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Science China(Information Sciences) 2017年第11期60卷 265-267页

作者： Shuang HU Jihong ZHU department of computer Science and technology Tsinghua University

The extension of flight envelope to high angles of attack has been a key requirement for modern *** combat aircrafts should be provided with super maneuver performance to improve operational *** this case,the incidence of aircraft could be very large,even reaching post stall *** aerodynamics show strong nonlinear and unsteady characteristics in the flight of high incidence,which are caused by complex flow structures such as attached flow separation and vortex burst[1].The unsteady aerodynamic modeling at high incidences is helpful to control law design and flight simulation which has great practical *** its progress over two decades,unsteady aerodynamic models can

关键词： wind tunnel operational effectiveness flow separation flight envelope complex flow

Thermal insulation and cooling properties of thermal barrier coatings of flame baffles

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Journal of Beijing Institute of technology 2011年第4期20卷 558-563页

作者：许卫宝刘保果宋遒志 School of Shipbuilding Engineering Harbin Engineering University Navy armament department School of MechatronicalEngineering Beijing Institute of Technology

In order to study the thermal insulation and cooling properties of thermal barrier coatings of a flame baffle,several ZrO2 thermal barrier coatings with different thicknesses were prepared on the surface of aluminium-alloy flame-baffle samples by plasma *** relations between temperature and time of these samples were tested when they were heated by combustion *** relations between temperature of the coatings and the sample bodies and time were also tested when the samples at high temperatures were cooled by *** experimental results indicated that ① the thicker the thermal barrier coatings,the better the thermal insulation effect of the thermal barrier;② the higher the temperature,the more significant of the thermal insulation of the thermal ***,in the case of water-cooling,the cooling rate of the coatings was greatly subject to the plate body and the cooling rate of coatings below 1.0mm was equivalent to that of the plate body.

关键词： flame baffle thermal barrier coating cooling factors

A new system for distributed machine learning

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National Science Review 2018年第3期5卷 303-304页

作者： Jianyong Wang department of computer Science and technology Tsinghua University

Machine learning has become a primary mechanism for mining structured information and knowledge from data collections,turning them into automatic predictions and actionable hypotheses for diverse *** the increasing data from various sources,conventional machine learning research and development are now challenged by the growing prevalence of Big *** rise of

关键词： A new system for distributed machine learning Server

A formally verified transformation to unify multiple nested clocks for a Lustre-like language

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Science China(Information Sciences) 2019年第1期62卷 208-210页

作者： Gang SHI Yucheng ZHANG Shu SHANG Shengyuan WANG Yuan DONG Pen-Chung YEW department of computer Science and technology Tsinghua University department of computer Science and Engineering University of Minnesota

Multiple nested clocks is a major language feature in synchronous data-flow languages such as Lustre [1]. To build a formally verified compiler for such a language, it is a common practice to compile the source program to a C-like program first before compiling it to low-level machine-dependent code using a formally verified backend compiler

关键词： A formally verified transformation to unify multiple nested clocks for a Lustre-like language cycle

Design and hovering control of a twin rotor tail-sitter UAV

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Science China(Information Sciences) 2019年第9期62卷 185-187页

作者： Wufan WANG Jihong ZHU Minchi KUANG Xiaming YUAN Yunfei TANG Yaqing LAI Lyujie CHEN Yunjie YANG department of computer Science and technology Tsinghua University

The tail-sitter unmanned aerial vehicles (UAVs)combine the vertical takeoff and landing (VTOL)capabilities of rotary-wing UAVs and the efficient long-distance flight capability of fixed-wing *** compared with other hybrid aircraft configurations such as tilt-rotor [1] and tilt-wing [2]UAVs, the tail-sitter UAV possesses the simplest configuration and requires no extra mechanisms for performing the VTOL maneuver. This brings several benefits including high payload and low susceptibility to malfunctions.

关键词： Design and hovering control of a twin rotor tail-sitter UAV pro

Curvature-direction measures for 3D feature detection

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Science China(Information Sciences) 2013年第9期56卷 56-64页

作者： LI JinJiang FAN Hui department of computer Science and technology Tsinghua University School of computer Science and technology Shandong Institute of Business and Technology

In this paper, we propose a new robust feature extraction algorithm for 3D models based on principal curvature direction. Generally, the feature regions tend to be more noisy, so it demands a robust technique to handle features effectively. Because the integral invariants are robust against noise, the principal curvature information is estimated based on principal component analysis. After fuzzy filtering of the principal curvature direction, it becomes a good description of the geometric discontinuity. Compared with the curvature values, the impact of noise on the principal curvature direction is small. Therefore, feature extraction based on principal curvature direction is more robust and accurate. The experimental results show that the proposed algorithm can efficiently extract feature and distinguish noise.

关键词： feature extraction integral invariants principal curvature direction

Package Coupling Measurement in Object-Oriented Software

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Journal of computer Science & technology 2009年第2期24卷 273-283页

作者： Varun Gupta Jitender Kumar Chhabra department of computer Engineering National Institute of TechnologyKurukshetra

The grouping of correlated classes into a package helps in better organization of modern object-oriented software. The quality of such packages needs to be measured so as to estimate their utilization. In this paper, new package coupling metrics are proposed, which also take into consideration the hierarchical structure of packages and direction of connections among package elements. The proposed measures have been validated theoretically as well as empirically using 18 packages taken from two open source software systems. The results obtained from this study show strong correlation between package coupling and understandability of the package which suggests that proposed metrics could be further used to represent other external software quality factors.

关键词： package coupling metrics object-oriented software understandability

Towards automated software model checking using graph transformation systems and Bogor

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第8期10卷 1093-1105页

作者： Vahid RAFE Adel T.RAHMANI department of computer Engineering Iran University of Science and Technology

Graph transformation systems have become a general formal modeling language to describe many models in software development *** modeling of dynamic systems and model-to-model transformations are only a few examples in which graphs have been used to software *** even the perfect graph transformation system must be equipped with automated analysis capabilities to let users understand whether such a formal specification fulfills their *** this paper,we present a new solution to verify graph transformation systems using the Bogor model *** attributed graph grammars(AGG)-like graph transformation systems are translated to Bandera intermediate representation(BIR),the input language of Bogor,and Bogor verifies the model against some interesting properties defined by combining linear temporal logic(LTL) and special-purpose graph *** results are encouraging,showing that in most cases our solution improves existing approaches in terms of both performance and expressiveness.

关键词： Graph transformation Verification Bogor Attributed graph grammars (AGG) Software model checking

A Comprehensive and Adaptive Trust Model for Large-Scale P2P Networks

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Journal of computer Science & technology 2009年第5期24卷 868-882页

作者：李小勇桂小林 department of computer Science and technology Xi'an Jiaotong University

Based on human psychological cognitive behavior, a Comprehensive and Adaptive Trust （CAT） model for largescale P2P networks is proposed. Firstly, an adaptive trusted decision-making method based on HEW （Historical Evidences Window） is proposed, which can not only reduce the risk and improve system efficiency, but also solve the trust forecasting problem when the direct evidences are insufficient. Then, direct trust computing method based on IOWA （Induced Ordered Weighted Averaging） operator and feedback trust converging mechanism based on DTT （Direct Trust Tree） are set up, which makes the model have a better scalability than previous studies. At the same time, two new parameters, confidence factor and feedback factor, are introduced to assign the weights to direct trust and feedback trust adaptively, which overcomes the shortage of traditional method, in which the weights are assigned by subjective ways. Simulation results show that, compared to the existing approaches, the proposed model has remarkable enhancements in the accuracy of trust decision-making and has a better dynamic adaptation capability in handling various dynamic behaviors of peers.

关键词： P2P networks dynamic trust model IOWA operator adaptability

PALES: Optimizing Secure Data Deletion in SSDs via Page Group and Reprogram Speedup

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Chinese Journal of Electronics 2022年第1期31卷 40-51页

作者： NIE Shiqiang WU Weiguo ZHANG Chi ZHANG Chen department of computer Science and technology Xi'an Jiaotong University

As solid-state drives(SSD) have been widely adopted, secure data deletion becomes an essential component for ensuring user privacy, preventing sensitive data leakage. Due to the erase-before-write property,erasure operation and scrub operation substituting for overwriting technologies are proposed to meet the requirements. However, both methods bring the severe page-copying issue, declining read/write performance, and shortening the lifetime of SSD. In this paper, this issue is alleviated by reserving pages at the page allocation stage to mitigate program disturbance and increasing program step voltage during reprogramming operation to reduce the reprogram latency. The proposed scheme is evaluated by a series of experiments; the results show that the proposed scheme could achieve significant deletion time reduction and alleviate page-copying overhead.

关键词： reprogramming operation storage management solid-state drives SSD flash memories page group page-copying overhead erase-before-write property secure data deletion PALES data privacy erasure operation page allocation stage user privacy security of data program step voltage sensitive data leakage reprogram speedup