Abstract: This paper deals with a novel technique for the
fabrication of Spiral grooves in a dynamic thrust bearing. The main
scheme proposed in this paper is to fabricate the microgrooves using
desktop forming system. This process has advantages compared to the
conventional electro-chemical machining in the viewpoint of a higher
productivity. For this reason, a new testing apparatus is designed and
built for press forming microgrooves on a surface of the thrust bearing.
The material used in this study is sintered Cu-Fe alloy. The effects of
the forming load on the performance of micro press forming are
experimentally investigated. From the experimental results, formed
depths are closed to the target ones with increasing the forming load.
Abstract: In this paper, Selective Adaptive Parallel Interference Cancellation (SA-PIC) technique is presented for Multicarrier Direct Sequence Code Division Multiple Access (MC DS-CDMA) scheme. The motivation of using SA-PIC is that it gives high performance and at the same time, reduces the computational complexity required to perform interference cancellation. An upper bound expression of the bit error rate (BER) for the SA-PIC under Rayleigh fading channel condition is derived. Moreover, the implementation complexities for SA-PIC and Adaptive Parallel Interference Cancellation (APIC) are discussed and compared. The performance of SA-PIC is investigated analytically and validated via computer simulations.
Abstract: As wireless sensor networks are energy constraint networks
so energy efficiency of sensor nodes is the main design issue.
Clustering of nodes is an energy efficient approach. It prolongs the
lifetime of wireless sensor networks by avoiding long distance communication.
Clustering algorithms operate in rounds. Performance of
clustering algorithm depends upon the round time. A large round
time consumes more energy of cluster heads while a small round
time causes frequent re-clustering. So existing clustering algorithms
apply a trade off to round time and calculate it from the initial
parameters of networks. But it is not appropriate to use initial
parameters based round time value throughout the network lifetime
because wireless sensor networks are dynamic in nature (nodes can be
added to the network or some nodes go out of energy). In this paper
a variable round time approach is proposed that calculates round
time depending upon the number of active nodes remaining in the
field. The proposed approach makes the clustering algorithm adaptive
to network dynamics. For simulation the approach is implemented
with LEACH in NS-2 and the results show that there is 6% increase
in network lifetime, 7% increase in 50% node death time and 5%
improvement over the data units gathered at the base station.
Abstract: Solar water heating (SWH) systems are gaining popularity in ASEAN in the midst of increasing number of affluent population in society and environmental concerns from seemingly unchanged reliance on fossil-based fuels. The penetration of these systems and technologies into ASEAN markets is a welcome development; however there is a need for the method of assessment of their thermal performances. This paper discusses the reasons for this need and a suitable method for thermal performance evaluation of SWH systems in ASEAN. The paper also calls on research to be focused on the establishment of reliable data to be entered into the performance rating software. The establishment of accredited solar systems testing facilities can help boost the competitiveness of ASEAN solar industry.
Abstract: In this paper, a clustering algorithm named KHarmonic
means (KHM) was employed in the training of Radial
Basis Function Networks (RBFNs). KHM organized the data in
clusters and determined the centres of the basis function. The popular
clustering algorithms, namely K-means (KM) and Fuzzy c-means
(FCM), are highly dependent on the initial identification of elements
that represent the cluster well. In KHM, the problem can be avoided.
This leads to improvement in the classification performance when
compared to other clustering algorithms. A comparison of the
classification accuracy was performed between KM, FCM and KHM.
The classification performance is based on the benchmark data sets:
Iris Plant, Diabetes and Breast Cancer. RBFN training with the KHM
algorithm shows better accuracy in classification problem.
Abstract: This paper presents a semi-supervised learning algorithm called Iterative-Cross Training (ICT) to solve the Web pages classification problems. We apply Inductive logic programming (ILP) as a strong learner in ICT. The objective of this research is to evaluate the potential of the strong learner in order to boost the performance of the weak learner of ICT. We compare the result with the supervised Naive Bayes, which is the well-known algorithm for the text classification problem. The performance of our learning algorithm is also compare with other semi-supervised learning algorithms which are Co-Training and EM. The experimental results show that ICT algorithm outperforms those algorithms and the performance of the weak learner can be enhanced by ILP system.
Abstract: Power-line networks are widely used today for broadband data transmission. However, due to multipaths within the broadband power line communication (BPLC) systems owing to stochastic changes in the network load impedances, branches, etc., network or channel capacity performances are affected. This paper attempts to investigate the performance of typical medium voltage channels that uses Orthogonal Frequency Division Multiplexing (OFDM) techniques with Quadrature Amplitude Modulation (QAM) sub carriers. It has been observed that when the load impedances are different from line characteristic impedance channel performance decreases. Also as the number of branches in the link between the transmitter and receiver increases a loss of 4dB/branch is found in the signal to noise ratio (SNR). The information presented in the paper could be useful for an appropriate design of the BPLC systems.
Abstract: In this paper, a mathematical model is proposed to
estimate the dropping probabilities of cellular wireless networks by
queuing handoff instead of reserving guard channels. Usually, prioritized
handling of handoff calls is done with the help of guard channel
reservation. To evaluate the proposed model, gamma inter-arrival and
general service time distributions have been considered. Prevention of
some of the attempted calls from reaching to the switching center due
to electromagnetic propagation failure or whimsical user behaviour
(missed call, prepaid balance etc.), make the inter-arrival time of
the input traffic to follow gamma distribution. The performance is
evaluated and compared with that of guard channel scheme.
Abstract: Voltage flicker is a disturbance in electrical power
systems. The reason for this disturbance is mainly the large nonlinear
loads such as electric arc furnaces. Synchronous static
compensator (STATCOM) is considered as a proper technique to
mitigate the voltage flicker. Application of more suitable and precise
power electronic converter leads to a more precise performance of the
compensator. In this paper a three-level 12-pulse voltage source
inverter (VSI) with a 12-terminal transformer connected to the ac
system is studied and the obtained results are compared with the
performance of a STATCOM using a simple two-level VSI and an
optimal and more precise performance of the proposed scheme is
achieved.
Abstract: This paper proposes an efficient lattice-reduction-aided
detection (LRD) scheme to improve the detection performance of
MIMO-OFDM system. In this proposed scheme, V candidate symbols
are considered at the first layer, and V probable streams are
detected with LRD scheme according to the first detected V candidate
symbols. Then, the most probable stream is selected through a ML
test. Since the proposed scheme can more accurately detect initial
symbol and can reduce transmission of error to rest symbols, the
proposed scheme shows more improved performance than conventional
LRD with very low complexity.
Abstract: High voltage generators are being subject to higher
voltage rating and are being designed to operate in harsh conditions.
Stator windings are the main component of generators in which
Electrical, magnetically and thermal stresses remain major failures
for insulation degradation accelerated aging. A large number of
generators failed due to stator winding problems, mainly insulation
deterioration. Insulation degradation assessment plays vital role in the
asset life management. Mostly the stator failure is catastrophic
causing significant damage to the plant. Other than generation loss,
stator failure involves heavy repair or replacement cost. Electro
thermal analysis is the main characteristic for improvement design of
stator slot-s insulation. Dielectric parameters such as insulation
thickness, spacing, material types, geometry of winding and slot are
major design consideration. A very powerful method available to
analyze electro thermal performance is Finite Element Method
(FEM) which is used in this paper. The analysis of various stator coil
and slot configurations are used to design the better dielectric system
to reduce electrical and thermal stresses in order to increase the
power of generator in the same volume of core. This paper describes
the process used to perform classical design and improvement
analysis of stator slot-s insulation.
Abstract: The volume of biosolids produced in Malaysia
nowadays had increased proportionally to its population size. The end
products from the waste treatments were mounting, thus inevitable
that in the end the environment will be surrounded by the waste. This
study was conducted to investigate the suitability of biosolids to be
reused as fertilizer for non-food crop. By varying the concentration of
biosolids applied onto the soil, growth of five ornamental plant
samples were tested for eight consecutive weeks. The results show
that the pH of the soil after the addition of biosolids ranges from 6.45
to 6.56 which is suitable for the plant growth. The soil samples that
contains biosolid also show higher amount of macronutrients (N, P,
K) and the heavy metals content are significantly increased in the
plant however it does not exceed the guidelines drawn by the
Environmental Protection Agency. It is also proven that there was
only small significant different in the performance of plant growth
between biosolids and commercial fertilizer. It can be seen that
biosolids was able to perform just as well as commercial fertilizer.
Abstract: A study was carried out at the Rice Research Institute of Iran (RRII) to investigate the effect of rollers differential peripheral speed of commercial rubber roll husker and paddy moisture content on the husking index and percentage of broken rice. The experiment was conducted at six levels of rollers differential speed (1.5, 2.2, 2.9, 3.6, 4.3 and 5 m/s) and three levels of paddy moisture content (8-9, 10-11 and 12-13% w.b.). Two common paddy varieties namely, Binam and Khazer, were selected for this study. Results revealed that the effect of rollers differential speed and moisture content significantly (P
Abstract: The increasingly sophisticated technologies have now been able to provide assistance for surgeons to improve surgical
performance through various training programs. Equally important to learning skills is the assessment method as it determines the learning and technical proficiency of a trainee. A consistent and
rigorous assessment system will ensure that trainees acquire the specific level of competency prior to certification. This paper
reviews the methods currently in use for assessment of surgical
skill and some modern techniques using computer-based
measurements and virtual reality systems for more quantitative
measurements
Abstract: Multicarrier code-division multiple-access is one of the
effective techniques to gain its multiple access capability, robustness
against fading, and to mitigate the ISI. In this paper, we propose an
improved mulcarrier CDMA system with adaptive subchannel
allocation. We analyzed the performance of our proposed system in
frequency selective fading environment with narrowband interference
existing and compared it with that of parallel transmission over many
subchannels (namely, conventional MC-CDMA scheme) and
DS-CDMA system. Simulation results show that adaptive subchannel
allocation scheme, when used in conventional multicarrier CDMA
system, the performance will be greatly improved.
Abstract: In this paper, a wavelet-based neural network (WNN) classifier for recognizing EEG signals is implemented and tested under three sets EEG signals (healthy subjects, patients with epilepsy and patients with epileptic syndrome during the seizure). First, the Discrete Wavelet Transform (DWT) with the Multi-Resolution Analysis (MRA) is applied to decompose EEG signal at resolution levels of the components of the EEG signal (δ, θ, α, β and γ) and the Parseval-s theorem are employed to extract the percentage distribution of energy features of the EEG signal at different resolution levels. Second, the neural network (NN) classifies these extracted features to identify the EEGs type according to the percentage distribution of energy features. The performance of the proposed algorithm has been evaluated using in total 300 EEG signals. The results showed that the proposed classifier has the ability of recognizing and classifying EEG signals efficiently.
Abstract: Sediment formation and its transport along the river course is considered as important hydraulic consideration in river engineering. Their impact on the morphology of rivers on one hand and important considerations of which in the design and construction of the hydraulic structures on the other has attracted the attention of experts in arid and semi-arid regions. Under certain conditions where the momentum energy of the flow stream reaches a specific rate, the sediment materials start to be transported with the flow. This can usually be analyzed in two different categories of suspended and bed load materials. Sedimentation phenomenon along the waterways and the conveyance of vast volume of materials into the canal networks can potentially influence water abstraction in the intake structures. This can pose a serious threat to operational sustainability and water delivery performance in the canal networks. The situation is serious where ineffective watershed management (poor vegetation cover in the water basin) is the underlying cause of soil erosion which feeds the materials into the waterways that intern would necessitate comprehensive study. The present paper aims to present an analytical investigation of the sediment process in the waterways on one hand and estimation of the sediment load transport into the lined canals using the SHARC software on the other. For this reason, the paper focuses on the comparative analysis of the hydraulic behaviors of the Sabilli main canal that feeds the pumping station with that of the Western canal in the Greater Dezful region to identify effective factors in sedimentation and ways of mitigating their impact on water abstraction in the canal systems. The method involved use of observational data available in the Dezful Dastmashoon hydrometric station along a 6 km waterway of the Sabilli main canal using the SHARC software to estimate the suspended load concentration and bed load materials. Results showed the transport of a significant volume of sediment loads from the waterways into the canal system which is assumed to have arisen from the absence of stilling basin on one hand and the gravity flow on the other has caused serious challenges. This is contrary to what occurs in the Sabilli canal, where the design feature which incorporates a settling basin just before the pumping station is the major cause of reduced sediment load transport into the canal system.Results showed that modification of the present design features by constructing a settling basin just upstream of the western intake structure can considerably reduce the entry of sediment materials into the canal system. Not only this can result in the sustainability of the hydraulic structures but can also improve operational performance of water conveyance and distribution system, all of which are the pre-requisite to secure reliable and equitable water delivery regime for the command area.
Abstract: The use of High Order Statistics (HOS) analysis is
expected to provide so many candidates of features that can be selected for pattern recognition. More candidates of the feature can
be extracted using simple manipulation through a specific mathematical function prior to the HOS analysis. Feature extraction
method using HOS analysis combined with Difference to the Nth-Power manipulation has been examined in application for Automatic
Modulation Recognition (AMR) to perform scheme recognition of three digital modulation signal, i.e. QPSK-16QAM-64QAM in the
AWGN transmission channel. The simulation results is reported
when the analysis of HOS up to order-12 and the manipulation of Difference to the Nth-Power up to N = 4. The obtained accuracy rate
of AMR using the method of Simple Decision obtained 90% in SNR > 10 dB in its classifier, while using the method of Voted Decision is
96% in SNR > 2 dB.
Abstract: One of the primary uses of higher order statistics in
signal processing has been for detecting and estimation of non-
Gaussian signals in Gaussian noise of unknown covariance. This is
motivated by the ability of higher order statistics to suppress additive
Gaussian noise. In this paper, several methods to test for non-
Gaussianity of a given process are presented. These methods include
histogram plot, kurtosis test, and hypothesis testing using cumulants
and bispectrum of the available sequence. The hypothesis testing is
performed by constructing a statistic to test whether the bispectrum
of the given signal is non-zero. A zero bispectrum is not a proof of
Gaussianity. Hence, other tests such as the kurtosis test should be
employed. Examples are given to demonstrate the performance of the
presented methods.
Abstract: This paper addresses the problems encountered by conventional distance relays when protecting double-circuit transmission lines. The problems arise principally as a result of the mutual coupling between the two circuits under different fault conditions; this mutual coupling is highly nonlinear in nature. An adaptive protection scheme is proposed for such lines based on application of artificial neural network (ANN). ANN has the ability to classify the nonlinear relationship between measured signals by identifying different patterns of the associated signals. One of the key points of the present work is that only current signals measured at local end have been used to detect and classify the faults in the double circuit transmission line with double end infeed. The adaptive protection scheme is tested under a specific fault type, but varying fault location, fault resistance, fault inception angle and with remote end infeed. An improved performance is experienced once the neural network is trained adequately, which performs precisely when faced with different system parameters and conditions. The entire test results clearly show that the fault is detected and classified within a quarter cycle; thus the proposed adaptive protection technique is well suited for double circuit transmission line fault detection & classification. Results of performance studies show that the proposed neural network-based module can improve the performance of conventional fault selection algorithms.