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Automated classification of software change messages by semi-supervised Latent Dirichlet Allocation

Information and Software Technology 2015年 57卷 369-377页

作者： Ying Fu Meng Yan Xiaohong Zhang Ling Xu Dan Yang Jeffrey D. Kymer School of Software Engineering Chongqing University Chongqing 401331 PR China Key Laboratory of Dependable Service Computing in Cyber Physical Society Ministry of Education Chongqing 400044 PR China

Context Topic models such as probabilistic Latent Semantic Analysis (pLSA) and Latent Dirichlet Allocation (LDA) have demonstrated success in mining software repository tasks. Understanding software change messages described by the unstructured nature-language text is one of the fundamental challenges in mining these messages in repositories. Objective We seek to present a novel automatic change message classification method characterized by semi-supervised topic semantic analysis. Method In this work, we present a semi-supervised LDA based approach to automatically classify change messages. We use domain knowledge of software changes to make labeled samples which are added to build the semi-supervised LDA model. Next, we verify the cross-project analysis application of our method on three open-source projects. Our method has two advantages over existing software change classification methods: First of all, it mitigates the issue of how to set the appropriate number of latent topics. We do not have to choose the number of latent topics in our method, because it corresponds to the number of class labels. Second, this approach utilizes the information provided by the label samples in the training set. Results Our method automatically classified about 85% of the change messages in our experiment and our validation survey showed that 70.56% of the time our automatic classification results were in agreement with developer opinions. Conclusion Our approach automatically classifies most of the change messages which record the cause of the software change and the method is applicable to cross-project analysis of software change messages.

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Optimizing data placement for reducing shift operations on Domain Wall Memories

Optimizing data placement for reducing shift operations on D...

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Design Automation Conference

作者： Xianzhang Chen Edwin H.-M. Sha Qingfeng Zhuge Penglin Dai Weiwen Jiang College of Computer Science Chongqing University Chongqing China Ministry of Education Key Laboratory of Dependable Service Computing in Cyber Physical Society Chongqing

Domain Wall Memory (DWM) using nanowire with data access port, exhibits extraordinary high density, low power leakage, and low access latency. These properties enable DWM to become an attractive candidate for replacing traditional memories. However, data accesses on DWM may require multiple shift operations before the port points to requested data, resulting in varying access latencies. Data placement, therefore, has a significant impact on the performance of data accesses on DWM. This paper studies compiler-based optimization techniques for data placement on DWM. To the authors' best knowledge, this is the first work addressing data placement problem on DWM. We present an efficient heuristic, called Grouping-Based Data Placement (GBDP), for the data placement problem of a given data access sequence on DWM. The experimental results show that GBDP has a significant performance improvement; for example, GBDP reduces 82% shift operations on an 8-port DWM compared with non-optimized approach.

关键词： Ports (Computers) Magnetic tunneling Magnetic domain walls Joining processes Data models Magnetic domains Optimization

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Designing an efficient persistent in-memory file system

Designing an efficient persistent in-memory file system

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IEEE Non-Volatile Memory Systems and Applications Symposium (NVMSA)

作者： Edwin H.-M. Sha Xianzhang Chen Qingfeng Zhuge Liang Shi Weiwen Jiang College of Computer Science Chongqing University Chongqing China Ministry of Education Key Laboratory of Dependable Service Computing in Cyber Physical Society Chongqing

As the emerging technologies of persistent memory, such as MRAM, PCM, etc., provide opportunities for connecting persistent memory to main memory bus directly, file system structure needs re-studying and re-designing. This paper presents a new design of persistent, in-memory file system for computers systems employing persistent memory. We introduce a novel design framework based on the concept that each file has its own “File Virtual Address Space”. Following this idea, address mapping of file data access can be efficiently handled by address translation hardware. The new design pushes the boundary of persistent, in-memory file system to such an extent that software layers in I/O stack are bypassed. File data can be read continuously without interrupt or traversing metadata structure. The proposed file system, called Sustainable In-Memory File System (SIMFS), is implemented in Linux. Extensive experiments have been conducted, showing that the throughput of SIMFS approaches the memory bus bandwidth in best cases. Comparing with other in-memory file systems, SIMFS reaches 50-80 times, 5 times, and 1.1-1.6 times faster than PRAMFS, EXT4 on Ramdisk, and PMFS, respectively. To the authors' knowledge, SIMFS gives the best known results in literature.

关键词： Throughput Metadata Random access memory Hardware Linux File systems

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On the Design of High-Performance and Energy-Efficient Probabilistic Self-Timed Systems

On the Design of High-Performance and Energy-Efficient Proba...

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IEEE International Conference on High Performance computing and Communications (HPCC)

作者： Edwin H.-M. Sha Weiwen Jiang Qingfeng Zhuge Lei Yang Xianzhang Chen College of Computer Science Chongqing University Chongqing China Key Laboratory of Dependable Service Computing in Cyber Physical Society Ministry of Education Chongqing China

Traditional synchronous systems relied on a global clock to maintain synchronization have incurred problems in worst-case performance and power consumption. A self-timed system that does not depend on a global clock is one of the high-caliber candidates to solve such problems. In this paper, a probabilistic self-timed system model is studied, on which task execution time is represented by a random variable. This paper presents the fundamental properties on time behavior of the probabilistic self-timed system and establishes formulas to calculate its throughput. Then, using the results, efficient algorithms are designed to optimize system throughput and minimize energy consumption. Experimental results show that the throughput of self-timed systems optimized by our algorithms achieves 33.73% improvement compared with that of the optimized synchronous systems. Additionally, the proposed algorithms on minimizing energy can make a good performance-energy tradeoff, achieving 64.36% improvement on energy consumption with little reduction on performance.

关键词： Probabilistic logic Energy consumption Throughput Clocks Algorithm design and analysis System performance Synchronization

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A generic feedback system for better evaluation of teacher performance

A generic feedback system for better evaluation of teacher p...

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IEEE International Conference on Software Engineering and service Sciences (ICSESS)

作者： Hamad Naeem Jun Sang Waqar Ali Abro Muhammad Rashid Naeem School of Software Engineering Chongqing University Chongqing China Key Laboratory of Dependable Service Computing in Cyber Physical Society Ministry of Education Chongqing China

In existing educational environment, teacher's performance is playing vital role in growth of students as well as institution. The quality of Instruction is basic constituent for successful learning. For better collaboration between students and teachers, it has become mandatory to introduce comprehensive performance evaluation mechanism. In modern age, information technology provides us optimal solution to evaluate teacher's performance. In this paper, we proposed a generic feedback model using unified modeling language (UML). This model can be easily implemented in any institutional environment due to its non specific behavior. This model predicts better results of teacher's performance using methods of data mining tool. In the conclusion, we compared results of various data mining techniques and also suggesting an appropriate method for this system.

关键词： Decision trees service computing Software engineering Computational modeling Data models Performance evaluation

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Global climate

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Bulletin of the American Meteorological Society 2020年第8期101卷 S9-S128页

作者： Dunn, R.J.H. Stanitski, D.M. Gobron, N. Willett, K.M. European Centre for Medium-Range Weather Forecasts Reading United Kingdom University of Maryland College Park Maryland Met Office Hadley Centre Exeter United Kingdom University of Reading Reading United Kingdom Department of Atmospheric and Planetary Science Hampton University Hampton Virginia NOAA/NESDIS National Centers for Environmental Information Asheville North Carolina University of Bremen Bremen Germany NOAA/OAR Earth System Research Laboratories Boulder Colorado Centro de Investigaciones sobre Desertificación – Spanish National Research Council Moncada (Valencia) Spain and Regional Climate Group Department of Earth Sciences University of Gothenburg Gothenburg Sweden Instituto de Geografía Pontificia Universidad Católica de Valparaíso Valparaíso Chile NOAA/OAR ESRL Global Monitoring Laboratory Boulder Colorado Department of Civil and Environmental Engineering Princeton University Princeton New Jersey Global Precipitation Climatology Centre Deutscher Wetterdienst Offenbach Germany National Oceanography Centre Southampton United Kingdom School of Engineering Newcastle University Newcastle-upon-Tyne United Kingdom Université de Paris Institut de physique du globe de Paris CNRS IGN Paris France and ENSG-Géomatique IGN Marne-la-Vallée France Global Modeling and Assimilation Office NASA Goddard Space Flight Center Greenbelt Maryland Sorbonne Université Paris France Universität Hamburg Hamburg Germany Department of Meteorology University of Reading Reading United Kingdom Geology Department University Centre in Svalbard Longyearbyen Norway Jet Propulsion Laboratory California Institute of Technology Wrightwood California The University of Alabama in Huntsville Huntsville Alabama IBS Center for Climate Physics Busan South Korea German Aerospace Center (DLR) Oberpfaffenhofen Wessling Germany Cooperative Institute for Research in Environmental Sciences University of Colorado Boulder and Physical Sciences Division NOAA/Earth System Research Labo

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Movie Box Office Prediction Using Microblog Based on Emotional Intensity and Publicity

Movie Box Office Prediction Using Microblog Based on Emotion...

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2015 International Conference on Advances in Management Engineering and Information Technology(AMEIT 2015)

作者： S.B.Zhou J.Luo W.Wang J.L.Zhang Key Laboratory of Dependable Service Computing in Cyber Physical Society Ministry of Education Chongqing University Hua Ying (Beijing) Film and Television Investment Management Ltd

As the drastic improvement of social media, there are lots of research areas derived from them that need to be explored. The most important of them is the predictability of social media users' behavior to events occurred in real world. This paper explores the feasibility and accuracy of predictive power through social media that is exemplified by movie box office prediction, using microblog data. As compared to previous work, the modeling method based on emotional intensity has been proposed in this paper. The intensity of emotion expressed on microblogs is weighted and the features of amount and semantics are fused. Meanwhile, the advance publicity of movies is taken as the feature which can influence the box office. Linear, SVM and BP neural network model are applied to validate the performance of prediction methods. Experimental results show that our emotional intensity based input model has a high correlation with box office and real data. With the results, the predictive power of microblogs to social events in real world can be further demonstrated. The results also demonstrate the predictive power of microblogs to social events in real world.

关键词： microblog prediction box office emotional intensity publicity

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Model Reference Adaptive Controller to Regulate Sample Temperature in Microwave Heating Application

Model Reference Adaptive Controller to Regulate Sample Tempe...

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第三十四届中国控制会议

作者： Yuzhe Zhang Shan Liang Yupeng Yuan Qingyu Xiong College of Automation Chongqing University Key Laboratory of Dependable Service Computing in Cyber Physical Society Ministry of Education Chongqing University College of Software Engineering Chongqing University

ISBN: (纸本)9781467374439

Microwave(MW) energy is a promising energy in industrial heating process as a novel, clean and efficient energy source. However, physical parameter and dielectric property in the process are time-varying and the relationship between input MW power and output temperature of microwave heating process is nonlinear. Consequently, it is difficult to design a good temperature controller and simultaneously sustain the desired transient performance. Due to the problems existing in previous bang-bang temperature control method systems, such as chattering phenomenon and low robustness, this paper presents the temperature control method for MW heating system by using Model Reference Adaptive Control(MRAC) to adjust the MW power. The direct MRAC with unnormalized adaptive law is tested and analyzed to the MW heating model. The simulation result shows that, with proper selection of adaptation gain and reference model, MRAC method has capabilities to provide anticipant temperature regulating performance.

关键词： Microwave(MW) heating,Model Reference Adaptive Control(MRAC),Temperature control,Reference model

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Discrete-time Model Predictive Temperature Control Based on Laguerre Function for a Microwave Heating Application

Discrete-time Model Predictive Temperature Control Based on ...

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第27届中国控制与决策会议

作者： Xueli Hu Shan Liang Yupeng Yuan Qingyu Xiong College of Automation Chongqing University Key Laboratory of Dependable Service Computing in Cyber Physical Society Ministry of Education Chongqing University College of Software Engineering Chongqing University

ISBN: (纸本)9781479970186

Precise control of the material's time-temperature profile is essential for preventing thermal runaway in microwave heating *** paper presents results on tracking expected temperature of samples using a discretetime model predictive control(DMPC) based on Laguerre *** of the temperature controller is presented,and simulation results from three cases:without any constraint and disturbance,with linear constraints and with linear constraints combined with disturbance verify the designed controller is effective.

关键词： Temperature tracking,DMPC,Laguerre function

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Which Non-functional Requirements Do Developers Focus On? An Empirical Study on Stack Overflow Using Topic Analysis

Which Non-functional Requirements Do Developers Focus On? An...

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International Mining Software Repositories, MSR

作者： Jie Zou Ling Xu Weikang Guo Meng Yan Dan Yang Xiaohong Zhang The School of Software Engineering Chongqing University Chongqing PR China Key Laboratory of Dependable Service Computing in Cyber Physical Society Ministry of Education Chongqing PR China

Programming question and answer (Q&A) websites, such as Stack Overflow, gathered knowledge and expertise of developers from all over the world, this knowledge reflects some insight into the development activities. To comprehend the actual thoughts and needs of the developers, we analyzed the non-functional requirements (NFRs) on Stack Overflow. In this paper, we acquired the textual content of Stack Overflow discussions, utilized the topic model, latent Dirichlet allocation (LDA), to discover the main topics of Stack Overflow discussions, and we used the wordlists to find the relationship between the discussions and NFRs. We focus on the hot and unresolved NFRs, the evolutions and trends of the NFRs in their discussions. We found that the most frequent topics the developers discuss are about usability and reliability while they concern few about maintainability and efficiency. The most unresolved problems also occurred in usability and reliability. Moreover, from the visualization of the NFR evolutions over time, we can find the trend for each NFR.

关键词： Usability Reliability Market research Data mining Manuals Resource management

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