75 research outputs found
Charged fermions and strong cosmic censorship
No full textIt was recently shown that the Strong Cosmic Censorship conjecture might be violated for near-extremally-charged black holes in de Sitter space. Here, we extend our study to charged fermionic fields in the exterior of Reissner-Nordstrom-de Sitter black holes. We identify three families of modes; one related to the photon sphere, a second related to the de Sitter horizon and a third which dominates near extremality. We show that for near-extremally-charged black holes there is a critical fermionic charge below which Strong Cosmic Censorship may potentially be violated. Surprisingly enough, as one approaches extremality even more, violation of Strong Cosmic Censorship may occur even beyond the critical fermionic charge. (C) 2019 The Author. Published by Elsevier B.V
Despite Praise: Techniques of Paradoxology and Paradoxography in the Work of Kyriakos Charalambides
No full textCritics have often said that Kyriakos Charalambides’ poetry is hard and challenging even for the most cultivated and well-read reader. The author of the article examines the techniques of rhetoric style with which the poet orchestrates his inspirations: parentheses, stereotypical, corrective and introductory phrases, innuendoes, direct and indirect questions, comic scenes, etc.Critics have often said that Kyriakos Charalambides’ poetry is hard and challenging even for the most cultivated and well-read reader. The author of the article examines the techniques of rhetoric style with which the poet orchestrates his inspirations: parentheses, stereotypical, corrective and introductory phrases, innuendoes, direct and indirect questions, comic scenes, etc.À plusieurs reprises la critique a signalé que la poésie de Kyriakos Charalambidis présente beaucoup de résistances et des difficultés même pour les lecteurs les plus initiés. Dans cet article sont examinées des techniques rhétoriques de style à l’aide desquelles le poète orchestre ses inspirations poétiques: des parenthèses, des phrases stéréotypées, correctives, et annonciatrices, des sous-entendus, des questions directes et indirectes, des scènes comiques, etc
Kyriakos Mitsotakis: The Permanent Campaign Prime Minister
No full textThis chapter discusses the political background of Kyriakos Mitsotakis and evaluates his permanent campaigning at a time of the Covid-19 crisis and the resulting economic one. In particular, it examines his communication strategy from the perspective of the three categories of the permanent campaign indicators (capacity building and strategy, paid and owned media as well as earned media). It finds that Mitsotakis has so far applied permanent campaigning, to a greater degree, than any of his predecessors and thus can be considered as the ‘permanent campaign prime minister’. Moreover, he has put emphasis on all three sets of this communication strategy: capacity building and strategy, paid and owned media as well as earned media. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG
The sustainable growth paradigm : implications for technology and policy
No full textThesis (S.M. in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (leaves 102-109).While some scholars continue to insist that the concept of sustainability is vague and unwieldy, this thesis seeks to explore multidimensional elements of sustainability and seeks to offer an integrative, transdisciplinary approach to policy design for its attainment. Sustainability and the related concepts of development, globalization, and economic and environmental justice are interwoven with technological, social and institutional change, and with trade as drivers of the transformation of industrial and industrializing societies. The discussion begins by an analysis of the dominant existing models of economic growth and innovation and advances to the effects of economic growth on sustainability. Included is an analysis of the limits of the GDP growth paradigm, the effects of growth on the developed and the developing world and the relationship between economic growth and ecological collapse. The focus of analysis then shifts from the domestic to the international. Trade and the International Financial System are examined both with respect to their primary theories and characteristics, but also in relation to their effects to sustainability. The discussion is then concluded by an examination of the different policy options and analytical tools that could be employed for a transition to a more sustainable economic model.by Kyriakos Pierrakakis.S.M.in Technology and Polic
Semantic enrichment and exploration process on domain specific digital libraries
No full textWith the growing number of scientific publications, the conceptof navigating effectively and searching for domain specific informationis rather significant and highly important for the scientificcommunity [2]. For instance, to search by topics, research methods,used datasets, or scientific objectives. Such deep meta-data increaseour perception for a given domain (i.e. Data Processing Pipelines) andfacilitate us to understand and visualize the evolution of researchtopics and venues over time. Nevertheless, the extraction of suchdeep meta-data from text-based documents is notorious challengingand demanding due to the unstructured and ambiguous languageof the text in different publications.The work in this paper has already contributed into two publicationattempts; with one published paper at ESWC conference,and one accepted paper at the TPDL conference. Furthermore, thework in this project extends the analysis of previous attempts byadding more data from the domain of Data Processing Pipelines andby including one additional domain for analysis (i.e. the domainof Robotics). Moreover, this work provides justifications for all theimplementation decisions and proposes a refined version of theonline domain-aware semantic enrichment framework (SmartPub),that automates the generation of deep meta-data by utilizing keyfacets from the domains of Data Processing Pipelines and Robotics.The goal is to generate structured meta-data (i.e. named entities orphrases), from full-text scientific publications, with respect to a setof domain aware facets (i.e. Objective, Methods, Dataset, Software,and Results), and afterwards, to construct groups of facet-terms (i.e.facet-topics) according to their semantic similarity for allowingdata exploration and navigation. Finally, the proposed frameworkis evaluated both quantitatively and qualitatively on seventeen conferenceseries from the domains of Data Processing Pipelines andRobotics.<br/
Holistic Schema Matching at Scale
No full textSchema matching is a fundamental task in the data integration pipeline and has been studied extensively in the past decades, leading to many novel schema matching methods. However, these methods do not follow a standard evaluation process, leading to uncertainty in which one performs best in matching accuracy and runtime constraints, and in which specific schema matching category, and with what hyperparameters. To clear the confusion, the need for a scalable benchmarking suite to determine the field's progress became apparent, leading to the first contribution of this work, a scalable benchmarking suite for schema matching tasks. In the meantime, we realized that the literature lacked a scalable holistic schema matching system, leading to our second contribution. By considering the knowledge gained from our proposed benchmark, we developed a system that can incorporate any algorithm and data source while running the schema matching jobs in parallel across multiple machines in a scalable fashion. Furthermore, we decided to give a leading role to the users of such a system. The reason behind that is that it became apparent in the benchmark that no algorithm is perfect in every situation, and in mission-critical applications, we cannot afford any mistakes. Thus, the users would have to approve the proposed matches, and we focused on making this task scalable, fast, and straightforward.Computer Science | Software Technolog
Decentralized coordination for area surveillance purposes
No full textThe area surveillance problem is the problem of surveying a known or an unknown area with the main purpose of detecting objects. This thesis will tackle the problem of how to employ a group of mobile-sensors for surveying an unobstructed area in an optimal manner. The mobile-sensors should make use of their onboard computers and they should iteratively compute their waypoints until they successfully surveyed the area. To solve the area surveillance problem in an optimal manner, the mobile-sensors should be able to coordinate their actions. The Distributed Constraint Optimization Problem (DCOP) framework will be employed to define the area surveillance problem. In the DCOP, the mobile-sensors can define their optimal position for the next discrete time step by communicating with the other mobile-sensors that participate in the problem.For solving this DCOP, the Distributed Pseudo-tree Optimization Procedure (DPOP) will be utilized. The DPOP is a complete solver that can find the optimal solution of a DCOP in a decentralized manner. However, the main limitation of DPOP is that the size of the largest message that the mobile-sensors will have to exchange is space-exponential in the induced width of the pseudo-tree. Considering that the mobile-sensors have to use their onboard computers for solving the problem, exchanging huge size of messages is not desired. To overcome this limitation of DPOP, a new extension, known as the MST-DPOP will be presented in this Thesis. The MST-DPOP makes use of the Maximum Spanning Tree (MST) algorithm to reduce the size of the largest message that the mobile-sensors have to exchange. Employing MST along with DPOP can bound the size of the largest message and the required computations for constructing the utility messages. However, the new extension cannot guarantee that its solution will be the optimal. The experimental results shows that the MST-DPOP is able to define a solution with an average error less than . Moreover, the MST-DPOP requires on average around discrete time step more than the DPOP to solve the area surveillance problem. Consequently, given that the MST-DPOP overcomes the high memory requirements of DPOP, it is preferred for solving the area surveillance problem.Mechanical Engineering | Systems and Contro
Thermal and Electric Performance of PV/T Solar Chimney System
No full textThe residential and service sectors are responsible for the 39% of the total energy consumption. 80% of this energy is used for heating purposes. Achieving nearly zero energy buildings is a major goal for the near future. The design of an integrated electrical and thermal system can substantially help to reach such objective. The façade is the biggest area of a building and could be utilised to convert incident solar energy to electrical and thermal energy. In previous work (2019), the combination of building integrated PV modules with solar chimney on a façade was investigated to study its energetic performance. One of the main findings was that using the thermal energy from the photovoltaic modules on the air inside the cavity of the chimney is not possible due to its low quality of heat. It was concluded that the utilization of heat could be better by using auxiliary systems, like photovoltaic thermal systems for water heating. The aim of this work is to create a computational model to calculate the thermal and electrical performance of PV thermal (PV/T) modules combined with a solar chimney. Two new designs for better heat utilization where considered and compared. The first design is for the PV modules to be installed at the front of the solar chimney with fins (Fins design) and the second design is to couple the PV modules installed on the wall inside the solar chimney with water pipe system (Water pipe design). These designs are also compared with the same configurations but without the thermal systems (No fins & No water pipes designs). In addition, two new strategies are introduced to improve the performance of the model. The first strategy is the optimization of the solar chimney openings with respect of time for the highest power generation. The second strategy is the variation of the water mass flow with respect to time for highest water-thermal energy and optimum cooling of the PV cells. The model was developed in MATLAB and it is based on 2D finite difference transient implicit method. To reduce the computational time, the density of the nodes varies in respect of temperature gradient. In addition, secondary models were created to increase the accuracy and sensibility of the model such as water tank and water pump models. The models were studied for a building in Delft, Netherlands, and the scale of the chosen system is 10m2. It is concluded that Water pipes design provides the overall best energetic performance mainly because of the high water-thermal energy with yearly energy efficiency of 64.3%. However, the best electrical performance is observed from the Fins design and the best air-thermal performance from the No water pipes design.Electrical Engineering | Sustainable Energy Technolog
Best value procurement: Exploring its implementation for delivering beneficial project outputs across the market industry
No full textThe market industry is rapidly changing and modifications are taking place. Over the years, it has been noticed that project success is a challenging issue, which requires several endeavours from project parties. The procurement system is characterized as a tool, the implementation of which delivers project results. The procurement system is classified into four distinct categories; traditional, design & build, strategic & integrated, partnering. Based on those, the most popular procurement technique historically is the traditional method. The traditional method is mostly applied successfully in small projects, when less complexity and uncertainty emerge. However, the complexity and uncertainty have largely increased, marking the traditional method slightly impractical for successful results. In that case, a new procurement method is introduced, the Best Value Procurement (known as BVP) method. A critical advantage of the BVP is the embodiment of complexity and collaboration demands into its process. Despite its advantages and ambitions, the BVP does not always secure a successful result. Therefore, the main question that will be addressed in this research is: “How could public organizations implement Best Value Procurement (BVP) to benefit the project delivery?”To answer the main research question, a deep investigation through the BVP concept (elements, activities etc.) was executed. Firstly, an extensive literature review was exercised in order to cover the BVP method on the theoretical side. Based on the literature results, a theoretical BVP framework was established. Secondly, the findings acquired from the literature review were examined, leading to the exploratory interviews. Interviews are exploring the practical side of the BVP and how is applied in practice. Seven interviewees were selected. An understanding of differences and similarities between theory and practice was essential. Using the findings from the frameworks’ comparison, a list of adjustments (or recommendations) for improving the BVP method is established. Interviews with experts were held. Three experts, coming from public organisations and consultancy firms apply their knowledge and expertise in order to improve the BVP method. Thereafter, an alternative BVP framework was established. The alternative BVP framework incorporates components (elements, activities, including parties, final deliverables), the influence of which is characterized as critical for the BVP success. Public organisations frequently apply the BVP method in their projects. Being BVP initiators in the market industry, public organisations should implement BVP carefully. The alternative BVP framework, proposed in the research, could be used by public clients in order to achieve successful project outcomes. For a successful implementation of the BVP method, special attention should be attributed to the main alterations:General highlights:1. An introduction of Stage zero; training sessions, about BVP philosophy, are becoming availablethrough every single project participant2. An introduction of final deliverables (per step); setting clearly the deliverables to be received at the end of every stageSelection stage:1. Interviews inclusion as part of the evaluation process, not separate activity of the selection stage2. Consultants and tender managers are getting an important role throughout the selection stage3. Once the selection stage finishes, the evaluation committee or client has to select only one contractor. Multiple contractors should not be accepted...Civil Engineering | Construction Management and Engineerin
Challenges of Pharmacoeconomics in Global Health Arena
No full textThis eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contac
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