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1 – 4 of 4Roberta Fusaro and Nicole Viola
This paper aims to propose a methodology for a safety and reliability assessment for the conceptual and preliminary design of very complex and disrupting innovative systems like…
Abstract
Purpose
This paper aims to propose a methodology for a safety and reliability assessment for the conceptual and preliminary design of very complex and disrupting innovative systems like trans-atmospheric vehicles. The proposed methodology differs from existing ones because it does not rely on statistical data at aircraft-level but exploits the statistical population at components-level only. For the sake of clarity, the paper provides some preliminary results of the application of the methodology at system level. The example deals with the safety and reliability assessment of a very complex propulsion system aimed at guaranteeing vertical take-off and landing capabilities of a suborbital vehicle.
Design/methodology/approach
The proposed methodology is strongly based on a systems engineering approach. It exploits safety and reliability assessment analyses which have already been developed in both aeronautical and space engineering domains, but it combines them in an innovative way to overcome the lack of statistics at aircraft level. The methodology consists of two different steps: a qualitative top-down process, allowing a functional and physical decomposition of the transportation system and a following quantitative bottom-up approach, which provides the estimation of system-level reliability and safety characteristics starting from the statistical estimation of the components’ characteristics.
Findings
The paper presents a new methodology for the preliminary reliability and safety assessment of innovative transportation systems, such as hypersonic transportation systems. The envisaged methodology will overcome the poorness of statistical data that is usually affecting the conceptual design of breakthrough systems.
Research limitations/implications
The paper shows the application of the articulated methodology to a limited case study. A complete example of application of the methodology to estimate safety and reliability characteristics at vehicle level will be provided in feature works.
Practical implications
The methodology has been proposed to be exploited in international research activities in the field of hypersonic transportation systems. Furthermore, a massive application of this approach would allow to create a database for the generation and the update of semi-empirical models focused on high-level estimations of reliability, availability, maintainability and safety (RAMS) characteristics. Moreover, the proposed safety assessment has been conceived to be fully integrated within a typical conceptual design process.
Originality/value
The existing literature about safety and reliability assessment at the early design stages proposes pure statistical approaches which are usually not applicable to highly innovative products, where the statistical population is not existing, for example, in the case of trans-atmospheric vehicles. This paper describes how to overcome this problem, through the exploitation of statistical data at components-level only through the combination of these data to estimate RAMS characteristics at aircraft-level thanks to functional analysis, concept of operations and typical safety assessment tools, like functional hazard analysis, failure mode and effect analysis, reliability block diagram and fault tree analysis.
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Roberta Fusaro, Nicole Viola, Sara Cresto Aleina and Giovanni Antonio Di Meo
This paper aims to suggest feasible solutions to overcome the problem of unmanned aerial vehicles integration within the existing airspace.
Abstract
Purpose
This paper aims to suggest feasible solutions to overcome the problem of unmanned aerial vehicles integration within the existing airspace.
Design/methodology/approach
It envisages innovative time-based separation procedures that will enhance the integration in the future air traffic management (ATM) system of next generation of large remotely piloted aircraft system (RPAS). 4D navigation and dynamic mobile area concepts, both proposed in the framework of Single European Sky ATM Research program, are brought together to hypothesize innovative time-based separation procedures aiming at promoting integration of RPAS in the future ATM system.
Findings
Benefits of proposed procedures, mainly evaluated in terms of volume reduction of segregated airspace, are quantitatively analyzed on the basis of realistic operational scenarios focusing on monitoring activities in both nominal and emergency conditions. Eventually, the major limits of time-based separation for RPAS are investigated.
Practical implications
The implementation of the envisaged procedures will be a key enabler in RPAS integration in future ATM integration.
Originality/value
In the current ATM scenario, separation of RPAS from air traffic is ensured by segregating a large amount of airspace areas with fixed dimensions, dramatically limiting the activities of these vehicles.
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Sergio Chiesa, Marco Fioriti and Roberta Fusaro
The purpose of this paper is to present a definition of modern configuration for a medium-altitude long-endurance unmanned aerial vehicle (MALE UAV) and its on-board systems to…
Abstract
Purpose
The purpose of this paper is to present a definition of modern configuration for a medium-altitude long-endurance unmanned aerial vehicle (MALE UAV) and its on-board systems to obtain a suitable basis for future definitions such as a possible logistic support configuration first hypothesis.
Design/methodology/approach
Starting from high-level requirements, both the UAV conceptual design and on-board systems preliminary design have been carried out through proprietary tools. Then, some peculiarities from previous studies, such as systems advanced UAV alternative energy, have been maintained and confirmed (diesel propulsion and energy storage system).
Findings
The improvement of a component of an aircraft can play a relevant role in the whole system. In the paper, it is considered how a concept of MALE UAV can evolve (this topic is considered by the authors since many years) by incorporating advanced on-board systems concepts.
Practical implications
The numerical results promote and support the use of advanced on-board system solutions and architectures to improve the effectiveness, efficiency and performance of MALE UAVs.
Originality/value
Usually, conceptual and preliminary design phases analyze in-depth the aerodynamic and structural solutions and aircraft performance. In this study, the authors aim to focus on the advanced on-board systems for MALE UAVs. This kind of aircraft is not yet a mature concept, with very few operating machines and many projects in the development phase.
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Anne Coughlan and Erica Goldman
Mary Kay is one of the best-known direct sellers of women's cosmetics in the world. Its channel strategy is to use independent beauty consultants, who are independent…
Abstract
Mary Kay is one of the best-known direct sellers of women's cosmetics in the world. Its channel strategy is to use independent beauty consultants, who are independent distributors, to sell directly to consumers. Its compensation plan is multilevel, providing commissions to distributors on their own sales as well as the sales of the distributors they recruit. At the time of the case, the company is grappling with a well-established change in consumer behavior—the decline of the stay-at-home mom as she returns to the workforce—combined with the opportunities offered by Internet selling. Focuses on the company's efforts to move with consumer demand and behavior, while remaining true to its core goal of “Improving Women's Lives.” Discusses ways Internet technology can be used throughout the company's channel and supply chain structure, not just as a route to market.
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