Steps to become a professional engineer in Malaysia

The book presents systematic guidelines for becoming a professional engineer (PEng) through the Institution of Engineers Malaysia (IEM) Route C (Corporate Member of IEM). The book 'Professional Engineer: A Step-by-step guide' is dedicated to engineers who aim to successfully apply to professional engineers in Malaysia. The content is comprehensive and covers application submission through Route C until registration as a professional engineer with the Board of Engineers Malaysia (BEM)

Powering wireless sensor networks with solar generated RF

Powering Wireless sensor networks (WSN) is one of the most researched topics in the wireless field. Due to the density of such networks, conventional power sourcing using wires is not feasible. Furthermore, a sensor node (SN) in a WSN consumes small amounts of energy. Therefore, the SN can be charged wirelessly using a radio frequency (RF) power transmitter. This paper presents a solar-powered simultaneous wireless information and power transfer (SWIPT) transmitter design with dynamic power allocation (DPA). Moreover, a receiver design with separate energy harvesting (EH) and information decoding (ID) circuitries is adopted. DPA carries the communication signal on low-power subcarriers around the carrier frequency, while the energy signal is carried on a highpower continuous wave (CW) centered at the carrier frequency. DPA reduces the interference to external networks by limiting the high power signal to a few subcarriers. Furthermore, the split receiver design increases the harvested power at the EH circuit reservoir

Multilayer hairpin bandpass filter for digital broadcasting / Robi'atun Adayiah Awang … [et al.]

A design of multilayer hairpin bandpass filter at digital broadcasting frequency has been presented. This filter has been presented based on the design specification together with the analyses of the response on the parameter sweeps of coupling gap, width and length of the resonators, metal thickness, substrate thickness and the measurement result of the fabricated circuit. This research has proposed 2.45-2.53 GHz bandpass filter using hairpin resonator in multilayer configuration for digital broadcasting application. The four-pole hairpin resonators centered at 2.5 GHz with bandwidth less than 100 MHz were designed. The best return and insertion losses in the passband are -42.96 dB and -2.55 dB, respectively. Combination of hairpin resonator operating at desired frequency has been optimized and simulated on Flame Retardant 4 (FR-4) with dielectric constant 4.6 together with the analysis using Computer Simulation Technology (CST). Design filter has been fabricated and measured using Network Analyzer and have a good agreement with simulated response. The measurement results of Sn and S21 obtained from the fabricated circuit are -19.56 dB and -7.64 dB, respectively. The analyses have proven that the design work according to the microwave theory. In addition it was observed that a wider bandwidth was achieved by increasing the number of resonators

Solar Activity and Seismicity

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太陽活動と地震

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Application of solar quiet (Sq) current in determining mantle conductivity-depth structure in Malaysia

The mantle electrical conductivity-depth structure of Malaysia was determined for the first time using solar quiet day ionospheric current (Sq) variations. Spherical harmonic analysis (SHA) was employed to separate the external and internal field contribution to the Sq variations. A transfer function was applied in estimating the conductivity-depth profile for the paired of external and internal coefficients of the SHA. We observed a downward increase in electrical conductivity with initial magnitude of 0.0065 S/m at a depth of ∼ 56 km which gradually rose to 0.0106 and 0.0140 S/m at 118 and 180 km. Subsequently, the conductivity profile rose to about 0.0228 S/m at 380 km (near the base of the upper mantle) and reached 0.0260 S/m at 435 km, after which a sharp steep increase was observed at 450 km with conductivity profile of 0.0278 S/m. Consequently, the conductivity profile increases significantly to about 0.1367 S/m at a depth of 973 km and reached its peak value 0.1975 S/m at the depth of 1097 km in the lower mantle with no indication of leveling off. An evidence of discontinuity was observed near 390–460 km and 675–746 km. A slight increase in conductivity values at depth between 150 and 300 km corresponds to the region of unusual global low velocity zone with high electrical conductivity. The conductivity profile showed a less steep increase above 450 km below which a steep increase was observed. The present profile showed the deepest penetration depth which may be attributed to the influence of equatorial electrojet current (EEJ) that is actively supported by the conductive properties of the Earth's interior within the study region. © 2018 Elsevier Lt

A Survey on Handover and Mobility Management in 5G HetNets: Current State, Challenges, and Future Directions

Fifth-generation (5G) networks offer high-speed data transmission with low latency, increased base station volume, improved quality of service (QoS), and massive multiple-input–multiple-output (M-MIMO) channels compared to 4G long-term evolution (LTE) networks. However, the COVID-19 pandemic has disrupted the achievement of mobility and handover (HO) in 5G networks due to significant changes in intelligent devices and high-definition (HD) multimedia applications. Consequently, the current cellular network faces challenges in propagating high-capacity data with improved speed, QoS, latency, and efficient HO and mobility management. This comprehensive survey paper specifically focuses on HO and mobility management issues within 5G heterogeneous networks (HetNets). The paper thoroughly examines the existing literature and investigates key performance indicators (KPIs) and solutions for HO and mobility-related challenges while considering applied standards. Additionally, it evaluates the performance of current models in addressing HO and mobility management issues, taking into account factors such as energy efficiency, reliability, latency, and scalability. Finally, this paper identifies significant challenges associated with HO and mobility management in existing research models and provides detailed evaluations of their solutions along with recommendations for future research

Comparison of UMi, UMa, and RMa Path Loss Models of 5G mmWave Communication System

The signal power in wireless communication systems is influenced by its surroundings; primarily, it will be affected by the path difference, operating frequency, and environmental effects. This makes it extremely challenging to plan any communication system that will provide better signal strength. Therefore, large-scale path loss models are considered to estimate the path loss at various frequencies, distances, and in various environments. In this paper, we considered UMi, UMa, and RMa environments to estimate the LOS and NLOS path loss for frequencies from 0.5 to 100 GHz. In the millimeter wave frequency range, a comparison is made between the path loss observed and the path loss models created by different standard organizations. The simulation results demonstrate that the 5GCM model is an optimized path loss model in the urban micro-environment, similarly 3GPP model is an optimized path loss model in UMa and RMa environments. These optimized models produce enhanced path loss compared to the other path loss models. These optimized models could be used by the service providers to enhance the quality of service in 5G wireless networks