Issues in visual support to real-time space system simulation solved in the Systems Engineering Simulator

The Systems Engineering Simulator has addressed the major issues in providing visual data to its real-time man-in-the-loop simulations. Out-the-window views and CCTV views are provided by three scene systems to give the astronauts their real-world views. To expand the window coverage for the Space Station Freedom workstation a rotating optics system is used to provide the widest field of view possible. To provide video signals to as many viewpoints as possible, windows and CCTVs, with a limited amount of hardware, a video distribution system has been developed to time-share the video channels among viewpoints at the selection of the simulation users. These solutions have provided the visual simulation facility for real-time man-in-the-loop simulations for the NASA space program

Molecular emission near metal interfaces: the polaritonic regime

The strong coupling of a dense layer of molecular excitons with surface-plasmon modes in a metal gives rise to polaritons (hybrid light-matter states) called plexcitons. Surface plasmons cannot directly emit into (or be excited by) free-space photons due to the fact that energy and momentum conservation cannot be simultaneously satisfied in photoluminescence. Most plexcitons are also formally non-emissive, even though they can radiate via molecules upon localization due to disorder and decoherence. However, a fraction of them are bright even in the presence of such deleterious processes. In this letter, we theoretically discuss the superradiant emission properties of these bright plexcitons, which belong to the upper energy branch and reveal huge photoluminescence enhancements compared to bare excitons. Our study generalizes the well-known problem of molecular emission next to a metal interface to collective molecular states and provides new design principles for the control of photophysical properties of molecular aggregates using polaritonic strategies.Comment: Replaced previous version, noticing that van Hove anomalies are only observed in the direct and reflected contributions of photoluminescence, but they cancel out when added up in the total photoluminescence. The correct phenomenology is that enhancements of photoluminescence are still huge (not infinite) and are near (not exactly at) the critical poin

The use of interleaving for reducing radio loss in convolutionally coded systems

The use of interleaving after convolutional coding and deinterleaving before Viterbi decoding is proposed. This effectively reduces radio loss at low-loop Signal to Noise Ratios (SNRs) by several decibels and at high-loop SNRs by a few tenths of a decibel. Performance of the coded system can further be enhanced if the modulation index is optimized for this system. This will correspond to a reduction of bit SNR at a certain bit error rate for the overall system. The introduction of interleaving/deinterleaving into communication systems designed for future deep space missions does not substantially complicate their hardware design or increase their system cost

Unsolved problems in the lowermost mantle

Many characteristics of D '' layer may be attributed to the recently discovered MgSiO3 post-perovskite phase without chemical heterogeneities. They include a sharp discontinuity at the top of D '', regional variation in seismic anisotropy, and a steep Clapeyron slope. However, some features remain unexplained. The seismically inferred velocity jump is too large in comparison to first principles calculations, and the sharpness of the discontinuity may require a chemical boundary. Chemical heterogeneity may play an important role in addition to the phase transformation from perovskite to post-perovskite. Phase transformation and chemical heterogeneity and the attendant changes in physical properties, such as rheology and thermal conductivity, are likely to play competing roles in defining the dynamical stability of the D '' layer. Revealing the relative roles between phase transition and chemical anomalies is an outstanding challenge in the study of the role of D '' in thermal-chemical evolution of the Earth

Effect of aging on prose recall

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A Guide to Publication in Educational Technology

This guide provides journal information to over 40 journals that are appropriate for the publication of articles in educational technology. Also, it discusses the process of planning and writing a journal article, submitting to journals, the peer reviewing process, and steps toward publishing in academic journals within the field of educational technology. Furthermore, the guide provides tips to getting published and offers helpful suggestions

Phase measurements with weak reference pulses

Quantum state discrimination for two coherent states with opposite phases as measured relative to a reference pulse is analyzed as functions of the intensities of both the signal states and of the reference pulse. This problem is relevant for Quantum Key Distribution with phase encoding. We consider both the optimum measurements and simple measurements that require only beamsplitters and photodetectors.Comment: 5 pages, 5 figures. I apologize for this boring pape

The Trinidad and Tobago/Venezuela Fishing Agreement

The twin-island Republic of Trinidad and Tobago is situated adjacent to the Republic Of Venezuela such that at one point Trinidad is merely seven miles off the northeast coast of Venezuela. Fishing activities of nationals of each country in the waters of the other are therefore common and often lead to conflict. In an attempt to solve the fishing problem a fishing agreement was negotiated. It came into force in 1978 and expired in 1984 whereupon negotiations commenced once more in an attempt to achieve new accord. The fishing industries of both countries and the conflicts which led to the agreement are described. Fishing activities by nationals of each state in the waters of the other are detailed and values of these catches are estimate and compared. Conflicts and problems related to treaty implementation are discussed and proposals for a new agreement suggested. Indications are that Venezuela was the greater beneficiary of the agreement in terms of quality and value of catch; number of boats fishing and number of men employed; diversity of species landed. Four proposals which could lead to a more equitable agreement than the last are suggested. These proposals include options outside of the terms of the last agreement but which, if implemented, would be of benefit to both parties while simultaneously establishing closer relations over a wider sphere of activities