Abstract: Vortices can develop in intakes of turbojet and turbo
fan aero engines during high power operation in the vicinity of solid
surfaces. These vortices can cause catastrophic damage to the engine.
The factors determining the formation of the vortex include both
geometric dimensions as well as flow parameters. It was shown that
the threshold at which the vortex forms or disappears is also
dependent on the initial flow condition (i.e. whether a vortex forms
after stabilised non vortex flow or vice-versa). A computational fluid
dynamics study was conducted to determine the difference in
thresholds between the two conditions. This is the first reported
numerical investigation of the “memory effect". The numerical
results reproduce the phenomenon reported in previous experimental
studies and additional factors, which had not been previously studied,
were investigated. They are the rate at which ambient velocity
changes and the initial value of ambient velocity. The former was
found to cause a shift in the threshold but not the later. It was also
found that the varying condition thresholds are not symmetrical about
the neutral threshold. The vortex to no vortex threshold lie slightly
further away from the neutral threshold compared to the no vortex to
vortex threshold. The results suggests that experimental investigation
of vortex formation threshold performed either in vortex to no vortex
conditions, or vice versa, solely may introduce mis-predictions
greater than 10%.
Abstract: This paper presents the use of three-dimensional finite
elements coupled with infinite elements to investigate the ground
vibrations at the surface in terms of the peak particle velocity (PPV)
due to construction of the first bore of the Dublin Port Tunnel. This
situation is analysed using a commercially available general-purpose
finite element package ABAQUS. A series of parametric studies is
carried out to examine the sensitivity of the predicted vibrations to
variations in the various input parameters required by finite element
method, including the stiffness and the damping of ground. The
results of this study show that stiffness has a more significant effect
on the PPV rather than the damping of the ground.
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: This paper proposes a novel improvement of forecasting approach based on using time-invariant fuzzy time series. In contrast to traditional forecasting methods, fuzzy time series can be also applied to problems, in which historical data are linguistic values. It is shown that proposed time-invariant method improves the performance of forecasting process. Further, the effect of using different number of fuzzy sets is tested as well. As with the most of cited papers, historical enrollment of the University of Alabama is used in this study to illustrate the forecasting process. Subsequently, the performance of the proposed method is compared with existing fuzzy time series time-invariant models based on forecasting accuracy. It reveals a certain performance superiority of the proposed method over methods described in the literature.
Abstract: A vertical SOI-based MOSFET with trench body
structure operated as 1T DRAM cell at various temperatures has been
studied and investigated. Different operation temperatures are
assigned for the device for its performance comparison, thus the
thermal stability is carefully evaluated for the future memory device
applications. Based on the simulation, the vertical SOI-based
MOSFET with trench body structure demonstrates the electrical
characteristics properly and possess conspicuous kink effect at
various operation temperatures. Transient characteristics were also
performed to prove that its programming window values and
retention time behaviors are acceptable when the new 1T DRAM cell
is operated at high operation temperature.
Abstract: This paper provides an overview of auction theory literature. We present a general review on literature of various auctions and focus ourselves specifically on an English auction. We are interested in modelling bidder's behavior in an English auction environment. And hence, we present an overview of the New Zealand wool auction followed by a model that would describe a bidder's decision making behavior from the New Zealand wool auction. The mathematical assumptions in an English auction environment are demonstrated from the perspective of the New Zealand wool auction.
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: Urbanization has been found to impact stormwater
runoff quantity and quality. A study catchment with mixed land use,
residential and industrial were investigated and the water quality
discharged from the catchment were sampled and tested for four
basic water quality parameters; BOD5, NH3-N, NO3-N and P. One
dry weather flow and several stormwater runoff were sampled.
Results were compared to the USEPA stormwater quality benchmark
values and the Interim National Water Quality Standards for
Malaysia (INWQS). The concentration of the parameters was found
to vary significantly between storms and the pollutant of concern was
found to be NO3-N.
Abstract: The picture of a perfect road construction site is the one that utilizes conventional vertical road signs and a flagman to optimize the traffic flow with minimum hazel to the public. Former research has been carried out by Department of Occupational Safety and Health (DOSH) and Ministry of Works to further enhance smoothness in traffic operations and particularly in safety issues within work zones. This paper highlights on hazardous zones in a certain road construction or road maintenance site. Most cases show that the flagman falls into high risk of fatal accidents within work zone. Various measures have been taken by both the authorities and contractors to overcome such miseries, yet it-s impossible to eliminate the usage of a flagman since it is considered the best practice. With the implementation of new technologies in automating the traffic flow in road construction site, it is possible to eliminate the usage of a flagman. The intelligent traffic light system is designed to solve problems which contribute hazardous at road construction site and to be inline with the road safety regulation which is taken into granted.
Abstract: Multi-Radio Multi-Channel (MRMC) systems are key to power control problems in wireless mesh networks (WMNs). In this paper, we present asynchronous multiple-state based power control for MRMC WMNs. First, WMN is represented as a set of disjoint Unified Channel Graphs (UCGs). Second, each network interface card (NIC) or radio assigned to a unique UCG adjusts transmission power using predicted multiple interaction state variables (IV) across UCGs. Depending on the size of queue loads and intra- and inter-channel states, each NIC optimizes transmission power locally and asynchronously. A new power selection MRMC unification protocol (PMMUP) is proposed that coordinates interactions among radios. The efficacy of the proposed method is investigated through simulations.
Abstract: The protection of groundwater resources is the great
important many semiarid and arid environments. Baghan watershed
is located in the north of Kangan in the Boshehr province in Iran. The
groundwater resources have a vital role in supplying agricultural,
drinking, domestic and industrial water demand in Baghan
watershed. For our investigation into the water quality we collected
30 samples to chemical and physical analysis. The result showed the
marl and evaporation deposits that contain anhydrite and gypsum is
the main source of groundwater pollution, and one part of the
groundwater was polluted by oil and gas industrial. Another part of
the groundwater was contaminated by urban waste water. The
electrical conductivity and captions and anions increased around of
towns and gas refinery. Although the negative impact of untreated
domestic wastewater is relatively low but the results showed strongly
the negative impact of wastewater refinery is very considerable. This
negative impact increased in downstream due to shallow aquifer.
Additionally, the agents that adversely affect the quality of
groundwater come from a variety of sources, including geology,
domestic wastewater and the Jam refinery in Baghan watershed.
Abstract: The ionization energy in semiconductor
systems in nano scale was investigated by using effective mass
approximation. By introducing the Hamiltonian of the system, the
variational technique was employed to calculate the ground state and
the ionization energy of a donor at the center and in the case that the
impurities are randomly distributed inside a cubic quantum well. The
numerical results for GaAs/GaAlAs show that the ionization energy
strongly depends on the well width for both cases and it decreases as
the well width increases. The ionization energy of a quantum wire
was also calculated and compared with the results for the well.
Abstract: To achieve competitive advantage nowadays, most of
the industrial companies are considering that success is sustained to
great product development. That is to manage the product throughout
its entire lifetime ranging from design, manufacture, operation and
destruction. Achieving this goal requires a tight collaboration
between partners from a wide variety of domains, resulting in various
product data types and formats, as well as different software tools. So
far, the lack of a meaningful unified representation for product data
semantics has slowed down efficient product development. This
paper proposes an ontology based approach to enable such semantic
interoperability. Generic and extendible product ontology is
described, gathering main concepts pertaining to the mechanical field
and the relations that hold among them. The ontology is not
exhaustive; nevertheless, it shows that such a unified representation
is possible and easily exploitable. This is illustrated thru a case study
with an example product and some semantic requests to which the
ontology responds quite easily. The study proves the efficiency of
ontologies as a support to product data exchange and information
sharing, especially in product development environments where
collaboration is not just a choice but a mandatory prerequisite.
Abstract: The optimal extraction condition of dried
Echinocactus grusonii powder was studied. The three independent
variables are raw material drying temperature, extraction
temperature, and extraction time. The dependent variables are both
yield percentage of crude extract and total phenolic quantification as
gallic acid equivalent in crude extract. The experimental design was
based on central composite design. Highest yield percentage of crude
extract could get from extraction condition at raw material drying
temperature at 60°C, extraction temperature at 15°C, and extraction
time for 25 min °C. Moreover, the crude extract with highest phenolic
occurred by extraction condition of raw material drying temperature
at 60°C, extraction temperature at 35 °C, and extraction lasting 25
min.
Abstract: In this paper, an overview of the radio over fiber (RoF) technology is provided. Obstacles for reducing the capital and operational expenses in the existing systems are discussed in various perspectives. Some possible RoF deployment scenarios for WiMAX
data transmission are proposed as a means for capital and operational
expenses reduction. IEEE 802.16a standard based end-to-end physical layer model is simulated including intensity modulated direct detection RoF technology. Finally the feasibility of RoF
technology to carry WiMAX signals between the base station and the
remote antenna units is demonstrated using the simulation results.
Abstract: The equilibrium process of plasma nitrogen species by
chemical kinetic reactions along various pressures is successfully
investigated. The equilibrium process is required in industrial
application to obtain the stable condition when heating up the
material for having homogenous reaction. Nitrogen species densities
is modeled by a continuity equation and extended Arrhenius form.
These equations are used to integrate the change of density over the
time. The integration is to acquire density and the reaction rate of
each reaction where temperature and time dependence are imposed.
A comparison is made with global model within pressure range of 1-
100mTorr and the temperature of electron is set to be higher than
other nitrogen species. The results shows that the chemical kinetic
model only agrees for high pressure because of no power imposed;
while the global model considers the external power along the
pressure range then the electron and nitrogen species give highly
quantity densities by factor of 3 to 5.
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: The purpose of this paper is to examine the inter
relationships among various leadership branding constructs of
entrepreneurs in small and medium sized enterprises (SMEs). We
employ a quantitative structural equation modeling through a new
leadership branding engagement model comprises constructs of
leader-s or entrepreneur-s personality, branding practice and
customer engagement. The results confirm that there are significant
relationships between the three constructs and the major fit indices
indicate that the data fits the proposed model. The findings provide
insights and fill in the literature gaps on statistically validated
representation of leadership branding for SMEs across new economic
regions of Malaysia that may implicate other economic zones with
similar situations. This study extends the establishment of a
leadership branding engagement model with a new mechanism of
using leaders- personality as a predictor to branding practice and
customer engagement performance.
Abstract: Under the variation of crude oil price and the impact of
greenhouse effect, it is urgent to find a potential alternative fuel.
Among these alternative fuels, non edible plant oils are the most
potential ones, because they don-t have the problem of food and
cropland competitions. Among the non-edible plant oils, Jatropha oil
is the most potential one. Jatropha oil is non-eatable oil and has good
oil quality and low temperature performance. It has potential to
become one of the most competitive biomass crude oils. The crude
plant oil will be blended with diesel fuel to be tested in a power
generator. The international collaboration between Taiwan and
Indonesia on the production of Jatropha in Indonesia will also be
presented in this study.
Abstract: Yogyakarta, as the capital city of Yogyakarta Province, has important roles in various sectors that require good provision of public transportation system. Ideally, a good transportation system should be able to accommodate the amount of travel demand. This research attempts to develop a trip generation model to predict the number of public transport passenger in Yogyakarta city. The model is built by using multiple linear regression analysis, which establishes relationship between trip number and socioeconomic attributes. The data consist of primary and secondary data. Primary data was collected by conducting household surveys which randomly selected. The resulted model is further applied to evaluate the existing TransJogja, a new Bus Rapid Transit system serves Yogyakarta and surrounding cities, shelters.