774 research outputs found

    Modern computing: Vision and challenges

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    Over the past six decades, the computing systems field has experienced significant transformations, profoundly impacting society with transformational developments, such as the Internet and the commodification of computing. Underpinned by technological advancements, computer systems, far from being static, have been continuously evolving and adapting to cover multifaceted societal niches. This has led to new paradigms such as cloud, fog, edge computing, and the Internet of Things (IoT), which offer fresh economic and creative opportunities. Nevertheless, this rapid change poses complex research challenges, especially in maximizing potential and enhancing functionality. As such, to maintain an economical level of performance that meets ever-tighter requirements, one must understand the drivers of new model emergence and expansion, and how contemporary challenges differ from past ones. To that end, this article investigates and assesses the factors influencing the evolution of computing systems, covering established systems and architectures as well as newer developments, such as serverless computing, quantum computing, and on-device AI on edge devices. Trends emerge when one traces technological trajectory, which includes the rapid obsolescence of frameworks due to business and technical constraints, a move towards specialized systems and models, and varying approaches to centralized and decentralized control. This comprehensive review of modern computing systems looks ahead to the future of research in the field, highlighting key challenges and emerging trends, and underscoring their importance in cost-effectively driving technological progress

    Beam scanning by liquid-crystal biasing in a modified SIW structure

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    A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium

    Tradition and Innovation in Construction Project Management

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    This book is a reprint of the Special Issue 'Tradition and Innovation in Construction Project Management' that was published in the journal Buildings

    National security exceptions: a shield or a weapon?:Balancing States’ autonomy to adopt security measures and International Economic Law

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    For nearly seventy years, countries did an excellent job of protecting the multilateral trading system from deciding whether national security was a legitimate defense for any given country’s measures, whether it was a trade ban, sanctions, or export restrictions. Then, in 2017 and 2018, several panels of the World Trade Organization (WTO) were established after respondents declared that they considered the challenged measures necessary to protect their essential security interests. Notably, these disputes started to mushroom when national security rhetoric gained prominence, partly due to emerging concerns raised by cybersecurity, geo-economic rivalry, technological nationalism, climate change, supply chain crisis, and migration flows. Such concerns have provoked reforms and strategic policies. Yet, by attempting to restore their sense of security, states have actually enlarged insecurity in the global economy, for example, by claiming that security exceptions can allow anything under the sun. The question that this dissertation tackles is how countries can restore the balance between states’ autonomy to protect national security and binding international law, taking into account new economic and political realities. This dissertation argues that existing security exceptions are either drafted too broadly, making it difficult to control their good faith application and creating verification problems for international courts, or too narrowly, arguably excluding from their scope the protection against insidious, imminent, yet severe emerging security threats. There is a risk that both approaches might undermine the balance between states’ sovereignty and international economic law by unjustifiably limiting the ability of states to take efficient security actions or opening the door to protectionism or opportunism by allowing any measure that a state considers necessary. Unlike other proposals, this dissertation starts from the premise that countries will be given the most space for dialogue if they admit that some national security questions are more prone to stricter regulation than others. To this end, this dissertation suggests states renegotiate existing security exceptions and change the approach to drafting them in future agreements. This dissertation synthesizes the existing doctrinal and empirical work on the application of security exceptions under international trade and investment law but also turns to the case studies of the United States, the European Union, and BRICS countries (Brazil, Russia, India, China, and South Africa) – by virtue of the economic and political power of such WTO members, their importance in global supply chains, and their roles in the transformation of the global order. It aims to expand the rulebook on the application of security exceptions, improve cooperation between the WTO and the United Nations, and incentivize states to use trade and investment restrictions more efficiently, thereby permitting more policy space for calibrated responses to new externalities while reinforcing the function of security exceptions to shield states from responsibility only in extreme situations. The interdisciplinary constituency of such research affects the normative understanding of security exceptions and enables the discussion over the practice of application of security measures from different analytical lenses, making this research interesting for practitioners, academics, and policymakers dealing with the intersection between international economic law and national security

    1-D broadside-radiating leaky-wave antenna based on a numerically synthesized impedance surface

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    A newly-developed deterministic numerical technique for the automated design of metasurface antennas is applied here for the first time to the design of a 1-D printed Leaky-Wave Antenna (LWA) for broadside radiation. The surface impedance synthesis process does not require any a priori knowledge on the impedance pattern, and starts from a mask constraint on the desired far-field and practical bounds on the unit cell impedance values. The designed reactance surface for broadside radiation exhibits a non conventional patterning; this highlights the merit of using an automated design process for a design well known to be challenging for analytical methods. The antenna is physically implemented with an array of metal strips with varying gap widths and simulation results show very good agreement with the predicted performance

    METROPOLITAN ENCHANTMENT AND DISENCHANTMENT. METROPOLITAN ANTHROPOLOGY FOR THE CONTEMPORARY LIVING MAP CONSTRUCTION

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    We can no longer interpret the contemporary metropolis as we did in the last century. The thought of civil economy regarding the contemporary Metropolis conflicts more or less radically with the merely acquisitive dimension of the behaviour of its citizens. What is needed is therefore a new capacity for imagining the economic-productive future of the city: hybrid social enterprises, economically sustainable, structured and capable of using technologies, could be a solution for producing value and distributing it fairly and inclusively. Metropolitan Urbanity is another issue to establish. Metropolis needs new spaces where inclusion can occur, and where a repository of the imagery can be recreated. What is the ontology behind the technique of metropolitan planning and management, its vision and its symbols? Competitiveness, speed, and meritocracy are political words, not technical ones. Metropolitan Urbanity is the characteristic of a polis that expresses itself in its public places. Today, however, public places are private ones that are destined for public use. The Common Good has always had a space of representation in the city, which was the public space. Today, the Green-Grey Infrastructure is the metropolitan city's monument that communicates a value for future generations and must therefore be recognised and imagined; it is the production of the metropolitan symbolic imagery, the new magic of the city
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