Abstract: This paper presents a method for obtaining the
desired reference current for Voltage Source Converter (VSC) of the Shunt Active Power Filter (SAPF) using Synchronous Reference Frame Theory. The method relies on the performance of the Proportional-Integral (PI) controller for
obtaining the best control performance of the SAPF. To
improve the performance of the PI controller, the feedback
path to the integral term is introduced to compensate the
winding up phenomenon due to integrator. Using Reference
Frame Transformation, reference signals are transformed from
a - b - c stationery frame to 0 - d - q rotating frame.
Using the PI controller, the reference signals in the 0 - d - q rotating frame are controlled to get the desired reference signals for the Pulse Width Modulation. The synchronizer, the Phase Locked Loop (PLL) with PI filter is used for
synchronization, with much emphasis on minimizing delays. The system performance is examined with Shunt Active Power Filter simulation model.
Abstract: In our modern society electricity is vital to our health,
safety, comfort and well-being. While our daily use of electricity is
often taken for granted, public concern has arisen about potential
adverse health effects from electric and magnetic – electromagnetic –
fields (EMFs) produced by our use of electricity.
This paper aims to compare between the measured magnetic field
values and the simulated models for the indoor medium to low
voltage (MV/LV) distribution substations.
To calculate the magnetic flux density in the substations,
interactive software SUBCALC is used which is based on closed
form solution of the Biot-Savart law with 3D conductor model.
The comparison between the measured values and the simulated
models was acceptable. However there were some discrepancies, as
expected, may be due to the current variation during measurements.
Abstract: Business Process Management (BPM) helps in optimizing the business processes inside an enterprise. But BPM architecture does not provide any help for extending the enterprise. Modern business environments and rapidly changing technologies are asking for brisk changes in the business processes. Service Oriented Architecture (SOA) can help in enabling the success of enterprise-wide BPM. SOA supports agility in software development that is directly related to achieve loose coupling of interacting software agents. Agility is a premium concern of the current software designing architectures. Together, BPM and SOA provide a perfect combination for enterprise computing. SOA provides the capabilities for services to be combined together and to support and create an agile, flexible enterprise. But there are still many questions to answer; BPM is better or SOA? and what is the future track of BPM and SOA? This paper tries to answer some of these important questions.
Abstract: This paper presents a novel three-phase utility
frequency to high frequency soft switching power conversion circuit
with dual mode pulse width modulation and pulse density modulation
for high power induction heating applications as melting of steel and
non ferrous metals, annealing of metals, surface hardening of steel
and cast iron work pieces and hot water producers, steamers and
super heated steamers. This high frequency power conversion circuit
can operate from three-phase systems to produce high current for
high power induction heating applications under the principles of
ZVS and it can regulate its ac output power from the rated value to a
low power level. A dual mode modulation control scheme based on
high frequency PWM in synchronization with the utility frequency
positive and negative half cycles for the proposed high frequency
conversion circuit and utility frequency pulse density modulation is
produced to extend its soft switching operating range for wide ac
output power regulation. A dual packs heat exchanger assembly is
designed to be used in consumer and industrial fluid pipeline systems
and it is proved to be suitable for the hot water, steam and super
heated steam producers. Experiment and simulation results are given
in this paper to verify the operation principles of the proposed ac
conversion circuit and to evaluate its power regulation and
conversion efficiency. Also, the paper presents a mutual coupling
model of the induction heating load instead of equivalent transformer
circuit model.
Abstract: In the current decade, wireless sensor networks are
emerging as a peculiar multi-disciplinary research area. By this
way, energy efficiency is one of the fundamental research themes
in the design of Medium Access Control (MAC) protocols for
wireless sensor networks. Thus, in order to optimize the energy
consumption in these networks, a variety of MAC protocols are
available in the literature. These schemes were commonly evaluated
under simple network density and a few results are published on
their robustness in realistic network-s size. We, in this paper, provide
an analytical study aiming to highlight the energy waste sources in
wireless sensor networks. Then, we experiment three energy efficient
hybrid CSMA/CA based MAC protocols optimized for wireless
sensor networks: Sensor-MAC (SMAC), Time-out MAC (TMAC)
and Traffic aware Energy Efficient MAC (TEEM). We investigate
these protocols with different network densities in order to discuss
the end-to-end performances of these schemes (i.e. in terms of energy
efficiency, delay and throughput). Through Network Simulator (NS-
2) implementations, we explore the behaviors of these protocols with
respect to the network density. In fact, this study may help the multihops
sensor networks designers to design or select the MAC layer
which matches better their applications aims.
Abstract: Most HWRs currently use natural uranium fuel. Using enriched uranium fuel results in a significant improvement in fuel cycle costs and uranium utilization. On the other hand, reactivity changes of HWRs over the full range of operating conditions from cold shutdown to full power are small. This reduces the required reactivity worth of control devices and minimizes local flux distribution perturbations, minimizing potential problems due to transient local overheating of fuel. Analyzing heavy water effectiveness on neutronic parameters such as enrichment requirements, peaking factor and reactivity is important and should pay attention as primary concepts of a HWR core designing. Two nuclear nuclear reactors of CANDU-type and hexagonal-type reactor cores of 33 fuel assemblies and 19 assemblies in 1.04 P/D have been respectively simulated using MCNP-4C code. Using heavy water and light water as moderator have been compared for achieving less reactivity insertion and enrichment requirements. Two fuel matrixes of (232Th/235U)O2 and (238/235U)O2 have been compared to achieve more economical and safe design. Heavy water not only decreased enrichment needs, but it concluded in negative reactivity insertions during moderator density variations. Thorium oxide fuel assemblies of 2.3% enrichment loaded into the core of heavy water moderator resulted in 0.751 fission to absorption ratio and peaking factor of 1.7 using. Heavy water not only provides negative reactivity insertion during temperature raises which changes moderator density but concluded in 2 to 10 kg reduction of enrichment requirements, depend on geometry type.
Abstract: Currently, a large number of license activities (Early
Site Permits, Combined Operating License, reactor certifications,
etc.), are pending for review before the United States Nuclear
Regulatory Commission (US NRC). Much of the senior staff at the
NRC is now committed to these review and licensing actions. To
address this additional workload, the NRC has recruited a large
number of new Regulatory Staff for dealing with these and other
regulatory actions such as the US Fleet of Research and Test Reactors
(RTRs). These reactors pose unusual demands on Regulatory Staff
since the US Fleet of RTRs, although few (32 Licensed RTRs as of
2010), they represent a broad range of reactor types, operations, and
research and training aspects that nuclear reactor power plants (such
as the 104 LWRs) do not pose. The NRC must inspect and regulate
all these facilities. This paper addresses selected training topics and
regulatory activities providedNRC Inspectors for RTRs.
Abstract: The efficiency of an image watermarking technique depends on the preservation of visually significant information. This is attained by embedding the watermark transparently with the maximum possible strength. The current paper presents an approach for still image digital watermarking in which the watermark embedding process employs the wavelet transform and incorporates Human Visual System (HVS) characteristics. The sensitivity of a human observer to contrast with respect to spatial frequency is described by the Contrast Sensitivity Function (CSF). The strength of the watermark within the decomposition subbands, which occupy an interval on the spatial frequencies, is adjusted according to this sensitivity. Moreover, the watermark embedding process is carried over the subband coefficients that lie on edges where distortions are less noticeable. The experimental evaluation of the proposed method shows very good results in terms of robustness and transparency.
Abstract: Biodiversity crisis is one of the many crises that
started at the turn of the millennia. Concrete form of expression is
still disputed, but there is a relatively high consensus regarding the
high rate of degradation and the urgent need for action. The strategy
of action outlines a strong economic component, together with the
recognition of market mechanisms as the most effective policies to
protect biodiversity. In this context, biodiversity and ecosystem
services are natural assets that play a key role in economic strategies
and technological development to promote development and
prosperity. Developing and strengthening policies for transition to an
economy based on efficient use of resources is the way forward.
To emphasize the co-viability specific to the connection economyecosystem
services, scientific approach aimed on one hand how to
implement policies for nature conservation and on the other hand, the
concepts underlying the economic expression of ecosystem services-
value, in the context of current technology. Following the analysis of
business opportunities associated with changes in ecosystem services
was concluded that development of market mechanisms for nature
conservation is a trend that is increasingly stronger individualized
within recent years. Although there are still many controversial issues
that have already given rise to an obvious bias, international
organizations and national governments have initiated and
implemented in cooperation or independently such mechanisms.
Consequently, they created the conditions for convergence between
private interests and social interests of nature conservation, so there
are opportunities for ongoing business development which leads,
among other things, the positive effects on biodiversity. Finally,
points out that markets fail to quantify the value of most ecosystem
services. Existing price signals reflect at best, only a proportion of the
total amount corresponding provision of food, water or fuel.
Abstract: An adaptive fuzzy PID controller with gain scheduling is proposed in this paper. The structure of the proposed gain scheduled fuzzy PID (GS_FPID) controller consists of both fuzzy PI-like controller and fuzzy PD-like controller. Both of fuzzy PI-like and PD-like controllers are weighted through adaptive gain scheduling, which are also determined by fuzzy logic inference. A modified genetic algorithm called accumulated genetic algorithm is designed to learn the parameters of fuzzy inference system. In order to learn the number of fuzzy rules required for the TSK model, the fuzzy rules are learned in an accumulated way. In other words, the parameters learned in the previous rules are accumulated and updated along with the parameters in the current rule. It will be shown that the proposed GS_FPID controllers learned by the accumulated GA perform well for not only the regular linear systems but also the higher order and time-delayed systems.
Abstract: Currently, most of distance learning courses can only
deliver standard material to students. Students receive course content
passively which leads to the neglect of the goal of education – “to suit
the teaching to the ability of students". Providing appropriate course
content according to students- ability is the main goal of this paper.
Except offering a series of conventional learning services, abundant
information available, and instant message delivery, a complete online
learning environment should be able to distinguish between students-
ability and provide learning courses that best suit their ability.
However, if a distance learning site contains well-designed course
content and design but fails to provide adaptive courses, students will
gradually loss their interests and confidence in learning and result in
ineffective learning or discontinued learning. In this paper, an
intelligent tutoring system is proposed and it consists of several
modules working cooperatively in order to build an adaptive learning
environment for distance education. The operation of the system is
based on the result of Self-Organizing Map (SOM) to divide students
into different groups according to their learning ability and learning
interests and then provide them with suitable course content.
Accordingly, the problem of information overload and internet traffic
problem can be solved because the amount of traffic accessing the
same content is reduced.
Abstract: This paper provides an introduction into the
evolution of information and communication technology and illustrates its usage in the work domain. The paper is sub-divided into two parts. The first part gives an overview over the different
phases of information processing in the work domain. It starts by
charting the past and present usage of computers in work
environments and shows current technological trends, which are likely to influence future business applications. The second part
starts by briefly describing, how the usage of computers changed business processes in the past, and presents first Ambient
Intelligence applications based on identification and localization
information, which are already used in the production and retail sector. Based on current systems and prototype applications, the
paper gives an outlook of how Ambient Intelligence technologies could change business processes in the future.
Abstract: Aggressive scaling of MOS devices requires use of ultra-thin gate oxides to maintain a reasonable short channel effect and to take the advantage of higher density, high speed, lower cost etc. Such thin oxides give rise to high electric fields, resulting in considerable gate tunneling current through gate oxide in nano regime. Consequently, accurate analysis of gate tunneling current is very important especially in context of low power application. In this paper, a simple and efficient analytical model has been developed for channel and source/drain overlap region gate tunneling current through ultra thin gate oxide n-channel MOSFET with inevitable deep submicron effect (DSME).The results obtained have been verified with simulated and reported experimental results for the purpose of validation. It is shown that the calculated tunnel current is well fitted to the measured one over the entire oxide thickness range. The proposed model is suitable enough to be used in circuit simulator due to its simplicity. It is observed that neglecting deep sub-micron effect may lead to large error in the calculated gate tunneling current. It is found that temperature has almost negligible effect on gate tunneling current. It is also reported that gate tunneling current reduces with the increase of gate oxide thickness. The impact of source/drain overlap length is also assessed on gate tunneling current.
Abstract: Harmonic pollution and low power factor in power
systems caused by power converters have been of great concern. To
overcome these problems several converter topologies using
advanced semiconductor devices and control schemes have been
proposed. This investigation is to identify a low cost, small size,
efficient and reliable ac to dc converter to meet the input performance
index of UPS. The performance of single phase and three phase ac to
dc converter along with various control techniques are studied and
compared. The half bridge converter topology with linear current
control is identified as most suitable. It is simple, energy efficient
because of single switch power loss and transformer-less operation of
UPS. The results are validated practically using a prototype built
using IGBT and analog controller. The performance for both single
and three-phase system is verified. Digital implementation of closed
loop control achieves higher reliability. Its cost largely depends on
chosen bit precision. The minimal bit precision for optimum
converter performance is identified as 16-bit with fixed-point
operation. From the investigation and practical implementation it is
concluded that half bridge ac – dc converter along with digital linear
controller meets the performance index of UPS for single and three
phase systems.
Abstract: Chikungunya virus (CHICKV) is an arboviruses belonging to family Tagoviridae and is transmitted to human through by mosquito (Aedes aegypti and Aedes albopictus) bite. A large outbreak of chikungunya has been reported in India between 2006 and 2007, along with several other countries from South-East Asia and for the first time in Europe. It was for the first time that the CHICKV outbreak has been reported with mortality from Reunion Island and increased mortality from Asian countries. CHICKV affects all age groups, and currently there are no specific drugs or vaccine to cure the disease. The need of antiviral agents for the treatment of CHICKV infection and the success of virtual screening against many therapeutically valuable targets led us to carry out the structure based drug design against Chikungunya nSP2 protease (PDB: 3TRK). Highthroughput virtual screening of publicly available databases, ZINC12 and BindingDB, has been carried out using the Openeye tools and Schrodinger LLC software packages. Openeye Filter program has been used to filter the database and the filtered outputs were docked using HTVS protocol implemented in GLIDE package of Schrodinger LLC. The top HITS were further used for enriching the similar molecules from the database through vROCS; a shape based screening protocol implemented in Openeye. The approach adopted has provided different scaffolds as HITS against CHICKV protease. Three scaffolds: Indole, Pyrazole and Sulphone derivatives were selected based on the docking score and synthetic feasibility. Derivatives of Pyrazole were synthesized and submitted for antiviral screening against CHICKV.
Abstract: Today-s healthcare industries had become more
patient-centric than profession-centric, from which the issues of quality of healthcare and the patient safety are the major concerns in the modern healthcare facilities. An unplanned extubation (UE) may
be detrimental to the patient-s life, and thus is one of the major indexes
of patient safety and healthcare quality. A high UE rate not only
defeated the healthcare quality as well as the patient safety policy but
also the nurses- morality, and job satisfaction. The UE problem in a psychiatric hospital is unique and may be a tough challenge for the
healthcare professionals for the patients were mostly lacking communication capabilities. We reported with this essay a particular
project that was organized to reduce the UE rate from the current 2.3%
to a lower and satisfactory level in the long-term care units of a psychiatric hospital. The project was conducted between March 1st,
2011 and August 31st, 2011. Based on the error information gathered
from varied units of the hospital, the team analyzed the root causes
with possible solutions proposed to the meetings. Four solutions were
then concluded with consensus and launched to the units in question.
The UE rate was now reduced to a level of 0.17%. Experience from
this project, the procedure and the tools adopted would be good reference to other hospitals.
Abstract: Green Roofs offers numerous advantages, including lowering ambient temperature, which is of increasing interest due to global warming concerns. However, there are technical problems pertaining to waterproofing to be resolved. Currently, the only recognized green roof waterproofing test is the German standard FLL. This paper examines the potential of replicating the test in tropical climate and reducing the test duration by using pre-grown plants. A three year old sample and a new setup were used for this experimental study. The new setup was prepared with close reference to the FLL standards and was compared against the three year old sample. Results showed that the waterproofing membrane was damaged by plant roots in both setups. Joints integrity was also challenged.
Abstract: The growing outsourcing of logistics services
resulting from the ongoing current in firms of costs
reduction/increased efficiency means that it is becoming more and
more important for the companies doing the outsourcing to carry out
a proper evaluation.
The multiple definitions and measures of logistics service
performance found in research on the topic create a certain degree of
confusion and do not clear the way towards the proper measurement
of their performance. Do a model and a specific set of indicators exist
that can be considered appropriate for measuring the performance of
logistics services outsourcing in industrial environments? Are said
indicators in keeping with the objectives pursued by outsourcing? We
aim to answer these and other research questions in the study we have
initiated in the field within the framework of the international High
Performance Manufacturing (HPM) project of which this paper
forms part.
As the first stage of this research, this paper reviews articles
dealing with the topic published in the last 15 years with the aim of
detecting the models most used to make this measurement and
determining which performance indicators are proposed as part of
said models and which are most used. The first steps are also taken in
determining whether these indicators, financial and operational, cover
the aims that are being pursued when outsourcing logistics services.
The findings show there is a wide variety of both models and
indicators used. This would seem to testify to the need to continue
with our research in order to try to propose a model and a set of
indicators for measuring the performance of logistics services
outsourcing in industrial environments.
Abstract: This paper presents a simple approach for load
flow analysis of a radial distribution network. The proposed
approach utilizes forward and backward sweep algorithm
based on Kirchoff-s current law (KCL) and Kirchoff-s voltage
law (KVL) for evaluating the node voltages iteratively. In this
approach, computation of branch current depends only on the
current injected at the neighbouring node and the current in
the adjacent branch. This approach starts from the end nodes
of sub lateral line, lateral line and main line and moves
towards the root node during branch current computation. The
node voltage evaluation begins from the root node and moves
towards the nodes located at the far end of the main, lateral
and sub lateral lines. The proposed approach has been tested
using four radial distribution systems of different size and
configuration and found to be computationally efficient.
Abstract: In this paper, an Arabic letter recognition system based on Artificial Neural Networks (ANNs) and statistical analysis for feature extraction is presented. The ANN is trained using the Least Mean Squares (LMS) algorithm. In the proposed system, each typed Arabic letter is represented by a matrix of binary numbers that are used as input to a simple feature extraction system whose output, in addition to the input matrix, are fed to an ANN. Simulation results are provided and show that the proposed system always produces a lower Mean Squared Error (MSE) and higher success rates than the current ANN solutions.