scholarly journals Comunicação, vigilância e infraestrutura: tecnopolíticas do espectro eletromagnético | Communication, surveillance and infrastructure: techno-politics of the electromagnetic spectrum

2016 ◽  
Vol 12 (2) ◽  
Author(s):  
Adriano Belisário ◽  
Paulo José O. M. Lara
Keyword(s):  
Radio Spectrum ◽  
Electromagnetic Spectrum ◽  
Political Dynamics ◽  
Free Spectrum ◽  
Communication Processes ◽  
Open Spectrum ◽  
Technological Model

RESUMO Este trabalho analisa algumas dinâmicas técnicas e políticas em torno dos usos e aplicações do espectro eletromagnético. Argumentando que a vigilância é parte intrínseca do desenvolvimento de certo modelo e arquitetura tecnológica em um nível infraestrutural, exploramos conceitos e práticas que buscam novas perspectivas de entendimento e ação dentro dessa camada essencial para os processos de comunicação que é o espectro. Iniciamos apresentando o espectro radioelétrico e seu gerenciamento para em seguida debater a noção de “espectro aberto” e seus usos mais recentes. Ao final, apresentamos exemplos que ilustram concepções alternativas técnicas e políticas por meio da noção de “espectro livre”.Palavras-Chave: Vigilância; Comunicação; Rádio; Espectro Eletromagnético; Tecnologia.ABSTRACT This paper examines technical and political dynamics around the uses and applications of the electromagnetic spectrum. Arguing that surveillance is an intrinsic part of the development of a certain technological model and architecture at an infrastructural level, we explore concepts and practices that seek new prospects for understanding and acting in this essential layer for communication processes that is the spectrum. We begin presenting the radio spectrum and its management to then discuss the notion of 'open spectrum' and its most recent uses. At the end, we present examples that illustrate alternative technical and political conceptions by means of the notion of a "free spectrum".Keywords: Surveillance; Communication; Radio, Electromagnetic Spectrum; Technology.

TRUST-BASED SPECTRUM SHARING FOR COGNITIVE RADIO NETWORKS

2011 ◽  
Vol 12 (03) ◽  
pp. 155-171 ◽  
Author(s):  
SAZIA PARVIN ◽  
FAROOKH KHADEER HUSSAIN ◽  
SONG HAN ◽  
OMAR KHADEER HUSSAIN
Keyword(s):  
Cognitive Radio ◽  
Cognitive Radio Networks ◽  
Spectrum Sharing ◽  
Stochastic Approach ◽  
Radio Spectrum ◽  
Spectrum Management ◽  
Radio Networks ◽  
Secondary Users ◽  
Reliable Technique ◽  
Free Spectrum

Cognitive Radio Networks (CRNs) is a promising technology which deals with shared spectrum access and usage in order to improve the utilization of limited radio spectrum resources for future wireless communications and mobile computing. Security becomes a very challenging issue in CRNs as different types of attacks are very common to cognitive radio technology compared to general wireless networks. The proper working of cognitive radio and the functionality of CRNs relies on the compliant behaviour of the secondary user. In order to address this issue, we propose two approaches in this paper. Firstly, we propose a trust aware model to authenticate the secondary users of CRNs which offers a reliable technique to provide a security-conscious decision by using trust evaluation for CRNs. Secondly, we propose an analytical model for analyzing the availability of spectrum in CRNs using a stochastic approach. We have modeled and analyzed the availability of free spectrum for the usage of secondary users by adopting different activities in a spectrum management scheme to improve the spectrum availability in CRNs.

scholarly journals The variable radio counterpart of Swift J1858.6-0814

2020 ◽  
Vol 496 (4) ◽  
pp. 4127-4140 ◽  
Author(s):  
J van den Eijnden ◽  
N Degenaar ◽  
T D Russell ◽  
D J K Buisson ◽  
D Altamirano ◽  
...  
Keyword(s):  
Time Scales ◽  
Radio Spectrum ◽  
Electromagnetic Spectrum ◽  
Very Large Array ◽  
X Ray ◽  
Geometric Origin ◽  
Optical Wavelengths ◽  
X Ray Binaries ◽  
Variable Radio

ABSTRACT Swift J1858.6-0814 is a transient neutron star X-ray binary discovered in 2018 October. Multiwavelength follow-up observations across the electromagnetic spectrum revealed many interesting properties, such as erratic flaring on minute time-scales and evidence for wind outflows at both X-ray and optical wavelengths, strong and variable local absorption, and an anomalously hard X-ray spectrum. Here, we report on a detailed radio observing campaign consisting of one observation at 5.5/9 GHz with the Australia Telescope Compact Array, and nine observations at 4.5/7.5 GHz with the Karl G. Jansky Very Large Array. A radio counterpart with a flat to inverted radio spectrum is detected in all observations, consistent with a compact jet being launched from the system. Swift J1858.6-0814 is highly variable at radio wavelengths in most observations, showing significant variability when imaged on 3-to-5-min time-scales and changing up to factors of 8 within 20 min. The periods of brightest radio emission are not associated with steep radio spectra, implying they do not originate from the launching of discrete ejecta. We find that the radio variability is similarly unlikely to have a geometric origin, be due to scintillation, or be causally related to the observed X-ray flaring. Instead, we find that it is consistent with being driven by variations in the accretion flow propagating down the compact jet. We compare the radio properties of SwiftJ1858.6-0814 with those of Eddington-limited X-ray binaries with similar X-ray and optical characteristics, but fail to find a match in radio variability, spectrum, and luminosity.

scholarly journals A REVIEW ON SPECTRUM SENSING METHODS FOR COGNITIVE RADIO NETWORKS

2016 ◽  
Vol 12 (18) ◽  
pp. 5053-5057
Author(s):  
K. Kaarthik ◽  
P.T. Sivagurunathan ◽  
S. Sivaranjani
Keyword(s):  
Cognitive Radio ◽  
Spectrum Sensing ◽  
Cognitive Radio Networks ◽  
Dynamic Spectrum Access ◽  
Cognitive Radios ◽  
Radio Spectrum ◽  
Radio Networks ◽  
Spectrum Access ◽  
Free Spectrum ◽  
Allocation Process

In Wireless Communication, Radio Spectrum is doing a vital role; for the future need it should use efficient. The existing system, it is not possible to use it efficiently where the allocation of spectrum is done based on fixed spectrum access (FSA) policy. Several surveys prove that it show the way to inefficient use of spectrum. An innovative technique is needed for spectrum utilization effectively. Using Dynamic spectrum access (DSA) policy, available spectrum can be exploited. Cognitive radio arises to be an attractive solution which introduces opportunistic usage of the frequency bands that are not commonly occupied by licensed users. Cognitive radios promote open spectrum allocation which is a clear departure from habitual command and control allocation process for radio spectrum usage. In short, it permits the formation of “infrastructure-less” joint network clusters which is called Cognitive Radio Networks (CRN). Conversely the spectrum sensing techniques are needed to detect free spectrum. In this paper, different spectrum sensing techniques are analyzed.

The Brunanburh Campaign: A Reappraisal

2005 ◽  
Vol 84 (2) ◽  
pp. 133-148 ◽  
Author(s):  
Kevin Halloran
Keyword(s):  
The Political ◽  
Variant Form ◽  
Political Dynamics ◽  
Battle Of Brunanburh

Modern accounts of the battle of Brunanburh have generally suggested a location in the Northumbrian-Mercian borderlands east or west of the Pennines, a conclusion based in part on analysis of the aims and strategy of Anlaf Guthfrithson, Viking king of Dublin. This article re-examines the political dynamics of the coalition against Athelstan, taking account of the territorial and political ambitions of the kings of Alba and Strathclyde, and proposes a radically different interpretation of the campaign of 937. It also questions the reliability of the variant form Brunanburh as a guide to the battle's location and concludes that the most likely site was Burnswark in Annandale.

Nationalism, Not Islam

2017 ◽  
Author(s):  
Faridullah Bezhan
Keyword(s):  
World War Ii ◽  
Political Party ◽  
Driving Forces ◽  
World War ◽  
Ruling Elite ◽  
Political Dynamics ◽  
Religious Establishment

Wish Zalmiyan or the ‘Awaken Youth Party’ (AYP) was the first political party to operate openly in Afghanistan. It enjoyed support from the intelligentsia and the monarchical regime. The AYP’s key ideological elements were nationalism and constitutionalism. While they made the party popular with a segment of the ruling elite and the intelligentsia, they brought resentment from the religious establishment for which Islam was the only ideology to be followed and the Quran the only constitution the country needed. This chapter examines how, in the aftermath of World War II, most members of the urban Afghan educated class leaned towards nationalism and constitutionalism as the driving forces for new political dynamics and the progress of the country. It explores what type of nationalism the Wish Zalmiyan party was advocating.

Transformation of education as a metatrend of the digital economy

2020 ◽  
Vol 16 (10) ◽  
pp. 1960-1979
Author(s):  
N.A. Egina ◽  
E.S. Zemskova
Keyword(s):  
Human Capital ◽  
Social Transformation ◽  
Network Effects ◽  
Digital Economy ◽  
Network Education ◽  
Economic Progress ◽  
Positive Externalities ◽  
Communication Processes ◽  
Education Network ◽  
The Impact

Subject. The study focuses on the impact of the digital economy determinants of the education transformation. Objectives. The article provides our own approach treating the education capital as a specific asset of the digital economy, which has an acceleration effect and sets up new trends in education through integrative networks. Methods. The study is based on principles of the systems integration, cross-disciplinary and multidisciplinary approaches. Results. The socio-economic progress was found to be determined with properties of human capital, which are solely specific to the digital economy. In new circumstances, it gets more important for actors of global, national, corporate and social networks to more actively cooperate within distributed networks in order to train high professionals, who would have skills in information networks. Thus, they would raise a new form of human capital – the capital of network education (network-based education capital). We describe positive externalities that arise when the educational sector joins communication processes. We illustrate how educational forms evolves, which are typical of a certain phase of the socio-economic development. The education capital was discovered to grow into a specific asset generating the quasi-rent and working as a social ladder only provided more actors are involved into the network. Conclusions and Relevance. Studying the evolution of educational forms through the cross-disciplinary method, we discovered the need for a system approach, which would help substantiate its transformation in the time of the digital economy, and the emergence of network-based education. These are technologies and tools of the digital economy that become unique factors generating the acceleration effect of the educational capital and ensuring the use of diverse network effects for the formation of intellectual capital and their social transformation.

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