Machine Learning-based Indoor Positioning Systems Using Multi-Channel Information

The received signal strength indicator (RSSI) is a metric of the power measured by a sensor in a receiver. Many indoor positioning technologies use RSSI to locate objects in indoor environments. Their positioning accuracy is significantly affected by reflection and absorption from walls, and by non-stationary objects such as doors and people. Therefore, it is necessary to increase transceivers in the environment to reduce positioning errors. This paper proposes an indoor positioning technology that uses the machine learning algorithm of channel state information (CSI) combined with fingerprinting. The experimental results showed that the proposed method outperformed traditional RSSI-based localization systems in terms of average positioning accuracy up to 6.13% and 54.79% for random forest (RF) and back propagation neural networks (BPNN), respectively

Machine Learning-based Indoor Positioning Systems Using Multi-Channel Information

The received signal strength indicator (RSSI) is a metric of the power measured by a sensor in a receiver. Many indoor positioning technologies use RSSI to locate objects in indoor environments. Their positioning accuracy is significantly affected by reflection and absorption from walls, and by non-stationary objects such as doors and people. Therefore, it is necessary to increase transceivers in the environment to reduce positioning errors. This paper proposes an indoor positioning technology that uses the machine learning algorithm of channel state information (CSI) combined with fingerprinting. The experimental results showed that the proposed method outperformed traditional RSSI-based localization systems in terms of average positioning accuracy up to 6.13% and 54.79% for random forest (RF) and back propagation neural networks (BPNN), respectively

ICT Integrated in Higher Education: The Activities, Context and Effects

Accompanying with the development and advancement of ICT integrated in higher education, it enabled the progressive changes in centered pedagogies and practices. This study attempts to explore the context in ICT integrated education with student perspective and to propose a research model combining with readiness and activity theory to exam the effects of ICT integrated in higher education and the learning performance. 603 questionnaires were collected from the universities in Taiwan and analyzed with AMOS. The results indicate that informational-based readiness has positive effect on user’s readiness, user’s readiness and schools’ ICT support both have positive effects on ICT actual use, and ICT actual use also has positive effect on their perceived satisfaction (performance). The findings could enrich the research of ICT integrated education with different perspectives, and would be helpful to extend to the long-term development in academics and practical ICT application

Maternal and Hospital Factors Associated with First-Time Mothers' Breastfeeding Practice: A Prospective Study

Continuity of breastfeeding is infrequent and indeterminate. Evidence is lacking regarding factors associated with breastfeeding at different postpartum time points. This prospective study investigated the change in, and correlates of, breastfeeding practices after delivery at a hospital and at 1, 3, and 6 months postpartum among first-time mothers. We followed a cohort of 300 primiparous mothers of Taiwan who gave birth at two hospitals during 2010?2011. Logistic and Cox regression analyses were performed to determine factors that were correlated with breastfeeding practices. In the study sample, the rate of exclusive breastfeeding during the hospital stay was 66%; it declined to 37.5% at 1 month and 30.2% at 3 months postpartum. Only 17.1% of women reported continuing breastfeeding at 6 months. Early initiation of breastfeeding, rooming-in practice, and self-efficacy were significantly related to exclusive breastfeeding during the hospital stay. After discharge, health literacy, knowledge, intention, and self-efficacy were positively and significantly associated with breastfeeding exclusivity. Later initiation (hazard ratio=1.53; 95% confidence interval, 1.05, 1.97), shorter intention (hazard ratio=1.42; 95% confidence interval, 1.13, 1.68), and self-efficacy (hazard ratio=0.98; 95% confidence interval, 0.96, 0.99) were important predictors of breastfeeding cessation within 6 months of delivery. Continuous breastfeeding practice for 6 months is challenging and difficult for new mothers. Results showed that factors related to breastfeeding varied over time after delivery. Interventions seeking to sustain breastfeeding should consider new mothers' needs and barriers at different times.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140313/1/bfm.2015.0005.pd

Logarithmic singularities and quantum oscillations in magnetically doped topological insulators

We report magnetotransport measurements on magnetically doped (Bi,Sb)$_2$Te$_3$ films grown by molecular beam epitaxy. In Hallbar devices, logarithmic dependence on temperature and bias voltage are obseved in both the longitudinal and anomalous Hall resistance. The interplay of disorder and electron-electron interactions is found to explain quantitatively the observed logarithmic singularities and is a dominant scattering mechanism in these samples. Submicron scale devices exhibit intriguing quantum oscillations at high magnetic fields with dependence on bias voltage. The observed quantum oscillations can be attributed to bulk and surface transport.Comment: 10 pages, 13 figure

Existence theorems for a crystal surface model involving the p-Laplace operator

The manufacturing of crystal films lies at the heart of modern nanotechnology. How to accurately predict the motion of a crystal surface is of fundamental importance. Many continuum models have been developed for this purpose, including a number of PDE models, which are often obtained as the continuum limit of a family of kinetic Monte Carlo models of crystal surface relaxation that includes both the solid-on-solid and discrete Gaussian models. In this paper we offer an analytical perspective into some of these models. To be specific, we study the existence of a weak solution to the boundary value problem for the equation - \Delta e^{-\mbox{div}\left(|\nabla u|^{p-2}\nabla u\right)}+au=f, where $p>1, a>0$ are given numbers and $f$ is a given function. This problem is derived from a crystal surface model proposed by J.L.~Marzuola and J.~Weare (2013 Physical Review, E 88, 032403). The mathematical challenge is due to the fact that the principal term in our equation is an exponential function of a p-Laplacian. Existence of a suitably-defined weak solution is established under the assumptions that $p\in(1,2], \ N\leq 4$, and $f\in W^{1,p}$. Our investigations reveal that the key to our existence assertion is how to control the set where -\mbox{div}\left(|\nabla u|^{p-2}\nabla u\right) is $\pm\infty$

Sodium vacancy ordering and the co-existence of localized spins and itinerant charges in NaxCoO2

The sodium cobaltate family (NaxCoO2) is unique among transition metal oxides because the Co sits on a triangular lattice and its valence can be tuned over a wide range by varying the Na concentration x. Up to now detailed modeling of the rich phenomenology (which ranges from unconventional superconductivity to enhanced thermopower) has been hampered by the difficulty of controlling pure phases. We discovered that certain Na concentrations are specially stable and are associated with superlattice ordering of the Na clusters. This leads naturally to a picture of co-existence of localized spins and itinerant charge carriers. For x = 0.84 we found a remarkably small Fermi energy of 87 K. Our picture brings coherence to a variety of measurements ranging from NMR to optical to thermal transport. Our results also allow us to take the first step towards modeling the mysterious ``Curie-Weiss'' metal state at x = 0.71. We suggest the local moments may form a quantum spin liquid state and we propose experimental test of our hypothesis.Comment: 16 pages, 5 figure