Abstract: This paper presents the experimental results on space charge distribution in cross-linked polyethylene (XLPE) insulating material for 22 kV power distribution system cable by using pulse electroacoustic measurement technique (PEA). Numbers of XLPE insulating material ribbon having thickness 60 μm taken from unused 22 kV high voltage cable were used as specimen in this study. DC electric field stress was applied to test specimen at room temperature (25°C). Four levels of electric field stress, 25 kV/mm, 50 kV/mm, 75 kV/mm and 100 kV/mm, were used. In order to investigate space charge distribution characteristic, space charge distribution characteristics were measured after applying electric field stress 15 min, 30 min and 60 min, respectively. The results show that applied time and magnitude of dc electric field stress play an important role to the formation of space charge.
Abstract: This paper presents the 20-GHz fractional PLL (Phase
Locked Loop) circuit for the next generation Wi-Fi by using 90 nm
TSMC process. The newly suggested millimeter wave 16/17
pre-scalar is designed and verified by measurement to make the
fractional PLL having a low quantization noise. The operational
bandwidth of the 60 GHz system is 15 % of the carrier frequency
which requires large value of Kv (VCO control gain) resulting in
degradation of phase noise. To solve this problem, this paper adopts
AFC (Automatic Frequency Controller) controlled 4-bit millimeter
wave VCO with small value of Kv. Also constant Kv is implemented
using 4-bit varactor bank. The measured operational bandwidth is 18.2
~ 23.2 GHz which is 25 % of the carrier frequency. The phase noise of
-58 and -96.2 dBc/Hz at 100 KHz and 1 MHz offset is measured
respectively. The total power consumption of the PLL is only 30 mW.
Abstract: This paper presents an automated inspection algorithm
for a thick plate. Thick plates typically have various types of surface
defects, such as scabs, scratches, and roller marks. These defects have
individual characteristics including brightness and shape. Therefore, it
is not simple to detect all the defects. In order to solve these problems
and to detect defects more effectively, we propose a dual light
switching lighting method and a defect detection algorithm based on
Abstract: This paper introduces a new instantaneous frequency
computation approach -Counting Instantaneous Frequency for a
general class of signals called simple waves. The classsimple wave
contains a wide range of continuous signals for which the concept
instantaneous frequency has a perfect physical sense. The concept of
-Counting Instantaneous Frequency also applies to all the discrete data.
For all the simple wave signals and the discrete data, -Counting
instantaneous frequency can be computed directly without signal
decomposition process. The intrinsic mode functions obtained through
empirical mode decomposition belongs to simple wave. So
-Counting instantaneous frequency can be used together with
empirical mode decomposition.
Abstract: The High Voltage (HV) transmission mains into the community necessitate earthing design to ensure safety compliance of the system. Concrete poles are widely used within HV transmission mains; which could have an impact on the earth grid impedance and input impedance of the system from the fault point of view. This paper provides information on concrete pole earthing to enhance the split factor of the system; further, it discusses the deployment of concrete structures in high soil resistivity area to reduce the earth grid system of the plant. This paper introduces the cut off soil resistivity SC ρ when replacing timber poles with concrete ones.
Abstract: This research paper designs a unique motion planner
of multiple platoons of nonholonomic car-like robots as a feasible
solution to the lane changing/merging maneuvers. The decentralized
planner with a leaderless approach and a path-guidance principle
derived from the Lyapunov-based control scheme generates collision
free avoidance and safe merging maneuvers from multiple lanes to a
single lane by deploying a split/merge strategy. The fixed obstacles
are the markings and boundaries of the road lanes, while the moving
obstacles are the robots themselves. Real and virtual road lane
markings and the boundaries of road lanes are incorporated into a
workspace to achieve the desired formation and configuration of the
robots. Convergence of the robots to goal configurations and the
repulsion of the robots from specified obstacles are achieved by
suitable attractive and repulsive potential field functions,
respectively. The results can be viewed as a significant contribution
to the avoidance algorithm of the intelligent vehicle systems (IVS).
Computer simulations highlight the effectiveness of the split/merge
strategy and the acceleration-based controllers.
Abstract: This paper discusses the investigation of a wearable
textile monopole antenna on specific absorption rate (SAR) for bodycentric
wireless communication applications at 2.45 GHz. The
antenna is characterized on a realistic 8 x 8 x 8 mm3 resolution
truncated Hugo body model in CST Microwave Studio software. The
result exhibited that the simulated SAR values were reduced
significantly by 83.5% as the position of textile monopole was
varying between 0 mm and 15 mm away from the human upper arm.
A power absorption reduction of 52.2% was also noticed as the
distance of textile monopole increased.
Abstract: The background estimation approach using a small
window median filter is presented on the bases of analyzing IR point
target, noise and clutter model. After simplifying the two-dimensional
filter, a simple method of adopting one-dimensional median filter is
illustrated to make estimations of background according to the
characteristics of IR scanning system. The adaptive threshold is used
to segment canceled image in the background. Experimental results
show that the algorithm achieved good performance and satisfy the
requirement of big size image-s real-time processing.
Abstract: A low cost Short Message System (SMS) based Home security system equipped with motion, smoke, temperature, humidity and light sensors has been studied and tested. The sensors are controlled by a microprocessor PIC 18F4520 through the SMS having password protection code for the secure operation. The user is able to switch light and the appliances and get instant feedback. Also in cases of emergencies such as fire or robbery the system will send alert message to occupant and relevant civil authorities. The operation of the home security has been tested on Vodafone- Fiji network and Digicel Fiji Network for emergency and feedback responses for 25 samples. The experiment showed that it takes about 8-10s for the security system to respond in case of emergency. It takes about 18-22s for the occupant to switch and monitor lights and appliances and then get feedback depending upon the network traffic.
Abstract: WOLED is widely used as lighting for high efficacy and little power consumption. In this research, power factor testing between WOLED and fluorescent lamp to see which one is more efficient in consuming energy. Since both lamps use semiconductor components, so calculation of the power factor need to consider the effects of harmonics. Harmonic make bigger losses. The study is conducted by comparing the value of the power factor regardless of harmonics (DPF) and also by included the harmonics (TPF). The average value of DPF of fluorescent is 0.953 while WOLED is 0.972. The average value of TPF of fluorescent is 0.717 whereas WOLED is 0.933. So from the review of power factor WOLED is more energy efficient than fluorescent lamp.
Abstract: An information procuring and processing emerging technology wireless sensor network (WSN) Consists of autonomous nodes with versatile devices underpinned by applications. Nodes are equipped with different capabilities such as sensing, computing, actuation and wireless communications etc. based on application requirements. A WSN application ranges from military implementation in the battlefield, environmental monitoring, health sector as well as emergency response of surveillance. The nodes are deployed independently to cooperatively monitor the physical and environmental conditions. The architecture of WSN differs based on the application requirements and focus on low cost, flexibility, fault tolerance capability, deployment process as well as conserve energy. In this paper we have present the characteristics, architecture design objective and architecture of WSN
Abstract: Antiseismic property of telecommunication equipment
is very important for the grasp of the damage and the restoration after
earthquake. Telecommunication business operators are regulating
seismic standard for their equipments. These standards are organized
to simulate the real seismic situations and usually define the minimum
value of first natural frequency of the equipments or the allowable
maximum displacement of top of the equipments relative to bottom.
Using the finite element analysis, natural frequency can be obtained
with high accuracy but the relative displacement of top of the
equipments is difficult to predict accurately using the analysis.
Furthermore, in the case of simulating the equipments with access
floor, predicting the relative displacement of top of the equipments
become more difficult.
In this study, using enormous experimental datum, an empirical
formula is suggested to forecast the relative displacement of top of the
equipments. Also it can be known that which physical quantities are
related with the relative displacement.
Abstract: Fatigue behaviors of Lead Zirconate Titanate (PZT)
ceramics under different amplitude of bipolar electrical loads have
been investigated. Fatigue behavior is represented by the change of
hysteresis loops and remnant polarization. Three levels of electrical
load amplitudes (1.00, 1.25 and 1.50 kV /mm) were applied in this
experimental. It was found that the remnant polarization decreased
significantly with the number of loading cycles. The degree of fatigue
degradation depends on the amplitude of electric field. The higher
amplitude exhibits the greater fatigue degradation.
Abstract: The demand on High voltage (HV) infrastructures is growing due to the corresponding growth in industries and population. New or upgraded HV infrastructure has safety implications since Transmission mains usually occupy the same easement in the vicinity of neighbouring residents. Transmission mains consist of underground (UG) and overhead (OH) sections and the transition between the UG and OH section is known as the UGOH pole. The existence of two transmission mains in the same easement can dictate to resort to more complicated earthing design in order to mitigate the effect of AC interference, and in some cases it can also necessitates completing a Split Study of the system. This paper provides an overview of the AC interference, Split Study and the earthing of an underground feeder including the UGOH pole .In addition, this paper discusses the use of different link boxes on the UG feeder and presents a case study that represent a clear example of the Ac interference and Split factor. Finally, a few recommendations are provided to achieve a safety zone in the area beyond the boundary of the HV system.
Abstract: Infrared focal plane arrays (IRFPA) sensors, due to
their high sensitivity, high frame frequency and simple structure, have
become the most prominently used detectors in military applications.
However, they suffer from a common problem called the fixed pattern
noise (FPN), which severely degrades image quality and limits the
infrared imaging applications. Therefore, it is necessary to perform
non-uniformity correction (NUC) on IR image. The algorithms of
non-uniformity correction are classified into two main categories, the
calibration-based and scene-based algorithms. There exist some
shortcomings in both algorithms, hence a novel non-uniformity
correction algorithm based on non-linear fit is proposed, which
combines the advantages of the two algorithms. Experimental results
show that the proposed algorithm acquires a good effect of NUC with
a lower non-uniformity ratio.
Abstract: An array antenna system with innovative signal
processing can improve the resolution of a source direction of arrival
(DoA) estimation. High resolution techniques take the advantage of
array antenna structures to better process the incoming waves. They
also have the capability to identify the direction of multiple targets.
This paper investigates performance of the DOA estimation
algorithm namely; Capon and MUSIC on the uniform linear array
(ULA). The simulation results show that in Capon and MUSIC
algorithm the resolution of the DOA techniques improves as number
of snapshots, number of array elements, signal-to-noise ratio and
separation angle between the two sources θ increases.
Abstract: In the present simulation work, an attempt is made to study the switching dynamics of an optically controlled 4HSiC thyristor power semiconductor device with the use of GaAs optically triggered power transistor. The half-cell thyristor has the forward breakdown of 200 V and reverse breakdown of more than 1000 V. The optically controlled thyristor has a rise time of 0.14 μs and fall time of 0.065 μs. The turn-on and turn-off delays are 0.1 μs and 0.06 μs, respectively. In addition, this optically controlled thyristor is used as a control switch for the DC-DC Boost converter. The pn-diode used for the converter has the forward drop of 2.8 V and reverse breakdown of around 400 V.
Abstract: An active RC filters with a 880 / 1760 MHz dual bandwidth tuning ability is present for 60 GHz unlicensed band applications. A third order Butterworth low-pass filter utilizes two Cherry-Hooper amplifiers to satisfy the very high bandwidth requirements of an amplifier. The low-pass filter is fabricated in 90nm standard CMOS process. Drawing 6.7 mW from 1.2 V power supply, the low frequency gains of the filter are -2.5 and -4.1 dB, and the output third order intercept points (OIP3) are +2.2 and +1.9 dBm for the single channel and channel bonding conditions, respectively.
Abstract: This paper present the harmonic elimination of hybrid
multilevel inverters (HMI) which could be increase the number of
output voltage level. Total Harmonic Distortion (THD) is one of the
most important requirements concerning performance indices.
Because of many numbers output levels of HMI, it had numerous
unknown variables of eliminate undesired individual harmonic and
THD nonlinear equations set. Optimized harmonic stepped waveform
(OHSW) is solving switching angles conventional method, but most
complicated for solving as added level. The artificial intelligent
techniques are deliberation to solve this problem. This paper presents
the Particle Swarm Optimization (PSO) technique for solving
switching angles to get minimum THD and eliminate undesired
individual harmonics of 15-levels hybrid multilevel inverters.
Consequently it had many variables and could eliminate numerous
harmonics. Both advantages including high level of inverter and
Particle Swarm Optimization (PSO) are used as powerful tools for
Abstract: This paper describes a three-dimensional thermal
model of the current path included in the low voltage power circuit
breakers. The model can be used to analyse the thermal behaviour of
the current path during both steady-state and transient conditions.
The current path lengthwise temperature distribution and timecurrent
characteristic of the terminal connections of the power circuit
breaker have been obtained. The influence of the electric current and
voltage drop on main electric contact of the circuit breaker has been
investigated. To validate the three-dimensional thermal model, some
experimental tests have been done. There is a good correlation
between experimental and simulation results.