On the validity of Strong Cosmic Censorship Conjecture in presence of Dirac fields

A well posed theory of nature is expected to determine the future of an observer uniquely from a given set of appropriate initial data. In the context of general relativity, this is ensured by Penrose's strong cosmic censorship conjecture. But in recent years, several examples are found which suggest breakdown of the deterministic nature of the theory in Reissner-Nordstrom-de Sitter black holes under the influence of different fundamental fields. Nevertheless, the situation has been reassuring for the case of astrophysically meaningful Kerr-de Sitter black hole solutions which seems to respect the conjecture. However, the previous analyses were done considering only the effect of scalar fields. In this paper, we extend the study by considering Dirac fields in Kerr-de Sitter background and show that there exist a parameter space which does not respect the conjecture.Comment: 13 pages, 2 figures, Accepted in European Physical Journal

Skybridge: A New Nanoscale 3-D Computing Framework for Future Integrated Circuits

Continuous scaling of CMOS has been the major catalyst in miniaturization of integrated circuits (ICs) and crucial for global socio-economic progress. However, continuing the traditional way of scaling to sub-20nm technologies is proving to be very difficult as MOSFETs are reaching their fundamental performance limits [1] and interconnection bottleneck is dominating IC operational power and performance [2]. Migrating to 3-D, as a way to advance scaling, has been elusive due to inherent customization and manufacturing requirements in CMOS architecture that are incompatible with 3-D organization. Partial attempts with die-die [3] and layer-layer [4] stacking have their own limitations [5]. We propose a new 3-D IC fabric technology, Skybridge [6], which offers paradigm shift in technology scaling as well as design. We co-architect Skybridge’s core aspects, from device to circuit style, connectivity, thermal management, and manufacturing pathway in a 3-D fabric-centric manner, building on a uniform 3-D template. Our extensive bottom-up simulations, accounting for detailed material system structures, manufacturing process, device, and circuit parasitics, carried through for several designs including a designed microprocessor, reveal a 30-60x density, 3.5x performance/watt benefits, and 10x reduction in interconnect lengths vs. scaled 16-nm CMOS [6]. Fabric-level heat extraction features are found to be effective in managing IC thermal profiles in 3-D. This 3-D integrated fabric proposal overcomes the current impasse of CMOS in a manner that can be immediately adopted, and offers unique solution to continue technology scaling in the 21st century

A Game-theoretic Model for Regulating Freeriding in Subsidy-Based Pervasive Spectrum Sharing Markets

Cellular spectrum is a limited natural resource becoming scarcer at a worrisome rate. To satisfy users\u27 expectation from wireless data services, researchers and practitioners recognized the necessity of more utilization and pervasive sharing of the spectrum. Though scarce, spectrum is underutilized in some areas or within certain operating hours due to the lack of appropriate regulatory policies, static allocation and emerging business challenges. Thus, finding ways to improve the utilization of this resource to make sharing more pervasive is of great importance. There already exists a number of solutions to increase spectrum utilization via increased sharing. Dynamic Spectrum Access (DSA) enables a cellular operator to participate in spectrum sharing in many ways, such as geological database and cognitive radios, but these systems perform spectrum sharing at the secondary level (i.e., the bands are shared if and only if the primary/licensed user is idle) and it is questionable if they will be sufficient to meet the future expectations of the spectral efficiency. Along with the secondary sharing, spectrum sharing among primary users is emerging as a new domain of future mode of pervasive sharing. We call this type of spectrum sharing among primary users as pervasive spectrum sharing (PSS) . However, such spectrum sharing among primary users requires strong incentives to share and ensuring a freeriding-free cellular market. Freeriding in pervasively shared spectrum markets (be it via government subsidies/regulations or self-motivated coalitions among cellular operators) is a real techno-economic challenge to be addressed. In a PSS market, operators will share their resources with primary users of other operators and may sometimes have to block their own primary users in order to attain sharing goals. Small operators with lower quality service may freeride on large operators\u27 infrastructure in such pervasively shared markets. Even worse, since small operators\u27 users may perceive higher-than-expected service quality for a lower fee, this can cause customer loss to the large operators and motivate small operators to continue freeriding with additional earnings from the stolen customers. Thus, freeriding can drive a shared spectrum market to an unhealthy and unstable equilibrium. In this work, we model the freeriding by small operators in shared spectrum markets via a game-theoretic framework. We focus on a performance-based government incentivize scheme and aim to minimize the freeriding issue emerging in such PSS markets. We present insights from the model and discuss policy and regulatory challenges

Enhancing the Power of Endogenous Protein Phosphatase 2A to Combat Asthmatic Inflammation: Role for MAPKs and Tristetraprolin

Asthma is a chronic inflammatory disease, and thus corticosteroids are the mainstay of anti-inflammatory therapy to combat the disease. Typically asthma management involves long term use of corticosteroids, which often leads to severe side effects. Although corticosteroids have proven clinical efficacy in asthma, many asthmatic inflammatory conditions (e.g. infection, exacerbation) are not responsive to them. Therefore, alternative anti-inflammatory strategies are urgently needed and enhancing the function of endogenous PP2A, offer great promise. PP2A is a master controller of multiple inflammatory signalling pathways driven by MAPKs and is a target in asthma. Therefore in this thesis I aim to explore the role of PP2A in the context of asthmatic inflammation. Studies performed in this thesis provide a greater understanding of the role of some widely used inflammatory mediators such as TNFα, S1P and Pam3CSK and most importantly, the anti-inflammatory impact of PP2A. Our studies partly revealed the underlying molecular mechanisms of endogenous PP2A and its relationship with the critical anti-inflammatory protein, TTP. Besides, these studies clearly demonstrate that PP2A activators can enhance the anti-inflammatory function of TTP and repress inflammation when corticosteroid insensitivity exists. Therefore we presume that PP2A activators may have implications as alternative anti-inflammatory strategies to combat asthmatic inflammation

Nanowire Volatile RAM as an Alternative to SRAM

Maintaining benefits of CMOS technology scaling is becoming challenging due to increased manufacturing complexities and unwanted passive power dissipations. This is particularly challenging in SRAM, where manufacturing precision and leakage power control are critical issues. To alleviate some of these challenges a novel non-volatile memory alternative to SRAM was proposed called nanowire volatile RAM (NWRAM). Due to NWRAMs regular grid based layout and innovative circuit style, manufacturing complexity is reduced and at the same time considerable benefits are attained in terms of performance and leakage power reduction. In this paper, we elaborate more on NWRAM circuit aspects and manufacturability, and quantify benefits at 16nm technology node through simulation against state-of-the-art 6T-SRAM and gridded 8T-SRAM designs. Our results show the 10T-NWRAM to be 2x faster and 35x better in terms of leakage when compared to high performance gridded 8T-SRAM design

A COMPARATIVE ANALYSIS OF BUILDING CONSTRUCTION RULES AND THEIR IMPACT ON INDOOR TEMPERATURE OF MULTISTORIED BUILDINGS

The International Energy Agency projected that global final energyconsumption in buildings would grow by 30 percent from 2007 to 2030 ifprevailing practices and trends continued. Most of that increase is expectedto come from fast growing developing countries. New buildings in Dhaka arebeing constructed under the 2008 building construction act, termed as 'Dhakamohanagar imarat nirman bidhimala 2008' focusing more on FAR (floor arearatio) offers vertical expansion than horizontal to accommodate the requiredfloor area through providing more open spaces. Increase in building heightswith certain setbacks resulted increase in possibilities of change in naturalindoor lighting at the lower level of the structures. As a result, use ofartificial lighting in indoor spaces may be increased which may result changein fossil fuel consumption for power generation. Beside the indoor daylighting condition the question arises what would be the situation in terms ofindoor temperature due to building to building setback? Is there any impactof indoor temperature due to the setback provided in the construction rulesand the building height achieved in this regard? Thus, this paper tries to findout through theoretical investigation whether there are any impact on indoortemperature at different floor levels due to the direct component of solarradiation; and finds out that building setback and building height due tobuilding regulations influences significantly on indoor temperature atdifferent floor levels within a structure due to direct component of solarradiation. Comparisons between 1996 and 2008 imarat nirman bidhimala arepresented specially for residential buildings. The southwest facade isanalyzed in depeer detail