Pub Date : 2023-06-01DOI: 10.1051/wujns/2023283237
Huan Jin, Qinying Li
Smart contracts, which automatically execute on decentralized platforms like Ethereum, require high security and low gas consumption. As a result, developers have a strong demand for semantic code search tools that utilize natural language queries to efficiently search for existing code snippets. However, existing code search models face a semantic gap between code and queries, which requires a large amount of training data. In this paper, we propose a fine-tuning approach to bridge the semantic gap in code search and improve the search accuracy. We collect 80 723 different pairs of from Etherscan.io and use these pairs to fine-tune, validate, and test the pre-trained CodeBERT model. Using the fine-tuned model, we develop a code search engine specifically for smart contracts. We evaluate the Recall@k and Mean Reciprocal Rank (MRR) of the fine-tuned CodeBERT model using different proportions of the fine-tuned data. It is encouraging that even a small amount of fine-tuned data can produce satisfactory results. In addition, we perform a comparative analysis between the fine-tuned CodeBERT model and the two state-of-the-art models. The experimental results show that the fine-tuned CodeBERT model has superior performance in terms of Recall@k and MRR. These findings highlight the effectiveness of our fine-tuning approach and its potential to significantly improve the code search accuracy.
{"title":"Fine-Tuning Pre-Trained CodeBERT for Code Search in Smart Contract","authors":"Huan Jin, Qinying Li","doi":"10.1051/wujns/2023283237","DOIUrl":"https://doi.org/10.1051/wujns/2023283237","url":null,"abstract":"Smart contracts, which automatically execute on decentralized platforms like Ethereum, require high security and low gas consumption. As a result, developers have a strong demand for semantic code search tools that utilize natural language queries to efficiently search for existing code snippets. However, existing code search models face a semantic gap between code and queries, which requires a large amount of training data. In this paper, we propose a fine-tuning approach to bridge the semantic gap in code search and improve the search accuracy. We collect 80 723 different pairs of from Etherscan.io and use these pairs to fine-tune, validate, and test the pre-trained CodeBERT model. Using the fine-tuned model, we develop a code search engine specifically for smart contracts. We evaluate the Recall@k and Mean Reciprocal Rank (MRR) of the fine-tuned CodeBERT model using different proportions of the fine-tuned data. It is encouraging that even a small amount of fine-tuned data can produce satisfactory results. In addition, we perform a comparative analysis between the fine-tuned CodeBERT model and the two state-of-the-art models. The experimental results show that the fine-tuned CodeBERT model has superior performance in terms of Recall@k and MRR. These findings highlight the effectiveness of our fine-tuning approach and its potential to significantly improve the code search accuracy.","PeriodicalId":23976,"journal":{"name":"Wuhan University Journal of Natural Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46555816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1051/wujns/2023283185
Juan Lin
In this paper, a class of inverse boundary value problems for (λ, 1) bi-analytic functions is given. Using the method of Riemann boundary value problem for analytic functions, the conditions of solvability and the expression of the solutions for the inverse problems are obtained.
{"title":"A Class of Inverse Boundary Value Problems for (λ, 1) Bi-Analytic Functions","authors":"Juan Lin","doi":"10.1051/wujns/2023283185","DOIUrl":"https://doi.org/10.1051/wujns/2023283185","url":null,"abstract":"In this paper, a class of inverse boundary value problems for (λ, 1) bi-analytic functions is given. Using the method of Riemann boundary value problem for analytic functions, the conditions of solvability and the expression of the solutions for the inverse problems are obtained.","PeriodicalId":23976,"journal":{"name":"Wuhan University Journal of Natural Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44985794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1051/wujns/2023283217
Tian Wang, Youjiang Lin
In this paper, we demonstrate the existence of iterated Steiner symmetrizations of [see formula in PDF] that does not converge, even if the sequence of directions is dense in the unit sphere.
{"title":"The Non-Convergence of Steiner Symmetrizations","authors":"Tian Wang, Youjiang Lin","doi":"10.1051/wujns/2023283217","DOIUrl":"https://doi.org/10.1051/wujns/2023283217","url":null,"abstract":"In this paper, we demonstrate the existence of iterated Steiner symmetrizations of [see formula in PDF] that does not converge, even if the sequence of directions is dense in the unit sphere.","PeriodicalId":23976,"journal":{"name":"Wuhan University Journal of Natural Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43973703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-06-01DOI: 10.1051/wujns/2023283271
Hao-Wen Chen, Sanjun Liu, Guohong Lai
In the inverter circuit, there exists a specific on-off time in each power transistor. As such, to prevent a short circuit of the two switch devices on the upper and lower bridge arms, a specific dead time must be set in the pulse width modulation (PWM) and the sinusoidal pulse width modulation (SPWM) signals. In this paper, an intellectual property (IP) core that can introduce a high-precision dead time of arbitrary length into PWM or SPWM signals of the inverter is designed to increase the precision, convenience and generalization of dead time control, resulting in a boosted control accuracy of up to 10 ns. Moreover, the added Avalon bus enables IP cores to be accessed by the field programmable gate array (FPGA) processor in a standard manner and multiple IP cores of the same class can be easily incorporated. In addition, an application for setting and compensating for dead time in a three-phase inverter based on system on programmable chip (SOPC) technology is presented. With the Nios II CPU as its core, the system adopts the mean voltage compensation method to calculate the compensation voltage, and performs dead-time compensation in a feed-forward manner. The three dead-time IP cores are controlled by Avalon bus. These allow the dead time of three groups of power transistors to be accurately controlled and flexibly adjusted. The system also features the master computer communication function while boasting the advantages of flexible control, high precision and low cost.
在逆变电路中，每个功率晶体管都有一个特定的通断时间。因此，为了防止上下桥臂上的两个开关器件短路，必须在脉宽调制(PWM)和正弦脉宽调制(SPWM)信号中设置特定的死区时间。为了提高死区时间控制的精度、便利性和通用性，本文设计了一种可以在逆变器的PWM或SPWM信号中引入任意长度的高精度死区时间的知识产权(IP)内核，从而将控制精度提高到10ns。此外，增加的Avalon总线使IP核能够通过现场可编程门阵列(FPGA)处理器以标准方式访问，并且可以轻松合并多个同类IP核。此外，还介绍了基于可编程芯片系统(SOPC)技术在三相逆变器死区时间设定与补偿中的应用。系统以Nios II CPU为核心，采用平均电压补偿法计算补偿电压，并采用前馈方式进行死区补偿。三个死区IP核由Avalon总线控制。这使得三组功率晶体管的死区时间可以精确控制和灵活调整。该系统具有主控机通信功能，同时具有控制灵活、精度高、成本低等优点。
{"title":"High-Precision Dead-Time Intellectual Property Core and Its Compensation for Inverters","authors":"Hao-Wen Chen, Sanjun Liu, Guohong Lai","doi":"10.1051/wujns/2023283271","DOIUrl":"https://doi.org/10.1051/wujns/2023283271","url":null,"abstract":"In the inverter circuit, there exists a specific on-off time in each power transistor. As such, to prevent a short circuit of the two switch devices on the upper and lower bridge arms, a specific dead time must be set in the pulse width modulation (PWM) and the sinusoidal pulse width modulation (SPWM) signals. In this paper, an intellectual property (IP) core that can introduce a high-precision dead time of arbitrary length into PWM or SPWM signals of the inverter is designed to increase the precision, convenience and generalization of dead time control, resulting in a boosted control accuracy of up to 10 ns. Moreover, the added Avalon bus enables IP cores to be accessed by the field programmable gate array (FPGA) processor in a standard manner and multiple IP cores of the same class can be easily incorporated. In addition, an application for setting and compensating for dead time in a three-phase inverter based on system on programmable chip (SOPC) technology is presented. With the Nios II CPU as its core, the system adopts the mean voltage compensation method to calculate the compensation voltage, and performs dead-time compensation in a feed-forward manner. The three dead-time IP cores are controlled by Avalon bus. These allow the dead time of three groups of power transistors to be accurately controlled and flexibly adjusted. The system also features the master computer communication function while boasting the advantages of flexible control, high precision and low cost.","PeriodicalId":23976,"journal":{"name":"Wuhan University Journal of Natural Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46969487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.1051/wujns/2023282117
Yue Zhang, Zhenzhen Huang, Longmei Shi, Jian Zou
Affected by the Federal Reserve's interest rate hike and the downward pressure on the domestic economy, the phenomenon of default is still prominent. The credit risk of the listed companies has become a growing concern of the community. In this paper we present a novel credit risk measurement method based on a dimensional reduation technique. The method first extracts the risk measure indexes from the basal financial data via dimensional reduation by using deep belief network (DBN), exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) in turn. And then the credit risk is measured by a systemic structural equation model (SEM) and logistic distribution. To validate the proposed method, we employ the financial data of the listed companies from Q1 2019 to Q2 2022. The empirical results show its effectiveness on statistical evaluation, assessment on testing samples and credit risk forecasting.
{"title":"A Novel DBN-EFA-CFA-Based Dimensional Reduation for Credit Risk Measurement","authors":"Yue Zhang, Zhenzhen Huang, Longmei Shi, Jian Zou","doi":"10.1051/wujns/2023282117","DOIUrl":"https://doi.org/10.1051/wujns/2023282117","url":null,"abstract":"Affected by the Federal Reserve's interest rate hike and the downward pressure on the domestic economy, the phenomenon of default is still prominent. The credit risk of the listed companies has become a growing concern of the community. In this paper we present a novel credit risk measurement method based on a dimensional reduation technique. The method first extracts the risk measure indexes from the basal financial data via dimensional reduation by using deep belief network (DBN), exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) in turn. And then the credit risk is measured by a systemic structural equation model (SEM) and logistic distribution. To validate the proposed method, we employ the financial data of the listed companies from Q1 2019 to Q2 2022. The empirical results show its effectiveness on statistical evaluation, assessment on testing samples and credit risk forecasting.","PeriodicalId":23976,"journal":{"name":"Wuhan University Journal of Natural Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48568521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.1051/wujns/2023282106
Yi Zhang
The time-scale non-shifted Hamiltonian dynamics are investigated, including both general holonomic systems and nonholonomic systems. The time-scale non-shifted Hamilton principle is presented and extended to nonconservative system, and the dynamic equations in Hamiltonian framework are deduced. The Noether symmetry, including its definition and criteria, for time-scale non-shifted Hamiltonian dynamics is put forward, and Noether's theorems for both holonomic and nonholonomic systems are presented and proved. The non-shifted Noether conservation laws are given. The validity of the theorems is verified by two examples.
{"title":"A Study on Time Scale Non-Shifted Hamiltonian Dynamics and Noether's Theorems","authors":"Yi Zhang","doi":"10.1051/wujns/2023282106","DOIUrl":"https://doi.org/10.1051/wujns/2023282106","url":null,"abstract":"The time-scale non-shifted Hamiltonian dynamics are investigated, including both general holonomic systems and nonholonomic systems. The time-scale non-shifted Hamilton principle is presented and extended to nonconservative system, and the dynamic equations in Hamiltonian framework are deduced. The Noether symmetry, including its definition and criteria, for time-scale non-shifted Hamiltonian dynamics is put forward, and Noether's theorems for both holonomic and nonholonomic systems are presented and proved. The non-shifted Noether conservation laws are given. The validity of the theorems is verified by two examples.","PeriodicalId":23976,"journal":{"name":"Wuhan University Journal of Natural Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48299841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.1051/wujns/2023282099
Dengming Liu, Ao Chen
This paper is mainly focused on the global existence and extinction behaviour of the solutions to a doubly nonlinear parabolic equation with logarithmic nonlinearity. By making use of energy estimates method and a series of ordinary differential inequalities, the global existence of the solution is obtained. Moreover, we give the sufficient conditions on the occurrence (or absence) of the extinction behaviour.
{"title":"Global Existence and Extinction Behaviour for a Doubly Nonlinear Parabolic Equation with Logarithmic Nonlinearity","authors":"Dengming Liu, Ao Chen","doi":"10.1051/wujns/2023282099","DOIUrl":"https://doi.org/10.1051/wujns/2023282099","url":null,"abstract":"This paper is mainly focused on the global existence and extinction behaviour of the solutions to a doubly nonlinear parabolic equation with logarithmic nonlinearity. By making use of energy estimates method and a series of ordinary differential inequalities, the global existence of the solution is obtained. Moreover, we give the sufficient conditions on the occurrence (or absence) of the extinction behaviour.","PeriodicalId":23976,"journal":{"name":"Wuhan University Journal of Natural Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44198115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.1051/wujns/2023282163
Wang Zhou, Jun Tao, Xin Li
Currently, digital certificate systems based on blockchain have been extensively developed and adopted. However, most of them do not take into account the certificate quality. To evaluate the credibility of certificates issued by educational institutions, we propose a novel blockchain-based system with credit self-adjustment (BC-CS). In BC-CS, employers can provide feedback according to the performances of their employees (i.e., students) holding different certificates. Based on the feedback, BC-CS automatically adjusts the certificate credits by using our proposed credit self-adjustment algorithm. To verify the feasibility of our proposed system, a decentralized application prototype has been developed on an Ethereum network. Experimental results demonstrate that the proposed system can fully support multi-step accreditation and automatic adjustment for certificate credit.
{"title":"A Blockchain-Based Certificate System with Credit Self-Adjustment","authors":"Wang Zhou, Jun Tao, Xin Li","doi":"10.1051/wujns/2023282163","DOIUrl":"https://doi.org/10.1051/wujns/2023282163","url":null,"abstract":"Currently, digital certificate systems based on blockchain have been extensively developed and adopted. However, most of them do not take into account the certificate quality. To evaluate the credibility of certificates issued by educational institutions, we propose a novel blockchain-based system with credit self-adjustment (BC-CS). In BC-CS, employers can provide feedback according to the performances of their employees (i.e., students) holding different certificates. Based on the feedback, BC-CS automatically adjusts the certificate credits by using our proposed credit self-adjustment algorithm. To verify the feasibility of our proposed system, a decentralized application prototype has been developed on an Ethereum network. Experimental results demonstrate that the proposed system can fully support multi-step accreditation and automatic adjustment for certificate credit.","PeriodicalId":23976,"journal":{"name":"Wuhan University Journal of Natural Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45564543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
With the rapid development of intelligent traffic information monitoring technology, accurate identification of vehicles, pedestrians and other objects on the road has become particularly important. Therefore, in order to improve the recognition and classification accuracy of image objects in complex traffic scenes, this paper proposes a segmentation method of semantic redefine segmentation using image boundary region. First, we use the SegNet semantic segmentation model to obtain the rough classification features of the vehicle road object, then use the simple linear iterative clustering (SLIC) algorithm to obtain the over segmented area of the image, which can determine the classification of each pixel in each super pixel area, and then optimize the target segmentation of the boundary and small areas in the vehicle road image. Finally, the edge recovery ability of condition random field (CRF) is used to refine the image boundary. The experimental results show that compared with FCN-8s and SegNet, the pixel accuracy of the proposed algorithm in this paper improves by 2.33% and 0.57%, respectively. And compared with Unet, the algorithm in this paper performs better when dealing with multi-target segmentation.
{"title":"Complex Traffic Scene Image Classification Based on Sparse Optimization Boundary Semantics Deep Learning","authors":"Xiwei Zhou, Huifeng Wang, Saisai Li, Haonan Peng, Jianfeng Wu","doi":"10.1051/wujns/2023282150","DOIUrl":"https://doi.org/10.1051/wujns/2023282150","url":null,"abstract":"With the rapid development of intelligent traffic information monitoring technology, accurate identification of vehicles, pedestrians and other objects on the road has become particularly important. Therefore, in order to improve the recognition and classification accuracy of image objects in complex traffic scenes, this paper proposes a segmentation method of semantic redefine segmentation using image boundary region. First, we use the SegNet semantic segmentation model to obtain the rough classification features of the vehicle road object, then use the simple linear iterative clustering (SLIC) algorithm to obtain the over segmented area of the image, which can determine the classification of each pixel in each super pixel area, and then optimize the target segmentation of the boundary and small areas in the vehicle road image. Finally, the edge recovery ability of condition random field (CRF) is used to refine the image boundary. The experimental results show that compared with FCN-8s and SegNet, the pixel accuracy of the proposed algorithm in this paper improves by 2.33% and 0.57%, respectively. And compared with Unet, the algorithm in this paper performs better when dealing with multi-target segmentation.","PeriodicalId":23976,"journal":{"name":"Wuhan University Journal of Natural Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46500543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-01DOI: 10.1051/wujns/2023282093
Linzeng Tang, Wei Wang
In this paper, we establish a characterization of the polarity mapping for 1-dimensional convex bodies, which is a supplement to the result for such a characterization obtained by Böröczky and Schneider.
{"title":"A Characterization of the Polarity Mapping for Convex Bodies","authors":"Linzeng Tang, Wei Wang","doi":"10.1051/wujns/2023282093","DOIUrl":"https://doi.org/10.1051/wujns/2023282093","url":null,"abstract":"In this paper, we establish a characterization of the polarity mapping for 1-dimensional convex bodies, which is a supplement to the result for such a characterization obtained by Böröczky and Schneider.","PeriodicalId":23976,"journal":{"name":"Wuhan University Journal of Natural Sciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44822947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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