31,499 research outputs found
An Intelligent Auxiliary Vacuum Brake System
The purpose of this paper focuses on designing an intelligent, compact, reliable, and robust auxiliary vacuum brake system (VBS) with Kalman filter and self-diagnosis scheme. All of the circuit elements in the designed system are integrated into one programmable system-on-chip (PSoC) with entire computational algorithms implemented by software. In this system, three main goals are achieved: (a) Kalman filter and hysteresis controller algorithms are employed within PSoC chip by software to surpass the noises and disturbances from hostile surrounding in a vehicle. (b) Self-diagnosis scheme is employed to identify any breakdown element of the auxiliary vacuum brake system. (c) Power MOSFET is utilized to implement PWM pump control and compared with relay control. More accurate vacuum pressure control has been accomplished as well as power energy saving. In the end, a prototype has been built and tested to confirm all of the performances claimed above
Web-Based Collaborative Learning
AbstractThe development of information technology, especially the rapid development of multimedia technology and the network technology, provide better development for collaborative learning. Compared to traditional collaborative learning, web-based collaborative learning has the characteristics of interaction timeliness, space flexibility, object-oriented widely, etc. Web-based collaborative learning refers to let learners finish their studies through network. This learning style helps to promote the students’ cognitive activities, improve their abilities of resolving and dealing with the problems. This paper relates and analyzes the collaborative learning under network environment
On Heterogeneous Neighbor Discovery in Wireless Sensor Networks
Neighbor discovery plays a crucial role in the formation of wireless sensor
networks and mobile networks where the power of sensors (or mobile devices) is
constrained. Due to the difficulty of clock synchronization, many asynchronous
protocols based on wake-up scheduling have been developed over the years in
order to enable timely neighbor discovery between neighboring sensors while
saving energy. However, existing protocols are not fine-grained enough to
support all heterogeneous battery duty cycles, which can lead to a more rapid
deterioration of long-term battery health for those without support. Existing
research can be broadly divided into two categories according to their
neighbor-discovery techniques---the quorum based protocols and the co-primality
based protocols.In this paper, we propose two neighbor discovery protocols,
called Hedis and Todis, that optimize the duty cycle granularity of quorum and
co-primality based protocols respectively, by enabling the finest-grained
control of heterogeneous duty cycles. We compare the two optimal protocols via
analytical and simulation results, which show that although the optimal
co-primality based protocol (Todis) is simpler in its design, the optimal
quorum based protocol (Hedis) has a better performance since it has a lower
relative error rate and smaller discovery delay, while still allowing the
sensor nodes to wake up at a more infrequent rate.Comment: Accepted by IEEE INFOCOM 201
Resonant sequential scattering in two-frequency-pumping superradiance from a Bose-Einstein condensate
We study sequential scattering in superradiance from a Bose-Einstein
condensate pumped by a two-frequency laser beam. We find that the distribution
of atomic side modes presents highly different patterns for various frequency
difference between the two pump components. A novel distribution is observed,
with a frequency difference of eight times the recoil frequency. These
observations reveal that the frequency overlap between the end-fire modes
related to different side modes plays an essential role in the dynamics of
sequential superradiant scattering. The numerical results from a semiclassical
model qualitatively agree with our observations.Comment: Submitted to PR
Electronic band gaps and transport properties in periodically alternating mono- and bi-layer graphene superlattices
We investigate the electronic band structure and transport properties of
periodically alternating mono- and bi-layer graphene superlattices (MBLG SLs).
In such MBLG SLs, there exists a zero-averaged wave vector
(zero-) gap that is insensitive to the lattice constant. This
zero- gap can be controlled by changing both the ratio of the
potential widths and the interlayer coupling coefficient of the bilayer
graphene. We also show that there exist extra Dirac points; the conditions for
these extra Dirac points are presented analytically. Lastly, we demonstrate
that the electronic transport properties and the energy gap of the first two
bands in MBLG SLs are tunable through adjustment of the interlayer coupling and
the width ratio of the periodic mono- and bi-layer graphene.Comment: More discussion is added and the English is polished. Accepted for
publication in EP
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