Mixed Prototyping Research Articles

OVERCOMING AUGMENTED REALITY ADOPTION BARRIERS IN DESIGN: A MIXED PROTOTYPING CONTENT AUTHORING TOOL SUPPORTED BY COMPUTER VISION

AbstractEnhancing the appearance of physical prototypes with digital elements, also known as mixed prototyping, has demonstrated to be a valuable approach in the product development process. However, the adoption is limited also due to the high time and competence required for authoring the digital contents. This paper presents a content authoring tool that aims to improve the user acceptance by reducing the specific competence required, which is needed for segmentation and UV mapping of the 3D model used to implement a mixed prototype. Part of the tasks related to 3D modelling software, in fact, has been transferred to simpler manual tasks applied onto the physical prototype. Moreover, the proposed tool can recognise these manual inputs thanks to a computer-vision algorithm and automatically manage the segmentation and UV mapping tasks, freeing time for the user in a task that otherwise would require complete engagement. To preliminarily evaluate effectiveness and potential of the tool, it has been used in a case study to build up the mixed prototype of a coffee machine. The result demonstrated that the tool can correctly segment the 3D model of a physical prototype in its relevant parts and generate their corresponding UV maps.

A Framework to Assess Human Performance in Normal and Emergency Situations

Abstract Human error is one of the primary reasons for accidents in complex industries like aviation, nuclear power plant management, and health care. Physical and cognitive workload, flawed information processing, and poor decision making are some of the reasons that make humans vulnerable to error and lead to failures and accidents. In many accidents and failures, oftentimes, vulnerabilities that are embedded in the system, in the form of design deficiencies and poor human factors, lead to latent or catastrophic failures, but the last link is a human operator who gets blamed or worse, injured. This paper introduces an early design human performance assessment framework to identify what type of digital prototyping methodologies are appropriate to detect the deviation of the operator's performance due to an emergency condition. Fire in a civilian aircraft cockpit was introduced as a performance shaping factor (PSF). Ergonomics performance was evaluated using two prototyping strategies: (1) a computational prototyping framework includes digital human modeling (DHM) and computer-aided design; and (2) a novel mixed prototyping framework includes motion capture, DHM, and virtual reality. Results showed that the mixed prototyping framework can simulate emergency scenarios with increased realism and also has the potential to incorporate subjective aspects of ergonomics outcomes, overcoming the underlying lack of design knowledge in conventional early design methodologies.

Determining fidelity of mixed prototypes: Effect of media and physical interaction

Mixed prototyping, combining virtual and physical prototypes, is an emerging method used to aid in usability testing. This study aims to determine when to use a mixed prototype and how to choose its fidelity to validate the usability testing results and reduce the prototyping cost. A 2×2 between-subject experiment was designed to investigate the effects of the media (head-mounted display versus computer monitor) and physical interaction (using a tangible mock-up or not) on the usability evaluation results and other subjective measures. The experiment results showed that, when aesthetic and functional features are controlled, the non-functional mock-up facilitates users in finding problems regarding physical interaction and ergonomics. Media with high immersion positively influenced the users’ subjective ratings. Based on the findings of this study, guidelines on how to choose the fidelity of the prototype during different stages of a usability test are suggested to help product developers find a cost-efficient way to conduct usability tests.

Mixed prototypes for the evaluation of usability and user experience: simulating an interactive electronic device

Mixed prototyping technology can be used to represent and simulate the behavior of interactive products at low cost and with great flexibility. This preliminary experimental research intends to verify the suitability of using this technology in the evaluation of usability and user experience of interactive products. Users and experts evaluate the mixed prototype of an image projector with regard to its own usability, and also with respect to its ability to be used to evaluate usability and user experience aspects of the real projector. Users perform tasks on both the real projector and its mixed prototype. In regard to these comparative performance evaluations, time to perform the task and number of errors show a clear positive relationship with the difficulty of the task for both mixed prototype and real projector. In regard to more subjective UX evaluations, the results show to be congruent. However, we realize that emotions assigned to the mixed prototype are influenced by the “fascination” that augmented reality arises in individuals. Experts evaluate the mixed prototype with respect to aspects of the interaction with the product that it is able to simulate, and with respect to the classes of products best suited to be prototyped. They highlighted the possibility of using the technology to evaluate product performance, ergonomics, and operation. In regard to the classes of products to be prototyped, experts’ suggestions coincided with the classes of products that have already been used in research: household appliances, information and communication devices, and automotive parts and accessories.

A mixed reality tool for end-users participation in early creative design tasks

While mixed prototyping has proved to be effective for the assessment of prototypes, this research aims to explore the use of mixed prototyping for the generation of early prototypes. To satisfy end-user’s needs, new products need to be designed with an early integration of end-user requirements. An efficient way to achieve this is to directly integrate the end-users in the design process and give them an intelligible and interactive tool to perform specific design tasks. Current interactive tools to integrate end-users in the design process provide either a high level of immersion (e.g. CAVE) or a high level of control over the virtual prototype (e.g. configurators). We designed a new mixed reality design tool which simultaneously allows end-users to be immersed in a virtual environment (immersion) and to interact with a virtual prototype and to modify it (control), resulting in effective end user-interactions. In two design use-case scenarios, we assessed the end-user experience and satisfaction while using the tool and we also evaluated the impact of the tool on the creative process and the design outcomes. The findings show that, when users are provided with a tool that allows to directly perform design tasks and modify a virtual prototype, as compared to when they have no control, they are more engaged in the design tasks, more satisfied with the design process and they produce more creative outcomes.

Mixed prototyping with configurable physical archetype for usability evaluation of product interfaces

Mixed prototyping (MP) is an emerging approach for usability testing, thanks to its multimodal environment, which is able to involve sight, hearing and touch thus improving the ability to analyze the inter-relationships between the physical form and the behavior of the industrial products.This paper presents a method to perform usability tests in a mixed reality (MR) environment for analyzing human performance in target acquisition tasks while interacting with household appliances. The proposed method is based on the use of different kinds of digital and physical prototypes and, moreover, it introduces an experimental physical archetype for mixed prototyping that contributes to increase the efficiency of the usability evaluation process. Through this archetype the design of a user interface can be easily changed by the adoption of plug-and-play moving components (knobs and buttons) that allow to model in a few seconds any kind of control panel for washing machines, thus reducing the prototyping costs and enlarging the variety of MR interfaces that can be evaluated.The paper proposes also a validation of the use of the physical archetype through a case study in which three different control panel alternatives have been evaluated in a competitive usability study. The competitive testing allows to gather user behaviors with a broad range of design options before the development of a new control panel refined through iterative design.Experimental results show that the proposed method based on the physical archetype can be an effective support to improve the usability of the product interface.

Mixed prototyping for product assessment: a reference framework

The paper presents a reference framework for applications based on the mixed prototyping practice and mixed reality techniques and technologies. This practice can be effectively used for rapid design assessment of new products. In particular, the paper addresses applications regarding the use of mixed prototyping practice for the design review of information appliances. Various methods and technologies can be used according to the product aspects to validate and test. The paper describes mixed prototyping applications for positioning information appliances within systems and for the evaluation of ergonomics aspects of interactive devices.

Design and development of a mixed signal prototyping system to achieve very high data rates for contactless applications

Contactless applications like ePassport (electronic passport) demand increased communication speed for higher volumes of exchanged data. Today, those passive applications are working at the carrier frequency of 13.56 MHz, as standardized in ISO/IEC 14443, including data rates up to 848 kbps. However, higher data rates are currently a field of research. For the investigation of very high data rates a mixed signal prototyping system is introduced, based on a new concept of a FPGA-based reader prototyping system. Moreover, an introduction to advanced demodulation methods for contactless transponder devices is given.

A MC-CDMA system analysis in a software radio context

This paper presents a Multi-Carrier Code Division Multiple Access (Mc-Cdma) system analysis in a software radio context. Based on a combination of multi-carrier modulation and code division multiple access,Mc-Cdma benefits from the main advantages from both schemes: high spectral efficiency, high flexibility, multiple access capabilities, etc. It is firstly shown why, nowadays,Mc-Cdma is undoubtedly a high potential candidate for the air interface of the 4G cellular networks. TheMc-Cdma concept and the block-diagrams of the transmitter and the receiver are presented first. Afterwards, the technical issues concerning the processing devices for the implementation ofMc-Cdma systems in a software radio context are analysed. The advantages and disadvantages of Digital Signal Processors (Dsps) and Field Programmable Gate Arrays (Fgpas) components are discussed. The implementation ofMc-Cdma systems and the integration of signal processing algorithms as Fast Hadamard Transform (Fht) and Inverse Fast Fourier Transform (Ifft) are considered and analysed for the first time. Finally, implementation results with a mixed prototyping board are presented. Then, it is shown that a new combination of the flow graphs ofFht andIfft leads to interesting computation savings and that hardware structures asFgpas are more adapted thanDsps to those intensive computation functions. Finally, for the completeMc-Cdma modem implementation, the necessity of a Co-Design methodology is highlighted in order to obtain the best matching between algorithms and architecture.

Interactive evaluation of assembly sequences using augmented reality

This paper describes an interactive tool for evaluating assembly sequences using the novel human-computer interface of augmented reality. The goal is to be able to consider various sequencing alternatives of the manufacturing design process by manipulating both virtual and real prototype components. The augmented reality-based assembly evaluation tool would allow a manufacturing engineer to interact with the assembly planner while manipulating the real and virtual prototype components in an assembly environment. Information from the assembly planner can be displayed directly superimposed on the real. A sensing technique is proposed that uses computer vision along with a system of markers for automatically monitoring the assembly state as the user manipulates the assembly components. An implemented system called AREAS is described. The advantage of using mixed prototyping and augmented reality as means of capturing human intuition in assembly planning is also discussed.