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Sutrisno

Publications and source records attributed to Sutrisno.

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Realization of High Frequency Bidirectional Transceiver (Bitx) Radio

In this paper, we realize the transmitter of high frequency (HF) bidirectional transceiver radio. A bidirectional transceiver (Bitx) consists of a transmitter and receiver, in which some common circuits are used together by the transmitter and receiver. In addition, Bitx radio uses a single conversion superheterodyne transmitter, which only shifts frequency once in a signal generation process. The measurement result shows that it works at the frequency of 6.8 MHz with 10 MHz BFO, 3,2 MHz VFO, and 50,3 dBm transmit power. The transmitting frequency is obtained from the difference between BFO and VFO oscillator. Bitx radio has a simple circuit and is designed with low-cost components, and it could be an alternative solution for communication in remote areas.

cs.NI

Mask Usage Recognition using Vision Transformer with Transfer Learning and Data Augmentation

The COVID-19 pandemic has disrupted various levels of society. The use of masks is essential in preventing the spread of COVID-19 by identifying an image of a person using a mask. Although only 23.1% of people use masks correctly, Artificial Neural Networks (ANN) can help classify the use of good masks to help slow the spread of the Covid-19 virus. However, it requires a large dataset to train an ANN that can classify the use of masks correctly. MaskedFace-Net is a suitable dataset consisting of 137016 digital images with 4 class labels, namely Mask, Mask Chin, Mask Mouth Chin, and Mask Nose Mouth. Mask classification training utilizes Vision Transformers (ViT) architecture with transfer learning method using pre-trained weights on ImageNet-21k, with random augmentation. In addition, the hyper-parameters of training of 20 epochs, an Stochastic Gradient Descent (SGD) optimizer with a learning rate of 0.03, a batch size of 64, a Gaussian Cumulative Distribution (GeLU) activation function, and a Cross-Entropy loss function are used to be applied on the training of three architectures of ViT, namely Base-16, Large-16, and Huge-14. Furthermore, comparisons of with and without augmentation and transfer learning are conducted. This study found that the best classification is transfer learning and augmentation using ViT Huge-14. Using this method on MaskedFace-Net dataset, the research reaches an accuracy of 0.9601 on training data, 0.9412 on validation data, and 0.9534 on test data. This research shows that training the ViT model with data augmentation and transfer learning improves classification of the mask usage, even better than convolutional-based Residual Network (ResNet).

cs.CV