Abstract: This paper describes the development of a fully
automated measurement software for antenna radiation pattern
measurements in a Compact Antenna Test Range (CATR). The
CATR has a frequency range from 2-40 GHz and the measurement
hardware includes a Network Analyzer for transmitting and
Receiving the microwave signal and a Positioner controller to control
the motion of the Styrofoam column. The measurement process
includes Calibration of CATR with a Standard Gain Horn (SGH)
antenna followed by Gain versus angle measurement of the Antenna
under test (AUT). The software is designed to control a variety of
microwave transmitter / receiver and two axis Positioner controllers
through the standard General Purpose interface bus (GPIB) interface.
Addition of new Network Analyzers is supported through a slight
modification of hardware control module. Time-domain gating is
implemented to remove the unwanted signals and get the isolated
response of AUT. The gated response of the AUT is compared with
the calibration data in the frequency domain to obtain the desired
results. The data acquisition and processing is implemented in
Agilent VEE and Matlab. A variety of experimental measurements
with SGH antennas were performed to validate the accuracy of
software. A comparison of results with existing commercial
softwares is presented and the measured results are found to be
within .2 dBm.
Abstract: The drastic increase in the usage of SMS technology
has led service providers to seek for a solution that enable users of
mobile devices to access services through SMSs. This has resulted in
the proposal of solutions towards SMS-based service invocation in
service oriented environments. However, the dynamic nature of
service-oriented environments coupled with sudden load peaks
generated by service request, poses performance challenges to
infrastructures for supporting SMS-based service invocation. To
address this problem we adopt load balancing techniques. A load
balancing model with adaptive load balancing and load monitoring
mechanisms as its key constructs is proposed. The load balancing
model then led to realization of Least Loaded Load Balancing
Framework (LLLBF). Evaluation of LLLBF benchmarked with round
robin (RR) scheme on the queuing approach showed LLLBF
outperformed RR in terms of response time and throughput.
However, LLLBF achieved better result in the cost of high
processing power.
Abstract: This paper is focusing on designing a control system
for wind turbine which can control the speed and output power
according to arbitrary algorithm. Reference Tracking Method is used
to control the turbine spinning speed in order to increase its output
energy.
Abstract: In this work we present a solution for DAGC (Digital
Automatic Gain Control) in WLAN receivers compatible to IEEE 802.11a/g standard. Those standards define communication in 5/2.4
GHz band using Orthogonal Frequency Division Multiplexing OFDM modulation scheme. WLAN Transceiver that we have used
enables gain control over Low Noise Amplifier (LNA) and a
Variable Gain Amplifier (VGA). The control over those signals is
performed in our digital baseband processor using dedicated hardware block DAGC. DAGC in this process is used to automatically control the VGA and LNA in order to achieve better
signal-to-noise ratio, decrease FER (Frame Error Rate) and hold the
average power of the baseband signal close to the desired set point.
DAGC function in baseband processor is done in few steps: measuring power levels of baseband samples of an RF signal,accumulating the differences between the measured power level and
actual gain setting, adjusting a gain factor of the accumulation, and
applying the adjusted gain factor the baseband values. Based on the measurement results of RSSI signal dependence to input power we have concluded that this digital AGC can be implemented applying
the simple linearization of the RSSI. This solution is very simple but also effective and reduces complexity and power consumption of the
DAGC. This DAGC is implemented and tested both in FPGA and in ASIC as a part of our WLAN baseband processor. Finally, we have integrated this circuit in a compact WLAN PCMCIA board based on MAC and baseband ASIC chips designed from us.
Abstract: This study aims to investigate empirically the valuerelevance
of accounting information to domestic investors in Tehran
stock exchange from 1999 to 2006. During the present research
impacts of two factors, including positive vs. negative earnings and
the firm size are considered as well. The authors used earnings per
share and annual change of earnings per share as the income
statement indices, and book value of equity per share as the balance
sheet index. Return and Price models through regression analysis are
deployed in order to test the research hypothesis. Results depicted
that accounting information is value-relevance to domestic investors
in Tehran Stock Exchange according to both studied models.
However, income statement information has more value-relevance
than the balance sheet information. Furthermore, positive vs. negative
earnings and firm size seems to have significant impact on valuerelevance
of accounting information.
Abstract: In recent years, it has been proposed security
architecture for sensor network.[2][4]. One of these, TinySec by Chris
Kalof, Naveen Sastry, David Wagner had proposed Link layer security
architecture, considering some problems of sensor network. (i.e :
energy, bandwidth, computation capability,etc). The TinySec employs
CBC_mode of encryption and CBC-MAC for authentication based on
SkipJack Block Cipher. Currently, This TinySec is incorporated in the
TinyOS for sensor network security.
This paper introduces TinyHash based on general hash algorithm.
TinyHash is the module in order to replace parts of authentication and
integrity in the TinySec. it implies that apply hash algorithm on
TinySec architecture. For compatibility about TinySec, Components
in TinyHash is constructed as similar structure of TinySec. And
TinyHash implements the HMAC component for authentication and
the Digest component for integrity of messages. Additionally, we
define the some interfaces for service associated with hash algorithm.
Abstract: Flow field around hypersonic vehicles is very
complex and difficult to simulate. The boundary layers are squeezed
between shock layer and body surface. Resolution of boundary layer,
shock wave and turbulent regions where the flow field has high
values is difficult of capture. Detached eddy simulation (DES) is a
modification of a RANS model in which the model switches to a
subgrid scale formulation in regions fine enough for LES
calculations. Regions near solid body boundaries and where the
turbulent length scale is less than the maximum grid dimension are
assigned the RANS mode of solution. As the turbulent length scale
exceeds the grid dimension, the regions are solved using the LES
mode. Therefore the grid resolution is not as demanding as pure LES,
thereby considerably cutting down the cost of the computation. In
this research study hypersonic flow is simulated at Mach 8 and
different angle of attacks to resolve the proper boundary layers and
discontinuities. The flow is also simulated in the long wake regions.
Mesh is little different than RANS simulations and it is made dense
near the boundary layers and in the wake regions to resolve it
properly. Hypersonic blunt cone cylinder body with frustrum at angle
5o and 10 o are simulated and there aerodynamics study is performed
to calculate aerodynamics characteristics of different geometries. The
results and then compared with experimental as well as with some
turbulence model (SA Model). The results achieved with DES
simulation have very good resolution as well as have excellent
agreement with experimental and available data. Unsteady
simulations are performed for DES calculations by using duel time
stepping method or implicit time stepping. The simulations are
performed at Mach number 8 and angle of attack from 0o to 10o for
all these cases. The results and resolutions for DES model found
much better than SA turbulence model.
Abstract: The development of the power electronics has allowed
increasing the precision and reliability of the electrical trainings,
thanks to the adjustable inverters, as the Pulse Wide Modulation
(PWM) five level inverters, which is the object of study in this
article.The authors treat the relation between the law order adopted for
a given system and the oscillations of the electrical and mechanical
parameters of which the tolerance depends on the process with which
they are integrated (paper factory, lifting of the heavy loads,
etc.).Thus the best choice of the regulation indexes allows us to
achieve stability and safety training without investment (management
of existing equipment).
Abstract: As is needless to say; a majority of accidents, which occur, are due to drunk driving. As such, there is no effective mechanism to prevent this. Here we have designed an integrated system for the same purpose. Alcohol content in the driver-s body is detected by means of an infrared breath analyzer placed at the steering wheel. An infrared cell directs infrared energy through the sample and any unabsorbed energy at the other side is detected. The higher the concentration of ethanol, the more infrared absorption occurs (in much the same way that a sunglass lens absorbs visible light, alcohol absorbs infrared light). Thus the alcohol level of the driver is continuously monitored and calibrated on a scale. When it exceeds a particular limit the fuel supply is cutoff. If the device is removed also, the fuel supply will be automatically cut off or an alarm is sounded depending upon the requirement. This does not happen abruptly and special indicators are fixed at the back to avoid inconvenience to other drivers using the highway signals. Frame work for integration of sensors and control module in a scalable multi-agent system is provided .A SMS which contains the current GPS location of the vehicle is sent via a GSM module to the police control room to alert the police. The system is foolproof and the driver cannot tamper with it easily. Thus it provides an effective and cost effective solution for the problem of drunk driving in vehicles.
Abstract: In this paper, a class of impulsive BAM fuzzy cellular neural networks with time delays in the leakage terms is formulated and investigated. By establishing a delay differential inequality and M-matrix theory, some sufficient conditions ensuring the existence, uniqueness and global exponential stability of equilibrium point for impulsive BAM fuzzy cellular neural networks with time delays in the leakage terms are obtained. In particular, a precise estimate of the exponential convergence rate is also provided, which depends on system parameters and impulsive perturbation intention. It is believed that these results are significant and useful for the design and applications of BAM fuzzy cellular neural networks. An example is given to show the effectiveness of the results obtained here.
Abstract: A serious problem on the WWW is finding reliable
information. Not everything found on the Web is true and the
Semantic Web does not change that in any way. The problem will be
even more crucial for the Semantic Web, where agents will be
integrating and using information from multiple sources. Thus, if an
incorrect premise is used due to a single faulty source, then any
conclusions drawn may be in error. Thus, statements published on
the Semantic Web have to be seen as claims rather than as facts, and
there should be a way to decide which among many possibly
inconsistent sources is most reliable. In this work, we propose a trust
model for the Semantic Web. The proposed model is inspired by the
use trust in human society. Trust is a type of social knowledge and
encodes evaluations about which agents can be taken as reliable
sources of information or services. Our proposed model allows
agents to decide which among different sources of information to
trust and thus act rationally on the semantic web.
Abstract: Bioinformatics methods for predicting the T cell
coreceptor usage from the array of membrane protein of HIV-1 are
investigated. In this study, we aim to propose an effective prediction
method for dealing with the three-class classification problem of
CXCR4 (X4), CCR5 (R5) and CCR5/CXCR4 (R5X4). We made
efforts in investigating the coreceptor prediction problem as follows: 1)
proposing a feature set of informative physicochemical properties
which is cooperated with SVM to achieve high prediction test
accuracy of 81.48%, compared with the existing method with
accuracy of 70.00%; 2) establishing a large up-to-date data set by
increasing the size from 159 to 1225 sequences to verify the proposed
prediction method where the mean test accuracy is 88.59%, and 3)
analyzing the set of 14 informative physicochemical properties to
further understand the characteristics of HIV-1coreceptors.
Abstract: The concepts of knowledge creation and innovation
have a strong relationship but this relationship has not been examined
systematically. This study examines the utilization of knowledge
creation processes of the Theory of Knowledge Creation in Higher
Education Institutions. These processes consist of socialization,
externalization, combination and internalization. This study suggests
that the utilization of these processes will give impacts on innovation
in academic performance. A cross-sectional study was conducted
using survey questionnaires to collect data of the utilization of
knowledge creation processes and classroom-s innovation. The
samples are Business Management students of a Malaysian Higher
Education Institution. The results of this study could help Higher
Education Institutions to enrich the learning process of students
through knowledge creation and innovation.
Abstract: The aim of the study was to investigate the possible
use of commercial Computational Fluid Dynamics (CFD) software in
the design process of a domestic gas boiler. Because of the limited
computational resources some simplifications had to be made in
order to contribute to the design in a reasonable timescale.
The porous media model was used in order to simulate the
influence of the pressure drop characteristic of particular elements of
a heat transfer system on the water-flow distribution in the system.
Further, a combination of CFD analyses and spread sheet
calculations was used in order to solve the flow distribution problem.
Abstract: Abovepresented work deals with the new scope of application of information and communication technologies for the improvement of the election process in the biased environment. We are introducing a new concept of construction of the information-communication system for the election participant. It consists of four main components: Software, Physical Infrastructure, Structured Information and the Trained Stuff. The Structured Information is the bases of the whole system and is the collection of all possible events (irregularities among them) at the polling stations, which are structured in special templates, forms and integrated in mobile devices.The software represents a package of analytic modules, which operates with the dynamic database. The application of modern communication technologies facilities the immediate exchange of information and of relevant documents between the polling stations and the Server of the participant. No less important is the training of the staff for the proper functioning of the system. The e-training system with various modules should be applied in this respect. The presented methodology is primarily focused on the election processes in the countries of emerging democracies.It can be regarded as the tool for the monitoring of elections process by the political organization(s) and as one of the instruments to foster the spread of democracy in these countries.
Abstract: Super-resolution is nowadays used for a high-resolution
image produced from several low-resolution noisy frames. In
this work, we consider the problem of high-quality interpolation of a
single noise-free image. Such images may come from different sources,
i.e., they may be frames of videos, individual pictures, etc. On
the other hand, in the encoder we apply a downsampling via
bidimen-sional interpolation of each frame, and in the decoder we
apply a upsampling by which we restore the original size of the
image. If the compression ratio is very high, then we use a
convolutive mask that restores the edges, eliminating the blur.
Finally, both, the encoder and the complete decoder are implemented
on General-Purpose computation on Graphics Processing Units
(GPGPU) cards. In fact, the mentioned mask is coded inside texture
memory of a GPGPU.
Abstract: This paper proposes a system to extract images from web pages and then detect the skin color regions of these images. As part of the proposed system, using BandObject control, we built a Tool bar named 'Filter Tool Bar (FTB)' by modifying the Pavel Zolnikov implementation. The Yahoo! Team provides us with the Yahoo! SDK API, which also supports image search and is really useful. In the proposed system, we introduced three new methods for extracting images from the web pages (after loading the web page by using the proposed FTB, before loading the web page physically from the localhost, and before loading the web page from any server). These methods overcome the drawback of the regular expressions method for extracting images suggested by Ilan Assayag. The second part of the proposed system is concerned with the detection of the skin color regions of the extracted images. So, we studied two famous skin color detection techniques. The first technique is based on the RGB color space and the second technique is based on YUV and YIQ color spaces. We modified the second technique to overcome the failure of detecting complex image's background by using the saturation parameter to obtain an accurate skin detection results. The performance evaluation of the efficiency of the proposed system in extracting images before and after loading the web page from localhost or any server in terms of the number of extracted images is presented. Finally, the results of comparing the two skin detection techniques in terms of the number of pixels detected are presented.
Abstract: Steganography is the art of hiding and transmitting data
through apparently innocuous carriers in an effort to conceal the
existence of the data. A lot of steganography algorithms have been
proposed recently. Many of them use the digital image data as a carrier.
In data hiding scheme of halftoning and coordinate projection, still
image data is used as a carrier, and the data of carrier image are
modified for data embedding. In this paper, we present three features
for analysis of data hiding via halftoning and coordinate projection.
Also, we present a classifier using the proposed three features.
Abstract: Speech enhancement is the process of eliminating
noise and increasing the quality of a speech signal, which is
contaminated with other kinds of distortions. This paper is on
developing an optimum cascaded system for speech enhancement.
This aim is attained without diminishing any relevant speech
information and without much computational and time complexity.
LMS algorithm, Spectral Subtraction and Kalman filter have been
deployed as the main de-noising algorithms in this work. Since these
algorithms suffer from respective shortcomings, this work has been
undertaken to design cascaded systems in different combinations and
the evaluation of such cascades by qualitative (listening) and
quantitative (SNR) tests.
Abstract: An image compression method has been developed
using fuzzy edge image utilizing the basic Block Truncation Coding
(BTC) algorithm. The fuzzy edge image has been validated with
classical edge detectors on the basis of the results of the well-known
Canny edge detector prior to applying to the proposed method. The
bit plane generated by the conventional BTC method is replaced with
the fuzzy bit plane generated by the logical OR operation between
the fuzzy edge image and the corresponding conventional BTC bit
plane. The input image is encoded with the block mean and standard
deviation and the fuzzy bit plane. The proposed method has been
tested with test images of 8 bits/pixel and size 512×512 and found to
be superior with better Peak Signal to Noise Ratio (PSNR) when
compared to the conventional BTC, and adaptive bit plane selection
BTC (ABTC) methods. The raggedness and jagged appearance, and
the ringing artifacts at sharp edges are greatly reduced in
reconstructed images by the proposed method with the fuzzy bit
plane.