Vietnam Journal of Computer Science

This paper presents a survey of machine learning (ML) methods used in applications dedicated to the building and construction industry. A building information modeling (BIM) model, being a database system for civil engineering data, is presented. A representative selection of methods and applications is described. The aim of this paper is to facilitate the continuation of research efforts and to encourage bigger participation of database system researchers in the field of civil engineering.

Transfer-based attacks, a type of adversarial attack, have become a growing threat in recent years with the proliferation of cloud services. Deep neural networks that exploit human cognitive bias (Loosely Symmetric-Deep Neural Network, LS-DNN) are known as a defensive technique against transfer-based attacks. LS-DNN can prevent malfunctions caused by adversarial examples with a high probability by incorporating human learning characteristics into the neural network’s nodes. However, maintaining accuracy against normal data and reducing Training Time is challenging. This paper proposes a new model called “LS⁺-DNN” inspired by the Dropout method to solve this problem. Evaluation experiments on two datasets show that the proposed model can achieve both in high dimensions. In addition, we analyze the proposed model focusing on the variance and confidence score of the training parameters of the proposed model. As a result, we point out that the confidence score is an important indicator of robust models against transfer-based attacks.

This paper first presents six (6) types of benchmark amplitude design specifications, including variable low-pass specification, variable high-pass specification, variable bandpass specification, variable bandstop specification, variable notch-frequency specification, and variable notch-width specification. The design specifications can be taken as typical benchmark specifications targeted at testing as well as validating the effectiveness of various newly developed algorithms for designing various typical variable filters (VFs). Then, the paper provides a novel unity-bounded (UB) function developed for ensuring the stability of those VFs with recursive structures. Finally, a wide variety of simulation results are included for validating the design performance as well as the assured stability by using both the benchmark design specifications and the novel UB function.

Domain adaptation in neural machine translation (NMT) tasks often involves working with datasets that have a different distribution from the training data. In such scenarios, k-nearest-neighbor machine translation (kNN-MT) has been shown to be effective in retrieving relevant information from large datastores. However, the high-dimensional context vectors of large neural machine translation model result in high computational costs for distance computation and storage. To address this issue, index optimization techniques have been proposed, including the use of inverted file index (IVF) and product vector quantization (PQ), called IVFPQ. In this paper, we explore the recent index techniques for efficient machine translation domain adaptation and combine multiple index structures to improve the efficiency of nearest-neighbor search in domain adaptation datasets for machine translation task. Specifically, we evaluate the effectiveness when combining optimized product quantization (OPQ) and hierarchical navigable small-world (HNSW) indexing with IVFPQ. Our study aims to provide insights into the most suitable composite index methods for efficient nearest-neighbor search in domain adaptation datasets, with a focus on improving both accuracy and speed.

This study proposes a discrete mathematical Susceptible–Exposed–Preinfectious–Infectious–Recovered (SEPIR) states model for seasonal influenza. In a previous study, focusing on infections by preinfectious people using preexisting data, the author showed that the super-spreading of seasonal influenza occurred before the day that the first patients were discovered (D-day). In addition, when people do not take precautionary measures, the infectivity rate (from preinfected people) was determined as 0.041. After D-day in the community, the implementation of countermeasures was observed to reduce the infectivity rate to 0.002 and 0.013 in working and living spaces, respectively. The number of infectious people can be estimated by summing up each group in the community. This study performed a multiagent simulation (MAS) of seasonal influenza from preinfectious people in closed spaces based on decomposability. Then, the basic simulation is validated and the appropriateness of infective rates, changed infectivity rates, and near decomposability is confirmed.

Adrenal lesions refer to abnormalities or growths that occur in the adrenal glands, which are located on top of each kidney. These lesions can be benign or malignant and can affect the function of the adrenal glands. This paper presents a study on adrenal tumor segmentation using a modified U-Net model with various parameter selection strategies. The study investigates the effect of fine-tuning parameters, including k-fold values and batch sizes, on segmentation performance. Additionally, the study evaluates the effectiveness of different preprocessing techniques, such as Discrete Wavelet Transform (DWT), Contrast Limited Adaptive Histogram Equalization (CLAHE), and Image Fusion, in enhancing segmentation accuracy. The results show that the proposed model outperforms the original U-Net model, achieving the highest scores for Dice, Jaccard, sensitivity, and specificity scores of 0.631, 0.533, 0.579, and 0.998, respectively, on the T1-weighted dataset with DWT applied. These results highlight the importance of parameter selection and preprocessing techniques in improving the accuracy of adrenal tumor segmentation using deep learning.

Sentiment Analysis (SA) has attracted increasing research attention in recent years. Most existing works tackle the SA task by fine-tuning single pre-trained language models combined with specific layers. Despite their effectiveness, the previous studies overlooked the utilization of feature representations from various contextual language models. Ensemble learning techniques have garnered increasing attention within the field of Natural Language Processing (NLP). However, there is still room for improvement in ensemble models for the SA task, particularly in the aspect-level SA task. Furthermore, the utilization of heterogeneous ensembles, which combine various pre-trained transformer-based language models, may prove beneficial in enhancing overall performance by incorporating diverse linguistic representations. This paper introduces two ensemble models that leverage soft voting and feature fusion techniques by combining individual pre-trained transformer-based language models for the SA task. The latest transformer-based models, including PhoBERT, XLM, XLM-Align, InfoXLM, and viBERT_FPT, are employed to integrate knowledge and representations using feature fusion and a soft voting strategy. We conducted extensive experiments on various Vietnamese benchmark datasets, encompassing sentence-level, document-level, and aspect-level SA. The experimental results demonstrate that our approaches outperform most existing methods, achieving new state-of-the-art results with F1-weighted scores of 94.03%, 95.65%, 75.36%, and 76.23% on the UIT_VSFC, Aivivn, UIT_ABSA for the restaurant domain, and UIT_ViSFD datasets, respectively.