an implementation of our approach within the Model-Based Systems Engineering (MBSE) framework Virtual Satellite. Finally, the implementation is evaluated based on the FFORT benchmark. The results show that basic non-deterministic DFTs generally scale well. However, we also found that semantically enriched non-deterministic DFTs employing repair or delayed observability mechanisms pose a challenge
COVID-2019 Impacts on Education Systems and Future of Higher Education
The rapid outbreak of the COVID-19 has presented unprecedented challenges on education systems. Closing schools and universities and cancelling face-to-face activities have become a COVID-19 inevitable reality in most parts of the world. To be business-as-usual, many higher education providers have taken steps toward digital transformation, and implementing a range of remote teaching, learning and assessment approaches. This book provides timely research on COVID-19 impacts on education systems and seeks to bring together scholars, educators, policymakers and practitioners to collectively and critically identify, investigate and share best practices that lead to rethinking and reframing the way we deliver education in future
Study of the electrical system of a commercial aircraft: development of a numerical simulation model
The need of electric power on aircraft has been growing from few VA of the engine ignition system of early aircraft such as the Wright flyer to almost 1 MVA for large long range commercial aircraft as for example the B747 or the A380. As aircraft is becoming more electric, the electric power system becomes increasingly critical.
For this project I managed to study and develop a simulation model of the electrical system of a commercial aircraft, exactly based on the Airbus A320, to be used in electrical engineering and aerospace engineering courses in the near future
The EBMT Handbook
This Open Access edition of the European Society for Blood and Marrow Transplantation (EBMT) handbook addresses the latest developments and innovations in hematopoietic stem cell transplantation and cellular therapy. Consisting of 93 chapters, it has been written by 175 leading experts in the field. Discussing all types of stem cell and bone marrow transplantation, including haplo-identical stem cell and cord blood transplantation, it also covers the indications for transplantation, the management of early and late complications as well as the new and rapidly evolving field of cellular therapies. This book provides an unparalleled description of current practices to enhance readers’ knowledge and practice skills
Underwater Vehicles
For the latest twenty to thirty years, a significant number of AUVs has been created for the solving of wide spectrum of scientific and applied tasks of ocean development and research. For the short time period the AUVs have shown the efficiency at performance of complex search and inspection works and opened a number of new important applications. Initially the information about AUVs had mainly review-advertising character but now more attention is paid to practical achievements, problems and systems technologies. AUVs are losing their prototype status and have become a fully operational, reliable and effective tool and modern multi-purpose AUVs represent the new class of underwater robotic objects with inherent tasks and practical applications, particular features of technology, systems structure and functional properties
An Architecture for the Integration of Human Workers into an Industry 4.0 Manufacturing Environment.
Thesis (PhD)--Stellenbosch University, 2021.ENGLISH SUMMARY: With the rise of Industry 4.0 and the development in technologies that contribute to this revolution in manufacturing, research has focused mainly on the machines and automated digital systems contributing to the manufacturing environment. Humans are still critical to manufacturing; offering unmatched ingenuity, robustness, and flexibility despite their apparent disadvantages in strength or precision. Many successful manufacturing firms still include humans in their manufacturing processes for these reasons, and it is critical that the integration of humans in an I4.0 manufacturing environment is given research attention.
This dissertation first explores the requirements for the integration of human workers into an I4.0 environment. It was determined that the largest problem with human integration exists with data related to the human being digitised, managed, and communicated with other entities in processes that are identified as Administrative Logistics. It is identified that an administration shell similar to the RAMI4.0 administration shell concept is required to manage these Administrative Logistics on behalf of the human, and that a holonic systems approach is beneficial. The dissertation then proposes the concept of a Human Resource Holon Administration shell (HRH-AS).
An architecture to implement such an administration shell is then developed, here named the BASE architecture. This administration shell facilitates the interfacing, data processing, and connectivity to other I4.0 components on behalf of the human, to aid in their integration to the digital factory environment around them.
The BASE architecture addresses three identified responsibilities of such an administration shell, namely interfacing, digital data management, and delegation to other I4.0 components. BASE stands for Biography, Attributes, Schedule, and Execution, and is a time-based separation of concerns for key augmentations provided to the human worker. The BASE architecture separates value-adding and decision-making plugin components, which are specific to an application, from the core components, which are generic to any application.
The BASE architecture led to the development of the 3SAL activity structure to facilitate the communication and management of industrial activities in a digital environment.
With the help of an industry partner, two case studies were developed to evaluate an implementation of the BASE architecture. The company is an aerospace composites manufacturer and was chosen for the labour-intensive requirements of the composites industry. The case studies aimed to evaluate the architecture against the three identified administration shell responsibilities and determine if the human workers are elevated to resource holon status. The first case study aimed to show how BASE facilitates interfacing with humans in an I4.0 environment and also acted as a technology demonstrator for the second case study. The second case study evaluated the effect BASE had on the Administrative Logistics involved in the business processes workers were involved in. Together these case studies fully evaluate BASE’s ability to facilitate the integration of humans into an I4.0 manufacturing environment through identified responsibilities of the administration shell.
The evaluation found that the BASE HRH-AS improves the effectiveness of Administrative Logistics of business processes the human workers were involved with, as well as opened new opportunities for decision making on the shop floor previously not possible. Value-adding, by means of the plug-in components of a BASE administration shell, has also been proven by the ability to do automated schedule management, automatic calculation of standard work and improved traceability using the 3SAL activity structure.AFRIKAANS OPSOMMING: Met die opkoms van Industrie 4.0 (I4.0) en die ontwikkeling in tegnologieë wat bydra tot hierdie revolusie in vervaardiging, het navorsing grotendeels gefokus op die masjiene en digitale stelsels wat tot die vervaardigingsomgewing bydra. Menslike werkers is steeds van kritieke belang vir vervaardiging, en bied ongeëwenaarde vindingrykheid, robuustheid en buigsaamheid, ondanks hul oënskynlike nadele in sterkte of noukeurigheid. Baie suksesvolle vervaardigingsondernemings sluit nogsteeds mense in hul vervaardigingsprosesse in om hierdie redes. Dit is dus noodsaaklik dat die integrasie van mense met 'n I4.0 vervaardigingsomgewing navorsingsaandag geniet.
Hierdie verhandeling ondersoek eerstens die vereistes vir die integrasie van menslike werkers in 'n I4.0 omgewing. Daar word eerstens geïdentifiseer dat die grootste probleem met die integrasie van mense bestaan uit oneffektiewe prosesse wat data en informasie tussen mense en ander komponente in die vervaardigingsprosesse komminikeer, stoor en bestuur. Hierdie prosesse word na verwys as Administratiewe Logistieke. Daar word ook geïdentifiseer dat 'n administrasie-dop soortgelyk aan die RAMI4.0 administrasie-dop konsep benodig word om Administratiewe Logistieke te bestuur namens die mens, en dat 'n holoniese stelselbenadering voordelig is. Die verhandeling stel dan die konsep van 'n Human Resource Holon Administration Shell (HRH-AS) voor.
Daarna word 'n argitektuur ontwikkel om so 'n administrasie-dop te implementeer, hier genoem die BASE argitektuur. Hierdie administrasie-dop vergemaklik die inskakeling, dataverwerking en konnektiwiteit met ander I4.0 komponente namens die mens. Die integrasie van die mens in die digitale fabrieksomgewing is dus bevoordeel.
Die BASE argitektuur spreek drie geïdentifiseerde verantwoordelikhede van so 'n administrasie-dop aan, naamlik: koppelling met die mens, digitale databestuur, en delegering na ander I4.0 komponente namens die mens. BASE staan vir Biography, Attributes, Schedule en Execution, en is 'n tydgebaseerde skeiding van belange vir aanvullings wat aan die menslike werker verskaf word. Die BASE argitektuur skei waardetoevoeging- en besluitneming-inpropkomponente, wat spesifiek vir 'n toepassing is, van die kernkomponente, wat generies is vir enige toepassing.
Die BASE argitektuur het gelei tot die ontwikkeling van die 3SAL aktiwiteitstruktuur om die kommunikasie en bestuur van industriële aktiwiteite in 'n digitale omgewing te vergemaklik.
Met die hulp van 'n bedryfsvennoot is twee gevallestudies ontwikkel om 'n implementering van die BASE argitektuur te evalueer. Die maatskappy is 'n lugvaart saamgestelde-mater komponent vervaardiger en is gekies vir die arbeidsintensiewe vereistes van die saamgestelde-mater bedryf. Die gevallestudies was daarop gemik om die argitektuur teen die drie geïdentifiseerde verantwoordelikhede van die administrasiedop te evalueer en te bepaal of die menslike werkers verhoog word tot holon status. Die eerste gevallestudie se doel was om te wys hoe BASE n koppelvlak tussen mense en digitale stelsels toelaat. Die eerste gevallestudie was ook 'n demonstrasie dat 'n toepassing in die bedryfsvenoot se fabriek toegepas kon word vir die tweede gevallestudie.
Die tweede gevallestudie het die effek geëvalueer wat BASE het op die Administratiewe Logistiek betrokke by die besigheidsprosesse waarby werkers betrokke was. Saam evalueer hierdie gevallestudies BASE se vermoë om die integrasie van mense in 'n I4.0 vervaardigingsomgewing te fasiliteer deur geïdentifiseerde verantwoordelikhede van die administrasiedop. Die evaluering het bevind dat die BASE HRH-AS die doeltreffendheid van Administratiewe Logistiek van besigheidsprosesse wat menslike werkers benut, asook nuwe geleenthede vir besluitneming op die winkelvloer, verbeter tot n mate wat voorheen nie moontlik was nie. Waarde-toevoeging, deur middel van die inpropkomponente van 'n BASE administrasie dop, is ook bewys deur die vermoë om outomatiese skedule-bestuur, outomatiese berekening van standaardwerk en verbeterde naspeurbaarheid met behulp van die 3SAL-aktiwiteitsstruktuur te doen.Doctora
- …