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: In this work, axisymetric CFD simulation of fixed bed
GTL reactor has been conducted, using computational fluid dynamics
(CFD). In fixed bed CFD modeling, when N (tube-to-particle
diameter ratio) has a large value, it is common to consider the packed
bed as a porous media. Synthesis gas (a mixture of predominantly
carbon monoxide and hydrogen) was fed to the reactor. The reactor
length was 20 cm, divided to three sections. The porous zone was in
the middle section of the reactor. The model equations were solved
employing finite volume method. The effects of particle diameter,
bed voidage, fluid velocity and bed length on pressure drop have
been investigated. Simulation results showed these parameters could
have remarkable impacts on the reactor pressure drop.
Abstract: This paper contributes to the debate on the proximate
causes of climate change. Also, it discusses the impact of the global
temperature increases since the beginning of the twentieth century
and the effectiveness of climate change models in isolating the
primary cause (anthropogenic influences or natural variability in
temperature) of the observed temperature increases that occurred
within this period. The paper argues that if climate scientist and
policymakers ignore the anthropogenic influence (greenhouse gases)
on global warming on the pretense of lack of agreement among
various climate models and their inability to account for all the
necessary factors of global warming at all levels the current efforts of
greenhouse emissions control and global warming as a whole could
be exacerbated.
Abstract: This paper presents the new results of energy plant –
rye and triticale at yellow ripeness and ripe, pre-treatment in high
pressure steam reactor and monosaccharide extraction. There were
investigated the influence of steam pressure (20 to 22 bar), retention
duration (180 to 240 s) and catalytic sulphuric acid concentration
strength (0 to 0.5 %) on the pre-treatment process, contents of
monosaccharides (glucose, arabinose, xylose, mannose) and
undesirable by-compounds (furfural and HMF) in the reactor. The
study has determined that the largest amount of monosaccharides
(37.2 % of glucose, 2.7 % of arabinose, 8.4 % of xylose, and 1.3 %
of mannose) was received in the rye at ripe, the samples of which
were mixed with 0.5 % concentration of catalytic sulphuric acid, and
hydrolysed in the reactor, where the pressure was 20 bar, whereas the
reaction time – 240 s.
Abstract: This paper illustrates why existing technology
acceptance models are only of limited use for predicting and
explaining the adoption of future information and communication
technologies. It starts with a general overview over technology
adoption processes, and presents several theories for the acceptance
as well as adoption of traditional information technologies. This is
followed by an overview over the recent developments in the area of
information and communication technologies. Based on the
arguments elaborated in these sections, it is shown why the factors
used to predict adoption in existing systems, will not be sufficient for
explaining the adoption of future information and communication
technologies.
Abstract: In recent years, “Bottom-up Planning Approach" has been widely accepted and expanded from planning theorists. Citizen participation becomes more important in decision-making in informal settlements. Many of previous projects and strategies due to ignorance of citizen participation, have been failed facing with informal settlements and in some cases lead physical expansion of these neighbourhoods. According to recent experiences, the new participatory approach was in somehow successful. This paper focuses on local experiences in Iran. A considerable amount of people live in informal settlements in Iran. With the previous methods, the government could not solve the problems of these settlements. It is time to examine new methods such as empowerment of the local citizens and involve them to solve the current physical, social, and economic problems. The paper aims to address the previous and new strategies facing with informal settlements, the conditions under which citizens could be involved in planning process, limits and potentials of this process, the main actors and issues and finally motivations that are able to promote citizen participation. Documentary studies, observation, interview and questionnaire have been used to achieve the above mentioned objectives. Nearly 80 percent of responder in Saadi Community are ready to participate in regularising their neighbourhoods, if pre-conditions of citizen involvement are being provided. These pre-conditions include kind of problem and its severity, the importance of issue, existence of a short-term solution, etc. Moreover, confirmation of dweller-s ownership can promote the citizen engagement in participatory projects.
Abstract: Threedimensional numerical simulations are conducted on a full scale CANDU Moderator and Transient variations of the temperature and velocity distributions inside the tank are determined. The results show that the flow and temperature distributions inside the moderator tank are three dimensional and no symmetry plane can be identified.Competition between the upward moving buoyancy driven flows and the downward moving momentum driven flows, results in the formation of circulation zones. The moderator tank operates in the buoyancy driven mode and any small disturbances in the flow or temperature makes the system unstable and asymmetric. Different types of temperature fluctuations are noted inside the tank: (i) large amplitude are at the boundaries between the hot and cold (ii) low amplitude are in the core of the tank (iii) high frequency fluctuations are in the regions with high velocities and (iv) low frequency fluctuations are in the regions with lower velocities.
Abstract: Identifying protein coding regions in DNA sequences is a basic step in the location of genes. Several approaches based on signal processing tools have been applied to solve this problem, trying to achieve more accurate predictions. This paper presents a new predictor that improves the efficacy of three techniques that use the Fourier Transform to predict coding regions, and that could be computed using an algorithm that reduces the computation load. Some ideas about the combination of the predictor with other methods are discussed. ROC curves are used to demonstrate the efficacy of the proposed predictor, based on the computation of 25 DNA sequences from three different organisms.
Abstract: Active network was developed to solve the problem of
the current sharing-based network–difficulty in applying new
technology, service or standard, and duplicated operation at several
protocol layers. Active network can transport the packet loaded with
the executable codes, which enables to change the state of the network
node. However, if the network node is placed in the sharing-based
network, security and safety issues should be resolved. To satisfy this
requirement, various security aspects are required such as
authentication, authorization, confidentiality and integrity. Among
these security components, the core factor is the encryption key. As a
result, this study is designed to propose the scheme that manages the
encryption key, which is used to provide security of the
comprehensive active directory, based on the domain.
Abstract: It-s known that incorporating prior knowledge into support
vector regression (SVR) can help to improve the approximation
performance. Most of researches are concerned with the incorporation
of knowledge in form of numerical relationships. Little work,
however, has been done to incorporate the prior knowledge on the
structural relationships among the variables (referred as to Structural
Prior Knowledge, SPK). This paper explores the incorporation of SPK
in SVR by constructing appropriate admissible support vector kernel
(SV kernel) based on the properties of reproducing kernel (R.K).
Three-levels specifications of SPK are studies with the corresponding
sub-levels of prior knowledge that can be considered for the method.
These include Hierarchical SPK (HSPK), Interactional SPK (ISPK)
consisting of independence, global and local interaction, Functional
SPK (FSPK) composed of exterior-FSPK and interior-FSPK. A
convenient tool for describing the SPK, namely Description Matrix
of SPK is introduced. Subsequently, a new SVR, namely Motivated
Support Vector Regression (MSVR) whose structure is motivated
in part by SPK, is proposed. Synthetic examples show that it is
possible to incorporate a wide variety of SPK and helpful to improve
the approximation performance in complex cases. The benefits of
MSVR are finally shown on a real-life military application, Air-toground
battle simulation, which shows great potential for MSVR to
the complex military applications.
Abstract: A lightpipe is an about 99 percent specular reflective
mirror pipe or duct that is used for the transmission of the daylight
from the outside into a building. The lightpipes are usually used in
the daylighting buildings, in the residential, industrial and
commercial sectors. This paper is about the performances of a
lightpipe installed in a laboratory (3 m x 2.6 m x 3 m) without
windows. The aim is to analyse the luminous intensity distribution
for several sky/sun conditions. The lightpipe was monitored during
the year 2006. The lightpipe is 1 m long and the diameter of the top
collector and of the internal diffuser device is 0.25 m. In the
laboratory there are seven illuminance sensors: one external is
located on the roof of the laboratory and six internal sensors are
connected to a data acquisition system. The internal sensors are
positioned under the internal diffusive device at an height of 0.85 m
from the floor to simulate a working plane. The numerical data are
obtained through a simulation software. This paper shows the
comparison between the experimental and numerical results
concerning the behavior of the lightpipe.
Abstract: Nowadays, efficiency, effectiveness and economy are regarded as the main objectives of managers and the secret of the continuity of an organization in competing economy. In such competing settings, it is essential that the management of an organization has not been neglected and been obliged to identify quickly the opportunities for improving the operation of organization and remove the shortcomings of their managed system in order to use the opportunities for development. Operational auditing is a useful tool for system adjustment and leading an organization toward its objectives. Operational auditing is indeed a viewpoint which identifies the causes of insufficiencies, weaknesses and deficiencies of system and plans to eliminate them. Operational auditing is useful in the effectiveness and optimization of executive managers- decisions and increasing the efficiency and economy of their performance in the future and prevents the waste and incorrect use of resources. Evidence shows that operational auditing is used at a limited level in Iran. This matter raises some questions like the following ones in the minds. Why do a limited number of corporations use operational auditing? Which factors can guarantee its full implementation? What obstacles are there in its implementation? The purpose of this article is to determine executive objectives, the operation domain of operational auditing, the components of operational auditing and the executive obstacles to operational auditing in Iran.
Abstract: An Advance Driver Assistance System (ADAS) is a computer system on board a vehicle which is used to reduce the risk of vehicular accidents by monitoring factors relating to the driver, vehicle and environment and taking some action when a risk is identified. Much work has been done on assessing vehicle and environmental state but there is still comparatively little published work that tackles the problem of driver state. Visual attention is one such driver state. In fact, some researchers claim that lack of attention is the main cause of accidents as factors such as fatigue, alcohol or drug use, distraction and speeding all impair the driver-s capacity to pay attention to the vehicle and road conditions [1]. This seems to imply that the main cause of accidents is inappropriate driver behaviour in cases where the driver is not giving full attention while driving. The work presented in this paper proposes an ADAS system which uses an image based template matching algorithm to detect if a driver is failing to observe particular windscreen cells. This is achieved by dividing the windscreen into 24 uniform cells (4 rows of 6 columns) and matching video images of the driver-s left eye with eye-gesture templates drawn from images of the driver looking at the centre of each windscreen cell. The main contribution of this paper is to assess the accuracy of this approach using Receiver Operating Characteristic analysis. The results of our evaluation give a sensitivity value of 84.3% and a specificity value of 85.0% for the eye-gesture template approach indicating that it may be useful for driver point of regard determinations.
Abstract: The plant world is the source of many medicines.
Recently, researchers have estimated that there are approximately
400,000 plant species worldwide, of which about a quarter or a third
have been used by societies for medicinal purposes. The human uses
of plants for thousands of years to treat various ailments, in many
developing countries, much of the population trust in traditional
doctors and their collections of medicinal plants to treat them.
Essential oils have many therapeutic properties. In herbal medicine,
they are used for their antiseptic properties against infectious
diseases of fungal origin, against dermatophytes, those of bacterial
origin. The aim of our study is to determine the antimicrobial effect
of essential oils of the plant Trigonella focnum greacum on some
pathogenic bacteria, it is a medicinal plant used in traditional
therapy. The test adopted is based on the diffusion method on solid
medium (Antibiogram), this method determines the sensitivity or
resistance of a microorganism vis-à-vis the extract studied. Our study
reveals that the essential oil of the plant Trigonella focnum greacum
has a different effect on the resistance of germs. For staphiloccocus
Pseudomonnas aeroginosa and Krebsilla, are moderately sensitive
strains, also Escherichia coli and Candida albicans represents a high
sensitivity. By against Proteus is a strain that represents a weak
sensitivity.
Abstract: The gel-supported precipitation (GSP) process can be
used to make spherical particles (spherules) of nuclear fuel,
particularly for very high temperature reactors (VHTR) and even for
implementing the process called SPHEREPAC. In these different
cases, the main characteristics are the sphericity of the particles to be
manufactured and the control over their grain size. Nonetheless,
depending on the specifications defined for these spherical particles,
the GSP process has intrinsic limits, particularly when fabricating
very small particles. This paper describes the use of secondary
fragmentation (water, water/PVA and uranyl nitrate) on solid
surfaces under varying temperature and vibration conditions to assess
the relevance of using this new technique to manufacture very small
spherical particles by means of a modified GSP process. The
fragmentation mechanisms are monitored and analysed, before the
trends for its subsequent optimised application are described.
Abstract: Protection of slope and embankment from erosion has
become an important issue in Bangladesh. The constructions of
strong structures require large capital, integrated designing, high
maintenance cost. Strong structure methods have negative impact on
the environment and sometimes not function for the design period.
Plantation of vetiver system along the slopes is an alternative
solution. Vetiver not only serves the purpose of slope protection but
also adds green environment reducing pollution. Vetiver is available
in almost all the districts of Bangladesh. This paper presents the
application of vetiver system with geo-jute, for slope protection and
erosion control of embankments and slopes. In-situ shear tests have
been conducted on vetiver rooted soil system to find the shear
strength. The shear strength and effective soil cohesion of vetiver
rooted soil matrix are respectively 2.0 times and 2.1 times higher than
that of the bared soil. Similar trends have been found in direct shear
tests conducted on laboratory reconstituted samples. Field trials have
been conducted in road embankment and slope protection with
vetiver at different sites. During the time of vetiver root growth the
soil protection has been accomplished by geo-jute. As the geo-jute
degrades with time, vetiver roots grow and take over the function of
geo-jutes. Slope stability analyses showed that vegetation increase
the factor of safety significantly.
Abstract: A DC-to-DC converter for applications involving a
source with widely varying voltage conditions with loads requiring
constant voltage from full load down to no load is presented.
The switching regulator considered is a Buck converter with Pulse
Skipping Modulation control whereby pulses applied to the switch
are blocked or released on output voltage crossing a predetermined
value. Results of the study on the performance of regulator circuit
are presented. The regulator regulates over a wide input voltage range
with slightly higher ripple content and good transient response. Input
current spectrum indicates a good EMI performance with crowding
of components at low frequency range.
Abstract: The number of the companies accepting RFID in Korea
has been increased continuously due to the domestic development of
information technology. The acceptance of RFID by companies in
Korea enabled them to do business with many global enterprises in a
much more efficient and effective way. According to a survey[33,
p76], many companies in Korea have used RFID for inventory or
distribution manages. But, the use of RFID in the companies in Korea
is in the early stages and its potential value hasn-t fully been realized
yet. At this time, it would be very important to investigate the factors
that affect RFID acceptance. For this study, many previous studies
were referenced and some RFID experts were interviewed. Through
the pilot test, four factors were selected - Security Trust, Employee
Knowledge, Partner Influence, Service Provider Trust - affecting
RFID acceptance and an extended technology acceptance
model(e-TAM) was presented with those factors. The proposed model
was empirically tested using data collected from employees in
companies or public enterprises. In order to analyze some
relationships between exogenous variables and four variables in TAM,
structural equation modeling(SEM) was developed and SPSS12.0 and
AMOS 7.0 were used for analyses. The results are summarized as
follows: 1) security trust perceived by employees positively
influences on perceived usefulness and perceived ease of use; 2)
employee-s knowledge on RFID positively influences on only
perceived ease of use; 3) a partner-s influence for RFID acceptance
positively influences on only perceived usefulness; 4) service provider
trust very positively influences on perceived usefulness and perceived
ease of use 5) the relationships between TAM variables are the same as
the previous studies.
Abstract: This paper presents a cold chain monitoring system which focuses on assessment of quality and dynamic pricing information about food in cold chain. Cold chain is composed of many actors and stages; however it can be seen as a single entity since a breakdown in temperature control at any stage can impact the final quality of the product. In a cold chain, the shelf life, quality, and safety of perishable food throughout the supply chain is greatly impacted by environmental factors especially temperature. In this paper, a prototype application is implemented to retrieve timetemperature history, the current quality and the dynamic price setting according to changing quality impacted by temperature fluctuations in real-time.
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.