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1

Empirical Study of the Evolution of Python Questions on Stack Overflow

Syam Gopika, Lal Sangeeta, Chen Tao

e-Informatica Software Engineering Journal

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2023

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Vol. 17, nr 1

art. no. 230107

EN

Background: Python is a popular and easy-to-use programming language. It is constantly expanding, with new features and libraries being introduced daily for a broad range of applications. This dynamic expansion needs a robust support structure for developers to effectively utilise the language. Aim: In this study we conduct an in-depth analysis focusing on several research topics to understand the theme of Python questions and identify the challenges that developers encounter, using the questions posted on Stack Overflow. Method:We perform a quantitative and qualitative analysis of Python questions in Stack Overflow. Topic Modelling is also used to determine the most popular and difficult topics among developers. Results: The findings of this study revealed a recent surge in questions about scientific computing libraries pandas and TensorFlow. Also, we observed that the discussion of Data Structures and Formats is more popular in the Python community, whereas areas such as Installation, Deployment, and IDE are still challenging. Conclusion: This study can direct the research and development community to put more emphasis on tackling the actual issues that Python programmers are facing.

2

A Multi-Layer Micro-Perforated Panel Structure Based on Curled Space for Broadband Sound Absorption at Low Frequencies

Chu Jiaming, Liang Xiao, Yang Zhen, Liang Haofeng, Chen Tao, Su Liang, Zhou Zhuo

Archives of Acoustics

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2023

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Vol. 48, No. 4

529--538

EN

In this paper, we propose a multi-layer micro-perforated panel structure based on a curled space for broadband sound absorption at low frequencies, which increases the number of perforated panel layers in a limited space using a curled space. The absorption coefficients of the structure under plane wave conditions were calculated using the transfer matrix method and the finite element method. It is demonstrated that the multilayer micro-perforated panel structure can ensure high absorption (consistently over 90%) in the frequency range of 400~5000 Hz. The sound absorption mechanism of the multi-layer micro-perforated panel structure is investigated by using the acoustic impedance along with the reflection coefficient of the complex frequency surface. In addition, we also discuss the effects of the micro-perforated panel parameters on the structural sound absorption coefficient. The results show that the proposed multi-layer micro-perforated panel structure provides an excellent solution for sound absorption in a limited space.

3

C-V2X Communications for the Support of a Green Light Optimized Speed Advisory (GLOSA) Use Case

Chochliouros Ioannis P., Spiliopoulou Anastasia S., Kostopoulos Alexandros, Agapiou George, Lazaridis Pavlos, Zaharis Zaharias, Chen Tao, Dardamanis Athanassios, Kourtis Michail-Alexandros, Agapiou Marinos, Herzog Uwe, Ladid Latif

Journal of Telecommunications and Information Technology

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2021

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nr 2

93--106

EN

Rapid expansion of 5G affects a number of sectors, including vehicular communications relying on cooperative intelligent transportation systems (C-ITS). More specifically, in the context of the Internet of Vehicles (IoV), a particular emphasis is placed on modern cellular V2X (C-V2X) technologies aiming to further improve road safety. This work originates from the detailed scope of the ongoing 5G-DRIVE research project promoting cooperation between the EU and China, with the aim of demonstrating IoV services that rely on vehicle-to-infrastructure (V2I) communications. With the C-V2X approach serving as a point of departure, we analyze and describe a specific green light-optimized speed advisory (GLOSA) use case, for which we provide a detailed descriptive framework, a proposed architectural framework for trials, as well as specific KPIs for the joint assessment of trials between the EU and China. We also discuss the context for performance test procedures to be conducted as part of the intended trials. GLOSA provides end-users with short-term information on upcoming traffic light status to optimize traffic flows, help prevent speed limit violations, improve fuel efficiency, and reduce pollution.

4

Gene prediction by the noise-assisted MEMD and wavelet transform for identifying the protein coding regions

Zheng Qian, Chen Tao, Zhou Wenxiang, Xie Lei, Su Hongye

Biocybernetics and Biomedical Engineering

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2021

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Vol. 41, no. 1

196--210

EN

The analysis of protein coding regions of DNA sequences is one of the most fundamental applications in bioinformatics. A number of model-independent approaches have been developed for differentiating between the protein-coding and non-protein-coding regions of DNA. However, these methods are often based on univariate analysis algorithms, which leads to the loss of joint information among four nucleotides of DNA. In this article, we introduce a method on basis of the noise-assisted multivariate empirical mode decomposition (NA-MEMD) and the modified Gabor-wavelet transform (MGWT). The NA-MEMD algorithm, as a multivariate analysis tool, is utilized to reconstruct the numerical analyzed sequence since it enables a matched-scale decomposition across all variables and eliminates the mode mixing. By virtues of NA-MEMD, the MGWT method achieves a stable improvement on the general identification performance. We compare our method with other Digital Signal Processing (DSP) methods on two representative DNA sequences and three benchmark datasets. The results reveal that our method can enhance the spectra of the analyzed sequences, and improve the robustness of MGWT to different DNA sequences, thus obtaining higher identification accuracies of protein coding regions over other applied methods. In addition, another comparative experiment with the model-dependent method (AUGUSTUS) on the recently proposed benchmark dataset G3PO verifies the superiority of model-independent methods (especially NA-MEMD-MGWT) for identifying coding regions of the poor-quality DNA sequences.

5

Study on separation of fine-particle ilmenite and mechanism using flocculation flotation with sodium oleate and polyacrylamide

Peng Yang, Xiao Junhui, Deng Bing, Wang Zhen, Liu Nengyun, Yang Daoguang, Ding Wei, Chen Tao, Wu Qiang

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 1

161--172

EN

In this paper, sodium oleate, polyacrylamide, soluble starch and sodium carboxymethyl cellulose were used as flocculants to study the flocculation and sedimentation behavior of microfine ilmenite. Sedimentation test shows that sodium oleate and polyacrylamide have good flocculation effect on ultrafine ilmenite. The flocculation rate of ilmenite can be further improved by the combination of sodium oleate and polyacrylamide. It was found that both flocculants could generate chemical adsorption with ilmenite surface, and they all react with Fe3+ on ilmenite surface. However, sodium oleate reacts with Fe3+ to form a water-insoluble iron oleate precipitate which coats the surface of the ilmenite and hinders the action of polyacrylamide and the remaining Fe3+. This problem can be avoided by adding polyacrylamide followed by sodium oleate, and the flotation recovery can be increased significantly.

6

A novel process for extraction of iron from a refractory red mud

Ding Wei, Xiao Junhui, Peng Yang, Shen Siyue, Chen Tao, Zou Kai, Wang Zhen

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 6

125--136

EN

Red mud is a kind of solid waste produced during alumina extraction from bauxite. To extraction valuable iron from red mud, the technology of adding sodium sulfate-segregation roasting-magnetic separation to treat red mud was developed. During the paper, the effects of various process parameters on the extraction of iron by segregation roasting-magnetic separation were studied, and the phase transformation behavior and microstructure of iron are explored. Repeated test results showed that magnetic concentrate (mass percent), TFe of 80.29 % and overall iron recovery of 92.08 %was obtained. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) results indicated that after the segregation roasting, the hematite was transformed into a new metal phase consisting mainly of metallic iron and magnetite. The addition of sodium sulfate during the segregation roasting can obviously improve the efficiency of segregation roasting-magnetic separation for iron extraction.

7

Harmonic mitigation in 18-pulse rectifier based on zigzag autotransformer by DC side auxiliary circuit

Liu Jiongde, Chen Xiaoqiang, Wang Ying, Chen Tao

Archives of Electrical Engineering

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2020

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Vol. 69, nr 4

891--905

EN

To improve the power quality of a multi-pulse rectifier, a zigzag 18-pulse uncontrolled rectifier with an auxiliary circuit at the DC side is proposed. When the grid-side currents are sinusoidal waves, the required DC side injection currents to be compensated can be obtained by analyzing the AC-DC side relationship of diode bridge rectifiers. Then the 6 compensation currents generated by an active auxiliary circuit are injected into the DC side to eliminate the grid-side harmonics of the rectifier. The simulation results verifying the correctness of the theoretical analysis show that the proposed rectifier can mitigate the harmonic content, as the total harmonic distortion of the grid-side current is about 1.45%. In addition, the single-phase inverter used in the active auxiliary circuit has the characters of simple circuit structure and easy controllability.

8

Design and Analysis of Ultrasonic Composite Transducer with a Quarter-wave Taper Transition Horn

Chen Tao, Li Hongbo, Wang Qihan, Ye Junpeng

Archives of Acoustics

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2020

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Vol. 45, No. 4

687--697

EN

Based on the electromechanical equivalent circuit theory, equations related to the resonance frequency and the magnifying coefficient of a quarter-wave vibrator and a quarter-wave taper transition horn were deduced, respectively. A series of 3D models of ultrasonic composite transducers with various conical section length was also established. To reveal the influences of the conical section length and the prestressed bolt on the dynamic characteristics (resonance frequency, amplitude, displacement node, and the maximum equivalent stress) of the models and the design accuracy, finite element (FE) analyses were carried out. The results show that the addition of prestressed bolt increases the resonance frequency and causes the displacement node on the center axis to move towards the small cylindrical section. As the conical section length rises, the increment of resonance frequency reduces and tends to a stable value of 360 Hz while the displacement of the node on the center axis becomes lager and gradually approaches 1.5 mm. Furthermore, the amplitude of the output terminal is stable at 16.18 µm under 220 V peak-topeak (77.8 VRMS) sinusoidal potential excitation. After that, a prototype was fabricated and validated experiments were conducted. The experimental results are consistent with that of theory and simulations. It provides theoretical basis for the design and optimization of small-size, large-amplitude, and high-power composite transducers.

9

Efficient separation of five flavonoids from Oxytropis falcata bunge by high-speed counter-current chromatography and their anticancer activity

Chen Chen, Liu Fengqin, Zhao Jingyang, Chen Tao, Li Yulin, Zhang Dejun

Acta Chromatographica

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2020

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Vol. 32, no. 3

189--193

EN

Oxytropis falcata Bunge, known as the “king of herbs” in Tibetan medicine, is used for treatment of hyperpyrexia, pain, wounds, inflammation, and anthrax. However, it is difficult to efficiently isolate compounds with high purity from O. falcata because of the complexity of traditional Tibetan medicines. In this study, the 80% ethanol elution fraction from extract by AB-8 macroporous resin column chromatography was demonstrated to have anticancer activity on human hepatoma SMMC-7721 cells in vitro. Then, a high-speed counter-current chromatography (HSCCC) method was successfully established for separation of compounds by using hexane–ethyl acetate–methanol–water (10:4:10:10, v/v/v/v) as the solvent system. Five flavonoids (7-hydroxyflavonone [1], 5,7-dihydroxy-4′-methoxy flavonol [2], 5,7-dihydroxyflavanone [3], 2′,4′-dihydroxychalcone [4], and 2′,4′-dihydroxydihydrochalcone [5]) were obtained in one-step separation with purities of 97.7%, 98.1%, 98.3%, 99.0%, and 98.3%, respectively. Finally, anticancer activities against the growth of SMMC-7721 cells of 5 flavonoids were confirmed. The IC50 values of the separated compounds were 213.45 μg/mL, 197.74 μg/mL, 375.16 μg/mL, 17.44 μg/mL, and 136.83 μg/mL in 24 h, respectively. The present study provided a basis for further development and utilization of this medicinal herb as a source of a new potential anticancer agent.