Abstract: The InAlGaN alloy has only recently began receiving
serious attention into its growth and application. High quality InGaN
films have led to the development of light emitting diodes (LEDs) and
blue laser diodes (LDs). The quaternary InAlGaN however, represents
a more versatile material since the bandgap and lattice constant can be
independently varied. We report an ultraviolet (UV) quaternary
InAlGaN multi-quantum wells (MQWs) LD study by using the
simulation program of Integrated System Engineering (ISE TCAD).
Advanced physical models of semiconductor properties were used in
order to obtain an optimized structure. The device performance which
is affected by piezoelectric and thermal effects was studied via
drift-diffusion model for carrier transport, optical gain and loss. The
optical performance of the UV LD with different numbers of quantum
wells was numerically investigated. The main peak of the emission
wavelength for double quantum wells (DQWs) was shifted from 358
to 355.8 nm when the forward current was increased. Preliminary
simulated results indicated that better output performance and lower
threshold current could be obtained when the quantum number is four,
with output power of 130 mW and threshold current of 140 mA.
Abstract: The objective of the paper was to understand the use
of an important element of design, namely color in a Semiotic
system. Semiotics is the study of signs and sign processes, it is often
divided into three branches namely (i) Semantics that deals with the
relation between signs and the things to which they refer to mean, (ii)
Syntactics which addresses the relations among signs in formal
structures and (iii) Pragmatics that relates between signs and its
effects on they have on the people who use them to create a plan for
an object or a system referred to as design. Cubism with its versatility
was the key design tool prevalent across the 20th century. In order to
analyze the user's understanding of interaction and appreciation of
color through the movement of Cubism, an exercise was undertaken
in Dept. of Design, IIT Guwahati. This included tasks to design a
composition using color and sign process to the theme 'Between the
Lines' on a given tessellation where the users relate their work to the
world they live in, which in this case was the college campus of IIT
Guwahati. The findings demonstrate impact of the key design
element color on the principles of visual perception based on image
analysis of specific compositions.
Abstract: The Partitioned Global Address Space (PGAS) programming
paradigm offers ease-of-use in expressing parallelism
through a global shared address space while emphasizing performance
by providing locality awareness through the partitioning of
this address space. Therefore, the interest in PGAS programming
languages is growing and many new languages have emerged and
are becoming ubiquitously available on nearly all modern parallel
architectures. Recently, new parallel machines with multiple cores
are designed for targeting high performance applications. Most of the
efforts have gone into benchmarking but there are a few examples of
real high performance applications running on multicore machines.
In this paper, we present and evaluate a parallelization technique
for implementing a local DNA sequence alignment algorithm using
a PGAS based language, UPC (Unified Parallel C) on a chip
multithreading architecture, the UltraSPARC T1.
Abstract: This paper describes a paradigmatic approach to develop architecture of secure systems by describing the requirements from four different points of view: that of the owner, the administrator, the user, and the network. Deriving requirements and developing architecture implies the joint elicitation and describing the problem and the structure of the solution. The view points proposed in this paper are those we consider as requirements towards their contributions as major parties in the design, implementation, usage and maintenance of secure systems. The dramatic growth of the technology of Internet and the applications deployed in World Wide Web have lead to the situation where the security has become a very important concern in the development of secure systems. Many security approaches are currently being used in organizations. In spite of the widespread use of many different security solutions, the security remains a problem. It is argued that the approach that is described in this paper for the development of secure architecture is practical by all means. The models representing these multiple points of view are termed the requirements model (views of owner and administrator) and the operations model (views of user and network). In this paper, this multiple view paradigm is explained by first describing the specific requirements and or characteristics of secure systems (particularly in the domain of networks) and the secure architecture / system development methodology.
Abstract: During signal transmission, the combined effect of the
transmitter filter, the transmission medium, and additive white
Gaussian noise (AWGN) are included in the channel which distort
and add noise to the signal. This causes the well defined signal
constellation to spread causing errors in bit detection. A compact pi
neural network with minimum number of nodes is proposed. The
replacement of summation at each node by multiplication results in
more powerful mapping. The resultant pi network is tested on six
different channels.
Abstract: In this study, a network quality of service (QoS)
evaluation system was proposed. The system used a combination of
fuzzy C-means (FCM) and regression model to analyse and assess the
QoS in a simulated network. Network QoS parameters of multimedia
applications were intelligently analysed by FCM clustering
algorithm. The QoS parameters for each FCM cluster centre were
then inputted to a regression model in order to quantify the overall
QoS. The proposed QoS evaluation system provided valuable
information about the network-s QoS patterns and based on this
information, the overall network-s QoS was effectively quantified.
Abstract: This paper seeks to give a general idea of the universe of project portfolio management, from its multidisciplinary nature, to the many challenges it raises, passing through the different techniques, models and tools used to solve the multiple problems known. It is intended to contribute to the clarification, with great depth, of the impacts and relationships involved in managing the projects- portfolio. It aims at proposing a technique for the project alignment with the organisational strategy, in order to select projects that later on will be considered in the analysis and selection of the portfolio. We consider the development of a methodology for assessing the project alignment index very relevant in the global market scenario. It can help organisations to gain a greater awareness of market dynamics, speed up the decision process and increase its consistency, thus enabling the strategic alignment and the improvement of the organisational performance.
Abstract: The main aims in this research are to study the solid
waste generation in the Faculty of Engineering and Built
Environment in the UKM and at the same time to determine
composition and some of the waste characteristics likewise: moisture
content, density, pH and C/N ratio. For this purpose multiple
campaigns were conducted to collect the wastes produced in all
hostels, faculties, offices and so on, during 24th of February till 2nd
of March 2009, measure and investigate them with regard to both
physical and chemical characteristics leading to highlight the
necessary management policies. Research locations are Faculty of
Engineering and the Canteen nearby that. From the result gained, the
most suitable solid waste management solution will be proposed to
UKM. The average solid waste generation rate in UKM is 203.38
kg/day. The composition of solid waste generated are glass, plastic,
metal, aluminum, organic and inorganic waste and others waste.
From the laboratory result, the average moisture content, density, pH
and C/N ratio values from the solid waste generated are 49.74%,
165.1 kg/m3, 5.3, and 7:1 respectively. Since, the food waste (organic
waste) were the most dominant component, around 62% from the
total waste generated hence, the most suitable solid waste
management solution is composting.
Abstract: In this paper, by using Mawhin-s continuation theorem of coincidence degree theory, we establish the existence of multiple positive periodic solutions of a competitor-competitor-mutualist Lotka-Volterra system with harvesting terms. Finally, an example is given to illustrate our results.
Abstract: In this paper the multi-mode resource-constrained project scheduling problem with discounted cash flows is considered. Minimizing the makespan and maximization the net present value (NPV) are the two common objectives that have been investigated in the literature. We apply one evolutionary algorithm named multiobjective particle swarm optimization (MOPSO) to find Pareto front solutions. We used standard sets of instances from the project scheduling problem library (PSPLIB). The results are computationally compared respect to different metrics taken from the literature on evolutionary multi-objective optimization.
Abstract: power-line networks are promise infrastructure for
broadband services provision to end users. However, the network
performance is affected by stochastic channel changing which is due
to load impedances, number of branches and branched line lengths. It
has been proposed that multi-carrier modulations techniques such as
orthogonal frequency division multiplexing (OFDM), Multi-Carrier
Spread Spectrum (MC-SS), wavelet OFDM can be used in such
environment. This paper investigates the performance of different
indoor topologies of power-line networks that uses MC-SS
modulation scheme.It is observed that when a branch is added in the
link between sending and receiving end of an indoor channel an
average of 2.5dB power loss is found. In additional, when the branch
is added at a node an average of 1dB power loss is found.
Additionally when the terminal impedances of the branch change
from line characteristic impedance to impedance either higher or
lower values the channel performances were tremendously improved.
For example changing terminal load from characteristic impedance
(85 .) to 5 . the signal to noise ratio (SNR) required to attain the
same performances were decreased from 37dB to 24dB respectively.
Also, changing the terminal load from channel characteristic
impedance (85 .) to very higher impedance (1600 .) the SNR
required to maintain the same performances were decreased from
37dB to 23dB. The result concludes that MC-SS performs better
compared with OFDM techniques in all aspects and especially when
the channel is terminated in either higher or lower impedances.
Abstract: This paper explores an application of an adaptive learning mechanism for robots based on the natural immune system. Most of the research carried out so far are based either on the innate or adaptive characteristics of the immune system, we present a combination of these to achieve behavior arbitration wherein a robot learns to detect vulnerable areas of a track and adapts to the required speed over such portions. The test bed comprises of two Lego robots deployed simultaneously on two predefined near concentric tracks with the outer robot capable of helping the inner one when it misaligns. The helper robot works in a damage-control mode by realigning itself to guide the other robot back onto its track. The panic-stricken robot records the conditions under which it was misaligned and learns to detect and adapt under similar conditions thereby making the overall system immune to such failures.
Abstract: The major focus of this work was to characterize hydrodynamics in a packed-bed with and without static mixer by using Computational Fluid Dynamic (CFD). The commercial software: COMSOL MULTIPHYSICSTM Version 3.3 was used to simulate flow fields of mixed-gas reactants i.e. CO and H2. The packed-bed was a single tube with the inside diameter of 0.8 cm and the length of 1.2 cm. The static mixer was inserted inside the tube. The number of twisting elements was 1 with 0.8 cm in diameter and 1.2 cm in length. The packed-bed with and without static mixer were both packed with approximately 700 spherical structures representing catalyst pellets. Incompressible Navier-Stokes equations were used to model the gas flow inside the beds at steady state condition, in which the inlet Reynolds Number (Re) was 2.31. The results revealed that, with the insertion of static mixer, the gas was forced to flow radially inward and outward between the central portion of the tube and the tube wall. This could help improving the overall performance of the packed-bed, which could be utilized for heterogeneous catalytic reaction such as reforming and Fischer- Tropsch reactions.
Abstract: In this paper, FinFET devices are analyzed with
emphasis on sub-threshold leakage current control. This is achieved
through proper biasing of the back gate, and through the use of
asymmetric work functions for the four terminal FinFET devices. We
are also examining different configurations of multiplexers and XOR
gates using transistors of symmetric and asymmetric work functions.
Based on extensive characterization data for MUX circuits, our
proposed configuration using symmetric devices lead to leakage
current and delay improvements of 65% and 47% respectively
compared to results in the literature. For XOR gates, a 90%
improvement in the average leakage current is achieved by using
asymmetric devices. All simulations are based on a 25nm FinFET
technology using the University of Florida UFDG model.
Abstract: Work-life balance has been acknowledged and
promoted for the sake of employee retention. It is essential for a
manager to realize the human resources situation within a company to
help employees work happily and perform at their best. This paper
suggests knowledge management and critical thinking are useful to
motivate employees to think about their work-life balance. A
qualitative case study is presented, which aimed to discover the
meaning of work-life balance-s meaning from the perspective of Thai
knowledge workers and how it affects their decision-making towards
work resignation. Results found three types of work-life balance
dimensions; a work- life balance including a workplace and a private
life setting, an organizational working life balance only, and a worklife
balance only in a private life setting. These aspects all influenced
the decision-making of the employees. Factors within a theme of an
organizational work-life balance were involved with systematic
administration, fair treatment, employee recognition, challenging
assignments to gain working experience, assignment engagement,
teamwork, relationship with superiors, and working environment,
while factors concerning private life settings were about personal
demands such as an increasing their salary or starting their own
business.
Abstract: The experimental thermal performance of two heat
exchangers in closed-wet cooling tower (CWCT) was investigated in
this study. The test sections are heat exchangers which have multi path
that is used as the entrance of cooling water and are consisting of
bare-type copper tubes between 15.88mm and 19.05mm. The process
fluids are the cooling water that flows from top part of heat exchanger
to bottom side in the inner side of tube, and spray water that flows
gravitational direction in the outer side of it. Air contacts its outer side
of that as it counterflows. Heat and mass transfer coefficients and
cooling capacity were calculated with variations of process fluids,
multi path and different diameter tubes to figure out the performance
of characteristics of CWCT.
The main results were summarized as follows: The results show this
experiment is reliable with values of heat and mass transfer
coefficients comparing to values of correlations. Heat and mass
transfer coefficients and cooling capacity of two paths are higher than
these with one path using 15.88 and 19.05mm tubes. Cooling capacity
per unit volume with 15.88mm tube using one and two paths are
higher than 19.05mm tube due to increase of surface area per unit
volume.
Abstract: Cosmic showers, from their places of origin in space,
after entering earth generate secondary particles called Extensive Air
Shower (EAS). Detection and analysis of EAS and similar High
Energy Particle Showers involve a plethora of experimental setups
with certain constraints for which soft-computational tools like
Artificial Neural Network (ANN)s can be adopted. The optimality
of ANN classifiers can be enhanced further by the use of Multiple
Classifier System (MCS) and certain data - dimension reduction
techniques. This work describes the performance of certain data
dimension reduction techniques like Principal Component Analysis
(PCA), Independent Component Analysis (ICA) and Self Organizing
Map (SOM) approximators for application with an MCS formed
using Multi Layer Perceptron (MLP), Recurrent Neural Network
(RNN) and Probabilistic Neural Network (PNN). The data inputs are
obtained from an array of detectors placed in a circular arrangement
resembling a practical detector grid which have a higher dimension
and greater correlation among themselves. The PCA, ICA and SOM
blocks reduce the correlation and generate a form suitable for real
time practical applications for prediction of primary energy and
location of EAS from density values captured using detectors in a
circular grid.
Abstract: We present a novel construction of 16-QAM codewords of length n = 2k . The number of constructed codewords is 162×[4k-1×k-k+1] . When these constructed codewords are utilized as a code in OFDM systems, their peak-to-mean envelope power ratios (PMEPR) are bounded above by 3.6 . The principle of our scheme is illustrated with a four subcarrier example.
Abstract: This paper reports on the enhanced photoluminescence
(PL) of nanocomposites through the layered structuring of phosphor
and quantum dot (QD). Green phosphor of Sr2SiO4:Eu, red QDs of
CdSe/CdS/CdZnS/ZnS core-multishell, and thermo-curable resin
were used for this study. Two kinds of composite (layered and mixed)
were prepared, and the schemes for optical energy transfer between
QD and phosphor were suggested and investigated based on PL decay
characteristics. It was found that the layered structure is more effective
than the mixed one in the respects of PL intensity, PL decay and
thermal loss. When this layered nanocomposite (QDs on phosphor) is
used to make white light emitting diode (LED), the brightness is
increased by 37 %, and the color rendering index (CRI) value is raised
to 88.4 compared to the mixed case of 80.4.
Abstract: Discrimination between different classes of environmental
sounds is the goal of our work. The use of a sound recognition
system can offer concrete potentialities for surveillance and
security applications. The first paper contribution to this research
field is represented by a thorough investigation of the applicability
of state-of-the-art audio features in the domain of environmental
sound recognition. Additionally, a set of novel features obtained by
combining the basic parameters is introduced. The quality of the
features investigated is evaluated by a HMM-based classifier to which
a great interest was done. In fact, we propose to use a Multi-Style
training system based on HMMs: one recognizer is trained on a
database including different levels of background noises and is used
as a universal recognizer for every environment. In order to enhance
the system robustness by reducing the environmental variability, we
explore different adaptation algorithms including Maximum Likelihood
Linear Regression (MLLR), Maximum A Posteriori (MAP)
and the MAP/MLLR algorithm that combines MAP and MLLR.
Experimental evaluation shows that a rather good recognition rate
can be reached, even under important noise degradation conditions
when the system is fed by the convenient set of features.