Liquid crystal spatial light modulator with optimized phase modulation ranges to display multiorder diffractive elements

Postprint (published version

First-order and multi-order diffractive lens using a device with 8P phase modulation range

Postprint (published version

3x3 Multibeam Network for a Triangular Array of Three Radiating Elements

A multibeam antenna study based on Butler network will be undertaken in this document. These antenna designs combines phase shift systems with multibeam networks to optimize multiple channel systems. The system will work at 1.7 GHz with circular polarization. Specifically, result simulations and measurements of 3 element triangular subarray will be shown. A 45 element triangular array will be formed by the subarrays. Using triangular subarrays, side lobes and crossing points are reduced

Roadmap on optical security

Postprint (author's final draft

Image encryption system based on a nonlinear joint transform correlator for the simultaneous authentication of two users

We propose a new encryption system based on a nonlinear joint transform correlator (JTC) using the information of two biometrics (one digital fingerprint for each user) as security keys of the encryption system. In order to perform the decryption and authentication in a proper way, it is necessary to have the two digital fingerprints from the respective users whose simultaneous authentication is pursued. The proposed security system is developed in the Fourier domain. The nonlinearity of the JTC along with the five security keys given by the three random phase masks and the two digital fingerprints of the two users allow an increase of the system security against brute force and plaintext attacks. The feasibility and validity of this proposal is demonstrated using digital fingerprints as biometrics in numerical experiments.Peer ReviewedPostprint (published version

Effects of using an encrypted image corrupted by noise and occlusion in a security system based on joint transform correlator and Gyrator transform

Postprint (published version

Image quality and security through nonlinear joint transform encryption

Postprint (published version

Matrix Product States: Symmetries and Two-Body Hamiltonians

We characterize the conditions under which a translationally invariant matrix product state (MPS) is invariant under local transformations. This allows us to relate the symmetry group of a given state to the symmetry group of a simple tensor. We exploit this result in order to prove and extend a version of the Lieb-Schultz-Mattis theorem, one of the basic results in many-body physics, in the context of MPS. We illustrate the results with an exhaustive search of SU(2)--invariant two-body Hamiltonians which have such MPS as exact ground states or excitations.Comment: PDFLatex, 12 pages and 6 figure

Four Wheelchair-User Architects

It certainly seems like a fortuitous accident that four wheelchair users have ended up studying at the same school of architecture, at almost the same time. Maybe it is even the same kind of twisted fate that has confined us to a wheelchair in the first place, as none of us was born in it. With different ages, backgrounds, interests and sets of difficulties to master, we committed ourselves to initiate careers in architecture several years ago. Accessibility issues, especially in terms of mobility, have (always) been an intrinsic and fundamental part of our approach to academic projects, and they will most certainly continue to maintain a strong presence in our professional lives. This book reflects a set of principles and motivations that fuel our daily concerns. First and foremost, it is our desire to introduce people to a wide range of viewpoints, other ways of perceiving the environment in general, and architecture in particular. Furthermore, we aspire to break nonsensical stereotypes, particularly those that claim everything dealing with accessibility and universal design is ugly or sad, or that it only exists to assist a ridiculously small chunk of the population that is (un)fortunately affected by some kind of affliction. In terms of academic training, we’d like to voice our concern that very little is being done to approach architecture through anything other than a pure ocularcentric bias that precludes other basic concepts. If anything, architecture is created by means of and for the entire human body. Finally, it is also our wish to present our final theses projects, not because they are particularly extraordinary or look especially nice, but because they were conceived in a unique way: they were created with a view to fostering the closest possible relationship between user and designer