计算机绘制船图时线型、线宽等属性的控制方法

给出了使用AutoCAD 2000绘制船图时所用线型的定义及建立这些线型的方法,阐述了用HP DesignJet430绘图仪出图时对线型、线宽属性的编辑及控制方法,解决了出图时的许多实际问题,这些方法对提高船图出图质量十分有效。

MAINTENANCE LEVEL DECISION OF AERO-ENGINE BASED ON VPRS THEORY

An aero-engine is a typically repairable and complex system and its maintenance level has a close relationship with the maintenance cost. The inaccurate measurement for the maintenance level of an aero-engine can induce higher overhaul maintenance costs. Variable precision rough set （VPRS） theory is used to determine the maintenance level of an aero-engine. According to the relationship between condition information and performance parameters of aero-engine modules, decision rules are established for reflecting the real condition of an aeroengine when its maintenance level needs to be determined. Finally, the CF6 engine is used as an example to illustrate the method to be effective.

Stabilization design for continuous-time Takagi-Sugeno fuzzy systems based on new relaxed conditions

This paper deals with the problem of stabilization design for a class of continuous-time Takagi-Sugeno（T-S）fuzzy systems.New stabilization conditions are derived based on a relaxed approach in which both fuzzy Lyapunov functions and staircase membership functions are used.Through the staircase membership functions approximating the continuous membership functions of the given fuzzy model,the information of the membership functions can be brought into the stabilization design of the fuzzy systems,thereby significantly reducing the conservativeness in the existing stabilization conditions of the T-S fuzzy systems.Unlike some previous fuzzy Lyapunov function approaches reported in the literature,the proposed stabilization conditions do not depend on the time-derivative of the membership functions that may be the main source of conservatism when considering fuzzy Lyapunov functions analysis.Moreover,conditions for the solvability of the controller design are written in the form of linear matrix inequalities,but not bilinear matrix inequalities,which are easier to be solved by convex optimization techniques.A simulation example is given to demonstrate the validity of the proposed approach.

Acacia mangium and Eucalyptus urophylla in Northern Vietnam： The Relationship between Silvicultural Activity and Quality of Stand

This paper sets out to determine the link between socio-economic attributes of smallholders, silvicultural activity and the stand quality of Acacia mangium and Eucalyptus urophylla plantations in two unrelated communes in Phu Tho province, Vietnam. The necessary data was collected by interviewing the smallholders and conducting inventory of the stands. The data was analyzed with descriptive statistics, Mann-Whitney tests and Spearman correlations. More silvicultural practices were conducted by A. mangium planters with larger areas. Most of the smallholders practiced the suggested silvicultural activities. Productivity was affected by pruning in medium quality sites. This research recommends that smallholders were supported with incentives for the plantation establishment, education for smallholders in silvicultural techniques, organization and development activities for the wider market.

Attribute-Based Authenticated Group Key Management Protocol for Mobile Peer-to-Peer Network

The authentication and privacy of a group member is important in multicast communication. This paper proposes a privacy-preserving authenticated group-key management protocol for the Mobile Peer-to-Peer Network （ MP2PN ）. The MP2PN contains some super peers and each super peer controls a subgroup composed of regular peers. An efficient attribute-based signature based on Cipertext-Policy Attribute-Based Encryption （CP-ABE） is proposed and used in this group-key rmnagement protocol to authenticate a peer＇s at- tributes and identity. A peer can be described by a set of attributes or one unique special identity at- tribute. Peers that have some attributes in common can form a group and conmmnicate with each other anonymously and securely. Any super peer can initiate a group and act as a group controller. The group controller can authenticate a peer＇s attributes and identity as well as remove malicious peers. Any peer with attributes that rmtches the access structure can join the group and provide its input to form the group key. The proposed protocol pro- vides backward and forward secrecy. The sinmlation results show that this protocol is applicable for mobile devices and can meet the MP2PN requirements of group communication.

Simulation of pressure effects on hot isostatic pressing of stainless steel powder

To investigate the effects of pressure on the hot isostatic pressing(HIP) process of a stainless steel powder,density distribution and deformation of the powder at four different applied pressure levels were predicted and compared by using finite element method(FEM).Constitutive relations of porous compacts during HIP process were derived based on the yield criterion of porous metal materials.Thermo-mechanical coupling calculations were carried out by the MSC.Marc.Densification mechanisms were studied through evolutions of relative density,equivalent plastic strain and equivalent viscoplastic strain rate for compacts.The simulation results were also compared with experimental data.The results show that the densification rate and final density of compacts increase dramatically with the increase in the applied pressure level when it is below 100 MPa during HIP process,and the creep for compacts evolves into steady stage with the improvement of density.

Toeplitz operators on Fock-Sobolev spaces with positive measure symbols

We discuss Toeplitz operators on Fock-Sobolev space with positive measure symbols.By FockCarleson measure,we obtain the characterizations for boundedness and compactness of Toeplitz operators.We also give some equivalent conditions of Schatten p-class properties of Toeplitz operators by Berezin transform.