3,489 research outputs found
The Williams Conjecture is false for irreducible subshifts
We show the Williams Conjecture is false for irreducible shifts of finite
type by examining relative sign-gyration numbers of conjugacies between shifts
with no points of period one or two.Comment: 14 pages, published versio
Gait Verification using Knee Acceleration Signals
A novel gait recognition method for biometric applications is proposed. The approach has the following distinct features. First, gait patterns are determined via knee acceleration signals, circumventing difficulties associated with conventional vision-based gait recognition methods. Second, an automatic procedure to extract gait features from acceleration signals is developed that employs a multiple-template classification method. Consequently, the proposed approach can adjust the sensitivity and specificity of the gait recognition system with great flexibility. Experimental results from 35 subjects demonstrate the potential of the approach for successful recognition. By setting sensitivity to be 0.95 and 0.90, the resulting specificity ranges from 1 to 0.783 and 1.00 to 0.945, respectively
Holographic Non-Fermi Liquid in a Background Magnetic Field
We study the effects of a non-zero magnetic field on a class of 2+1 dim
non-Fermi liquids, recently found in 0903.2477 by considering properties of a
fermionic probe in an extremal AdS^4 black hole background. Introducing a
similar fermionic probe in a dyonic AdS^4 black hole geometry, we find that the
effect of a magnetic field could be incorporated in a rescaling of the probe
fermion's charge. From this simple fact, we observe interesting effects like
gradual disappearance of the Fermi surface and quasi particle peaks at large
magnetic fields and changes in other properties of the system. We also find
Landau level like structures and oscillatory phenomena similar to the de
Haas-van Alphen effect.Comment: 20 pages, latex, 6 figure
Non-Markovian disentanglement dynamics of two-qubit system
We investigated the disentanglement dynamics of two-qubit system in
Non-Markovian approach. We showed that only the couple strength with the
environment near to or less than fine-structure constant 1/137, entanglement
appear exponential decay for a certain class of two-qubit entangled state.
While the coupling between qubit and the environment is much larger, system
always appears the sudden-death of entanglement even in the vacuum environment.Comment: 17 pages, 3 figure
Sistem Peringatan Dini Akan Bahaya Kebakaran
Fire disaster is one from many other disasters that very dangerous because not only it's took heavy financial and material loss, but also often takes lives. For this reason, it needs the system which can give early warning not only to the people around the building but also to the building owner. This system must also work to delay fire spreading. This paper discuss the designing and implementation of early warning system to help minimize loss from fire disaster
Calibration of YSZ Sensors for the Measurement of Oxygen Concentration in Liquid Pb-Bi Eutectic
Although liquid lead-bismuth eutectic (LBE) is a good candidate for coolant in the subcritical transmutation blanket, it is known to be corrosive to stainless steel, the material of the carrying tubes and containers. Such longterm corrosion problem can be prevented by producing and maintaining a protective oxide layer on the exposed surface of stainless steel. For this purpose, it is required to accurately control the concentration of oxygen dissolved in LBE. Currently, YSZ (Yttria Stabilized Zirconia) oxygen sensors, based on an existing automotive oxygen sensor, with molten bismuth saturated with oxygen as the reference, have been selected for oxygen-concentration measurement. The oxygen concentration difference across the solid electrolyte and the resultant oxygen ion conduction inside the electrolyte establishes an electromagnetic force that is used to measure the ppb level concentration of oxygen dissolved in liquid LBE. A set of calibration curves of voltage vs. temperature ranging from 300 0C to 500 0C under various oxygen concentrations in liquid LBE for the YSZ oxygen sensor has been obtained and is presented in this paper. Although the current calibration strategy using the direct injection of hydrogen and oxygen is still inadequate to determine the oxygen concentration in the system, we have found a good candidate for our purpose, which is varying hydrogen to water steam ratio in the system
Deliberation in Mobile Messaging Application: A Case in Hong Kong
Considering the increasing penetration of Internet and mobile technologies, we can foresee that more online debates and political discussions, such as online deliberations, will occur in the future. However, prior research does not illustrate or provide empirical evidence to support steps that that online deliberation should take. To address this gap, we conduct a case study on Project ThunderGo, an online deliberation campaign related to the 2016 Hong Kong Legislative Election. Via analyzing data obtained from their deliberation groups, the relevant news articles, and the election results, we establish a four-stage building, engineering, arriving, and reaching (BEAR) model of online deliberation and provide some practical implications for future deliberation host. The model and implications articulate ICT’s role in addressing complicated and multi-facet social problems
Time-Varying Priority Queuing Models for Human Dynamics
Queuing models provide insight into the temporal inhomogeneity of human
dynamics, characterized by the broad distribution of waiting times of
individuals performing tasks. We study the queuing model of an agent trying to
execute a task of interest, the priority of which may vary with time due to the
agent's "state of mind." However, its execution is disrupted by other tasks of
random priorities. By considering the priority of the task of interest either
decreasing or increasing algebraically in time, we analytically obtain and
numerically confirm the bimodal and unimodal waiting time distributions with
power-law decaying tails, respectively. These results are also compared to the
updating time distribution of papers in the arXiv.org and the processing time
distribution of papers in Physical Review journals. Our analysis helps to
understand human task execution in a more realistic scenario.Comment: 8 pages, 6 figure
Scaling properties of a low-actuation pressure microfluidic valve
Using basic physical arguments, we present a design and method for the fabrication of microfluidic valves using multilayer soft lithography. These on-off valves have extremely low actuation pressures and can be used to fabricate active functions, such as pumps and mixers in integrated microfluidic chips. We characterized the performance of the valves by measuring both the actuation pressure and flow resistance over a wide range of design parameters, and compared them to both finite element simulations and alternative valve geometries
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