Hiding Information in Multiple Level-line Moirés

Secure documents often comprise an information layer that is hard to reproduce. Moiré techniques for the prevention of counterfeiting rely on the superposition of an array of transparent lines or microlenses on top of a base layer containing hidden information. Level-line moirés consist of shapes that appear to be beating upon relative translation of a revealing grating on top of a base, in which the desired information is encoded. Usually, the base only contains the information corresponding to one moiré. In order to increase the difficulty of counterfeiting, we use tessellations to incorporate two or more moirés within the same layer. With the method we propose, the information corresponding to up to seven level-line moirés can be embedded within a single base layer. The moirés are recovered with a revealer printed on a transparency or with an array of cylindrical lenses. This method is general and can be extended to other fabrication technologies

Moiré effects produced by superpositions of micro-lens arrays

Moiré effects result from the superimposition of repetitive structures. The beauty of these moirés comes from the fact that macroscopic shapes seem to appear from the superposition of layers containing microscopic patterns. In addition, the moirés are dynamic and change when the layers are moved, or when the fabricated moiré samples are tilted. Aside from their visual appeal, moirés can also be used in security application, where their requirement of high resolution and fabrication accuracy are interesting to fight counterfeiting. In the context of this thesis, we focus on three moiré types. The first is called the level-line moiré. It displays a static shape whose intensities or colours vary depending on the superposition conditions of its two constituting layers. One layer is a grating of straight lines, while the other is a grating of the same period, to which distorsions have been purposefully applied. The distortions are dictated by an elevation profile, whose level lines are visible when the two layers are superposed. The second moiré type we cosider is the 1D moiré. The layers to be superposed are the base and the revealer. The base is a grating of rectangular tiles that contain the same symbol, shape or text. The revealer is a grating of lines, whose period is slightly different from that of the base. The base is only seen through the transparent parts of the revealer and is therefore sampled only at specific locations. The 1D moiré shape is thus a magnified version of the base tiles and is repeated in a given direction. When the revealer is translated relative to the base, the moiré shapes translate in a certain direction. Finally, 2D moirés are obtained in a similar fashion to the 1D moirés. The base tile is compressed and replicated in both directions to create the base array. Similarly, the revealer is an array of dots or sampling holes instead of lines. The moiré shape is a magnified version of the base tile and it can move in any direction, depending on the displacement of the revealer. Moreover, each of these moirés can be modified by applying transformations to the moirés or to their constituting layers. This is for example how spiraling moirés are designed. We have expanded the range of moiré features by creating a combination of these moiré types. The new moiré effects we created combine level-line moiré and 1D moiré or level-line moiré and 2D moiré. The moiré shapes can now both move and display varying intensities when the revealer is translated relative to the base. To obtain moiré samples, several methods can be employed. First, the two layers can be printed on transparencies. Although a fast method, the resulting moirés lack intensity and cannot be obtained at very high resolutions. An alternative is to combine a printed (or micro-fabricated) base with a lens-based revealer. The micro-lens arrays increase the dynamic range of the moirés, which is particularly important for 1D and 2D moirés. Finally, the new method we have developed relies on micro-fabrication technologies to fabricate moiré samples that are only made of transparent materials. In these new samples, both the base and the revealer are made of micro-lenses, which are fabricated on both sides of a transparent substrate. The three moiré types can be fabricated with this method and the samples are now brighter, more intriguing and the moiré intensities depend strongly on the viewing and illumination conditions

Synergy Effects through Cooperation: Background, Tasks, and Potentials of the Project Fodako

Vor dem Hintergrund der zunehmenden Bedeutung von Open-Data-Ansätzen und neuen Anforderungen an das Forschungsdatenmanagement (FDM) vonseiten der Förderinstitutionen, streben Forschende und Institutionen einen Wandel bislang praktizierter Vorgehensweisen beim FDM an. In einer universitären Kooperation von drei Rechenzentren und drei Universitätsbibliotheken zielt das Projekt Forschungsdatenmanagement in Kooperation (FoDaKo),1 darauf ab, Synergien nutzbar zu machen und Best Practices für das FDM zu entwickeln und auszutauschen. Der Beitrag gibt einen Einblick in Struktur, Maßnahmen und bislang gesammelte Erfahrungen eines Projekts zur Erforschung des Managements von Forschungsdaten in ihrem Lebenszyklus an den Universitäten Düsseldorf, Siegen und Wuppertal und ermöglicht Dritten damit die Möglichkeit der Adaption von Ansätzen für ein möglichst kosteneffizientes und nachhaltiges FDM.Against the backdrop of the increasing significance of open data approaches and newly emerging requirements in Research Data Management (RDM), imposed by funding agencies, researchers and institutions strive for an upheaval in current RDM practices. The FoDaKo project,2 comprises a collaboration of three Universities' data centres and libraries, gearing towards harnessing synergies in resources, while developing and sharing best practices in RDM throughout the data lifecycle. In this paper, we share our approach and experiences, which can inform other institutions and projects in achieving an economical and sustainable RDM

1D moiré shapes by superposed layers of micro-lenses

Two superposed layers of transparent cylindrical lenslet gratings create classical moiré fringes, when illuminated from behind. We rely on this observation to conceive special devices made of superposed lenslet gratings that produce animated moirés when they are tilted against the light. One-dimensional moirés can show a message moving back and forth along a given direction or radially expanding towards the exterior of a disk. These 1D moirés are conceived by fabricating two layers of micro-lenses on both sides of a transparent substrate. The top layer is a rectilinear grating of cylindrical lenslets and the bottom layer is an arrangement of smaller lenslets of different sizes and orientations that create a high contrast. Moirés created by superpositions of lenslets are visually striking and can be challenging to fabricate. Therefore they have a high potential for art, decoration, and document security

Synthesis of superposition shape images by light interacting with layers of lenslets

The present invention describes methods and apparatuses for creating superposition shape images by superposed base and revealing layers of lenslet gratings. The superposition shape images form a message recognizable by a human observer or by an image acquisition and computing device such as a smartphone. The superposition shape images may be created by different superposition techniques ranging from 1D moiré, 2D moiré and level-line moiré superposition techniques to lenticular image and phase shift superposition techniques. Moiré superposition techniques enable creating superposition shape images at different apparent depth levels. Applications comprise the protection of documents and valuable articles against counterfeits, the creation of eye-catching advertisements as well as the decoration of buildings and exhibitions

Level-line moirés by superposition of cylindrical microlens gratings

Two superposed layers of transparent cylindrical lenslet gratings create classical moiré fringes when illuminated from behind. We rely on this observation to conceive special devices made of superposed lenslet gratings that produce compelling beating shapes when tilted against the light. Level-line moirés are created by superposing gratings of cylindrical lenslets of the same period on both sides of a substrate and by locally shifting some of the cylindrical lenses according to the moiré theory. Depending on the illumination and the viewing conditions, constant light intensities or colors move across graphical elements or faces. Such level-line moiré samples have been fabricated and characterized to determine the optimal fabrication parameters. Thanks to their striking visual appeal and their relatively challenging fabrication, moirés created by superposition of lenslets have a high potential for document security, art, and decoration

DINI Certificate for Open Access Repositories and Publication Services 2016

Publishing is an important pillar of the advancement of scientific knowledge and of science as a whole. Among its characteristics are (a) the organization of an effective communication between scien-tists/scholars (between → authors and all potential recipients, i.e. securing an adequate dissemination), (b) a high degree of trustworthiness (e.g. with regard to priority, copyrights, authenticity, and quality of content) that is communicated to the → users of publications (i.e. the scientists/scholars), and (c) sustainability and verifiability (persistent citations, long-term availability, traceability of the steps on the way to publication). The present catalog of criteria translates these general expectations of scientific publishing into concrete minimum requirements of Open Access Repositories and Publication Services. As platforms for the publication and presentation of scientific and scholarly works these represent important hubs in the scientific communication process. As Open Access services they facilitate the dissemina-tion and democratization of knowledge. The term Open Access Repositories and Publication Services comprises the following services (see also Definitions in Appendix B): - Institutional Open Access repositories - Disciplinary Open Access repositories - Open Access journalsPeer Reviewe

DINI-Zertifikat für Open-Access-Repositorien und -Publikationsdienste 2016 [Oktober 2016]

Müller U, Scholze F, Arning U, et al. DINI-Zertifikat für Open-Access-Repositorien und -Publikationsdienste 2016 [Oktober 2016]. DINI Schriften. Vol 3. Deutsche Initiative für Netzwerkinformation (DINI); 2016.Das Publikationswesen ist ein wesentlicher Stützpfeiler des wissenschaftlichen Erkenntnisfortschritts und der Wissenschaft insgesamt. Zu seinen Kennzeichen gehören (a) die Organisation einer effektiven Kommunikation zwischen Wissenschaftler/-innen (zwischen Autor/-innen und allen potenziellen Rezipient/-innen, d. h. die Sicherstellung einer adäquaten Verbreitung), (b) ein hohes Maß an Vertrauenswürdigkeit, das den Nutzer/-innen des Publikationswesens (d. h. den Wissenschaftler/-innen) vermittelt wird (z. B. in Bezug auf das Prioritätsrecht, die Wahrung des Urheberrechts sowie die Authentizität und die inhaltliche Qualität wissenschaftlicher Arbeiten), (c) Nachhaltigkeit und Nachprüfbarkeit (dauerhafte Zitierbarkeit und langfristige Verfügbarkeit, Nachvollziehbarkeit von einzelnen Schritten auf dem Weg zur Veröffentlichung). Mit dem vorliegenden Kriterienkatalog, der dem DINI-Zertifikat zugrunde liegt, werden diese allgemeinen Erwartungen an das wissenschaftliche Publizieren in konkrete Mindestanforderungen übersetzt, die an Open-Access-Repositorien und Publikationsdienste zu stellen sind. Sie bilden als Plattformen für die Veröffentlichung und Bereitstellung wissenschaftlicher Publikationen in elektronischer Form wichtige Knotenpunkte für den wissenschaftlichen Kommunikationsprozess und tragen als Open-Access-Dienste zur Verbreitung und Demokratisierung von Wissen bei. Unter dem Begriff Open-Access-Repositorien und -Publikationsdienste werden insbesondere die folgenden Dienste zusammengefasst (siehe auch die Begriffsdefinitionen in Anhang B): * Institutionelle Open-Access-Repositorien * Fachbezogene Open-Access-Repositorien * Open-Access-Zeitschrifte

DINI-Zertifikat für Open-Access-Publikationsdienste 2019

Müller U, Scholze F, Vierkant P, et al. DINI-Zertifikat für Open-Access-Publikationsdienste 2019. DINI Schriften. Vol 3. Humboldt-Universität zu Berlin; 2019.Das Publikationswesen ist ein wesentlicher Stützpfeiler des wissenschaftlichen Erkenntnisfortschritts und der Wissenschaft insgesamt. Zu seinen Kennzeichen gehören a. die Organisation einer effektiven Kommunikation zwischen Forschenden (zwischen Autor*innen und allen potenziellen Rezipient*innen, d. h. die Sicherstellung einer adäquaten Verbreitung), b. ein hohes Maß an Vertrauenswürdigkeit, das den Nutzenden des Publikationswesens (d.h. den Forschenden) vermittelt wird (z.B. in Bezug auf das Prioritätsrecht, die Wahrung des Urheberrechts sowie die Authentizität und die inhaltliche Qualität wissenschaftlicher Arbeiten), sowie c. Nachhaltigkeit und Nachprüfbarkeit (dauerhafte Zitierbarkeit und langfristige Verfügbarkeit, Nachvollziehbarkeit von einzelnen Schritten auf dem Weg zur Veröffentlichung). Mit dem vorliegenden Kriterienkatalog werden diese allgemeinen Erwartungen an das wissenschaftliche Publizieren in konkrete Mindestanforderungen übersetzt, die an Open-Access-Publikationsdienste zu stellen sind