The telecommunications industry has seen a rapid boost within the last decade. New realities
and visions of functionalities in various telecommunications networks have brought forward the
concept of next-generation networks (NGNs). The competitions among operators for support-
ing various services, lowering of the cost of having mobile and cellular phones and smartphones,
increasing demand for general mobility, explosion of digital traffic, and advent of convergence
network technologies added more dynamism in the idea of NGNs. In fact, facilitating con-
vergence of networks and convergence of various types of services is a significant objective of
NGN
Advances in communication and networking technologies are rapidly making ubiq-
uitous network connectivity a reality. Wireless networks are indispensable for
supporting such access anywhere and at any time. Among various types of wire-
less networks, multihop wireless networks (MWNs) have been attracting increasing
attention for decades due to its broad civilian and military applications. Basically,
a MWN is a network of nodes connected by wireless communication links. Due
to the limited transmission range of the radio, many pairs of nodes in MWNs may
not be able to communicate directly, hence they need other intermediate nodes to
forward packets for them. Routing in such networks is an important issue and it
poses great challenges.
The telecommunications industry has seen a rapid boost within the last decade. New realities
and visions of functionalities in various telecommunications networks have brought forward the
concept of next-generation networks (NGNs). The competitions among operators for support-
ing various services, lowering of the cost of having mobile and cellular phones and smartphones,
increasing demand for general mobility, explosion of digital traffic, and advent of convergence
network technologies added more dynamism in the idea of NGNs. In fact, facilitating con-
vergence of networks and convergence of various types of services is a significant objective of
NGNs.
his research aims at creating broadband tunable, fully integrated filters for the application of
cognitive radio and signal classification receivers. The approach under study is the N-path filter
technique which is capable of translating a baseband impedance to a reference frequency creating
a tunable filter. The traditional N-path filter suffers from fundamental architectural limitations,
namely : a trade-off between insertion loss and out-of-band rejection, reference clock feed-
through, and jammer power handling limitations. In the first approach, the fundamental trade-
off of the traditional N-path filter between insertion loss and out-of-band rejection is improved by
a transmission line (T-line) N-path filter technique.
This paper presents a Hidden Markov Model (HMM)-based speech
enhancement method, aiming at reducing non-stationary noise from speech
signals. The system is based on the assumption that the speech and the noise
are additive and uncorrelated. Cepstral features are used to extract statistical
information from both the speech and the noise. A-priori statistical
information is collected from long training sequences into ergodic hidden
Markov models. Given the ergodic models for the speech and the noise, a
compensated speech-noise model is created by means of parallel model
combination, using a log-normal approximation. During the compensation, the
mean of every mixture in the speech and noise model is stored. The stored
means are then used in the enhancement process to create the most likely
speech and noise power spectral distributions using the forward algorithm
combined with mixture probability. The distributions are used to generate a
Wiener filter for every observation. The paper includes a performance
evaluation of the speech enhancer for stationary as well as non-stationary
noise environment.
A wireless ad-hoc network is a wireless network deployed without any infrastructure. In
such a network, there is no access point or wireless router to forward messages among the
computing devices. Instead, these devices depend on the ad-hoc mode of their wireless net‐
work interface cards to communicate with each other. If the nodes are within the transmis‐
sion range of the wireless signal, they can send messages to each other directly. Otherwise,
the nodes in between will forward the messages for them. Thus, each node is both an end
system and a router simultaneously.
In the field of electricity, electrostatics, and circuit theory, there are many discoveries and
accomplishments that have lead to the foundation of the field of electrostatic discharge
(ESD) phenomenon. Below is a chronological list of key events that moved the field of
electrostatics forward:
RFID is at a critical price point that could enable its large-scale adoption.
What strengths are pushing it forward? What technical challenges and
privacy concerns must we still address?
With the continued growth in the world's population, there is a need to ensure availability of
enough food to feed everyone. Advances in science and technology have helped not only to
increase food production, but also to reduce food wastage. However, the latter has the
potential to be improved to a significant extent through appropriate matching of supply and
demand, and with proper handling during storage and transit. Given the amount of food
wastage that occurs after a food item leaves the “farm” on its way to the “fork,” and the
availability of means to reduce such wastage, there really is no excuse for feigned ignorance.
ABSTRACTThe flyback power stage is a popular choice for single and multiple output dc-to-dc converters at powerlevels of 150 Watts or less. Without the output inductor required in buck derived topologies, such as theforward or push-pull converter, the component count and cost are reduced. This application note will reviewthe design procedure for the power stage and control electronics of a flyback converter. In these isolatedconverters, the error signal from the secondary still needs to cross the isolation boundary to achieveregulation. By using the UC3965 Precision Reference with Low Offset Error Amplifier on the secondaryside to drive an optocoupler and the UCC3809 Economy Primary Side Controller on the primary side, asimple and low cost 50 Watt isolated power supply is realized.
