1,770 research outputs found
In situ characterization of two wireless transmission schemes for ingestible capsules
We report the experimental in situ characterization of 30-40 MHz and 868 MHz wireless transmission schemes for ingestible capsules, in porcine carcasses. This includes a detailed study of the performance of a magnetically coupled near-field very high-frequency (VHF) transmission scheme that requires only one eighth of the volume and one quarter of the power consumption of existing 868-MHz solutions. Our in situ measurements tested the performance of four different capsules specially constructed for this study (two variants of each transmission scheme), in two scenarios. One mimicked the performance of a body-worn receiving coil, while the other allowed the characterization of the direction-dependent signal attenuation due to losses in the surrounding tissue. We found that the magnetically coupled near-field VHF telemetry scheme presents an attractive option for future, miniturized ingestible capsules for medical applications
Meson-Baryon-Baryon Vertex Function and the Ward-Takahashi Identity
Ohta proposed a solution for the well-known difficulty of satisfying the
Ward-Takahashi identity for a photo-meson-baryon-baryon amplitude (MBB)
when a dressed meson-baryon-baryon (MBB) vertex function is present. He
obtained a form for the MBB amplitude which contained, in addition to
the usual pole terms, longitudinal seagull terms which were determined entirely
by the MBB vertex function. He arrived at his result by using a Lagrangian
which yields the MBB vertex function at tree level. We show that such a
Lagrangian can be neither hermitian nor charge conjugation invariant. We have
been able to reproduce Ohta's result for the MBB amplitude using the
Ward-Takahashi identity and no other assumption, dynamical or otherwise, and
the most general form for the MBB and MBB vertices. However, contrary
to Ohta's finding, we find that the seagull terms are not robust. The seagull
terms extracted from the MBB vertex occur unchanged in tree graphs,
such as in an exchange current amplitude. But the seagull terms which appear in
a loop graph, as in the calculation of an electromagnetic form factor, are, in
general, different. The whole procedure says nothing about the transverse part
of the (MBB) vertex and its contributions to the amplitudes in
question.Comment: A 20 pages Latex file and 16 Postscript figures in an uuencoded
format. Use epsf.sty to include the figures into the Latex fil
Quantum wave equation of photon
In this paper, we give the quantum wave equations of single photon when it is
in the free or medium space. With these equations, we can study light
interference and diffraction with quantum approach. Otherwise, they can be
applied in quantum optics and photonic crystal.Comment: 8 pages, 0 figure
Role of disorder in half-filled high Landau levels
We study the effects of disorder on the quantum Hall stripe phases in
half-filled high Landau levels using exact numerical diagonalization. We show
that, in the presence of weak disorder, a compressible, striped charge density
wave, becomes the true ground state. The projected electron density profile
resembles that of a smectic liquid. With increasing disorder strength W, we
find that there exists a critical value, W_c \sim 0.12 e^2/\epsilon l, where a
transition/crossover to an isotropic phase with strong local electron density
fluctuations takes place. The many-body density of states are qualitatively
distinguishable in these two phases and help elucidate the nature of the
transition.Comment: 4 pages, 4 figure
Evaluating the semantic web: a task-based approach
The increased availability of online knowledge has led to the design of several algorithms that solve a variety of tasks by harvesting the Semantic Web, i.e. by dynamically selecting and exploring a multitude of online ontologies. Our hypothesis is that the performance of such novel algorithms implicity provides an insight into the quality of the used ontologies and thus opens the way to a task-based evaluation of the Semantic Web. We have investigated this hypothesis by studying the lessons learnt about online ontologies when used to solve three tasks: ontology matching, folksonomy enrichment, and word sense disambiguation. Our analysis leads to a suit of conclusions about the status of the Semantic Web, which highlight a number of strengths and weaknesses of the semantic information available online and complement the findings of other analysis of the Semantic Web landscape
Curvature of the universe and the dark energy potential
The flatness of an accelerating universe model (characterized by a dark
energy scalar field ) is mimicked from a curved model that is filled
with, apart from the cold dark matter component, a quintessencelike scalar
field . In this process, we characterize the original scalar potential
and the mimicked scalar potential associated to the scalar
fields and , respectively. The parameters of the original model are
fixed through the mimicked quantities that we relate to the present
astronomical data, such that the equation state parameter and the
dark energy density parameter .Comment: References 7 and 8 have been corrected: (7) Riess et al. 1998, AJ,
116, 1009 and (8) Perlmutter et al. 1999, ApJ, 517, 56
Analysis of the doubly heavy baryons in the nuclear matter with the QCD sum rules
In this article, we study the doubly heavy baryon states ,
, and in the nuclear matter using the QCD
sum rules, and derive three coupled QCD sum rules for the masses, vector
self-energies and pole residues. The predictions for the mass-shifts in the
nuclear matter , , and
can be confronted with the
experimental data in the future.Comment: 10 pages, 4 figure
Supporting learning with 3D interactive applications in early years
Early years education is an key element for the introduction of children in the education system. In order to improve this process, the aim of this study was to explore how guided interaction with 3D apps can fit into a preschool setting, how it can help children learn through playing and how it can improve their learning outcomes. A study was conducted with six classes of 87 students aged between 3 years to 6 years, over a 12-week period. Children used 10 inch Android tablets with a series of apps developed by our research team, about houses of the world, the skeleton & five senses and, animals. A quasi-experimental design based on a nonequivalent groups pretest and posttest de-sign revealed that an active behavior and better learning outcomes are obtained by children participating in the experimental groupCascales MartĂnez, A.; MartĂnez Segura, MJ.; Laguna- Segobia, M.; PĂ©rez Lopez, DC.; Contero, M. (2014). Supporting learning with 3D interactive applications in early years. Lecture Notes in Computer Science. 8524:11-22. doi:10.1007/978-3-319-07485-6_2S11228524Plowman, L., Stephen, C.: Children, Play and Computers in Preschool Education. British Journal of Educational Technology 36(2), 145â157 (2005)Tootell, H., Plumb, M., Hadfield, C., Dawson, L.: Gestural Interface Technology in early childhood education: A framework for fully-engaged communication. In: Proceedings of the Annual Hawaii International Conference on System Sciences, art. no. 6479836, pp. 13â20 (2013)Marco, J., Cerezo, E.: Bringing Tabletop Technologies to Kindergarten Children. In: HCI 2009 International Conference on Human-Computer InteractionâCelebrating People and Technology, pp. 103â111. Springer, Heidelberg (2009)Heft, T.M., Swaminathan, S.: Using Computers in Early Childhood Classrooms: Teachersâ Attitudes, Skills and Practices. Journal of Early Childhood Research 6(4), 169â188 (2006)Wang, X.C., Ching, C.C.: Social Construction of Computer Experience in a First-Grade Classroom: Social Processes and Mediating Artifacts. Early Education and Development 14(3), 335â361 (2003)Couse, L.J., Chen, D.W.: A Tablet Computer for Young Children? Exploring Its Viability for Early Childhood Education. Journal of Research on Technology in Education 43(1), 75â98 (2012)Kearney, J.: Educating Young Children - Learning and Teaching in the Early Childhood Years. Early Childhood Teachersâ Association (ECTA Inc.) 3(18) (2012)Rankothge, W.H., Sendanayake, S.V., Sudarshana, R.G.P., Balasooriya, B.G.G.H., Alahapperuma, D.R., Mallawarachchi, Y.: Technology Assisted Tool for Learning Skills Development in Early Childhood. In: Proc. of 2012 International Conference on Advances in ICT for Emerging Regions (ICTer), pp. 165â168 (2012)Sandvik, M., SmĂžrdal, O., Ăsterud, S.: Exploring iPads in Practitionersâ Repertoires for Language Learning and Literacy Practices In Kindergarten. Nordic Journal of Digital Literacy 3(7), 204â221 (2012)Priyankara, K.W.T.G.T., Mahawaththa, D.C., Nawinna, D.P., Jayasundara, J.M.A., Tharuka, K.D.N., Rajapaksha, S.K.: Android Based e-Learning Solution for Early Childhood Education in Sri Lanka. In: Proceedings of the 8th International Conference on Computer Science & Education (ICCSE), pp. 715â718 (2013)Zanchi, C., Presser, A.L., Vahey, P.: Next Generation Preschool Math Demo: Tablet Games for Preschool Classrooms. In: Proceedings of the 12th International Conference on Interaction Design and Children, IDC 2013, pp. 527â530 (2013)Meyer, B.: Game-based Language Learning for Pre-School Children: A Design Perspective. Electronic Journal of e-Learning 11(1), 39â48 (2013)Straub, D.W.: Validating Instruments in MIS Research. MIS Quarterly 13(2), 147â169 (1989)Cook, T.D., Campbell, D.T., Day, A.: Quasi-experimentation: Design and Analysis Issues for Field Settings, pp. 19â21. Houghton Mifflin, Boston (1979)BuendĂa, L., Y Berrocal, E.: La Ătica de la InvestigaciĂłn Educativa. Ăgora Digital 1 (2011)Tojar, J., Serrano, J.: Ătica e InvestigaciĂłn Educativa. RELIEVE 6(2) (2000)Cascales, A., Laguna, I., PĂ©rez-LĂłpez, D., Perona, P., Contero, M.: 3D Interactive Applications on Tablets for Preschoolers: Exploring the Human Skeleton and the Senses. In: HernĂĄndez-Leo, D., Ley, T., Klamma, R., Harrer, A. (eds.) EC-TEL 2013. LNCS, vol. 8095, pp. 71â83. Springer, Heidelberg (2013
Signals of Disoriented Chiral Condensate
If a disoriented chiral condensate is created over an extended space-time
region following a rapid cooling in hadronic or nuclear collisions, the
misalignment of the condensate with the electroweak symmetry breaking can
generate observable effects in the processes which involve both strong and
electromagnetic interactions. We point out the relevance of the dilepton decay
of light vector mesons as a signal for formation of the disoriented condensate.
We predict that the decay \rho^0 to dileptons will be suppressed and/or the
\rho resonance peak widens, while the decay \omega to dileptons will not be
affected by the condensate.Comment: 13 pages in LaTeX, UCB-PTH-94/05, LBL-3533
Effective block sparse representation algorithm for DOA estimation with unknown mutual coupling
Unknown mutual coupling effect can degrade the performance of a direction of arrival (DOA) estimation method. In this letter, a new method is proposed for uniform linear arrays (ULAs) to tackle this problem. Considering the sparse representation exploiting the inherent structure of the received data, the effective block sparse representation and the convex optimization problem is constructed using the steering vector parameterizing method. The proposed solution based on the l1- SVD (singular value decomposition) can exploit the information provided by the whole array and the Toeplitz structure of the mutual coupling matrix (MCM) in the ULA. Simulation results are provided to demonstrate its performance with unknown mutual coupling in comparison with some existing methods
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