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The automatic detection of engineering drawing modifications made by other designers is central to improving CAD/CAPP working efficiency levels. Engineering drawings include numerous entities, but only a few entities are modified. It is difficult for designers to identify modified entities in a complex drawing. This paper presents a novel means of detecting entities in engineering drawings created by other designers that employs semi-fragile watermark technologies. Modifications will change embedded watermarks. Consequently, detection is realized by analyzing changes. The approach was implemented, and the experimental results demonstrate that the method is reliable and can accurately detect entities that have been modified, deleted and added.

In this paper, laser beam melting technology is applied to the manufacture of defined porous metal structures using the exposure strategies of the machine manufacturer. It turns out that specific filter characteristics such as density, permeability, pore size, porosity, and shear strength are comparable to conventionally-made porosities [1]. To overcome some restrictions imposed by the default settings of the machine manufacturer, and to manufacture ultra-lightweight products, our own investigations -such as direct slicing -lead to an alternative exposure strategy for the laser. Here unique exposure lines, with their corresponding start and end points, are individually designed according to their practical needs. Even though this procedure is very complex and time-consuming, it leads to new possibilities for the perfusion of liquid or gaseous fluids that run through metal walls.In summary, the adjustment of the functional porosity of laser beam melted parts made of metal material is the focus of this investigation; and with it, the variation and determination of the proper process parameters is essential. With the easily adjustable porosities and pore sizes that are investigated, combined with the geometric freedom of laser beam melting, very complex elements can be integrated into one part; and this also leads to new fields of application. OPSOMMINGLaserstraal smelttegnologie word toegepas op die vervaardiging van gedefinieerde poreuse metaalstrukture deur die gebruik van die blootstellingstrategieë van die toerustingvervaardiger.Die blyk dat spesifieke filtereienskappe soos digtheid, deurlaatbaarheid, poreusheid en skuifsterkte vergelykbaar is met konvensioneel vervaardigde poreushede. Om sommige beperkings as gevolg van die vervaardiger se verstekverstellings te oorkom en om ultraligte produkte te vervaardig is 'n alternatiewe blootstellingstrategie vir die laser ontwikkel. Unieke blootstellinglyne, met hulle ooreenstemmende begin-en eindpunte, is individueel ontwerp volgens hulle praktiese behoeftes. Al is hierdie prosedure ingewikkeld en tydrowend, lei dit tot nuwe moontlikhede vir die perfusie van vloeistof of gasagtige vloeiers wat deur metaalwande vloei.Opsommend, die fokus van die ondersoek is die verstelling van die funksionele porositeit van laserstraal gesmelte metaal onderdele, en saam met dit, is die variasie en bepaling van die gepaste proses parameters noodsaaklik. Met die maklik verstelbare porositeit wat hier ondersoek word, tesame met die geometriese vryheid van laserstraal smelting, kan komplekse elemente in een onderdeel geïntegreer word, en dit gee aanleiding tot nuwe toepassings.

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