2,179 research outputs found

    A Stochastic Model of Plausibility in Live-Virtual-Constructive Environments

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    Distributed live-virtual-constructive simulation promises a number of benefits for the test and evaluation community, including reduced costs, access to simulations of limited availability assets, the ability to conduct large-scale multi-service test events, and recapitalization of existing simulation investments. However, geographically distributed systems are subject to fundamental state consistency limitations that make assessing the data quality of live-virtual-constructive experiments difficult. This research presents a data quality model based on the notion of plausible interaction outcomes. This model explicitly accounts for the lack of absolute state consistency in distributed real-time systems and offers system designers a means of estimating data quality and fitness for purpose. Experiments with World of Warcraft player trace data validate the plausibility model and exceedance probability estimates. Additional experiments with synthetic data illustrate the model\u27s use in ensuring fitness for purpose of live-virtual-constructive simulations and estimating the quality of data obtained from live-virtual-constructive experiments

    A Study on the Analyzing Priority of Limiting Factors in Live, Virtual, and Constructive (LVC) Simulation Interoperability Using Analytic Hierarchy Process (AHP) Method

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    Each Live, Virtual, and Constructive (LVC) simulation model has been developed and used with many benefits. When system developers created each simulation model, focused on specific standards to fit to their own respective purposes. Consequently, there have been interoperability issues among simulation models that have many limitations. To be specific, despite various efforts to achieve and maintain complete interoperability in LVC simulation environment, substantial limiting factors have remained in technical and managerial fields. Thus, analyzing and prioritizing limiting factors in LVC simulation is the effective way to solve interoperability problems while saving budget and time. The purpose of this research is to analyze the priority of limiting factors in LVC simulation interoperability. Based on the identified limiting factors from the literature review, this study performed Analytic Hierarchy Process (AHP) survey to generate weights of experts* judgement for each limiting factor. Following the AHP survey targeted to LVC simulation experts, this researcher suggest the priority of limiting factors that are needed to be focused on as well as recommendations for future research

    An Architectural Framework for Performance Analysis: Supporting the Design, Configuration, and Control of DIS /HLA Simulations

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    Technology advances are providing greater capabilities for most distributed computing environments. However, the advances in capabilities are paralleled by progressively increasing amounts of system complexity. In many instances, this complexity can lead to a lack of understanding regarding bottlenecks in run-time performance of distributed applications. This is especially true in the domain of distributed simulations where a myriad of enabling technologies are used as building blocks to provide large-scale, geographically disperse, dynamic virtual worlds. Persons responsible for the design, configuration, and control of distributed simulations need to understand the impact of decisions made regarding the allocation and use of the logical and physical resources that comprise a distributed simulation environment and how they effect run-time performance. Distributed Interactive Simulation (DIS) and High Level Architecture (HLA) simulation applications historically provide some of the most demanding distributed computing environments in terms of performance, and as such have a justified need for performance information sufficient to support decision-makers trying to improve system behavior. This research addresses two fundamental questions: (1) Is there an analysis framework suitable for characterizing DIS and HLA simulation performance? and (2) what kind of mechanism can be used to adequately monitor, measure, and collect performance data to support different performance analysis objectives for DIS and HLA simulations? This thesis presents a unified, architectural framework for DIS and HLA simulations, provides details on a performance monitoring system, and shows its effectiveness through a series of use cases that include practical applications of the framework to support real-world U.S. Department of Defense (DoD) programs. The thesis also discusses the robustness of the constructed framework and its applicability to performance analysis of more general distributed computing applications

    Uncertainty and Error in Combat Modeling, Simulation, and Analysis

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    Due to the infrequent and competitive nature of combat, several challenges present themselves when developing a predictive simulation. First, there is limited data with which to validate such analysis tools. Secondly, there are many aspects of combat modeling that are highly uncertain and not knowable. This research develops a comprehensive set of techniques for the treatment of uncertainty and error in combat modeling and simulation analysis. First, Evidence Theory is demonstrated as a framework for representing epistemic uncertainty in combat modeling output. Next, a novel method for sensitivity analysis of uncertainty in Evidence Theory is developed. This sensitivity analysis method generates marginal cumulative plausibility functions (CPFs) and cumulative belief functions (CBFs) and prioritizes the contribution of each factor by the Wasserstein distance (also known as the Kantorovich or Earth Movers distance) between the CBF and CPF. Using this method, a rank ordering of the simulation input factors can be produced with respect to uncertainty. Lastly, a procedure for prioritizing the impact of modeling choices on simulation output uncertainty in settings where multiple models are employed is developed. This analysis provides insight into the overall sensitivities of the system with respect to multiple modeling choices

    Applications of Virtual Reality

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    Information Technology is growing rapidly. With the birth of high-resolution graphics, high-speed computing and user interaction devices Virtual Reality has emerged as a major new technology in the mid 90es, last century. Virtual Reality technology is currently used in a broad range of applications. The best known are games, movies, simulations, therapy. From a manufacturing standpoint, there are some attractive applications including training, education, collaborative work and learning. This book provides an up-to-date discussion of the current research in Virtual Reality and its applications. It describes the current Virtual Reality state-of-the-art and points out many areas where there is still work to be done. We have chosen certain areas to cover in this book, which we believe will have potential significant impact on Virtual Reality and its applications. This book provides a definitive resource for wide variety of people including academicians, designers, developers, educators, engineers, practitioners, researchers, and graduate students

    Design of a Framework to Measure the Degree of Live Virtual Constructive (LVC) Simulation Interoperability

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    Accomplishment of the Live, Virtual and Constructive simulation interoperability has been a major goal and a challenge in the Modeling and Simulation (M&S) community. There have been efforts to interoperate individual Live, Virtual and Constructive simulations within a common synthetic environment through suitable technologies such as interface specifications, protocols, and standard middleware architectures. However, achieving interoperability of LVC simulation is a technologically complex since it is affected by multiple factors, and the characteristics are not yet satisfactorily defined and studied. A proper method is absent to measure the potential interoperability degree of LVC simulation. Therefore, there should be an appropriate systematic approach to measure the potential LVC simulation interoperability which includes technical, conceptual and organizational domains. This research aims to design a preliminary systematic approach to measure the potential interoperability degree of an individual Live, Virtual and Constructive simulation and a relevant organization which plans to use the simulation system for simulation interoperability. Specifically, a framework that contains components such as a) LVC simulation interoperability domains, b) interoperability domain factors, c) interoperability maturity levels, d) interoperability determination method is proposed. To accomplish the goal, a set of factors that determine the interoperability degree in LVC simulation environment are identified, and the factors are used to build the key elements of the framework. The proposed methodology for the framework design is based on systematic literature reviews and a survey involving a number of relevant domain experts. A case study is demonstrated to prove the validity and effectiveness of the developed framework. The case study illustrates how the interoperability levels of a simulation system and a relevant organization are effectively measured. This research potentially contributes by providing an understanding of the factors that determine the interoperability degree of LVC simulation, improvement of the LVC simulation interoperability measurement process, and consequently, accomplishment of more effective LVC simulation interoperability

    Technology standards and performance: the impact of social network service integration and open technology standards

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    For at least hundreds of years, if not longer, industries have been regularly transformed by the adoption of standards. Early examples from the early nineteenth century include the standardization of railroad track gauges and the introduction of interchangeable parts in the production of munitions. With the advent of the modern technology era, the introduction of standards has continued to transform industries that are now information technology driven. However, despite the broad consequences the introduction of standards presents, there remains a limited understanding of them. In this work we begin to build upon our understanding of the impact of standards by conducting a study on each of two distinct industries that have significant implications for society. The first industry considered is online services, focusing on an increasingly dominant subset that contains online communities. This industry is being transformed by the introduction of de facto standards for user profile management through social network service integration. The second industry studied is the defense avionics industry. This industry is positioned to potentially be transformed by the introduction of an open technology standard for software development. In the first study we investigate the impact of an increasingly common but understudied design option available to online communities: whether to integrate with a social network platform such as Facebook or Google+. Social network platform integration may provide several benefits to an online community, including creating more social interaction opportunities for members and helping members share personal information with each other to facilitate the creation of social bonds. Theory suggests that both of these factors (opportunities for interaction and disclosure of personal data) enhance the success of bond-based online communities, i.e., those in which member attachment to the community is driven by social bonds with other members. However, some elements of the theory have not been tested, and the theory does not consider the possibility that interaction opportunities and the disclosure of personal information might harm the online community by creating information privacy concerns among users. To address this gap, we tested the effect of implementing the “Login with Facebook” feature on new member registration and member social bond formation in an online virtual world community. Using a randomized field experiment as well as archival data analysis, we found that Facebook integration led to lower registration and lower social bond formation. I.e., it had a consistently negative effect on the online community. In addition to contributing to theory about the design of online communities, our results are also of practical interest to managers of online communities who have implemented or are planning to implement social network platform integration as well as to social network platforms who would like for their integration services to be more widely adopted. In the second study we examine the impact of introducing an open technology standard to the U.S. Defense Avionics industry. U.S. Defense Avionics is a multi-billion dollar industry featuring a monopoly buyer and pseudo-monopoly sellers, and its interplay of regulation and competition have traditionally favored secrecy and proprietary design as companies vie for huge multi-year contracts in a feast or famine market. Recognizing this, the U.S. government launched an initiative to develop an open technology standard jointly with industry, with the intention of using these standards to leverage the anticipated competition and efficiency benefits. Using a combination of interviews and a Delphi study, we examine the impact of this standard on software project effort across key industry firm archetypes. We find that experts anticipate a significant premium in the short term that transitions to cost reduction in the long term, with these expectations varying by firm type. This work contributes to the literature on open standards and learning by validating and quantifying the effect, and provides unique insights into U.S. Defense Avionics industry. This study also informs both expert and industry expectations as well as provides a best estimate of the actual impacts of adopting the standard.Ph.D

    Towards soundscape fingerprinting: development, analysis and assessment of underlying acoustic dimensions to describe acoustic environments

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    Soundscape according to the definition in ISO 12913-1 describes an acoustic environment as perceived by humans in context. In order to be able to assess a soundscape holistically, the components acoustic environment, person and context should be described sufficiently to enable triangulation. Person-based soundscape assessment has been the subject of extensive research over the past decades to date, leading to a good understanding of the main emotional dimensions. On the acoustic side, e.g., in modeling emotional responses by acoustic features, parameters describing loudness are widely used, also from the point of view of legal regulations. These parameters are often complemented by established psychoacoustic measures. However, it is unknown to what extent these parameters are suitable to adequately describe and compare acoustic environments for hypotheses concerning humans. The presented dissertation aims to contribute to this field by means of an exploratory, empirical, and data-based approach. First, the general requirements of the aim – the description of acoustic environments – are defined and accompanied with concepts and findings from current research areas. Subsequently a methodology is developed that allows for the identification of underlying acoustic dimensions on the basis of empirical observational data of real world acoustic environments by means of multivariate statistical methods. It contains considerations on the physical sound field, the human auditory system, as well as appropriate signal processing techniques. The methodology is then applied to an exemplary extensive dataset of various Ambisonics soundscape recordings. The resulting expressions of the acoustic dimensions are evaluated and discussed with respect to plausibility and perceptual consistency. Finally, two application examples are presented to further validate the methodology and to test the applicability of acoustic dimensions in concrete research scenarios. It was found that the presented methodology is suitable to identify dimensions for the description of acoustic environments. Furthermore, the dimensions found form a suitable basis for further soundscape analyses.Soundscape (nach ISO 12913-1) beschreibt eine akustische Umgebung, wie sie von Menschen im Kontext wahrgenommen wird. Eine ganzheitliche Beurteilung einer Soundscape wird demnach durch Triangulation der Aspekte akustische Umgebung, Person und Kontext hergestellt. Die personenbezogene Bewertung von Soundscapes war und ist bis heute Gegenstand umfangreicher Forschungsarbeiten, die zu einem weitreichendem Verständnis der wichtigsten emotionalen Dimensionen geführt haben. Auf der akustischen Seite sind Parameter weit verbreitet, die die Lautstärke beschreiben. Ergänzt werden diese Parameter oft durch etablierte psychoakustische Größen. Unbekannt ist jedoch, inwieweit diese (psycho-)akustischen Parameter tatsächlich geeignet sind, Soundscapes zu beschreiben und zu vergleichen hinsichtlich den Menschen betreffender Hypothesen. Hierzu soll diese Dissertation einen Beitrag leisten. Der dabei verfolgte Ansatz ist explorativ, empirisch und datenbasiert. Zunächst werden Anforderungen an das Ziel – die Beschreibung akustischer Umgebungen – definiert und mit Konzepten aus aktuellen Forschungsgebieten ergänzt. Anschließend wird eine Methodik entwickelt, die es erlaubt, fundamentale akustische Dimensionen zu identifizieren auf der Basis empirischer Beobachtungsdaten realer akustischer Umgebungen und mit Hilfe multivariater statistischer Methoden. Sie enthält Überlegungen zum physikalischen Schallfeld, zur menschlichen Hörwahrnehmung sowie zu geeigneten Signalverarbeitungstechniken. Die Methodik wird anschließend auf einen beispielhaften Datensatz von Ambisonics Soundscape-Aufnahmen angewandt. Die resultierenden akustischen Dimensionen werden hinsichtlich ihrer Plausibilität und wahrnehmungsbezogenen Konsistenz diskutiert. Schließlich werden zwei Anwendungsbeispiele vorgestellt, um die Methodik weiter zu validieren und um die Anwendbarkeit der akustischen Dimensionen in konkreten Forschungsszenarien zu testen. Hierbei kann festgestellt werden, dass die gefundenen Dimensionen einen hohen Grad an Varianz akustischer Umgebungen erklären können und gut interpretierbar sind. Sie bilden somit eine geeignete Grundlage für die hier dargestellte Analyse von Soundscapes. Die Methodik ist dabei variabel erweiterbar, sodass vielfältige Anwendungen und Forschungsarbeiten bzgl. akustischer Umgebungen ermöglicht werden

    INTEROPERABILITY FOR MODELING AND SIMULATION IN MARITIME EXTENDED FRAMEWORK

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    This thesis reports on the most relevant researches performed during the years of the Ph.D. at the Genova University and within the Simulation Team. The researches have been performed according to M&S well known recognized standards. The studies performed on interoperable simulation cover all the environments of the Extended Maritime Framework, namely Sea Surface, Underwater, Air, Coast & Land, Space and Cyber Space. The applications cover both the civil and defence domain. The aim is to demonstrate the potential of M&S applications for the Extended Maritime Framework, applied to innovative unmanned vehicles as well as to traditional assets, human personnel included. A variety of techniques and methodology have been fruitfully applied in the researches, ranging from interoperable simulation, discrete event simulation, stochastic simulation, artificial intelligence, decision support system and even human behaviour modelling
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