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Semi-valid Fuzz Testing Case Generation for Stateful Network Protocol

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Tsinghua Science and Technology 2017年第5期22卷 458-468页

作者： Rui ma Shuaimin Ren ke ma Changzhen Hu Jingfeng Xue the Beiiing key Laboratory of Software Security Engineering Technology School of SoftwareBeijing Institute of TechnologyBering 100081China the Internet Center Institute of Communication Standard Research.China Academy of Information and Communication TechnologyBering 100191China

Network protocols are divided into stateless and stateful. Stateful network protocols have complex communication interactions and state transitions. However, the existing network protocol fuzzing does not support state transitions very well. This paper focuses on this issue and proposes the Semi-valid Fuzzing for the Stateful Network Protocol （SFSNP）. The SFSNP analyzes protocol interactions and builds an extended finite state machine with a path marker for the network protocol; then it obtains test sequences of the extended finite state machine, and further performs the mutation operation using the semi-valid algorithm for each state transition in the test sequences; finally, it obtains fuzzing sequences. Moreover, because different test sequences may have the same state transitions, the SFSNP uses the state transition marking algorithm to reduce redundant test cases. By using the stateful rule tree of the protocol, the SFSNP extracts the constraints in the protocol specifications to construct semi-valid fuzz testing cases within the sub-protocol domain, and finally forms fuzzing sequences. Experimental results indicate that the SFSNP is reasonably effective at reducing the quantity of generated test cases and improving the quality of fuzz testing cases. The SFSNP can reduce redundancy and shorten testing time.

关键词： network protocol fuzzing extended finite state machine test sequence state transition markingalgorithm semi-valid algorithm

Structure and properties of an ultra-high strength 7xxx aluminum alloy contained Sc and Zr

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Journal of University of Science and Technology Beijing 2008年第3期15卷 276-279页

作者： Xiaoyuan Dai Changqing Xia Xiaomin Peng ke ma School of materials Science and Engineering Central South University Changsha 410083 China School of materials Science and Engineering Changsha University of Science and Technology Changsha 410076 China

An ultra-high strength aluminum alloy was produced by casting and then extruded to rods. The effect of heat treatment on the microstructure and mechanical properties of the alloy was investigated. After single ageing （120℃, 24 h）, the tensile strength was 812.4 MPa and the elongation was 6.2%. After retrogression reaging （RRA）, the tensile strength was 751.2 MPa and the elongation was 6.4%. The strengthening mechanism is considered as fine grain strengthening, substructure strengthening and dispersion strengthening by Al3（Sc, Zr）.

关键词： aluminum alloy scandium zirconium microstructure mechanical properties strengthening mechanism

Research Status and Strategies for Cognitive Function in Schizophrenia

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上海精神医学 2018年第3期30卷 199-201页

作者： ke ma Chuan SHI Peking University Sixth Hospital Beijing China

Cognition is divided into neurocognition and social cognition,both of which are interconnected with each other and yet are mutually ***,which is based on neuroanatomical structures,function connections,neuroelectrophy... 详细信息

关键词：精神分裂症认知功能神经解剖学神经功能认知过程生物学社会大脑

Deep-sea rock mechanics and mining technology:State of the art and perspectives

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International Journal of Mining Science and Technology 2023年第9期33卷 1083-1115页

作者： Zenghui Liu Kai Liu Xuguang Chen Zhengkuo ma Rui Lv Changyun Wei ke ma Engineering Research Center of Dredging Technology of Ministry of Education College of Mechanical and Electrical EngineeringHohai UniversityChangzhou 213022China Department of Engineering Science University of OxfordParks RoadOxford OX13PJUK College of Engineering Ocean University of ChinaQingdao 266100China State key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China

The review covers the development and the state of the art in deep-sea mining rock mechanics,equipment and *** begins by introducing the significance of deep-sea mining,the types and geographical distribution of deep-sea *** 2 reviews the mechanical properties and fracture mechanism of seabed and related continental rocks,which contributes to the advancement of relevant technologies and ***-sea mining systems developed by coastal countries are presented in Section *** mineral collection systems are critically assessed in Section *** mining vehicle is reviewed by walking mechanism and controlling system in Section *** Section 6,the development of subsea lifting system is detailed by dividing it into hydraulic and pneumatic lifting modes,and some technical problems in the lifting system are *** in-depth description of surface support systems is presented in Section 7,which includes the deep-sea mining ship,dynamic positioning system,heave compensation system,launch and retrieval system,mineral disposing system as well as the storage and transferring *** 8 discusses the challenges in the deep-sea mining,in terms of natural occurrence conditions,international legal framework and cooperative mining,environmental protection and economic benefits,***,a brief summary and some aspects of prospective research are presented in Section 9.

关键词： Deep-sea mining Deep-sea minerals Seabed mineral collection system Subsea mining vehicle Subsea lifting system

Effects of trace Ca/Sn addition on corrosion behaviors of biodegradable Mg-4Zn-0.2Mn alloy

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Journal of magnesium and Alloys 2018年第1期6卷 1-14页

作者： Wenbo Du ke Liu ke ma Zhaohui Wang Shubo Li College of materials Science and Engineering Beijing University of TechnologyBeijing 100124PR China

The effects of alloying elements of Ca/Sn on corrosion behaviors of the as-cast Mg-4Zn-0.2Mn alloy were investigated by immersion tests and electrochemical *** results indicated that the average corrosion rate value of the Mg-4Zn-0.2Mn-Ca alloy was∼0.31 mm/year in Hank’s physiological solution for 40 days,and corrosion resistance increased for the specimens containing Ca element rather than that containing Sn because of the higher breakdown potential value,lower current density and deactivated corrosion rate,which was ascribed to a formation of the uniformly distributed Mg-Zn-Ca ternary phase.

关键词： Mg-Zn-Mn alloy Corrosion behaviors Hank’s physiological solution Electrochemical test

Activity of Stress-related Antioxidative Enzymes in the Invasive Plant Crofton Weed(Eupatorium adenophorum)

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Journal of Integrative Plant Biology 2007年第11期49卷 1555-1564页

作者： Ping Lu Wei-Guo Sang ke-Ping ma key Laboratory of Vegetation Ecology and Environment Change Institute of Botany the Chinese Academy of Sciences Beijing 100093 China Resources and Environmental Sciences College Northeast Agrfcultural University Harbin 150030 China

Crofton weed is an invasive weed in southwestern China. The activities of several antioxidative enzymes involved in plant protection against oxidative stress were assayed to determine physiological aspects of the crofton weed that might render the plant vulnerable to environmental stress. Stresses imposed on crofton weed were heat （progressively increasing temperatures： 25 ℃, 30 ℃, 35 ℃, 38℃ and 42 ℃ at 24 h intervals）, cold （progressively decreasing temperatures： 25 ℃, 20 ℃, 15℃, 10 ℃ and 5℃ at 24h intervals）, and drought （without watering up to 4days）. The three stresses induced oxidative damage as evidenced by an increase in lipid peroxidation. The effect varied with the stress imposed and the length of exposure. The activity of superoxide dismutase （SOD） increased in response to all stresses but was not significantly different from the controls （P 〈 0.05） when exposed to cold stress. Catalase （CAT） activity decreased in response to heat and drought stress but increased when exposed to cold conditions. Guaiacol peroxidase （POD） and glutathione reductase （GR） activities increased in response to cold and drought but decreased in response to heat stress. The activity of ascorbata peroxidase （APX） responded differently to all three stresses. Monodehydroascorbate reductase （MDHAR） activity decreased in response to heat and drought, and slightly increased in response to the cold stress but was not significantly different from the controls （P 〈 0.05）. The activity of dehydroascorbata reductase （DHAR） increased in response to all three stresses. Taken together, the co-ordinate increase of the oxygen-detoxifying enzymes might be more effective to protect crofton weed from the accumulation of oxygen radicals at low temperatures rather than at high temperatures.

关键词： antioxidative enzymes crofton weed invasive plant stress.

Differential Responses of the Activities of Antioxidant Enzymes to Thermal Stresses between Two Invasive Eupatorium Species in China

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Journal of Integrative Plant Biology 2008年第4期50卷 393-401页

作者： Ping Lu Wei-Guo Sang ke-Ping ma key Laboratory of Vegetation and Environment Change Institute of Botany the Chinese Academy of Sciences Beijing 100093 China Resources and Environmental Sciences College Northeast Agricuitural University Harbin 150030 China

The effect of thermal stress on the antioxidant system was investigated in two invasive plants, Eupatorium adenophorum Spreng. and E. odoratum L. The former is sensitive to high temperature, whereas the latter is sensitive to low temperature. Our aim was to explore the relationship between the response of antioxidant enzymes and temperature in the two invasive weeds with different distribution patterns in China. Plants were transferred from glasshouse to growth chambers at a constant 25 ℃for I week to acclimatize to the environment. For the heat treatments, temperature was increased stepwise to 30, 35, 38 and finally to 42 ℃. For the cold treatments, temperature was decreased stepwise to 20, 15, 10 and finally to 5 ℃. Plants were kept in the growth chambers for 24 h at each temperature step. In E. adenophorum, the coordinated increase of the activities of antioxidant enzymes was effective in protecting the plant from the accumulation of active oxygen species （AOS） at low temperature, but the activities of catalase （CAT）, guaiacol peroxidase （POD）, ascorbate peroxidase （APX）, glutathione reductase （GR）, and monodehydroascorbate reductase （MDAR） were not accompanied by the increase of superoxide dismutase （SOD） during the heat treatments. As a result, the level of lipid peroxidation in E. adenophorum was higher under heat stress than under cold stress. In E. odoratum, however, the lesser degree of membrane damage, as indicated by low monodehydroascorbate content, and the coordinated increase of the oxygen. Datoxifying enzymes were observed in heat-treated plants, but the antioxidant enzymes were unable to operate in cold stress. This indicates that the plants have a higher capacity for scavenging oxygen radicals in heat stress than in cold stress. The different responses of antioxidant enzymes may be one of the possible mechanisms of the differences in temperature sensitivities of the two plant species.

关键词： antioxidant enzyme system cold stress Eupatorium adenophorum Eupatorium odoratum heat stress invasive plants.

Effect of temperature on the passivation behavior of steel rebar

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International Journal of Minerals,Metallurgy and materials 2014年第5期21卷 455-461页

作者： Shan-meng Chen Bei Cao Yin-shun Wu ke ma School of materials Science and Engineering University of Science and Technology Beijing

Steel rebar normally forms an oxide or rusty skin before it is embedded into concrete and the passivation properties of this skin will be heavily influenced by temperature. To study the effect of temperature on the passivation properties of steel rebar under different surface conditions, we conducted scanning electron microscopy （SEM） observations and electrochemical measurements, such as measurements of the free corrosion potential and polarization curves of HPB235 steel rebar. These measurements identified three kinds of surfaces： polished, oxide skin, and rusty skin. Our results show that the passivation properties of all the surface types decrease with the increase of temperature. Temperature has the greatest effect on the rusty-skin rebar and least effect on the polished steel rebar, because of cracks and crevices on the mill scale on the steel rebar＇s surface. The rusty-skin rebar exhibits the highest corrosion rate because crevice corrosion can accelerate the corrosion of the steel rehar, particularly at high temperature. The results also indicate that the threshold temperatures of passivation for the oxide-skin rebar and the rusty-skin rebar are 37℃and 20℃, respectively.

关键词： steel rebar steel corrosion passivation temperature

Penetration Estimation of Gma Backing Welding Based on Weld Pool Geometry Parameters

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Chinese Journal of Mechanical Engineering 2019年第3期32卷 134-144页

作者： Junfen Huang Long Xue Jiqiang Huang Yong Zou ke ma Opto-Mechatronic Equipment Technology Beijing Area major Laboratory Beijing Institute of Petrochemical Technology

Penetration estimation is a prerequisite of the automation of backing welding based on vision sensing technology. However, the arc interference in welding process leads to the difficulties of extracting the weld pool characteristic information, which brings great challenges to the penetration estimation. At present, most researches focus on the extraction of weld pool geometry parameters, and the visual sensing systems are complex in structure and complicated in the image processing algorithms. The research of penetration estimation based on weld pool geometry parameters is still in the exploratory stage. The purpose of this paper is to research the relationship between the weld pool geometry parameters and the penetration during backing welding and to estimate penetration using the weld pool geometry parameters. A passive vision sensing test system for gas metal arc (Gma) backing welding was established. An image processing algorithm was developed to extract the weld pool geometry parameters, namely, the area, maximum width and length, half-length, length-width ratio and advancing contact angle (simplified as AWP, MWWP, MLWP, HLWP, LWR and ACA, respectively). The corresponding relationships between the weld pool geometry parameters and the penetration state were explored by analysing their changes with the welding current and speed. The distribution of the weld pool geometry parameters corresponding to penetration was determined. When the AWP of the weld pool is within a certain range and the values of LWR and ACA are close to their maximum and minimum respectively, the penetration is in good condition. A mathematical model with the weld pool geometry parameters as independent variables and the back-bead width (the indicator of the penetration state) as a dependent variable was established based on multivariable linear regression analysis, and relevant statistical tests were carried out. Multivariable linear regression equations for the weld pool geometry parameter

关键词： Welding automation Passive vision sensing Weld pool geometry parameters Penetration state mathematical model