290 research outputs found
Synthesis inequalities for the robust PID controller for a DC Servo motor and Implementation by using digital signal processor
Encoding for the Blackwell Channel with Reinforced Belief Propagation
A key idea in coding for the broadcast channel (BC) is binning, in which the
transmitter encode information by selecting a codeword from an appropriate bin
(the messages are thus the bin indexes). This selection is normally done by
solving an appropriate (possibly difficult) combinatorial problem. Recently it
has been shown that binning for the Blackwell channel --a particular BC-- can
be done by iterative schemes based on Survey Propagation (SP). This method uses
decimation for SP and suffers a complexity of O(n^2). In this paper we propose
a new variation of the Belief Propagation (BP) algorithm, named Reinforced BP
algorithm, that turns BP into a solver. Our simulations show that this new
algorithm has complexity O(n log n). Using this new algorithm together with a
non-linear coding scheme, we can efficiently achieve rates close to the border
of the capacity region of the Blackwell channel.Comment: 5 pages, 8 figures, submitted to ISIT 200
On the structure and evolution of planets and their host stars effects of various heating mechanisms on the size of giant gas planets
It is already stated in the previous studies that the radius of the giant
planets is affected by stellar irradiation. The confirmed relation between
radius and incident flux depends on planetary mass intervals. In this study, we
show that there is a single relation between radius and irradiated energy per
gram per second (), for all mass intervals. There is an extra increase in
radius of planets if is higher than 1100 times energy received by the
Earth (). This is likely due to dissociation of molecules. The tidal
interaction as a heating mechanism is also considered and found that its
maximum effect on the inflation of planets is about 15 per cent. We also
compute age and heavy element abundances from the properties of host stars,
given in the TEPCat catalogue (Southworth 2011). The metallicity given in the
literature is as [Fe/H]. However, the most abundant element is oxygen, and
there is a reverse relation between the observed abundances [Fe/H] and [O/Fe].
Therefore, we first compute [O/H] from [Fe/H] by using observed abundances, and
then find heavy element abundance from [O/H]. We also develop a new method for
age determination. Using the ages we find, we analyse variation of both radius
and mass of the planets with respect to time, and estimate the initial mass of
the planets from the relation we derive for the first time. According to our
results, the highly irradiated gas giants lose 5 per cent of their mass in
every 1 Gyr.Comment: 15 pages, 13 figures, 3 tables. Accepted by MNRA
Compact massive objects in Virgo galaxies: the black hole population
We investigate the distribution of massive black holes (MBHs) in the Virgo
cluster. Observations suggest that AGN activity is widespread in massive
galaxies (M>1e10 solar masses), while at lower galaxy masses star clusters are
more abundant, which might imply a limited presence of central black holes in
these galaxy-mass regimes. We explore if this possible threshold in MBH
hosting, is linked to nature, nurture, or a mixture of both. The nature
scenario arises naturally in hierarchical cosmologies, as MBH formation
mechanisms typically are efficient in biased systems, which would later evolve
into massive galaxies. Nurture, in the guise of MBH ejections following MBH
mergers, provides an additional mechanism that is more effective for low mass,
satellite galaxies. The combination of inefficient formation, and lower
retention of MBHs, leads to the natural explanation of the distribution of
compact massive ob jects in Virgo galaxies. If MBHs arrive to the correlation
with the host mass and velocity dispersion during merger-triggered accretion
episodes, sustained tidal stripping of the host galaxies creates a population
of MBHs which lie above the expected scaling between the holes and their host
mass, suggesting a possible environmental dependence.Comment: MNRAS letter
In vivo function of the murid herpesvirus-4 ribonucleotide reductase small subunit
The difficulty of eliminating herpesvirus carriage makes host entry a key target for infection control. However, its viral requirements are poorly defined. Murid herpesvirus-4 (MuHV-4) can potentially provide insights into gammaherpesvirus host entry. Upper respiratory tract infection requires the MuHV-4 thymidine kinase (TK) and ribonucleotide reductase large subunit (RNR-L), suggesting a need for increased nucleotide production. However, both TK and RNR-L are likely to be multifunctional. We therefore tested further the importance of nucleotide production by disrupting the MuHV-4 ribonucleotide reductase small subunit (RNR-S). This caused a similar attenuation to RNR-L disruption: despite reduced intra-host spread, invasive inoculations still established infection, whereas a non-invasive upper respiratory tract inoculation did so only at high dose. Histological analysis showed that RNR-S−, RNR-L− and TK− viruses all infected cells in the olfactory neuroepithelium but unlike wild-type virus then failed to spread. Thus captured host nucleotide metabolism enzymes, up to now defined mainly as important for alphaherpesvirus reactivation in neurons, also have a key role in gammaherpesvirus host entry. This seemed to reflect a requirement for lytic replication to occur in a terminally differentiated cell before a viable pool of latent genomes could be established
The moderating effect of brand orientation on inter-firm market orientation and performance
While prior research has shown that market and brand orientation
are key contributors to successful business performance, research to
date has not fully explored how inter firm collaboration for these two
key orientations can enhance business performance. The purpose of
the paper is to investigate the relationship between inter-firm market
and performance; to test for the moderating role of brand orientation
in that relationship. A total of 169 completed pairs of surveys were
collected of small and medium enterprises operating internationally
in a variety of industries in Switzerland. The results show that inter-firm
market and brand orientation are two antecedents of marketing and
financial performance. The impact of inter-firm market on marketing
and financial performance is significant when the brand orientation
is favorable. This study extends previous research by examining the
moderating role of brand orientation on inter firm market orientation,
which is important, especially for firms wanting to increase their brand
reputation by entering into partnerships with other firms. Further
research is indicated, to identify the key moderators of the driving
force of inter-firm market in relation to business performance and
the reason why maintaining a strong brand presence is important in
the international marketplace
Murid herpesvirus-4 lacking thymidine kinase reveals route-dependent requirements for host colonization
Gammaherpesviruses infect at least 90 % of the world's population. Infection control is difficult, in part because some fundamental features of host colonization remain unknown, for example whether normal latency establishment requires viral lytic functions. Since human gammaherpesviruses have narrow species tropisms, answering such questions requires animal models. Murid herpesvirus-4 (MuHV-4) provides one of the most tractable. MuHV-4 genomes delivered to the lung or peritoneum persist without lytic replication. However, they fail to disseminate systemically, suggesting that the outcome is inoculation route-dependent. After upper respiratory tract inoculation, MuHV-4 infects mice without involving the lungs or peritoneum. We examined whether host entry by this less invasive route requires the viral thymidine kinase (TK), a gene classically essential for lytic replication in terminally differentiated cells. MuHV-4 TK knockouts delivered to the lung or peritoneum were attenuated but still reached lymphoid tissue. In contrast, TK knockouts delivered to the upper respiratory tract largely failed to establish a detectable infection. Therefore TK, and by implication lytic replication, is required for MuHV-4 to establish a significant infection by a non-invasive route
Beaconing Approaches in Vehicular Ad Hoc Networks: A Survey
A Vehicular Ad hoc Network (VANET) is a type of wireless ad hoc network that facilitates
ubiquitous connectivity between vehicles in the absence of fixed infrastructure. Beaconing approaches
is an important research challenge in high mobility vehicular networks with enabling safety applications.
In this article, we perform a survey and a comparative study of state-of-the-art adaptive beaconing
approaches in VANET, that explores the main advantages and drawbacks behind their design. The
survey part of the paper presents a review of existing adaptive beaconing approaches such as adaptive
beacon transmission power, beacon rate adaptation, contention window size adjustment and Hybrid
adaptation beaconing techniques. The comparative study of the paper compares the representatives of
adaptive beaconing approaches in terms of their objective of study, summary of their study, the utilized
simulator and the type of vehicular scenario. Finally, we discussed the open issues and research
directions related to VANET adaptive beaconing approaches.Ghafoor, KZ.; Lloret, J.; Abu Bakar, K.; Sadiq, AS.; Ben Mussa, SA. (2013). Beaconing Approaches in Vehicular Ad Hoc Networks: A Survey. Wireless Personal Communications. 73(3):885-912. doi:10.1007/s11277-013-1222-9S885912733ITS-Standards (1996) Intelligent transportation systems, U.S. Department of Transportation, http://www.standards.its.dot.gov/about.aspCheng, L., Henty, B., Stancil, D., Bai, F., & Mudalige, P. (2005). Mobile vehicle-to-vehicle narrow-band channel measurement and characterization of the 5.9 Ghz dedicated short range communication (DSRC) frequency band. IEEE Transactions on Selected Areas in Communications, 25(8), 1501–1516.van Eenennaam, E., Wolterink, K., Karagiannis, G., & Heijenk, G. (2009). Exploring the solution space of beaconing in vanets. In Proceedings of the 2009 IEEE international vehicular networking conference, Tokyo (pp. 1–8).Torrent-Moreno, M. (2007). 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