565 research outputs found

    Cyber-Human Systems, Space Technologies, and Threats

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    CYBER-HUMAN SYSTEMS, SPACE TECHNOLOGIES, AND THREATS is our eighth textbook in a series covering the world of UASs / CUAS/ UUVs / SPACE. Other textbooks in our series are Space Systems Emerging Technologies and Operations; Drone Delivery of CBNRECy – DEW Weapons: Emerging Threats of Mini-Weapons of Mass Destruction and Disruption (WMDD); Disruptive Technologies with applications in Airline, Marine, Defense Industries; Unmanned Vehicle Systems & Operations On Air, Sea, Land; Counter Unmanned Aircraft Systems Technologies and Operations; Unmanned Aircraft Systems in the Cyber Domain: Protecting USA’s Advanced Air Assets, 2nd edition; and Unmanned Aircraft Systems (UAS) in the Cyber Domain Protecting USA’s Advanced Air Assets, 1st edition. Our previous seven titles have received considerable global recognition in the field. (Nichols & Carter, 2022) (Nichols, et al., 2021) (Nichols R. K., et al., 2020) (Nichols R. , et al., 2020) (Nichols R. , et al., 2019) (Nichols R. K., 2018) (Nichols R. K., et al., 2022)https://newprairiepress.org/ebooks/1052/thumbnail.jp

    I/Q Imbalance in Multiantenna Systems: Modeling, Analysis and RF-Aware Digital Beamforming

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    Wireless communications has experienced an unprecedented increase in data rates, numbers of active devices and selection of applications during recent years. However, this is expected to be just a start for future developments where a wireless connection is seen as a fundamental resource for almost any electrical device, no matter where and when it is operating. Since current radio technologies cannot provide such services with reasonable costs or even at all, a multitude of technological developments will be needed. One of the most important subjects, in addition to higher bandwidths and flexible network functionalities, is the exploitation of multiple antennas in base stations (BSs) as well as in user equipment (UEs). That kind of multiantenna communications can boost the capacity of an individual UE-BS link through spatial antenna multiplexing and increase the quality as well as robustness of the link via antenna diversity. Multiantenna technologies provide improvements also on the network level through spatial UE multiplexing and sophisticated interference management. Additionally, multiple antennas can provide savings in terms of the dissipated power since transmission and reception can be steered more efficiently in space, and thus power leakage to other directions is decreased. However, several issues need to be considered in order to get multiantenna technologies widely spread. First, antennas and the associated transceiver chains are required to be simple and implementable with low costs. Second, size of the antennas and transceivers need to be minimized. Finally, power consumption of the system must be kept under control. The importance of these requirements is even emphasized when considering massive multiple-input multiple-output (MIMO) systems consisting of devices equipped with tens or even hundreds of antennas.In this thesis, we consider multiantenna devices where the associated transceiver chains are implemented in such a way that the requirements above can be met. In particular, we focus on the direct-conversion transceiver principle which is seen as a promising radio architecture for multiantenna systems due to its low costs, small size, low power consumption and good flexibility. Whereas these aspects are very promising, direct-conversion transceivers have also some disadvantages and are vulnerable to certain imperfections in the analog radio frequency (RF) electronics in particular. Since the effects of these imperfections usually get even worse when optimizing costs of the devices, the scope of the thesis is on the effects and mitigation of one of the most severe RF imperfection, namely in-phase/quadrature (I/Q) imbalance.Contributions of the thesis can be split into two main themes. First of them is multiantenna narrowband beamforming under transmitter (TX) and receiver (RX) I/Q imbalances. We start by creating a model for the signals at the TX and RX, both under I/Q imbalances. Based on these models we derive analytical expressions for the antenna array radiation patterns and notice that I/Q imbalance distorts not only the signals but also the radiation characteristics of the array. After that, stemming from the nature of the distortion, we utilize widely-linear (WL) processing, where the signals and their complex conjugates are processed jointly, for the beamforming task under I/Q imbalance. Such WL processing with different kind of statistical and adaptive beamforming algorithms is finally shown to provide a flexible operation as well as distortion-free signals and radiation patterns when being under various I/Q imbalance schemes.The second theme extends the work to wideband systems utilizing orthogonal frequency-division multiplexing (OFDM)-based waveforms. The focus is on uplink communications and BS RX processing in a multiuser MIMO (MU-MIMO) scheme where spatial UE multiplexing is applied and further UE multiplexing takes place in frequency domain through the orthogonal frequency-division multiple access (OFDMA) principle. Moreover, we include the effects of external co-channel interference into our analysis in order to model the challenges in heterogeneous networks. We formulate a flexible signal model for a generic uplink scheme where I/Q imbalance occurs on both TX and RX sides. Based on the model, we analyze the signal distortion in frequency domain and develop augmented RX processing methods which process signals at mirror subcarrier pairs jointly. Additionally, the proposed augmented methods are numerically shown to outperform corresponding per-subcarrier method in terms of the instantaneous signal-to-interference-and-noise ratio (SINR). Finally, we address some practical aspects and conclude that the augmented processing principle is a promising tool for RX processing in multiantenna wideband systems under I/Q imbalance.The thesis provides important insight for development of future radio networks. In particular, the results can be used as such for implementing digital signal processing (DSP)-based RF impairment mitigation in real world transceivers. Moreover, the results can be used as a starting point for future research concerning, e.g., joint effects of multiple RF impairments and their mitigation in multiantenna systems. Overall, this thesis and the associated publications can help the communications society to reach the ambitious aim of flexible, low-cost and high performance radio networks in the future

    2009, UMaine News Press Releases

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    This is a catalog of press releases put out by the University of Maine Division of Marketing and Communications between January 2, 2009 and December 30, 2009

    Necessitation through Growing Entanglements: Why We “Can’t Live Without” Some Products

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    Much research has been concerned with what constitute necessities and how they are related to pertinent concepts, such as needs, wants, desires, and luxuries (Belk, Ger, and Askegaard 2003; Duncan 2002; Fraser 1998, Hoyer and MacInnis 2004; Kerin, Hartley and Rudelius 2004; Sheth and Mittal 2004). Using thing-focused approaches, earlier studies are primarily concerned with classification schemes using dichotomies such as need-want and necessity-luxury. Studies that employ a human-focused perspective challenge these divisions and argue that necessities cannot be studied without considering the social and historical contexts (e.g., Buttle 1989; Firat 1987). Notwithstanding the important contributions that these studies have made, they have often explored necessities and necessitation primarily from the perspective of a dominant human subject (i.e., the consumer), where things (i.e., products) primarily serve as vehicles for consumer meaning. The contribution of this research is two-fold. First, a macro narrative that identifies five stages of smartphone necessitation in news consumption is derived from a narrative analysis of consumer texts, in order to better understand how consumers experience product necessitation. These stages are familiarization, transformation, memorialization, (re)integration and reconstruction, and solidification. Necessitation is achieved when consumers come to feel that they cannot live without this product. Second, entanglement theory (Hodder 2012) with its accentuation of dependences is employed. Hodder (2012) argues against the symmetrical nature of relations, suggesting that they are often asymmetrical. This observation translates into the concept of entanglement, which is “the dialectic of dependence and dependency between humans and things” (Hodder 2012, p. 89). Dependence occurs when the use of things is something enabling, while dependency is to be understood as occurring when their use imposes a constraint on humans (Hodder 2012).Tracing the historical increase of entanglements of news consumption leading to the necessitation of the smartphone, this study finds that necessitation emerges as a result of numerous small changes within entanglements over time, which, in turn, produce unexpected problems that need fixing. The solutions further increase entanglements and lead humans and things down the pathway of product necessitation. As the affordances of a product are gradually exploited, they fully entangle with a wide range of humans and things. Eventually a level of entanglements is reached that makes it difficult and expensive to turn back or disentangle, making the product come to be near-universally perceived as necessary

    Management: A bibliography for NASA managers

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    This bibliography lists 630 reports, articles and other documents introduced into the NASA Scientific and Technical Information System in 1991. Items are selected and grouped according to their usefulness to the manager as manager. Citations are grouped into ten subject categories: human factors and personnel issues; management theory and techniques; industrial management and manufacturing; robotics and expert systems; computers and information management; research and development; economics, costs and markets; logistics and operations management; reliability and quality control; and legality, legislation, and policy

    Advanced Trends in Wireless Communications

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    Physical limitations on wireless communication channels impose huge challenges to reliable communication. Bandwidth limitations, propagation loss, noise and interference make the wireless channel a narrow pipe that does not readily accommodate rapid flow of data. Thus, researches aim to design systems that are suitable to operate in such channels, in order to have high performance quality of service. Also, the mobility of the communication systems requires further investigations to reduce the complexity and the power consumption of the receiver. This book aims to provide highlights of the current research in the field of wireless communications. The subjects discussed are very valuable to communication researchers rather than researchers in the wireless related areas. The book chapters cover a wide range of wireless communication topics

    Digital Research Cycles: How Attitudes Toward Content, Culture And Technology Affect Web Development.

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    It has been estimated that one third of the world\u27s population does not have access to adequate health care. Some 1.6 billion people live in countries experiencing concentrated acquired immune deficiency syndrome (AIDS) epidemics. Many countries in Africa--and other low-income countries--are in dire need of help providing adequate health care services to their citizens. They require more hands-on care from Western health workers--and training so more African health workers can eventually care for their own citizens. But these countries also need assistance acquiring and implementing both texts--the body of medical information potentially available to them--and technology--the means by which that information can be conveyed. This dissertation looks at these issues and others from a multi-faceted approach. It combines a survey of the developers of Web sites designed for use by health workers in low-income countries and a proposal for a novel approach to communication theory, which could help improve health communication and other social marketing practices. It also includes an extensive review of literature regarding a number of topics related to these issues. To improve healthcare services in low-income countries, several things should occur. First, more health workers--and others--could visit African countries and other places to provide free, hands-on medical care, as this researcher\u27s group did in Uganda. Such trips are ideal occasions for studying the cultural differences between mzungu (white man) and the Ugandan people. A number of useful medical texts have been written for health workers in low-income countries. Others will be published as new health information becomes available. But on what medium will they be published? Computers? Personal digital assistants? During the past 10 years the Internet became an ideal venue for conveying information. Unfortunately, people in target countries such as Uganda encounter cultural differences when such new technologies are diffused. This dissertation looks at cultural and technological difficulties encountered by people in low-income countries who attempt to diffuse information and communication technologies (ICT). Once a technology has been successfully adopted, someone will look for ways to use it to help others. There are hundreds of sites on the Internet--built by Web developers in Western countries--that are designed for use by health workers in low-income countries. However, these Web developers also experience cultural and technological differences, based on their knowledge of and attitudes toward best practices in their field. This research includes a survey of Web developers which determined their attitudes toward best practices in their field and tested this researcher\u27s hypothesis that there is no significant difference among the developers\u27 attitudes toward the content on their sites, their audience\u27s cultural needs and the various technological needs their audience has. It was found that the Web developers agree with 17 of 18 perceived best practices and that there is a significant difference between Web developers\u27 attitudes toward their audience\u27s technological needs and their attitudes toward quality content and the audience\u27s cultural needs. Creation of the survey herein resulted in this researcher generating a new way of thinking about communication theory--called digital research cycles. The survey was based on a review of literature and is rooted in the belief that any successful communication of a computer-mediated message in the information age is a behavior which is influenced by the senders\u27 and receivers\u27 attitudes and knowledge about textual style, the audience, technology and the subject matter to which the message pertains

    mHealth in Practice

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    This book is available as open access through the Bloomsbury Open Access programme and is available on www.bloomsburycollections.com. There has recently been an explosion of interest around the application of mobile communication technologies to support health initiatives in developing countries (mHealth). As a result, there is a need to promote and share rigorous research for better informed policy, programming, and investment. There are, however, few platforms for the exchange of information and proven practice between practitioners and researchers. The subtopic of prevention, well-being, and health promotion within mHealth is particularly ripe for deeper exploration. While many reports tout the potential of mobiles to influence behaviour change for health, there is limited knowledge about what works (and what does not work), and about how to evaluate current and future programs. This is a focused edited volume with contributions from leading researchers and practitioners to identify best practices in using mobile technologies to promote healthy behaviours (and reduce unhealthy ones) in resource-constrained settings with a special focus on developing countries. This topic is inherently interdisciplinary. Though the opportunities to leverage mobile phones for health are new, the challenges confronting researchers and practitioners are well-established and theoretically complex, with roots in decades of work on mediated behaviour change campaigns and theories

    Beyond Your Perception: An Exploratory Study of Black Parent-Daughter Relationships and Hip Hop Influences on Adolescent Girls

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    ABSTRACT BEYOND YOUR PERCEPTION: AN EXPLORATORY STUDY OF BLACK PARENT-DAUGHTER RELATIONSHIPS AND HIP HOP INFLUENCES ON ADOLESCENT GIRLS by Sherell A. McArthur This study is situated at the nexus of three bodies of literature and research and sought to contribute to all three: the socialization of Black girls, hip hop as a pedagogical tool and critical media literacy. My research explored how might the Black parent-daughter relationship serve as a vehicle by which the girls come to understand, submit to, and/or resist the stereotypical images prevalent in the hip-hop culture? I co-created a critical media literacy collective with high school, African American girls where we explored personal identity development in relationship to representations of African-American women in the media. It was through my interactions with the girls in this collective, named Beyond Your Perception (BYP). Through this collective, the primary data sources were qualitative interviews, focus groups, and documents. A thematic analysis revealed Black girls represent the dominant narratives within the cultural movement of hip hop by ascribing to cultural mores like fashion trends, hairstyles and language. They also consciously choose to resist the stereotypical imagery (e.g., loud, angry, sexually loose, etc.) and are able to compose powerful counter-narratives to the monolithic depictions of Black women in the media. By examining the data it was evident that parents engage with hip hop media by listening to the music and watching television shows and music videos, however the ways in which they engage their daughters in dialogue pertaining to the messages within hip hop media is sporadic and suggests the need for parents to become media literate. The implications of this study suggest the need for the creation of collaborative and emancipatory spaces for Black girls, media literacy education for parents, and culturally relevant pedagogy

    Perceptual fail: Female power, mobile technologies and images of self

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    Like a biological species, images of self have descended and modified throughout their journey down the ages, interweaving and recharging their viability with the necessary interjections from culture, tools and technology. Part of this journey has seen images of self also become an intrinsic function within the narratives about female power; consider Helen of Troy “a face that launched a thousand ships” (Marlowe, 1604) or Kim Kardashian (KUWTK) who heralded in the mass mediated ‘selfie’ as a social practice. The interweaving process itself sees the image oscillate between naturalized ‘icon’ and idealized ‘symbol’ of what the person looked like and/or aspired to become. These public images can confirm or constitute beauty ideals as well as influence (via imitation) behaviour and mannerisms, and as such the viewers belief in the veracity of the representative image also becomes intrinsically political manipulating the associated narratives and fostering prejudice (Dobson 2015, Korsmeyer 2004, Pollock 2003). The selfie is arguably ‘a sui generis,’ whilst it is a mediated photographic image of self, it contains its own codes of communication and decorum that fostered the formation of numerous new digital communities and influenced new media aesthetics . For example the selfie is both of nature (it is still a time based piece of documentation) and known to be perceptually untrue (filtered, modified and full of artifice). The paper will seek to demonstrate how selfie culture is infused both by considerable levels of perceptual failings that are now central to contemporary celebrity culture and its’ notion of glamour which in turn is intrinsically linked (but not solely defined) by the province of feminine desire for reinvention, transformation or “self-sexualisation” (Hall, West and McIntyre, 2012). The subject, like the Kardashians or selfies, is divisive. In conclusion this paper will explore the paradox of the perceptual failings at play within selfie culture more broadly, like ‘Reality TV’ selfies are infamously fake yet seem to provide Debord’s (1967) illusory cultural opiate whilst fulfilling a cultural longing. Questions then emerge when considering the narrative impact of these trends on engendered power structures and the traditional status of illusion and narrative fiction
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