Developing E-Learning System to Support Visual Impairment During Covid-19 Pandemic

E-learning is a common tool to support the education in variety of scenarios. As the education content can be prepared by the group of specialists, but the skilled teachers are limited in remote area. Also, the contents in most curriculum are planned to distribute to limited skilled people. The gap of education can be full-filled with E- learning system. However, the conventional E-learning is high cost system and not appropriated for rural area. Also, opensource system is complicated to implement and configure in dedicated curriculum. This research is proposed the customized design of E-learning system for supporting visual impaired student with dynamic design during Covid-19 pandemic. The limitation has challenged the research to sharing and testing among the stakeholders. The system is designed and implemented from actual requirements from teachers and students in university level. As a result, the result show student involvement and deliver more content and knowledge to the visual impaired students. The feedback from actual usage also is evaluated.

The calculation of the field of an antenna located near the human head

In this work, a numerical calculation was carried out in one of the universal programs for automatic electro-dynamic design. The calculation is aimed at obtaining numerical values for specific absorbed power (SAR). It is the SAR value that can be used to determine the effect of the antenna of a wireless device on biological objects; the dipole parameters will be selected for GSM1800. Investigation of the influence of distance to a cell phone on radiation shows that absorbed in the head of a person the effect of electromagnetic radiation on the brain decreases by three times this is a very important result the SAR value has decreased by almost three times it is acceptable results.

Designing and performance investigation of permanent magnet motor prototype for UTV electric drive train application

<span lang="EN-US">The dynamic design specifications of a vehicle are used to define the required torque and speed of a permanent magnet motor. This is due to providing clear instructions on the intent, performance, and construction of a vehicle. Therefore, this study aims to determine an engineering design and prototyping process of a Permanent Magnet Motor, to be used as an electric powertrain in a Utility Vehicle. Based on being used in severe road condition (steep inclination and off road), the vehicle should be able to handle a 45° inclination with total payload of approximately 250 kg. Using a rear-wheel-drive traction, its weight should also be less than 1000 kg. Furthermore, the motor should be operated at a maximum battery voltage of 100 V. According to the requirements, the electric powertrain should further have the ability to deliver a torque of approximately 1600 Nm on both rear wheels. Using a finite element method to simulate performances, transmission was coupled to the motor in providing the required torque. In addition, the motor prototype was subsequently manufactured and tested using a dynamometer. The results showed that the motor produced 19.6 kW, 5600 RPM, and 75 Nm at 96 V. Therefore, the design and prototyping process of the motor satisfied all the required specification.</span>

Spectral analysis of the dry bulk shipping market by utilizing the system dynamics approach

PurposeThis research analyzes the cycle of the dry bulk shipping market (DBSM) as a representative of spot and period charter rates in dry bulk shipping to develop strategies for investment timing (i.e. asset play) and fleet trading (chartering strategy).Design/methodology/approachSpectral analysis is a numerical approach to extract significant cyclicality, which may be utilized to develop trading strategies. Instead of working with a single dataset (univariate), a system approach can be utilized to observe a significant shipping market cycle in its multi-variate circumstance. In this paper, a system dynamics design is employed to extract cyclicality in the DBSM in its particular industrial environment. The system dynamic design has competitive forecasting accuracy relative to univariate time series models and artificial neural networks (ANNs) in terms of forecasting outcomes.FindingsThe results show that the system dynamic design has a better forecasting performance according to three evaluation metrics, mean absolute scale error (MASE), root mean square error (RMSE) and mean absolute percentage error (MAPE).Originality/valueCyclical analysis is a significantly useful instrument for shipping asset management, particularly in market entry–exit operations. This paper investigated the cyclical nature of the dry bulk shipping business and estimated significant business cycle periodicity at around 4.5-year frequency (i.e. the Kitchin cycle).

Dynamic Design of the Test Bench of Electric Vehicle Motor

In order to avoid the resonance of the bench and the laboratory floor, it is necessary to carry out vibration analysis and dynamic design on the motor test bench. Firstly, the lightweight target and the constraint conditions related to the rigid body modal frequency and elastic modal frequency of the platform are set, and the structure of the platform is optimized. Then, the three-dimensional model of the whole bench is built and the finite element is meshed to carry out modal analysis. The optimized modal analysis results show that the natural frequencies of the designed bench will not be excited by various vibration excitation forces at the set speed of motor test, the vibration isolation rate of the lower bracket reaches more than 52% (except that the vibration isolation rate of the lower bracket is 36.30% at 1000 rpm), which effectively eliminates the resonance problem between the bench and foundation during motor NVH test, and the normal performance of motor and NVH test can be effectively ensured.

Representation of the kinematics of the natural trihedral of a spiral-helix trajectory by quaternion matrices

The spiral-helix trajectory of the transport vehicle programmed motion in the form of a hodograph in the stationary frame of reference is considered. A relative frame of reference associated with the natural trihedral of the trajectory is introduced. The formulas of curvature and torsion of the trajectory, the unit vector of the natural trihedral, the components of the angular velocity of rotation of the natural trihedral in the proper axes and in the stationary frame of reference are set in the quaternionic matrices. The results are verified using the Frenet-Serret formulas. The mathematical apparatus of quaternion matrices is tested with the aim of adapting spatial, nonlinear problems of dynamic design of transport vehicles to a computational experiment.