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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

The Systematic Development Process Applied on a Cab Rotation Unit : Pre-study, concept generation, embodiment design, material selection and optimization / Applicering av den systematiska utvecklingsprocessen på en rotationsenhet för hytter : Förstudie, konceptgenerering, designspecificering, materialval och optimering

Gustafsson, Daniel January 2018 (has links)
This master thesis studies and applies the systematic development process. The process is initially described in general, creating a template for the process, and later on applied on a real case scenario to show the performance. Finally eventual advantages, drawbacks and suggestions for future improvements are given. The systematic development approach has been performed at Laxå Special Vehicles, who produce truck cabs and special truck chassis for Scania CV AB. The project has focused on the cabs, i.e. the Crew Cabs and the Low Entry. Crew Cabs are extended normal truck cabs, containing four doors to make additional passengers possible, suitable for fire trucks etc. Low Entry is a lowered normal truck cab, lowering the approaching height, making this cab type suitable for city applicable usage where the driver or passengers enter and leave the cab frequently. The task given was to develop the current cab rotation unit to be able to handle both cabs, which from the beginning only could handle the Crew Cabs, called CC28 and CC31. The major goal of this project has been to enable rotation of the Low Entry too. Five phases – pre-study, concept generation, embodiment design, material selection and optimization – were carried out. The pre-study generated a fundamental base of knowledge, according to both the systematic development process and information about the tilt. The concept generation contained a problem degradation, generation of possible solutions and finally an evaluation of these. During the embodiment design the best suited concept was described and developed in detail to allow a suitable material to be selected during the material selection phase. The optimization process consisted of investigating properties according to mechanical strength and stiffness. Two construction solutions to accommodate the mounting points height and length difference between the Crew Cab and the Low Entry were developed. These were a covering plate, called K4, and a mounting plate, called K100, handling the problems occurring for length and height respective. The development process is thus considered to be well operating. It generated a useful result, although possibilities for further improvements exists. / Denna masteruppsats studerar och förklarar den systematiska utvecklingsprocessen. Processens olika steg beskrivs inledningsvis generellt, för att sedan appliceras på ett reellt fall för att demonstrera genomförandet. Avslutningsvis ges fördelar, nackdelar och eventuella förbättringsförslag på metoden. Projektet genomfördes på Laxå Special Vehicles som producerar hytter och chassin för fordonstillverkaren Scania. Projektet fokuserade på hytterna som kallas Crew Cab och Low Entry, där den först nämnda är en förlängd hytt med fyra dörrar istället för två. Detta ger mer hyttutrymme, plats för fler passagerare och är därför vanlig i tillämpningar som till exempel brandbilar. Low Entry är en tvådörrarshytt vars insteg är lägre än för vanliga tvådörrarshytter, vilket gör den användbara i stadsnära miljöer där passagerare eller förare ofta lämnar och går in i hytten. Uppgiften som skulle lösas, och därmed målet, var att anpassa en rotationsenehet, även kallad tilt, för även kunna rotera LE. Ursprungligen var den endast anpassad för de två hyttvarianterna av Crew Cab, som kallas CC28 och CC31. Arbetet behandlade fem faser – förstudie, konceptgenerering, designspecificering, materialval och optimering – vilka skulle genomföras för att nå ett användbart resultat. Förstudien fokuserade på att erhålla kunskap om den systematiska utvecklingsprocessen, hur denna skulle genomföras, samt information om hur rotationsenheten fungerade. Konceptgenerering innehöll en problemnedbrytning, konceptskapande och utvärdering av de genererade koncepten. Under designspecificeringen gavs det bästa konceptet/koncepten dimensioner och specificerade funktioner för att under materialvalsprocessen erhålla passande material. Under optimeringsfasen genomfördes analysering och optimering, med avseende på styrka och styvhet. Två konstruktionslösningar utvecklades vilka löste var sitt delproblem som var höjd- och längdskillnad för den bakre monteringspunkten mellan Crew Cab och Low Entry. En omgjord monteringsplatta visade sig lösa höjdskillnaden bäst, kallad K100. Längdskillnaden togs om hand genom att applicera en längre glidskena som skulle täckas av luckor, kallade K4. Eftersom ett väl fungerande resultat erhållits visade den systematiska utvecklingsprocessen sig fungera som efterfrågat men med förbättringspotential.
22

Retractable Boarding Step to Scania Crew Cab : Product Development, Design, FEM Simulations and Verification / Utfällbart insteg till Scania Crew Cab lastbilar : Produktutveckling, konstruktion, FEM simulering och verifikation

Möllberg, Nadine January 2017 (has links)
This master thesis treats the development of a new solution for a retractable boarding step to Scania trucks, which is a part of the modular system. Some customers have the need to transport additional passengers. For such applications, Scania provides trucks featuring a Crew Cab, which is an extended cab with rear doors. Easy exit through the rear doors is important for many customers who use this type of cabin. Therefore, there is a possibility to get a retractable boarding step, equipped with an upper step and a lower foldable, that enables easy entry and exit. This function is especially important for fire fighters carrying heavy equipment and therefore has more difficulties exiting the truck. The robustness and dependability of the function is critical to ensure the safety. If it fails, the legal requirements are not met while driving or even worse, injury may occur. Pneumatics is used for the fold out of the step and a spring folds it in. The current boarding step needs improvement in order for it to be dependable and robust. If the boarding step have not been folded out, the entry and exit of the cab is not possible. This thesis covers the product development, simulations and verification of a new boarding step concept that shall improve the entry- and exit function, making it more robust and dependable. Through problem identification, a product specification and a thorough concept generation and development process a final concept has produced. Simulations were made in order to verify that the step could be stepped on when entering and exiting the cab. The result was a lower step, sliding on linear bearings in a linear motion. This enabled egress and ingress independent of the extraction or retraction of the step. This makes it more reliable than the current product. The sliding mechanism need to be tested in order to ensure the robustness. A prototype was made in order for the function to be tested. / Detta examensarbete behandlar utvecklingen av en ny lösning för ett fällbart insteg till Scania lastbilar, som är ett modular product Scania utvecklar lastbilar till ett brett spektrum av tillämpningar. Behov av att transportera ytterligare passagerare kan finnas. För sådana tillämpningar erbjuder Scania specialfordon med manskapshytt, en förlängd hytt med bakdörrar. Enkel urstigning genom bakdörrarna är viktigt för många kunder som utnyttjar denna typ av hytt. Därför finns möjligheten att få ett utfällbart steg som förenklar in- och urstigning, utrustad med ett fast övre steg och ett fällbart nedre. Detta är särskilt viktigt för brandmän som bär tung utrustning och därför har svårare att ta sig ur bilen. Det utfällbara steget fälls ut för enkel åtkomst när det behövs och viks in under körning. Detta för att uppfylla lagkrav för fordonsbredd. Tryckluft används för att fälla ut steget och en fjäder används för att fälla in det. Flera fall där problem gällande in- och utfällningsmekanism har påvisats, fälls inte steget ut är det inte möjligt att stiga i och ur hytten. Förbättring av robusthet och pålitlighet behövs genomföras. Examensarbetet ska förbättra instignings- och urstigningsfunktionen och se till att den är robust och pålitlig.Genom att identifiera problemet, upprätta en produktspecifikation och genomföra en grundlig konceptgenerering och utvecklingsprocess har ett slutgiltigt koncept tagits fram.  FEM simuleringar gjordes för att kunna verifiera att insteget håller för att kliva på. Resultatet blev ett undre steg, som glider på linjärlager. Detta möjliggör i och urstigning oberoende av i vilket läge steget är. Det gör den mer tillförlitlig än dagens produkt. Glidmekanismen måste testas för att kunna säkerställa dess robusthet. En prototyp har tillverkats för att testa detta.
23

Vývoj psychosociální dynamiky týmů v izolaci / Development of psychosocial dynamics of teams in isolation

Davidová, Lucie January 2019 (has links)
The thesis focuses on psychosocial dynamics of teams in isolation and its development over time. Literature review summarises various psychosocial and psychological aspects of human coexistence in extreme environments. It includes the risks and psychological countermeasures, description of stressors and other challenges, the intragroup issues and their development over time. It puts emphasis on defining the most challenging parts of missions and tries to identify patterns. Additionally, the relationship between the crew and MCC is addressed. The literature review is followed by a study focused on the development of intragroup relations and the crew-MCC relations in two analogue missions, Lunar Expedition-0 and Lunar Expedition-1. The research design consisted of a questionnaire, an interview with the whole crew, and the individual interviews with all respective astronauts. Additionally, a new visualization method, Dotty Overview of Team Interactions (DOTI), has been created as a part of this research. DOTI was described and used to visualize the data relating mutual interactions among the crewmembers. All of the results are presented, described and discussed. Keywords: team dynamics, crew, analogue space missions, interactions, relationship between crew and mission control
24

Development of simulation-based genetic algorithms model for crew allocation in the precast industry

Al-Bazi, Ammar F. J. January 2010 (has links)
The focus of this thesis is on the precast concrete products manufacturing industry, which as one of the labour-intensive industries requires a substantial number of highly skilled operators in terms of crews to produce the final product. A crew is a group of multi-skilled chargehands and operators that have various skills and experience necessary to conduct an activity in a professional way. The high cost of skilled operators and the apparent inefficiencies of utilising such skilled operators in the industry are the major driving force. To achieve this, optimal crew allocation is required. Crew allocation is complex because of the multi-criteria nature of the problem and availability of thousands of possibilities and allocation alternatives. There is a gap in previous research efforts associated with crew allocation planning in the precast industry. Current practices suggest that the crew allocation process is carried out intuitively and the allocation of crews to production processes is subjective. This has led to high process-waiting times, improper allocation of skilled operators and ultimately higher production costs. In this context, the aim of this research is to propose an effective crew allocation methodology and a computer-based intelligent simulation model for its implementation. The objective of the approach is to guarantee a better workflow through minimising process-waiting time, optimising operator utilisation, and subsequently reducing the allocation cost. This research develops a holistic and integrated methodology for modelling crew allocation problems by reviewing state-of-art resource allocation techniques, structured interviews with production managers, site visits and a detailed case study. The methodology is developed using an IDEF0 process model and a generic process map for both the business and the production processes of the precast manufacturing system. A multi-layered genetic algorithm model is developed in conjunction with a process-simulation model to form a hybrid allocation system dubbed ‘SIM_Crew’. The model incorporates databases (Excel and MS Access), a simulation model (developed using Arena 12.0) and genetic algorithms (developed using Visual Basic for Applications) to facilitate the generation and evaluation of various “what-if” crew allocation scenarios. A number of performance criteria have been developed to evaluate the allocation plans. ‘SIM_Crew’ enables the investigation and analysis of allocating possible schedules and provides a facility to visualise the production processes. ‘SIM_Crew’ was validated using real life case study data and it was concluded that the allocation of crews to precast processes using genetic algorithm improves the throughput time and reduces the allocation cost as compared with real life production data. It is anticipated that future use of this research will solve the crew allocation problem in the precast industry.
25

Vývoj struktury a dynamiky vztahů a vazeb mezi členy posádky v průběhu simulace kosmického letu / Development of the dynamics and structure of relationships in the crew during simulated space flight

Tefelnerová, Pavla January 2019 (has links)
Work of groups in the extreme, isolated and confined environment relates to the high risks and demands as well. One of the groups working in that specific conditions are the space crews. Attention has been focused recently on preventing the risk of their failure. For a successful fulfilment of the space missions, it seems that the relations between the crew members are crucial. They manifest in various areas: communication, cooperation, group cohesion, mutual trust, support and others. The theoretical part of this thesis describes selected factors related to interpersonal relationships. Two groups of factors are discussed - factors connected with a diversity of the crew and the and the situational factors. There is a discussion of the methods used for measuring and assessing the interpersonal relations, their advantages and limitations. As a follow-up to this part, socio-diagnostic method called "sociomapping" is described in detail because of its use in the empirical part of the thesis. The goal of the empirical part is to analyse two areas: the development of the group dynamics during a mission and the connection between the gender-mixed crew and the tendency to creating the subgroups. Previous research show ambiguity in the research findings. For this purpose, data from 17-day simulation of the...
26

Uma análise das normas brasileiras de habitabilidade e segurança para os alojamentos das embarcações / An analysis of brazilian standards of habitability and safety of ships\' crew accommodation

Toniolo, João Fabio Mariotto 28 April 2014 (has links)
Esta dissertação de mestrado apresenta os resultados de uma pesquisa que buscou verificar se as normas vigentes no Brasil para os alojamentos dos tripulantes de navios mercantes são efetivas em propiciar boas condições de habitabilidade e segurança. O processo utilizado para esta verificação foi o de comparar tais normas com recomendações e determinações de diversas fontes. A opção por este objeto de pesquisa se justifica uma vez que atualmente, após mais de duas décadas de decadência da indústria naval e da frota mercante brasileiras, há um grande número de navios em construção. Além disso, a vida útil dos navios é de aproximadamente trinta anos, o que significa que a inadequação das normas segundo as quais são construídos implicaria em consequências de longo prazo e difíceis de serem revertidas, em função da complexidade dos navios. Por outro lado, a Organização Marítima Internacional e outras fontes citam o projeto dos alojamentos como um dos fatores que podem influenciar no aumento do número de casos e na intensidade da fadiga entre os tripulantes, com reflexos na incidência de erros humanos e, consequentemente, de acidentes marítimos. Um indicador da existência de deficiências na configuração dos espaços de alojamento é o número de acidentes pessoais neles ocorridos, relativamente alto quando comparado com o das áreas de trabalho e operação da embarcação, onde o risco de acidentes é consideravelmente maior. A confrontação das normas vigentes no Brasil com recomendações e determinações das diversas fontes consultadas evidenciou que estas admitem condições mais desfavoráveis do que as aceitas para embarcações destinadas a fins especiais e em navios de algumas marinhas de guerra. Ademais, sua análise revelou que não especificam os níveis considerados apropriados ao conforto térmico, acústico, iluminação e vibrações, o que indica que estão desatualizadas e aponta para a necessidade de sua revisão com base em estudos atuais. / This Master\'s dissertation presents the results of research which seeks to establish whether the prevailing standards for crew accommodation in merchant shipping in Brazil is effective in providing good conditions of habitability and safety. The verification process used was to compare such standards with recommendations and requirements from several different sources. The justification for this choice of research is that following more than two decades of decline in the shipbuilding sector and the Brazilian merchant navy, there are now a large number of ships once more under construction in indigenous shipyards. Since ships have a useful life of approximately thirty years, this means failure to adhere to construction standards would imply long term consequences, difficult to revert in the light of the complexity of vessels. Conversely, the International Maritime Organization as well as other sources, cites the onboard accommodation project as one of the factors that can impact the number of cases of fatigue and its intensity among crew members. This in turn is reflected in the level of human error and consequently, maritime accidents. One indicator of deficiencies in accommodation configuration is the number of personal accidents that occur in them, relatively high compared with onboard working and operational areas where risk of accidents is considerably greater. The comparison of the prevailing standards in Brazil with recommendations and requirements of several sources which have been consulted, revealed that these tolerate conditions which are less favorable than those acceptable in special purpose vessels and in the ships of some navies. Additionally, comparison showed that standards prevailing in Brazil fail to specify the levels deemed appropriate for thermal and acoustic comfort, lighting and vibration. The indication is that such are out-of-date - pointing to a need for review based on current studies.
27

Decision Support for Crew Scheduling using Automated Planning

January 2019 (has links)
abstract: Allocating tasks for a day's or week's schedule is known to be a challenging and difficult problem. The problem intensifies by many folds in multi-agent settings. A planner or group of planners who decide such kind of task association schedule must have a comprehensive perspective on (1) the entire array of tasks to be scheduled (2) idea on constraints like importance cum order of tasks and (3) the individual abilities of the operators. One example of such kind of scheduling is the crew scheduling done for astronauts who will spend time at International Space Station (ISS). The schedule for the crew of ISS is decided before the mission starts. Human planners take part in the decision-making process to determine the timing of activities for multiple days for multiple crew members at ISS. Given the unpredictability of individual assignments and limitations identified with the various operators, deciding upon a satisfactory timetable is a challenging task. The objective of the current work is to develop an automated decision assistant that would assist human planners in coming up with an acceptable task schedule for the crew. At the same time, the decision assistant will also ensure that human planners are always in the driver's seat throughout this process of decision-making. The decision assistant will make use of automated planning technology to assist human planners. The guidelines of Naturalistic Decision Making (NDM) and the Human-In-The -Loop decision making were followed to make sure that the human is always in the driver's seat. The use cases considered are standard situations which come up during decision-making in crew-scheduling. The effectiveness of automated decision assistance was evaluated by setting it up for domain experts on a comparable domain of scheduling courses for master students. The results of the user study evaluating the effectiveness of automated decision support were subsequently published. / Dissertation/Thesis / Masters Thesis Computer Science 2019
28

Flight deck crew coordination indices of workload and situation awareness in terminal operations

Ellis, Kyle Kent Edward 01 July 2014 (has links)
Crew coordination in the context of aviation is a specifically choreographed set of tasks performed by each pilot, defined for each phase of flight. Based on the constructs of effective Crew Resource Management and SOPs for each phase of flight, a shared understanding of crew workload and task responsibility is considered representative of well-coordinated crews. Nominal behavior is therefore defined by SOPs and CRM theory, detectable through pilot eye-scan. This research investigates the relationship between the eye-scan exhibited by each pilot and the level of coordination between crewmembers. Crew coordination was evaluated based on each pilot's understanding of the other crewmember's workload. By contrasting each pilot's workload-understanding, crew coordination was measured as the summed absolute difference of each pilot's understanding of the other crewmember's reported workload, resulting in a crew coordination index. The crew coordination index rates crew coordination on a scale ranging across Excellent, Good, Fair and Poor. Eye-scan behavior metrics were found to reliably identify a reduction in crew coordination. Additionally, crew coordination was successfully characterized by eye-scan behavior data using machine learning classification methods. Identifying eye-scan behaviors on the flight deck indicative of reduced crew coordination can be used to inform training programs and design enhanced avionics that improve the overall coordination between the crewmembers and the flight deck interface. Additionally, characterization of crew coordination can be used to develop methods to increase shared situation awareness and crew coordination to reduce operational and flight technical errors. Ultimately, the ability to reduce operational and flight technical errors made by pilot crews improves the safety of aviation.
29

MSC Adams modelling of mechanical system in A400M Crew Entrance Door

Lindberg, David January 2012 (has links)
Saab Aerostructures has developed the Crew Entrance Door (CED) for Airbus A400M. Airbus has decided some different load cases for which the Crew Entrance Door must be built to withstand without something breaking down. The door is maneuvered by a mechanical system and the load cases are essential for the sizing of the components in the mechanical system. Saab has previously used MS Excel to analytically calculate resulting forces in the mechanical system due to external and/or internal loads in the different load cases. This report describes how the mechanical system for A400M Crew Entrance Door instead can be modeled and solved numerically with the computer program MSC Adams/View. Creating a model of a mechanical system in MSC Adams/View proved to be easy and fairly quick. The benefit of working with MSC Adams instead of MS Excel is that it is quicker and more user friendly. The major differences when comparing results were believed to be an effect of comparing results from a kinematic model with results from a dynamic model. Therefore it is in the Authors opinion that the analytical method to calculate resulting forces with MS Excel can be replaced by numerical calculations with MSC Adams/View. However, apart from calculating reaction forces there are additional post-simulation calculations for which it is perhaps more beneficial to use MS Excel. To do these post-simulation calculations in MS Excel it is easy to use exported results from MSC Adams. If Saab Aerostructures decide to start working with MSC Adams/View and if Saab wants geometry to be imported to the model, then an advise from the Author is to have a software installed which can convert step-files (*.stp or *.step) to the MSC Adams preferred file format Parasolid (*.xmt_txt or *.x_t). The software should also be able to repair geometry which will greatly increase mass accuracy.
30

Airline Integrated Planning and Operations

Gao, Chunhua 09 May 2007 (has links)
Efficient integrated/robust planning and recovery models were studied. The research focus was to integrate fleet assignment and crew scheduling, and, in addition, to provide solutions robust to real time operations. The contributions include: (1) To understand how schedule development and fleet assignment stages influence crew scheduling performance, schedule analysis methods were proposed to evaluate the crew friendliness of a schedule for a given fleet. (2) To meet the computational challenges of crew scheduling in integrated planning, a duty flow model was proposed which can efficiently find suboptimal legal pairing solutions. (3) A new robust crew scheduling method based on spoke purity was proposed. Computational results indicated that with little or no extra cost, a more robust crew pairing solutions can be expected. (4) By imposing station purity, an integrated and robust planning model which integrates fleet assignment and crew connections was proposed. The impact of crew base purities and fleet purities on FAM profit, crew scheduling, and computational efficiency were investigated. (5) Airline integrated recovery method was studied. A recovery scope for integrated recovery was proposed to limit the ripple effect caused by disruptions. Based on the defined recovery scope, a new integrated recovery model and Bender¡¯s decomposition solution approach was studied.

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