3,516 research outputs found
Wireless network virtualization: Opportunities for spectrum sharing in the 3.5GHz band
In this paper, we evaluate the opportunities that Wireless Network Virtualization (WNV) can bring for spectrum sharing by focusing on the regulatory framework that has been deployed by the Federal Communications Commission (FCC) for the 3.5GHz band. We pair this innovative regulatory approach with another novel arrangement, Wireless Network Virtualization, and thus assess the resulting opportunities from the perspectives of regulation, technology and economics. To this end, we have established a comprehensive foundation for further exploration and development of virtualized networks that would provide significant opportunities for enabling and enhancing current sharing arrangements
Wireless Network Virtualization: Opportunities for Spectrum Sharing in the 3.5GHz Band
In this paper, we evaluate the opportunities that Wireless Network Virtualization (WNV) can bring for spectrum sharing by focusing on the regulatory framework that has been deployed by the Federal Communications Commission (FCC) for the 3.5GHz band. Pairing this regulatory approach with WNV permits us to present a sharing proposal where emphasis is made on increasing resource availability and providing flexible methods for negotiating for resource access. We include an economics framework that aims at presenting an additional perspective on the attainable outcomes of our sharing proposal. We find that by pairing regulatory flexibility with an enabling technology, within an appropriate economics context, we can increase resource access opportunities and enhance current sharing arrangements
How can polycentric governance of spectrum work?
Spectrum policy in the US (and throughout most of the world) consists generally of a set of nationally determined policies that apply uniformly to all localities. However, it is also true that there is considerable variation in the features (e.g., traffic demand or population density), requirements and constraints of spectrum use on a local basis. Global spectrum policies designed to resolve a situation in New York City could well be overly restrictive for communities in rural areas (such as central Wyoming). At the same time, it is necessary to ensure that more permissive policies of central Wyoming would not create problems for NYC (by ensuring, for example, that relocated radios adapt to local policies). Notions of polycentric governance that have been articulated by the late E. Ostrom [16] argue that greater good can be achieved by allowing for local autonomy in resource allocation. Shared access to spectrum is generally mediated through one of several technologies. As shown in [21], approaches mediated by geolocation databases are the most cost effective in today's technology. In the database oriented Spectrum Access System, or SAS, proposed by the FCC, users are granted (renewable) usage rights based on their location for a limited period of time. Because this system grants usage rights on a case-by-case basis, it may also allow for greater local autonomy while still maintaining global coordination. For example, it would be technically feasible for the database to include parameters such as transmit power, protocol, and bandwidth. Thus, they may provide the platform by which polycentric governance might come to spectrum management. In this paper, we explore, through some case examples, what polycentric governance of spectrum might look like and how this could be implemented in a database-driven spectrum management system. In many ways this paper is a complement to [20], which evaluted emerging SAS architectures using Ostrom's socioeconomic theory. This paper explores how a SAS-based system could be constructed that is consistent with Ostrom's polycentric governance ideas. Our approach is to address spectrum management as an emergent phenomenon rather than a top down system. This paper will describe the key details of this system and present some initial modeling results in comparison with the traditional global model of spectrum regulation. It will also discuss some of the concerns associated with this approach
Dimensions of cooperative spectrum sharing: Rights and enforcement
Sharing of radio spectrum requires a careful and nuanced understanding of the rights of incumbents and spectrum entrants. In addition, the dynamics of stakeholders can be understood by examining how various rights are arranged (and rearranged) among them. Importantly, understanding the rights and their distribution is the predicate to developing rational and useful enforcement approaches. In this paper, we show that spectrum sharing involves a rearrangement of the rights associated with radio spectrum among stakeholders. We show how this rearrangement of rights implies the definition of new bundles of rights, appropriate to each particular sharing scenario. We discover these rights - and their (re)arrangement - by examining several cases of spectrum use. We begin with the rights associated with exclusive use and proceed to consider rights arrangement in commons and different spectrum sharing configurations. Further, in the case of commons, we explicitly examine how governance of commons can affect the rights distribution in spectrum. In each case, the bundles of rights associated with each stakeholder changes. New bundles of rights have consequences, not only on the behavior of spectrum users but also on the enforcement process. Our examination of the bundles of rights shows that each rearrangement results in different approaches to enforcement. We demonstrate this by revisiting enforcement in the cases we examine. Β© 2014 IEEE
Socio-technical considerations for Spectrum Access System (SAS) design
Spectrum Access Systems (SAS) are emerging as a principal mechanism for managing the sharing of radio spectrum. The design of the SAS depends on the specification of spectrum property rights and the governance system by which those rights are enforced. Current perspectives on SAS design have been too limited, focusing narrowly on the technical components without adequate consideration of socio-technical factors that will impact the likely success of any SAS design. In this paper, we apply the social science literature on the management of common pool resources (CPR) to the design challenge for the SAS. Heretofore, too much of the discussion has focused on an overly simplistic characterization of the spectrum rights design space as a dichotomous choice between licensed v. unlicensed, markets v. government, and exclusive v. open. The CPR framework forces consideration of a wider class of design options, positioning the specifications of spectrum property rights more appropriately along a multi-dimensional continuum of rights bundles. The CPR framework highlights the importance of considering formal and informal, multi-layered institutional and market-based interactions among SAS stakeholders when designing a resource management system. We will explain how this leads one to view the SAS as a polycentric governance system (using the terminology in the CPR literature). By examining the economic and social context of spectrum sharing, we assert that these emerging systems must be sufficiently flexible to adapt to various forms of resource governance, which refers to the process by which rights are distributed among stakeholders, how those rights are enforced, and how the resource is managed. We illustrate how the insights from the CPR literature might be implemented in a prototype SAS architecture
Temperature effects on zoeal morphometric traits and intraspecific variability in the hairy crab Cancer setosus across latitude
International audiencePhenotypic plasticity is an important but often ignored ability that enables organisms, within species-specific physiological limits, to respond to gradual or sudden extrinsic changes in their environment. In the marine realm, the early ontogeny of decapod crustaceans is among the best known examples to demonstrate a temperature-dependent phenotypic response. Here, we present morphometric results of larvae of the hairy crab , the embryonic development of which took place at different temperatures at two different sites (Antofagasta, 23Β°45β² S; Puerto Montt, 41Β°44β² S) along the Chilean Coast. Zoea I larvae from Puerto Montt were significantly larger than those from Antofagasta, when considering embryonic development at the same temperature. Larvae from Puerto Montt reared at 12 and 16Β°C did not differ morphometrically, but sizes of larvae from Antofagasta kept at 16 and 20Β°C did, being larger at the colder temperature. Zoea II larvae reared in Antofagasta at three temperatures (16, 20, and 24Β°C) showed the same pattern, with larger larvae at colder temperatures. Furthermore, larvae reared at 24Β°C, showed deformations, suggesting that 24Β°C, which coincides with temperatures found during strong EL NiΓ±o events, is indicative of the upper larval thermal tolerance limit. Β is exposed to a wide temperature range across its distribution range of about 40Β° of latitude. Phenotypic plasticity in larval offspring does furthermore enable this species to locally respond to the inter-decadal warming induced by El NiΓ±o. Morphological plasticity in this species does support previously reported energetic trade-offs with temperature throughout early ontogeny of this species, indicating that plasticity may be a key to a species' success to occupy a wide distribution range and/or to thrive under highly variable habitat conditions
P19-12. Multimers of llama heavy chain variable domains that bind to the 2F5/4E10 epitope neutralize HIV-1
Innovator resilience potential: A process perspective of individual resilience as influenced by innovation project termination
Innovation projects fail at an astonishing rate. Yet, the negative effects of innovation project failures on the team members of these projects have been largely neglected in research streams that deal with innovation project failures. After such setbacks, it is vital to maintain or even strengthen project membersβ innovative capabilities for subsequent innovation projects. For this, the concept of resilience, i.e. project membersβ potential to positively adjust (or even grow) after a setback such as an innovation project failure, is fundamental. We develop the second-order construct of innovator resilience potential, which consists of six components β self-efficacy, outcome expectancy, optimism, hope, self-esteem, and risk propensity β that are important for project membersβ potential of innovative functioning in innovation projects subsequent to a failure. We illustrate our theoretical findings by means of a qualitative study of a terminated large-scale innovation project, and derive implications for research and management
A novel CCM2 variant in a family with non-progressive cognitive complaints and cerebral microbleeds
Lobar cerebral microbleeds are most often sporadic and associated with Alzheimer's disease. The aim of our study was to identify the underlying genetic defect in a family with cognitive complaints and multiple lobar microbleeds and a positive family history for early onset Alzheimer's disease. We performed exome sequencing followed by Sanger sequencing for validation purposes on genomic DNA of three siblings with cognitive complaints, reduced amyloid-beta-42 in CSF and multiple cerebral lobar microbleeds. We checked for the occurrence of the variant in a cohort of 363 patients with early onset dementia and/or microbleeds. A novel frameshift variant (c.236_237delAC) generating a premature stop codon in the CCM2 gene shared by all three siblings was identified. Pathogenicity of the variant was supported by the presence of cerebral cavernous malformations in two of the siblings and by the absence of the variant exome variant databases. Two siblings were homozygous for APOE-Ο΅4; one heterozygous. The cognitive complaints, reduced amyloid-beta-42 in CSF and microbleeds suggest preclinical Alzheimer's disease, but the stability of the cognitive complaints does not. We hypothesize that the phenotype in this family may be due to a combination of the CCM2 variant and the APOE status. Β© 2016 The Authors. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics Published by Wiley Periodicals, Inc
High resolution analysis of DNA copy-number aberrations of chromosomes 8, 13, and 20 in gastric cancers
DNA copy-number gains of chromosomes 8q, 13q, and 20q are frequently observed in gastric cancers. Moreover gain of chromosome 20q has been associated with lymph node metastasis. The aim of this study was to correlate DNA copy-number changes of individual genes on chromosomes 8q, 13q, and 20q in gastric adenocarcinomas to clinicopathological data. DNA isolated from 63 formalin-fixed and paraffin-embedded gastric adenocarcinoma tissue samples was analyzed by whole-genome microarray comparative genomic hybridization and by multiplex ligation-dependent probe amplification (MLPA), targeting 58 individual genes on chromosomes 8, 13, and 20. Using array comparative genomic hybridization, gains on 8q, 13q, and 20q were observed in 49 (77.8%), 25 (39.7%), and 49 (77.8%) gastric adenocarcinomas, respectively. Gain of chromosome 20q was significantly correlated with lymph node metastases (pβ=β0.05) and histological type (pβ=β0.02). MLPA revealed several genes to be frequently gained in DNA copy number. The oncogene c-myc on 8q was gained in 73% of the cancers, while FOXO1A and ATP7B on 13q were both gained in 28.6% of the cases. Multiple genes on chromosome 20q showed gains in more than 60% of the cancers. DNA copy-number gains of TNFRSF6B (20q13.3) and ZNF217 (20q13.2) were significantly associated with lymph node metastasis (pβ=β0.02) and histological type (pβ=β0.02), respectively. In summary, gains of chromosomes 8q, 13q, and 20q in gastric adenocarcinomas harbor DNA copy-number gains of known and putative oncogenes. ZNF217 and TNFRSF6B are associated with important clinicopathological variables, including lymph node status
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