Parameter estimation of complex exponential signals corrupted by additive white
Gaussian noise (AWGN) is crucial in the study of distributed beamforming in a practical
scenario. Near zero (0) phase offset are expected at the receiver end which rely on the
smoothing and correction of the frequency and phase estimates. Neither
computational complexity nor the processing latency has an effect on the expected
zero phase offset but the estimation accuracy does. Thus, the maximum likelihood
estimator (MLE) using Fast Fourier Transform (FFT) approach is being considered for
cases with none and post processing in locating of the maximum peaks. Details on how
the phase estimates are arrived at is not always covered in literatures but explained in
the article. Numerical results obtained showed that global maximum peaks are arrived
at by employing a fine search with higher values of FFT.
Flipped Classroom enables instructors to spend more time for hands-on problem-solving instruction compared to the traditional pedagogical model which involves lectures. The purpose of this study is to determine the need for a problem-solving flipped classroom module to be designed for the STM3023: Internet of Things (IoT) subject offered at the Certificate level at Malaysian Community Colleges. A structured interview was conducted with 16 lecturers from 14 Community Colleges offering the subject to obtain their views on current teaching practices along with the challenges faced in the teaching and learning of IoT to entry level students. Participants were also asked about their readiness towards the flipped classroom following an orientation session on Flipped Classroom approach. The findings showed that lecturers mostly used traditional pedagogical models in the TVET settings such as lectures. Students usually followed instructions and merely replicate the hands-on tasks as demonstrated by their lecturers in class. It was also found that students were struggling with the subject due to their lack of competency in programming and grasping electrical and electronics concepts. Students were also found to be weak in mathematics and reasoning skills, thus making it a challenge to teach IoT to them. Therefore, a myriad of media, materials and application of real-world concepts may be required to aid lecturers to improve students’ achievement in the subject. The flipped classroom approach for teaching which gives more time for hands-on problem-solving instruction may be appropriate to support lecturers to overcome the challenges in teaching IoT.
This paper reports the effect of microbending losses in single mode optical fiber
for pressure sensing system application. Several types of periodical corrugated
plates were fabricated, namely cylindrical-structured surface (Plate A) and
rectangular-structured surface (Plate B) with thicknesses of corrugated parts
were varied at 0.1 cm, 0.2 cm and 0.3 cm. Laser sources with excitation
wavelengths of 1= 1310 nm and 2= 1550 nm were launched at the first end
of the fiber. The values of losses were recorded by using an optical power
meter. It was clearly seen that the microbending losses were polynomially
increased with the increment of applied pressure and the thicknesses of
corrugated parts of Plate A and Plate B. The maximum microbending losses of
1.5185 dBm/kPa was resulted as SMF was coupled with corrugated plates B
with thicknesses of 0.3cm by using excitation wavelength of 1550nm. These
values reduced to 0.7628 dBm/kPa and 0.4014 dBm/kPa as the thicknesses
were decreased to 0.2cm and 0.1cm respectively. In comparison with a plain
plate which acted as a reference indicator, the maximum percentage of
microbending losses was obtained as 74.29 % for Plate A and 95.02 % for Plate
B. In conclusions, we successfully proved the ability of SMF as a pressure sensor
by manipulating the microbending losses experienced by the fiber. The
employment of 1550nm of laser wavelength results better sensitivity sensor
where the system able to detect large losses as the pressure applied on the
corrugated surfaces.
Laterite soils are occasionally associated with geotechnical problems such as road deformation, erosion, settlement, dam seepage, slope instability, leachate permeation through hydraulic barriers, etc. Numerous soil improvement techniques were being applied to overcome these problems, including mixing the laterite soil with cements, limes, bitumen, chemicals, pozzolanas, etc. These additives may not be locally available and cheap, and could significantly increase the cost of construction. Likewise, in many cases, these stabilizing agents are not environmentally friendly. Different percentages of fines, sand and gravel in laterite soils exhibit different engineering characteristics and behaviour, making it difficult to obtain suitable and appropriate gradation for specific construction purposes. Thus, the essence of this review is to determine the fundamental engineering properties of laterite soil as a standalone material at different gradations to harness its potentiality for various construction purposes. It proposes step-by-step procedures on how to achieve a better soil by varying its gradation and moisture content. Laboratory testing in accordance with BS1377:1990 and ASTM D698 are adopted to examine the engineering characteristics with respect to hydraulic conductivity, shear strength, and volumetric shrinkage. In this experimental technique where molding water content and compaction energy are carefully controlled at different laterite gradations, the engineering design is anticipated to provide greater accuracy, safety, and sustainability.