Abstract: Sensor relocation is to repair coverage holes caused by node failures. One way to repair coverage holes is to find redundant nodes to replace faulty nodes. Most researches took a long time to find redundant nodes since they randomly scattered redundant nodes around the sensing field. To record the precise position of sensor nodes, most researches assumed that GPS was installed in sensor nodes. However, high costs and power-consumptions of GPS are heavy burdens for sensor nodes. Thus, we propose a fast sensor relocation algorithm to arrange redundant nodes to form redundant walls without GPS. Redundant walls are constructed in the position where the average distance to each sensor node is the shortest. Redundant walls can guide sensor nodes to find redundant nodes in the minimum time. Simulation results show that our algorithm can find the proper redundant node in the minimum time and reduce the relocation time with low message complexity.
Abstract: This paper presents the design and analysis of a parallel
connected inverter configuration of. The configuration consists of
parallel connected three-phase dc/ac inverter. Series resistors added
to the inverter output to maintain same current in each inverter of the
two parallel inverters, and to reduce the circulating current in the
parallel inverters to the minimum. High frequency third harmonic
injection PWM (THIPWM) employed to reduce the total harmonic
distortion and to make maximum use of the voltage source. DSP was
used to generate the THIPWM and the control algorithm for the
converter. Selected experimental results have been shown to validate
the proposed system.
Abstract: Microparticles carrier systems made from naturally occurring polymers based on chitosan/casein system appears to be a promising carrier for the sustained release of orally and parenteral administered drugs. In the current study we followed a microencapsulation technique based aqueous coacervation method to prepare chitosan/casein microparticles of compositions 1:1, 1:2 and 1:5 incorporated with chloramphenicol. Glutaraldehyde was used as a chemical cross-linking agent. The microparticles were prepared by aerosol method and studied by optical microscopy, infrared spectroscopy, thermo gravimetric analysis, swelling studies and drug release studies at various pH. The percentage swelling of the polymers are found to be in the order pH 4 > pH 10 > pH 7 and the increase in casein composition decrease the swelling percentage. The drug release studies also follow the above order.
Abstract: The desulfurization of coal using biological methods is an emerging technology. The biodesulfurization process uses the catalytic activity of chemolithotrophic acidpohiles in removing sulfur and pyrite from the coal. The present study was undertaken to examine the potential of Acidithiobacillus ferrooxidans in removing the pyritic sulfur and iron from high iron and sulfur containing US coal. The experiment was undertaken in 10 L batch stirred tank reactor having 10% pulp density of coal. The reactor was operated under mesophilic conditions and aerobic conditions were maintained by sparging the air into the reactor. After 35 days of experiment, about 64% of pyrite and 21% of pyritic sulfur was removed from the coal. The findings of the present study indicate that the biodesulfurization process does have potential in treating the high pyrite and sulfur containing coal. A good mass balance was also obtained with net loss of about 5% showing its feasibility for large scale application.
Abstract: This paper presents a methodology to harvest the kinetic energy of the raindrops using piezoelectric devices. In the study 1m×1m PVDF (Polyvinylidene fluoride) piezoelectric membrane, which is fixed by the four edges, is considered for the numerical simulation on deformation of the membrane due to the impact of the raindrops. Then according to the drop size of the rain, the simulation is performed classifying the rainfall types into three categories as light stratiform rain, moderate stratiform rain and heavy thundershower. The impact force of the raindrop is dependent on the terminal velocity of the raindrop, which is a function of raindrop diameter. The results were then analyzed to calculate the harvestable energy from the deformation of the piezoelectric membrane.
Abstract: The main objective of Automatic Generation Control (AGC) is to balance the total system generation against system load losses so that the desired frequency and power interchange with neighboring systems is maintained. Any mismatch between generation and demand causes the system frequency to deviate from its nominal value. Thus high frequency deviation may lead to system collapse. This necessitates a very fast and accurate controller to maintain the nominal system frequency. This paper deals with a novel approach of artificial intelligence (AI) technique called Hybrid Neuro-Fuzzy (HNF) approach for an (AGC). The advantage of this controller is that it can handle the non-linearities at the same time it is faster than other conventional controllers. The effectiveness of the proposed controller in increasing the damping of local and inter area modes of oscillation is demonstrated in a two area interconnected power system. The result shows that intelligent controller is having improved dynamic response and at the same time faster than conventional controller.
Abstract: The well known NP-complete problem of the Traveling Salesman Problem (TSP) is coded in genetic form. A software system is proposed to determine the optimum route for a Traveling Salesman Problem using Genetic Algorithm technique. The system starts from a matrix of the calculated Euclidean distances between the cities to be visited by the traveling salesman and a randomly chosen city order as the initial population. Then new generations are then created repeatedly until the proper path is reached upon reaching a stopping criterion. This search is guided by a solution evaluation function.
Abstract: In this study, control performance of a smart base
isolation system consisting of a friction pendulum system (FPS) and a
magnetorheological (MR) damper has been investigated. A fuzzy
logic controller (FLC) is used to modulate the MR damper so as to
minimize structural acceleration while maintaining acceptable base
displacement levels. To this end, a multi-objective optimization
scheme is used to optimize parameters of membership functions and
find appropriate fuzzy rules. To demonstrate effectiveness of the
proposed multi-objective genetic algorithm for FLC, a numerical
study of a smart base isolation system is conducted using several
historical earthquakes. It is shown that the proposed method can find
optimal fuzzy rules and that the optimized FLC outperforms not only a
passive control strategy but also a human-designed FLC and a
conventional semi-active control algorithm.
Abstract: Network on Chip (NoC) has emerged as a promising
on chip communication infrastructure. Three Dimensional Integrate
Circuit (3D IC) provides small interconnection length between layers
and the interconnect scalability in the third dimension, which can
further improve the performance of NoC. Therefore, in this paper,
a hierarchical cluster-based interconnect architecture is merged with
the 3D IC. This interconnect architecture significantly reduces the
number of long wires. Since this architecture only has approximately
a quarter of routers in 3D mesh-based architecture, the average
number of hops is smaller, which leads to lower latency and higher
throughput. Moreover, smaller number of routers decreases the area
overhead. Meanwhile, some dual links are inserted into the bottlenecks
of communication to improve the performance of NoC.
Simulation results demonstrate our theoretical analysis and show the
advantages of our proposed architecture in latency, throughput and
area, when compared with 3D mesh-based architecture.
Abstract: Coordinated supply chain represents major challenges
for the different actors involved in it, because each agent responds to
individual interests. The paper presents a framework with the
reviewed literature regarding the system's decision structure and
nature of demand. Later, it characterizes an agri food supply chain in
the Central Region of Colombia, it responds to a decentralized
distribution system and a stochastic demand. Finally, the paper
recommends coordinating the chain based on shared information, and
mechanisms for each agent, as VMI (vendor-managed inventory)
strategy for farmer-buyer relationship, information system for
farmers and contracts for transportation service providers.
Abstract: Considering payload, reliability, security and operational lifetime as major constraints in transmission of images we put forward in this paper a steganographic technique implemented at the physical layer. We suggest transmission of Halftoned images (payload constraint) in wireless sensor networks to reduce the amount of transmitted data. For low power and interference limited applications Turbo codes provide suitable reliability. Ensuring security is one of the highest priorities in many sensor networks. The Turbo Code structure apart from providing forward error correction can be utilized to provide for encryption. We first consider the Halftoned image and then the method of embedding a block of data (called secret) in this Halftoned image during the turbo encoding process is presented. The small modifications required at the turbo decoder end to extract the embedded data are presented next. The implementation complexity and the degradation of the BER (bit error rate) in the Turbo based stego system are analyzed. Using some of the entropy based crypt analytic techniques we show that the strength of our Turbo based stego system approaches that found in the OTPs (one time pad).
Abstract: The article deals with numerical investigation of axisymmetric
subsonic air to air ejector. An analysis of flow and mixing
processes in cylindrical mixing chamber are made. Several modes
with different velocity and ejection ratio are presented. The mixing
processes are described and differences between flow in the initial
region of mixing and the main region of mixing are described. The
lengths of both regions are evaluated. Transition point and point
where the mixing processes are finished are identified. It was found
that the length of the initial region of mixing is strongly dependent on
the velocity ratio, while the length of the main region of mixing is
dependent on velocity ratio only slightly.
Abstract: Many single or multispan arch bridges are
strengthened with the addition of some kind of structural support
between adjacent arches of multispan or beside the arch barrel of a
single span to increase the strength of the overall structure. It was
traditionally formed by either placing loose rubble masonry blocks
between the arches and beside the arches or using mortar or concrete
to construct a more substantial structural bond between the spans. On
the other hand backing materials are present in some existing bridges.
Existing arch assessment procedures generally ignore the effects of
backing materials. In this paper an investigation of the effects of
backing on ratings for masonry arch bridges is carried out. It is
observed that increasing the overall lateral stability of the arch
system through the inclusion of structural backing results in an
enhanced failure load by reducing the likelihood of any tension
occurring at the top of the arch.
Abstract: In a complex project environment, project teams face
multi-dimensional communication problems that can ultimately lead
to project breakdown. Team Performance varies in Face-to-Face
(FTF) environment versus groups working remotely in a computermediated
communication (CMC) environment. A brief review of the
Input_Process_Output model suggested by James E. Driskell, Paul H.
Radtke and Eduardo Salas in “Virtual Teams: Effects of
Technological Mediation on Team Performance (2003)", has been
done to develop the basis of this research. This model theoretically
analyzes the effects of technological mediation on team processes,
such as, cohesiveness, status and authority relations, counternormative
behavior and communication. An empirical study
described in this paper has been undertaken to test the
“cohesiveness" of diverse project teams in a multi-national
organization. This study uses both quantitative and qualitative
techniques for data gathering and analysis. These techniques include
interviews, questionnaires for data collection and graphical data
representation for analyzing the collected data. Computer-mediated
technology may impact team performance because of difference in
cohesiveness among teams and this difference may be moderated by
factors, such as, the type of communication environment, the type of
task and the temporal context of the team. Based on the reviewed
model, sets of hypotheses are devised and tested. This research,
reports on a study that compared team cohesiveness among virtual
teams using CMC and non-CMC communication mediums. The
findings suggest that CMC can help virtual teams increase team
cohesiveness among their members, making CMC an effective
medium for increasing productivity and team performance.
Abstract: Based on the fuzzy set theory this work develops two
adaptations of iterative methods that solve mathematical programming
problems with uncertainties in the objective function and in
the set of constraints. The first one uses the approach proposed by
Zimmermann to fuzzy linear programming problems as a basis and
the second one obtains cut levels and later maximizes the membership
function of fuzzy decision making using the bound search method.
We outline similarities between the two iterative methods studied.
Selected examples from the literature are presented to validate the
efficiency of the methods addressed.
Abstract: Powder of La0.6Sr0.4CoO3-α (LSCO) was synthesized
by a combined citrate-EDTA method. The as-synthesized LSCO
powder was calcined, respectively at temperatures of 800, 900 and
1000 °C with different heating/cooling rates which are 2, 5, 10 and
15 °C min-1. The effects of heat treatments on the phase formation of
perovskite phase of LSCO were investigated by powder X-ray
diffraction (XRD). The XRD patterns revealed that the rate of
5 °C min-1 is the optimum heating/cooling rate to obtain a single
perovskite phase of LSCO with calcination temperature of 800 °C.
This result was confirmed by a thermogravimetric analysis (TGA) as
it showed a complete decomposition of intermediate compounds to
form oxide material was also observed at 800 °C.
Abstract: New design of a grid for preparation of high density
granules with enhanced mechanical strength by granulation of
dispersed materials is suggested.
A method for hydrodynamic dimensioning of the grid depending
on granulation conditions, hydrodynamic regime of the operation,
dispersity and physicochemical characteristics of the materials to be
granulated was suggested.
The aim of the grid design is to solve the problems arising by the
granulation of disperse materials.
Abstract: This paper features the kinematic modelling of a 5-axis stationary articulated robot arm which is used for doing successful robotic manipulation task in its workspace. To start with, a 5-axes articulated robot was designed entirely from scratch and from indigenous components and a brief kinematic modelling was performed and using this kinematic model, the pick and place task was performed successfully in the work space of the robot. A user friendly GUI was developed in C++ language which was used to perform the successful robotic manipulation task using the developed mathematical kinematic model. This developed kinematic model also incorporates the obstacle avoiding algorithms also during the pick and place operation.
Abstract: A robust wheel slip controller for electric vehicles is
introduced. The proposed wheel slip controller exploits the dynamics
of electric traction drives and conventional hydraulic brakes for
achieving maximum energy efficiency and driving safety. Due to
the control of single wheel traction motors in combination with a
hydraulic braking system, it can be shown, that energy recuperation
and vehicle stability control can be realized simultaneously. The
derivation of a sliding mode wheel slip controller accessing two
drivetrain actuators is outlined and a comparison to a conventionally
braked vehicle is shown by means of simulation.