Abstract: Nowadays, in most radiotherapy departments, the commercial treatment planning systems (TPS) used to calculate dose distributions needs to be verified; therefore, quick, easy-to-use and low cost dose distribution algorithms are desirable to test and verify the performance of the TPS. In this paper, we put forth an analytical method to calculate the phantom scatter contribution and depth dose on the central axis based on the equivalent square concept. Then, this method was generalized to calculate the profiles at any depth and for several field shapes regular or irregular fields under symmetry and asymmetry photon beam conditions. Varian 2100 C/D and Siemens Primus Plus Linacs with 6 and 18 MV photon beam were used for irradiations. Percentage depth doses (PDDs) were measured for a large number of square fields for both energies, and for 45º wedges which were employed to obtain the profiles in any depth. To assess the accuracy of the calculated profiles, several profile measurements were carried out for some treatment fields. The calculated and measured profiles were compared by gamma-index calculation. All γ–index calculations were based on a 3% dose criterion and a 3 mm dose-to-agreement (DTA) acceptance criterion. The γ values were less than 1 at most points. However, the maximum γ observed was about 1.10 in the penumbra region in most fields and in the central area for the asymmetric fields. This analytical approach provides a generally quick and fairly accurate algorithm to calculate dose distribution for some treatment fields in conventional radiotherapy.
Abstract: The purpose of this paper is to simulate the production process of a metal stamping industry and to evaluate the utilization of the production line by using ARENA simulation software. The process time and the standard time for each process of the production line is obtained from data given by the company management. Other data are collected through direct observation of the line. There are three work stations performing ten different types of processes in order to produce a single product type. Arena simulation model is then developed based on the collected data. Verification and validation are done to the Arena model, and finally the result of Arena simulation can be analyzed. It is found that utilization at each workstation will increase if batch size is increased although throughput rate remains/is kept constant. This study is very useful for the company because the company needs to improve the efficiency and utilization of its production lines.
Abstract: This paper presents device simulations on the vertical silicon nanowire tunneling FET (VSiNW TFET). Simulations show that a narrow nanowire and thin gate oxide is required for good performance, which is expected even for conventional MOSFETs. The gate length also needs to be more than the nanowire diameter to prevent short channel effects. An effect more unique to TFET is the need for abrupt source to channel junction, which is shown to improve the performance. The ambipolar effect suppression by reducing drain doping concentration is also explored and shown to have little or no effect on performance.
Abstract: This paper outlines the application of Knowledge Management (KM) principles in the context of Educational institutions. The paper caters to the needs of the engineering institutions for imparting quality education by delineating the instruction delivery process in a highly structured, controlled and quantified manner. This is done using a software tool EDULOGIC+. The central idea has been based on the engineering education pattern in Indian Universities/ Institutions. The data, contents and results produced over contiguous years build the necessary ground for managing the related accumulated knowledge. Application of KM has been explained using certain examples of data analysis and knowledge extraction.
Abstract: Certain sciences such as physics, chemistry or biology,
have a strong computational aspect and use computing infrastructures
to advance their scientific goals. Often, high performance and/or high
throughput computing infrastructures such as clusters and computational
Grids are applied to satisfy computational needs. In addition,
these sciences are sometimes characterised by scientific collaborations
requiring resource sharing which is typically provided by Grid
approaches. In this article, I discuss Grid computing approaches in
High Energy Physics as well as in bioinformatics and highlight some
of my experience in both scientific domains.
Abstract: One of the major features of hypermedia learning is its non-linear structure, allowing learners, the opportunity of flexible navigation to accommodate their own needs. Nevertheless, such flexibility can also cause problems such as insufficient navigation and disorientation for some learners, especially those with Field Dependent cognitive styles. As a result students learning performance can be deteriorated and in turn, they can have negative attitudes with hypermedia learning systems. It was suggested that visual elements can be used to compensate dilemmas. However, it is unclear whether these visual elements improve their learning or whether problems still exist. The aim of this study is to investigate the effect of students cognitive styles and visual elements on students learning performance and attitudes in hypermedia learning environment. Cognitive Style Analysis (CSA), Learning outcome in terms of pre and post-test, practical task, and Attitude Questionnaire (AQ) were administered to a sample of 60 university students. The findings revealed that FD students preformed equally to those of FI. Also, FD students experienced more disorientation in the hypermedia learning system where they depend a lot on the visual elements for navigation and orientation purposes. Furthermore, they had more positive attitudes towards the visual elements which escape them from experiencing navigation and disorientation dilemmas. In contrast, FI students were more comfortable, did not get disturbed or did not need some of the visual elements in the hypermedia learning system.
Abstract: Over the early years of the 21st century, cities
throughout the Middle East, particularly in the Gulf region have
expanded more rapidly than ever before. Given the presence of a
large volume of high-rise buildings allover the region, the local
authority aims to set a new standard for sustainable development;
with an integrated approach to maintain a balance between economy,
quality, environmental protection and safety of life. In the very near
future, as mandatory requirements, sustainability will be the criteria
that should be included in all building projects. It is well known in
the building sustainability topics that structural design engineers do
not have a key role in this matter. In addition, the LEED (Leadership
in Energy and Environmental Design) has looked almost exclusively
on the environmental components and materials specifications. The
objective of this paper is to focus and establish groundwork for
sustainability techniques and applications related to the RC high-rise
buildings design, from the structural point of view. A set of
recommendations related to local conditions, structural modeling and
analysis is given, and some helpful suggestions for structural design
team work are addressed. This paper attempts to help structural
engineers in identifying the building sustainability design, in order to
meet local needs and achieve alternative solutions at an early stage of
project design.
Abstract: The use of neural networks for recognition application is generally constrained by their inherent parameters inflexibility after the training phase. This means no adaptation is accommodated for input variations that have any influence on the network parameters. Attempts were made in this work to design a neural network that includes an additional mechanism that adjusts the threshold values according to the input pattern variations. The new approach is based on splitting the whole network into two subnets; main traditional net and a supportive net. The first deals with the required output of trained patterns with predefined settings, while the second tolerates output generation dynamically with tuning capability for any newly applied input. This tuning comes in the form of an adjustment to the threshold values. Two levels of supportive net were studied; one implements an extended additional layer with adjustable neuronal threshold setting mechanism, while the second implements an auxiliary net with traditional architecture performs dynamic adjustment to the threshold value of the main net that is constructed in dual-layer architecture. Experiment results and analysis of the proposed designs have given quite satisfactory conducts. The supportive layer approach achieved over 90% recognition rate, while the multiple network technique shows more effective and acceptable level of recognition. However, this is achieved at the price of network complexity and computation time. Recognition generalization may be also improved by accommodating capabilities involving all the innate structures in conjugation with Intelligence abilities with the needs of further advanced learning phases.
Abstract: The most important subtype of non-Hodgkin-s
lymphoma is the Diffuse Large B-Cell Lymphoma. Approximately
40% of the patients suffering from it respond well to therapy,
whereas the remainder needs a more aggressive treatment, in order to
better their chances of survival. Data Mining techniques have helped
to identify the class of the lymphoma in an efficient manner. Despite
that, thousands of genes should be processed to obtain the results.
This paper presents a comparison of the use of various attribute
selection methods aiming to reduce the number of genes to be
searched, looking for a more effective procedure as a whole.
Abstract: In deregulated operating regime power system security is an issue that needs due thoughtfulness from researchers in the horizon of unbundling of generation and transmission. Electric power systems are exposed to various contingencies. Network contingencies often contribute to overloading of branches, violation of voltages and also leading to problems of security/stability. To maintain the security of the systems, it is desirable to estimate the effect of contingencies and pertinent control measurement can be taken on to improve the system security. This paper presents the application of particle swarm optimization algorithm to find the optimal location of multi type FACTS devices in a power system in order to eliminate or alleviate the line over loads. The optimizations are performed on the parameters, namely the location of the devices, their types, their settings and installation cost of FACTS devices for single and multiple contingencies. TCSC, SVC and UPFC are considered and modeled for steady state analysis. The selection of UPFC and TCSC suitable location uses the criteria on the basis of improved system security. The effectiveness of the proposed method is tested for IEEE 6 bus and IEEE 30 bus test systems.
Abstract: This study aims to assess the potential of solar energy technology for improving access to water and hence the livelihood strategies of rural communities in Baja California Sur, Mexico. It focuses on livestock ranches and photovoltaic water-pumptechnology as well as other water extraction methods. The methodology used are the Sustainable Livelihoods and the Appropriate Technology approaches. A household survey was applied in June of 2006 to 32 ranches in the municipality, of which 22 used PV pumps; and semi-structured interviews were conducted. Findings indicate that solar pumps have in fact helped people improve their quality of life by allowing them to pursue a different livelihood strategy and that improved access to water -not necessarily as more water but as less effort to extract and collect it- does not automatically imply overexploitation of the resource; consumption is based on basic needs as well as on storage and pumping capacity. Justification for such systems lies in the avoidance of logistical problems associated to fossil fuels, PV pumps proved to be the most beneficial when substituting gasoline or diesel equipment but of dubious advantage if intended to replace wind or gravity systems. Solar water pumping technology-s main obstacle to dissemination are high investment and repairs costs and it is therefore not suitable for all cases even when insolation rates and water availability are adequate. In cases where affordability is not an obstacle it has become an important asset that contributes –by means of reduced expenses, less effort and saved time- to the improvement of livestock, the main livelihood provider for these ranches.
Abstract: Continuously variable transmission (CVT) is a type of
automatic transmission that can change the gear ratio to any arbitrary
setting within the limits. The most common type of CVT operates on
a pulley system that allows an infinite variability between highest and
lowest gears with no discrete steps. However, the current CVT
system with hydraulic actuation method suffers from the power loss.
It needs continuous force for the pulley to clamp the belt and hold the
torque resulting in large amount of energy consumption. This study
focused on the development of an electromechanical actuated control
CVT to eliminate the problem that faced by the existing CVT. It is
conducted with several steps; computing and selecting the
appropriate sizing for stroke length, lead screw system and etc. From
the visual observation it was found that the CVT system of this
research is satisfactory.
Abstract: In this paper, we study statistical multiplexing of VBR
video in ATM networks. ATM promises to provide high speed realtime
multi-point to central video transmission for telemedicine
applications in rural hospitals and in emergency medical services.
Video coders are known to produce variable bit rate (VBR) signals
and the effects of aggregating these VBR signals need to be
determined in order to design a telemedicine network infrastructure
capable of carrying these signals. We first model the VBR video
signal and simulate it using a generic continuous-data autoregressive
(AR) scheme. We carry out the queueing analysis by the Fluid
Approximation Model (FAM) and the Markov Modulated Poisson
Process (MMPP). The study has shown a trade off: multiplexing
VBR signals reduces burstiness and improves resource utilization,
however, the buffer size needs to be increased with an associated
economic cost. We also show that the MMPP model and the Fluid
Approximation model fit best, respectively, the cell region and the
burst region. Therefore, a hybrid MMPP and FAM completely
characterizes the overall performance of the ATM statistical
multiplexer. The ramifications of this technology are clear: speed,
reliability (lower loss rate and jitter), and increased capacity in video
transmission for telemedicine. With migration to full IP-based
networks still a long way to achieving both high speed and high
quality of service, the proposed ATM architecture will remain of
significant use for telemedicine.
Abstract: Increased energy demand and the concern about
environment friendly technology, renewable bio-fuels are better
alternative to petroleum products. In the present study linseed oil was
used as alternative source for diesel engine fuel and the results were
compared with baseline data of neat diesel. Performance parameters
such as brake thermal efficiency (BTE) and brake specific fuel
consumption (BSFC) and emissions parameters such as CO,
unburned hydro carbon (UBHC), NOx, CO2 and exhaust temperature
were compared. BTE of the engine was lower and BSFC was higher
when the engine was fueled with Linseed oil compared to diesel fuel.
Emission characteristics are better than diesel fuel. NOx formation by
using linseed oil during the experiment was lower than diesel fuel.
Linseed oil is non edible oil, so it can be used as an extender of diesel
fuel energy source for small and medium energy needs.
Abstract: Nowadays, keyless entry systems are widely adopted
for vehicle immobilizer systems due to both advantages of security and
convenience. Keyless entry systems could overcome brute-force key
guessing attack, statistics attack and masquerade attack, however,
they can't prevent from thieves stealing behavior. In this paper, we
proposed a new architecture try to improve the existent flaws. The
integration of the keyless entry system and the fingerprint
identification technology is more suitable to implement on the
portable transponder to achieve higher security needs. We also adopt
and modify AES security protocol for life expectancy and security of
the portable transponder. In addition, the identification of a driver's
fingerprint makes the service of automatic reinstatement of a driver's
preferences become possible. Our design can satisfy not only the three
kinds of previous illegal attacks, but also the stealing situation.
Furthermore, many practical factors, such as costs, life expectancy and
performance, have been well considered in the design of portable
transponder.
Abstract: In this study, the performance of a high-frequency arc
welding machine including a two-switch inverter is analyzed. The
control of the system is achieved using two different control
techniques i- fuzzy logic control (FLC) ii- state space averaging
based sliding control. Fuzzy logic control does not need accurate
mathematical model of a plant and can be used in nonlinear
applications. The second method needs the mathematical model of
the system. In this method the state space equations of the system are
derived for two different “on" and “off" states of the switches. The
derived state equations are combined with the sliding control rule
considering the duty-cycle of the converter. The performance of the
system is analyzed by simulating the system using SIMULINK tool
box of MATLAB. The simulation results show that fuzzy logic
controller is more robust and less sensitive to parameter variations.
Abstract: An experiment was performed in the south of
Morocco in order to evaluate the effect of deficit irrigation by treated
wastewater on chickpea production. We applied six irrigation
treatments on a local variety of chickpea by supplying alternatively
50 or 100% of ETm in a completely randomized design.
We found a highly significant difference between treatments in
terms of biomass production. Drought stress during the vegetative
period showed highest yield with 6.5 t/ha which was more than the
yield obtained for the control (4.9 t/ha). The optimal crop stage in
which deficit irrigation can be applied is the vegetative growth stage,
as the crop has a chance to develop its root system, to be able to
cover the plant needs for water and nutrient supply during the rest of
cycle, and non stress conditions during the flowering and seed filling
stages allow the plant to optimize its photosynthesis and carbon
translocation, therefore increase its productivity.
Abstract: The primary aim of the e-government applications is
the fast citizen service and the accomplishment of governmental
functions. This paper discusses the knowledge management for egovernment
development in the needs and role. The paper focused
on analyzing the advantages of using knowledge management by
using the existing IT technologies to maximize the government
functions efficiency. The proposed new approach of providing
government services is based on using Knowledge management as a
part of e-government system.
Abstract: In general, reports are a form of representing data in
such way that user gets the information he needs. They can be built in
various ways, from the simplest (“select from") to the most complex
ones (results derived from different sources/tables with complex
formulas applied). Furthermore, rules of calculations could be written
as a program hard code or built in the database to be used by dynamic
code. This paper will introduce two types of reports, defined in the
DB structure. The main goal is to manage calculations in optimal
way, keeping maintenance of reports as simple and smooth as
possible.
Abstract: In recent years, new product development became more and more competitive and globalized, and the designing phase is critical for the product success. The concept of modularity can provide the necessary foundation for organizations to design products that can respond rapidly to market needs. The paper describes data structures and algorithms of intelligent Web-based system for modular design taking into account modules compatibility relationship and given design requirements. The system intelligence is realized by developed algorithms for choice of modules reflecting all system restrictions and requirements. The proposed data structure and algorithms are illustrated by case study of personal computer configuration. The applicability of the proposed approach is tested through a prototype of Web-based system.