检索结果-南通市图书馆

unit Test Data Generation for C Using Rule-Directed Symbolic Execution

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2019年第3期34卷 670-689页

作者： Ming-Zhe Zhang Yun-Zhan Gong Ya-Wen Wang Da-Hai Jin State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876China

unit testing is widely used in software development. One important activity in unit testing is automatic test data generation. Constraint-based test data generation is a technique for automatic generation of test data, which uses symbolic execution to generate constraints. unit testing only tests functions instead of the whole program, where individual functions typically have preconditions imposed on their inputs. Conventional symbolic execution cannot detect these preconditions, let alone converting these preconditions into constraints. To overcome these limitations, we propose a novel unit test data generation approach using rule-directed symbolic execution for dealing with functions with missing input preconditions. Rule-directed symbolic execution uses predefined rules to detect preconditions in the individual function, and generates constraints for inputs based on preconditions. We introduce implicit constraints to represent preconditions, and unify implicit constraints and program constraints into integrated constraints. Test data generated based on integrated constraints can explore previously unreachable code and help developers find more functional faults and logical faults. We have implemented our approach in a tool called CTS-IC, and applied it to real-world projects. The experimental results show that rule-directed symbolic execution can find preconditions (implicit constraints) automatically from an individual function. Moreover, the unit test data generated by our approach achieves higher coverage than similar tools and efficiently mitigates missing input preconditions problems in unit testing for individual functions.

关键词： automated unit testing program constraint symbolic execution static analysis

EDOA: an efficient delay optimization approach for mixed-polarity Reed-Muller logic circuits under the unit delay model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2019年第5期13卷 1102-1115页

作者： Zhenxue HE Limin XIAO Fei GU Li RUAN Zhisheng HUO Mingzhe LI Mingfa ZHU Longbing ZHANG Rui LIU Xiang WANG College of Information Science and Technology Hebei Agricultural University Baoding 071001 China State Key Laboratory of Software Development Environment Beihang University Beijing 100083 China School of Computer Science and Engineering Beihang University Beijing 100083 China School of Electronic and Information Engineering Beihang University Beijing 100083 China State Key Laboratory of Computer Architecture Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China National Engineering Research Center for Science & Technology Resources Sharing Service Beijing 100083 China

Delay optimization has recently attracted signif-icant attention. However, few studies have focused on the delay optimization of mixed-polarity Reed-Muller (MPRM) logic circuits. In this paper, we propose an efficient delay op-timization approach (EDOA) for MPRM logic circuits under the unit delay model, which can derive an optimal MPRM logic circuit with minimum delay. First, the simplest MPRM expression with the fewest number of product terms is ob-tained using a novel Reed-Muller expression simplification approach (RMESA) considering don't-care terms. Second, a minimum delay decomposition approach based on a Huffman tree construction algorithm is utilized on the simplest MPRM expression. Experimental results on MCNC benchmark cir-cuits demonstrate that compared to the Berkeley SIS 1.2 and ABC, the EDOA can significantly reduce delay for most cir-cuits. Furthermore, for a few circuits, while reducing delay, the EDOA incurs an area penalty.

关键词： delay optimization mixed-polarity Reed-Muller logic circuits unit delay model don't-care terms,

A new building block with intramolecular D-A character for conjugated polymers: ladder structure based on B←N unit

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2019年第10期62卷 1387-1392页

作者： Xingxin Shao Chuandong Dou Jun Liu Lixiang Wang State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China University of Science and Technology of China School of Applied Chemistry and EngineeringHefei 230026China

The general strategy to construct D-A type conjugated polymers is alternating copolymerization of electron-donating(D)monomer and electron-accepting(A)*** this article,we report a new strategy to develop D-A type conjugated polymers,*** fuse the D and A units into a polycyclic structure to produce a building block and then polymerize the building block with another *** develop a new building block with ladder structure based on B←N unit,B←N bridged dipyridylbenzene(BNDPB).In the skeleton of BNDPB,one diamine-substituted phenylene ring(D unit)and two B←N-linked pyridyl rings(A unit)are fused together to produce the polycyclic *** to the presence of intramolecular D-A character,the building block itself exhibits narrow bandgap of 1.74 *** conjugated polymers based on BNDPB show unique electronic structures,*** HOMOs and delocalized LUMOs,which are rarely observed for conventional D-A conjugated *** polymers exhibit smaller bandgap than that of the building block BNDPB and display near-infrared(NIR)light absorption(λabs=ca.700 nm).This study thus provides not only a new strategy to design D-A conjugated polymers but also a new kind of building block with narrow bandgap.

关键词： D-A character conjugated polymers building block ladder structure B-N unit

Improving EGT sensing data anomaly detection of aircraft auxiliary power unit

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2020年第2期33卷 448-455页

作者： Liansheng LIU Yu PENG Lulu WANG Yu DONG Datong LIU Qing GUO School of Electronics and Information Engineering Harbin Institute of TechnologyHarbin 150080China China Southern Airlines Company Limited Shenyang Maintenance Base Shenyang 110169China China Southern Airlines Engineering Technology Research Center Shenyang 110169China

The reliability of the on-wing aircraft Auxiliary Power unit(APU)decides the cost and the comfort of flight to a large *** most important function of APU is to help start main engines by providing compressed *** on the condition of sudden shutdown in the air,APU can offer additional thrust for ***,its condition monitoring has drawn much attention from the academic and industrial *** the on-wing sensing data which can reflect its condition,Exhaust Gas Temperature(EGT)is one of the most important *** ensure the reliability of EGT,one kind of data-driven anomaly detection framework for EGT sensing data is proposed based on the Gaussian Process Regression and Kernel Principal Component *** situations of one-dimensional and two-dimensional input data for EGT anomaly detection are considered,*** cross-validation experiments are carried out by utilizing the real condition data of APU,which are provided by China Southern Airlines Company Limited Shenyang Maintenance *** anomalous stuck condition of EGT sensing data is also *** results show that the proposed EGT sensing data anomaly detection method can achieve better performance of false positive ratio,false negative ratio and accuracy.

关键词： Anomaly detection Auxiliary power unit Condition-based maintenance Data-driven framework Exhaust gas temperature

Predication of Plastic Flow Characteristics in Ferrite/Pearlite Steel Using a Fern unit Cell Method

在线全文

学校读者我要写书评

暂无评论

上海交通大学学报 2004年第Z2期38卷 61-66页

作者： Hong Li Jingtao Han Jing Liu Lv Zhang School of Material Sci. & Eng. Univ. Of Sci. &Tech. Beijing Beijing100083 China School of Material Sci. & Eng. Univ. Of Sci. &Tech. Beijing Beijing100083 China School of Material Sci. & Eng. Univ. Of Sci. &Tech. Beijing Beijing100083 China School of Material Sci. & Eng. Univ. Of Sci. &Tech. Beijing Beijing100083 China

The flow stress of ferrite/pearlite steel under uni-axial tension was simulated with finite element method (FEM) by applying commercial software MARC/MENTAT. Flow stress curves of ferrite/pearlite steels were calculated based on unit cell model. The effects of volume fraction, distribution and the aspect ratio of pearlite on tensile properties have been investigated.

关键词： ferrite/pearlite steel unit cell flow curve finite element method simulation

Diagonal-symmetrical and Midline-symmetrical unit Cells with Same Porosity for Bone Implant: Mechanical Properties Evaluation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2019年第3期16卷 468-479页

作者： Jian Li Diansheng Chen Yingying Zhang Yan Yao Zhongjun Mo Lizhen Wang Yubo Fan Robotic Institute Beihang University Beijing 100191 China Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age and Disability and Key Laboratory of Rehabilitation Aids Technology and System of the Ministry of Civil Affairs National Research Center for Rehabilitation Technical Aids Beijing 100176 China Beijing Advanced Innovation Center for Biomedical Engineering Beihang University Beijing 100191 China Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education School of Biological Science and Medical Engineering Beihang University Beijing 100191 China

In this study, mechanical properties of bionic porous structures with diagonal-symmetrical and midline-symmetrical unit cells were studied when the porosities were same. Three typical unit cells (Diamond (DO), Rhombic Dodecahedron (RD), and Octet Truss (OT)) were selected, in which DO has diagonal-symmetrical shape, while RD and OT share midline-symmetrical structure. Based on the same porosity, corresponding models were designed, and Ti6Al4V samples were manufactured by electron beam melting. Then, using Mechanical Properties Testing (MPT) and Finite Element Analysis (FEA) methodologies, mechanical properties and transmissions of different porous structures were evaluated. Besides, composition and details before and after printing were analyzed with Energy Dispersive Spectrometer (EDS), X-ray diffraction (XRD) and Scanning Electron Microscope (SEM). MPT results showed that midline-symmetrical shape would have superior compressive performance than diagonal-symmetrical shape, but opposite trend for the torsion performance, which were in line with FEA prediction. Furthermore, effective modulus of DO, RD and OT were 2.59 GPa, 4.89 GPa, and 1.77 GPa, approximating the mechanical properties of human bones. Additionally, manufacturing defects and discrepancies between FEA and MPT were found. This study would provide great helps for unit cell selection and initial mechanical properties matching for optimum bone implants.

关键词： bionic design porous implant mechanical properties unit cell additive manufacturing 3D printing

DETERMINING THICKENER UNDERFLOW CONCENTRATION AND unit AREA

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 1996年第3期6卷 29-35页

作者： Kang Yong Hu Xiaomin Deng Changlie Luo Qian(Department of Mineral Engineering, Northeastern University, Shenyong 110006) Department of Mineral Engineering Northeastern University Shenyang 110006 China

ＤＥＴＥＲＭＩＮＩＮＧＴＨＩＣＫＥＮＥＲＵＮＤＥＲＦＬＯＷＣＯＮＣＥＮＴＲＡＴＩＯＮＡＮＤＵＮＩＴＡＲＥＡ￥ＫａｎｇＹｏｎｇ；ＨｕＸｉａｏｍｉｎ；ＤｅｎｇＣｈａｎｇｌｉｅ；ＬｕｏＱｉａｎ（ＤｅｐａｒｔｍｅｎｔｏｆＭｉ... 详细信息

ＤＥＴＥＲＭＩＮＩＮＧＴＨＩＣＫＥＮＥＲＵＮＤＥＲＦＬＯＷＣＯＮＣＥＮＴＲＡＴＩＯＮＡＮＤＵＮＩＴＡＲＥＡ￥ＫａｎｇＹｏｎｇ；ＨｕＸｉａｏｍｉｎ；ＤｅｎｇＣｈａｎｇｌｉｅ；ＬｕｏＱｉａｎ（ＤｅｐａｒｔｍｅｎｔｏｆＭｉｎｅｒａｌＥｎｇｉｎｅｅｒｉｎｇ，...

关键词： batch sedimentation curve thickener unit area underflow concentration

A SCHWARZ LEMMA FOR HARMONIC FUNCTIONS IN THE REAL unit BALL

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2019年第5期39卷 1339-1344页

作者： Shaoyu DAI Huaihui CHEN School of Mathematics Southeast University Nanjing 210096 China Department of Mathematics Jinling Institute of Technology Nanjing 211169 China Department of Mathematics Nanjing Normal University Nanjing 210097 China

We establish a precise Schwarz lemma for real-valued and bounded harmonic functions in the real unit ball of dimension n. This extends Chen's Schwarz-Pick lemma for real-valued and bounded planar harmonic mapping.

关键词： harmonic functions Schwarz-Pick lemma unit ball

Superconductivity above 28K in single unit cell FeSe ?lms interfaced with GaO_(2-δ) layer on NdGaO_3(110)

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2019年第8期64卷 490-494页

作者： Haohao Yang Guanyu Zhou Yuying Zhu Guan-Ming Gong Qinghua Zhang Menghan Liao Zheng Li Cui Ding Fanqi Meng Mohsin Rafique Heng Wang Lin Gu Ding Zhang Lili Wang Qi-Kun Xue State Key Laboratory of Low-Dimensional Quantum Physics Department of Physics Tsinghua University Laboratory for Advanced Materials & Electron Microscopy Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Collaborative Innovation Center of Quantum Matter

The discovery of high temperature superconductivity in single unit cell(UC)FeSe on TiO2-δterminated perovskite SrTiO3(001)substrates[1]has attracted intensive attention on searching for new superconducting systems wi... 详细信息

关键词： Ga 110 lms interfaced with GaO Superconductivity above 28K in single unit cell FeSe layer on NdGaO3 UC