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A kinetic study and factor analysis of solar thermochemical membrane reactors for syngas production

Science China Technological Sciences 2025年第1期 207-221页

作者： Jiaxin xinG Chao XU xiangyu SUN xin xia Fei JIN Qiongqiong JIANG Jiale GAO Key Laboratory of Power Station Energy Transfer Conversion and System of MOE School of Energy Power and Mechanical EngineeringNorth China Electric Power University Department of Chemistry University College London School of Chemistry and Chemical Engineering Ningxia Key Laboratory of Solar Chemical Conversion TechnologyState Ethnic Affairs CommissionNorth Minzu University

Solar thermochemical conversion technologies are promising for effectively utilizing solar energy by capturing the full spectrum of solar radiation. To overcome the challenges of low energy conversion efficiency and intermittency faced by solar thermochemical conversion, these technologies can be effectively integrated with membrane reactor technology. Although the performance of solar thermochemical membrane reactors has been experimentally tested, the chemical reactions and oxygen transport mechanisms during the energy conversion process remain poorly understood. This study introduces a resistance network model to elucidate the interactions between interfacial reactions and bulk diffusion during simultaneous oxidationreduction reactions on both sides of the membrane. We analyzed the oxygen flux of the membrane reactor under various operating conditions using this model to identify the reaction/transport-limiting side of the overall process. The most effective solar membrane reactor configuration utilizes natural gas and CO2, facilitating clean conversion of fossil fuels with significant advantages in fuel production and energy efficiency. Introducing CH4lowers the overall reaction temperature, maintains low oxygen partial pressure on the sweep side, and produces a synthesis gas with a 2:1 H2/CO molar ratio. Finally, a sensitivity analysis was used to explore the relationship between overall fuel production performance and operational parameters,highlighting the critical role of this research in enhancing the reaction and transport performance of membrane reactors and advancing the development of solar-driven thermochemical fuel production technologies.

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A manual inspection of Defects4J bugs and its implications for automatic program repair

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Science China(Information Sciences) 2019年第10期62卷 31-46页

作者： Jiajun JIANG Yingfei XIONG xin xia Key Laboratory of High Confidence Software Technologies Ministry of EducationInstitute of Software Department of Computer Science and Technology Peking University The Faculty of Information Technology Monash University

Automatic program repair techniques, which target to generate correct patches for real-world defects automatically, have gained a lot of attention in the last decade. Many different techniques and tools have been proposed and developed. However, even the most sophisticated automatic program repair techniques can only repair a small portion of defects while producing a large number of incorrect patches.A possible reason for the low performance is the test suites of real-world programs are usually too weak to guarantee the behavior of a program. To understand to what extent defects can be fixed with exiting test suites, we manually analyzed 50 real-world defects from Defects4J, where a large portion(i.e., 82%) of them were correctly fixed. This result suggests that there is much room for the current automatic program repair techniques to improve. Furthermore, we summarized seven fault localization and seven patch generation strategies that are useful in localizing and fixing these defects, and compared those strategies with current techniques. The results indicate potential directions to improve automatic program repair in the future.

关键词： automatic defect repair fault localization manual repair software maintenance case study

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Combined classifier for cross-project defect prediction： an extended empirical study

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Frontiers of Computer Science 2018年第2期12卷 280-296页

作者： Yun ZHANG David LO xin xia Jianling SUN College of Computer Science and Technology Zhejiang University Hangzhou 310027 China School of Information Systems Singapore Management University Singapore 641674 Singapore

To facilitate developers in effective allocation of their testing and debugging efforts, many software defect prediction techniques have been proposed in the literature. These techniques can be used to predict classes that are more likely to be buggy based on the past history of classes, methods, or certain other code elements. These techniques are effective provided that a sufficient amount of data is available to train a prediction model. However, sufficient training data are rarely available for new software projects. To resolve this problem, cross-project defect prediction, which transfers a prediction model trained using data from one project to another, was proposed and is regarded as a new challenge in the area of defect prediction. Thus far, only a few cross-project defect prediction techniques have been proposed. To advance the state of the art, in this study, we investigated seven composite algorithms that integrate multiple machine learning classifiers to improve cross-project defect prediction. To evaluate the performance of the composite algorithms, we performed experiments on 10 open-source software systems from the PROMISE repository, which contain a total of 5,305 instances labeled as defective or clean. We compared the composite algorithms with the combined defect predictor where logistic regression is used as the meta classification algorithm （CODEPLogistic）, which is the most recent cross-project defect prediction algorithm in terms of two standard evaluation metrics： cost effectiveness and F-measure. Our experimental results show that several algorithms outperform CODEPLogistic：Maximum voting shows the best performance in terms of F-measure and its average F-measure is superior to that of CODEPLogistic by 36.88%. Bootstrap aggregation （Bagging J48） shows the best performance in terms of cost effectiveness and its average cost effectiveness is superior to that of CODEPLogistic by 15.34%.

关键词： defect prediction cross-project classifier combination

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High-Impact Bug Report Identification with Imbalanced Learning Strategies

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Journal of Computer Science & Technology 2017年第1期32卷 181-198页

作者： xin-Li Yang David Lo xin xia Qiao Huang Jian-Ling Sun College of Computer Science and Technology Zhejiang University Hangzhou 310027 China School of Information Systems Singapore Management University Singapore Singapore

In practice, some bugs have more impact than others and thus deserve more immediate attention. Due to tight schedule and limited human resources, developers may not have enough time to inspect all bugs. Thus, they often concentrate on bugs that are highly impactful. In the literature, high-impact bugs are used to refer to the bugs which appear at unexpected time or locations and bring more unexpected effects （i.e., surprise bugs）, or break pre-existing functionalities and destroy the user experience （i.e., breakage bugs）. Unfortunately, identifying high-impact bugs from thousands of bug reports in a bug tracking system is not an easy feat. Thus, an automated technique that can identify high-impact bug reports can help developers to be aware of them early, rectify them quickly, and minimize the damages they cause. Considering that only a small proportion of bugs are high-impact bugs, the identification of high-impact bug reports is a difficult task. In this paper, we propose an approach to identify high-impact bug reports by leveraging imbalanced learning strategies. We investigate the effectiveness of various variants, each of which combines one particular imbalanced learning strategy and one particular classification algorithm. In particular, we choose four widely used strategies for dealing with imbalanced data and four state-of-the-art text classification algorithms to conduct experiments on four datasets from four different open source projects. We mainly perform an analytical study on two types of high-impact bugs, i.e., surprise bugs and breakage bugs. The results show that different variants have different performances, and the best performing variants SMOTE （synthetic minority over-sampling technique）＋ KNN （K-nearest neighbours） for surprise bug identification and RUS （random under-sampling）＋ NB （naive Bayes） for breakage bug identification outperform the Fl-scores of the two state-of-the-art approaches by Thung et al. and Garcia and Shihab.

关键词： high-impact bug imbalanced learning bug report identification

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Automated Android application permission recommendation

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Science China(Information Sciences) 2017年第9期60卷 132-148页

作者： Lingfeng BAO David LO xin xia Shanping LI College of Computer Science and Technology Zhejiang University School of Information Systems Singapore Management University Department of Computer Science University of British Columbia

The number of Android applications has increased rapidly as Android is becoming the dominant platform in the smartphone market. Security and privacy are key factors for an Android application to be successful. Android provides a permission mechanism to ensure security and privacy. This permission mechanism requires that developers declare the sensitive resources required by their applications. On installation or during runtime, users are required to agree with the permission request. However, in practice, there are numerous popular permission misuses, despite Android introducing official documents stating how to use these permissions properly. Some data mining techniques(e.g., association rule mining) have been proposed to help better recommend permissions required by an API. In this paper, based on popular techniques used to build recommendation systems, we propose two novel approaches to improve the effectiveness of the prior work. The first approach utilizes a collaborative filtering technique, which is inspired by the intuition that apps that have similar features — inferred from their APIs — usually share similar permissions. The second approach recommends permissions based on a text mining technique that uses a naive Bayes multinomial classification algorithm to build a prediction model by analyzing descriptions of apps. To evaluate these two approaches, we use 936 Android apps from F-Droid, which is a repository of free and open source Android applications. We find that our proposed approaches yield a significant improvement in terms of precision, recall, F1-score, and MAP of the top-k results over the baseline approach.

关键词： Android permission recommendation association rule collaborative filtering text mining

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Configuration Synthesis and Grasping Performance Analysis of Multi-Loop Coupling Capture Mechanism for Launch and Recovery of Torpedo-Shaped Autonomous Underwater Vehicle

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China Ocean Engineering 2024年第3期38卷 453-466页

作者： ZHANG Guo-xing xia xin-lu GUO Jin-wei School of Mechanical Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China

Research of capture mechanisms with strong capture adaptability and stable grasp is important to solve the problem of launch and recovery of torpedo-shaped autonomous underwater vehicles(AUVs).A multi-loop coupling capture mechanism with strong adaptability and high retraction rate has been proposed for the launch and recovery of torpedo-shaped AUVs with different morphological ***,the principle of capturing motion retraction is described based on the appearance characteristics of torpedo-shaped AUVs,and the configuration synthesis of the capture mechanism is carried out using the method of constrained chain ***,the screw theory is employed to analyze the degree of freedom(DoF)of the capture ***,the 3D model of the capture mechanism is established,and the kinematics and dynamics simulations are carried *** with the capture orientation requirements of the capture mechanism,the statics and vibration characteristics analyses are carried ***,considering the capture process and the underwater working environment,the motion characteristics and hydraulics characteristics of the capture mechanism are ***,a principle prototype is developed and the torpedo-shaped AUVs capture experiment is *** work provides technical reserves for the research and development of AUV capture special equipment.

关键词： capture mechanism torpedo-shaped AUVs configuration synthesis launch and recovery grasping performance analysis

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Temperature-Dependent Thermal Conductivity and Absorption Coefficient Identification of Quartz Window up to 1100 K

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Journal of Thermal Science 2023年第1期32卷 44-58页

作者： SHI Yu CHEN Xue SUN Chuang xia xin-Lin School of Energy Science and Engineering Harbin Institute of Technology(HIT)Harbin 150001China

The temperature-dependent absorption coefficient and thermal conductivity of a quartz window are obtained through experimental tests at a wide range of temperatures.A Fourier transform infrared spectrometer with a heated cavity is used for performing the transmittance *** spectral absorption coefficient of the quartz window is inverted by the transmittance information at different temperatures using a genetic ***,a quartz window-graphite plate-quartz window multilayer structure is designed,and the transient response of the structure subjected to high-temperature heating is recorded by a self-designed *** with the above absorption coefficient,a non-gray radiative-conductive heat transfer model is built for the multilayer structure,and the intrinsic thermal conductivity of the quartz window is ***,the effects of the temperature-dependent absorption coefficient and spectral selective features of the medium on the heat transfer characteristics are *** results show that the absorption coefficient gradually increases with *** intrinsic thermal conductivity of the quartz window varies from 1.35 to 2.52 W/(m·K)as the temperature rises,while the effective thermal conductivity is higher than the intrinsic thermal conductivity due to thermal radiation,specifically 26.4%higher at 1100 *** addition,it is found that the influence of the temperature-dependent absorption coefficient on temperature of unheated side shows a trend of first increasing and then *** the absorption coefficient varies greatly with wavelength,a non-gray radiative-conductive heat transfer model should be built for the semitransparent materials.

关键词： semitransparent material quartz window non-gray body absorption coefficient thermal conductivity

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Viability Loss Pattern under Rapid Dehydration of Antiaris toxicaria Axes and its Relation to Oxidative Damage

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Journal of Integrative Plant Biology 2010年第5期52卷 434-441页

作者： xia xin xin-Ming Jing Yong Liu Song-Quan Song Institute of Botany the Chinese Academy of Sciences Beijing 100093 China Graduate Schoolof the Chinese Academy of Sciences Beijing 100049 China Xishuangbanna Tropical Botanical Garden the Chinese Academy of Sciences Yunnan 666303 China

The relation between oxidative damage and viability loss of excised embryonic axes of Antiaris toxicaria subjected to rapid drying with silica gel at 15℃ was studied. Changes of survival rate, accumulation of thiobarbituric acid-reactive substances （TBARs）, activities of superoxide dismutase （SOD）, catalase （CAT）, ascorbate peroxidase （APX）, glutathione reductase （GR） and the permeability of cell membrane that was determined as relative electrolyte leakage （REL） were measured. The half-life moisture content （MC,50） was 0.41 g H=O/g DW （dry weight basis）. During drying, the activities of SOD, CAT and APX increased until MCL50, and declined thereafter. The generation speed of ·O2-, and content of H2O2 and TBARs remained steadily or even decreased at MC levels higher than MC,s0, demonstrating a low oxidative level in these axes. There was no significant correlation between viability loss and accumulation of reactive oxygen species or lipid peroxidation within the dehydration process until MCLs0. Whereas the increase in REL from the beginning of the drying process indicated that the cell membrane was damaged. In conclusion, under rapid drying with silica gel the viability loss of excised recalcitrant A. toxicaria axes seemed to be triggered by mechanical or physical damage, rather than metabolic damage.

关键词： ANTIARIS CELL membranes GLUTATHIONE SILICA

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What Security Questions Do Developers Ask？ A Large-Scale Study of Stack Overflow Posts

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Journal of Computer Science & Technology 2016年第5期31卷 910-924页

作者： xin-Li Yang David Lo xin xia Zhi-Yuan Wan Jian-Ling Sun College of Computer Science and Technology Zhejiang University Hangzhou 310027 China School of Information Systems Singapore Management University Singapore Singapore

Security has always been a popular and critical topic. With the rapid development of information technology, it is always attracting people＇s attention. However, since security has a long history, it covers a wide range of topics which change a lot, from classic cryptography to recently popular mobile security. There is a need to investigate security-related topics and trends, which can be a guide for security researchers, security educators and security practitioners. To address the above-mentioned need, in this paper, we conduct a large-scale study on security-related questions on Stack Overflow. Stack Overflow is a popular on-line question and answer site for software developers to communicate, collaborate, and share information with one another. There are many different topics among the numerous questions posted on Stack Overflow and security-related questions occupy a large proportion and have an important and significant position. We first use two heuristics to extract from the dataset the questions that are related to security based on the tags of the posts. And then we use an advanced topic model, Latent Diriehlet Allocation （LDA） tuned using Genetic Algorithm （GA）, to cluster different security-related questions based on their texts. After obtaining the different topics of security-related questions, we use their metadata to make various analyses. We summarize all the topics into five main categories, and investigate the popularity and difficulty of different topics as well. Based on the results of our study, we conclude several implications for researchers, educators and practitioners.

关键词： security Stack Overflow empirical study topic model

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Deep learning-based open API recommendation for Mashup development

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Science China(Information Sciences) 2023年第7期66卷 94-111页

作者： Ye WANG Junwu CHEN Qiao HUANG xin xia Bo JIANG School of Computer and Information Engineering Zhejiang Gongshang University Software Engineering Application Technology Lab

Mashup developers often need to find open application programming interfaces(APIs) for their composition application development. Although most enterprises and service organizations have encapsulated their businesses or resources online as open APIs, finding the right high-quality open APIs is not an easy task from a library with several open APIs. To solve this problem, this paper proposes a deep learning-based open API recommendation(DLOAR) approach. First, the hierarchical density-based spatial clustering of applications with a noise topic model is constructed to build topic models for Mashup clusters. Second,developers’ requirement keywords are extracted by the Text Rank algorithm, and the language model is built. Third, a neural network-based three-level similarity calculation is performed to find the most relevant open APIs. Finally, we complement the relevant information of open APIs in the recommended list to help developers make better choices. We evaluate the DLOAR approach on a real dataset and compare it with commonly used open API recommendation approaches: term frequency-inverse document frequency, latent dirichlet allocation, Word2Vec, and Sentence-BERT. The results show that the DLOAR approach has better performance than the other approaches in terms of precision, recall, F1-measure, mean average precision,and mean reciprocal rank.

关键词： Mashup development open API recommendation deep learning neural network service discovery

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