An introduction to the interim digital SAR processor and the characteristics of the associated Seasat SAR imagery

Basic engineering data regarding the Interim Digital SAR Processor (IDP) and the digitally correlated Seasat synthetic aperature radar (SAR) imagery are presented. The correlation function and IDP hardware/software configuration are described, and a preliminary performance assessment presented. The geometric and radiometric characteristics, with special emphasis on those peculiar to the IDP produced imagery, are described

Precise computer controlled positioning of robot end effectors using force sensors

A major problem in space applications of robotics and docking of spacecraft is the development of technology for automated precise positioning of mating components with smooth motion and soft contact. To achieve the above objective, a design method was developed for optimally placing the closed-loop poles of a discretized robotic control system at exact prescribed locations inside the unit circle of the complex z-plane. The design method combines the merits of the pole placement and the linear quadratic design approaches. The proposed design procedure is based on the assignment of one real eigenvalue or two complex conjugate (or real) eigenvalues at each design step. The method involves solutions of simple algebraic equations and this is considered to be efficient for on-line or off-line computations. Also, two methods for the linearization of the nonlinear model of a robotic manipulator were presented. Since automatic control of multi-degree freedom robotic manipulators involves high nonlinear equations of systems, a pilot project was proposed involving the control of a one-dimensional system. This simple system can be readily implemented for testing the concepts and algorithms

NeurAll: Towards a Unified Visual Perception Model for Automated Driving

Convolutional Neural Networks (CNNs) are successfully used for the important automotive visual perception tasks including object recognition, motion and depth estimation, visual SLAM, etc. However, these tasks are typically independently explored and modeled. In this paper, we propose a joint multi-task network design for learning several tasks simultaneously. Our main motivation is the computational efficiency achieved by sharing the expensive initial convolutional layers between all tasks. Indeed, the main bottleneck in automated driving systems is the limited processing power available on deployment hardware. There is also some evidence for other benefits in improving accuracy for some tasks and easing development effort. It also offers scalability to add more tasks leveraging existing features and achieving better generalization. We survey various CNN based solutions for visual perception tasks in automated driving. Then we propose a unified CNN model for the important tasks and discuss several advanced optimization and architecture design techniques to improve the baseline model. The paper is partly review and partly positional with demonstration of several preliminary results promising for future research. We first demonstrate results of multi-stream learning and auxiliary learning which are important ingredients to scale to a large multi-task model. Finally, we implement a two-stream three-task network which performs better in many cases compared to their corresponding single-task models, while maintaining network size.Comment: Accepted for Oral Presentation at IEEE Intelligent Transportation Systems Conference (ITSC) 201

The biological role of Asn-linked glycosylations of DENV-2 E protein

The envelope proteins of many viruses are glycosylated, where the glycans on the virion surface have been shown to be important, in addition to their strictly structural role, in various aspects of the virus life cycle, such as receptor-binding and escape from antibody recognition. Dengue virus (DENV) is in terms of human disease frequency the most important member of the flaviviruses, a group of small, enveloped, plus-strand RNA viruses. The four DENV serotypes differ from all other flaviviruses by the presence of two glycans on the envelope (E) protein, one linked to Asn-153, a glycosylation which is well conserved among the flaviviruses, and a second linked to Asn-67, which is unique to DENY. While the presence of glycan at Asn-153 has been shown by others to influence fusion of viral with cellular membranes, infectivity, assembly and/or release and virulence, the glycan at Asn-67 has been suggested to be critical in virus attachment to the cell surface molecule, DC-SIGN, a putative cellular receptor for DENV. In this study, I have used a reverse genetics approach to prevent glycosylation at Asn-67, Asn-153, or both carbohydrate acceptor sites, in order to investigate their physiological function(s). Single or multiple point mutation were introduced at the Asn-153 and Asn-67 glycosylation sites, respectively, on the E protein ofDENV-2 strains NGC and PUO-218, using two infectious cDNA clones. DENV -2 strain, NGC, is a laboratory-adapted virus, while strain PUO-218 is a low-passage natural isolate from Toxorhynchites splendens mosquitoes. ... I also show that removal of both glycans from the DENV-2 E protein prevents the recovery of viable virus with a stable mutant genotype (Chapters 3 and 5). Nevertheless, given the importance of strain origin and type of substitution used for deletion of the carbohydrate acceptor sites that I have demonstrated in this thesis, it is likely that the engineering of a viable DENV variant lacking both E protein glycans is feasible

Broadly tunable (440-670 nm) solid-state organic laser with disposable capsules

An innovative concept of thin-film organic solid-state laser is proposed, with diffraction-limited output and a broad tuning range covering the visible spectrum under UV optical pumping. The laser beam is tunable over 230 nm, from 440 to 670 nm, with a 3 nm full width at half maximum typical spectral width. The structure consists of a compact fixed bulk optical cavity, a polymeric intracavity etalon for wavelength tuning, as well as five different disposable glass slides coated with a dye-doped polymer film, forming a very simple and low-cost gain medium. The use of interchangeable/disposable "gain capsules" is an alternative solution to photodegradation issues, since gain chips can be replaced without realignment of the cavity. The laser lifetime of a single chip in ambient conditions and without encapsulation was extrapolated to be around 107 pulses at a microjoule energy-per-pulse level

Fish fights over fish rights: Conflicts arising from re-allocation of fishing lots: perceptions from community fisheries in Cambodia

Disputes, Aquaculture, Cambodia,

Étude du spectre d'électrons de conversion de faible énergie émis par le Francium 221 (225Ac →α 221Fr)

Le spectre d'électrons de conversion émis par 221Fr a été étudié par un spectromètre βπ √2. Les multipolarités des transitions intenses ont été déterminées. Un désaccord existe entre Iγ et I e- pour les rayonnements de 73,7 et 99,6 keV, ce qui a conduit à l'hypothèse d'un niveau double à 99,6 keV

Étude des rayonnements gamma accompagnant la désintégration alpha du protactinium 231 (231Pa α → 227 Ac)

Les rayonnements γ accompagnant la désintégration 231Pa α → 227Ac ont été étudiés par spectrométrie γ de grande résolution et par coïncidences α-γ bidimensionnelles avec un calculateur IBM 360-50. Un schéma de niveaux de 227Ac est construit à partir des nouveaux résultats expérimentaux