Abstract: Due to adverse pressure gradient along the diverging
walls of wide-angled diffusers, the attached flow separates from
one wall and remains attached permanently to the other wall in a
process called stalling. Stalled diffusers render the whole fluid flow
system, in which they are part of, very inefficient. There is then an
engineering need to try to understand the whole process of diffuser
stall if any meaningful attempts to improve on diffuser efficiency
are to be made. In this regard, this paper provides a data bank
contribution for the mean flow-field in wide-angled diffusers where
the complete velocity and static pressure fields, and pressure recovery
data for diffusers in the fully stalled flow regime are experimentally
measured. The measurements were carried out at Reynolds numbers
between 1.07×105 and 2.14×105 based on inlet hydraulic diameter
and centreline velocity for diffusers whose divergence angles were
between 30Ôùª and 50Ôùª. Variation of Reynolds number did not significantly
affect the velocity and static pressure profiles. The wall static
pressure recovery was found to be more sensitive to changes in the
Reynolds number. By increasing the velocity from 10 m/s to 20 m/s,
the wall static pressure recovery increased by 8.31%. However, as the
divergence angle was increased, a similar increase in the Reynolds
number resulted in a higher percentage increase in pressure recovery.
Experimental results showed that regardless of the wall to which
the flow was attached, both the velocity and pressure fields were
replicated with discrepancies below 2%.
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: Social-economic variables influence transportation
demand largely. Analyses of discrete choice model consider
social-economic variables to study traveler-s mode choice and
demand. However, to calibrate the discrete choice model needs to have
plenty of questionnaire survey. Also, an aggregative model is
proposed. The historical data of passenger volumes for high speed rail
and domestic civil aviation are employed to calibrate and validate the
model. In this study, models with different social-economic variables,
which are oil price, GDP per capita, CPI and economic growth rate,
are compared. From the results, the model with the oil price is better
than models with the other social-economic variables.
Abstract: The success of an electronic system in a System-on- Chip is highly dependent on the efficiency of its interconnection network, which is constructed from routers and channels (the routers move data across the channels between nodes). Since neither classical bus based nor point to point architectures can provide scalable solutions and satisfy the tight power and performance requirements of future applications, the Network-on-Chip (NoC) approach has recently been proposed as a promising solution. Indeed, in contrast to the traditional solutions, the NoC approach can provide large bandwidth with moderate area overhead. The selected topology of the components interconnects plays prime rule in the performance of NoC architecture as well as routing and switching techniques that can be used. In this paper, we present two generic NoC architectures that can be customized to the specific communication needs of an application in order to reduce the area with minimal degradation of the latency of the system. An experimental study is performed to compare these structures with basic NoC topologies represented by 2D mesh, Butterfly-Fat Tree (BFT) and SPIN. It is shown that Cluster mesh (CMesh) and MinRoot schemes achieves significant improvements in network latency and energy consumption with only negligible area overhead and complexity over existing architectures. In fact, in the case of basic NoC topologies, CMesh and MinRoot schemes provides substantial savings in area as well, because they requires fewer routers. The simulation results show that CMesh and MinRoot networks outperforms MESH, BFT and SPIN in main performance metrics.
Abstract: A Simultaneous Multithreading (SMT) Processor is
capable of executing instructions from multiple threads in the same
cycle. SMT in fact was introduced as a powerful architecture to
superscalar to increase the throughput of the processor.
Simultaneous Multithreading is a technique that permits multiple
instructions from multiple independent applications or threads to
compete limited resources each cycle. While the fetch unit has been
identified as one of the major bottlenecks of SMT architecture, several
fetch schemes were proposed by prior works to enhance the fetching
efficiency and overall performance.
In this paper, we propose a novel fetch policy called queue situation
identifier (QSI) which counts some kind of long latency instructions of
each thread each cycle then properly selects which threads to fetch
next cycle. Simulation results show that in best case our fetch policy
can achieve 30% on speedup and also can reduce the data cache level 1
miss rate.
Abstract: Acute toxicity of nano SiO2, ZnO, MCM-41 (Meso
pore silica), Cu, Multi Wall Carbon Nano Tube (MWCNT), Single
Wall Carbon Nano Tube (SWCNT) , Fe (Coated) to bacteria Vibrio
fischeri using a homemade luminometer , was evaluated. The values
of the nominal effective concentrations (EC), causing 20% and 50%
inhibition of biouminescence, using two mathematical models at two
times of 5 and 30 minutes were calculated. Luminometer was
designed with Photomultiplier (PMT) detector. Luminol
chemiluminescence reaction was carried out for the calibration graph.
In the linear calibration range, the correlation coefficients and
coefficient of Variation (CV) were 0.988 and 3.21% respectively
which demonstrate the accuracy and reproducibility of the instrument
that are suitable. The important part of this research depends on how
to optimize the best condition for maximum bioluminescence. The
culture of Vibrio fischeri with optimal conditions in liquid media,
were stirring at 120 rpm at a temperature of 150C to 180C and were
incubated for 24 to 72 hours while solid medium was held at 180C
and for 48 hours. Suspension of nanoparticles ZnO, after 30 min
contact time to bacteria Vibrio fischeri, showed the highest toxicity
while SiO2 nanoparticles showed the lowest toxicity. After 5 min
exposure time, the toxicity of ZnO was the strongest and MCM-41
was the weakest toxicant component.
Abstract: Use of microemulsion in enhanced oil recovery has become more attractive in recent years because of its high level of extraction efficiency. Experimental investigations have been made on characterization of microemulsions of oil-brinesurfactant/ cosurfactant system for its use in enhanced oil recovery (EOR). Sodium dodecyl sulfate, propan-1-ol and heptane were selected as surfactant, cosurfactant and oil respectively for preparation of microemulsion. The effects of salinity on the relative phase volumes and solubilization parameters have also been studied. As salinity changes from low to high value, phase transition takes place from Winsor I to Winsor II via Winsor III. Suitable microemulsion composition has been selected based on its stability and ability to reduce interfacial tension. A series of flooding experiments have been performed using the selected microemulsion. The flooding experiments were performed in a core flooding apparatus using uniform sand pack. The core holder was tightly packed with uniform sands (60-100 mesh) and saturated with brines of different salinities. It was flooded with the brine at 25 psig and the absolute permeability was calculated from the flow rate of the through sand pack. The sand pack was then flooded with the crude oil at 800 psig to irreducible water saturation. The initial water saturation was determined on the basis of mass balance. Waterflooding was conducted by placing the coreholder horizontally at a constant injection pressure at 200 pisg. After water flooding, when water-cut reached above 95%, around 0.5 pore volume (PV) of the above microemulsion slug was injected followed by chasing water. The experiments were repeated using different composition of microemulsion slug. The additional recoveries were calculated by material balance. Encouraging results with additional recovery more than 20% of original oil in place above the conventional water flooding have been observed.
Abstract: In this paper we describes the authentication for DHCP
(Dynamic Host Configuration Protocol) message which provides the
efficient key management and reduces the danger replay attack without
an additional packet for a replay attack. And the authentication for
DHCP message supports mutual authentication and provides both
entity authentication and message authentication. We applied the
authentication for DHCP message to the home network environments
and tested through a home gateway.
Abstract: Quantum cryptography offers a way of key agreement,
which is unbreakable by any external adversary. Authentication is
of crucial importance, as perfect secrecy is worthless if the identity
of the addressee cannot be ensured before sending important information.
Message authentication has been studied thoroughly, but no
approach seems to be able to explicitly counter meet-in-the-middle
impersonation attacks. The goal of this paper is the development of
an authentication scheme being resistant against active adversaries
controlling the communication channel. The scheme is built on top
of a key-establishment protocol and is unconditionally secure if built
upon quantum cryptographic key exchange. In general, the security
is the same as for the key-agreement protocol lying underneath.
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: Viral influenza A subtypes H5N1 and pandemic
H1N1 (pH1N1) have worldwide emerged and transmitted. The most
common anti-influenza drug for treatment of both seasonal and
pandemic influenza viruses is oseltamivir that nowadays becomes
resistance to influenza neuraminidase. The novel long-acting drug,
laninamivir, was discovered for treatment of the patients infected
with influenza B and influenza A viruses. In the present study,
laninamivir complexed with wild-type strain of both H5N1 and
pH1N1 viruses were comparatively determined the structures and
drug-target interactions by means of molecular dynamics (MD)
simulations. The results show that the hydrogen bonding interactions
formed between laninamivir and its binding residues are likely
similar for the two systems. Additionally, the presence of
intermolecular interactions from laninamivir to the residues in the
binding pocket is established through their side chains in accordance
with hydrogen bond interactions.
Abstract: In the end of the day, meteorological data and environmental data becomes widely used such as plant varieties selection system. Variety plant selection for planted area is of almost importance for all crops, including varieties of sugarcane. Since sugarcane have many varieties. Variety plant non selection for planting may not be adapted to the climate or soil conditions for planted area. Poor growth, bloom drop, poor fruit, and low price are to be from varieties which were not recommended for those planted area. This paper presents plant varieties selection system for planted areas in Thailand from meteorological data and environmental data by the use of decision tree techniques. With this software developed as an environmental data analysis tool, it can analyze resulting easier and faster. Our software is a front end of WEKA that provides fundamental data mining functions such as classify, clustering, and analysis functions. It also supports pre-processing, analysis, and decision tree output with exporting result. After that, our software can export and display data result to Google maps API in order to display result and plot plant icons effectively.
Abstract: An incentive for performance, as one subsystem of a
new performance management system, has been implemented in the
Thai public sector since 2004. This research investigates the
development of organizational justice in the incentive allocation by
comparing the roles of distributive and procedural justice on national
personnel-s attitudinal outcomes (incentive satisfaction and job
performance) between 2 periods, i.e. 2006 and 2008. The data were
collected via self-administered questionnaires completed by national
government officers and employees. They were stratified using multistage
sampling with 2,600 usable samples or 72.0% response rate in
2006, and 1,969 usable samples or 59.3% in 2008. The findings are:
(1) There is no difference in means between the two periods relating
to distributive justice, procedural justice, incentive satisfaction and
job performance. (2) Distributive justice and procedural justice
played more important roles in predicting incentive satisfaction and
job performance in 2008 than in 2006.
Abstract: Grid environments consist of the volatile integration
of discrete heterogeneous resources. The notion of the Grid is to
unite different users and organisations and pool their resources into
one large computing platform where they can harness, inter-operate,
collaborate and interact. If the Grid Community is to achieve this
objective, then participants (Users and Organisations) need to be
willing to donate or share their resources and permit other
participants to use their resources. Resources do not have to be
shared at all times, since it may result in users not having access to
their own resource. The idea of reward-based computing was
developed to address the sharing problem in a pragmatic manner.
Participants are offered a reward to donate their resources to the
Grid. A reward may include monetary recompense or a pro rata share
of available resources when constrained. This latter point may imply
a quality of service, which in turn may require some globally agreed
reservation mechanism. This paper presents a platform for economybased
computing using the WebCom Grid middleware. Using this
middleware, participants can configure their resources at times and
priority levels to suit their local usage policy. The WebCom system
accounts for processing done on individual participants- resources
and rewards them accordingly.
Abstract: In wireless networks, bandwidth is scare resource and it is essential to utilize it effectively. This paper analyses effects of using different bandwidth management techniques on the network performances of the Wireless Local Area Networks (WLANs) that use hybrid load balancing scheme. In particular, we study three bandwidth management schemes, namely Complete Sharing (CS), Complete Partitioning (CP), and Partial Sharing (PS). Performances of these schemes are evaluated by simulation experiments in term of percentage of network association blocking. Our results show that the CS scheme can provide relatively low blocking percentage in various network traffic scenarios whereas the PS scheme can enhance quality of services of the multimedia traffic with rather small expenses on the blocking percentage of the best effort traffic.
Abstract: Leprosy is an infectious disease caused by
Mycobacterium Leprae, this disease, generally, compromises
the neural fibers, leading to the development of disability.
Disabilities are changes that limit daily activities or social life
of a normal individual. When comes to leprosy, the study of
disability considered the functional limitation (physical
disabilities), the limitation of activity and social participation,
which are measured respectively by the scales: EHF, SALSA
and PARTICIPATION SCALE. The objective of this work is
to propose an on-line monitoring of leprosy patients, which is
based on information scales EHF, SALSA and
PARTICIPATION SCALE. It is expected that the proposed
system is applied in monitoring the patient during treatment
and after healing therapy of the disease. The correlations that
the system is between the scales create a variety of
information, presented the state of the patient and full of
changes or reductions in disability. The system provides
reports with information from each of the scales and the
relationships that exist between them. This way, health
professionals, with access to patient information, can
intervene with techniques for the Prevention of Disability.
Through the automated scale, the system shows the level of
the patient and allows the patient, or the responsible, to take a
preventive measure. With an online system, it is possible take
the assessments and monitor patients from anywhere.
Abstract: A new Feed-Forward/Feedback Generalized
Minimum Variance Pole-placement Controller to incorporate the
robustness of classical pole-placement into the flexibility of
generalized minimum variance self-tuning controller for Single-Input
Single-Output (SISO) has been proposed in this paper. The design,
which provides the user with an adaptive mechanism, which ensures
that the closed loop poles are, located at their pre-specified positions.
In addition, the controller design which has a feed-forward/feedback
structure overcomes the certain limitations existing in similar poleplacement
control designs whilst retaining the simplicity of
adaptation mechanisms used in other designs. It tracks set-point
changes with the desired speed of response, penalizes excessive
control action, and can be applied to non-minimum phase systems.
Besides, at steady state, the controller has the ability to regulate the
constant load disturbance to zero. Example simulation results using
both simulated and real plant models demonstrate the effectiveness of
the proposed controller.
Abstract: This study aims to determine the level of resistance of Hevea brasiliensis and Paraserianthes falcataria (synonym: Falcataria molucana) against wood rot fungi Pleurotus ostreatus based on Indonesian standard SNI 01.7207-2006 and Japanese standard JIS K 1571-2004. The variables measured were visual appearance and weight loss percentage of wood based on longitudinal and cross section fiber directions of rubber wood and sengon wood. Measurement of oven dry weight loss of wood samples performed after 12 weeks incubation. Replication performed was 10 times at each treatment combination. The results based on SNI 01.7207-2006, weight loss value of H. brasiliensis and P. falcataria wood with fiber direction longitudinal were 23,12 and 22,25% respectively and cross section were 20,77 and 18,76% respectively, and all were classified to resistance class IV (no resistance). The results based on JIS K 1571-2004, weight loss value of both woods with fiber direction cross section were 10,95 and 14,20% respectively.
Abstract: the effects of refining and alkaline chemicals on potential of recycling bleached chemical pulp of bagasse were investigated in this study. Recycling was done until three times. Handsheet properties such as, apparent density, light scattering coefficient, tear index, burst index, breaking length, and fold number according to TAPPI standard were measured. Water retention value also was used to considering the treatments during recycling. Refining enhanced the strength of recycled pulp by increasing fiber flexibility and swelling ability, whereas by applying chemical treatment didn't observe any improvement. The morphology of recycled fiber was considered with scanning electron microscopy (SEM).
Abstract: The problem of lot sizing, sequencing and scheduling
multiple products in flow line production systems has been studied
by several authors. Almost all of the researches in this area assumed
that setup times and costs are sequence –independent even though
sequence dependent setups are common in practice. In this paper we
present a new mixed integer non linear program (MINLP) and a
heuristic method to solve the problem in sequence dependent case.
Furthermore, a genetic algorithm has been developed which applies
this constructive heuristic to generate initial population. These two
proposed solution methods are compared on randomly generated
problems. Computational results show a clear superiority of our
proposed GA for majority of the test problems.