WorldWideScience

Sample records for proximity-1 space link

  1. Analysis of Proximity-1 Space Link Interleaved Time Synchronization (PITS) Protocol

    Science.gov (United States)

    Woo, Simon S.

    2011-01-01

    To synchronize clocks between spacecraft in proximity, the Proximity-1 Space Link Interleaved Time Synchronization (PITS) Protocol has been proposed. PITS is based on the NTP Interleaved On-Wire Protocol and is capable of being adapted and integrated into CCSDS Proximity-1 Space Link Protocol with minimal modifications. In this work, we will discuss the correctness and liveness of PITS. Further, we analyze and evaluate the performance of time synchronization latency with various channel error rates in different PITS operational modes.

  2. Software Modules for the Proximity-1 Space Link Interleaved Time Synchronization (PITS) Protocol

    Science.gov (United States)

    Woo, Simon S.; Veregge, John R.; Gao, Jay L.; Clare, Loren P.; Mills, David

    2012-01-01

    The Proximity-1 Space Link Interleaved Time Synchronization (PITS) protocol provides time distribution and synchronization services for space systems. A software prototype implementation of the PITS algorithm has been developed that also provides the test harness to evaluate the key functionalities of PITS with simulated data source and sink. PITS integrates time synchronization functionality into the link layer of the CCSDS Proximity-1 Space Link Protocol. The software prototype implements the network packet format, data structures, and transmit- and receive-timestamp function for a time server and a client. The software also simulates the transmit and receive-time stamp exchanges via UDP (User Datagram Protocol) socket between a time server and a time client, and produces relative time offsets and delay estimates.

  3. The CCSDS Next Generation Space Data Link Protocol (NGSLP)

    Science.gov (United States)

    Kazz, Greg J.; Greenberg, Edward

    2014-01-01

    The CCSDS space link protocols i.e., Telemetry (TM), Telecommand (TC), Advanced Orbiting Systems (AOS) were developed in the early growth period of the space program. They were designed to meet the needs of the early missions, be compatible with the available technology and focused on the specific link environments. Digital technology was in its infancy and spacecraft power and mass issues enforced severe constraints on flight implementations. Therefore the Telecommand protocol was designed around a simple Bose, Hocquenghem, Chaudhuri (BCH) code that provided little coding gain and limited error detection but was relatively simple to decode on board. The infusion of the concatenated Convolutional and Reed-Solomon codes5 for telemetry was a major milestone and transformed telemetry applications by providing them the ability to more efficiently utilize the telemetry link and its ability to deliver user data. The ability to significantly lower the error rates on the telemetry links enabled the use of packet telemetry and data compression. The infusion of the high performance codes for telemetry was enabled by the advent of digital processing, but it was limited to earth based systems supporting telemetry. The latest CCSDS space link protocol, Proximity-1 was developed in early 2000 to meet the needs of short-range, bi-directional, fixed or mobile radio links characterized by short time delays, moderate but not weak signals, and short independent sessions. Proximity-1 has been successfully deployed on both NASA and ESA missions at Mars and is planned to be utilized by all Mars missions in development. A new age has arisen, one that now provides the means to perform advanced digital processing in spacecraft systems enabling the use of improved transponders, digital correlators, and high performance forward error correcting codes for all communications links. Flight transponders utilizing digital technology have emerged and can efficiently provide the means to make the

  4. Link Analysis for Space Communication Links Using ARQ Protocol

    Science.gov (United States)

    Cheung, Kar-Ming; Lau, Chi-Wung; Lee, Charles

    2014-01-01

    In space communications, standard link analysis assumes that messages are sent once. For a communication link that uses an error-correction coding scheme, bit-error-rate (BER) or frame-error-rate (FER), and link margins are common metrics that characterize the quality of a link, and they are used to determine the supportable data rate. With the advent of Automatic Repeat-reQuest (ARQ) protocols, when messages are corrupted during transmission, they can be resent multiple times automatically until they are correctly received and acknowledged. The concept of BER, FER, and link margin cannot be directly applied, and the link analysis approach for ARQ links needs to be re-examined.

  5. Deep Space Optical Link ARQ Performance Analysis

    Science.gov (United States)

    Clare, Loren; Miles, Gregory

    2016-01-01

    Substantial advancements have been made toward the use of optical communications for deep space exploration missions, promising a much higher volume of data to be communicated in comparison with present -day Radio Frequency (RF) based systems. One or more ground-based optical terminals are assumed to communicate with the spacecraft. Both short-term and long-term link outages will arise due to weather at the ground station(s), space platform pointing stability, and other effects. To mitigate these outages, an Automatic Repeat Query (ARQ) retransmission method is assumed, together with a reliable back channel for acknowledgement traffic. Specifically, the Licklider Transmission Protocol (LTP) is used, which is a component of the Disruption-Tolerant Networking (DTN) protocol suite that is well suited for high bandwidth-delay product links subject to disruptions. We provide an analysis of envisioned deep space mission scenarios and quantify buffering, latency and throughput performance, using a simulation in which long-term weather effects are modeled with a Gilbert -Elliot Markov chain, short-term outages occur as a Bernoulli process, and scheduled outages arising from geometric visibility or operational constraints are represented. We find that both short- and long-term effects impact throughput, but long-term weather effects dominate buffer sizing and overflow losses as well as latency performance.

  6. The XML approach to implementing space link extension service management

    Science.gov (United States)

    Tai, W.; Welz, G. A.; Theis, G.; Yamada, T.

    2001-01-01

    A feasibility study has been conducted at JPL, ESOC, and ISAS to assess the possible applications of the eXtensible Mark-up Language (XML) capabilities to the implementation of the CCSDS Space Link Extension (SLE) Service Management function.

  7. A 400 Gbps/100 m free-space optical link

    Science.gov (United States)

    Lin, Chun-Yu; Lu, Hai-Han; Ho, Chun-Ming; Cheng, Ming-Te; Huang, Sheng-Jhe; Wang, Yun-Chieh; Chi, Jing-Kai

    2017-02-01

    A 400 Gbps/100 m free-space optical (FSO) link with dense-wavelength-division-multiplexing (DWDM)/space-division-multiplexing (SDM) techniques and a doublet lens scheme is proposed. To the best of our knowledge, this is the first time that a link adopting DWDM and SDM techniques and a doublet lens scheme has demonstrated a 400 Gbps/100 m FSO link. The experimental results show that the free-space transmission rate is significantly enhanced by the DWDM and SDM techniques, and the free-space transmission distance is greatly increased by the doublet lens scheme. A 16-channel FSO link with a total transmission rate of 400 Gbps (25 Gbps/λ  ×  16 λ  =  400 Gbps) over a 100 m free-space link is successfully demonstrated. Such a 400 Gbps/100 m DWDM/SDM FSO link provides the advantages of optical wireless communications for high transmission rates and long transmission distances, which is very useful for high-speed and long-haul light-based WiFi (LiFi) applications.

  8. Linking of uniform random polygons in confined spaces

    Energy Technology Data Exchange (ETDEWEB)

    Arsuaga, J [Department of Mathematics, San Francisco State University, 1600 Holloway Ave, San Francisco, CA 94132 (United States); Blackstone, T [Department of Computer Science, San Francisco State University, 1600 Holloway Ave, San Francisco, CA 94132 (United States); Diao, Y [Department of Mathematics and Statistics University of North Carolina, Charlotte 9201, University City Blvd Charlotte, NC 28223 (United States); Karadayi, E [Department of Mathematics, University of South Florida, 4202 E Fowler Avenue Tampa, FL 33620 (United States); Saito, M [Department of Mathematics, University of South Florida, 4202 E Fowler Avenue Tampa, FL 33620 (United States)

    2007-03-02

    In this paper, we study the topological entanglement of uniform random polygons in a confined space. We derive the formula for the mean squared linking number of such polygons. For a fixed simple closed curve in the confined space, we rigorously show that the linking probability between this curve and a uniform random polygon of n vertices is at least 1-O(1/{radical}n). Our numerical study also indicates that the linking probability between two uniform random polygons (in a confined space), of m and n vertices respectively, is bounded below by 1-O(1/{radical}(mn)). In particular, the linking probability between two uniform random polygons, both of n vertices, is bounded below by 1-O(1/n)

  9. Linked Data Evolving the Web into a Global Data Space

    CERN Document Server

    Heath, Tom

    2011-01-01

    The World Wide Web has enabled the creation of a global information space comprising linked documents. As the Web becomes ever more enmeshed with our daily lives, there is a growing desire for direct access to raw data not currently available on the Web or bound up in hypertext documents. Linked Data provides a publishing paradigm in which not only documents, but also data, can be a first class citizen of the Web, thereby enabling the extension of the Web with a global data space based on open standards - the Web of Data. In this Synthesis lecture we provide readers with a detailed technical i

  10. Linking African Researchers with Adaptation Policy Spaces | CRDI ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Linking African Researchers with Adaptation Policy Spaces. Poor understanding of policy processes tends to reduce the value of research results and the ability of researchers to influence policy. One of the main goals of IDRC's Climate Change Adaptation in Africa (CCAA) program is to build the capacity of researchers to ...

  11. a Web Service Approach for Linking Sensors and Cellular Spaces

    Science.gov (United States)

    Isikdag, U.

    2013-09-01

    More and more devices are starting to be connected to the Internet. In the future the Internet will not only be a communication medium for people, it will in fact be a communication environment for devices. The connected devices which are also referred as Things will have an ability to interact with other devices over the Internet, i.) provide information in interoperable form and ii.) consume /utilize such information with the help of sensors embedded in them. This overall concept is known as Internet-of- Things (IoT). This requires new approaches to be investigated for system architectures to establish relations between spaces and sensors. The research presented in this paper elaborates on an architecture developed with this aim, i.e. linking spaces and sensors using a RESTful approach. The objective is making spaces aware of (sensor-embedded) devices, and making devices aware of spaces in a loosely coupled way (i.e. a state/usage/function change in the spaces would not have effect on sensors, similarly a location/state/usage/function change in sensors would not have any effect on spaces). The proposed architecture also enables the automatic assignment of sensors to spaces depending on space geometry and sensor location.

  12. Unsupervised Action Classification Using Space-Time Link Analysis

    Directory of Open Access Journals (Sweden)

    Feris Rogerio

    2010-01-01

    Full Text Available We address the problem of unsupervised discovery of action classes in video data. Different from all existing methods thus far proposed for this task, we present a space-time link analysis approach which consistently matches or exceeds the performance of traditional unsupervised action categorization methods in various datasets. Our method is inspired by the recent success of link analysis techniques in the image domain. By applying these techniques in the space-time domain, we are able to naturally take into account the spatiotemporal relationships between the video features, while leveraging the power of graph matching for action classification. We present a comprehensive set of experiments demonstrating that our approach is capable of handling cluttered backgrounds, activities with subtle movements, and video data from moving cameras. State-of-the-art results are reported on standard datasets. We also demonstrate our method in a compelling surveillance application with the goal of avoiding fraud in retail stores.

  13. Unsupervised action classification using space-time link analysis

    DEFF Research Database (Denmark)

    Liu, Haowei; Feris, Rogerio; Krüger, Volker

    2010-01-01

    In this paper we address the problem of unsupervised discovery of action classes in video data. Different from all existing methods thus far proposed for this task, we present a space-time link analysis approach which matches the performance of traditional unsupervised action categorization methods...... in a standard dataset. Our method is inspired by the recent success of link analysis techniques in the image domain. By applying these techniques in the space-time domain, we are able to naturally take into account the spatio-temporal relationships between the video features, while leveraging the power of graph...... matching for action classification. We present an experiment to demonstrate that our approach is capable of handling cluttered backgrounds, activities with subtle movements, and video data from moving cameras....

  14. Linking the space shuttle and space stations early docking technologies from concept to implementation

    CERN Document Server

    Shayler, David J

    2017-01-01

    How could the newly authorized space shuttle help in the U.S. quest to build a large research station in Earth orbit? As a means of transporting goods, the shuttle could help supply the parts to the station. But how would the two entitles be physically linked? Docking technologies had to constantly evolve as the designs of the early space stations changed. It was hoped the shuttle would make missions to the Russian Salyut and American Skylab stations, but these were postponed until the Mir station became available, while plans for getting a new U. S. space station underway were stalled. In Linking the Space Shuttle and Space Stations, the author delves into the rich history of the Space Shuttle and its connection to these early space stations, culminating in the nine missions to dock the shuttle to Mir. By 1998, after nearly three decades of planning and operations, shuttle missions to Mir had resulted in: • A proven system to link up the space shuttle to a space station • Equipment and hands-on experienc...

  15. Ultra-stable optical links for space and ground applications

    Science.gov (United States)

    Narbonneau, F.; Lours, M.; Daussy, C.; Lopez, O.; Clairon, A.; Santarelli, G.

    2017-11-01

    We have demonstrated the feasibility of a free-space ultra-stable optical link on a 3 meters test bench, operating at 100 MHz. With this type of link, it is possible to transfer a 100 MHz signal with a relative frequency stability of a few 10-14 at one second integration time, 10-16 at one day and a phase stability of a few picoseconds per day in presence of moderate mechanical vibrations and thermal fluctuations. The comparisons of modern clocks of distant (<100 km) Time and Frequency laboratories have a strong scientific interest. In this context we study a low noise frequency distribution via optical fibres. Some preliminary tests have been realized and the results are encouraging. We expect to transfer ultra stable oscillators with a relative frequency stability of a few 10-14 at one second integration time, 10-16 at one day.

  16. Space Weather: Linking Stellar Explosions to the Human Endeavor

    Science.gov (United States)

    Knipp, Delores

    2017-06-01

    Arguably humans have flourished as a result of stellar explosions; we are, after all, stardust. Nonetheless, rapid technology advances of the last 200 years sometimes put society and individuals on a collision course with the natural variability of stellar and solar atmospheres. Human space exploration, routine satellite navigation system applications, aviation safety, and electric power grids are examples of such vulnerable endeavors. In this presentation I will outline how global society relies on ‘normal’ solar and stellar emissions, yet becomes susceptible to extremes of these emissions. The imprints of these astronomical-terrestrial interactions abound. In particular, I will highlight ways in which stellar/solar bursts link with our space-atmosphere-interaction region, producing multi-year patterns in cosmic ray detection, gorgeous aurora, and deep concern for good order and function of global community.

  17. Space Resources Development: The Link Between Human Exploration and the Long-Term Commercialization of Space

    Science.gov (United States)

    Sanders, Gerald B.

    2000-01-01

    In a letter to the NASA Administrator, Dan Goldin, in January of 1999, the Office of Management and Budget (OMB) stated the following . OMB recommends that NASA consider commercialization in a broader context than the more focused efforts to date on space station and space shuttle commercialization. We suggest that NASA examine architectures that take advantage of a potentially robust future commercial infrastructure that could dramatically lower the cost of future human exploration." In response to this letter, the NASA Human Exploration and Development of Space (HEDS) Enterprise launched the BEDS Technology & Commercialization Initiative (HTCI) to link technology and system development for human exploration with the commercial development of space to emphasize the "D" (Development) in BEDS. The development of technologies and capabilities to utilize space resources is the first of six primary focus areas in this program. It is clear that Space Resources Development (SRD) is key for both long-term human exploration of our solar system and to the long-term commercialization of space since: a) it provides the technologies, products, and raw materials to support efficient space transportation and in-space construction and manufacturing, and b) it provides the capabilities and infrastructure to allow outpost growth, self-sufficiency, and commercial space service and utility industry activities.

  18. Free-space optical wireless links with topology control

    Science.gov (United States)

    Milner, Stuart D.; Ho, Tzung-Hsien; Smolyaninov, Igor I.; Trisno, Sugianto; Davis, Christopher C.

    2002-12-01

    The worldwide demand for broadband communications is being met in many places through the use of installed single-mode fiber networks. However, there is still a significant 'first-mile' problem, which seriously limits the availability of broadband Internet access. Free-space optical wireless communication has emerged as a technique of choice for bridging gaps in the existing high data rate communication networks, and as a backbone for rapidly deployable mobile wireless communication infrastructure. Because free space laser communication links can be easily and rapidly redirected, optical wireless networks can be autonomously reconfigured in a multiple-connected topology to provide improved network performance. In this paper we describe research designed to improve the performance of such networks. Using topology control algorithms, we have demonstrated that multiply-connected, rapidly reconfigurable optical wireless networks can provide robust performance, and a high quality of service at high data rates (up to and beyond 1 Gbps). These systems are also very cost-effective. We have designed and tested on the University of Maryland campus a prototype four-node optical wireless network, where each node could be connected to the others via steerable optical wireless links. The design and performance of this network and the topology control is discussed.

  19. Information Theoretical Limits of Free-Space Optical Links

    KAUST Repository

    Ansari, Imran Shafique

    2016-08-25

    Generalized fading has been an imminent part and parcel of wireless communications. It not only characterizes the wireless channel appropriately but also allows its utilization for further performance analysis of various types of wireless communication systems. Under the umbrella of generalized fading channels, a unified ergodic capacity analysis of a free-space optical (FSO) link under both types of detection techniques (i.e., intensity modulation/direct detection (IM/DD) as well as heterodyne detection) over generalized atmospheric turbulence channels that account for generalized pointing errors is presented. Specifically, unified exact closed-form expressions for the moments of the end-to-end signal-to-noise ratio (SNR) of a single link FSO transmission system are presented. Subsequently, capitalizing on these unified statistics, unified exact closed-form expressions for ergodic capacity performance metric of FSO link transmission systems is offered. Additionally, for scenarios wherein the exact closed-form solution is not possible to obtain, some asymptotic results are derived in the high SNR regime. All the presented results are verified via computer-based Monte-Carlo simulations.

  20. Multi-User Space Link Extension (SLE) System

    Science.gov (United States)

    Perkins, Toby

    2013-01-01

    The Multi-User Space (MUS) Link Extension system, a software and data system, provides Space Link Extension (SLE) users with three space data transfer services in timely, complete, and offline modes as applicable according to standards defined by the Consultative Committee for Space Data Systems (CCSDS). MUS radically reduces the schedule, cost, and risk of implementing a new SLE user system, minimizes operating costs with a lights-out approach to SLE, and is designed to require no sustaining engineering expense during its lifetime unless changes in the CCSDS SLE standards, combined with new provider implementations, force changes. No software modification to MUS needs to be made to support a new mission. Any systems engineer with Linux experience can begin testing SLE user service instances with MUS starting from a personal computer (PC) within five days. For flight operators, MUS provides a familiar-looking Web page for entering SLE configuration data received from SLE. Operators can also use the Web page to back up a space mission's entire set of up to approximately 500 SLE service instances in less than five seconds, or to restore or transfer from another system the same amount of data from a MUS backup file in about the same amount of time. Missions operate each MUS SLE service instance independently by sending it MUS directives, which are legible, plain ASCII strings. MUS directives are usually (but not necessarily) sent through a TCP-IP (Transmission Control Protocol Internet Protocol) socket from a MOC (Mission Operations Center) or POCC (Payload Operations Control Center) system, under scripted control, during "lights-out" spacecraft operation. MUS permits the flight operations team to configure independently each of its data interfaces; not only commands and telemetry, but also MUS status messages to the MOC. Interfaces can use single- or multiple-client TCP/IP server sockets, TCP/IP client sockets, temporary disk files, the system log, or standard in

  1. A Mobile Communications Space Link Between the Space Shuttle Orbiter and the Advanced Communications Technology Satellite

    Science.gov (United States)

    Fink, Patrick; Arndt, G. D.; Bondyopadhyay, P.; Shaw, Roland

    1994-01-01

    A communications experiment is described as a link between the Space Shuttle Orbiter (SSO) and the Advanced Communications Technology Satellite (ACTS). Breadboarding for this experiment has led to two items with potential for commercial application: a 1-Watt Ka-band amplifier and a Ka-band, circularly polarized microstrip antenna. Results of the hybrid Ka-band amplifier show gain at 30 dB and a saturated output power of 28.5 dBm. A second version comprised of MMIC amplifiers is discussed. Test results of the microstrip antenna subarray show a gain of approximately 13 dB and excellent circular polarization.

  2. Data link relay design. [space probe with entry at Uranus

    Science.gov (United States)

    Parsons, P.

    1974-01-01

    The data link for the Ames baseline probe as applied to the MJU spacecraft specifically with an entry at Uranus is analyzed. A frequency analysis, a trajectory analysis, and a discussion of the effects on the spacecraft design by the data link are presented. The possibilities of a two-way link are considered.

  3. An index formula for the self-linking number of a space curve

    DEFF Research Database (Denmark)

    Røgen, Peter

    2008-01-01

    Given an embedded closed space curve with non-vanishing curvature, its self-linking number is defined as the linking number between the original curve and a curve pushed slightly off in the direction of its principal normals. We present an index formula for the self-linking number in terms of the...

  4. Indoor Abstract Spaces : Linking IndoorGML and LADM

    NARCIS (Netherlands)

    Zlatanova, S.; Li, Ki Joune; Lemmen, Christiaan; van Oosterom, P.J.M.; van Oosterom, Peter; Dimopoulou, Efi; Fendel, Elfriede M.

    2016-01-01

    In this paper we investigate the possible synergy between two different but related standards: OGC’s IndoorGML and ISO TC211’s LADM. Both (can) deal with 3D spaces with properties, constraints and associations attached and both can operate with abstract notations of space. But there are also

  5. Indoor Abstract Spaces: Linking IndoorGML and LADM

    OpenAIRE

    S. Zlatanova; Li, Ki-Joune; Lemmen, Christiaan; van Oosterom, P.J.M.; Oosterom, Peter van; Dimopoulou, Efi; Fendel, Elfriede M.

    2016-01-01

    In this paper we investigate the possible synergy between two different but related standards: OGC’s IndoorGML and ISO TC211’s LADM. Both (can) deal with 3D spaces with properties, constraints and associations attached and both can operate with abstract notations of space. But there are also differences, e.g. LADM is a conceptual model, while IndoorGML is also an actual XML schema (technical model), which can be used directly for data exchange and storage. Also, the scope is different; e.g. I...

  6. Linking African Researchers with Adaptation Policy Spaces | IDRC ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... processes in different countries and identify policy spaces; use this knowledge to build policy engagement tools and strategy; develop an analytical framework for investigating climate change adaptation policy processes in Africa; and mentor relationships between participatory action researchers and academic partners.

  7. Optical ground station site diversity for Deep Space Optical Communications the Mars Telecom Orbiter optical link

    Science.gov (United States)

    Wilson, K.; Parvin, B.; Fugate, R.; Kervin, P.; Zingales, S.

    2003-01-01

    Future NASA deep space missions will fly advanced high resolution imaging instruments that will require high bandwidth links to return the huge data volumes generated by these instruments. Optical communications is a key technology for returning these large data volumes from deep space probes. Yet to cost effectively realize the high bandwidth potential of the optical link will require deployment of ground receivers in diverse locations to provide high link availability. A recent analysis of GOES weather satellite data showed that a network of ground stations located in Hawaii and the Southwest continental US can provide an average of 90% availability for the deep space optical link. JPL and AFRL are exploring the use of large telescopes in Hawaii, California, and Albuquerque to support the Mars Telesat laser communications demonstration. Designed to demonstrate multi-Mbps communications from Mars, the mission will investigate key operational strategies of future deep space optical communications network.

  8. Impact of a half-space interface on the wireless link between tiny sensor nodes

    Science.gov (United States)

    Penkin, Dmitriy; Janssen, Gerard; Yarovoy, Alexander

    2014-09-01

    The power budget of a wireless link between two electrically small sensor nodes located close to an interface between two media is studied. The model includes both the propagation channel losses and input impedance of the radio frequency antennas. It is shown that a highly inductive half-space significantly enhances the received power due to the contribution of the surface wave while not resulting in considerable mismatch losses between the antennas and electronics. Hence, such a half-space improves the link gain, which may compensate the limited energy available for transmission from electrically and physically small nodes.

  9. Simulation of the influence of atmospheric conditions on low-cost optical free space link

    Science.gov (United States)

    Latal, Jan; Koudelka, Petr; Vitasek, Jan; Siska, Petr; Skapa, Jan; Liner, Andrej; Papes, Martin; Vasinek, Vladimir

    2012-06-01

    The team of authors was concerned in the development and construction of low-cost free space optical link and simulations of the influence of atmospheric conditions on this link. The article contains description of electronic design and attention is also dedicated to simulations of atmospheric conditions. Gradually, the most frequently occurring atmospheric conditions and their impact on the available bit rates were tested. An integral part of the article is calculation of the energy balance of the whole link. At the end are shown images of the measured eye diagrams and samples of measured distribution of optical power using a digital camera and its processing in MATLAB.

  10. How Strongly Linked Are Mental Time and Space along the Left-Right Axis?

    Science.gov (United States)

    Eikmeier, Verena; Alex-Ruf, Simone; Maienborn, Claudia; Ulrich, Rolf

    2015-01-01

    Different lines of research suggest that our mental representations of time and space are linked, though the strength of this linkage has only recently been addressed for the front-back mental timeline (Eikmeier, Schröter, Maienborn, Alex-Ruf, & Ulrich, 2013). The present study extends this investigation to the left-right mental timeline. In…

  11. Proposed parameters of specific rain attenuation prediction for Free Space Optics link operating in tropical region

    Science.gov (United States)

    Suriza, A. Z.; Md Rafiqul, Islam; Wajdi, A. K.; Naji, A. W.

    2013-03-01

    As the demand for higher and unlimited bandwidth for communication channel is increased, Free Space Optics (FSO) is a good alternative solution. As it is protocol transparent, easy to install, cost effective and have capabilities like fiber optics, its demand rises very fast. Weather condition, however is the limiting factor for FSO link. In the temperate region the major blockage for FSO link feasibility is fog. In the tropical region high rainfall rate is expected to be the major drawback of FSO link availability. Rain attenuation is the most significant to influence FSO link availability in tropical region. As for now the available k and α values are developed using data from temperate regions. Therefore, the objective of this paper is to propose new parameters for specific rain attenuation prediction model that represents tropical weather condition. The proposed values are derived from data measured in Malaysia and using methods recommended by ITU-R.

  12. Some effects of Space Weather in a 4GHz communication satellite link over the Brazilian Region

    Science.gov (United States)

    Soares, A.

    This work concerns a study of some effects of Space Weather in a C-band Satellite Link between Rio de Janeiro (22o57'S, 43o11'W) and Vitoria (20o10SS, 40o10SW), in the SouthEast of Brazil, from October 2000 to nowadays. An automatic acquisition system was developed to register the spectrum of the used frequencies and, since January 2002, this system has also registered the data corruption over a known information embedded in the link. As a result of this monitoring now we can know some useful things about the interference caused by geophisical phenomena like Plasma Bubbles.

  13. MEMS tracking mirror system for a bidirectional free-space optical link.

    Science.gov (United States)

    Jeon, Sungho; Toshiyoshi, Hiroshi

    2017-08-20

    We report on a bidirectional free-space optical system that is capable of automatic connection and tracking of an optical link between two nodes. A piezoelectric micro-electro-mechanical systems (MEMS) optical scanner is used to steer a laser beam of two wavelengths superposed to visually present a communication zone, to search for the position of the remote node by means of the retro-reflector optics, and to transmit the data between the nodes. A feedback system is developed to control the MEMS scanner to dynamically establish the optical link within a 10-ms transition time and to keep track of the moving node.

  14. Probabilistic Model for Free-Space Optical Links Under Continental Fog Conditions

    OpenAIRE

    Marzuki; Faisal, M.; Sheikh Muhammad, S.; M. S. Awan; Khan, M S; F. Nadeem; Leitgeb, E.

    2010-01-01

    The error characteristics of a free-space optical (FSO) channel are significantly different from the fiber based optical links and thus require a deep physical understanding of the propagation channel. In particular different fog conditions greatly influence the optical transmissions and thus a channel model is required to estimate the detrimental fog effects. In this paper we shall present the probabilistic model for radiation fog from the measured data over a 80 m FSO link installed at Graz, A...

  15. Adaptive Bit Rate Video Streaming Through an RF/Free Space Optical Laser Link

    Directory of Open Access Journals (Sweden)

    A. Akbulut

    2010-06-01

    Full Text Available This paper presents a channel-adaptive video streaming scheme which adjusts video bit rate according to channel conditions and transmits video through a hybrid RF/free space optical (FSO laser communication system. The design criteria of the FSO link for video transmission to 2.9 km distance have been given and adaptive bit rate video streaming according to the varying channel state over this link has been studied. It has been shown that the proposed structure is suitable for uninterrupted transmission of videos over the hybrid wireless network with reduced packet delays and losses even when the received power is decreased due to weather conditions.

  16. Free-space optical communication link using perfect vortex beams carrying orbital angular momentum (OAM)

    Science.gov (United States)

    Zhu, Fuquan; Huang, Sujuan; Shao, Wei; Zhang, Jie; Chen, Musheng; Zhang, Weibing; Zeng, Junzhang

    2017-08-01

    We experimentally demonstrate a free-space optical communication link using perfect vortex beams. Perfect vortex beams with different topological charges are generated using a phase-modulation-type spatial light modulator (SLM) loaded with novel phase holograms based on the Bessel function. With the help of a microscope objective and simple lens, perfect vortex beams are transmitted effectively for a certain distance. After completing the demodulation of perfect vortex beams carrying OFDM 16-QAM signals and a series of offline processing on the Gaussian bright spot demodulated from the perfect vortex beams, we also achieve a communication link. The constellations and mean bit error rates (BER) of subcarriers are shown.

  17. DC link current simulation of voltage source inverter with random space vector pulse width modulation

    Directory of Open Access Journals (Sweden)

    Chen Guoqiang

    2016-01-01

    Full Text Available Aiming at analysis complexity, a simulation model is built and presented to analyze and demonstrate the characteristics of the direct current (DC link current of the three-phase two-level inverter with the random space vector pulse width modulation (SVPWM strategy. The developing procedure and key subsystems of the simulation model are given in detail. Several experiments are done using the simulation model. The results verify the efficiency and convenience of the simulation model and show that the random SVPWM scheme, especially the random switching frequency scheme, can efficiently suppress the harmonic peaks of the DC link current.

  18. The computer-communication link for the innovative use of Space Station

    Science.gov (United States)

    Carroll, C. C.

    1984-01-01

    The potential capability of the computer-communications system link of space station is related to innovative utilization for industrial applications. Conceptual computer network architectures are presented and their respective accommodation of innovative industrial projects are discussed. To achieve maximum system availability for industrialization is a possible design goal, which would place the industrial community in an interactive mode with facilities in space. A worthy design goal would be to minimize the computer-communication management function and thereby optimize the system availability for industrial users. Quasi-autonomous modes and subnetworks are key design issues, since they would be the system elements directly effecting the system performance for industrial use.

  19. Distribution of high-dimensional entanglement via an intra-city free-space link

    Science.gov (United States)

    Steinlechner, Fabian; Ecker, Sebastian; Fink, Matthias; Liu, Bo; Bavaresco, Jessica; Huber, Marcus; Scheidl, Thomas; Ursin, Rupert

    2017-07-01

    Quantum entanglement is a fundamental resource in quantum information processing and its distribution between distant parties is a key challenge in quantum communications. Increasing the dimensionality of entanglement has been shown to improve robustness and channel capacities in secure quantum communications. Here we report on the distribution of genuine high-dimensional entanglement via a 1.2-km-long free-space link across Vienna. We exploit hyperentanglement, that is, simultaneous entanglement in polarization and energy-time bases, to encode quantum information, and observe high-visibility interference for successive correlation measurements in each degree of freedom. These visibilities impose lower bounds on entanglement in each subspace individually and certify four-dimensional entanglement for the hyperentangled system. The high-fidelity transmission of high-dimensional entanglement under real-world atmospheric link conditions represents an important step towards long-distance quantum communications with more complex quantum systems and the implementation of advanced quantum experiments with satellite links.

  20. Distribution of high-dimensional entanglement via an intra-city free-space link.

    Science.gov (United States)

    Steinlechner, Fabian; Ecker, Sebastian; Fink, Matthias; Liu, Bo; Bavaresco, Jessica; Huber, Marcus; Scheidl, Thomas; Ursin, Rupert

    2017-07-24

    Quantum entanglement is a fundamental resource in quantum information processing and its distribution between distant parties is a key challenge in quantum communications. Increasing the dimensionality of entanglement has been shown to improve robustness and channel capacities in secure quantum communications. Here we report on the distribution of genuine high-dimensional entanglement via a 1.2-km-long free-space link across Vienna. We exploit hyperentanglement, that is, simultaneous entanglement in polarization and energy-time bases, to encode quantum information, and observe high-visibility interference for successive correlation measurements in each degree of freedom. These visibilities impose lower bounds on entanglement in each subspace individually and certify four-dimensional entanglement for the hyperentangled system. The high-fidelity transmission of high-dimensional entanglement under real-world atmospheric link conditions represents an important step towards long-distance quantum communications with more complex quantum systems and the implementation of advanced quantum experiments with satellite links.

  1. Collagen cross-link excretion during space flight and bed rest

    Science.gov (United States)

    Smith, S. M.; Nillen, J. L.; Leblanc, A.; Lipton, A.; Demers, L. M.; Lane, H. W.; Leach, C. S.; LeBlanc, A. (Principal Investigator)

    1998-01-01

    Extended exposure to weightlessness results in bone loss. However, little information exists as to the precise nature or time course of this bone loss. Bone resorption results in the release of collagen breakdown products, including N-telopeptide and the pyridinium (PYD) cross-links, pyridinoline and deoxypyridinoline. Urinary pyridinoline and deoxypyridinoline are known to increase during bed rest. We assessed excretion of PYD cross-links and N-telopeptide before, during, and after long (28-day, 59-day, and 84-day) Skylab missions, as well as during short (14-day) and long (119-day) bed-rest studies. During space flight, the urinary cross-link excretion level was twice those observed before flight. Urinary excretion levels of the collagen breakdown products were also 40-50% higher, during short and long bed rest, than before. These results clearly show that the changes in bone metabolism associated with space flight involve increased resorption. The rate of response (i.e. within days to weeks) suggests that alterations in bone metabolism are an early effect of weightlessness. These studies are important for a better understanding of bone metabolism in space crews and in those who are bedridden.

  2. Space Link Extension (SLE) Emulation for High-Throughput Network Communication

    Science.gov (United States)

    Murawski, Robert W.; Tchorowski, Nicole; Golden, Bert

    2014-01-01

    As the data rate requirements for space communications increases, significant stress is placed not only on the wireless satellite communication links, but also on the ground networks which forward data from end-users to remote ground stations. These wide area network (WAN) connections add delay and jitter to the end-to-end satellite communication link, effects which can have significant impacts on the wireless communication link. It is imperative that any ground communication protocol can react to these effects such that the ground network does not become a bottleneck in the communication path to the satellite. In this paper, we present our SCENIC Emulation Lab testbed which was developed to test the CCSDS SLE protocol implementations proposed for use on future NASA communication networks. Our results show that in the presence of realistic levels of network delay, high-throughput SLE communication links can experience significant data rate throttling. Based on our observations, we present some insight into why this data throttling happens, and trace the probable issue back to non-optimal blocking communication which is sup-ported by the CCSDS SLE API recommended practices. These issues were presented as well to the SLE implementation developers which, based on our reports, developed a new release for SLE which we show fixes the SLE blocking issue and greatly improves the protocol throughput. In this paper, we also discuss future developments for our end-to-end emulation lab and how these improvements can be used to develop and test future space communication technologies.

  3. The space-math link in preschool boys and girls: Importance of mental transformation, targeting accuracy, and spatial anxiety.

    Science.gov (United States)

    Wong, Wang I

    2017-06-01

    Spatial abilities are pertinent to mathematical competence, but evidence of the space-math link has largely been confined to older samples and intrinsic spatial abilities (e.g., mental transformation). The roles of gender and affective factors are also unclear. This study examined the correlations between counting ability, mental transformation, and targeting accuracy in 182 Hong Kong preschoolers, and whether these relationships were weaker at higher spatial anxiety levels. Both spatial abilities related with counting similarly for boys and girls. Targeting accuracy also mediated the male advantage in counting. Interestingly, spatial anxiety moderated the space-math links, but differently for boys and girls. For boys, spatial abilities were irrelevant to counting at high anxiety levels; for girls, the role of anxiety on the space-math link is less clear. Results extend the evidence base of the space-math link to include an extrinsic spatial ability (targeting accuracy) and have implications for intervention programmes. Statement of contribution What is already known on this subject? Much evidence of a space-math link in adolescent and adult samples and for intrinsic spatial abilities. What does this study add? Extended the space-math link to include both intrinsic and extrinsic spatial abilities in a preschool sample. Showed how spatial anxiety moderated the space-math link differently for boys and girls. © 2016 The British Psychological Society.

  4. Feasibility Analysis Of Free Space Earth To Satellite Optical Link In Tropical Region

    Directory of Open Access Journals (Sweden)

    Norhanis Aida M. Nor

    2012-01-01

    Full Text Available Free Space Optics (FSO becomes a great attention because of the chances in transmitting data up to 2.5Gbps. There are a lot of advantages offered by FSO such as easily deployment with saving time and cost and no electromagnetic interference. In spite of the advantages, FSO has an uncontrolled drawback which is highly sensitive to atmospheric phenomena because uses air as tranmission medium. Current studies and researches are only focusing on FSO terrestrial link with short path length and based on data from temperate region. Therefore, this paper is aiming to provide feasibility analysis of FSO link from earth to satellite especially Low Earth Orbit (LEO based on atmospheric data in tropical region. The analysis will include the losses from geometrical attenuation, absorption, scintillation, haze attenuation, and rain attenuation. ABSTRAK: Ruang Bebas Optik (Free Space Optics (FSO mendapat perhatian kerana kebolehannya memancarkan data pada kelajuan tinggi. Di sebalik kelebihannya, FSO amat sensitif terhadap fenomena atmosfera kerana ia menggunakan udara sebagai perantara transmisi. Penyelidikan dan kajian terkini hanya memfokus kepada jalinan darat FSO dengan kepanjangan jarak pendek dan bergantung kepada kawasan tenang.  Oleh itu, kertas ini menyasarkan untuk memberikan analisis kebolehlaksanaan  jalinan FSO dari bumi ke satelit terutamanya Orbit Rendah Bumi (Low Earth Orbit (LEO bergantung kepada data atmosfera di kawasan tropika. Analisa termasuklah kehilangannya akibat pengecilan geometri, penyerapan, kelipan, pelemahan jerebu dan pelemahan hujan.KEYWORDS:  feasibility; Free Space Optics; availability; atmospheric attenuation; beam divergence angle; elevation angle

  5. Developing a Standard Method for Link-Layer Security of CCSDS Space Communications

    Science.gov (United States)

    Biggerstaff, Craig

    2009-01-01

    Communications security for space systems has been a specialized field generally far removed from considerations of mission interoperability and cross-support in fact, these considerations often have been viewed as intrinsically opposed to security objectives. The space communications protocols defined by the Consultative Committee for Space Data Systems (CCSDS) have a twenty-five year history of successful use in over 400 missions. While the CCSDS Telemetry, Telecommand, and Advancing Orbiting Systems protocols for use at OSI Layer 2 are operationally mature, there has been no direct support within these protocols for communications security techniques. Link-layer communications security has been successfully implemented in the past using mission-unique methods, but never before with an objective of facilitating cross-support and interoperability. This paper discusses the design of a standard method for cryptographic authentication, encryption, and replay protection at the data link layer that can be integrated into existing CCSDS protocols without disruption to legacy communications services. Integrating cryptographic operations into existing data structures and processing sequences requires a careful assessment of the potential impediments within spacecraft, ground stations, and operations centers. The objective of this work is to provide a sound method for cryptographic encapsulation of frame data that also facilitates Layer 2 virtual channel switching, such that a mission may procure data transport services as needed without involving third parties in the cryptographic processing, or split independent data streams for separate cryptographic processing.

  6. Analysis of fog effects on terrestrial Free Space optical communication links

    KAUST Repository

    Esmail, Maged Abdullah

    2016-07-26

    In this paper, we consider and examine fog measurement data, coming from several locations in Europe and USA, and attempt to derive a unified model for fog attenuation in free space optics (FSO) communication links. We evaluate and compare the performance of our proposed model to that of many well-known alternative models. We found that our proposed model, achieves an average RMSE that outperforms them by more than 9 dB. Furthermore, we have studied the performance of the FSO system using different performance metrics such as signal-to-noise (SNR) ratio, bit error rate (BER), and channel capacity. Our results show that FSO is a short range technology. Therefore, FSO is expected to find its place in future networks that will have small cell size, i.e., <1 km diameter. Moreover, our investigation shows that under dense fog, it is difficult to maintain a communications link because of the high signal attenuation, which requires switching the communications to RF backup. Our results show that increasing the transmitted power will improve the system performance under light fog. However, under heavy fog, the effect is minor. To enhance the system performance under low visibility range, multi-hop link is used which can enhance the power budget by using short segments links. Using 22 dBm transmitted power, we obtained BER=10-3 over 1 km link length with 600 m visibility range which corresponds to light fog. However, under lower visibility range equals 40 m that corresponds to dense fog, we obtained the same BER but over 200 m link length. © 2016 IEEE.

  7. Exploring context and content links in social media: a latent space method.

    Science.gov (United States)

    Qi, Guo-Jun; Aggarwal, Charu; Tian, Qi; Ji, Heng; Huang, Thomas S

    2012-05-01

    Social media networks contain both content and context-specific information. Most existing methods work with either of the two for the purpose of multimedia mining and retrieval. In reality, both content and context information are rich sources of information for mining, and the full power of mining and processing algorithms can be realized only with the use of a combination of the two. This paper proposes a new algorithm which mines both context and content links in social media networks to discover the underlying latent semantic space. This mapping of the multimedia objects into latent feature vectors enables the use of any off-the-shelf multimedia retrieval algorithms. Compared to the state-of-the-art latent methods in multimedia analysis, this algorithm effectively solves the problem of sparse context links by mining the geometric structure underlying the content links between multimedia objects. Specifically for multimedia annotation, we show that an effective algorithm can be developed to directly construct annotation models by simultaneously leveraging both context and content information based on latent structure between correlated semantic concepts. We conduct experiments on the Flickr data set, which contains user tags linked with images. We illustrate the advantages of our approach over the state-of-the-art multimedia retrieval techniques.

  8. Ergodic Capacity Analysis of Free-Space Optical Links with Nonzero Boresight Pointing Errors

    KAUST Repository

    Ansari, Imran Shafique

    2015-04-01

    A unified capacity analysis of a free-space optical (FSO) link that accounts for nonzero boresight pointing errors and both types of detection techniques (i.e. intensity modulation/ direct detection as well as heterodyne detection) is addressed in this work. More specifically, an exact closed-form expression for the moments of the end-to-end signal-to-noise ratio (SNR) of a single link FSO transmission system is presented in terms of well-known elementary functions. Capitalizing on these new moments expressions, we present approximate and simple closedform results for the ergodic capacity at high and low SNR regimes. All the presented results are verified via computer-based Monte-Carlo simulations.

  9. Input Harmonic Analysis on the Slim DC-Link Drive Using Harmonic State Space Model

    DEFF Research Database (Denmark)

    Yang, Feng; Kwon, Jun Bum; Wang, Xiongfei

    2017-01-01

    variation according to the switching instant, the harmonics at the steady-state condition, as well as the coupling between the multiple harmonic impedances. By using this model, the impaction on the harmonics performance by the film capacitor and the grid inductance is derived. Simulation and experimental......The harmonic performance of the slim dc-link adjustable speed drives has shown good performance in some studies but poor in some others. The contradiction indicates that a feasible theoretical analysis is still lacking to characterize the harmonic distortion for the slim dc-link drive. Considering...... the shortcomings of the present harmonic analysis methods, such as the time-domain simulation, or the Fourier analysis, this paper proposes a Harmonic State Space model to study the harmonics performance for this type of drive. In this study, this model is utilized to describe the behavior of the harmonic...

  10. Patulous Subarachnoid Space of the Optic Nerve Associated with X-Linked Hypophosphatemic Rickets.

    Science.gov (United States)

    Galvez-Ruiz, Alberto; Chaudhry, Imtiaz

    2013-01-01

    Although the deficiency forms are the most common manifestations of rickets, there are other forms of rickets that are resistant to vitamin D. Of these, the most common is X-linked hypophosphatemic rickets. Rickets represents a group of multiple cranial bone disorders-craniosynostosis and the presence of Chari I malformation being the most notable-that explain the increase in intracranial pressure. We present a 4-year-old patient with an unusual association of X-linked hypophosphataemic rickets, bilateral proptosis, and prominent bilateral widening of the optic nerve sheaths. Although the association between intracranial hypertension and rickets is known, to the best of our knowledge, such a prominent distention of the subarachnoid space of the optic nerve without papilloedema has not been previously described.

  11. A comparison of superconductor and manganin technology for electronic links used in space mission applications

    Science.gov (United States)

    Caton, R.; Selim, R.; Buoncristiani, A. M.

    1992-01-01

    The electronic link connecting cryogenically cooled radiation detectors to data acquisition and signal processing electronics at higher temperatures contributes significantly to the total heat load on spacecraft cooling systems that use combined mechanical and cryogenic liquid cooling. Using high transition temperature superconductors for this link has been proposed to increase the lifetime of space missions. Herein, several YBCO (YBa2Cu3O7) superconductor-substrate combinations were examined and total heat loads were compared to manganin wire technology in current use. Using numerical solutions to the heat-flow equations, it is shown that replacing manganin technology with YBCO thick film technology can extend a 7-year mission by up to 1 year.

  12. Deep-Space Ka-Band Link Priority Data Protection: Pre-Emptive Retransmission vs. Margin

    Science.gov (United States)

    Shambayati, Shervin

    2009-01-01

    In this paper the performance of two preemptive retransmission schemes for protection of priority data over deep-space Ka-band links is evaluated. The first scheme merges the correctly received bit from each transmission to create the most complete set of priority data for each pass (bit merge). The second scheme (symbol combining) combines the soft symbols received from each transmission of the priority data to increase the priority data's signal to noise ratio (SNR), thus increasing the liklihood of the correct reception.

  13. Hardware and Software Integration to Support Real-Time Space-Link Emulation

    Science.gov (United States)

    Murawski, Robert; Bhasin, Kul; Bittner, David

    2012-01-01

    Prior to operational use, communications hardware and software must be thoroughly tested and verified. In space-link communications, field testing equipment can be prohibitively expensive and cannot test to non-ideal situations. In this paper, we show how software and hardware emulation tools can be used to accurately model the characteristics of a satellite communication channel in a lab environment. We describe some of the challenges associated with developing an emulation lab and present results to demonstrate the channel modeling. We then show how network emulation software can be used to extend a hardware emulation model without requiring additional network and channel simulation hardware.

  14. Hardware and Software Integration to Support Real-Time Space Link Emulation

    Science.gov (United States)

    Murawski, Robert; Bhasin, Kul; Bittner, David; Sweet, Aaron; Coulter, Rachel; Schwab, Devin

    2012-01-01

    Prior to operational use, communications hardware and software must be thoroughly tested and verified. In space-link communications, field testing equipment can be prohibitively expensive and cannot test to non-ideal situations. In this paper, we show how software and hardware emulation tools can be used to accurately model the characteristics of a satellite communication channel in a lab environment. We describe some of the challenges associated with developing an emulation lab and present results to demonstrate the channel modeling. We then show how network emulation software can be used to extend a hardware emulation model without requiring additional network and channel simulation hardware.

  15. Exploring links between foundation phase teachers’ content knowledge and their example spaces

    Directory of Open Access Journals (Sweden)

    Samantha Morrison

    2013-12-01

    Full Text Available This paper explores two foundation phase teachers’ example spaces (a space in the mind where examples exist when teaching number-related topics in relation to snapshots of their content knowledge (CK. Data was collected during a pilot primary maths for teaching course that included assessments of teacher content knowledge (CK. An analysis of a content-knowledge focused pre-test developed for the larger study indicated a relatively high score for one teacher and a low score for the other. Using Rowland’s (2008 framework, an analysis of classroom practice showed associations between a higher CK and the extent of a teacher’s example space and more coherent connections between different representational forms. Although no hard claims or generalisations of the link between teachers’ example spaces and their level of mathematics content knowledge can be made here, this study reinforces evidence of the need to increase teachers’ CK from a pedagogic perspective in order to raise the level of mathematics teaching and learning in the South African landscape.

  16. Harmonic Brain Modes: A Unifying Framework for Linking Space and Time in Brain Dynamics.

    Science.gov (United States)

    Atasoy, Selen; Deco, Gustavo; Kringelbach, Morten L; Pearson, Joel

    2017-09-01

    A fundamental characteristic of spontaneous brain activity is coherent oscillations covering a wide range of frequencies. Interestingly, these temporal oscillations are highly correlated among spatially distributed cortical areas forming structured correlation patterns known as the resting state networks, although the brain is never truly at "rest." Here, we introduce the concept of harmonic brain modes-fundamental building blocks of complex spatiotemporal patterns of neural activity. We define these elementary harmonic brain modes as harmonic modes of structural connectivity; that is, connectome harmonics, yielding fully synchronous neural activity patterns with different frequency oscillations emerging on and constrained by the particular structure of the brain. Hence, this particular definition implicitly links the hitherto poorly understood dimensions of space and time in brain dynamics and its underlying anatomy. Further we show how harmonic brain modes can explain the relationship between neurophysiological, temporal, and network-level changes in the brain across different mental states ( wakefulness, sleep, anesthesia, psychedelic). Notably, when decoded as activation of connectome harmonics, spatial and temporal characteristics of neural activity naturally emerge from the interplay between excitation and inhibition and this critical relation fits the spatial, temporal, and neurophysiological changes associated with different mental states. Thus, the introduced framework of harmonic brain modes not only establishes a relation between the spatial structure of correlation patterns and temporal oscillations (linking space and time in brain dynamics), but also enables a new dimension of tools for understanding fundamental principles underlying brain dynamics in different states of consciousness.

  17. Modelling of 10 Gbps Free Space Optics Communication Link Using Array of Receivers in Moderate and Harsh Weather Conditions

    Science.gov (United States)

    Gupta, Amit; Shaina, Nagpal

    2017-08-01

    Intersymbol interference and attenuation of signal are two major parameters affecting the quality of transmission in Free Space Optical (FSO) Communication link. In this paper, the impact of these parameters on FSO communication link is analysed for delivering high-quality data transmission. The performance of the link is investigated under the influence of amplifier in the link. The performance parameters of the link like minimum bit error rate, received signal power and Quality factor are examined by employing erbium-doped fibre amplifier in the link. The effects of amplifier are visualized with the amount of received power. Further, the link is simulated for moderate weather conditions at various attenuation levels on transmitted signal. Finally, the designed link is analysed in adverse weather conditions by using high-power laser source for optimum performance.

  18. High Precision Ranging and Range-Rate Measurements over Free-Space-Laser Communication Link

    Science.gov (United States)

    Yang, Guangning; Lu, Wei; Krainak, Michael; Sun, Xiaoli

    2016-01-01

    We present a high-precision ranging and range-rate measurement system via an optical-ranging or combined ranging-communication link. A complete bench-top optical communication system was built. It included a ground terminal and a space terminal. Ranging and range rate tests were conducted in two configurations. In the communication configuration with 622 data rate, we achieved a two-way range-rate error of 2 microns/s, or a modified Allan deviation of 9 x 10 (exp -15) with 10 second averaging time. Ranging and range-rate as a function of Bit Error Rate of the communication link is reported. They are not sensitive to the link error rate. In the single-frequency amplitude modulation mode, we report a two-way range rate error of 0.8 microns/s, or a modified Allan deviation of 2.6 x 10 (exp -15) with 10 second averaging time. We identified the major noise sources in the current system as the transmitter modulation injected noise and receiver electronics generated noise. A new improved system will be constructed to further improve the system performance for both operating modes.

  19. Space-Time Localization of Plasma Turbulence Using Multiple Spacecraft Radio Links

    Science.gov (United States)

    Armstrong, John W.; Estabrook, Frank B.

    2011-01-01

    Space weather is described as the variability of solar wind plasma that can disturb satellites and systems and affect human space exploration. Accurate prediction requires information of the heliosphere inside the orbit of the Earth. However, for predictions using remote sensing, one needs not only plane-of-sky position but also range information the third spatial dimension to show the distance to the plasma disturbances and thus when they might propagate or co-rotate to create disturbances at the orbit of the Earth. Appropriately processed radio signals from spacecraft having communications lines-of-sight passing through the inner heliosphere can be used for this spacetime localization of plasma disturbances. The solar plasma has an electron density- and radio-wavelength-dependent index of refraction. An approximately monochromatic wave propagating through a thin layer of plasma turbulence causes a geometrical-optics phase shift proportional to the electron density at the point of passage, the radio wavelength, and the thickness of the layer. This phase shift is the same for a wave propagating either up or down through the layer at the point of passage. This attribute can be used for space-time localization of plasma irregularities. The transfer function of plasma irregularities to the observed time series depends on the Doppler tracking mode. When spacecraft observations are in the two-way mode (downlink radio signal phase-locked to an uplink radio transmission), plasma fluctuations have a two-pulse response in the Doppler. In the two-way mode, the Doppler time series y2(t) is the difference between the frequency of the downlink signal received and the frequency of a ground reference oscillator. A plasma blob localized at a distance x along the line of sight perturbs the phase on both the up and down link, giving rise to two events in the two-way tracking time series separated by a time lag depending the blob s distance from the Earth: T2-2x/c, where T2 is the

  20. High power free space optical link for rapid energy and data transmission

    Science.gov (United States)

    Dhadwal, Harbans S.; Rastegar, Jahangir; Feng, Dake; Kwok, Philip

    2016-05-01

    Design and experimental data for a high power laser diode based free space point-to-point optical power/data link is presented. In time critical power up applications, such as providing power and guidance information to a munition shell just prior to deployment, energy of the order of 100 J needs to be transferred in under 10 s. Current inductive technology is slow and broadcasts a radio-frequency signal which is undesirable for stealth operation. Rapid energy transfer times require high irradiance levels at the surface of the photovoltaic cells, typically, exceeding 1000X suns. Through efficient thermal design of heat sinks, high optical to electrical power conversion efficiencies of 50%, which are usually attainable at low power levels of 1 W, are achievable at higher power levels.

  1. On the Performance Analysis of Free-Space Optical Links under Generalized Turbulence and Misalignment Models

    KAUST Repository

    AlQuwaiee, Hessa

    2016-11-01

    One of the potential solutions to the radio frequency (RF) spectrum scarcity problem is optical wireless communications (OWC), which utilizes the unlicensed optical spectrum. Long-range outdoor OWC are usually referred to in the literature as free-space optical (FSO) communications. Unlike RF systems, FSO is immune to interference and multi-path fading. Also, the deployment of FSO systems is flexible and much faster than optical fibers. These attractive features make FSO applicable for broadband wireless transmission such as optical fiber backup, metropolitan area network, and last mile access. Although FSO communication is a promising technology, it is negatively affected by two physical phenomenon, namely, scintillation due to atmospheric turbulence and pointing errors. These two critical issues have prompted intensive research in the last decade. To quantify the effect of these two factors on FSO system performance, we need effective mathematical models. In this work, we propose and study a generalized pointing error model based on the Beckmann distribution. Then, we aim to generalize the FSO channel model to span all turbulence conditions from weak to strong while taking pointing errors into consideration. Since scintillation in FSO is analogous to the fading phenomena in RF, diversity has been proposed too to overcome the effect of irradiance fluctuations. Thus, several combining techniques of not necessarily independent dual-branch free-space optical links were investigated over both weak and strong turbulence channels in the presence of pointing errors. On another front, improving the performance, enhancing the capacity and reducing the delay of the communication link has been the motivation of any newly developed schemes, especially for backhauling. Recently, there has been a growing interest in practical systems to integrate RF and FSO technologies to solve the last mile bottleneck. As such, we also study in this thesis asymmetric an RF-FSO dual-hop relay

  2. Simulation of turbulences and fog effects on the free space optical link inside of experimental box

    Science.gov (United States)

    Latal, Jan; Vitasek, Jan; Hajek, Lukas; Vanderka, Ales; Koudelka, Petr; Kepak, Stanislav; Vasinek, Vladimir

    2016-12-01

    This paper deals with problematic of Free Space Optical (FSO) Links. The theoretical part describes the effects of atmospheric transmission environment on these FSO connections. The practical part is focused on the creation of an appropriate experimental workplace for turbulences simulation (mechanical and thermal turbulences), fog effects and subsequent measurement of these effects. For definition how big impact these effects on the FSO system have is used the statistical analysis and simulation software Optiwave. Overall there were tested three optical light sources operating at wavelengths of 632.8 nm, 850 nm and 1550 nm respectively. Influences of simulated atmospheric effects on the signal attenuation were observed. Within the frame of simulation in Optiwave software there were studied influences of attenuation on given wavelengths in form of FSO link transmission parameters degradation. Also for the purposes of real measurements it was necessary to fabricate an experimental box. This box was constructed with sizes of 2.5 and 5 meters and was used for simulation of atmospheric environment.

  3. Probabilistic Model for Free-Space Optical Links Under Continental Fog Conditions

    Directory of Open Access Journals (Sweden)

    Marzuki

    2010-09-01

    Full Text Available The error characteristics of a free-space optical (FSO channel are significantly different from the fiber based optical links and thus require a deep physical understanding of the propagation channel. In particular different fog conditions greatly influence the optical transmissions and thus a channel model is required to estimate the detrimental fog effects. In this paper we shall present the probabilistic model for radiation fog from the measured data over a 80 m FSO link installed at Graz, Austria. The fog events are classified into thick fog, moderate fog, light fog and general fog based on the international code of visibility range. We applied some probability distribution functions (PDFs such as Kumaraswamy, Johnson SB and Logistic distribution, to the actual measured optical attenuations. The performance of each distribution is evaluated by Q-Q and P-P plots. It is found that Kumaraswamy distribution is the best fit for general fog, while Logistic distribution is the optimum choice for thick fog. On the other hand, Johnson SB distribution best fits the moderate and light fog related measured attenuation data. The difference in these probabilistic models and the resultant variation in the received signal strength under different fog types needs to be considered in designing an efficient FSO system.

  4. Linking earthworm activity and hydrologically effective macropores in space and time

    Science.gov (United States)

    Schneider, Anne-Kathrin; van Schaik, Loes; Zangerlé, Anne; Hohenbrink, Tobias Ludwig; Schröder, Boris

    2017-04-01

    Earthworms create macropore systems through their burrowing activity. Preferential flow through macropores leads to increased infiltration and solute leaching. The hydrological effectiveness of these macropore systems varies in space and time depending on earthworm activity and their ability to refill their burrows to sustain seasonal or occasional drought periods. Thus, linking earthworm activity and spatiotemporal variability in hydrologically effective macropores in an ecohydrological framework yields crucial information for parameterization of macropore flow models. We investigated earthworm abundances and macropore densities by rainfall infiltration experiments with six campaigns during one year at six field sites in Luxembourg in order to link earthworm activity and macropore effectiveness. We used correlative models to predict (i) spatiotemporal variability in earthworm abundances based on weather and topology-derived variables, and (ii) spatiotemporal variability in effective macropore densities based on the same set of predictors as well as earthworm abundances. In this presentation we will show one example for predicting a one-year, daily resolved time series of the earthworm species Aporrectodea longa showing the highest predictive value and the effective macropores of 2-6 mm diameter in 10 cm soil depth. From this time series we picked out four characteristic dates for which we predicted the spatial distribution of A. longa and the related effective macropores for a small-scale catchment at 5 m resolution. We discuss how the outputs of this study (macropore numbers and their uncertainties) can be used to parameterize macropore flow in hydrological models.

  5. Performance Analysis of Free-Space Optical Links Over Malaga (M) Turbulence Channels with Pointing Errors

    KAUST Repository

    Ansari, Imran Shafique

    2015-08-12

    In this work, we present a unified performance analysis of a free-space optical (FSO) link that accounts for pointing errors and both types of detection techniques (i.e. intensity modulation/direct detection (IM/DD) as well as heterodyne detection). More specifically, we present unified exact closedform expressions for the cumulative distribution function, the probability density function, the moment generating function, and the moments of the end-to-end signal-to-noise ratio (SNR) of a single link FSO transmission system, all in terms of the Meijer’s G function except for the moments that is in terms of simple elementary functions. We then capitalize on these unified results to offer unified exact closed-form expressions for various performance metrics of FSO link transmission systems, such as, the outage probability, the scintillation index (SI), the average error rate for binary and M-ary modulation schemes, and the ergodic capacity (except for IM/DD technique, where we present closed-form lower bound results), all in terms of Meijer’s G functions except for the SI that is in terms of simple elementary functions. Additionally, we derive the asymptotic results for all the expressions derived earlier in terms of Meijer’s G function in the high SNR regime in terms of simple elementary functions via an asymptotic expansion of the Meijer’s G function. We also derive new asymptotic expressions for the ergodic capacity in the low as well as high SNR regimes in terms of simple elementary functions via utilizing moments. All the presented results are verified via computer-based Monte-Carlo simulations.

  6. Performance analysis of stationary Hadamard matrix diffusers in free-space optical communication links

    Science.gov (United States)

    Burrell, Derek J.; Middlebrook, Christopher T.

    2017-08-01

    Wireless communication systems that employ free-space optical links in place of radio/microwave technologies carry substantial benefits in terms of data throughput, network security and design efficiency. Along with these advantages comes the challenge of counteracting signal degradation caused by atmospheric turbulence in free-space environments. A fully coherent laser source experiences random phase delays along its traversing path in turbulent conditions forming a speckle pattern and lowering the received signal-to-noise ratio upon detection. Preliminary research has shown that receiver-side speckle contrast may be significantly reduced and signal-to-noise ratio increased accordingly through the use of a partially coherent light source. While dynamic diffusers and adaptive optics solutions have been proven effective, they also add expense and complexity to a system that relies on accessibility and robustness for successful implementation. A custom Hadamard diffractive matrix design is used to statically induce partial coherence in a transmitted beam to increase signal-to-noise ratio for experimental turbulence scenarios. Atmospheric phase screens are generated using an open-source software package and subsequently loaded into a spatial light modulator using nematic liquid crystals to modulate the phase.

  7. Channel modelling for free-space optical inter-HAP links using adaptive ARQ transmission

    Science.gov (United States)

    Parthasarathy, S.; Giggenbach, D.; Kirstädter, A.

    2014-10-01

    Free-space optical (FSO) communication systems have seen significant developments in recent years due to growing need for very high data rates and tap-proof communication. The operation of an FSO link is suited to diverse variety of applications such as satellites, High Altitude Platforms (HAPs), Unmanned Aerial Vehicles (UAVs), aircrafts, ground stations and other areas involving both civil and military situations. FSO communication systems face challenges due to different effects of the atmospheric channel. FSO channel primarily suffers from scintillation effects due to Index of Refraction Turbulence (IRT). In addition, acquisition and pointing becomes more difficult because of the high directivity of the transmitted beam: Miss-pointing of the transmitted beam and tracking errors at the receiver generate additional fading of the optical signal. High Altitude Platforms (HAPs) are quasi-stationary vehicles operating in the stratosphere. The slowly varying but precisely determined time-of-flight of the Inter-HAP channel adds to its characteristics. To propose a suitable ARQ scheme, proper theoretical understanding of the optical atmospheric propagation and modeling of a specific scenario FSO channel is required. In this paper, a bi-directional symmetrical Inter-HAP link has been selected and modeled. The Inter-HAP channel model is then investigated via simulations in terms of optical scintillation induced by IRT and in presence of pointing error. The performance characteristic of the model is then quantified in terms of fading statistics from which the Packet Error Probability (PEP) is calculated. Based on the PEP characteristics, we propose suitable ARQ schemes.

  8. Experimental demonstration of multi-aperture digital coherent combining over a 3.2-km free-space link

    Science.gov (United States)

    Geisler, D. J.; Yarnall, T. M.; Schieler, C. M.; Stevens, M. L.; Robinson, B. S.; Hamilton, S. A.

    2017-02-01

    The next generation free-space optical communications infrastructure will need to support a wide variety of space-to-ground links. As a result of the limited size, weight, and power on space-borne assets, the ground terminals need to scale efficiently to large collection areas to support extremely long link distances or high data rates. Recent advances in integrated digital coherent receivers enable the coherent combining (i.e., full-field addition) of signals from several small apertures to synthesize an effective single large aperture. In this work, we experimentally demonstrate the coherent combining of signals received by four independent receive chains after propagation through a 3:2-km atmospheric channel. Measured results show the practicality of coherently combining the four received signals via digital signal processing after transmission through a turbulent atmosphere. In particular, near-lossless combining is demonstrated using the technique of maximal ratio combining.

  9. Fading Losses on the LCRD Free-Space Optical Link Due to Channel Turbulence

    Science.gov (United States)

    Moision, Bruce; Piazzolla, Sabino; Hamkins, Jon

    2013-01-01

    The Laser Communications Relay Demonstration (LCRD) will implement an optical communications link between a pair of Earth terminals via an Earth-orbiting satellite relay. Clear air turbulence over the communication paths will cause random fluctuations, or fading, in the received signal irradiance. In this paper we characterize losses due to fading caused by clear air turbulence. We illustrate the performance of a representative relay link, utilizing a channel interleaver and error-correction-code to mitigate fading, and provide a method to quickly determine the link performance.

  10. Multi-Scale Singularity Trees: Soft-Linked Scale-Space Hierarchies

    DEFF Research Database (Denmark)

    Somchaipeng, Kerawit; Sporring, Jon; Kreiborg, Sven

    2005-01-01

    We consider images as manifolds embedded in a hybrid of a high dimensional space of coordinates and features. Using the proposed energy functional and mathematical landmarks, images are partitioned into segments. The nesting of image segments occurring at catastrophe points in the scale-space is ...

  11. VillageLink: A channel allocation technique for wide-area white space networks

    CSIR Research Space (South Africa)

    Pejovic, V

    2015-01-01

    Full Text Available to a graph coloring problem. In white spaces, the wide range of available channels leads to drastic differences in propagation among channels. These differences stem from the variation of free space propagation over frequencies, but also from antenna...

  12. SpaceTree: Supporting Exploration in Large Node Link Tree, Design Evolution and Empirical Evaluation

    National Research Council Canada - National Science Library

    Plaisant, Catherine; Grosjean, Jesse; Bedersonn, Benjamin B

    2002-01-01

    .... It adds dynamic rescaling of branches of the tree to best fit the available screen space, optimized camera movement, and the use of preview icons summarizing the topology of the branches that cannot be expanded...

  13. Experimental characterization of a 400 Gbit/s orbital angular momentum multiplexed free-space optical link over 120 m.

    Science.gov (United States)

    Ren, Yongxiong; Wang, Zhe; Liao, Peicheng; Li, Long; Xie, Guodong; Huang, Hao; Zhao, Zhe; Yan, Yan; Ahmed, Nisar; Willner, Asher; Lavery, Martin P J; Ashrafi, Nima; Ashrafi, Solyman; Bock, Robert; Tur, Moshe; Djordjevic, Ivan B; Neifeld, Mark A; Willner, Alan E

    2016-02-01

    We experimentally demonstrate and characterize the performance of a 400-Gbit/s orbital angular momentum (OAM) multiplexed free-space optical link over 120 m on the roof of a building. Four OAM beams, each carrying a 100-Gbit/s quadrature-phase-shift-keyed channel are multiplexed and transmitted. We investigate the influence of channel impairments on the received power, intermodal crosstalk among channels, and system power penalties. Without laser tracking and compensation systems, the measured received power and crosstalk among OAM channels fluctuate by 4.5 dB and 5 dB, respectively, over 180 s. For a beam displacement of 2 mm that corresponds to a pointing error less than 16.7 μrad, the link bit error rates are below the forward error correction threshold of 3.8×10(-3) for all channels. Both experimental and simulation results show that power penalties increase rapidly when the displacement increases.

  14. 512-channel vertical-cavity surface-emitting laser based free-space optical link.

    Science.gov (United States)

    Châteauneuf, Marc; Kirk, Andrew G; Plant, David V; Yamamoto, Tsuyoshi; Ahearn, John D

    2002-09-10

    A vertical-cavity surface-emitting laser based bidirectional free-space optical interconnect has been implemented to interconnect two printed circuit boards. A total of 512 clustered channels with a density of 2844 channels/cm2 are transmitted over a distance of 83 mm. The optical interconnect is a combination of refractive microlenses and diffractive minilens relays.

  15. Estimation of optical attenuation in reduced visibility conditions in different environments across free space optics link

    Czech Academy of Sciences Publication Activity Database

    Dev, K.; Nebuloni, R.; Capsoni, C.; Fišer, Ondřej; Brázda, V.

    2017-01-01

    Roč. 11, č. 12 (2017), s. 1708-1713 ISSN 1751-8725 Institutional support: RVO:68378289 Keywords : light attenuation * optical sensors * free-space optical communication Subject RIV: DG - Athmosphere Sciences, Meteorology OBOR OECD: Meteorology and atmospheric sciences Impact factor: 1.187, year: 2016 http://digital- library .theiet.org/content/journals/10.1049/iet-map.2016.0872

  16. Personal Space - linking you with the rest of the world through the Universe

    Science.gov (United States)

    Topinka, M.; O Boyle, E.; Hanlon, L.; Simpson, R.

    2014-12-01

    The GLORIA project aims to bring astronomy to anyone with an Internet connection, by making a global network of robotic telescopes available for use by the public. But being given the opportunity to observe anywhere in the universe is a bit like being faced with a blank canvas - where do you start? `Personal Space' is a response to this challenge that emerged from an art-science collaboration between an astronomer and an artist.

  17. Follow the link: Digital Tracings of a Multi-Sited Space of Research

    DEFF Research Database (Denmark)

    Munk, Anders Kristian

    The paper discusses the use of digital methods as an alternative way of generating what George Marcus calls 'posited logics of association' for use in multi-sited fieldwork. I draw on cases from an ongoing research project on the new nordic food movement and its on- and off-line assemblages. I do...... doing so I demonstrate how methods which are native to the digital domain - such as the link or the like as a valuation metric - may be re-appropriated as strategies in more ethnographic styles of work....

  18. Anthropogenic reaction parameters--the missing link between chemical intuition and the available chemical space.

    Science.gov (United States)

    Keserű, György M; Soós, Tibor; Kappe, C Oliver

    2014-08-07

    How do skilled synthetic chemists develop good intuitive expertise? Why can we only access such a small amount of the available chemical space-both in terms of the reactions used and the chemical scaffolds we make? We argue here that these seemingly unrelated questions have a common root and are strongly interdependent. We performed a comprehensive analysis of organic reaction parameters dating back to 1771 and discovered that there are several anthropogenic factors that limit reaction parameters and thus the scope of synthetic chemistry. Nevertheless, many of the anthropogenic limitations such as narrow parameter space and the opportunity for rapid and clear feedback on the progress of reactions appear to be crucial for the acquisition of valid and reliable chemical intuition. In parallel, however, all of these same factors represent limitations for the exploration of available chemistry space and we argue that these are thus at least partly responsible for limited access to new chemistries. We advocate, therefore, that the present anthropogenic boundaries can be expanded by a more conscious exploration of "off-road" chemistry that would also extend the intuitive knowledge of trained chemists.

  19. Exploring Protein Dynamics Space: The Dynasome as the Missing Link between Protein Structure and Function

    Science.gov (United States)

    Hensen, Ulf; Meyer, Tim; Haas, Jürgen; Rex, René; Vriend, Gert; Grubmüller, Helmut

    2012-01-01

    Proteins are usually described and classified according to amino acid sequence, structure or function. Here, we develop a minimally biased scheme to compare and classify proteins according to their internal mobility patterns. This approach is based on the notion that proteins not only fold into recurring structural motifs but might also be carrying out only a limited set of recurring mobility motifs. The complete set of these patterns, which we tentatively call the dynasome, spans a multi-dimensional space with axes, the dynasome descriptors, characterizing different aspects of protein dynamics. The unique dynamic fingerprint of each protein is represented as a vector in the dynasome space. The difference between any two vectors, consequently, gives a reliable measure of the difference between the corresponding protein dynamics. We characterize the properties of the dynasome by comparing the dynamics fingerprints obtained from molecular dynamics simulations of 112 proteins but our approach is, in principle, not restricted to any specific source of data of protein dynamics. We conclude that: 1. the dynasome consists of a continuum of proteins, rather than well separated classes. 2. For the majority of proteins we observe strong correlations between structure and dynamics. 3. Proteins with similar function carry out similar dynamics, which suggests a new method to improve protein function annotation based on protein dynamics. PMID:22606222

  20. Degradation of signal to noise ratio in optical free space data links due to background illumination.

    Science.gov (United States)

    Leeb, W R

    1989-08-15

    In free space optical data transmission systems illumination of the receiver antenna by background radiation will decrease the signal to noise ratio. We derive expressions for that degradation both for direct and for heterodyne/homodyne receivers. Examples are given for cases where the sun, the moon, the earth, and Venus illuminate earth orbiting receivers operating at wavelengths of 0.85 microm, 1.3 microm, and 10.6 microm. Direct detection receivers will typically suffer a degradation of between 5 and 15 dB at lambda = 0.85 microm and lambda = 1.3 microm when illuminated by the sun. Heterodyne/homodyne receivers at 10.6 microm degrade more with sun radiation (typically 4 dB) than at the smaller wavelengths ( approximately 0.3 dB). The moon, earth, and Venus cause negligible reduction of signal to noise ratio.

  1. STRUCTURAL AND FUNCTIONAL MONITORING OF EXTRAMACULAR CYSTOID SPACES IN A CASE OF X-LINKED RETINOSCHISIS TREATED WITH ACETAZOLAMIDE.

    Science.gov (United States)

    Collison, Frederick T; Fishman, Gerald A

    2016-12-13

    Carbonic anhydrase inhibitors (CAIs) have been shown to have a beneficial effect on cystoid macular edema in X-linked retinoschisis (XLRS) and other inherited retinal conditions. The effect of CAIs outside the macula has been less well studied. Snellen visual acuity, spectral-domain optical coherence tomography (SD-OCT), kinetic visual field, and dark-adapted single-flash full-field electroretinogram (ERG) testing were all done at baseline and at least one follow-up visit. A 55-year-old male diagnosed with XLRS exhibited extensive macular and extramacular cystoid splitting in the right eye and was treated with oral extended-release acetazolamide 500 mg/day. By 6 months of follow-up on acetazolamide treatment, SD-OCT demonstrated resolution of cystoid spaces both within the macula and out to the midperiphery. Visual acuity improved from 20/70 to 20/30. The full-field ERG was distinctly electronegative at both baseline and at a follow-up visit, with oscillatory potentials becoming more apparent at the follow-up visit. Peripheral visual field boundaries did not change significantly. This report demonstrates structural resolution of cystoid spaces throughout much of the retina in a patient with XLRS, adding to a published case report in which we first noted that extramacular cystoid spaces observed in XLRS may respond to CAI treatment. To our knowledge, this is the first reported study of follow-up functional studies (ERG and perimetry) in a CAI treatment responder with XLRS.

  2. A Reemerging Political Space for Linking Person and Community Through Primary Health Care

    Science.gov (United States)

    Bazemore, Andrew; Phillips, Robert L.; Etz, Rebecca S.; Stange, Kurt C.

    2012-01-01

    Objectives. We sought to understand how national policy key informants perceive the value and changing role of primary care in the context of emerging political opportunities. Methods. We conducted 13 semistructured interviews in May 2011 with leaders of federal agencies, think tanks, nonprofits, and quality standard–defining organizations with influence over health care reform policies and implementation. We recorded the interviews and used an editing and immersion–crystallization analysis approach to identify themes. Results. We identified 4 themes: (1) affirmation of primary care as the foundation of a more effective health care system, (2) the patient-centered medical home as a transitional step to foster practice innovation and payment reform, (3) the urgent need for an increased focus on community and population health in primary care, and (4) the ongoing need for advocacy and research efforts to keep primary care on public and policy agendas. Conclusions. Current efforts to reform primary care are only intermediate steps toward a system with a greater focus on community and population health. Transformed and policy-enabled primary care is an essential link between personalized care and population health. PMID:22690969

  3. Evolution and Biogeography of Haemonchus contortus: Linking Faunal Dynamics in Space and Time.

    Science.gov (United States)

    Hoberg, E P; Zarlenga, D S

    2016-01-01

    History is the foundation that informs about the nuances of faunal assembly that are essential in understanding the dynamic nature of the host-parasite interface. All of our knowledge begins and ends with evolution, ecology and biogeography, as these interacting facets determine the history of biodiverse systems. These components, relating to Haemonchus, can inform about the complex history of geographical distribution, host association and the intricacies of host-parasite associations that are played out in physiological and behavioural processes that influence the potential for disease and our capacity for effective control in a rapidly changing world. Origins and evolutionary diversification among species of the genus Haemonchus and Haemonchus contortus occurred in a complex crucible defined by shifts in environmental structure emerging from cycles of climate change and ecological perturbation during the late Tertiary and through the Quaternary. A history of sequential host colonization associated with waves of dispersal bringing assemblages of ungulates from Eurasia into Africa and processes emerging from ecosystems in collision and faunal turnover defined the arena for radiation among 12 recognized species of Haemonchus. Among congeners, the host range for H. contortus is exceptionally broad, including species among artiodactyls of 40 genera representing 5 families (and within 12 tribes of Bovidae). Broad host range is dramatically reflected in the degree to which translocation, introduction and invasion with host switching, has characterized an expanding distribution over time in North America, South America, southern Eurasia, Australia and New Zealand, coincidental with agriculture, husbandry and global colonization by human populations driven particularly by European exploration after the 1500s. African origins in xeric to mesic habitats of the African savannah suggest that historical constraints linked to ecological adaptations (tolerances and

  4. A Study of Fog Characteristics using Free-Space Optical Wireless Links

    Directory of Open Access Journals (Sweden)

    M. S. Awan

    2010-06-01

    Full Text Available A technique for modeling the fog droplet size distributions using modified gamma distribution has been demonstrated by considering two separate radiation fog events recorded in Graz (Austria and Prague (Czech Republic. The measurement of liquid water content (LWC and the optical attenuations at visible wavelength are used to form equations to obtain the three parameters of the modified gamma distribution i.e., the slope (Λ, the intercept (N0 and the shape parameter (m. Calculated attenuation or LWC from the retrieved parameters are in excellent agreement with attenuation or LWC obtained from the measurement. Hence this method is useful in the study of fog microphysics and in modeling the fog attenuations for terrestrial FSO links in situations when our measurement data contains values of attenuations only, or liquid water content only or both at a particular location. For the two case studies, Graz and Prague, we obtained the DSD parameters Λ=3.547 ± 1.935, N0 =3.834 ± 2.239, m=6.135 ± 2.692 and Λ=5.882 ± 2.889, N0 =13.41 ± 3.875, m=5.288 ± 3.113, respectively. It is evident that the observed behavior of computed modified gamma distribution parameters for Graz and Prague is closely the same and is consistent with the previous literature for the radiation (continental fog. Moreover, we observed the variation of the computed DSD parameters at the different stages of fog (formation, maturity and dissipation phases indicating different microphysical processes at each stage.

  5. Playing Reading, Using Hands: Which Activities are Linked to Number-Space Processing in Preschool Children?

    Directory of Open Access Journals (Sweden)

    Patro Katarzyna

    2017-12-01

    Full Text Available Literate subjects from Western cultures form spatial-numerical associations (SNA in left-to-right direction, which follows their reading habits. In preliterate children, sources of SNA directionality are more disputable. One possibility is that SNA follows children's early knowledge about text orientation. It could also reflect ipsilateral/contralateral tendencies in manual task execution. Furthermore, SNA's characteristics could differ depending on the evaluation method used. In this study, we test SNA in preliterate preschoolers using object counting, finger counting, and numerosity arrangement tasks. We examined the relations of SNA to children's directional reading knowledge and their manual response tendencies. Left-to-right SNA was pronounced for object counting, disappeared for the numerosity task, and was reversed for finger counting. In all tasks, left-to-right SNA dominated in children who responded contralaterally with their hand. Reading knowledge was partially related to numerosity-based SNA, but not to other SNAs. Based on these findings, we discuss developmental characteristics of different forms of number-space associations.

  6. Dilated perivascular spaces and fatigue: is there a link? Magnetic resonance retrospective 3Tesla study

    Energy Technology Data Exchange (ETDEWEB)

    Conforti, Renata; Cirillo, Mario; Sardaro, Angela; Negro, Alberto; Cirillo, Sossio [Second University of Naples, Neuroradiology Service, Department of Radiology, Naples (Italy); Caiazzo, Giuseppina; Paccone, Antonella [Second University of Naples, MRI Research Center SUN-FISM, Naples (Italy); Sacco, Rosaria; Sparaco, Maddalena; Gallo, Antonio; Lavorgna, Luigi; Tedeschi, Gioacchino [Second University of Naples, Department of Neurology, Naples (Italy)

    2016-09-15

    Fatigue (F) is a common, inexplicable, and disabling symptom in multiple sclerosis (MS) patients. The purpose of this study was to evaluate a possible correlation between fatigue and morpho-volumetric features and site of dilated perivascular spaces (dPS), visible on 3T magnetic resonance (MR) in fatigued multiple sclerosis patients (FMS). We studied 82 relapsing remitting (RR) FMS patients and 43 HC, matched for age, sex, and education. F was assessed by the Fatigue Severity Scale (FSS). To evaluate a possible correlation between degree of F and characteristics of dPS, patients were divided in two groups: more (mFMS) (FSS ≥ 5; n = 30) and less fatigued (lFMS) (FSS ≥ 4; n = 52), compared to a matched healthy control (HC) subject group. The MR study was performed with 3T scanner by SpinEcho T1, Fast-SpinEcho DP-T2, FLAIR, and 3D FSPGR T1 sequences. dPS volumes were measured with Medical Image Processing Analysis and Visualization (MIPAV); Global Cerebral Atrophy (GCA), expressed as Brain Parenchymal Fraction (BPF), was assessed by FSL SIENAX. The t test showed significantly increased dPS number (p = 0.021) in FMS patients (mFMS p = 0.0024 and lFMS p = 0.033) compared to HC. Pearson correlation revealed a significant correlation between dPS number and FSS (r = 0.208 p = 0.051). Furthermore, the chi-squared test confirms the intragroup (HC, mFMS, lFMS) differences about dPS location (p = 0.01) and size (p = 0.0001). Our study confirms that PS in MS patients presents with different volumetric and site characteristics as compared to HC; moreover, F severity significantly correlates with dPS number, site, and size. (orig.)

  7. Linking space observations to volcano observatories in Latin America: Results from the CEOS DRM Volcano Pilot

    Science.gov (United States)

    Delgado, F.; Pritchard, M. E.; Biggs, J.; Arnold, D. W. D.; Poland, M. P.; Ebmeier, S. K.; Wauthier, C.; Wnuk, K.; Parker, A. L.; Amelug, F.; Sansosti, E.; Mothes, P. A.; Macedo, O.; Lara, L.; Zoffoli, S.; Aguilar, V.

    2015-12-01

    Within Latin American, about 315 volcanoes that have been active in the Holocene, but according to the United Nations Global Assessment of Risk 2015 report (GAR15) 202 of these volcanoes have no seismic, deformation or gas monitoring. Following the 2012 Santorini Report on satellite Earth Observation and Geohazards, the Committee on Earth Observation Satellites (CEOS) has developed a 3-year pilot project to demonstrate how satellite observations can be used to monitor large numbers of volcanoes cost-effectively, particularly in areas with scarce instrumentation and/or difficult access. The pilot aims to improve disaster risk management (DRM) by working directly with the volcano observatories that are governmentally responsible for volcano monitoring, and the project is possible thanks to data provided at no cost by international space agencies (ESA, CSA, ASI, DLR, JAXA, NASA, CNES). Here we highlight several examples of how satellite observations have been used by volcano observatories during the last 18 months to monitor volcanoes and respond to crises -- for example the 2013-2014 unrest episode at Cerro Negro/Chiles (Ecuador-Colombia border); the 2015 eruptions of Villarrica and Calbuco volcanoes, Chile; the 2013-present unrest and eruptions at Sabancaya and Ubinas volcanoes, Peru; the 2015 unrest at Guallatiri volcano, Chile; and the 2012-present rapid uplift at Cordon Caulle, Chile. Our primary tool is measurements of ground deformation made by Interferometric Synthetic Aperture Radar (InSAR) but thermal and outgassing data have been used in a few cases. InSAR data have helped to determine the alert level at these volcanoes, served as an independent check on ground sensors, guided the deployment of ground instruments, and aided situational awareness. We will describe several lessons learned about the type of data products and information that are most needed by the volcano observatories in different countries.

  8. Steering compensation for strong vertical refraction gradients in a long-distance free-space optical communication link over water

    Science.gov (United States)

    Suite, M. R.; Moore, C. I.; Burris, H. R., Jr.; Wasiczko, L.; Stell, M. F.; Rabinovich, W. S.; Scharpf, W. J.; Gilbreath, G. C.

    2005-08-01

    It is important to be able to characterize and compensate for refraction effects in free-space optical laser communication (FSO lasercom). The refractive index depends on various properties of the propagation medium such as temperature, pressure, and moisture, with temperature having the largest affect. Very strong but slow-varying thermal gradients have been observed at the NRL Chesapeake Bay lasercom testbed, which offers a 16 km one-way (32 km round-trip) FSO lasercom link over water. Thermal gradients affect the elevation-pointing angle, and their magnitudes are a function of the time of day and year and also the weather conditions. These vertical refraction errors are corrected by the use of a fiber positioner controlled by a position-sensing detector (PSD). This system is implemented into the receiver at the NRL Chesapeake Bay lasercom testbed. System test results will be presented.

  9. Crosstalk mitigation in a free-space orbital angular momentum multiplexed communication link using 4×4 MIMO equalization.

    Science.gov (United States)

    Huang, Hao; Cao, Yinwen; Xie, Guodong; Ren, Yongxiong; Yan, Yan; Bao, Changjing; Ahmed, Nisar; Neifeld, Mark A; Dolinar, Samuel J; Willner, Alan E

    2014-08-01

    We demonstrate crosstalk mitigation using 4×4 multiple-input-multiple-output (MIMO) equalization on an orbital angular momentum (OAM) multiplexed free-space data link with heterodyne detection. Four multiplexed OAM beams, each carrying a 20  Gbit/s quadrature phase-shift keying signal, propagate through weak turbulence. The turbulence induces inter-channel crosstalk among each beam and degrades the signal performance. Experimental results demonstrate that with the assistance of MIMO processing, the signal quality and the bit-error-rate (BER) performance can be improved. The power penalty can be reduced by >4  dB at a BER of 3.8×10-3.

  10. On the Performance of Adaptive Data Rate over Deep Space Ka-Bank Link: Case Study Using Kepler Data

    Science.gov (United States)

    Gao, Jay L.

    2016-01-01

    Future missions envisioned for both human and robotic exploration demand increasing communication capacity through the use of Ka-band communications. The Ka-band channel, being more sensitive to weather impairments, presents a unique trade-offs between data storage, latency, data volume and reliability. While there are many possible techniques for optimizing Ka-band operations such as adaptive modulation and coding and site-diversity, this study focus exclusively on the use of adaptive data rate (ADR) to achieve significant improvement in the data volume-availability tradeoff over a wide range of link distances for near Earth and Mars exploration. Four years of Kepler Ka-band downlink symbol signal-to-noise (SNR) data reported by the Deep Space Network were utilized to characterize the Ka-band channel statistics at each site and conduct various what-if performance analysis for different link distances. We model a notional closed-loop adaptive data rate system in which an algorithm predicts the channel condition two-way light time (TWLT) into the future using symbol SNR reported in near-real time by the ground receiver and determines the best data rate to use. Fixed and adaptive margins were used to mitigate errors in channel prediction. The performance of this closed-loop adaptive data rate approach is quantified in terms of data volume and availability and compared to the actual mission configuration and a hypothetical, optimized single rate configuration assuming full a priori channel knowledge.

  11. A Unified Performance Analysis of Free-Space Optical Links over Gamma-Gamma Turbulence Channels with Pointing Errors

    KAUST Repository

    Ansari, Imran Shafique

    2013-11-13

    In this work, we present a unified performance analysis of a free-space optical (FSO) link that accounts for pointing errors and both types of detection techniques (i.e. intensity modulation/direct detection as well as heterodyne detection). More specifically, we present unified exact closed-form expressions for the cumulative distribution function, the probability density function, the moment generating function, and the moments of the end-to-end signal-to-noise ratio (SNR) of a single link FSO transmission system, all in terms of the Meijer\\'s G function except for the moments that is in terms of simple elementary functions. We then capitalize on these unified results to offer unified exact closed-form expressions for various performance metrics of FSO link transmission systems, such as, the outage probability, the higher-order amount of fading (AF), the average error rate for binary and M-ary modulation schemes, and the ergodic capacity, all in terms of Meijer\\'s G functions except for the higher-order AF that is in terms of simple elementary functions. Additionally, we derive the asymptotic results for all the expressions derived earlier in terms of Meijer\\'s G function in the high SNR regime in terms of simple elementary functions via an asymptotic expansion of the Meijer\\'s G function. We also derive new asymptotic expressions for the ergodic capacity in the low as well as high SNR regimes in terms of simple elementary functions via utilizing moments. All the presented results are verified via computer-based Monte-Carlo simulations.

  12. Space-time trellis coding with transmit laser selection for FSO links over strong atmospheric turbulence channels.

    Science.gov (United States)

    García-Zambrana, Antonio; Castillo-Vázquez, Carmen; Castillo-Vázquez, Beatriz

    2010-03-15

    Atmospheric turbulence produces fluctuations in the irradiance of the transmitted optical beam, which is known as atmospheric scintillation, severely degrading the link performance. In this paper, a scheme combining transmit laser selection (TLS) and space-time trellis code (STTC) for multiple-input-single-output (MISO) free-space optical (FSO) communication systems with intensity modulation and direct detection (IM/DD) over strong atmospheric turbulence channels is analyzed. Assuming channel state information at the transmitter and receiver, we propose the transmit diversity technique based on the selection of two out of the available L lasers corresponding to the optical paths with greater values of scintillation to transmit the baseline STTCs designed for two transmit antennas. Based on a pairwise error probability (PEP) analysis, results in terms of bit error rate are presented when the scintillation follows negative exponential and K distributions, which cover a wide range of strong atmospheric turbulence conditions. Obtained results show a diversity order of 2L-1 when L transmit lasers are available and a simple two-state STTC with rate 1 bit/(s .Hz) is used. Simulation results are further demonstrated to confirm the analytical results.

  13. Demonstration of free-space optical communication for long-range data links between balloons on Project Loon

    Science.gov (United States)

    Moision, Bruce; Erkmen, Baris; Keyes, Edward; Belt, Todd; Bowen, Oliver; Brinkley, Devin; Csonka, Paul; Eglington, Michael; Kazmierski, Andrei; Kim, Nam-hyong; Moody, John; Tu, Thanh; Vermeer, William

    2017-02-01

    Internet connectivity is limited and in some cases non-existent for a significant part of the world's population. Project Loon aims to address this with a network of high-altitude balloons traveling in the stratosphere, at an altitude of approximately 20 km. The balloons navigate by using the stratified wind layers at different altitudes, adjusting the balloon's altitude to catch winds in a desired direction. Data transfer is achieved by 1) uplinking a signal from an Internet-connected ground station to a balloon terminal, 2) crosslinking the signal through the balloon network to reach the geographic area of the users, and 3) downlinking the signal directly to the end-users' phones or other LTE-enabled devices. We describe Loon's progress on utilizing free-space optical communications (FSOC) for the inter-balloon crosslinks. FSOC, offering high data rates and long communication ranges, is well-suited for communication between high-altitude platforms. A stratospheric link is sufficiently high to be above weather events (clouds, fog, rain, etc.), and the impact of atmospheric turbulence is significantly weaker than at ground level. In addition, being in the stratosphere as opposed to space helps avoid the typical challenges faced by space-based systems, namely operation in a vacuum environment with significant radiation. Finally, the angular pointing disturbances introduced by a floating balloon-based platform are notably less than any propelled platform, which simplifies the disturbance rejection requirements on the FSOC system. We summarize results from Project Loon's early-phase experimental inter-balloon links at 20 km altitude, demonstrating full duplex 130 Mbps throughput at distances in excess of 100 km over the course of several-day flights. The terminals utilize a monostatic design, with dual wavelengths for communication and a dedicated wide-angle beacon for pointing, acquisition, and tracking. We summarize the constraints on the terminal design, and the

  14. Linking Discourse and Space

    DEFF Research Database (Denmark)

    Richardson, Tim; Jensen, Ole B.

    2003-01-01

    The aim of the paper is to explore how spatialities are contructed in spatial policy discourses and to explore how these construction processes might be conceptualised and analysed.......The aim of the paper is to explore how spatialities are contructed in spatial policy discourses and to explore how these construction processes might be conceptualised and analysed....

  15. BILHETES DO CÁRCERE: elo entre espaçosNOTES FROM PRISON: link between spaces

    Directory of Open Access Journals (Sweden)

    Temis Gomes Parente

    2010-12-01

    The penitentiary world has been the object of a variety of studies in the most diverse areas of knowledge and still maintains itself poorly understood. This is due particularly to the barriers that are imposed to the researchers in the gaining of direct contact with prisoners and primary data sources. In this sense this work, developed during the Master dissertation studies in Environment Sciences in the Federal University of Tocantins (UFT, presents a plus in the analysis by including 960 notes written by men held in prison, in the provisory detain house of Palmas. The purpose of this article is to present an interpretation of the quotidian life in prison by means of interpretation of note readings written by the inmates. In a unique manner, we tried to understand the mechanisms used by these men to maintain a link between life in prison and the one external to it. Seen in a self perspective of writing (GOMES, 2004, the notes reveal much of the quotidian of prisoners in the house of prison: their problems, conduct, privations and anguishes. Keywords: Prisoners. Penitentiary. Spaces. Self writing.

  16. Time Synchronization and Distribution Mechanisms for Space Networks

    Science.gov (United States)

    Woo, Simon S.; Gao, Jay L.; Clare, Loren P.; Mills, David L.

    2011-01-01

    This work discusses research on the problems of synchronizing and distributing time information between spacecraft based on the Network Time Protocol (NTP), where NTP is a standard time synchronization protocol widely used in the terrestrial network. The Proximity-1 Space Link Interleaved Time Synchronization (PITS) Protocol was designed and developed for synchronizing spacecraft that are in proximity where proximity is less than 100,000 km distant. A particular application is synchronization between a Mars orbiter and rover. Lunar scenarios as well as outer-planet deep space mother-ship-probe missions may also apply. Spacecraft with more accurate time information functions as a time-server, and the other spacecraft functions as a time-client. PITS can be easily integrated and adaptable to the CCSDS Proximity-1 Space Link Protocol with minor modifications. In particular, PITS can take advantage of the timestamping strategy that underlying link layer functionality provides for accurate time offset calculation. The PITS algorithm achieves time synchronization with eight consecutive space network time packet exchanges between two spacecraft. PITS can detect and avoid possible errors from receiving duplicate and out-of-order packets by comparing with the current state variables and timestamps. Further, PITS is able to detect error events and autonomously recover from unexpected events that can possibly occur during the time synchronization and distribution process. This capability achieves an additional level of protocol protection on top of CRC or Error Correction Codes. PITS is a lightweight and efficient protocol, eliminating the needs for explicit frame sequence number and long buffer storage. The PITS protocol is capable of providing time synchronization and distribution services for a more general domain where multiple entities need to achieve time synchronization using a single point-to-point link.

  17. De Novo Mutations of RERE Cause a Genetic Syndrome with Features that Overlap Those Associated with Proximal 1p36 Deletions

    NARCIS (Netherlands)

    Fregeau, B.; Kim, B.J.; Hernandez-Garcia, A.; Jordan, V.K.; Cho, M.T.; Schnur, R.E.; Monaghan, K.G.; Juusola, J.; Rosenfeld, J.A.; Bhoj, E.; Zackai, E.H.; Sacharow, S.; Baranano, K.; Bosch, D.G.M.; Vries, B.B.A. de; Lindstrom, K.; Schroeder, A.; James, P.; Kulch, P.; Lalani, S.R.; Haelst, M.M. van; Gassen, K.L. van; Binsbergen, E. van; Barkovich, A.J.; Scott, D.A.; Sherr, E.H.

    2016-01-01

    Deletions of chromosome 1p36 affect approximately 1 in 5,000 newborns and are associated with developmental delay, intellectual disability, and defects involving the brain, eye, ear, heart, and kidney. Arginine-glutamic acid dipeptide repeats (RERE) is located in the proximal 1p36 critical region.

  18. Dependence of invadopodia function on collagen fiber spacing and cross-linking: computational modeling and experimental evidence.

    Science.gov (United States)

    Enderling, Heiko; Alexander, Nelson R; Clark, Emily S; Branch, Kevin M; Estrada, Lourdes; Crooke, Cornelia; Jourquin, Jérôme; Lobdell, Nichole; Zaman, Muhammad H; Guelcher, Scott A; Anderson, Alexander R A; Weaver, Alissa M

    2008-09-01

    Invadopodia are subcellular organelles thought to be critical for extracellular matrix (ECM) degradation and the movement of cells through tissues. Here we examine invadopodia generation, turnover, and function in relation to two structural aspects of the ECM substrates they degrade: cross-linking and fiber density. We set up a cellular automaton computational model that simulates ECM penetration and degradation by invadopodia. Experiments with denatured collagen (gelatin) were used to calibrate the model and demonstrate the inhibitory effect of ECM cross-linking on invadopodia degradation and penetration. Incorporation of dynamic invadopodia behavior into the model amplified the effect of cross-linking on ECM degradation, and was used to model feedback from the ECM. When the model was parameterized with spatial fibrillar dimensions that closely matched the organization, in real life, of native ECM collagen into triple-helical monomers, microfibrils, and macrofibrils, little or no inhibition of invadopodia penetration was observed in simulations of sparse collagen gels, no matter how high the degree of cross-linking. Experimental validation, using live-cell imaging of invadopodia in cells plated on cross-linked gelatin, was consistent with simulations in which ECM cross-linking led to higher rates of both invadopodia retraction and formation. Analyses of invadopodia function from cells plated on cross-linked gelatin and collagen gels under standard concentrations were consistent with simulation results in which sparse collagen gels provided a weak barrier to invadopodia. These results suggest that the organization of collagen, as it may occur in stroma or in vitro collagen gels, forms gaps large enough so as to have little impact on invadopodia penetration/degradation. By contrast, dense ECM, such as gelatin or possibly basement membranes, is an effective obstacle to invadopodia penetration and degradation, particularly when cross-linked. These results provide a

  19. The space - time - cube and the display of large movement data sets: the link between visualization strategies and cartographic design guidelines

    DEFF Research Database (Denmark)

    Kveladze, Irma; Kraak, Menno-Jan

    2011-01-01

    one should not only consider the nature of the data, but also the purpose of the particular phase of the workflow. To verify the above approach the visualization strategies and design guidelines are applied in a different use cases. The cases include: • The annotated space-time path A travel log...... is the Space-Time-cube (STC). The last decades the interest in this representation has increased considerable because of the technological opportunities. Despite the many domains where the STC is used, it is still unclear what the full possibilities and limitations of this graphic representation are. Its three...... consisting of a trajectory based on different modes of transport, with linked annotations. The challenge is to deal different scales and annotations. • The historical movement data The event ‘Napoleons march to Moscow’ contains fifteen space-time paths (STP) with attribute information. Challenge is to answer...

  20. Teleoperation of an experimental mobile vehicle via a free-space optical laser line-of-sight communication link for use in nuclear power plant environments

    Science.gov (United States)

    Girach, Khalid; Bouazza-Marouf, K.; Kerr, David; Hewit, Jim

    1994-11-01

    The paper describes the investigations carried out to implement a line of sight control and communication link for a mobile robot vehicle for use in structured nuclear semi-hazardous environments. Line of sight free space optical laser communication links for remote teleoperation have important applications in hazardous environments. They have certain advantages over radio/microwave links and umbilical control such as greater protection against generation of and susceptance to electro-magnetic fields. The cable-less environment provides increased integrity and mechanical freedom to the mobile robot. However, to maintain the communication link, continuous point and tracking is required between the base station and the mobile vehicle. This paper presents a novel two ended optical tracking system utilizing the communication laser beams and photodetectors. The mobile robot is a six wheel drive vehicle with a manipulator arm which can operate in a variety of terrain. The operator obtains visual feedback information from cameras placed on the vehicle. From this information, the speed and direction of the vehicle can be controlled from a joystick panel. We describe the investigations carried out for the communication of analogue video and digital data signals over the laser link for speed and direction control.

  1. Opportunities and challenges for optical wireless: the competitive advantage of free space telecommunications links in today's crowded marketplace

    Science.gov (United States)

    Carbonneau, Theresa H.; Wisely, David R.

    1998-01-01

    Never before has the opportunity for terrestrial optical wireless communications links been so great. The high data rates attainable, up to OC-24, make it a very attractive and cost effective alternative to traditional fiber optic and microwave links. With today's demand for interactive multimedia-based applications, such as video conferencing and telemedicine, optical wireless products are the only ones that can provide the needed bandwidth in situations when it is too costly or impossible to install fiber optic cable. Recent developments in laser and optics technologies, in addition to auto beam tracking, permit transmission units to achieve excellent performance rates in all weather conditions.

  2. Selection of a common communication link geometry for Saturn, Uranus and Titan. [mission planning for Pioneer and Mariner space probes

    Science.gov (United States)

    Hendricks, T.

    1974-01-01

    Mission analysis link parametrics, considering a Pioneer baseline, are developed through launch energies, flyby radii, and trip time calculations. Projected is also a 1979 Jupiter Uranus opportunity for a derivative Mariner to fly to Uranus by using the gravity field of Jupiter.

  3. Dependence of Invadopodia Function on Collagen Fiber Spacing and Cross-Linking: Computational Modeling and Experimental Evidence

    OpenAIRE

    Enderling, Heiko; Alexander, Nelson R.; Clark, Emily S.; Branch, Kevin M.; Estrada, Lourdes; Crooke, Cornelia; Jourquin, Jérôme; Lobdell, Nichole; Zaman, Muhammad H.; Guelcher, Scott A.; Anderson, Alexander R. A.; Weaver, Alissa M.

    2008-01-01

    Invadopodia are subcellular organelles thought to be critical for extracellular matrix (ECM) degradation and the movement of cells through tissues. Here we examine invadopodia generation, turnover, and function in relation to two structural aspects of the ECM substrates they degrade: cross-linking and fiber density. We set up a cellular automaton computational model that simulates ECM penetration and degradation by invadopodia. Experiments with denatured collagen (gelatin) were used to calibr...

  4. Study of the generator/motor operation of induction machines in a high frequency link space power system

    Science.gov (United States)

    Lipo, Thomas A.; Sood, Pradeep K.

    1987-01-01

    Static power conversion systems have traditionally utilized dc current or voltage source links for converting power from one ac or dc form to another since it readily achieves the temporary energy storage required to decouple the input from the output. Such links, however, result in bulky dc capacitors and/or inductors and lead to relatively high losses in the converters due to stresses on the semiconductor switches. The feasibility of utilizing a high frequency sinusoidal voltage link to accomplish the energy storage and decoupling function is examined. In particular, a type of resonant six pulse bridge interface converter is proposed which utilizes zero voltage switching principles to minimize switching losses and uses an easy to implement technique for pulse density modulation to control the amplitude, frequency, and the waveshape of the synthesized low frequency voltage or current. Adaptation of the proposed topology for power conversion to single-phase ac and dc voltage or current outputs is shown to be straight forward. The feasibility of the proposed power circuit and control technique for both active and passive loads are verified by means of simulation and experiment.

  5. Linking Venus”. New Technologies of Memory and the Reconfiguration of Space at the Warburg Library

    Directory of Open Access Journals (Sweden)

    Emanuela Patti

    2014-12-01

    Full Text Available The Hamburg art historian Aby Warburg’s (1866-1929 idea of Kulturwissenschaft lends itself to interesting reflections in the context of what, in digital humanities, we call today the technology of linking and the visualization of complex systems (Manovich 2009; Lima 2011; Manovich 2012. Numerous are the affinities between Warburg’s method of work and the visual developments of semantic web, starting from the idea of connecting discrete areas. This suggests that digital technologies could enhance the resources of the Warburg Library and iconographic database in ways that could not only reflect but also expand the original plan of his founder. This article will concern the potential reconfiguration, or “remapping”, of the Warburg’s Library resources in the digital environment and anticipates further developments. The main questions we will address are, first, how the “narrative space” of the Library can be “remediated” (Bolter/Grusin 2001 through new techniques of visualization, and, second, how Linked Data and new techniques of visualization can support, and hopefully augment, Warburg’s approach to cultural history. The article concludes with a case study, the mythological figure of Venus: its presence in the Library and iconographic classification, its potential for linking and visualizing as well as the anticipated impact of such approach on the process of knowledge production and on scholarly research. 

  6. Space Vector Modulation for DC-Link Current Ripple Reduction in Back-To-Back Current Source Converters for Microgrid Applications

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Xu, David; Guerrero, Josep M.

    2015-01-01

    Back-to-back converters have been typically used to interconnect the microgrids. For a back-to-back current source converter, the dc-link current ripple is one of the important parameters. A large ripple will cause the electromagnetic interference, undesirable high-frequency losses, and system in...... be significantly reduced by adjusting the gate patterns of space vector modulation (SVM) between the rectifier and inverter in a back-to-back converter. The experimental results verify the effectiveness of the proposed method....

  7. Experimental characterization of a 400  Gbit/s orbital angular momentum multiplexed free-space optical link over 120 m

    OpenAIRE

    Ren, Yongxiong; Wang, Zhe; Liao, Peicheng; Li, Long; Xie, Guodong; Huang, Hao; Zhao, Zhe; Yan, Yan; Ahmed, Nisar; Willner, Asher; Lavery, Martin P. J.; Ashrafi, Nima; Ashrafi, Solyman; Bock, Robert; Tur, Moshe

    2016-01-01

    We experimentally demonstrate and characterize the\\ud performance of a 400-Gbit/s orbital angular momentum\\ud (OAM) multiplexed free-space optical link over 120-\\ud meters on the roof of a building. Four OAM beams, each\\ud carrying a 100-Gbit/s QPSK channel are multiplexed and\\ud transmitted. We investigate the influence of channel\\ud impairments on the received power, inter-modal\\ud crosstalk among channels, and system power penalties.\\ud Without laser tracking and compensation systems, the\\...

  8. All-optical Ti:PPLN wavelength conversion modules for free-space optical transmission links in the mid-infrared.

    Science.gov (United States)

    Büchter, Kai-Daniel F; Herrmann, Harald; Langrock, Carsten; Fejer, Martin M; Sohler, Wolfgang

    2009-02-15

    Data-format-independent all-optical transmitter and receiver modules for free-space optical communications in the 3.8 mum region have been developed, essentially consisting of Ti-indiffused, periodically poled LiNbO(3) waveguides. Using these modules, conversion of C-band radiation to/from the mid-infrared (MIR) via difference-frequency generation was demonstrated. More than 10 mW of MIR power could be generated with the transmitter unit; the internal low-power conversion efficiency was 69%/W. A free-space MIR link was set up with a -41 dB fiber-to-fiber loss; only -15 dB are due to the parametric processes.

  9. Spaces

    Directory of Open Access Journals (Sweden)

    Maziar Nekovee

    2010-01-01

    Full Text Available Cognitive radio is being intensively researched as the enabling technology for license-exempt access to the so-called TV White Spaces (TVWS, large portions of spectrum in the UHF/VHF bands which become available on a geographical basis after digital switchover. Both in the US, and more recently, in the UK the regulators have given conditional endorsement to this new mode of access. This paper reviews the state-of-the-art in technology, regulation, and standardisation of cognitive access to TVWS. It examines the spectrum opportunity and commercial use cases associated with this form of secondary access.

  10. Possible links between extreme levels of space weather changes and human health state in middle latitudes: direct and indirect indicators

    Science.gov (United States)

    Safaraly-Oghlu Babayev, Elchin

    The Sun is the main driver of space weather. The possibility that solar activity variations and related changes in the Earth's magnetosphere can affect human life and health has been debated for many decades. This problem is being studied extensively in the late 20th and early 21st centuries and it is still being contradictory in some cases. The relations between space weather changes and the human health have global implications, but they are especially significant for habitants living at high geomagnetic latitudes where the geomagnetic disturbances have larger amplitudes. Nevertheless, the relevant researches are also important for humans living at any geomagnetic latitudes with different levels of geomagnetic activity; recent researches show that weak geomagnetic disturbances can also have adverse effects. Unfortunately, limited comparison of results of investigations on possible effects to humans from geomagnetic activity exists between studies conducted in high, middle and low latitudes. Knowledge about the relationship between solar and geomagnetic activity and the human health would allow to get better prepared beforehand for any future geomagnetic event and its impacts anywhere. For these purposes there are conducted collaborative (jointly with scientists from Israel, Bulgaria, Russia and Belgium) and cross-disciplinary space weather studies in the Azerbaijan National Academy of Sciences for revealing possible effects of solar, geomagnetic and cosmic ray variability on certain technological, biological and ecological systems in different phases of solar cycle 23. This paper describes some recently obtained results of the complex (theoretical, experimental and statistical) studies of influence of the periodical and aperiodical changes of solar, geomagnetic and cosmic ray activities upon human cardio-health state as well as human physiological and psycho-emotional state. It also covers the conclusions of studies on influence of violent solar events and severe

  11. Spatially multiplexed orbital-angular-momentum-encoded single photon and classical channels in a free-space optical communication link.

    Science.gov (United States)

    Ren, Yongxiong; Liu, Cong; Pang, Kai; Zhao, Jiapeng; Cao, Yinwen; Xie, Guodong; Li, Long; Liao, Peicheng; Zhao, Zhe; Tur, Moshe; Boyd, Robert W; Willner, Alan E

    2017-12-01

    We experimentally demonstrate spatial multiplexing of an orbital angular momentum (OAM)-encoded quantum channel and a classical Gaussian beam with a different wavelength and orthogonal polarization. Data rates as large as 100 MHz are achieved by encoding on two different OAM states by employing a combination of independently modulated laser diodes and helical phase holograms. The influence of OAM mode spacing, encoding bandwidth, and interference from the co-propagating Gaussian beam on registered photon count rates and quantum bit error rates is investigated. Our results show that the deleterious effects of intermodal crosstalk effects on system performance become less important for OAM mode spacing Δ≥2 (corresponding to a crosstalk value of less than -18.5  dB). The use of OAM domain can additionally offer at least 10.4 dB isolation besides that provided by wavelength and polarization, leading to a further suppression of interference from the classical channel.

  12. Why commercial broadband satellites absolutely must have laser intersatellite links (ISLs) and how the free-space laser communications community could let them down

    Science.gov (United States)

    Freidell, James E.

    1998-05-01

    Large commercial satellite programs needing high bandwidth inter-satellite links (ISLs) are growing rapidly in number. Precious few are visibly maturing. These commercial needs present greater customer diversity and opportunity for free- space laser communications application than the current plans of all the world's governments combined, multiplied manyfold. However, commercial customers generally do not have access to the independent, knowledgeable, but often heterogeneous laser communications expertise upon which government programs have historically relied. Moreover, commercial needs differ substantially from those of governments, particularly in the areas of price sensitivity and assured delivery on schedule and meeting all requirements. And the number of would-be laser ISL terminal suppliers also grows despite little verifiable expertise in actually delivering complete, working space-based laser ISL terminals, regardless of price or performance. Consequently, the opportunity for mistakes, disappointments, and outright failure is intensified. More 'red meatballs' are unfortunately on the horizon and neither customers nor suppliers recognize the warning signs. Is ignorance bliss? Virtually the entire space communications community appears oblivious to emerging terrestrial broadband communications projects which appear better backed with superior management far more attentive to time-to-market and other schedule and business considerations than any space venture. Space systems offer advantages through realizing global network operations not possible terrestrially, yet few promoters recogni the potential. Might these be omens worth capitalizing upon, or perhaps from which escape may be warranted? This paper provides a commercial market status update to that presented in preceding years' papers. Laser ISL applications are reviewed which enable commercial broadband satellite customer opportunities not yet recognized among most in the customer community, despite

  13. Turbulence heterodyne coherent mitigation of orbital angular momentum multiplexing in a free space optical link by auxiliary light.

    Science.gov (United States)

    Yang, Chunyong; Xu, Chuang; Ni, Wenjun; Gan, Yu; Hou, Jin; Chen, Shaoping

    2017-10-16

    A novel scheme is proposed to mitigate the atmospheric turbulence effect in free space optical (FSO) communication employing orbital angular momentum (OAM) multiplexing. In this scheme, the Gaussian beam is used as an auxiliary light with a common-path to obtain the distortion information caused by atmospheric turbulence. After turbulence, the heterodyne coherent detection technology is demonstrated to realize the turbulence mitigation. With the same turbulence distortion, the OAM beams and the Gaussian beam are respectively utilized as the signal light and the local oscillation light. Then the turbulence distortion is counteracted to a large extent. Meanwhile, a phase matching method is proposed to select the specific OAM mode. The discrimination between the neighboring OAM modes is obviously improved by detecting the output photocurrent. Moreover, two methods of beam size adjustment have been analyzed to achieve better performance for turbulence mitigation. Numerical results show that the system bit error rate (BER) can reach 10-5 under strong turbulence in simulation situation.

  14. Linking point scale process non-linearity, catchment organization and linear system dynamics in a thermodynamic state space

    Science.gov (United States)

    Zehe, Erwin; Loritz, Ralf; Ehret, Uwe; Westhoff, Martijn; Kleidon, Axel; Savenije, Hubert

    2017-04-01

    It is flabbergasting to note that catchment systems often behave almost linearly, despite of the strong non-linearity of point scale soil water characteristics. In the present study we provide evidence that a thermodynamic treatment of environmental system dynamics is the key to understand how particularly a stronger spatial organization of catchments leads to a more linear rainfall runoff behavior. Our starting point is that water fluxes in a catchment are associated with fluxes of kinetic and potential energy while changes in subsurface water stocks go along with changes in potential energy and chemical energy of subsurface water. Steady state/local equilibrium of the entire system can be defined as a state of minimum free energy, reflecting an equilibrium subsurface water storage, which is determined catchment topography, soil water characteristics and water levels in the stream. Dynamics of the entire system, i.e. deviations from equilibrium storage, are 'pseudo' oscillations in a thermodynamic state space. Either to an excess potential energy in case of wetting while subsequent relaxation back to equilibrium requires drainage/water export. Or to an excess in capillary binding energy in case of driving, while relaxation back to equilibrium requires recharge of the subsurface water stock. While system dynamics is highly non-linear on the 'too dry branch' it is essentially linear on the 'too wet branch' in case of potential energy excess. A steepened topography, which reflects a stronger spatial organization, reduces the equilibrium storage of the catchment system to smaller values, thereby it increases the range of states where the systems behaves linearly due to an excess in potential energy. Contrarily to this a shift to finer textured soils increases the equilibrium storage, which implies that the range of states where the systems behaves linearly is reduced. In this context it is important to note that an increased internal organization of the system due to

  15. Glutathione redox potential in the mitochondrial intermembrane space is linked to the cytosol and impacts the Mia40 redox state

    Science.gov (United States)

    Kojer, Kerstin; Bien, Melanie; Gangel, Heike; Morgan, Bruce; Dick, Tobias P; Riemer, Jan

    2012-01-01

    Glutathione is an important mediator and regulator of cellular redox processes. Detailed knowledge of local glutathione redox potential (EGSH) dynamics is critical to understand the network of redox processes and their influence on cellular function. Using dynamic oxidant recovery assays together with EGSH-specific fluorescent reporters, we investigate the glutathione pools of the cytosol, mitochondrial matrix and intermembrane space (IMS). We demonstrate that the glutathione pools of IMS and cytosol are dynamically interconnected via porins. In contrast, no appreciable communication was observed between the glutathione pools of the IMS and matrix. By modulating redox pathways in the cytosol and IMS, we find that the cytosolic glutathione reductase system is the major determinant of EGSH in the IMS, thus explaining a steady-state EGSH in the IMS which is similar to the cytosol. Moreover, we show that the local EGSH contributes to the partially reduced redox state of the IMS oxidoreductase Mia40 in vivo. Taken together, we provide a comprehensive mechanistic picture of the IMS redox milieu and define the redox influences on Mia40 in living cells. PMID:22705944

  16. Atmospheric turbulence mitigation in an OAM-based MIMO free-space optical link using spatial diversity combined with MIMO equalization.

    Science.gov (United States)

    Ren, Yongxiong; Wang, Zhe; Xie, Guodong; Li, Long; Willner, Asher J; Cao, Yinwen; Zhao, Zhe; Yan, Yan; Ahmed, Nisar; Ashrafi, Nima; Ashrafi, Solyman; Bock, Robert; Tur, Moshe; Willner, Alan E

    2016-06-01

    We explore the mitigation of atmospheric turbulence effects for orbital angular momentum (OAM)-based free-space optical (FSO) communications with multiple-input multiple-output (MIMO) architecture. Such a system employs multiple spatially separated aperture elements at the transmitter/receiver, and each transmitter aperture contains multiplexed data-carrying OAM beams. We propose to use spatial diversity combined with MIMO equalization to mitigate both weak and strong turbulence distortions. In a 2×2 FSO link with each transmitter aperture containing two multiplexed OAM modes of ℓ=+1 and ℓ=+3, we experimentally show that at least two OAM data channels could be recovered under both weak and strong turbulence distortions using selection diversity assisted with MIMO equalization.

  17. Experimental demonstration of bidirectional up to 40 Gbit/s QPSK coherent free-space optical communication link over ∼1 km

    Science.gov (United States)

    Feng, Xianglian; Wu, Zhihang; Wang, Tianshu; Zhang, Peng; Li, Xiaoyan; Jiang, Huilin; Su, Yuwei; He, Hongwei; Wang, Xiaoyan; Gao, Shiming

    2018-03-01

    Advanced multi-level modulation formats have shown their great potential in high-speed and high-spectral-efficiency optical communications. Using quadrature phase-shift keying (QPSK) modulation format for free-space optical (FSO) communication, a bidirectional high-speed FSO transmission link with the bit rates of up to 40 Gbit/s over ∼1 km, between two buildings in the campus of Changchun University of Science and Technology, Changchun, China, is experimentally demonstrated cooperating by capture and tracking systems. The eye-diagrams and constellation diagrams of the transmitted QPSK signals are clearly observed. By comparing the bit error rate (BER) curves before and after transmission, one can find that the receiving powers are both less than -16.5 dBm for the forward and backward transmissions of the bidirectional 20, 30, and 40 Gbit/s FSO links, and their power penalties due to the phase fluctuation of the atmospheric channel are both less than 2.6 dB, at the BER of 3.8 ×10-3.

  18. De Novo Mutations of RERE Cause a Genetic Syndrome with Features that Overlap Those Associated with Proximal 1p36 Deletions.

    Science.gov (United States)

    Fregeau, Brieana; Kim, Bum Jun; Hernández-García, Andrés; Jordan, Valerie K; Cho, Megan T; Schnur, Rhonda E; Monaghan, Kristin G; Juusola, Jane; Rosenfeld, Jill A; Bhoj, Elizabeth; Zackai, Elaine H; Sacharow, Stephanie; Barañano, Kristin; Bosch, Daniëlle G M; de Vries, Bert B A; Lindstrom, Kristin; Schroeder, Audrey; James, Philip; Kulch, Peggy; Lalani, Seema R; van Haelst, Mieke M; van Gassen, Koen L I; van Binsbergen, Ellen; Barkovich, A James; Scott, Daryl A; Sherr, Elliott H

    2016-05-05

    Deletions of chromosome 1p36 affect approximately 1 in 5,000 newborns and are associated with developmental delay, intellectual disability, and defects involving the brain, eye, ear, heart, and kidney. Arginine-glutamic acid dipeptide repeats (RERE) is located in the proximal 1p36 critical region. RERE is a widely-expressed nuclear receptor coregulator that positively regulates retinoic acid signaling. Animal models suggest that RERE deficiency might contribute to many of the structural and developmental birth defects and medical problems seen in individuals with 1p36 deletion syndrome, although human evidence supporting this role has been lacking. In this report, we describe ten individuals with intellectual disability, developmental delay, and/or autism spectrum disorder who carry rare and putatively damaging changes in RERE. In all cases in which both parental DNA samples were available, these changes were found to be de novo. Associated features that were recurrently seen in these individuals included hypotonia, seizures, behavioral problems, structural CNS anomalies, ophthalmologic anomalies, congenital heart defects, and genitourinary abnormalities. The spectrum of defects documented in these individuals is similar to that of a cohort of 31 individuals with isolated 1p36 deletions that include RERE and are recapitulated in RERE-deficient zebrafish and mice. Taken together, our findings suggest that mutations in RERE cause a genetic syndrome and that haploinsufficiency of RERE might be sufficient to cause many of the phenotypes associated with proximal 1p36 deletions. Copyright © 2016 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

  19. SAFARI digital processing unit: performance analysis of the SpaceWire links in case of a LEON3-FT based CPU

    Science.gov (United States)

    Giusi, Giovanni; Liu, Scige J.; Di Giorgio, Anna M.; Galli, Emanuele; Pezzuto, Stefano; Farina, Maria; Spinoglio, Luigi

    2014-08-01

    SAFARI (SpicA FAR infrared Instrument) is a far-infrared imaging Fourier Transform Spectrometer for the SPICA mission. The Digital Processing Unit (DPU) of the instrument implements the functions of controlling the overall instrument and implementing the science data compression and packing. The DPU design is based on the use of a LEON family processor. In SAFARI, all instrument components are connected to the central DPU via SpaceWire links. On these links science data, housekeeping and commands flows are in some cases multiplexed, therefore the interface control shall be able to cope with variable throughput needs. The effective data transfer workload can be an issue for the overall system performances and becomes a critical parameter for the on-board software design, both at application layer level and at lower, and more HW related, levels. To analyze the system behavior in presence of the expected SAFARI demanding science data flow, we carried out a series of performance tests using the standard GR-CPCI-UT699 LEON3-FT Development Board, provided by Aeroflex/Gaisler, connected to the emulator of the SAFARI science data links, in a point-to-point topology. Two different communication protocols have been used in the tests, the ECSS-E-ST-50-52C RMAP protocol and an internally defined one, the SAFARI internal data handling protocol. An incremental approach has been adopted to measure the system performances at different levels of the communication protocol complexity. In all cases the performance has been evaluated by measuring the CPU workload and the bus latencies. The tests have been executed initially in a custom low level execution environment and finally using the Real- Time Executive for Multiprocessor Systems (RTEMS), which has been selected as the operating system to be used onboard SAFARI. The preliminary results of the carried out performance analysis confirmed the possibility of using a LEON3 CPU processor in the SAFARI DPU, but pointed out, in agreement

  20. Building an Open Data Portal for the European Space Agency Climate Change Initiative based on an Iterative Development Methodology and Linked Data Technologies

    Science.gov (United States)

    Kershaw, P.; Bennett, V. L.; Stephens, A.; Wilson, A.; Waterfall, A. M.; Petrie, R.; Iwi, A.; Donegan, S.; Juckes, M. N.; Parton, G.

    2016-12-01

    The Climate Change Initiative (CCI) programme was initiated by the European Space Agency (ESA) in 2009 to address the GCOS Essential Climate Variable (ECV) requirements to provide stable, long-term, satellite-based data products to characterise the climate system and its changes. CEDA, working as part of a project consortium, were awarded the contract to build the Open Data Portal, consisting collectively of a central archive and single point of access for dissemination of the data to the international user community. Reflecting climate and earth observation community requirements, the system needed to support a range of access services in use by this domain and specifically, to integrate into existing infrastructure in the form of the Earth System Grid Federation (ESGF). This range of requirements together with the heterogeneity of the ECV datasets presented significant challenges. However, the use of Linked Data technologies and an iterative approach to data model development and data publishing have been instrumental in meeting the objectives and building a cohesive system. The portal supports data discovery based on the OGC CSW specification and on ESGF's powerful faceted search. These services provide complementary content at different levels of granularity and it therefore became clear that a common data model was needed. Key terms are defined in vocabularies serialised in SKOS and OWL and are accessible from a central vocabulary server to provide a single authoritative source for applications consuming metadata content. Exploiting the vocabulary service therefore, it has been possible to develop an innovative solution tagging ISO 19115 records for the CSW with the equivalent vocabulary terms used for the ESGF faceted search system. In this way it has been possible to create a rich user interface for the portal combining search results from both search services and the ability to dynamically populate facet selection and context-based help information from the

  1. Space space space

    CERN Document Server

    Trembach, Vera

    2014-01-01

    Space is an introduction to the mysteries of the Universe. Included are Task Cards for independent learning, Journal Word Cards for creative writing, and Hands-On Activities for reinforcing skills in Math and Language Arts. Space is a perfect introduction to further research of the Solar System.

  2. The link in Linking

    Science.gov (United States)

    Caldwell, Jane C; Chiale, Pablo A; Gonzalez, Mario D; Baranchuk, Adrian

    2013-01-01

    We present 2 cases of the slow-fast form of AVNRT with initially narrow QRS complexes followed by sudden unexpected transition to persistently wide QRS complexes due to aberrant intraventricular conduction. Introduction of a properly timed extrastimulus in one case and critical oscillations in cycle length due to short-long coupling in the second case set the stage for the initial bundle branch block. However, persistence of the aberrancy pattern once the initial event abated was maintained by the "linking" phenomenon. Delayed, retrograde concealed activation from the contralateral bundle branch perpetuated the initial bundle branch block. PMID:23840106

  3. Linked Partitions and Linked Cycles

    OpenAIRE

    Chen, William Y. C.; Wu, Susan Y. J.; Yan, Catherine H.

    2006-01-01

    The notion of noncrossing linked partition arose from the study of certain transforms in free probability theory. It is known that the number of noncrossing linked partitions of [n+1] is equal to the n-th large Schroder number $r_n$, which counts the number of Schroder paths. In this paper we give a bijective proof of this result. Then we introduce the structures of linked partitions and linked cycles. We present various combinatorial properties of noncrossing linked partitions, linked partit...

  4. Ergodic channel capacity of spatial correlated multiple-input multiple-output free space optical links using multipulse pulse-position modulation

    Science.gov (United States)

    Wang, Huiqin; Wang, Xue; Cao, Minghua

    2017-02-01

    The spatial correlation extensively exists in the multiple-input multiple-output (MIMO) free space optical (FSO) communication systems due to the channel fading and the antenna space limitation. Wilkinson's method was utilized to investigate the impact of spatial correlation on the MIMO FSO communication system employing multipulse pulse-position modulation. Simulation results show that the existence of spatial correlation reduces the ergodic channel capacity, and the reception diversity is more competent to resist this kind of performance degradation.

  5. Scandinavian links

    DEFF Research Database (Denmark)

    Matthiessen, Christian Wichmann; Knowles, Richard D.

    2014-01-01

    The European Round Table of Industrialists identified in the 1980ies 14 missing links in the transportation network of the continent. Three of them were found around the Danish island of Zealand. One link is within the nation, the other two are between nations. One link connects heavy economic....... They concentrate traffic flows and create strong transport corridors. They are the basis of new regional development regimes. “Ferries connect systems, fixed links unite systems”....

  6. Space communication link propagation data for selected cities within the multiple beam and steerable antenna coverage areas of the advanced communications technology satellite

    Science.gov (United States)

    Manning, Robert M.

    1988-01-01

    Rain attenuation propagation data for 68 cities within the coverage area of the multiple beam and steerable antennas of the Advanced Communications Technology Satellite (ACTS) are presented. These data provide the necessary data base for purposes of communication link power budgeting and rain attenuation mitigation controller design. These propagation parameters are derived by applying the ACTS Rain Attenuation Prediction Model to these 68 locations. The propagation parameters enumerated in tabular form for each location are as follows: (1) physical description of the link and location (e.g., latitude, longitude, antenna elevation angle, etc.), link availability versus attenuation margin (also in graphical form), fading time across fade depths of 3, 5, 8, and 15 dB versus fade duration, and required fade control response time for controller availabilities of 99.999, 99.99, 99.9, and 99 percent versus sub-threshold attenuation levels. The data for these specific locations can be taken to be representative of regions near these locations.

  7. Rigorous study of low-complexity adaptive space-time block-coded MIMO receivers in high-speed mode multiplexed fiber-optic transmission links using few-mode fibers

    Science.gov (United States)

    Weng, Yi; He, Xuan; Wang, Junyi; Pan, Zhongqi

    2017-01-01

    Spatial-division multiplexing (SDM) techniques have been purposed to increase the capacity of optical fiber transmission links by utilizing multicore fibers or few-mode fibers (FMF). The most challenging impairments of SDMbased long-haul optical links mainly include modal dispersion and mode-dependent loss (MDL), whereas MDL arises from inline component imperfections, and breaks modal orthogonality thus degrading the capacity of multiple-inputmultiple- output (MIMO) receivers. To reduce MDL, optical approaches include mode scramblers and specialty fiber designs, yet these methods were burdened with high cost, yet cannot completely remove the accumulated MDL in the link. Besides, space-time trellis codes (STTC) were purposed to lessen MDL, but suffered from high complexity. In this work, we investigated the performance of space-time block-coding (STBC) scheme to mitigate MDL in SDM-based optical communication by exploiting space and delay diversity, whereas weight matrices of frequency-domain equalization (FDE) were updated heuristically using decision-directed recursive-least-squares (RLS) algorithm for convergence and channel estimation. The STBC was evaluated in a six-mode multiplexed system over 30-km FMF via 6×6 MIMO FDE, with modal gain offset 3 dB, core refractive index 1.49, numerical aperture 0.5. Results show that optical-signal-to-noise ratio (OSNR) tolerance can be improved via STBC by approximately 3.1, 4.9, 7.8 dB for QPSK, 16- and 64-QAM with respective bit-error-rates (BER) and minimum-mean-square-error (MMSE). Besides, we also evaluate the complexity optimization of STBC decoding scheme with zero-forcing decision feedback (ZFDF) equalizer by shortening the coding slot length, which is robust to frequency-selective fading channels, and can be scaled up for SDM systems with more dynamic channels.

  8. Operative Links

    DEFF Research Database (Denmark)

    Wistoft, Karen; Højlund, Holger

    2012-01-01

    educational goals, learning content, or value clarification. Health pedagogy is often a matter of retrospective rationalization rather than the starting point of planning. Health and risk behaviour approaches override health educational approaches. Conclusions: Operational links between health education......, health professionalism, and management strategies pose the foremost challenge. Operational links indicates cooperative levels that facilitate a creative and innovative effort across traditional professional boundaries. It is proposed that such links are supported by network structures, shared semantics...

  9. Fault tolerance in space-based digital signal processing and switching systems: Protecting up-link processing resources, demultiplexer, demodulator, and decoder

    Science.gov (United States)

    Redinbo, Robert

    1994-01-01

    Fault tolerance features in the first three major subsystems appearing in the next generation of communications satellites are described. These satellites will contain extensive but efficient high-speed processing and switching capabilities to support the low signal strengths associated with very small aperture terminals. The terminals' numerous data channels are combined through frequency division multiplexing (FDM) on the up-links and are protected individually by forward error-correcting (FEC) binary convolutional codes. The front-end processing resources, demultiplexer, demodulators, and FEC decoders extract all data channels which are then switched individually, multiplexed, and remodulated before retransmission to earth terminals through narrow beam spot antennas. Algorithm based fault tolerance (ABFT) techniques, which relate real number parity values with data flows and operations, are used to protect the data processing operations. The additional checking features utilize resources that can be substituted for normal processing elements when resource reconfiguration is required to replace a failed unit.

  10. Space Bugz!

    DEFF Research Database (Denmark)

    Birke, Alexander; Schoenau-Fog, Henrik; Reng, Lars

    2012-01-01

    This paper presents Space Bugz! - a novel crowd game for large venues or cinemas that utilises the audience's smartphones as controllers for the game. This paper explains what crowd gaming is and describes how the approach used in Space Bugz! enables more advanced gameplay concepts and individual...... player control than current technologies allow. The gameplay of Space Bugz! is then explained along with the technical architecture of the game. After this, the iterative design process used to create the game is described together with future perspectives. The article concludes with links to a video...

  11. Space-time QAM wireless MISO systems employing differentially coded in-/out-FECC SCQICs over slow-fading Jakes scattering mobile radio links

    Directory of Open Access Journals (Sweden)

    Ardavan Rahimian

    2014-08-01

    Full Text Available This study presents research that supplements and extends the previous works on design of space-time fully systematic unpunctured (FSU serial concatenation of quadratic interleaved codes (SCQICs. The requirements for efficient design of the forward error correction (FEC codecs motivated potential information-theoretic studies for enjoying the development of low-complex system components within the FEC encoder/decoder for securing the transmission reliability. Inspired by this motivation, this study not only provides design guidelines to achieve better bit error rate performance in terms of the major design factors of FSU-SCQICs, that is, component code constraint length and trellis structure, and FEC rate, but also estimates the gain gaps of different quadratic permutation (QP structures in two crucial untouched aspects: (i signal-to-noise ratio-region comparison on the optimality and (ii investigation on the structural parameters of QPs, that is, cyclic shift and primitive factor.

  12. Disease dynamics and bird migration--linking mallards Anas platyrhynchos and subtype diversity of the influenza A virus in time and space.

    Directory of Open Access Journals (Sweden)

    Gunnar Gunnarsson

    Full Text Available The mallard Anas platyrhynchos is a reservoir species for influenza A virus in the northern hemisphere, with particularly high prevalence rates prior to as well as during its prolonged autumn migration. It has been proposed that the virus is brought from the breeding grounds and transmitted to conspecifics during subsequent staging during migration, and so a better understanding of the natal origin of staging ducks is vital to deciphering the dynamics of viral movement pathways. Ottenby is an important stopover site in southeast Sweden almost halfway downstream in the major Northwest European flyway, and is used by millions of waterfowl each year. Here, mallards were captured and sampled for influenza A virus infection, and positive samples were subtyped in order to study possible links to the natal area, which were determined by a novel approach combining banding recovery data and isotopic measurements (δ(2H of feathers grown on breeding grounds. Geographic assignments showed that the core natal areas of studied mallards were in Estonia, southern and central Finland, and northwestern Russia. This study demonstrates a clear temporal succession of latitudes of natal origin during the course of autumn migration. We also demonstrate a corresponding and concomitant shift in virus subtypes. Acknowledging that these two different patterns were based in part upon different data, a likely interpretation worth further testing is that the early arriving birds with more proximate origins have different influenza A subtypes than the more distantly originating late autumn birds. If true, this knowledge would allow novel insight into the origins and transmission of the influenza A virus among migratory hosts previously unavailable through conventional approaches.

  13. Disease dynamics and bird migration--linking mallards Anas platyrhynchos and subtype diversity of the influenza A virus in time and space.

    Science.gov (United States)

    Gunnarsson, Gunnar; Latorre-Margalef, Neus; Hobson, Keith A; Van Wilgenburg, Steven L; Elmberg, Johan; Olsen, Björn; Fouchier, Ron A M; Waldenström, Jonas

    2012-01-01

    The mallard Anas platyrhynchos is a reservoir species for influenza A virus in the northern hemisphere, with particularly high prevalence rates prior to as well as during its prolonged autumn migration. It has been proposed that the virus is brought from the breeding grounds and transmitted to conspecifics during subsequent staging during migration, and so a better understanding of the natal origin of staging ducks is vital to deciphering the dynamics of viral movement pathways. Ottenby is an important stopover site in southeast Sweden almost halfway downstream in the major Northwest European flyway, and is used by millions of waterfowl each year. Here, mallards were captured and sampled for influenza A virus infection, and positive samples were subtyped in order to study possible links to the natal area, which were determined by a novel approach combining banding recovery data and isotopic measurements (δ(2)H) of feathers grown on breeding grounds. Geographic assignments showed that the core natal areas of studied mallards were in Estonia, southern and central Finland, and northwestern Russia. This study demonstrates a clear temporal succession of latitudes of natal origin during the course of autumn migration. We also demonstrate a corresponding and concomitant shift in virus subtypes. Acknowledging that these two different patterns were based in part upon different data, a likely interpretation worth further testing is that the early arriving birds with more proximate origins have different influenza A subtypes than the more distantly originating late autumn birds. If true, this knowledge would allow novel insight into the origins and transmission of the influenza A virus among migratory hosts previously unavailable through conventional approaches.

  14. Linked data

    NARCIS (Netherlands)

    Koster, L.

    2011-01-01

    Semantisch web, linked data, web 3.0… Het zijn allemaal termen die vaak door elkaar worden gebruikt. Onterecht vindt Lukas Koster van de Universiteit van Amsterdam. Wat houden die begrippen nu eigenlijk in?

  15. Link Analysis

    Science.gov (United States)

    Donoho, Steve

    Link analysis is a collection of techniques that operate on data that can be represented as nodes and links. This chapter surveys a variety of techniques including subgraph matching, finding cliques and K-plexes, maximizing spread of influence, visualization, finding hubs and authorities, and combining with traditional techniques (classification, clustering, etc). It also surveys applications including social network analysis, viral marketing, Internet search, fraud detection, and crime prevention.

  16. Data Relay Board with Protocol for High-Speed, Free-Space Optical Communications

    Science.gov (United States)

    Wright, Malcolm; Clare, Loren; Gould, Gary; Pedyash, Maxim

    2004-01-01

    In a free-space optical communication system, the mitigation of transient outages through the incorporation of error-control methods is of particular concern, the outages being caused by scintillation fades and obscurants. The focus of this innovative technology is the development of a data relay system for a reliable high-data-rate free-spacebased optical-transport network. The data relay boards will establish the link, maintain synchronous connection, group the data into frames, and provide for automatic retransmission (ARQ) of lost or erred frames. A certain Quality of Service (QoS) can then be ensured, compatible with the required data rate. The protocol to be used by the data relay system is based on the draft CCSDS standard data-link protocol Proximity-1, selected by orbiters to multiple lander assets in the Mars network, for example. In addition to providing data-link protocol capabilities for the free-space optical link and buffering the data, the data relay system will interface directly with user applications over Gigabit Ethernet and/or with highspeed storage resources via Fibre Channel. The hardware implementation is built on a network-processor-based architecture. This technology combines the power of a hardware switch capable of data switching and packet routing at Gbps rates, with the flexibility of a software- driven processor that can host highly adaptive and reconfigurable protocols used, for example, in wireless local-area networks (LANs). The system will be implemented in a modular multi-board fashion. The main hardware elements of the data relay system are the new data relay board developed by Rockwell Scientific, a COTS Gigabit Ethernet board for user interface, and a COTS Fibre Channel board that connects to local storage. The boards reside in a cPCI back plane, and can be housed in a VME-type enclosure.

  17. A LEAFY link from outer space

    NARCIS (Netherlands)

    Scheres, B.J.G.

    1998-01-01

    The beautiful shape and colour patterns of flowers attract almost everybody, including developmental biologists. Studies of floral patterning have shown that the identity of floral organs is determined by a combinatorial code of homeotic genes, termed A, B and C, expressed in three

  18. Dancing links

    OpenAIRE

    Knuth, Donald E.

    2000-01-01

    The author presents two tricks to accelerate depth-first search algorithms for a class of combinatorial puzzle problems, such as tiling a tray by a fixed set of polyominoes. The first trick is to implement each assumption of the search with reversible local operations on doubly linked lists. By this trick, every step of the search affects the data incrementally. The second trick is to add a ghost square that represents the identity of each polyomino. Thus puts the rule that each polyomino be ...

  19. Designing New Learning Spaces

    NARCIS (Netherlands)

    Specht, Marcus

    2014-01-01

    We are moving towards new learning spaces merging the digital and the physical world. Real world objects get augmented by information streams and real world activities are measured with sensor technology to be reviewed afterwards or in real time. A variety of links is currently created to link

  20. Sex-linked recessive

    Science.gov (United States)

    Inheritance - sex-linked recessive; Genetics - sex-linked recessive; X-linked recessive ... X-linked recessive diseases most often occur in males. Males have only one X chromosome. A single recessive gene ...

  1. Sex-linked dominant

    Science.gov (United States)

    Inheritance - sex-linked dominant; Genetics - sex-linked dominant; X-linked dominant; Y-linked dominant ... can be either an autosomal chromosome or a sex chromosome. It also depends on whether the trait ...

  2. Fractal fluctuations and quantum-like chaos in the brain by analysis of variability of brain waves: A new method based on a fractal variance function and random matrix theory: A link with El Naschie fractal Cantorian space-time and V. Weiss and H. Weiss golden ratio in brain

    Energy Technology Data Exchange (ETDEWEB)

    Conte, Elio [Department of Pharmacology and Human Physiology and Tires, Center for Innovative Technologies for Signal Detection and Processing, University of Bari (Italy); School of Advanced International Studies on Theoretical and Nonlinear Methodologies-Bari (Italy)], E-mail: elio.conte@fastwebnet.it; Khrennikov, Andrei [International Center for Mathematical Modelling in Physics and Cognitive Sciences, M.S.I., University of Vaexjoe, S-35195 (Sweden); Federici, Antonio [Department of Pharmacology and Human Physiology and Tires, Center for Innovative Technologies for Signal Detection and Processing, University of Bari (Italy); Zbilut, Joseph P. [Department of Molecular Biophysics and Physiology, Rush University Medical Center, 1653W Congress, Chicago, IL 60612 (United States)

    2009-09-15

    We develop a new method for analysis of fundamental brain waves as recorded by the EEG. To this purpose we introduce a Fractal Variance Function that is based on the calculation of the variogram. The method is completed by using Random Matrix Theory. Some examples are given. We also discuss the link of such formulation with H. Weiss and V. Weiss golden ratio found in the brain, and with El Naschie fractal Cantorian space-time theory.

  3. Linked alternating forms and linked symplectic Grassmannians

    OpenAIRE

    Osserman, Brian; Bigas, Montserrat Teixidor I.

    2011-01-01

    Motivated by applications to higher-rank Brill-Noether theory and the Bertram-Feinberg-Mukai conjecture, we introduce the concepts of linked alternating and linked symplectic forms on a chain of vector bundles, and show that the linked symplectic Grassmannians parametrizing chains of subbundles isotropic for a given linked symplectic form has good dimensional behavior analogous to that of the classical symplectic Grassmannian.

  4. Space and astronomy

    CERN Document Server

    Kirkland, Kyle

    2010-01-01

    Some daring explorers like to study distant frontiers by venturing out into them, but others prefer to study them by bringing them, or representative samples, a little closer to the lab. Both options are pursued in the fields of space and astronomy. Space exploration and astronomy are intricately linked and are examined in-depth in this guide. Dedicated to the scientists who explore the frontiers of space and astronomy-and the results of their unfamiliar findings-each chapter in Space and Astronomy explores one of the frontiers of this science. The development of technology, such as rocket pro

  5. High Performance Flexible Thermal Link

    Science.gov (United States)

    Sauer, Arne; Preller, Fabian

    2014-06-01

    The paper deals with the design and performance verification of a high performance and flexible carbon fibre thermal link.Project goal was to design a space qualified thermal link combining low mass, flexibility and high thermal conductivity with new approaches regarding selected materials and processes. The idea was to combine the advantages of existing metallic links regarding flexibility and the thermal performance of high conductive carbon pitch fibres. Special focus is laid on the thermal performance improvement of matrix systems by means of nano-scaled carbon materials in order to improve the thermal performance also perpendicular to the direction of the unidirectional fibres.One of the main challenges was to establish a manufacturing process which allows handling the stiff and brittle fibres, applying the matrix and performing the implementation into an interface component using unconventional process steps like thermal bonding of fibres after metallisation.This research was funded by the German Federal Ministry for Economic Affairs and Energy (BMWi).

  6. Wallops Low Elevation Link Analysis for the Constellation Launch/Ascent Links

    Science.gov (United States)

    Cheung, Keith; Ho, C.; Kantak, A.; Lee, C.; Tye, R.; Richards, E.; Sham, C.; Schlesinger, A.; Barritt, B.

    2011-01-01

    To execute the President's Vision for Space Exploration, the Constellation Program (CxP) was formed to build the next generation spacecraft Orion and launch vehicles Ares, to transport human and cargo to International Space Station (ISS), moon, and Mars. This paper focuses on the detailed link analysis for Orion/Ares s launch and ascent links with Wallops 11.3m antenna (1) Orion's Dissimilar Voice link: 10.24 Kbps, 2-way (2) Ares Developmental Flight Instrument link, 20 Mbps, downlink. Three launch trajectories are considered: TD7-E, F (Feb), and G (Aug). In certain launch scenarios, the critical events of main engine cutoff (MECO) and Separation occur during the low elevation regime of WFF s downrange -- less than 5 degree elevation angle. The goal of the study is to access if there is enough link margins for WFF to track the DV and DFI links.

  7. Linked data management

    CERN Document Server

    Hose, Katja; Schenkel, Ralf

    2014-01-01

    Linked Data Management presents techniques for querying and managing Linked Data that is available on today’s Web. The book shows how the abundance of Linked Data can serve as fertile ground for research and commercial applications. The text focuses on aspects of managing large-scale collections of Linked Data. It offers a detailed introduction to Linked Data and related standards, including the main principles distinguishing Linked Data from standard database technology. Chapters also describe how to generate links between datasets and explain the overall architecture of data integration systems based on Linked Data. A large part of the text is devoted to query processing in different setups. After presenting methods to publish relational data as Linked Data and efficient centralized processing, the book explores lookup-based, distributed, and parallel solutions. It then addresses advanced topics, such as reasoning, and discusses work related to read-write Linked Data for system interoperation. Desp...

  8. Turbulent single-photon propagation in the Canary optical link

    Energy Technology Data Exchange (ETDEWEB)

    Capraro, Ivan; Tomaello, Andrea; Dall' Arche, Alberto; Gerlin, Francesca; Vallone, Giuseppe; Villoresi, Paolo [Department of Information Engineering, University of Padova, Padova (Italy); Herbst, Thomas [Vienna Center for Quantum Science and Technology (VCQ), Faculty of Physics, University of Vienna, Vienna (Austria); Ursin, Rupert [IQOQI - Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Vienna (Austria)

    2014-12-04

    The role of turbulence for Quantum Communications (QC) has been investigated in a 143 km-long link. The analysis of the received signal temporal domain indicate how to exploit constructively its effects in the case of QC along very long free-space links as well satellite links. Novel applications with relevant background noise may be envisaged.

  9. Linked Station Neighbors

    Data.gov (United States)

    Federal Communications Commission — This file that is a subset of the Linked-Station Set file. This file specifies, for each U.S. or impeding Canadian station part of a linked station set, the set of...

  10. Yearbook on space policy 2015 access to space and the evolution of space activities

    CERN Document Server

    Baranes, Blandina; Hulsroj, Peter; Lahcen, Arne

    2017-01-01

    The Yearbook on Space Policy, edited by the European Space Policy Institute (ESPI), is the reference publication analysing space policy developments. Each year it presents issues and trends in space policy and the space sector as a whole. Its scope is global and its perspective is European. The Yearbook also links space policy with other policy areas. It highlights specific events and issues, and provides useful insights, data and information on space activities. The first part of the Yearbook sets out a comprehensive overview of the economic, political, technological and institutional trends that have affected space activities. The second part of the Yearbook offers a more analytical perspective on the yearly ESPI theme and consists of external contributions written by professionals with diverse backgrounds and areas of expertise. The third part of the Yearbook carries forward the character of the Yearbook as an archive of space activities. The Yearbook is designed for government decision-makers and agencies...

  11. LinkED: A Novel Methodology for Publishing Linked Enterprise Data

    Directory of Open Access Journals (Sweden)

    Shreyas Suresh Rao

    2017-01-01

    Full Text Available Semantic Web technologies have redefined and strengthened the Enterprise-Web interoperability over the last decade. Linked Open Data (LOD refers to a set of best practices that empower enterprises to publish and interlink their data using existing ontologies on the World Wide Web. Current research in LOD focuses on expert search, the creation of unified information space and augmentation of core data from an enterprise context. However, existing approaches for publication of enterprise data as LOD are domain-specific, ad-hoc and suffer from lack of uniform representation across domains. The paper proposes a novel methodology called LinkED that contributes towards LOD literature in two ways: (a streamlines the publishing process through five stages of cleaning, triplification, interlinking, storage and visualization; (b addresses the latest challenges in LOD publication, namely: inadequate links, inconsistencies in the quality of the dataset and replicability of the LOD publication process. Further, the methodology is demonstrated via the publication of digital repository data as LOD in a university setting, which is evaluated based on two semantic standards: Five-Star model and data quality metrics. Overall, the paper provides a generic LOD publication process that is applicable across various domains such as healthcare, e-governance, banking, and tourism, to name a few.

  12. DIFFUSE FRONTIERS AND HALF-BREED SOCIAL ACTORS: CONCEPTUAL DEBATES AND ANALYTICAL DEVELOPMENTS REGARDING BORDERING SPACES AND THEIR LINKS TO THE WHITE INDIANS IN THE CHACO REGION DURING THE SECOND HALF OF THE XIX CENTURY

    Directory of Open Access Journals (Sweden)

    Julio César Spota

    2010-12-01

    Full Text Available In the frontier drawn between the Argentine State and the different aborigine groups of the Chaco region during the second half of the XIX century, different half-breed social identities that escape simple dichotomies between whites and Indians, civilized people and savage people were formed. The historical practice of considering social actors as white Indians (deserting soldiers, fugitive criminals, political exiles and refugees, as well as merchants who were incorporated to the Indian groups provides a privileged space for anthropological observation which has been relatively little explored until now. This paper investigates the historical reasons that motivated the migration of Creoles and recovers the perspective of social actors who took a leading role in the facts studied.

  13. Space Resources Roundtable 2

    Science.gov (United States)

    Ignatiev, A.

    2000-01-01

    Economy in CisLunar Space. Our Lunar Destiny: Creating a Lunar Economy. Cost-Effective Approaches to Lunar Passenger Transportation. Lunar Mineral Resources: Extraction and Application. Space Resources Development - The Link Between Human Exploration and the Long-term Commercialization of Space. Toward a More Comprehensive Evaluation of Space Information. Development of Metal Casting Molds by Sol-Gel Technology Using Planetary Resources. A New Concept in Planetary Exploration: ISRU with Power Bursts. Bold Space Ventures Require Fervent Public Support. Hot-pressed Iron from Lunar Soil. The Lunar Dust Problem: A Possible Remedy. Considerations on Use of Lunar Regolith in Lunar Constructions. Experimental Study on Water Production by Hydrogen Reduction of Lunar Soil Simulant in a Fixed Bed Reactor.

  14. Thermal Space in Architecture

    DEFF Research Database (Denmark)

    Petersen, Mads Dines

    Present research is revolving around the design process and the use of digital applications to support the design process among architects. This work is made in relation to the current discussions about sustainable architecture and the increased focus on energy consumption and the comfort in our...... and understanding of spaces in buildings can change significantly and instead of the creation of frozen geometrical spaces, thermal spaces can be created as it is suggested in meteorological architecture where functions are distributed in relation to temperature gradients. This creates an interesting contrast......-introducing an increased adaptability in the architecture can be a part of re-defining the environmental agenda and re-establish a link between the environment of the site and the environment of the architecture and through that an increased appreciation of the sensuous space here framed in discussions about thermal...

  15. Visualisierung von typisierten Links in Linked Data

    Directory of Open Access Journals (Sweden)

    Georg Neubauer

    2017-09-01

    Full Text Available Das Themengebiet der Arbeit behandelt Visualisierungen von typisierten Links in Linked Data. Die wissenschaftlichen Gebiete, die im Allgemeinen den Inhalt des Beitrags abgrenzen, sind das Semantic Web, das Web of Data und Informationsvisualisierung. Das Semantic Web, das von Tim Berners Lee 2001 erfunden wurde, stellt eine Erweiterung zum World Wide Web (Web 2.0 dar. Aktuelle Forschungen beziehen sich auf die Verknüpfbarkeit von Informationen im World Wide Web. Um es zu ermöglichen, solche Verbindungen wahrnehmen und verarbeiten zu können sind Visualisierungen die wichtigsten Anforderungen als Hauptteil der Datenverarbeitung. Im Zusammenhang mit dem Sematic Web werden Repräsentationen von zuhammenhängenden Informationen anhand von Graphen gehandhabt. Der Grund des Entstehens dieser Arbeit ist in erster Linie die Beschreibung der Gestaltung von Linked Data-Visualisierungskonzepten, deren Prinzipien im Rahmen einer theoretischen Annäherung eingeführt werden. Anhand des Kontexts führt eine schrittweise Erweiterung der Informationen mit dem Ziel, praktische Richtlinien anzubieten, zur Vernetzung dieser ausgearbeiteten Gestaltungsrichtlinien. Indem die Entwürfe zweier alternativer Visualisierungen einer standardisierten Webapplikation beschrieben werden, die Linked Data als Netzwerk visualisiert, konnte ein Test durchgeführt werden, der deren Kompatibilität zum Inhalt hatte. Der praktische Teil behandelt daher die Designphase, die Resultate, und zukünftige Anforderungen des Projektes, die durch die Testung ausgearbeitet wurden.

  16. Linking open vocabularies

    CERN Document Server

    Greifender, Elke; Seadle, Michael

    2013-01-01

    Linked Data (LD), Linked Open Data (LOD) and generating a web of data, present the new knowledge sharing frontier. In a philosophical context, LD is an evolving environment that reflects humankinds' desire to understand the world by drawing on the latest technologies and capabilities of the time. LD, while seemingly a new phenomenon did not emerge overnight; rather it represents the natural progression by which knowledge structures are developed, used, and shared. Linked Open Vocabularies is a significant trajectory of LD. Linked Open Vocabularies targets vocabularies that have traditionally b

  17. Sacred Space.

    Science.gov (United States)

    Adelstein, Pamela

    2018-01-01

    A space can be sacred, providing those who inhabit a particular space with sense of transcendence-being connected to something greater than oneself. The sacredness may be inherent in the space, as for a religious institution or a serene place outdoors. Alternatively, a space may be made sacred by the people within it and events that occur there. As medical providers, we have the opportunity to create sacred space in our examination rooms and with our patient interactions. This sacred space can be healing to our patients and can bring us providers opportunities for increased connection, joy, and gratitude in our daily work.

  18. Space Curves

    CERN Document Server

    Peskine, Christian; Sernesi, Edoardo

    1987-01-01

    The main topics of the conference on "Curves in Projective Space" were good and bad families of projective curves, postulation of projective space curves and classical problems in enumerative geometry.

  19. Linking to the Future

    Science.gov (United States)

    Moore, John W.

    1999-09-01

    of JCE in the mail each month, and I expect you do too. I can glance at the cover to get an overview of an issue's content, and I usually am enticed inside by intriguing cover art. I can scan the table of contents to find articles I want to read, or I can just browse through the issue to see what looks interesting. Usually the editors have juxtaposed related articles so that I often find a small treasure trove. The printed Journal is quite portable and can be read in a car or airplane. It will last a long time, and until the paper deteriorates, I will never have a problem reading back issues. I have almost every issue from the first day I subscribed and have even added some older ones from collections of retired colleagues who no longer had shelf space for them. I certainly would not want to give up my printed copies, and I want to keep getting them. I find that JCE Online provides a different kind of resource that is equally valuable. It contains more information, and information that is more appropriate in electronic form. It links related ideas into a much more complex web of information than is possible in print. And it opens pathways to lots of information that is not part of JCE but resides elsewhere. Using this issue as an example, let's take a tour of what JCE Online can do. Point your Web browser to http://jchemed.chem.wisc.edu Click on Journal and then on Current Issue (unless September 1999 is no longer the current issue, in which case you will find it in Past Issues). In the table of contents, find the article "UV Catalysis, Cyanotype Photography, and Sunscreens". Click on the title. When the abstract appears, click on Full Text (PDF) to see the article, just as it appears on page 1199 in this issue. When you are prompted, enter the name and subscriber number from your address label. At the end of the article you will find that supplementary materials are available (including a procedure for testing sunscreens) and you can click on the link to view them

  20. Space Microbiology

    OpenAIRE

    Horneck, Gerda; Klaus, David M.; Mancinelli, Rocco L

    2010-01-01

    Summary: The responses of microorganisms (viruses, bacterial cells, bacterial and fungal spores, and lichens) to selected factors of space (microgravity, galactic cosmic radiation, solar UV radiation, and space vacuum) were determined in space and laboratory simulation experiments. In general, microorganisms tend to thrive in the space flight environment in terms of enhanced growth parameters and a demonstrated ability to proliferate in the presence of normally inhibitory levels of antibiotic...

  1. Canadian space robotic activities

    Science.gov (United States)

    Sallaberger, Christian; Space Plan Task Force, Canadian Space Agency

    The Canadian Space Agency has chosen space robotics as one of its key niche areas, and is currently preparing to deliver the first flight elements for the main robotic system of the international space station. The Mobile Servicing System (MSS) is the Canadian contribution to the international space station. It consists of three main elements. The Space Station Remote Manipulator System (SSRMS) is a 7-metre, 7-dof, robotic arm. The Special Purpose Dextrous Manipulator (SPDM), a smaller 2-metre, 7-dof, robotic arm can be used independently, or attached to the end of the SSRMS. The Mobile Base System (MBS) will be used as a support platform and will also provide power and data links for both the SSRMS and the SPDM. A Space Vision System (SVS) has been tested on Shuttle flights, and is being further developed to enhance the autonomous capabilities of the MSS. The CSA also has a Strategic Technologies in Automation and Robotics Program which is developing new technologies to fulfill future robotic space mission needs. This program is currently developing in industry technological capabilities in the areas of automation of operations, autonomous robotics, vision systems, trajectory planning and object avoidance, tactile and proximity sensors, and ground control of space robots. Within the CSA, a robotic testbed and several research programs are also advancing technologies such as haptic devices, control via head-mounted displays, predictive and preview displays, and the dynamic characterization of robotic arms. Canada is also now developing its next Long Term Space Plan. In this context, a planetary exploration program is being considered, which would utilize Canadian space robotic technologies in this new arena.

  2. Let's "Downscale" Linked Data

    NARCIS (Netherlands)

    Gueret, C.D.M.; de Boer, V.; Schlobach, K.S.

    2014-01-01

    Open data policies and linked data publication are powerful tools for increasing transparency, participatory governance, and accountability. The linked data community proudly emphasizes the economic and societal impact such technology shows. But a closer look proves that the design and deployment of

  3. Let's "Downscale" Linked Data

    NARCIS (Netherlands)

    Gueret, Christophe; de Boer, Victor; Schlobach, Stefan

    2014-01-01

    Open data policies and linked data publication are powerful tools for increasing transparency, participatory governance, and accountability. A closer look at linked data technologies, however, proves that their design and deployment exclude the majority of the world’s population. It will take small

  4. Broken Links Tools

    Science.gov (United States)

    Some of these tools can be used on Drupal pages that are not published yet, or on non-Drupal content. Some, such as the Bookmarklet tools, can help make checking and correcting your links easier when used alongside Drupal's link reports.

  5. Refined Hopf Link Revisited

    CERN Document Server

    Iqbal, Amer

    2012-01-01

    We establish a relation between the refined Hopf link invariant and the S-matrix of the refined Chern-Simons theory. We show that the refined open string partition function corresponding to the Hopf link, calculated using the refined topological vertex, when expressed in the basis of Macdonald polynomials gives the S-matrix of the refined Chern-Simons theory.

  6. Koszul spaces

    DEFF Research Database (Denmark)

    Berglund, Alexander

    2014-01-01

    We prove that a nilpotent space is both formal and coformal if and only if it is rationally homotopy equivalent to the derived spatial realization of a graded commutative Koszul algebra. We call such spaces Koszul spaces and show that the rational homotopy groups and the rational homology of iter...

  7. Space administration

    OpenAIRE

    Worthington, Scott; Worthington, Scott

    2015-01-01

    My dissertation consists of two parts. The larger portion is an hour-long piece for double bass, electronics, and projected text called Space Administration. The second portion, this essay, discusses my musical background leading up to Space Administration, details of the composition itself, and what new directions I see in my work that in part stem from creating the piece Space Administration

  8. Design spaces

    DEFF Research Database (Denmark)

    2005-01-01

    Digital technologies and media are becoming increasingly embodied and entangled in the spaces and places at work and at home. However, our material environment is more than a geometric abstractions of space: it contains familiar places, social arenas for human action. For designers, the integration...... of digital technology with space poses new challenges that call for new approaches. Creative alternatives to traditional systems methodologies are called for when designers use digital media to create new possibilities for action in space. Design Spaces explores how design and media art can provide creative...... alternatives for integrating digital technology with space. Connecting practical design work with conceptual development and theorizing, art with technology, and usesr-centered methods with social sciences, Design Spaces provides a useful research paradigm for designing ubiquitous computing. This book...

  9. KLM's newest miniature house celebrates New York link

    National Research Council Canada - National Science Library

    Harriet Baskas

    2016-01-01

      KLM's newest miniature house celebrates New York link Sure, the full-flat seats, privacy screens, personal storage space, designer amenity kits, wine list and meals prepared by top Dutch chefs make...

  10. Wide Temperature DC Link Capacitors for Aerospace Power Electronics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project will develop advanced DC link capacitors using flexible ultrathin glass dielectric materials. The glass capacitor will be able to be operated in a broad...

  11. Space Psychology and Psychiatry

    Science.gov (United States)

    Kanas, N.; Manzey, D.

    2003-09-01

    This book deals with psychological, psychiatric, and psychosocial issues that affect people who live and work in space. Unlike other books that focus on anecdotal reports and ground-based simulation studies, this book emphasizes the findings from psychological research conducted during actual space missions. Both authors have been active in such research. What is presented in this readable text has previously been found only in scientific journal articles. Topics that are discussed include: behavioral adaptation to space; human performance and cognitive effects; crewmember interactions; psychiatric responses; psychological counter-measures related to habitability factors, work-design, selection, training, and in-flight monitoring and support; and the impact of expeditionary missions to Mars and beyond. People finding this book of interest will include: psychology and social science students and professors in universities; medical students and residents in psychiatry and aerospace medicine; human factors workers in space and aviation professions; individuals involved with isolated environments on Earth (e.g., the Antarctic, submarines); aerospace workers in businesses and space agencies such as NASA and ESA; and anyone who is interested in learning the facts about the human side of long-duration space missions. Link: http://www.wkap.nl/prod/b/1-4020-1341-8

  12. Observing Photons in Space

    Science.gov (United States)

    Huber, Martin C. E.; Pauluhn, Anuschka; Timothy, J. Gethyn

    This first chapter of the book "Observing Photons in Space" serves to illustrate the rewards of observing photons in space, to state our aims, and to introduce the structure and the conventions used. The title of the book reflects the history of space astronomy: it started at the high-energy end of the electromagnetic spectrum, where the photon aspect of the radiation dominates. Nevertheless, both the wave and the photon aspects of this radiation will be considered extensively. In this first chapter we describe the arduous efforts that were needed before observations from pointed, stable platforms, lifted by rocket above the Earth"s atmosphere, became the matter of course they seem to be today. This exemplifies the direct link between technical effort -- including proper design, construction, testing and calibration -- and some of the early fundamental insights gained from space observations. We further report in some detail the pioneering work of the early space astronomers, who started with the study of γ- and X-rays as well as ultraviolet photons. We also show how efforts to observe from space platforms in the visible, infrared, sub-millimetre and microwave domains developed and led to today"s emphasis on observations at long wavelengths.

  13. Link to paper

    Data.gov (United States)

    U.S. Environmental Protection Agency — Link to the paper. This dataset is associated with the following publication: Naile, J., A.W. Garrison, J. Avants, and J. Washington. Isomers/enantiomers of...

  14. Introduction to Reference Links

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Unlike most traditional metadata systems, the power of ServCat comes in relating a Reference to others. This module discusses the different types of links (aka...

  15. Link prediction on Twitter

    National Research Council Canada - National Science Library

    Sanda Martinčić-Ipšić; Edvin Močibob; Matjaž Perc

    2017-01-01

    .... Open access to information on Twitter makes it a valuable source of data for research on social interactions, sentiment analysis, content diffusion, link prediction, and the dynamics behind human...

  16. Programmable High-Rate Multi-Mission Receiver for Space Communications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Current and upcoming NASA space links require both highly reliable low-rate communications links supporting critical TT&C, ranging and voice services and highly...

  17. Linking research to practice

    DEFF Research Database (Denmark)

    Pinto-Correia, T.; Kristensen, L.

    2013-01-01

    The rural spaces in Europe are undergoing complex processes of transition, at multiple scales, and rhythms. In order to grasp and understand the changes occurring, the need emerges for new, conceptual approaches that make it possible to combine the different factors that shape spaces. Recent, lit...

  18. Problem Formulation and Analysis of the 1-Hop ARQ Links

    Science.gov (United States)

    Cheung, K.-M.

    2013-08-01

    In space communications, standard link analysis assumes that messages are sent once. For a communication link that uses an error-correction coding scheme, bit-error rate (BER) or frame-error rate (FER), and link margins are common metrics that characterize the quality of a link, and they are used to determine the supportable data rate. With the advent of Automatic Repeat-reQuest (ARQ) protocols, when messages are corrupted during transmission, they can be resent multiple times automatically until they are correctly received and acknowledged. The concept of BER, FER, and link margin cannot be directly applied, and the link analysis approach for ARQ links needs to be reexamined. In this article, we provide the problem formulation and extend the standard link analysis approach to a 1-hop ARQ link (no routing), under the assumption that code-block errors occur independently as in the case of space communications. We develop analytical models that describe the statistical behavior of standard 1-hop ARQ links. By integrating these analytical ARQ protocol models into the standard link analysis, we bypass the need to simulate or emulate the ARQ protocol operations, and generate relevant statistics on effective data rate, effective throughput, latency, and FER.

  19. Space suit

    Science.gov (United States)

    Shepard, L. F.; Durney, G. P.; Case, M. C.; Kenneway, A. J., III; Wise, R. C.; Rinehart, D.; Bessette, R. J.; Pulling, R. C. (Inventor)

    1973-01-01

    A pressure suit for high altitude flights, particularly space missions is reported. The suit is designed for astronauts in the Apollo space program and may be worn both inside and outside a space vehicle, as well as on the lunar surface. It comprises an integrated assembly of inner comfort liner, intermediate pressure garment, and outer thermal protective garment with removable helmet, and gloves. The pressure garment comprises an inner convoluted sealing bladder and outer fabric restraint to which are attached a plurality of cable restraint assemblies. It provides versitility in combination with improved sealing and increased mobility for internal pressures suitable for life support in the near vacuum of outer space.

  20. Morrey spaces

    CERN Document Server

    Adams, David R

    2015-01-01

    In this set of lecture notes, the author includes some of the latest research on the theory of Morrey Spaces associated with Harmonic Analysis. There are three main claims concerning these spaces that are covered: determining the integrability classes of the trace of Riesz potentials of an arbitrary Morrey function; determining the dimensions of singular sets of weak solutions of PDE (e.g. The Meyers-Elcart System); and determining whether there are any “full” interpolation results for linear operators between Morrey spaces. This book will serve as a useful reference to graduate students and researchers interested in Potential Theory, Harmonic Analysis, PDE, and/or Morrey Space Theory. .

  1. Space colonization

    National Research Council Canada - National Science Library

    Anita Gale; Narayanan Ramachandran

    2009-01-01

      Progress toward future space settlement is measured in small ways, mostly as incremental changes in perception and advances in targeted applied engineering that supports infrastructure development...

  2. Learning Spaces

    CERN Document Server

    Falmagne, Jean-Claude

    2011-01-01

    Learning spaces offer a rigorous mathematical foundation for practical systems of educational technology. Learning spaces generalize partially ordered sets and are special cases of knowledge spaces. The various structures are investigated from the standpoints of combinatorial properties and stochastic processes. Leaning spaces have become the essential structures to be used in assessing students' competence of various topics. A practical example is offered by ALEKS, a Web-based, artificially intelligent assessment and learning system in mathematics and other scholarly fields. At the heart of A

  3. Space psychology

    Science.gov (United States)

    Parin, V. V.; Gorbov, F. D.; Kosmolinskiy, F. P.

    1974-01-01

    Psychological selection of astronauts considers mental responses and adaptation to the following space flight stress factors: (1) confinement in a small space; (2) changes in three dimensional orientation; (3) effects of altered gravity and weightlessness; (4) decrease in afferent nerve pulses; (5) a sensation of novelty and danger; and (6) a sense of separation from earth.

  4. Borel Spaces

    CERN Document Server

    Berberian, S K

    2002-01-01

    A detailed exposition of G.W. Mackey's theory of Borel spaces (standard, substandard, analytic), based on results in Chapter 9 of Bourbaki's General Topology. Appended are five informal lectures on the subject (given at the CIMPA/ICPAM Summer School, Nice, 1986), sketching the connection between Borel spaces and representations of operator algebras.

  5. Space Telescope.

    Science.gov (United States)

    National Aeronautics and Space Administration, Huntsville, AL. George C. Marshall Space Flight Center.

    This pamphlet describes the Space Telescope, an unmanned multi-purpose telescope observatory planned for launch into orbit by the Space Shuttle in the 1980s. The unique capabilities of this telescope are detailed, the major elements of the telescope are described, and its proposed mission operations are outlined. (CS)

  6. Space microbiology.

    Science.gov (United States)

    Horneck, Gerda; Klaus, David M; Mancinelli, Rocco L

    2010-03-01

    The responses of microorganisms (viruses, bacterial cells, bacterial and fungal spores, and lichens) to selected factors of space (microgravity, galactic cosmic radiation, solar UV radiation, and space vacuum) were determined in space and laboratory simulation experiments. In general, microorganisms tend to thrive in the space flight environment in terms of enhanced growth parameters and a demonstrated ability to proliferate in the presence of normally inhibitory levels of antibiotics. The mechanisms responsible for the observed biological responses, however, are not yet fully understood. A hypothesized interaction of microgravity with radiation-induced DNA repair processes was experimentally refuted. The survival of microorganisms in outer space was investigated to tackle questions on the upper boundary of the biosphere and on the likelihood of interplanetary transport of microorganisms. It was found that extraterrestrial solar UV radiation was the most deleterious factor of space. Among all organisms tested, only lichens (Rhizocarpon geographicum and Xanthoria elegans) maintained full viability after 2 weeks in outer space, whereas all other test systems were inactivated by orders of magnitude. Using optical filters and spores of Bacillus subtilis as a biological UV dosimeter, it was found that the current ozone layer reduces the biological effectiveness of solar UV by 3 orders of magnitude. If shielded against solar UV, spores of B. subtilis were capable of surviving in space for up to 6 years, especially if embedded in clay or meteorite powder (artificial meteorites). The data support the likelihood of interplanetary transfer of microorganisms within meteorites, the so-called lithopanspermia hypothesis.

  7. grlc Makes GitHub Taste Like Linked Data APIs

    NARCIS (Netherlands)

    Merono Penuela, A.; Hoekstra, R.J.

    2016-01-01

    Building Web APIs on top of SPARQL endpoints is becoming common practice. It enables universal access to the integration favorable data space of Linked Data. In the majority of use cases, users cannot be expected to learn SPARQL to query this data space. Web APIs are the most common way to enable

  8. Space Robotics

    Directory of Open Access Journals (Sweden)

    Alex Ellery

    2004-09-01

    Full Text Available In this second of three short papers, I introduce some of the basic concepts of space robotics with an emphasis on some specific challenging areas of research that are peculiar to the application of robotics to space infrastructure development. The style of these short papers is pedagogical and the concepts in this paper are developed from fundamental manipulator robotics. This second paper considers the application of space manipulators to on-orbit servicing (OOS, an application which has considerable commercial application. I provide some background to the notion of robotic on-orbit servicing and explore how manipulator control algorithms may be modified to accommodate space manipulators which operate in the micro-gravity of space.

  9. The Rocks From Space 'Space Safari

    Science.gov (United States)

    Pearson, Victoria; Brooks, Val

    2010-05-01

    We describe an integrated online science programme incorporating Moodle virtual learning environments (VLEs) and Elluminate Live! virtual classrooms. The "Space Safari" was run as part of the Rocks From Space (RFS) programme hosted at The Open University (OU) and in partnership with Stockton City Learning Centre (SCLC). Schools used these resources for direct science teaching or to incorporate them into the wider curriculum (arts/literature etc), after which they produce an output. Emphasis was on providing links between schools and scientists within the higher education sector. Live sessions with experts via Elluminate Live! were held regularly, including sessions with NASA scientists and astronomers in Mallorca. Teachers and students have used Space Safari resources as part of the school science curriculum and to develop key skills and additional curriculum skills. They have also used it for informal (forums, online discussions) opportunities to engage with science. Over 3 years of the project, over 1500 students have engaged, with the project. The use of virtual classrooms enabled direct interaction with many students; one session alone involved over 100 students. This project is now hosted on the eTwinning portal to enable sustainability and widen access.

  10. CERN and space science

    CERN Multimedia

    2009-01-01

    The connection between CERN and space is tangible this week, as former CERN Fellow and ESA astronaut Christer Fuglesang begins the second week of his mission on space shuttle flight STS-128. I had the pleasure to meet Christer back in October 2008 at an IEEE symposium in Dresden, and he asked me whether we could give him something related to CERN for his official flight kit. We thought of caps and tee-shirts, but in the end decided to give him a neutralino as a symbol of the link between particle physics and the science of the Universe. Neutralinos are theoretical particles that the LHC will be looking for, and if they exist, they’re strong candidates for the Universe’s dark matter. Christer’s neutralino is just a model, of course, escaped from the particle zoo, but what better symbol of the connectedness of science? Christer Fuglesang is not the only link CERN has with the space shuttle programme. We’ve recently learned that...

  11. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Education Projects » Learn the Link - Drugs and HIV Learn the Link - Drugs and HIV Email Facebook Twitter ... research findings and news updates. Read on to Learn the Link between drug use and HIV and ...

  12. Knowledge spaces

    CERN Document Server

    Doignon, Jean-Paul

    1999-01-01

    Knowledge spaces offer a rigorous mathematical foundation for various practical systems of knowledge assessment. An example is offered by the ALEKS system (Assessment and LEarning in Knowledge Spaces), a software for the assessment of mathematical knowledge. From a mathematical standpoint, knowledge spaces generalize partially ordered sets. They are investigated both from a combinatorial and a stochastic viewpoint. The results are applied to real and simulated data. The book gives a systematic presentation of research and extends the results to new situations. It is of interest to mathematically oriented readers in education, computer science and combinatorics at research and graduate levels. The text contains numerous examples and exercises and an extensive bibliography.

  13. High Rate Tellecommunications for Mars Planetary and Proximity Ranges and other Deep-Space Missions-A Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Space vehicles for deep space exploration rely on microwave and millimeter wave links for communication with earth stations. As the mission of space probes expands,...

  14. Getting Sloshed in Outer Space

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 12. Getting Sloshed in Outer Space - Liquid Behavior in Microgravity. N Ananthkrishnan. General Article Volume 12 Issue 12 December 2007 pp 40-45. Fulltext. Click here to view fulltext PDF. Permanent link:

  15. enzyme-linked

    African Journals Online (AJOL)

    SA MEDIESE TYDSKRIF DEEL 63 29 JANUARIE 1983. B surface antigen in donated screening and confirmation by immunosorbent assay. Hepatitis blood - enzyme-linked. M. O. BUBB, T. ... weeks at weekly intervals. After 6 weeks test blood samples were ... This assay normally takes 3 hours. Results. Fig. 1. Frequency ...

  16. Response model parameter linking

    NARCIS (Netherlands)

    Barrett, M.L.D.

    2015-01-01

    With a few exceptions, the problem of linking item response model parameters from different item calibrations has been conceptualized as an instance of the problem of equating observed scores on different test forms. This thesis argues, however, that the use of item response models does not require

  17. Australian Curriculum Linked Lessons

    Science.gov (United States)

    Hurrell, Derek; O'Neil, Jennifer

    2011-01-01

    In providing a continued focus on tasks and activities that help to illustrate key ideas embedded in the new Australian Curriculum, this issue the authors focus, on Geometry in the Measurement and Geometry strand with strong links for an integrated focus on the Statistics and Probability strand. The small unit of work on the sorting and…

  18. Linking Literacy and Movement

    Science.gov (United States)

    Pica, Rae

    2010-01-01

    There are many links between literacy and movement. Movement and language are both forms of communication and self-expression. Rhythm is an essential component of both language and movement. While people may think of rhythm primarily in musical terms, there is a rhythm to words and sentences as well. Individuals develop an internal rhythm when…

  19. Linking place and mind

    DEFF Research Database (Denmark)

    Jensen, Marie Møller

    2016-01-01

    This paper investigates the salience of vernacular Tyneside forms on the basis of theories of enregisterment and exemplar processing. On one level, exemplar theory provides a psycholinguistic account of how the link between social value and linguistic features is possible. Conversely, integrating...

  20. TWSTFT Link Calibration Report

    Science.gov (United States)

    2015-09-01

    Washington Headquarters Services , Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302...and Bauch A (2014) THE EUROPEAN TW CALIBRATION CAMPAIGN 2014 IN THE SCOPE OF GALILEO (TGVF- FOC), An opportunity to update, TW link calibrations in

  1. Space colonization

    National Research Council Canada - National Science Library

    Ram Ramachandran; Anita Gale

    2010-01-01

    .... government trying to reinvent the human space program priorities and approaches. Russia, ESA, Japan, China, and India all have proposed ambitious missions, including manned missions, to the Moon and planets...

  2. Space exploration

    National Research Council Canada - National Science Library

    Chris Moore

    2012-01-01

      Here, Moore presents a year in review on space exploration programs. This 2012 NASA's strategy of stimulating the development of commercial capabilities to launch crew and cargo to the ISS began to pay off...

  3. SHIMMERING SPACE

    Directory of Open Access Journals (Sweden)

    Grazielle Katyane dos Santos Silva

    2009-04-01

    Full Text Available This article presents an analysis of spatiality in the book Os guarda-chuvas cintilantes (Shimmering Umbrellas, 1984, written by the Portuguese writer Teolinda Gersão. The book makes us question the journal genre. However, the text itself questions the traditional notions of narrative, which are particular to the journal genre. In Os guarda-chuvas cintilantes there is the attempt to destroy linear temporality and create a new temporal measure, based on ludic themes, is also important in the book. The configuration of spatiality crosses time, becoming, therefore, mobile and unstable. There are in the book multiples spaces: a dream space, a material space and a symbolic space.

  4. Making space

    International Development Research Centre (IDRC) Digital Library (Canada)

    Karen Kershaw

    Making space an enquiry into women's participation in local politics in Rajasthan. Alice Albin Morris, Geeta Sharma and Arun Kumar. UNNATI Organisation for Development Education. India. Parallel Sessions II - Session B ...

  5. Riesz spaces

    CERN Document Server

    Zaanen, A C

    1983-01-01

    While Volume I (by W.A.J. Luxemburg and A.C. Zaanen, NHML Volume 1, 1971) is devoted to the algebraic aspects of the theory, this volume emphasizes the analytical theory of Riesz spaces and operators between these spaces. Though the numbering of chapters continues on from the first volume, this does not imply that everything covered in Volume I is required for this volume, however the two volumes are to some extent complementary.

  6. Isolated Tracklet Linking

    Science.gov (United States)

    Weryk, Robert J.; Wainscoat, Richard J.; Williams, Gareth

    2017-10-01

    We discuss our on-going work to reduce the size of the Isolated Tracklet File (ITF) : a database hosted by the Minor Planet Center (MPC) containing 14+ million unlinked detections of asteroids. The ITF is dominated by observations from Pan-STARRS1 (F51), the Catalina Sky Survey (G96), and the Spacewatch Project (691).Survey telescopes are dependent on the follow-up capabilities of other telescopes, but many of their detected objects are not linked to already known objects, are are either not posted to the NEO Confirmation Page and/or are not followed up sufficiently, and therefore have their astrometry relegated to the ITF. While many of these asteroids may have in fact been previously observed sufficiently over longer timescales (enough to become designated objects), the linking of their astrometry can pose a challenge.We have developed a search method capable of finding and linking these isolated detections for distinct types of orbit classes, including main-belt and Hungaria objects (which often appear on the NEOCP due to their apparent motion). We use a brute-force technique which compares tracklets having motion which suggests they are the same object. Suspected linkages are further tested by searching for additional tracklets over multiple oppositions.So far, we have linked a significant portion of the ITF and have submitted these linkages to the MPC. We are confident in being able to link even more tracklets. Our method can even associate these new linkages with already designated objects, which will eventually lead to them becoming numbered objects. We hope to improve the efficiency of all asteroid surveys as future detections can be batch submitted without manual review, and more objects which are well known will not be posted to the NEOCP.

  7. Free space optical communication

    CERN Document Server

    Kaushal, Hemani; Kar, Subrat

    2017-01-01

    This book provides an in-depth understanding of free space optical (FSO) communication with a particular emphasis on optical beam propagation through atmospheric turbulence. The book is structured in such a way that it provides a basic framework for the beginners and also gives a concise description from a designer’s perspective. The book provides an exposure to FSO technology, fundamental limitations, design methodologies, system trade-offs, acquisition, tracking and pointing (ATP) techniques and link-feasibility analysis. The contents of this book will be of interest to professionals and researchers alike. The book may also be used as a textbook for engineering coursework and professional training.

  8. Brentano on Space

    Directory of Open Access Journals (Sweden)

    Leslie Kavanaugh

    2014-07-01

    Full Text Available In Vienna at the end of the nineteenth century, a virtual explosion occured of thought, creativity and revolutionary energy. At the origins of phenomenology, Franz Brentano took inspiration from Aristotle's de Anima in order to provide the bridge between mental acts [psychisch] and sensible phenomena [physisch]; the link or relationship which he called intentional in-existence. Phenomenology would completely change the direction of how philosophy constituted its problems – the relation between the “physical” and the “psychic”, the inter-relatedness of all things, the relation of our body to space and time, as well as how phenomena “appear” to consciousness. This essay briefly sketches out this geneology, and explicates the importance of Brentano's thought on the issues of space-time-continuum.

  9. Space Rescue

    Science.gov (United States)

    Muratore, John F.

    2007-01-01

    Space Rescue has been a topic of speculation for a wide community of people for decades. Astronauts, aerospace engineers, diplomats, medical and rescue professionals, inventors and science fiction writers have all speculated on this problem. Martin Caidin's 1964 novel Marooned dealt with the problems of rescuing a crew stranded in low earth orbit. Legend at the Johnson Space Center says that Caidin's portrayal of a Russian attempt to save the American crew played a pivotal role in convincing the Russians to join the real joint Apollo-Soyuz mission. Space Rescue has been a staple in science fiction television and movies portrayed in programs such as Star Trek, Stargate-SG1 and Space 1999 and movies such as Mission To Mars and Red Planet. As dramatic and as difficult as rescue appears in fictional accounts, in the real world it has even greater drama and greater difficulty. Space rescue is still in its infancy as a discipline and the purpose of this chapter is to describe the issues associated with space rescue and the work done so far in this field. For the purposes of this chapter, the term space rescue will refer to any system which allows for rescue or escape of personnel from situations which endanger human life in a spaceflight operation. This will span the period from crew ingress prior to flight through crew egress postlanding. For the purposes of this chapter, the term primary system will refer to the spacecraft system that a crew is either attempting to escape from or from which an attempt is being made to rescue the crew.

  10. public spaces

    Directory of Open Access Journals (Sweden)

    Elena Grigoryeva

    2013-01-01

    Full Text Available The topic of this issue is PUBLIC SPACES. It is familiar and clear to every citizen. The streets and courtyards as childhood experiences remain with us forever. And these are the places where we come with our parents at weekends, where we meet friends, where we have dates and where we already come for a walk with our children.The history of public spaces is long and captivating. It was the main city squares where the most important events took place in history. The Agoras of Ancient Greece and the Roman Forums, the squares of Vatican, Paris and London, Moscow and Saint Petersburg… Greve, Trafalgar, Senate, Palace, Red, Bolotnaya – behind every name there is life of capitals, countries and nations.Public spaces, their shapes, image and development greatly influence the perception of the city as a whole. Both visitors and inhabitants can see in public spaces not only the visage but the heart, the soul and the mind of the city.Unfortunately, sometimes we have to prove the value of public spaces and defend them from those who consider them nothing but a blank space, nobody’s land destined for barbarous development.What should happen to make citizens perceive public spaces as their own and to make authorities consider development and maintenance of squares and parks their priority task against the  background of increasing competition between cities and the fight for human capital? Lately they more often say about “a high-quality human capital”. And now, when they say “the city should be liveable” they add “for all groups of citizens, including the creative class”.

  11. Underground spaces/cybernetic spaces

    Directory of Open Access Journals (Sweden)

    Tomaž Novljan

    2000-01-01

    Full Text Available A modern city space is a space where in the vertical and horizontal direction dynamic, non-linear processes exist, similar as in nature. Alongside the “common” city surface, cities have underground spaces as well that are increasingly affecting the functioning of the former. It is the space of material and cybernetic communication/transport. The psychophysical specifics of using underground places have an important role in their conceptualisation. The most evident facts being their limited volume and often limited connections to the surface and increased level of potential dangers of all kinds. An efficient mode for alleviating the effects of these specific features are artistic interventions, such as: shape, colour, lighting, all applications of the basic principles of fractal theory.

  12. What is a virtual link?

    OpenAIRE

    Kuperberg, Greg

    2002-01-01

    Several authors have recently studied virtual knots and links because they admit invariants arising from R-matrices. We prove that every virtual link is uniquely represented by a link L in S X I, a thickened, compact, oriented surface S, such that the link complement (S X I) - L has no essential vertical cylinder.

  13. Bottom-linked innovation

    DEFF Research Database (Denmark)

    Kristensen, Catharina Juul

    2018-01-01

    Employee-driven innovation is gaining ground as a strategy for developing sustainable organisations in the public and private sector. This type of innovation is characterised by active employee participation, and the bottom-up perspective is often emphasised. This article explores an issue that has...... hitherto been paid little explicit attention, namely collaboration between middle managers and employees in innovation processes. In contrast to most studies, middle managers and employees are here both subjects of explicit investigation. The collaboration processes explored in this article are termed...... ‘bottom-linked innovation’. The empirical analysis is based on an in-depth qualitative study of bottom-linked innovation in a public frontline institution in Denmark. By combining research on employee-driven innovation and middle management, the article offers new insights into such collaborative...

  14. Metric spaces with unique pretangent spaces

    OpenAIRE

    Dovgoshey, Oleksiy; Abdullayev, Fahreddin; Kuchukaslan, Mehmet

    2009-01-01

    We find necessary and sufficient conditions under which an arbitrary metric space $X$ has a unique pretangent space at the marked point $a\\in X$. Key words: Metric spaces; Tangent spaces to metric spaces; Uniqueness of tangent metric spaces; Tangent space to the Cantor set.

  15. Linking assumptions in amblyopia

    Science.gov (United States)

    LEVI, DENNIS M.

    2017-01-01

    Over the last 35 years or so, there has been substantial progress in revealing and characterizing the many interesting and sometimes mysterious sensory abnormalities that accompany amblyopia. A goal of many of the studies has been to try to make the link between the sensory losses and the underlying neural losses, resulting in several hypotheses about the site, nature, and cause of amblyopia. This article reviews some of these hypotheses, and the assumptions that link the sensory losses to specific physiological alterations in the brain. Despite intensive study, it turns out to be quite difficult to make a simple linking hypothesis, at least at the level of single neurons, and the locus of the sensory loss remains elusive. It is now clear that the simplest notion—that reduced contrast sensitivity of neurons in cortical area V1 explains the reduction in contrast sensitivity—is too simplistic. Considerations of noise, noise correlations, pooling, and the weighting of information also play a critically important role in making perceptual decisions, and our current models of amblyopia do not adequately take these into account. Indeed, although the reduction of contrast sensitivity is generally considered to reflect “early” neural changes, it seems plausible that it reflects changes at many stages of visual processing. PMID:23879956

  16. Overseas links as export conduits

    OpenAIRE

    Hanley, Aoife

    2009-01-01

    This paper investigates the relationship between exports and overseas links using data from the UK Community Innovation Survey. Overseas vertical and horizontal links are associated with an average increase in export intensity of 74 and 156 percent for vertical and horizontal overseas links respectively. Firm size shows no significant interactions with overseas links. The data suggests that overseas links are a relatively infrequent form of conducting trade. My findings support the role of Go...

  17. Space Robotics

    Directory of Open Access Journals (Sweden)

    Alex Ellery

    2004-06-01

    Full Text Available In this first of three short papers, I introduce some of the basic concepts of space engineering with an emphasis on some specific challenging areas of research that are peculiar to the application of robotics to space development and exploration. The style of these short papers is pedagogical and this paper stresses the unique constraints that space application imposes. This first paper is thus a general introduction to the nature of spacecraft engineering and its application to robotic spacecraft. I consider the constraints and metrics used by spacecraft engineers in the design of spacecraft and how these constraints impose challenges to the roboticist. The following two papers consider specific robotics issues in more detail.

  18. Environmental spaces

    DEFF Research Database (Denmark)

    Larsen, Henrik Gutzon

    Using the development of intergovernmental environmental cooperation in the Baltic Sea area as a concrete example, the aim of this study is to explore how the 'environment' in situations of environmental interdependence is identified and institutionalised as political-geographical objects....... 'Environmental interdependence' is to this end conceptualised as a tension between 'political spaces' of discrete state territories and 'environmental spaces' of spatially nested ecosystems. This tension between geographies of political separateness and environmental wholeness is the implicit or explicit basis...... for a large and varied literature. But in both its critical and problemsolving manifestations, this literature tends to naturalise the spatiality of environmental concerns: environmental spaces are generally taken for granted. On the suggestion that there is a subtle politics to the specification...

  19. Tsirelson's space

    CERN Document Server

    Casazza, Peter G

    1989-01-01

    This monograph provides a structure theory for the increasingly important Banach space discovered by B.S. Tsirelson. The basic construction should be accessible to graduate students of functional analysis with a knowledge of the theory of Schauder bases, while topics of a more advanced nature are presented for the specialist. Bounded linear operators are studied through the use of finite-dimensional decompositions, and complemented subspaces are studied at length. A myriad of variant constructions are presented and explored, while open questions are broached in almost every chapter. Two appendices are attached: one dealing with a computer program which computes norms of finitely-supported vectors, while the other surveys recent work on weak Hilbert spaces (where a Tsirelson-type space provides an example).

  20. Space Telescopes

    Science.gov (United States)

    Rigby, Jane R.

    2011-01-01

    The science of astronomy depends on modern-day temples called telescopes. Astronomers make pilgrimages to remote mountaintops where these large, intricate, precise machines gather light that rains down from the Universe. Bit, since Earth is a bright, turbulent planet, our finest telescopes are those that have been launched into the dark stillness of space. These space telescopes, named after heroes of astronomy (Hubble, Chandra, Spitzer, Herschel), are some of the best ideas our species has ever had. They show us, over 13 billion years of cosmic history, how galaxies and quasars evolve. They study planets orbiting other stars. They've helped us determine that 95% of the Universe is of unknown composition. In short, they tell us about our place in the Universe. The next step in this journey is the James Webb Space Telescope, being built by NASA, Europe, and Canada for a 2018 launch; Webb will reveal the first galaxies that ever formed.

  1. STS-97 Onboard Photograph - International Space Station

    Science.gov (United States)

    2000-01-01

    This image of the International Space Station in orbit was taken from the Space Shuttle Endeavour prior to docking. Most of the Station's components are clearly visible in this photograph. They are the Node 1 or Unity Module docked with the Functional Cargo Block or Zarya (top) that is linked to the Zvezda Service Module. The Soyuz spacecraft is at the bottom.

  2. Einstein spaces

    CERN Document Server

    Petrov, Aleksej Z

    1969-01-01

    Einstein Spaces presents the mathematical basis of the theory of gravitation and discusses the various spaces that form the basis of the theory of relativity. This book examines the contemporary development of the theory of relativity, leading to the study of such problems as gravitational radiation, the interaction of fields, and the behavior of elementary particles in a gravitational field. Organized into nine chapters, this book starts with an overview of the principles of the special theory of relativity, with emphasis on the mathematical aspects. This text then discusses the need for a ge

  3. Performative Spaces

    DEFF Research Database (Denmark)

    Svaneklink, Annette

    2009-01-01

    that can be related to traditional architectural concepts in terms of dealing with space, body, time and movement. The paper considers this performativity and dual spatiality as being a processual architecture, constantly reconfiguring new hybrids between space, image and user. This dual spatiality raises......Performative aspects of architecture seem to be constituted as a series of actions between place and non-place as well as between place and user. The performative action raises a dual spatiality that relates physical, extended spatiality to temporality. The paper argues that this is a topic...

  4. Game Spaces

    DEFF Research Database (Denmark)

    Kristiansen, Erik

    2015-01-01

    or she suddenly finds himself in another world, where artefacts are given new meaning and where other rules apply. This makes sense, but also demands that play and non-play can be easily separated. Even so, the concept of the magic circle has never been analysed with respect to the spatial configuration......, called “pervasive games.” These are games that are based on computer technology, but use a physical space as the game space as opposed to video games. Coupling spatial configuration with performance theory of rituals as liminal phenomena, I put forward a model and a new understanding of the magic circle...

  5. Entering Space

    Science.gov (United States)

    Zubrin, Robert

    The authors is giving a classification of civilisations depending on the degree of colonisation of the Earth, Solar System and Our Galaxy. The problems of: History of geographic discoveries (The great geographical discoveries during the Middle Age, the concurence of Chinnese and Europeans in this Area); The Astrophysics, such as: Asteroids, Water and Atmosphere on outer planets, Planet Mars Planet, Agriculture on outer planets, Minerals on outer planets; Cosmic flights: Fuels, Robotics, Moon (as an intermediary basis for interplanetary flights), Mars colonisation; Interstellar flights, Space research costs, strategy and tactics of the space colonisation; Policy: War and Peace, International Collaboration are discussed.

  6. Transit space

    DEFF Research Database (Denmark)

    Raahauge, Kirsten Marie

    2008-01-01

    This article deals with representations of one specific city, Århus, Denmark, especially its central district. The analysis is based on anthropological fieldwork conducted in Skåde Bakker and Fedet, two well-off neighborhoods. The overall purpose of the project is to study perceptions of space...... and the interaction of cultural, social, and spatial organizations, as seen from the point of view of people living in Skåde Bakker and Fedet. The focus is on the city dwellers’ representations of the central district of Århus with specific reference to the concept of transit space. When applied to various Århusian...

  7. Evaluation of FSO Link Using Array of Photodetectors

    Science.gov (United States)

    Singh, Mehtab

    2017-08-01

    In recent years, free-space optics (FSO) communication links have gained importance due to the availability of high data transmission rates and channel bandwidth. Although FSO links have many advantages, it also suffers from many limitations, which degrade the performance of the communication link. In this paper, the performance of an FSO link has been evaluated under fog weather condition as it severely degrades the quality of the received signal. One of the most important techniques to improve the quality of received signal in an FSO link is by using an array of photodetectors at the receiver end. In this paper, the performance evaluation of an FSO link has been performed using an array of photodetectors at the receiver end using OPTISYSTEM simulation software. The performance has been analyzed by evaluating Q-factor, bit error rate (BER), and signal-to-noise ratio (SNR) of the received signal.

  8. Trading Spaces

    Science.gov (United States)

    Cort, Cliff

    2006-01-01

    Education administrators face the dual dilemma of crowded, aging facilities and tightening capital budgets. The challenge is to build the necessary classroom, laboratory and activity space while minimizing the length and expense of the construction process. One solution that offers an affordable alternative is modular construction, a method that…

  9. Space Conquest

    CERN Multimedia

    2005-01-01

    An old water tank from the time of the ISR is being converted into a temporary store for ATLAS muon chambers. This is the last chapter in the big programme by the PH Department to make better use of space at CERN.

  10. Linking Wayfinding and Wayfaring

    DEFF Research Database (Denmark)

    Lanng, Ditte Bendix; Jensen, Ole B.

    2016-01-01

    In this chapter we propose to expand and enhance the understanding of wayfi nding beyond the strictly “instrumental” (i.e., getting from point A to point B), to include the qualities and multi-sensorial inputs that inform and shape people’s movement through space. We take as a point of departure...... of environmental information , which includes the embodied, multi-sensorial experience of moving through physical space. We base our examination in part on the classic positions of the wayfi nding literature—for example, Lynch’s seminal study, The Image of the City ( 1960 ). However, we also examine the so...... and wayfaring. Then we explore the concept of wayfaring (Ingold 2007 , 2011 ) as a key to understand embodied, multi-sensorial qualities of movement. We conclude by discussing the implications of a wayfaring perspective on wayfi nding research, design, and policy making....

  11. LinkEdu

    OpenAIRE

    Gómez Dios, Albert

    2015-01-01

    The aim is to develop an application LinkEdu that will keep families connected schools. To carry out this project first developed a web application where www.linkedu.tk have access to the schools and teachers and where they can keep data centers, courses, subjects and other important data the students of school. Furthermore develops a mobile applications messaging standards that allow communication with a particular tutor his son. L'objectiu d'aquest projecte és el desenvolupament d'una ap...

  12. EEE Links. Volume 5

    Science.gov (United States)

    Humphrey, Robert (Editor)

    1999-01-01

    The EEE Links Newsletter is a quarterly publication produced by Code 562 in support of the NASA HQ funded NASA Electronic Parts and Packaging (NEPP) Program. The newsletter is produced as an electronic format deliverable made available via the referenced www site administered by Code 562, The newsletter publishes brief articles on topics of interest to NASA programs and projects in the area of electronic parts and packaging. The newsletter does not provide information pertaining to patented or proprietary information. The information provided is at the level of that produced by industry and university researchers and is published at national and international conferences.

  13. Linking consumer experiences

    DEFF Research Database (Denmark)

    Smed, Karina Madsen

    Consumers consume products in various ways serving a number of purposes. Much attention has been paid to experiences attached to consumption, sometimes very explicitly, e.g. in tourism, the essence of which is experiences of various sorts, but often also implicitly as internalised experiences...... become part of the individual self, worldview, and behaviour. This paper seeks to explore links between consumer experiences through the exploration of narrative sequences in travel blogs. Findings indicate that non-consumption is a central element to the bloggers and also indicative of a community...

  14. Knots and links

    CERN Document Server

    Rolfsen, Dale

    2003-01-01

    Rolfsen's beautiful book on knots and links can be read by anyone, from beginner to expert, who wants to learn about knot theory. Beginners with a basic background find an inviting introduction to the elements of topology, emphasizing the tools needed for understanding knots, the fundamental group and van Kampen's theorem, for example, which are then applied to concrete problems, such as computing knot groups. For experts, Rolfsen explains advanced topics, such as the connections between knot theory and surgery and how they are useful to understanding three-manifolds. Besides providing a guide

  15. Atomic clock ensemble in space

    Science.gov (United States)

    Cacciapuoti, L.; Salomon, C.

    2011-12-01

    Atomic Clock Ensemble in Space (ACES) is a mission using high-performance clocks and links to test fundamental laws of physics in space. Operated in the microgravity environment of the International Space Station, the ACES clocks, PHARAO and SHM, will generate a frequency reference reaching instability and inaccuracy at the 1 · 10-16 level. A link in the microwave domain (MWL) and an optical link (ELT) will make the ACES clock signal available to ground laboratories equipped with atomic clocks. Space-to-ground and ground-to-ground comparisons of atomic frequency standards will be used to test Einstein's theory of general relativity including a precision measurement of the gravitational red-shift, a search for time variations of fundamental constants, and Lorentz Invariance tests. Applications in geodesy, optical time transfer, and ranging will also be supported. ACES has now reached an advanced technology maturity, with engineering models completed and successfully tested and flight hardware under development. This paper presents the ACES mission concept and the status of its main instruments.

  16. Hybrid Ground Station Technology for RF and Optical Communication Links

    Science.gov (United States)

    Davarian, Faramaz; Hoppe, D.; Charles, J.; Vilnrotter, V.; Sehic, A.; Hanson, T.; Gam, E.

    2012-01-01

    To support future enhancements of NASA's deep space and planetary communications and tracking services, the Jet Propulsion Laboratory is developing a hybrid ground station that will be capable of simultaneously supporting RF and optical communications. The main reason for adding optical links to the existing RF links is to significantly increase the capacity of deep space communications in support of future solar system exploration. It is envisioned that a mission employing an optical link will also use an RF link for telemetry and emergency purposes, hence the need for a hybrid ground station. A hybrid station may also reduce operations cost by requiring fewer staff than would be required to operate two stations. A number of approaches and techniques have been examined. The most promising ones have been prototyped for field examination and validation.

  17. Adaptive laser link reconfiguration using constraint propagation

    Science.gov (United States)

    Crone, M. S.; Julich, P. M.; Cook, L. M.

    1993-01-01

    This paper describes Harris AI research performed on the Adaptive Link Reconfiguration (ALR) study for Rome Lab, and focuses on the application of constraint propagation to the problem of link reconfiguration for the proposed space based Strategic Defense System (SDS) Brilliant Pebbles (BP) communications system. According to the concept of operations at the time of the study, laser communications will exist between BP's and to ground entry points. Long-term links typical of RF transmission will not exist. This study addressed an initial implementation of BP's based on the Global Protection Against Limited Strikes (GPALS) SDI mission. The number of satellites and rings studied was representative of this problem. An orbital dynamics program was used to generate line-of-site data for the modeled architecture. This was input into a discrete event simulation implemented in the Harris developed COnstraint Propagation Expert System (COPES) Shell, developed initially on the Rome Lab BM/C3 study. Using a model of the network and several heuristics, the COPES shell was used to develop the Heuristic Adaptive Link Ordering (HALO) Algorithm to rank and order potential laser links according to probability of communication. A reduced set of links based on this ranking would then be used by a routing algorithm to select the next hop. This paper includes an overview of Constraint Propagation as an Artificial Intelligence technique and its embodiment in the COPES shell. It describes the design and implementation of both the simulation of the GPALS BP network and the HALO algorithm in COPES. This is described using a 59 Data Flow Diagram, State Transition Diagrams, and Structured English PDL. It describes a laser communications model and the heuristics involved in rank-ordering the potential communication links. The generation of simulation data is described along with its interface via COPES to the Harris developed View Net graphical tool for visual analysis of communications

  18. Space Toxicology

    Science.gov (United States)

    James, John T.

    2011-01-01

    Safe breathing air for space faring crews is essential whether they are inside an Extravehicular Mobility Suit (EMU), a small capsule such as Soyuz, or the expansive International Space Station (ISS). Sources of air pollution can include entry of propellants, excess offgassing from polymeric materials, leakage of systems compounds, escape of payload compounds, over-use of utility compounds, microbial metabolism, and human metabolism. The toxicological risk posed by a compound is comprised of the probability of escaping to cause air pollution and the magnitude of adverse effects on human health if escape occurs. The risk from highly toxic compounds is controlled by requiring multiple levels of containment to greatly reduce the probability of escape; whereas compounds that are virtually non-toxic may require little or no containment. The potential for toxicity is determined by the inherent toxicity of the compound and the amount that could potentially escape into the breathing air.

  19. Communication spaces.

    Science.gov (United States)

    Coiera, Enrico

    2014-01-01

    Annotations to physical workspaces such as signs and notes are ubiquitous. When densely annotated, work areas become communication spaces. This study aims to characterize the types and purpose of such annotations. A qualitative observational study was undertaken in two wards and the radiology department of a 440-bed metropolitan teaching hospital. Images were purposefully sampled; 39 were analyzed after excluding inferior images. Annotation functions included signaling identity, location, capability, status, availability, and operation. They encoded data, rules or procedural descriptions. Most aggregated into groups that either created a workflow by referencing each other, supported a common workflow without reference to each other, or were heterogeneous, referring to many workflows. Higher-level assemblies of such groupings were also observed. Annotations make visible the gap between work done and the capability of a space to support work. Annotations are repairs of an environment, improving fitness for purpose, fixing inadequacy in design, or meeting emergent needs. Annotations thus record the missing information needed to undertake tasks, typically added post-implemented. Measuring annotation levels post-implementation could help assess the fit of technology to task. Physical and digital spaces could meet broader user needs by formally supporting user customization, 'programming through annotation'. Augmented reality systems could also directly support annotation, addressing existing information gaps, and enhancing work with context sensitive annotation. Communication spaces offer a model of how work unfolds. Annotations make visible local adaptation that makes technology fit for purpose post-implementation and suggest an important role for annotatable information systems and digital augmentation of the physical environment.

  20. Space Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Corliss, William R.

    1968-01-01

    This booklet discusses three kinds of space radiation, cosmic rays, Van Allen Belts, and solar plasma. Cosmic rays are penetrating particles that we cannot see, hear or feel, which come from distant stars. Van Allen Belts, named after their discoverer are great belts of protons and electrons that the earth has captured in its magnetic trap. Solar plasma is a gaseous, electrically neutral mixture of positive and negative ions that the sun spews out from convulsed regions on its surface.

  1. Integrated magnetics design for HF-link power converters

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2005-01-01

    This paper deals with the design of integrated magnetics for HF-link converters, where the integrated magnetic components do not necessarily belong to the same voltage loop. Depending on the specific HF-link converter topology, the proposed integrated magnetics can either alleviate the derivation...... of independent auxiliary supply voltages from the main transformer or integrate other magnetic structures, thus saving board space and cutting costs....

  2. Integrated magnetics design for HF-link power converters

    Energy Technology Data Exchange (ETDEWEB)

    Ljusev, P.; Andersen, Michael A.E.

    2005-07-01

    This paper deals with the design of integrated magnetics for HF-link converters, where the two integrated magnetic components on the same core do not necessarily belong to the same voltage loop. Depending on the specific HF-link converter topology, the proposed integrated magnetics can either alleviate the derivation of independent auxiliary supply voltages from the main transformer or integrate other magnetic structures, thus saving board space and cutting costs. (au)

  3. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... the Link - Drugs and HIV Learn the Link - Drugs and HIV Email Facebook Twitter 2005 –Ongoing Behaviors ... GA: CDC, DHHS. Retrieved June 2012 How are Drug Abuse and HIV Related? Drug abuse and addiction ...

  4. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... the Link - Drugs and HIV Learn the Link - Drugs and HIV Email Facebook Twitter 2005 –Ongoing Behaviors ... GA: CDC, DHHS. Retrieved November 2017. How are Drug Misuse and HIV Related? Drug misuse and addiction ...

  5. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Misuse and HIV Related? Drug misuse and addiction have been linked with HIV/AIDS since the beginning ... the link between drug misuse and HIV. We have produced a set of multicultural public service announcements ( ...

  6. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... and the disease it causes (AIDS) are often linked and referred to as "HIV/AIDS." HIV can ... HIV Related? Drug misuse and addiction have been linked with HIV/AIDS since the beginning of the ...

  7. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... the link between drug abuse and HIV infection. It contains information for young people, parents and teachers, ... present time. The virus (HIV) and the disease it causes (AIDS) are often linked and referred to ...

  8. Drugs + HIV, Learn the Link

    Medline Plus

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  15. Space Nutrition

    Science.gov (United States)

    Smith, Scott M.

    2009-01-01

    Optimal nutrition will be critical for crew members who embark on space exploration missions. Nutritional assessment provides an opportunity to ensure that crewmembers begin their missions in optimal nutritional status, to document changes during a mission and, if necessary, to provide intervention to maintain that status throughout the mission, and to assesses changes after landing in order to facilitate the return to their normal status as soon as possible after landing. We report here the findings from our nutritional assessment of astronauts who participated in the International Space Station (ISS) missions, along with flight and ground-based research findings. We also present ongoing and planned nutrition research activities. These studies provide evidence that bone loss, compromised vitamin status, and oxidative damage are the critical nutritional concerns for space travelers. Other nutrient issues exist, including concerns about the stability of nutrients in the food system, which are exposed to longterm storage and radiation during flight. Defining nutrient requirements, and being able to provide and maintain those nutrients on exploration missions, will be critical for maintaining crew member health.

  16. Space race functional responses.

    Science.gov (United States)

    Sjödin, Henrik; Brännström, Åke; Englund, Göran

    2015-02-22

    We derive functional responses under the assumption that predators and prey are engaged in a space race in which prey avoid patches with many predators and predators avoid patches with few or no prey. The resulting functional response models have a simple structure and include functions describing how the emigration of prey and predators depend on interspecific densities. As such, they provide a link between dispersal behaviours and community dynamics. The derived functional response is general but is here modelled in accordance with empirically documented emigration responses. We find that the prey emigration response to predators has stabilizing effects similar to that of the DeAngelis-Beddington functional response, and that the predator emigration response to prey has destabilizing effects similar to that of the Holling type II response. A stability criterion describing the net effect of the two emigration responses on a Lotka-Volterra predator-prey system is presented. The winner of the space race (i.e. whether predators or prey are favoured) is determined by the relationship between the slopes of the species' emigration responses. It is predicted that predators win the space race in poor habitats, where predator and prey densities are low, and that prey are more successful in richer habitats. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  17. Linked Data: an Evolution

    Directory of Open Access Journals (Sweden)

    Karen Coyle

    2013-01-01

    Full Text Available Actually the world is full of hi-tech devices that allow in different ways to stay always connected and up-to-date. The high level of interactivity and interoperability is now a fundamental prerogative in the new millennium communication which no one can be exempted. In particular, librarian universe must reconfigure this new way to exchange and provide information otherwise it will cause the steady decline, and this will cause a huge loss of users who will find different ways to information: such as tablet or smartphone. The linked data can provide significant support for libraries to ensure that they can still be leaders in the future. A brief mention to the studies conducted in this domain.

  18. Linking specification to differentiation

    Science.gov (United States)

    zur Lage, Petra I; Simpson, T Ian

    2011-01-01

    Much of developmental biology is concerned with the processes by which cells become committed to particular fates in a regulated fashion, whereas cell biology addresses, among other things, the variety of differentiated forms and functions that cells can acquire. One open question is how the regulators of the former process lead to attainment of the latter. “High-level” regulators of cell fate specification include the proneural factors, which drive cells to commit as precursors in the sensory nervous system. Recent research has concentrated on the gene expression events downstream of proneural factor function. Here we summarize this research and describe our own research that has provided clear links between a proneural factor, atonal and the cell biological program of ciliogenesis, which is a central aspect of sensory neuron differentiation. PMID:21558799

  19. Named Entity Linking Algorithm

    Directory of Open Access Journals (Sweden)

    M. F. Panteleev

    2017-01-01

    Full Text Available In the tasks of processing text in natural language, Named Entity Linking (NEL represents the task to define and link some entity, which is found in the text, with some entity in the knowledge base (for example, Dbpedia. Currently, there is a diversity of approaches to solve this problem, but two main classes can be identified: graph-based approaches and machine learning-based ones. Graph and Machine Learning approaches-based algorithm is proposed accordingly to the stated assumptions about the interrelations of named entities in a sentence and in general.In the case of graph-based approaches, it is necessary to solve the problem of identifying an optimal set of the related entities according to some metric that characterizes the distance between these entities in a graph built on some knowledge base. Due to limitations in processing power, to solve this task directly is impossible. Therefore, its modification is proposed. Based on the algorithms of machine learning, an independent solution cannot be built due to small volumes of training datasets relevant to NEL task. However, their use can contribute to improving the quality of the algorithm. The adaptation of the Latent Dirichlet Allocation model is proposed in order to obtain a measure of the compatibility of attributes of various entities encountered in one context.The efficiency of the proposed algorithm was experimentally tested. A test dataset was independently generated. On its basis the performance of the model was compared using the proposed algorithm with the open source product DBpedia Spotlight, which solves the NEL problem.The mockup, based on the proposed algorithm, showed a low speed as compared to DBpedia Spotlight. However, the fact that it has shown higher accuracy, stipulates the prospects for work in this direction.The main directions of development were proposed in order to increase the accuracy of the system and its productivity.

  20. In-Space Networking on NASA's SCAN Testbed

    Science.gov (United States)

    Brooks, David E.; Eddy, Wesley M.; Clark, Gilbert J.; Johnson, Sandra K.

    2016-01-01

    The NASA Space Communications and Navigation (SCaN) Testbed, an external payload onboard the International Space Station, is equipped with three software defined radios and a flight computer for supporting in-space communication research. New technologies being studied using the SCaN Testbed include advanced networking, coding, and modulation protocols designed to support the transition of NASAs mission systems from primarily point to point data links and preplanned routes towards adaptive, autonomous internetworked operations needed to meet future mission objectives. Networking protocols implemented on the SCaN Testbed include the Advanced Orbiting Systems (AOS) link-layer protocol, Consultative Committee for Space Data Systems (CCSDS) Encapsulation Packets, Internet Protocol (IP), Space Link Extension (SLE), CCSDS File Delivery Protocol (CFDP), and Delay-Tolerant Networking (DTN) protocols including the Bundle Protocol (BP) and Licklider Transmission Protocol (LTP). The SCaN Testbed end-to-end system provides three S-band data links and one Ka-band data link to exchange space and ground data through NASAs Tracking Data Relay Satellite System or a direct-to-ground link to ground stations. The multiple data links and nodes provide several upgradable elements on both the space and ground systems. This paper will provide a general description of the testbeds system design and capabilities, discuss in detail the design and lessons learned in the implementation of the network protocols, and describe future plans for continuing research to meet the communication needs for evolving global space systems.

  1. Genetic Algorithm Based Optimization of a Two Link Planar Robot Manipulator

    OpenAIRE

    G. Chaitanyaa; Reddy Sreenivasulu

    2016-01-01

    A two link revolute robotic arm is optimized for maximization of work space area covered by its end effector. A mathematical model for optimization is built considering singularities which influence the variation of design variables. Condition number which is the measure of output value (End effector position) for a small change in input value (joint angles) is modeled as the constraint. Joint angle between link2 and link1 and link lengths are considered as design variabl...

  2. Performance Analysis of ARQ-Based RF-FSO Links

    KAUST Repository

    Makki, Behrooz

    2017-02-22

    We study the performance of hybrid radio-frequency (RF) and free-space optical (FSO) links using automatic repeat request (ARQ). We derive closed-form expressions for the throughput and outage probability with different channel models. We also evaluate the effect of adaptive power allocation between the ARQ retransmissions on the system performance. The results show that joint implementation of the RF and FSO links leads to substantial performance improvement, compared to the cases with only the RF or the FSO link.

  3. Space Detectives

    Science.gov (United States)

    Tyszka, Steph; Saraiva, Jose; Doran, Rosa

    2017-04-01

    NUCLIO is a Portuguese non-profit organization with a strong record of investing in science education and outreach. We have developed and implemented many activities mostly directed to a young audience, in a bid to awaken and reinforce the interest that young people devote to Astronomy and all things spatial. In this framework, we have created a week-long program called Space Detectives, supported by the Municipality of Cascais, based on a story-line that provided a number of challenges and opportunities for learning matters as diverse as the electro-magnetic spectrum, means of communication, space travel, the martian environment, coding and robotics. We report on the first session that took place in December 2016. We had as participants several kids aged 9 to 12, with a mixed background in terms of interest in the sciences. Their response varied from enthusiastic to somewhat less interested, depending on the nature of the subject and the way it was presented - a reaction not necessarily related to its complexity. This week was taken as something of a trial run, in preparation for the European Commission- funded project "Stories of Tomorrow", to be implemented in schools. The individual activities and the way they were related to the story-line, as well as the smooth transition from one to the next, were subject to an analysis that will allow for improvements in the next installments of this program. We believe this is an excellent approach to the goals of using Space and Astronomy as an anchor for generating and keeping interest in the scientific areas, and of finding new and richer ways of learning.

  4. Grounding word learning in space.

    Science.gov (United States)

    Samuelson, Larissa K; Smith, Linda B; Perry, Lynn K; Spencer, John P

    2011-01-01

    Humans and objects, and thus social interactions about objects, exist within space. Words direct listeners' attention to specific regions of space. Thus, a strong correspondence exists between where one looks, one's bodily orientation, and what one sees. This leads to further correspondence with what one remembers. Here, we present data suggesting that children use associations between space and objects and space and words to link words and objects--space binds labels to their referents. We tested this claim in four experiments, showing that the spatial consistency of where objects are presented affects children's word learning. Next, we demonstrate that a process model that grounds word learning in the known neural dynamics of spatial attention, spatial memory, and associative learning can capture the suite of results reported here. This model also predicts that space is special, a prediction supported in a fifth experiment that shows children do not use color as a cue to bind words and objects. In a final experiment, we ask whether spatial consistency affects word learning in naturalistic word learning contexts. Children of parents who spontaneously keep objects in a consistent spatial location during naming interactions learn words more effectively. Together, the model and data show that space is a powerful tool that can effectively ground word learning in social contexts.

  5. Space Pharmacology

    CERN Document Server

    Wotring, Virginia E

    2012-01-01

    Space Pharmacology” is a review of the current knowledge regarding the use of pharmaceuticals during spaceflights. It is a comprehensive review of the literature, addressing each area of pharmacokinetics and each major physiological system in turn. Every section begins with a topic overview, and is followed by a discussion of published data from spaceflight, and from ground experiments meant to model the spaceflight situation. Includes a discussion looking forward to the new medical challenges we are likely to face on longer duration exploration missions. This book is a snapshot of our current knowledge that also highlights areas of unknown.

  6. Unliveable Spaces

    DEFF Research Database (Denmark)

    Johannessen, Runa

    The thesis is concerned with spatial practices of resistance employed in Palestinian struggles against Israel’s violent dispossession of Palestinian land through half a century of occupation. In the political configuration of the built space of the West Bank, architecture appears as a tactically......, fundamentally, who has the right to a future in this land. By viewing architecture in its dual dimension of praxis and object, built structures are investigated as agents that induce and manifest territorial struggles. The spatial instrumentalisation of architecture is effected by Israel through commonplace...

  7. Space exploration

    CERN Document Server

    2009-01-01

    Space Exploration, is one book in the Britannica Illustrated Science Library Series that is correlated to the science curriculum in grades 5-8. The Britannica Illustrated Science Library is a visually compelling set that covers earth science, life science, and physical science in 16 volumes.  Created for ages 10 and up, each volume provides an overview on a subject and thoroughly explains it through detailed and powerful graphics-more than 1,000 per volume-that turn complex subjects into information that students can grasp.  Each volume contains a glossary with full definitions for vocabulary help and an index.

  8. Space Food

    Science.gov (United States)

    1994-01-01

    In planning for the long duration Apollo missions, NASA conducted extensive research into space food. One of the techniques developed was freeze drying. Action Products commercialized this technique, concentrating on snack food including the first freeze-dried ice cream. The foods are cooked, quickly frozen and then slowly heated in a vacuum chamber to remove the ice crystals formed by the freezing process. The final product retains 98 percent of its nutrition and weighs only 20 percent of its original weight. Action snacks are sold at museums, NASA facilities and are exported to a number of foreign countries. Sales run to several million dollars annually.

  9. Too Many Links in the Horizon; What is Next? Linked Views and Linked History

    NARCIS (Netherlands)

    E. Liarou (Erietta); S. Idreos (Stratos)

    2011-01-01

    textabstractThe trend for more online linked data becomes stronger. Foreseeing a future where ``everything" will be online and linked, we ask the critical question; what is next? We envision that managing, querying and storing large amounts of links and data is far from yet another query

  10. Impact of Various Parameters on the Performance of Inter-aircraft Optical Wireless Communication Link

    Science.gov (United States)

    Singh, Mehtab

    2017-12-01

    Optical wireless communication (OWC) systems also known as Free space optics (FSO) are capable of providing high channel bandwidth, high data transmission rates, low power consumption, and high security. OWC links are being considered in different applications such as inter-satellite links, terrestrial links, and inter-aircraft communication links. This paper investigates the impact of different system parameters such as transmission power level, operating wavelength, transmitter pointing error angle, bit transmission rate, atmospheric attenuation, antenna aperture diameter, geometric losses, the responsivity of the photodetector, and link range on the performance of inter-aircraft optical wireless communication link.

  11. Space charge

    CERN Document Server

    Schindl, Karlheinz

    2005-01-01

    The Coulomb forces between the charged particles of a high-intensity beam in an accelerator create a self-field which acts on the particles inside the beam like a distributed lens, defocusing in both transverse planes. A beam moving with speed n is accompanied by a magnetic field which partially cancels the electrostatic defocusing effect, with complete cancellation at c, the speed of light. The effect of this 'direct space charge' is evaluated for transport lines and synchrotrons where the number of betatron oscillations per machine turn, Q, is reduced by DQ. In a real accelerator, the beam is also influenced by the environment (beam pipe, magnets, etc.) which generates 'indirect' space charge effects. For a smooth and perfectly conducting wall, they can easily be evaluated by introducing image charges and currents. These 'image effects' do not cancel when n approaches c, thus they become dominant for high-energy synchrotrons. Each particle in the beam has its particular incoherent tune Q and incoherent tune...

  12. Space activities and global popular music culture

    Science.gov (United States)

    Wessels, Allison Rae; Collins, Patrick

    During the "space age" era, space activities appear increasingly as a theme in Western popular music, as they do in popular culture generally. In combination with the electronics and tele-communications revolution, "pop/rock" music has grown explosively during the space age to become an effectively global culture. From this base a number of trends are emerging in the pattern of influences that space activities have on pop music. The paper looks at the use of themes and imagery in pop music; the role of space technology in the modern "globalization" of pop music; and current and future links between space activities and pop music culture, including how public space programmes are affected by its influence on popular attitudes.

  13. UV photobiochemistry under space conditions

    Science.gov (United States)

    Dose, K.; Bieger-Dose, A.; Dillmann, R.; Gill, M.; Kerz, O.; Klein, A.; Stridde, C.

    The response of spores of Bacillus subtilis, cells of Deinococcus radiodurans and conidia of Aspergillus ochraceus to actual and simulated space conditions (UV in combination with long-term exposure to extremely dry conditions, including vacuum) has been studied: The following effects have been analyzed: decrease of viability, occurrence of DNA double strand breaks, formation of DNA-protein cross-links and DNA-DNA cross-links. All organisms show an increased sensitivity to UV light in extreme dryness (dry argon or vacuum) compared to an irradiation in aqueous suspension. The UV irradiation leads in all cases to a variety of DNA lesions. Very conspicuous is the occurrence of double strand breaks. Most of these double strand breaks are produced by incomplete repair of other lesions, especially base damages. The increase in DNA lesions can be correlated to the loss in viability. The specific response of the chromosomal DNA to UV irradiation in extreme dryness, however, varies from species to species and depends on the state of dehydration. The formation of DNA double strand breaks and DNA-protein cross-links prevails in the case of B. subtilis spores. In cells of Deinococcus radiodurans DNA-DNA cross-links often predominate, in conidia of Aspergillus ochraceus double strand breaks. The results obtained by direct exposure to space conditions (EURECA mission and D2 mission) largely agree with the laboratory data.

  14. Space platforms

    Science.gov (United States)

    1983-04-01

    The expanded scientific capabilities available by interfacing an orbital, free-flying experiments platform with Shuttle tending are outlined. The platform would be lifted to orbit by the Shuttle, and modularly increased in size on subsequent flights. Science packages could be left on the 26,000 lb space platform for up to six months. Component sections would include electrical and thermal control systems, berthing ports for payloads and an Orbiter, and an attitude control, communications, and data handling subsection. A 12 kW solar array would furnish power, and interconnect with Spacelab would further enhance the operations range. All berthed science packages would have individual pointing ability and grapples for the Orbiter RMS. Eventual evolution to include facilities for a human crew and a 25 kW solar array is projected.

  15. Using ATM over SATCOM links

    Science.gov (United States)

    Comparetto, Gary M.

    1995-01-01

    The Asynchronous Transfer Mode (ATM) protocol is studied from the standpoint of determining what limitations, if any, exist in using it over satellite links. It is concluded that, while there is nothing intrinsic about ATM that would generally preclude its use over satellite links, there are, however, several intrinsic characteristics of satellite links, as well as some satellite system configuration-specific issues, that must be taken into account.

  16. Port-based modeling of a flexible link

    NARCIS (Netherlands)

    Macchelli, A.; Macchelli, A.; Hirohika, A.; Lynch, K.; Melchiorri, C.; Park, F.C.; Stramigioli, Stefano; Parker, L.E.

    In this paper, a simple way to model flexible robotic links is presented. This is different from classical approaches and from the Euler–Bernoulli or Timoshenko theory, in that the proposed model is able to describe large deflections in 3-D space and does not rely on any finite-dimensional

  17. A Quantum Space behind Simple Quantum Mechanics

    Directory of Open Access Journals (Sweden)

    Chuan Sheng Chew

    2017-01-01

    Full Text Available In physics, experiments ultimately inform us about what constitutes a good theoretical model of any physical concept: physical space should be no exception. The best picture of physical space in Newtonian physics is given by the configuration space of a free particle (or the center of mass of a closed system of particles. This configuration space (as well as phase space can be constructed as a representation space for the relativity symmetry. From the corresponding quantum symmetry, we illustrate the construction of a quantum configuration space, similar to that of quantum phase space, and recover the classical picture as an approximation through a contraction of the (relativity symmetry and its representations. The quantum Hilbert space reduces into a sum of one-dimensional representations for the observable algebra, with the only admissible states given by coherent states and position eigenstates for the phase and configuration space pictures, respectively. This analysis, founded firmly on known physics, provides a quantum picture of physical space beyond that of a finite-dimensional manifold and provides a crucial first link for any theoretical model of quantum space-time at levels beyond simple quantum mechanics. It also suggests looking at quantum physics from a different perspective.

  18. Drugs + HIV, Learn the Link

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  19. Empty Spaces.

    Science.gov (United States)

    Hulkower, Adira

    2017-09-01

    "I'm Jewish, you know, and my mother said, 'Always trust the rabbis.'" I never heard Mr. Weisman's refrain from his own lips. I never heard him say any words all. By the time I met him he was in a vegetative state, a man on the precipice of invisibility-white hair, thin pale limbs, melting into sheets of the same color. When I think about Mr. Weisman, I see empty spaces-the absence of his voice, the too-large bed for his shrinking frame, the always-empty chair by his bedside, and most of all, the myriad gaps in his life story. He was what in hospitals is often called a "patient alone": someone who lacks decisional capacity and has no surrogate to make medical decisions for him. Mr. Weisman's aloneness prompted his primary team to consult our bioethics service in order to formulate goals of care for him, including the possibility of hospice care. © 2017 The Hastings Center.

  20. The Space Puppets

    Science.gov (United States)

    Lago, M. Miguel; Esteban Berea, J.; Miñambres Fernández, M.; Rufino, M.

    2002-01-01

    This proposal is a response to the initiative "Physics on Stage 2" to excite interest in physics and science by a dance and puppetry performance. The purpose of this piece is to show the possibilities and characteristics of entertainment with space knowledge and education for the audience of teachers and children through a show. Two virtually opposite areas (science and arts), both generally inaccessible for children, will be introduced in a funny and amusing way, with the interaction of puppets. Education is not "fashion"... we need to develop an educational package to focus the attention of children on the uses of Space in everyday life. Our world today is mainly logic and mathematical. The presence of art in the children's lives is often scarce or even inexistent. With the performance children will gain a better understanding of space physics through the joy of a dance performance like an educational tool. Dance as body expression, is a very powerful tool to explain and interact with children and teachers. Through dance the physics of movement may be studied in a visual way, within the body's limits. We consider as priority the use of dance as well as theater (in this case, puppet theater) as an efficient and fun didactic method, which we may go further and explain in an imaginative funny way all those complex processes of physics, which are further unknown. Aiming to teach in a relaxing atmosphere the performance is based on the " Earth Space Alphabet", a first dictionary for Primary Schools combining Science, Space and Education... Did you ever realize that people are not interested in something because they do not understand the words or the meaning? The alphabet is intended to meet the overwhelming need that exists for education on space, and allows both teachers and children to learn about the "Art of Teaching Space" combining earth and space language linked by space technology. The performance explains many concepts of physics through a comet puppet, which

  1. Space Science in Action: Space Exploration [Videotape].

    Science.gov (United States)

    1999

    In this videotape recording, students learn about the human quest to discover what is out in space. Students see the challenges and benefits of space exploration including the development of rocket science, a look back at the space race, and a history of manned space travel. A special section on the Saturn V rocket gives students insight into the…

  2. Space teleoperations technology for Space Station evolution

    Science.gov (United States)

    Reuter, Gerald J.

    1990-01-01

    Viewgraphs on space teleoperations technology for space station evolution are presented. Topics covered include: shuttle remote manipulator system; mobile servicing center functions; mobile servicing center technology; flight telerobotic servicer-telerobot; flight telerobotic servicer technology; technologies required for space station assembly; teleoperation applications; and technology needs for space station evolution.

  3. Linking Wikipedia to the web

    NARCIS (Netherlands)

    Kaptein, R.; Serdyukov, P.; Kamps, J.; Chen, H.-H.; Efthimiadis, E.N.; Savoy, J.; Crestani, F.; Marchand-Maillet, S.

    2010-01-01

    We investigate the task of finding links from Wikipedia pages to external web pages. Such external links significantly extend the information in Wikipedia with information from the Web at large, while retaining the encyclopedic organization of Wikipedia. We use a language modeling approach to create

  4. Game Changer: Linked Learning Detroit

    Science.gov (United States)

    ConnectEd: The California Center for College and Career, 2016

    2016-01-01

    JP Morgan Chase joins the Skillman Foundation, the Ford Foundation, and the Ford Motor Company Fund, whose grants total $7 million and will connect 10,000 Detroit high school students to career education and work experiences over the next three years through Linked Learning Detroit. Learn about Linked Learning Detroit through interviews with…

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  8. [Sex-linked juvenile retinoschisis].

    Science.gov (United States)

    François, P; Turut, P; Soltysik, C; Hache, J C

    1976-02-01

    About 13 observations of sexe linked juvenile retinoschisis, the authors describe the ophthalmoscopic, fluorographic and functional aspects of the disease whose caracteristics are:--its sexe linked recessive heredity; --its clinical characterestics associating: a microcystic macular degeneration, peripheral retinal lesions, vitreous body alterations, --an electroretinogram of the negative type.

  9. Interpreting Linked Psychomotor Performance Scores

    Science.gov (United States)

    Looney, Marilyn A.

    2013-01-01

    Given that equating/linking applications are now appearing in kinesiology literature, this article provides an overview of the different types of linked test scores: equated, concordant, and predicted. It also addresses the different types of evidence required to determine whether the scores from two different field tests (measuring the same…

  10. Drugs + HIV, Learn the Link

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  14. Hypermedia: The Link with Time

    NARCIS (Netherlands)

    L. Hardman (Lynda); J.R. van Ossenbruggen (Jacco); L. Rutledge (Lloyd); D.C.A. Bulterman (Dick)

    1999-01-01

    textabstractThis essay presents a brief discussion of combining temporal aspects of multimedia presentations with hypertext links. Three ways of combining linking with temporally synchronized components of a presentation are described. We describe work that has been done to incorporate both temporal

  15. Optimizing pointer linked data structures

    NARCIS (Netherlands)

    Holm, Carl Wilhelm Mattias

    2013-01-01

    The thesis explores different ways of optimizing pointer linked data structures, and especially restructuring them. The mechanisms are based on compiler technology, theory, computer languages and hardware architecture that are capable of optimizing the memory layout of complex pointer linked data

  16. Drugs + HIV, Learn the Link

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  17. Drugs + HIV, Learn the Link

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  18. Drugs + HIV, Learn the Link

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  19. Drugs + HIV, Learn the Link

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    Full Text Available ... at: http://www.drugabuse.gov/news-events/public-education-projects/learn-link-drugs-hiv . 120x90 460x80 486x60 Social Media Send the message to young people and to parents, teachers, and the media about the link between drug ...

  20. Drugs + HIV, Learn the Link

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    Full Text Available ... Learn the Link campaign uses TV, print, and Web public service announcements (PSAs), as well as posters, e-cards, ... to misuse drugs. The Learn the Link public service campaign is just one ... this Web site. Sincerely, Nora D. Volkow, M.D. Director ...

  1. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Plan Search Share Print Home » News & Events » Public Education Projects » Learn the Link - Drugs and HIV Learn the Link - Drugs and HIV Email Facebook Twitter 2005 –Ongoing Behaviors associated with drug misuse are among the main factors in the spread of HIV infection in the ...

  2. LOTUS: Linked open text unleashed

    NARCIS (Netherlands)

    Ilievski, F.; Beek, Wouter; Van Erp, Marieke; Rietveld, Laurens; Schlobach, Stefan

    2015-01-01

    It is dificult to find resources on the Semantic Web today, in particular if one wants to search for resources based on natural language keywords and across multiple datasets. In this paper, we present LOTUS: Linked Open Text UnleaShed, a full-text lookup index over a huge Linked Open Data

  3. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... projects/learn-link-drugs-hiv . 120x90 460x80 486x60 Social Media Send the message to young people and ... NIDA’s "Learn the Link" campaign continues to raise awareness among this generation of the real risks of ...

  4. Decouplink: Dynamic Links for Java

    DEFF Research Database (Denmark)

    Jensen, Martin Lykke Rytter; Jørgensen, Bo Nørregaard

    2011-01-01

    of dimensions of extension that can be exploited without performing modification of existing types. Thus, dynamic links make it possible to enforce the open/closed principle in situations where it would otherwise not be possible. We present Decouplink – a library-based implementation of dynamic links for Java...

  5. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... people use to weigh risks and benefits when making decisions. This page connects you to information about the link between drug abuse and HIV infection. It contains information for young people, parents and teachers, and the media with links to our latest research findings and ...

  6. STS-106 Onboard Photograph - International Space Station

    Science.gov (United States)

    2000-01-01

    This image of the International Space Station (ISS) was taken when Space Shuttle Atlantis (STS-106 mission) approached the ISS for docking. At the top is the Russian Progress supply ship that is linked with the Russian built Service Module or Zvezda. The Zvezda is cornected with the Russian built Functional Cargo Block (FGB) or Zarya. The U.S. built Node 1 or Unity module is seen at the bottom.

  7. Analysis of Free-Space Optics Development

    Directory of Open Access Journals (Sweden)

    Mikołajczyk Janusz

    2017-12-01

    Full Text Available The article presents state of work in technology of free-space optical communications (Free Space Optics − FSO. Both commercially available optical data links and their further development are described. The main elements and operation limiting factors of FSO systems have been identified. Additionally, analyses of FSO/RF hybrid systems application are included. The main aspects of LasBITer project related to such hybrid technology for security and defence applications are presented.

  8. GENERAL IN AIR AND SPACE LAW

    Directory of Open Access Journals (Sweden)

    Z. Z. Khalilov

    2015-01-01

    Full Text Available The article deals with the study of link between air and space law, the problem of determining the boundaries of the airspace is investigated. The international practices of various institutions of air and space law, in particular, in Europe, Argentina, Turkey, and the practice of studying these issues in joint form within the research Institute of the Republic of Azerbaijan are analyzed.

  9. Preparing future space leaders - International Space University

    Science.gov (United States)

    Stone, Barbara A.; Van Reeth, George P.

    1992-01-01

    The International Space University (ISU) concept of developing a cadre of space professionals that will lead the universities and industries into space is discussed. ISU is an innovative, permanent worldwide organization for training and academic instruction in all aspects of space studies. ISU's major goal is to provide the young professional academic instruction in technical and nontechnical areas of modern space exploration and research, and a forum to exchange ideas and develop both personal and professional ties at an international level.

  10. SetLink: the CERN Document Server Link Manager

    OpenAIRE

    Le Meur, Jean-Yves; McGlashan, David

    2000-01-01

    This paper analyses the problems encountered by electronic libraries to cope with long term keeping of on-line documents. What is the best solution not to fill in a library system with non persistent addresses? Different possible solutions are studied, based on the experience of the CERN Document Server and its library. This paper will stress the importance of using a Link Manager for any long term Web server. It will explain how the CERN SetLink Link Manager is designed to handle a wide ...

  11. Space Biosciences, Space-X, and the International Space Station

    Science.gov (United States)

    Wigley, Cecilia

    2014-01-01

    Space Biosciences Research on the International Space Station uses living organisms to study a variety of research questions. To enhance our understanding of fundamental biological processes. To develop the fundations for a safe, productive human exploration of space. To improve the quality of life on earth.

  12. Loop Heat Pipe with Thermal Control Valve for Passive Variable Thermal Link Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Future Lunar Landers and Rovers will require variable thermal links that can reject heat during daytime, and passively shut-off during lunar night. During the long...

  13. 77 FR 58210 - 31st Meeting: RTCA Special Committee 206, Aeronautical Information and Meteorological Data Link...

    Science.gov (United States)

    2012-09-19

    ... Presentations: Category 1 End-to-End Performance Metrics paper Human Factors Product Evaluation paper Data Link... open to the interested public but limited to space availability. With the approval of the chairman...

  14. The Missing Link: The Use of Link Words and Phrases as a Link to Manuscript Quality

    Science.gov (United States)

    Onwuegbuzie, Anthony J.

    2016-01-01

    In this article, I provide a typology of transition words/phrases. This typology comprises 12 dimensions of link words/phrases that capture 277 link words/phrases. Using QDA Miner, WordStat, and SPSS--a computer-assisted mixed methods data analysis software, content analysis software, and statistical software, respectively--I analyzed 74…

  15. Health Issues and Space Weather

    Science.gov (United States)

    Crosby, N.

    2009-04-01

    The possibility that solar activity and variations in the Earth's magnetic field may affect human health has been debated for many decades but is still a "scientific topic" in its infancy. By learning whether and, if so, how much the Earth's space weather can influence the daily health of people will be of practical importance. Knowing whether human genetics, include regulating factors that take into account fluctuations of the Earth's magnetic field and solar disturbances, indeed exist will also benefit future interplanetary space travelers. Because the atmospheres on other planets are different from ours, as well as their interaction with the space environment, one may ask whether we are equipped with the genetics necessary to take this variability into account. The goal of this presentation is to define what is meant by space weather as a health risk and identify the long-term socio-economic effects on society that such health risks would have. Identifying the physical links between space weather sources and different effects on human health, as well as the parameters (direct and indirect) to be monitored, the potential for such a cross-disciplinary study will be invaluable, for scientists and medical doctors, as well as for engineers.

  16. High-Efficiency, High-Power Laser Transmitter for Deep-Space Communication Project

    Data.gov (United States)

    National Aeronautics and Space Administration — There is demand for vastly improved deep space satellite communications links. As data rates dramatically increase due to new sensor technologies and the desire to...

  17. On the performance of millimeter wave-based RF-FSO links with HARQ feedback

    KAUST Repository

    Makki, Behrooz

    2016-12-24

    This paper studies the performance of hybrid radio-frequency (RF) and free-space optical (FSO) links in the cases with and without hybrid automatic repeat request (HARQ). Considering millimeter wave (mmwave) characteristics in the RF link and pointing errors in the FSO link, we derive closed-form expressions for the message decoding probabilities as well as the throughput and the outage probability of the RF-FSO setups. We also evaluate the effect of various parameters such as power amplifiers efficiency, different transmission techniques in the FSO link, pointing errors in the FSO link as well as different coherence times/symbol rates of the RF and the FSO links on the throughput and outage probability. The results show the efficiency of the RF-FSO links in different conditions. Moreover, the HARQ can effectively improve the outage probability/energy efficiency, and compensate the effect of hardware impairments in RF-FSO links.

  18. Integrated Modeling, Analysis, and Verification for Space Missions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project will further MBSE technology in fundamental ways by strengthening the link between SysML tools and framework engineering execution environments. Phoenix...

  19. Space Biophysics: Accomplishments, Trends, Challenges

    Science.gov (United States)

    Smith, Jeffrey D.

    2015-01-01

    Physics and biology are inextricably linked. All the chemical and biological processes of life are dutifully bound to follow the rules and laws of physics. In space, these physical laws seem to turn on their head and biological systems, from microbes to humans, adapt and evolve in myriad ways to cope with the changed physical influences of the space environment. Gravity is the most prominent change in space that influences biology. In microgravity, the physical processes of sedimentation, density-driven convective flow, influence of surface tension and fluid pressure profoundly influence biology at the molecular and cellular level as well as at the whole-body level. Gravity sensing mechanisms are altered, structural and functional components of biology (such as bone and muscle) are reduced and changes in the way fluids and gasses behave also drive the way microbial systems and biofilms grow as well as the way plants and animals adapt. The radiation environment also effects life in space. Solar particle events and high energy cosmic radiation can cause serious damage to DNA and other biomolecules. The results can cause mutation, cellular damage or death, leading to health consequences of acute radiation damage or long-term health consequences such as increased cancer risk. Space Biophysics is the study and utilization of physical changes in space that cause changes in biological systems. The unique physical environment in space has been used successfully to grow high-quality protein crystals and 3D tissue cultures that could not be grown in the presence of unidirectional gravitational acceleration here on Earth. All biological processes that change in space have their root in a biophysical alteration due to microgravity and/or the radiation environment of space. In order to fully-understand the risks to human health in space and to fully-understand how humans, plants, animals and microbes can safely and effectively travel and eventually live for long periods beyond

  20. Calbindins decreased after space flight

    Science.gov (United States)

    Sergeev, I. N.; Rhoten, W. B.; Carney, M. D.

    1996-01-01

    Exposure of the body to microgravity during space flight causes a series of well-documented changes in Ca2+ metabolism, yet the cellular and molecular mechanisms leading to these changes are poorly understood. Calbindins, vitamin D-dependent Ca2+ binding proteins, are believed to have a significant role in maintaining cellular Ca2+ homeostasis. In this study, we used biochemical and immunocytochemical approaches to analyze the expression of calbindin-D28k and calbindin-D9k in kidneys, small intestine, and pancreas of rats flown for 9 d aboard the space shuttle. The effects of microgravity on calbindins in rats from space were compared with synchronous Animal Enclosure Module controls, modeled weightlessness animals (tail suspension), and their controls. Exposure to microgravity resulted in a significant and sustained decrease in calbindin-D28k content in the kidney and calbindin-D9k in the small intestine of flight animals, as measured by enzyme-linked immunosorbent assay (ELISA). Modeled weightlessness animals exhibited a similar decrease in calbindins by ELISA. Immunocytochemistry (ICC) in combination with quantitative computer image analysis was used to measure in situ the expression of calbindins in the kidney and the small intestine, and the expression of insulin in pancreas. There was a large decrease of immunoreactivity in renal distal tubular cell-associated calbindin-D28k and in intestinal absorptive cell-associated calbindin-D9k of space flight and modeled weightlessness animals compared with matched controls. No consistent difference in pancreatic insulin immunoreactivity between space flight, modeled weightlessness, and controls was observed. Regression analysis of results obtained by quantitative ICC and ELISA for space flight, modeled weightlessness animals, and their controls demonstrated a significant correlation. These findings after a short-term exposure to microgravity or modeled weightlessness suggest that a decreased expression of calbindins

  1. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... patients who do not abuse drugs. In animal studies, methamphetamine has been shown to increase the amount ... behaviors. NIDA researchers have studied and continue to study the links between drug abuse and HIV/AIDS. ...

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    Medline Plus

    Full Text Available ... never thought that one party could change their lives , but now their night out always will be ... reach parents and teachers—influential figures in the lives of young people—with the Learn the Link ...

  3. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Campaign Overview The Learn the Link campaign uses TV, print, and Web public service announcements (PSAs), as ... CW BET NBC ABC FOX LATV My Network TV Organizations: AIDS.gov AIDS Alliance for Children, Youth ...

  4. EPA Linked Open Data (Collection)

    Data.gov (United States)

    U.S. Environmental Protection Agency — This is a collection item referencing the following EPA Linked Data resources: - EPA Facility Registry Service (FRS) - EPA Substance Registry Service (SRS) -...

  5. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... AIDS (acquired immune deficiency syndrome). AIDS is a disease of the immune system for which there is ... the present time. The virus (HIV) and the disease it causes (AIDS) are often linked and referred ...

  6. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... public discussions on using new media effectively in response to HIV/AIDS, as well as HIV/AIDS ... HIV/AIDS and the discovery of promising treatment interventions for breaking the harmful links between them, we ...

  7. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... and teachers, and the media with links to our latest research findings and news updates. Read on ... the "Text Message" spot) from her own perspective. Our other campaign materials include print PSAs, Web banner ...

  8. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Prevention Recovery Substance Use and SUDs in LGBT Populations Treatment Trends & Statistics Women and Drugs Publications Search ... the link between drug abuse and HIV/AIDS, populations most at risk, trends in HIV/AIDS, and ...

  9. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Researchers Medical & Health Professionals Patients & Families Parents & Educators Children & Teens Search Connect with NIDA : Facebook LinkedIn Twitter ... Network TV Organizations: AIDS.gov AIDS Alliance for Children, Youth and Families The American Academy of Child & ...

  10. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... of HIV infection in the United States. Drugs can change the way the brain works, disrupting the ... linked and referred to as "HIV/AIDS." HIV can be transferred between people if an infected person's ...

  11. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... HIV Learn the Link - Drugs and HIV ... the parts of the brain that people use to weigh risks and benefits when making decisions. This page connects you to information about the ...

  12. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... their lives , but now their night out always will be associated with HIV/AIDS. The “d’cisions” ... for breaking the harmful links between them, we will continue to update this Web site. Sincerely, Nora ...

  13. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... En español Researchers Medical & Health Professionals Patients & Families Parents & Educators Children & Teens Search Connect with NIDA : Facebook ... HIV infection. It contains information for young people, parents and teachers, and the media with links to ...

  14. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Addiction Science Adolescent Brain Comorbidity College-Age & Young Adults Criminal Justice Drugged Driving Drug Testing Drugs and ... Link campaign. This campaign shows teens and young adults that non-injection drug use and alcohol use ...

  15. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... affect anyone. Watch the “d’cisions” Videos Campaign Materials After the Party Posters: We have developed posters ... the Learn the Link message. Campaign messages and materials were tested among various groups of young people, ...

  16. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... to this site at: http://www.drugabuse.gov/news-events/public-education-projects/learn-link-drugs-hiv . 120x90 460x80 486x60 Social Media Send the message to young people and to ...

  17. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... other organizations in your tweets to spread the word even further. Tweet About Learn the Link To ... other organizations in your tweets to spread the word even further. Share with Flickr, Pinterest or Instagram ...

  18. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... En español Researchers Medical & Health Professionals Patients & Families Parents & Educators Children & Teens Search Connect with NIDA : Facebook LinkedIn Twitter YouTube ...

  19. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Researchers Medical & Health Professionals Patients & Families Parents & Educators Children & Teens Search Connect with NIDA : Facebook LinkedIn Twitter YouTube Flickr RSS Menu Home Drugs of Abuse Commonly Abused Drugs Charts Emerging Trends and Alerts ...

  20. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... that use text messaging as a means of communication. The "Text Message" PSA features two young girls ... Drugs + HIV > Learn the Link campaign. This campaign shows teens and young adults that non-injection drug ...

  1. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available Skip to main content En español Researchers Medical & Health Professionals Patients & Families Parents & Educators Children & Teens Search Connect with NIDA : Facebook LinkedIn Twitter YouTube Flickr RSS ...

  2. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... easily copy and paste to help show your support for Learn the Link . Be sure to check ... the discussion between friends, and the importance of family. For more information, read a message from the ...

  3. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... can affect anyone. Watch the “d’cisions” Videos Campaign Materials After the Party Posters: We have developed ... share on your social media accounts. About the Campaign Overview The Learn the Link campaign uses TV, ...

  4. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... in recent years, HIV is no longer a death sentence, as it was when the epidemic began. ... Science USA Science & Engineering Festival Drug & Alcohol Chat Day HBO Addiction Project Learn the Link Videos NIDA ...

  5. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... NIDA Flickr account for images. Share your favorite image! Check out all of our ... Link campaign uses TV, print, and Web public service announcements (PSAs), as well as posters, ...

  6. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available Skip to main content En español Researchers Medical & Health Professionals Patients & Families Parents & Educators Children & Teens Search Connect with NIDA : Facebook LinkedIn Twitter YouTube Flickr RSS Menu ...

  7. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... among the main factors in the spread of HIV infection in the United States. Drugs can change the ... information about the link between drug misuse and HIV infection. It contains information for young people, parents and ...

  8. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... for Addiction Science USA Science & Engineering Festival Drug & Alcohol Chat Day HBO Addiction Project Learn the Link Videos NIDA and Scholastic - Heads Up NIDA Media Campaign Postcards Public Service Announcements Other Government Observances ...

  9. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... announcements (PSAs) that use text messaging as a means of communication. The "Text Message" PSA features two ... teens and young adults have never known a world without it. NIDA’s "Learn the Link" campaign continues ...

  10. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... the main factors in the spread of HIV infection in the United States. Drugs can change the ... about the link between drug abuse and HIV infection. It contains information for young people, parents and ...

  11. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... has shown that treating drug abuse is an effective way to prevent the spread of HIV. Drug ... HIV/AIDS and the discovery of promising treatment interventions for breaking the harmful links between them, we ...

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    Full Text Available ... she went to a party and under the influence of drugs and alcohol engaged in risky sexual ... other organizations in your tweets to spread the word even further. Tweet About Learn the Link To ...

  13. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... between drug abuse and HIV/AIDS. In the early years of the HIV epidemic, it became clear ... HIV/AIDS and the discovery of promising treatment interventions for breaking the harmful links between them, we ...

  14. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... HIV/AIDS, and the general public. U.S. National Library of Medicine HIV/AIDS ... send the message to young people and to parents, teachers, and the media about the link between ...

  15. Medicare and Medicaid Linked Files

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Medicare-Medicaid Linked Enrollee Analytic Data Source (MMLEADS) has been developed to allow for the examination of all Medicare and Medicaid enrollment and...

  16. Protein Linked to Atopic Dermatitis

    Science.gov (United States)

    ... Research Matters January 14, 2013 Protein Linked to Atopic Dermatitis Normal skin from a mouse (left) shows no ... that lack of a certain protein may trigger atopic dermatitis, the most common type of eczema. The finding ...

  17. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Web banner ads that you can download and add to your Web site. Please link these banners ... abuse and HIV. Post on Facebook or Twitter ; add photos to your Flickr , Pinterest , and Instagram pages; ...

  18. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... events, and radio stations for helping to raise awareness of the link between non-injection drug use and HIV. Television Networks: MunDos Azteca America Univision Telemundo Galavision ...

  19. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... through 15 (as well as their parents and teachers). It provides them with useful information on the ... the message to young people and to parents, teachers, and the media about the link between drug ...

  20. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... HIV (human immunodeficiency virus) is the virus that causes AIDS (acquired immune deficiency syndrome). AIDS is a ... time. The virus (HIV) and the disease it causes (AIDS) are often linked and referred to as " ...

  1. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Prevention Recovery Substance Use and SUDs in LGBT Populations Treatment Trends & Statistics Women and Drugs Publications Search ... the link between drug misuse and HIV/AIDS, populations most at risk, trends in HIV/AIDS, and ...

  2. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... NIDA’s "Learn the Link" campaign continues to raise awareness among this generation of the real risks of ... Collaborators Thanks to Those Who Have Helped Raise Awareness of Our Campaign! NIDA acknowledges the following television ...

  3. Drugs + HIV, Learn the Link

    Medline Plus

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  4. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... injury to cells in the brain and cognitive impairment among people who use methamphetamine than among HIV ... Link campaign. This campaign shows teens and young adults that non-injection drug use and alcohol use ...

  5. Drugs + HIV, Learn the Link

    Medline Plus

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  6. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... HIV/AIDS and the discovery of promising treatment interventions for breaking the harmful links between them, we ... Children, Youth and Families The American Academy of Child & Adolescent Psychiatry (AACAP) The United Negro College Fund, ...

  7. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Learn the Link Videos NIDA and Scholastic - Heads Up NIDA Media Campaign Postcards Public Service Announcements Other Government Observances for Substance Abuse Education Contact the Press Office Meetings & Events Media Guide ...

  8. Drugs + HIV, Learn the Link

    Medline Plus

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  9. Drugs + HIV, Learn the Link

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  10. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... affect anyone. Watch the “d’cisions” Videos Campaign Materials After the Party Posters: We have developed posters ... behaviors. NIDA researchers have studied and continue to study the links between drug misuse and HIV/AIDS. ...

  11. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Drugs and HIV Learn the Link - Drugs and HIV Email Facebook Twitter 2005 –Ongoing Behaviors associated with ... Send the Message . Get the Facts What are HIV and AIDS? HIV (human immunodeficiency virus) is the ...

  12. Drugs + HIV, Learn the Link

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  13. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... to-Read Drug Facts Web site describes the dangers of drug abuse and its link to HIV ... available for your use to share on your social media accounts. ... educational institutions, magazines, newspapers, companies, events, and ...

  14. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... and the discovery of promising treatment interventions for breaking the harmful links between them, we will continue to update this ... Media Campaign Postcards Public Service Announcements Other ...

  15. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... patients who do not misuse drugs. In animal studies, methamphetamine has been shown to increase the amount ... behaviors. NIDA researchers have studied and continue to study the links between drug misuse and HIV/AIDS. ...

  16. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... and HIV. We have produced a set of multicultural public service announcements (PSAs) that use text messaging ... NIDA’s "Learn the Link" campaign continues to raise awareness among this generation of the real risks of ...

  17. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... easily copy and paste to help show your support for Learn the Link . Be sure to check ... View Videos "After the Party" "Text Message" NIDA Home Site Map Accessibility Privacy FOIA(NIH) Working at ...

  18. Drugs + HIV, Learn the Link

    Medline Plus

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  19. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... NIDA Science Fair Award for Addiction Science USA Science & Engineering Festival Drug & Alcohol Chat Day HBO Addiction Project Learn the Link Videos NIDA and Scholastic - Heads Up NIDA Media Campaign Postcards Public Service Announcements Other Government Observances ...

  20. A Situative Space Model for Mobile Mixed-Reality Computing

    DEFF Research Database (Denmark)

    Pederson, Thomas; Janlert, Lars-Erik; Surie, Dipak

    2011-01-01

    This article proposes a situative space model that links the physical and virtual realms and sets the stage for complex human-computer interaction defined by what a human agent can see, hear, and touch, at any given point in time.......This article proposes a situative space model that links the physical and virtual realms and sets the stage for complex human-computer interaction defined by what a human agent can see, hear, and touch, at any given point in time....

  1. The Sun's Mysteries from Space-II

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 1. The Sun's Mysteries from Space – II. B N Dwivedi A Mohan. General Article Volume 10 Issue 1 January 2005 pp 6-16. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/010/01/0006-0016 ...

  2. Differential Calculus in Normed Linear Spaces

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 2. Differential Calculus in Normed Linear Spaces. Harish Seshadri. Book Review Volume 9 Issue 2 February 2004 pp 90-91. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/009/02/0090-0091 ...

  3. Linked data and user interaction

    CERN Document Server

    Cervone, H Frank

    2015-01-01

    This collection of research papers provides extensive information on deploying services, concepts, and approaches for using open linked data from libraries and other cultural heritage institutions. With a special emphasis on how libraries and other cultural heritage institutions can create effective end user interfaces using open, linked data or other datasets. These papers are essential reading for any one interesting in user interface design or the semantic web.

  4. Linking DC together with TRSL

    DEFF Research Database (Denmark)

    Haxthausen, Anne Elisabeth; Yong, X.

    2000-01-01

    Duration Calculus (DC) is an interval-based real-time logic, which can be used in capturing and eliciting users' real-time requirements. The Timed RAISE Specification Language (TRSL) is an extension of the RAISE Specification Language with real-time features. This paper links DC and TRSL together...... approach for linking state-based real-time logics together with event-based, timed process algebra languages....

  5. Linking Ethics and Economic Growth

    DEFF Research Database (Denmark)

    Foss, Nicolai Juul

    2012-01-01

    Hunt (2012) builds on his work concerning ethics and resource-advantage theory to link personal ethical standards, societal norms, and economic growth but offers few details concerning the precise mechanisms that link ethics and growth. This comment suggests a number of such mechanisms...... – for example, the influence of prevailing ethical norms on the aggregate elasticity of substitution and, therefore, total factor productivity and growth....

  6. Linearized Optically Phase-Modulated Fiber Optic Links for Microwave Signal Transport

    Science.gov (United States)

    2009-03-03

    25GHz ITU DWDM spacing. This particular link design and proof-of-concept experiment was able to meet several of the criteria that none of the other...efficiency of the link. FBGs that have been specifically designed for 25 GHz ITU grid DWDM channel demultiplexing will be substituted into the

  7. Link fermions in Euclidean lattice gauge theory

    Energy Technology Data Exchange (ETDEWEB)

    Brower, R.; Giles, R.; Maturana, G.

    1984-02-15

    The representation of the Wilson lattice fermion propagator as a sum over classical particle trajectories is discussed. A simple generalization of this path sum leads to an extended set of fermion theories characterized by one (or more) additional parameters. Such theories are nonlocal when written in terms of the usual four-component Dirac field. They are more naturally characterized by a local action functional whose degrees of freedom are those of a set of two-component Fermi fields defined on directed links of the lattice. Such lattice fields correspond to the direct product of a four-vector and Dirac spinor. For a suitable choice of parameters, the extended fermion theory offers a precocious approach to the continuum dispersion relation as the lattice spacing goes to zero and is therefore of interest for numerical studies of QCD.

  8. Selected legal challenges relating to the military use of outer space ...

    African Journals Online (AJOL)

    Since the end of the Second World War the potential use of outer space for military purposes persisted to be intrinsically linked to the development of space technology and space flight. The launch of the first artificial satellite, Sputnik 1, by the USSR in 1957 made Western states realise that a surprise attack from space was ...

  9. Atmosphere and Ambient Space

    DEFF Research Database (Denmark)

    Schmidt, Ulrik

    Atmosphere and Ambient Space This paper explores the relation between atmosphere and ambient space. Atmosphere and ambient space share many salient properties. They are both ontologically indeterminate, constantly varying and formally diffuse and they are both experienced as a subtle, non......-signifying property of a given space. But from a certain point of view, the two concepts also designate quite dissimilar experiences of space. To be ’ambient’ means to surround. Accordingly, ambient space is that space, which surrounds something or somebody. (Gibson 1987: 65) Since space is essentially...... of a surrounding character, all space can thus be described as having a fundamentally ambient character. So what precisely is an ambient space, then? As I will argue in my presentation, ambient space is a sensory effect of spatiality when a space is experienced as being particularly surrounding: a ‘space effect...

  10. Signed Link Analysis in Social Media Networks

    OpenAIRE

    Beigi, Ghazaleh; Tang, Jiliang; Liu, Huan

    2016-01-01

    Numerous real-world relations can be represented by signed networks with positive links (e.g., trust) and negative links (e.g., distrust). Link analysis plays a crucial role in understanding the link formation and can advance various tasks in social network analysis such as link prediction. The majority of existing works on link analysis have focused on unsigned social networks. The existence of negative links determines that properties and principles of signed networks are substantially dist...

  11. Linked Metadata - lightweight semantics for data integration (Invited)

    Science.gov (United States)

    Hendler, J. A.

    2013-12-01

    The "Linked Open Data" cloud (http://linkeddata.org) is currently used to show how the linking of datasets, supported by SPARQL endpoints, is creating a growing set of linked data assets. This linked data space has been growing rapidly, and the last version collected is estimated to have had over 35 billion 'triples.' As impressive as this may sound, there is an inherent flaw in the way the linked data story is conceived. The idea is that all of the data is represented in a linked format (generally RDF) and applications will essentially query this cloud and provide mashup capabilities between the various kinds of data that are found. The view of linking in the cloud is fairly simple -links are provided by either shared URIs or by URIs that are asserted to be owl:sameAs. This view of the linking, which primarily focuses on shared objects and subjects in RDF's subject-predicate-object representation, misses a critical aspect of Semantic Web technology. Given triples such as * A:person1 foaf:knows A:person2 * B:person3 foaf:knows B:person4 * C:person5 foaf:name 'John Doe' this view would not consider them linked (barring other assertions) even though they share a common vocabulary. In fact, we get significant clues that there are commonalities in these data items from the shared namespaces and predicates, even if the traditional 'graph' view of RDF doesn't appear to join on these. Thus, it is the linking of the data descriptions, whether as metadata or other vocabularies, that provides the linking in these cases. This observation is crucial to scientific data integration where the size of the datasets, or even the individual relationships within them, can be quite large. (Note that this is not restricted to scientific data - search engines, social networks, and massive multiuser games also create huge amounts of data.) To convert all the triples into RDF and provide individual links is often unnecessary, and is both time and space intensive. Those looking to do on the

  12. Continuum of haptic space

    NARCIS (Netherlands)

    Kappers, A.M.L.; Koenderink, J.J.

    2002-01-01

    The structure of haptic space has first received serious attention in 1937 by Blumenfeld. Haptic space, as used in this chapter and indeed also by Blumenfeld, involves the space around us which we can reach by touch from a fixed position. How this space is related to the space through which we

  13. Hierarchical Clustering and the Concept of Space Distortion.

    Science.gov (United States)

    Hubert, Lawrence; Schultz, James

    An empirical assesssment of the space distortion properties of two prototypic hierarchical clustering procedures is given in terms of an occupancy model developed from combinatorics. Using one simple example, the single-link and complete-link clustering strategies now in common use in the behavioral sciences are empirically shown to be space…

  14. Space history, space policy, and executive leadership

    Science.gov (United States)

    Kraemer, Sylvia K.

    1993-01-01

    A lecture that attempts to establish the role of space historians in formulating space policy is presented. The discussion focusses on two adages and their relevance to space policy. The adages are as follows: 'write about what you know;' and 'good managers do things right; good executives do the right things.'

  15. Perceptual asymmetries and handedness: A neglected link?

    Directory of Open Access Journals (Sweden)

    Daniele eMarzoli

    2014-02-01

    Full Text Available Healthy individuals tend to weigh in more the left than the right side of visual space in a variety of contexts, ranging from pseudoneglect to perceptual asymmetries for faces. Among the common explanations proposed for the attentional and perceptual advantages of the left visual field, a link with the prevalence of right-handedness in humans has never been suggested, although some evidence seems to converge in favor of a bias of spatial attention towards the region most likely coincident with another person’s right hand during a face-to-face interaction. Such a bias might imply an increased efficiency in monitoring both communicative and aggressive acts, the right limb being more used than the left in both types of behaviour. Although attentional and perceptual asymmetries could be linked to right-handedness at the level of phylogeny because of the evolutionarily advantage of directing attention towards the region where others’ dominant hand usually operates, it is also legitimate to question whether, at the ontogenetic level, frequent exposure to right-handed individuals may foster leftward biases. These views are discussed in the light of extant literature, and a number of tests are proposed in order to assess our hypotheses.

  16. The Creation of Experience Spaces

    DEFF Research Database (Denmark)

    Pedersen, Michael Thyrrestrup

    2013-01-01

    is increasingly sought used as an instrument for attracting people and economy. In the context of Danish cultural policy and planning, the governmental strategy of creating Culture Regions as a means to the goal of creating better cultural offers for people in the region; has led to a new spatial order...... for the theoretical discussions, mainly inspired by Harvey (2009), Brenner (2004) and Mackinnon (2010), to put in to context the relations between national – regional – municipal, in the light of relational space (Massey, 2005) and the quality of place (Healey, 2010). The third space of Soja (1996) will be addressed......-creating production of imaginaries – a primary source for the experience economy. This relational approach to development and to periphery can be seen for example in different niche development projects - linking to discussions on the scale of development and the scale of periphery. The empirical analysis...

  17. Galaxy Gadgeteers: Architects in Space

    Science.gov (United States)

    Morris, M. S.

    This essay explores interdisciplinary themes finding links between architecture, science and science fiction. A character from Douglas Adams' Hitchhiker's Guide series is presented as an archetypical architect charged with designing planets. The author offers diverse examples of other architectural projects dealing with vast planetary and interplanetary scales. The design of space colonies within Dyson Spheres and Torus Rings is examined with an eye to precedents from architectural history. Speculative space colony designs pursued by NASA are critiqued as awkward assemblages of futuristic fantasy and nostalgia. Contemporary architectural projects are presented, revealing the scalar adaptability or looseness of certain architects with strong stylistic tendencies. The paper concludes by examining partly unrealized designs for an Enlightenment utopian town and how themes inspired by the image of the solar system move from spatial and formal arrangements to pictorial and metaphorical depictions.

  18. LinkMind: Link Optimization in Swarming Mobile Sensor Networks

    Directory of Open Access Journals (Sweden)

    Trung Dung Ngo

    2011-08-01

    Full Text Available A swarming mobile sensor network is comprised of a swarm of wirelessly connected mobile robots equipped with various sensors. Such a network can be applied in an uncertain environment for services such as cooperative navigation and exploration, object identification and information gathering. One of the most advantageous properties of the swarming wireless sensor network is that mobile nodes can work cooperatively to organize an ad-hoc network and optimize the network link capacity to maximize the transmission of gathered data from a source to a target. This paper describes a new method of link optimization of swarming mobile sensor networks. The new method is based on combination of the artificial potential force guaranteeing connectivities of the mobile sensor nodes and the max-flow min-cut theorem of graph theory ensuring optimization of the network link capacity. The developed algorithm is demonstrated and evaluated in simulation.

  19. LinkMind: Link Optimization in Swarming Mobile Sensor Networks

    DEFF Research Database (Denmark)

    Ngo, Trung Dung

    2012-01-01

    optimization of swarming mobile sensor networks. The new method is based on combination of the artificial potential force guaranteeing connectivities of the mobile sensor nodes and the max-flow min-cut theorem of graph theory ensuring optimization of the network link capacity. The developed algorithm......A swarming mobile sensor network is comprised of a swarm of wirelessly connected mobile robots equipped with various sensors. Such a network can be applied in an uncertain environment for services such as cooperative navigation and exploration, object identification and information gathering. One...... of the most advantageous properties of the swarming wireless sensor network is that mobile nodes can work cooperatively to organize an ad-hoc network and optimize the network link capacity to maximize the transmission of gathered data from a source to a target. This paper describes a new method of link...

  20. NEW SPACE MECCA

    National Research Council Canada - National Science Library

    Mark Williamson

    2016-01-01

      Five years ago, when the National Aeronautics and Space Administration (NASA) retired the space shuttle fleet and shipped the orbiters to museums across the nation, it seemed that the Kennedy Space Center (KSC...

  1. Fuzzy Hypervector Spaces

    Directory of Open Access Journals (Sweden)

    R. Ameri

    2008-01-01

    Full Text Available The aim of this paper is the generalization of the notion of fuzzy vector spaces to fuzzy hypervector spaces. In this regard, by considering the notion of fuzzy hypervector spaces, we characterized a fuzzy hypervector space based on its level sub-hyperspace. The algebraic nature of fuzzy hypervector space under transformations is studied. Certain conditions are obtained under which a given fuzzy hypervector space can or cannot be realized as a union of two fuzzy hypervector spaces such that none is contained in the other. The construction of a fuzzy hypervector space generated by a given fuzzy subset of a hypervector space is given. The set of all fuzzy cosets of a fuzzy hypervector space is shown to be a hypervector space. Finally, a fuzzy quotient hypervector space is defined and an analogue of a consequence of the “fundamental theorem of homomorphisms” is obtained.

  2. Space Probe Launch

    Science.gov (United States)

    1970-01-01

    Managed by Marshall Space Flight Center, the Space Tug was a reusable multipurpose space vehicle designed to transport payloads to different orbital inclinations. Utilizing mission-specific combinations of its three primary modules (crew, propulsion, and cargo) and a variety of supplementary kits, the Space Tug was capable of numerous space applications. This 1970 artist's concept depicts the Tug's propulsion module launching a space probe into lunar orbit.

  3. Sunspots, Space Weather and Climate

    Science.gov (United States)

    Hathaway, David H.

    2009-01-01

    Four hundred years ago this year the telescope was first used for astronomical observations. Within a year, Galileo in Italy and Harriot in England reported seeing spots on the surface of the Sun. Yet, it took over 230 years of observations before a Swiss amateur astronomer noticed that the sunspots increased and decreased in number over a period of about 11 years. Within 15 years of this discovery of the sunspot cycle astronomers made the first observations of a flare on the surface of the Sun. In the 150 years since that discovery we have learned much about sunspots, the sunspot cycle, and the Sun s explosive events - solar flares, prominence eruptions and coronal mass ejections that usually accompany the sunspots. These events produce what is called Space Weather. The conditions in space are dramatically affected by these events. Space Weather can damage our satellites, harm our astronauts, and affect our lives here on the surface of planet Earth. Long term changes in the sunspot cycle have been linked to changes in our climate as well. In this public lecture I will give an introduction to sunspots, the sunspot cycle, space weather, and the possible impact of solar variability on our climate.

  4. Direct link paths detection for observed teleconnections in climate networks

    Science.gov (United States)

    Zhou, Dong; Gozolchiani, Avi; Ashkenazy, Yosef; Havlin, Shlomo

    2015-04-01

    Climate networks have been used to describe certain kind of relations between the climate time series of each pair of nodes. However, all these observed relations should include both the direct relation between these nodes and the indirect effects through other nodes, and the direct link patterns of climate networks are still unclear. In this work, we use the normalized cross-correlation to define both positive and negative link strengths, and for this definition we develop a method based on partial correlation to remove the indirect effect from the observed global air temperature network and obtain the direct positive and negative links. The strong direct links can illustrate how a certain climatic mechanism is propagating step by step in both time and space. Particularly, for the observed teleconnections, we can find the dominant paths of direct links between two nodes by finding the directed shortest paths in the direct link network. The spatial and temporal properties of these paths can help us better understand the origin of such teleconnections.

  5. Space Flight Applications of Optical Fiber; 30 Years of Space Flight Success

    Science.gov (United States)

    Ott, Melanie N.

    2010-01-01

    For over thirty years NASA has had success with space flight missions that utilize optical fiber component technology. One of the early environmental characterization experiments that included optical fiber was launched as the Long Duration Exposure Facility in 1978. Since then, multiple missions have launched with optical fiber components that functioned as expected, without failure throughout the mission life. The use of optical fiber in NASA space flight communications links and exploration and science instrumentation is reviewed.

  6. Fix Broken and Redirected Links Using Group Dashboard Link Report

    Science.gov (United States)

    Learn how to use the tools provided by Drupal in the Group Dashboard to find and correct links on your site that are broken (404 and 403 error codes), or that redirect (301 and 302), for example to a homepage rather than the originally intended content.

  7. When He Said Linking, He Really Meant Linking

    Science.gov (United States)

    Chudnov, Daniel

    2009-01-01

    There are many reasons to improve web links, starting with their design. The author tends to think about "design" on the web in terms of two things: (1) graphic/industrial design; and (2) human usability. A nice, clean URI (uniform resource identifier) that does not change, is readable to humans, is amenable to common web behaviors such as…

  8. Heuristic search in robot configuration space using variable metric

    Science.gov (United States)

    Verwer, Ben J. H.

    1987-01-01

    A method to generate obstacle free trajectories for both mobile robots and linked robots is proposed. The approach generates the shortest paths in a configuration space. The metric in the configuration space can be adjusted to obtain a tradeoff between safety and velocity by imposing extra costs on paths near obstacles.

  9. CSI related dynamics and control issues in space robotics

    Science.gov (United States)

    Schmitz, Eric; Ramey, Madison

    1993-01-01

    The research addressed includes: (1) CSI issues in space robotics; (2) control of elastic payloads, which includes 1-DOF example, and 3-DOF harmonic drive arm with elastic beam; and (3) control of large space arms with elastic links, which includes testbed description, modeling, and experimental implementation of colocated PD and end-point tip position controllers.

  10. Genetics Home Reference: X-linked adrenoleukodystrophy

    Science.gov (United States)

    ... Home Health Conditions X-linked adrenoleukodystrophy X-linked adrenoleukodystrophy Printable PDF Open All Close All Enable Javascript ... view the expand/collapse boxes. Description X-linked adrenoleukodystrophy is a genetic disorder that occurs primarily in ...

  11. Genetics Home Reference: X-linked thrombocytopenia

    Science.gov (United States)

    ... Home Health Conditions X-linked thrombocytopenia X-linked thrombocytopenia Printable PDF Open All Close All Enable Javascript ... view the expand/collapse boxes. Description X-linked thrombocytopenia is a bleeding disorder that primarily affects males. ...

  12. micromap: A Package for Linked Micromaps

    Science.gov (United States)

    The R package micromap is used to create linked micromaps, which display statistical summaries associated with areal units, or polygons. Linked micromaps provide a means to simultaneously summarize and display both statistical and geographic distributions by linking statistical ...

  13. Space Shuttle Underside Astronaut Communications Performance Evaluation

    Science.gov (United States)

    Hwu, Shian U.; Dobbins, Justin A.; Loh, Yin-Chung; Kroll, Quin D.; Sham, Catherine C.

    2005-01-01

    The Space Shuttle Ultra High Frequency (UHF) communications system is planned to provide Radio Frequency (RF) coverage for astronauts working underside of the Space Shuttle Orbiter (SSO) for thermal tile inspection and repairing. This study is to assess the Space Shuttle UHF communication performance for astronauts in the shadow region without line-of-sight (LOS) to the Space Shuttle and Space Station UHF antennas. To insure the RF coverage performance at anticipated astronaut worksites, the link margin between the UHF antennas and Extravehicular Activity (EVA) Astronauts with significant vehicle structure blockage was analyzed. A series of near-field measurements were performed using the NASA/JSC Anechoic Chamber Antenna test facilities. Computational investigations were also performed using the electromagnetic modeling techniques. The computer simulation tool based on the Geometrical Theory of Diffraction (GTD) was used to compute the signal strengths. The signal strength was obtained by computing the reflected and diffracted fields along the propagation paths between the transmitting and receiving antennas. Based on the results obtained in this study, RF coverage for UHF communication links was determined for the anticipated astronaut worksite in the shadow region underneath the Space Shuttle.

  14. Cold-start link prediction in multi-relational networks

    Science.gov (United States)

    Wu, Shun-yao; Zhang, Qi; Wu, Mei

    2017-10-01

    During the last decade, interaction data have accumulated exponentially in many fields and provide a new opportunity for cold start link prediction. It seems necessarily to take full advantages of diversified information. However, correlation between different interactions has to be pre-tested. Therefore, this paper abstracts complex systems as multi-relational networks, and employs latent space network model to extract low-dimensional factors of sub-networks and adopts likelihood ratio test to examine correlation between factors. Then, regression between target sub-networks and correlated auxiliary sub-networks could be established for cold start link prediction. Experiments on 8 bioinformatic data sets validate the effectiveness and potential of our strategy for network correlation analysis and cold-start link prediction.

  15. Artificial ciliary bundles with nano fiber tip links

    CERN Document Server

    Asadnia, Mohsen; Miao, Jianmin; Triantafyllou, Michael

    2015-01-01

    Mechanosensory ciliary bundles in fishes are the inspiration for carefully engineered artificial flow sensors. We report the development of a new class of ultrasensitive MEMS flow sensors that mimic the intricate morphology of the ciliary bundles, including the stereocilia, tip links, and the cupula, and thereby achieve threshold detection limits that match the biological example. An artificial ciliary bundle is achieved by fabricating closely-spaced arrays of polymer micro-pillars with gradiating heights. Tip links that form the fundamental sensing elements are realized through electrospinning aligned PVDF piezoelectric nano-fibers that link the distal tips of the polymer cilia. An optimized synthesis of hyaluronic acid-methacrylic anhydride hydrogel that results in properties close to the biological cupula, together with drop-casting method are used to form the artificial cupula that encapsulates the ciliary bundle. In testing, fluid drag force causes the ciliary bundle to slide, stretching the flexible nan...

  16. Effect of dust storms on FSO communications links

    KAUST Repository

    Esmail, Maged Abdullah

    2017-05-18

    In literature, there is a lake of information about free space optic (FSO) systems\\' performance in arid and semi-arid areas that are prone to frequent dust storms. Therefore, in this paper, we investigate the performance of FSO links under dust storm conditions. We aim to determine the limits and capabilities of such systems in this harsh environment. To achieve this goal, we use some performance metrics including signal-to-noise (SNR) ratio, bit error rate (BER), and channel capacity. The results show that dust is a rough impairment that causes link drop under low visibility range. Moreover, we found that the system performance can be improved by using short segments or multi-hop system. Furthermore, the results show negligible improvement in system performance under dense dust. The comparison of fog and dust impairments show that dust introduces much higher attenuation than fog. Therefore, dust can be considered as the ultimate impairment for FSO links.

  17. Knowledge space theory and union-closed sets conjecture

    Directory of Open Access Journals (Sweden)

    Chatchawan Panraksa

    2016-08-01

    Full Text Available The knowledge space theory provides a framework for knowledge management. One of major problems is to find core information for a body of knowledge. Union closed set conjecture, if true, guarantees that for a given knowledge space, there is an information that is linked to at least half of the knowledge units. This paper deals with a variant problem, where the knowledge space is also a topological space and possibly infinite. We prove that there is a point belonging to as many open sets as of the topological space itself.

  18. STRS SpaceWire FPGA Module

    Science.gov (United States)

    Lux, James P.; Taylor, Gregory H.; Lang, Minh; Stern, Ryan A.

    2011-01-01

    An FPGA module leverages the previous work from Goddard Space Flight Center (GSFC) relating to NASA s Space Telecommunications Radio System (STRS) project. The STRS SpaceWire FPGA Module is written in the Verilog Register Transfer Level (RTL) language, and it encapsulates an unmodified GSFC core (which is written in VHDL). The module has the necessary inputs/outputs (I/Os) and parameters to integrate seamlessly with the SPARC I/O FPGA Interface module (also developed for the STRS operating environment, OE). Software running on the SPARC processor can access the configuration and status registers within the SpaceWire module. This allows software to control and monitor the SpaceWire functions, but it is also used to give software direct access to what is transmitted and received through the link. SpaceWire data characters can be sent/received through the software interface, as well as through the dedicated interface on the GSFC core. Similarly, SpaceWire time codes can be sent/received through the software interface or through a dedicated interface on the core. This innovation is designed for plug-and-play integration in the STRS OE. The SpaceWire module simplifies the interfaces to the GSFC core, and synchronizes all I/O to a single clock. An interrupt output (with optional masking) identifies time-sensitive events within the module. Test modes were added to allow internal loopback of the SpaceWire link and internal loopback of the client-side data interface.

  19. Space Toxicology: Human Health during Space Operations

    Science.gov (United States)

    Khan-Mayberry, Noreen; James, John T.; Tyl, ROchelle; Lam, Chiu-Wing

    2010-01-01

    Space Toxicology is a unique and targeted discipline for spaceflight, space habitation and occupation of celestial bodies including planets, moons and asteroids. Astronaut explorers face distinctive health challenges and limited resources for rescue and medical care during space operation. A central goal of space toxicology is to protect the health of the astronaut by assessing potential chemical exposures during spaceflight and setting safe limits that will protect the astronaut against chemical exposures, in a physiologically altered state. In order to maintain sustained occupation in space on the International Space Station (ISS), toxicological risks must be assessed and managed within the context of isolation continuous exposures, reuse of air and water, limited rescue options, and the need to use highly toxic compounds for propulsion. As we begin to explore other celestial bodies in situ toxicological risks, such as inhalation of reactive mineral dusts, must also be managed.

  20. Space weather: European Space Agency perspectives

    Science.gov (United States)

    Daly, E. J.; Hilgers, A.

    Spacecraft and payloads have become steadily more sophisticated and therefore more susceptible to space weather effects. ESA has long been active in applying models and tools to the problems associated with such effects on its spacecraft. In parallel, ESA and European agencies have built a highly successful solar-terrestrial physics capability. ESA is now investigating the marriage of these technological and scientific capabilities to address perceived user needs for space weather products and services. Two major ESA-sponsored studies are laying the groundwork for a possible operational European space weather service. The wide-ranging activities of ESA in the Space Weather/Space Environment domain are summarized and recent important examples of space weather concerns given.

  1. Numerical study on the modification of long links in eccentrically braced frame

    Science.gov (United States)

    Musbar, Budiono, Bambang; Kusumastuti, Dyah; Setio, Herlien D.

    2017-11-01

    In anticipating damages to buildings caused by earthquakes, many types of building constructions have been developed and studied. One of these is eccentrically braced frames that uses the link element as part of the structural element that serves to absorb seismic energy. When tested for its ductility, strength, rigidity and energy absorption, the long link performed more poorly compared to short ones. However, advantages of using long links includes space for architectural design and the ease of meeting building requirements. The focus of this study is to provide information on using supplemental double stiffeners on both sides of the web at the ends of long links. The behavior of long links is maintained by positioning the flange failures at the end of the link. The supplemental double stiffeners can improve performance of the long link due to the extension of the inelastic zone and the slowing of failure in the flange at both ends of the link. A numerical study was carried out on several specimens of the long link consisting of a standard specimen and specimens modified by the addition of supplemental double stiffeners. Long link specimens were modified by varying the thickness and hole width on the supplemental double stiffeners. The results showed that the addition of double stiffeners can improve the performance of long links compared to the standard link according to the requirements of AISC 341-10.

  2. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... projects/learn-link-drugs-hiv . 120x90 460x80 486x60 Social Media Send the message to young people and ... Daytona Beach Film Festival Big Mini Film Festival Visual AIDS Bus Boys and Poets Sistahs Getting Real ...

  3. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... the News NIDA Notes Podcasts E-Newsletters Public Education Projects Contact the Press Office Meetings & Events Media ... found at USA.gov . Home » News & Events » Public Education Projects » Learn the Link - Drugs and HIV Learn ...

  4. Drugs + HIV, Learn the Link

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    Full Text Available ... projects/learn-link-drugs-hiv . 120x90 460x80 486x60 Social Media Send the message to young people and to ... available for your use to share on your social media accounts. About the Campaign Overview The Learn the ...

  5. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... projects/learn-link-drugs-hiv . 120x90 460x80 486x60 Social Media Send the message to young people and ... Commission on AIDS Metro Teen Aids Azteca America Foundation/Vive Sin Drogras AdCouncil DC Department of Health ...

  6. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... and HIV/AIDS and the discovery of promising treatment interventions for breaking the harmful links between them, we will continue to update this Web site. Sincerely, Nora D. Volkow, M.D. Director National Institute on Drug Abuse Collaborators Thanks to Those Who Have Helped Raise ...

  7. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... States. Drugs can change the way the brain works, disrupting the parts of the brain that people use to weigh risks and benefits when making decisions. This page connects you to information about the link between drug abuse and HIV infection. It contains information for young ...

  8. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... M.C. et al. “Methamphetamine increases brain viral load and activates natural killer cells in simian immunodeficiency ... at: http://www.drugabuse.gov/news-events/public-education-projects/learn-link-drugs-hiv . 120x90 460x80 486x60 ...

  9. Seismic link at plate boundary

    Indian Academy of Sciences (India)

    ... tested using the coherence of time series to determine the causality and related orientation. The resulting link orientations at the plate boundary conditions indicate that causal triggering seems to be localized along a major fault, as a stress transfer between two major faults, and parallel to the geothermal area extension.

  10. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... link between non-injection drug use and HIV. Television Networks: MunDos Azteca America Univision Telemundo Galavision Telefutura CW BET NBC ABC FOX LATV My Network TV Organizations: AIDS.gov AIDS Alliance for Children, Youth and Families The American Academy of Child & ...

  11. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... with NIDA : Facebook LinkedIn Twitter YouTube Flickr RSS Menu Home Drugs of Abuse Commonly Abused Drugs Charts ... x 5 (PDF, 212KB) Small (PDF, 451 KB) Color 7 x 10 (PDF, 717KB) 7 x 5 ( ...

  12. Drugs + HIV, Learn the Link

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    Full Text Available ... with NIDA : Facebook LinkedIn Twitter YouTube Flickr RSS Menu Home Drugs of Abuse Commonly Abused Drugs Charts ... Daytona Beach Film Festival Big Mini Film Festival Visual AIDS Bus Boys and Poets Sistahs Getting Real ...

  13. Drugs + HIV, Learn the Link

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    Full Text Available ... in recent years, HIV is no longer a death sentence, as it was when the epidemic began. ... at: http://www.drugabuse.gov/news-events/public-education-projects/learn-link-drugs-hiv . 120x90 460x80 486x60 ...

  14. Drugs + HIV, Learn the Link

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    Full Text Available ... Tobacco/Nicotine and E-Cigs Other Drugs Related Topics Addiction Science Adolescent Brain Comorbidity College-Age & Young ... parties or hanging out with friends? It’s a topic you can’t ignore. Learn the Link: http:// ...

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  16. Drugs + HIV, Learn the Link

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  17. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... GA: CDC, DHHS. Retrieved June 2012 How are Drug Abuse and HIV Related? Drug abuse and addiction have been linked with HIV/AIDS ... in this regard, the role that non-injection drug abuse plays in the spread of HIV is less ...

  18. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... the News NIDA Notes Podcasts E-Newsletters Public Education Projects Contact the Press Office Meetings & Events Media ... Plan Search Share Print Home » News & Events » Public Education Projects » Learn the Link - Drugs and HIV Learn ...

  19. Drugs + HIV, Learn the Link

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    Full Text Available ... projects/learn-link-drugs-hiv . 120x90 460x80 486x60 Social Media Send the message to young people and ... gov/1kSfBiz ​ Mention your friends, colleagues, or other organizations in your tweets to spread the word even ...

  20. Drugs + HIV, Learn the Link

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    Full Text Available ... projects/learn-link-drugs-hiv . 120x90 460x80 486x60 Social Media Send the message to young people and ... groups of young people, guiding the use of technology, the discussion between friends, and the importance of ...

  1. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... blood cell that is crucial to the normal function of the human immune system. Loss of these ... at: http://www.drugabuse.gov/news-events/public-education-projects/learn-link-drugs-hiv . 120x90 460x80 486x60 ...

  2. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... no cure, at the present time. The virus (HIV) and the disease it causes (AIDS) are often linked and referred ... an important role in providing current information on HIV/AIDS and related diseases, counseling and testing services, and referrals for medical ...

  3. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Color (PDF, 2.3 MB) Black and White (PDF, 1.1 MB) Web Banner We have created animated Web banner ads that you can download and add to your Web site. Please link these banners back to this site at: http://www. ...

  4. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... projects/learn-link-drugs-hiv . 120x90 460x80 486x60 Social Media Send the message to young people and ... following television networks, organizations, educational institutions, magazines, newspapers, companies, events, and radio stations for helping to raise ...

  5. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... young people and to parents, teachers, and the media about the link between drug misuse and HIV. We have produced a set of multicultural public service announcements (PSAs) that use text messaging as a means of communication. The "Text Message" PSA features two young girls ...

  6. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Researchers Medical & Health Professionals Patients & Families Parents & Educators Children & Teens Search Connect with NIDA : Facebook LinkedIn Twitter YouTube Flickr RSS Menu Home Drugs of Abuse Commonly Abused Drugs Charts Emerging Trends and Alerts Alcohol Club ...

  7. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... with HIV is a key predictor of the development of AIDS. Because of their compromised immune system, ... at: http://www.drugabuse.gov/news-events/public-education-projects/learn-link-drugs-hiv . 120x90 460x80 486x60 ...

  8. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Drug use disorder treatment programs also serve an important role in providing current information on HIV/AIDS ... at: http://www.drugabuse.gov/news-events/public-education-projects/learn-link-drugs-hiv . 120x90 460x80 486x60 ...

  9. X-linked Alport syndrome

    DEFF Research Database (Denmark)

    Jais, Jean Philippe; Knebelmann, Bertrand; Giatras, Iannis

    2003-01-01

    Alport syndrome (AS) is a type IV collagen hereditary disease characterized by progressive hematuric nephritis, hearing loss, and ocular changes. Mutations in the COL4A5 collagen gene are responsible for the more common X-linked dominant form of the disease characterized by much less severe disea...

  10. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... and Drugs Publications Search Publications Orderable DrugFacts Research Reports Mind Over Matter Science of Addiction Funding Funding ... transmitting HIV/AIDS or other infectious diseases. Research Reports: HIV/AIDS : Explores the link between drug misuse ...

  11. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... HIV to their babies during pregnancy, delivery, and breastfeeding. HIV destroys a certain kind of white blood ... at: http://www.drugabuse.gov/news-events/public-education-projects/learn-link-drugs-hiv . 120x90 460x80 486x60 ...

  12. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... the amount of HIV in brain cells 1 . Drug abuse treatment. Since the late 1980s, research has shown that ... we learn more about the critical connection between drug abuse and HIV/AIDS and the discovery of promising treatment interventions for breaking the harmful links between them, ...

  13. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Badges Other Resources Strategic Plan Search Share Print Home » News & Events » Public Education Projects » Learn the Link - Drugs and HIV Learn ... Service Announcements Other Government Observances for Substance Abuse Education Contact the Press Office Meetings & Events Media Guide ... NIDA Home Site Map Accessibility Privacy FOIA(NIH) Working at ...

  14. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... she went to a party and under the influence of drugs and alcohol engaged in risky sexual ... learn-link-drugs-hiv . 120x90 460x80 486x60 Social Media Send the message to young people and to ...

  15. What is Linked Historical Data?

    NARCIS (Netherlands)

    Meroño-Peñuela, A.; Hoekstra, R.; Janowicz, K.; Schlobach, S.; Lambrix, P.; Hyvönen, E.

    2014-01-01

    Datasets that represent historical sources are relative newcomers in the Linked Open Data (LOD) cloud. Following the standard LOD practices for publishing historical sources raises several questions: how can we distinguish between RDF graphs of primary and secondary sources? Should we treat archived

  16. What Is Linked Historical Data?

    NARCIS (Netherlands)

    Meroño-Peñuela, Albert; Hoekstra, Rinke; Janowicz, Krzysztof; Schlobach, Stefan; Lambrix, Patrick; Hyvönen, Eero

    2014-01-01

    Datasets that represent historical sources are relative new- comers in the Linked Open Data (LOD) cloud. Following the standard LOD practices for publishing historical sources raises several questions: how can we distinguish between RDF graphs of primary and secondary sources? Should we treat

  17. New links in the family

    NARCIS (Netherlands)

    Marion Duimel; Jos de Haan

    2007-01-01

    Original title: Nieuwe links in het gezin. Virtually all families with teenagers have at least one computer with an Internet connection, often more. Teenagers spend much of their daily lives on the Internet. They use it to communicate with each other, to do their schoolwork, to meet new

  18. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... HIV > Learn the Link campaign. This campaign shows teens and young adults that non-injection drug use and alcohol use can lead to poor ... been with us for three decades now. Today's teens and young adults have never ... of the real risks of drug use for transmitting HIV, and it encourages them ...

  19. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... is a disease of the immune system for which there is treatment, but no cure, at the present time. The virus (HIV) and the disease it causes (AIDS) are often linked and referred to as "HIV/AIDS." ...

  20. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... NIDA Flickr account for images. Share your favorite image! Check out all of our downloads. Show Learn the Link with Videos We have numerous videos on our website that are available for your use to share on your social media accounts. About the Campaign Overview The Learn the ...

  1. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... the Director of the National Institute on Drug Abuse, Dr. Nora D. Volkow. Message from the Director The Link Between HIV/AIDS and Drug Misuse The HIV/AIDS epidemic has been with us for three decades now. Today's teens and young adults have never known a world without it. ...

  2. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Bath Salts) Tobacco/Nicotine and E-Cigs Other Drugs Related Topics Addiction Science Adolescent Brain Comorbidity College-Age & Young Adults ... 2012 How are Drug Abuse and HIV Related? Drug abuse and addiction have been linked with HIV/AIDS since the ...

  3. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... about the critical connection between drug abuse and HIV/AIDS and the discovery of promising treatment interventions for breaking the harmful links between them, we will continue to update this Web site. Sincerely, Nora D. Volkow, M. ...

  4. Link Dependent Adaptive Radio Simulation

    Science.gov (United States)

    2014-06-01

    of Electrical and Computer Engineering Morgan State University ABSTRACT This paper shows the optimized Link Dependent Adaptive Radio (LDAR...Instrumentation (PEO STRI ). 9 9. REFERENCES [1] M. Elrais, B. Mengiste, B. Gautam and E. Dambia, "Variable OFDM Performance on Aeronautical

  5. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available Skip to main content En español Researchers Medical & Health Professionals Patients & Families Parents & Educators Children & Teens Search Connect with NIDA : Facebook LinkedIn Twitter YouTube Flickr RSS Menu Home Drugs of Abuse ...

  6. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Adolescent Brain Comorbidity College-Age & Young Adults Criminal Justice Drugged Driving Drug Testing Drugs and the Brain ... projects/learn-link-drugs-hiv . 120x90 460x80 486x60 Social Media Send the message to young people and ...

  7. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... News NIDA Notes Podcasts E-Newsletters Public Education Projects Contact the Press Office Meetings & Events Media Guide ... Search Share Print Home » News & Events » Public Education Projects » Learn the Link - Drugs and HIV Learn the ...

  8. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available Skip to main content En español Researchers Medical & Health Professionals Patients & Families Parents & Educators Children & Teens Search Connect with NIDA : Facebook LinkedIn Twitter YouTube Flickr RSS Menu Home Drugs of Abuse Commonly Abused Drugs Charts Emerging Trends and Alerts Alcohol ...

  9. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Health Professionals Patients & Families Parents & Educators Children & Teens Search Connect with NIDA : Facebook LinkedIn Twitter YouTube Flickr ... Populations Treatment Trends & Statistics Women and Drugs Publications Search Publications Orderable DrugFacts Research Reports Mind Over Matter ...

  10. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... depict the devastating consequences of compromised judgment and critical thinking that can result from drug use. Young women ... HIV epidemic. As we learn more about the critical connection between drug ... treatment interventions for breaking the harmful links between them, we ...

  11. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... and what to do to counter these trends. Online Resources NIDA for Teens Web site : This Web ... at: http://www.drugabuse.gov/news-events/public-education-projects/learn-link-drugs-hiv . 120x90 460x80 486x60 ...

  12. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... projects/learn-link-drugs-hiv . 120x90 460x80 486x60 Social Media Send the message to young people and ... available for your use to share on your social media accounts. About the Campaign Overview The Learn ...

  13. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... www.cdc.gov/actagainstaids/basics/whatishiv.html ). Atlanta, GA: CDC, DHHS. Retrieved November 2017. How are Drug Misuse and HIV Related? Drug misuse and addiction have been linked with HIV/AIDS since the beginning of the epidemic. Although injection drug use is well known in this ...

  14. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... the Link campaign. This campaign shows teens and young adults that non-injection drug use and alcohol use can lead to poor decision making, which can result in risky sexual behaviors and HIV infection. Although the characters are fictional, ...

  15. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... projects/learn-link-drugs-hiv . 120x90 460x80 486x60 Social Media Send the message to young people and ... NIDA TV PEERx Drugs & Health Blog The NIDA Science Fair Award for Addiction Science USA Science & Engineering ...

  16. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... CDC, DHHS. Retrieved June 2012 How are Drug Abuse and HIV Related? Drug abuse and addiction have been linked with HIV/AIDS ... this regard, the role that non-injection drug abuse plays in the spread of HIV is less ...

  17. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... message to America's youth that using drugs and alcohol even once can have serious health consequences. We also work to reach parents and ... Drug & Alcohol Facts Week NIDA TV PEERx Drugs & Health Blog The NIDA ... Festival Drug & Alcohol Chat Day HBO Addiction Project Learn the Link ...

  18. Knots, Links and 4-Manifolds

    CERN Document Server

    Fintushel, R; Fintushel, Ronald; Stern, Ronald J.

    1996-01-01

    In this paper we investigate the relationship between isotopy classes of knots and links in S^3 and the diffeomorphism types of homeomorphic smooth 4-manifolds. As a corollary of this initial investigation, we begin to uncover the surprisingly rich structure of diffeomorphism types of manifolds homeomorphic to the K3 surface.

  19. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... who engage in drug use or high-risk behaviors associated with drug use also put themselves at risk for contracting or transmitting HIV/AIDS or other infectious diseases. Research Reports: HIV/AIDS : Explores the link between drug ...

  20. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... HIV/AIDS, and the general public. U.S. National Library of Medicine HIV/AIDS Information : Specialized Information Services. ... this site at: http://www.drugabuse.gov/news-events/public-education-projects/learn-link-drugs-hiv . 120x90 ...

  1. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... learn-link-drugs-hiv . 120x90 460x80 486x60 Social Media Send the message to young people and to ... groups of young people, guiding the use of technology, the discussion between friends, and the importance of ...

  2. Drugs + HIV, Learn the Link

    Medline Plus

    Full Text Available ... Send the Message . Get the Facts What are HIV and AIDS? HIV (human immunodeficiency virus) is the virus that ... AIDS) are often linked and referred to as "HIV/AIDS." HIV can be transferred between people if an ...

  3. Cockpit to helmet optical wireless link: prototype hardware demonstration

    Science.gov (United States)

    Watson, M. A.; White, H. J.; Aldridge, N. B.; Lam, J.; Atkinson, R.

    2009-09-01

    This paper describes recent progress in developing a wireless optical link between the fuselage of a cockpit and an aviation helmet. Such a link is desired to replace the physical umbilical cable existing in current cockpit systems, for reasons of potential bandwidth, immunity to EM interference, and freedom from physical constraints within the cockpit. The link concept consists of multiple transmitters embedded in the cockpit fuselage, each sending video (or symbology) data out in a cone of light over free space, which is detected by an array of receivers positioned on the helmet - the data is then sent to the eyepieces or visor of the pilot (after any intermediate processing). The design is such that one of these links is always maintained throughout possible movement of the head. In a recent proof-of-principle demonstration we showed uncompressed, 100 Mbps video data streamed live from the fuselage of a cockpit simulator to an angled cluster of silicon-based receivers mounted on the helmet, via a pair of ~1 Watt free-space lasers operating at 810 nm. Fast Ethernet media converters were used here for convenience and cost. The bespoke optical and electrical link components were developed in close collaboration with suppliers. The system performance arises from: the high dynamic range of the receivers (up to 25 dB), which are equipped with optical antennae to magnify the optical gain; the high power of the lasers; and the switching electronics used to control the signal path on the helmet. Future potential improvements to the technology are discussed, with an indication of wireless link requirements for relevant BAE Systems applications.

  4. Fake weighted projective spaces

    OpenAIRE

    Buczynska, Weronika

    2008-01-01

    We define fake weighted projective spaces as a generalisation of weighted projective spaces. We introduce the notions of fundamental group in codimension 1 and of universal covering in codimension 1. We prove that for every fake weighted projective space its universal cover in codimension 1 is a weighted projective space.

  5. Organic chemistry in space

    Science.gov (United States)

    Johnson, R. D.

    1977-01-01

    Organic cosmochemistry, organic materials in space exploration, and biochemistry of man in space are briefly surveyed. A model of Jupiter's atmosphere is considered, and the search for organic molecules in the solar system and in interstellar space is discussed. Materials and analytical techniques relevant to space exploration are indicated, and the blood and urine analyses performed on Skylab are described.

  6. Space Guidelines for Libraries.

    Science.gov (United States)

    Wisconsin Coordinating Committee for Higher Education, Madison.

    The following guidelines are recommended: stack space--for each 10 volumes, one square foot of space; reading room--25 square feet per station x 20% of the total undergraduate population; carrel space--25% of the graduate enrollment x 45 square feet; office and auxilliary space--135 square feet x full time equivalent staff. (NI)

  7. Neutrosophic triplet normed space

    Science.gov (United States)

    Şahin, Mehmet; Kargın, Abdullah

    2017-11-01

    In this paper; new properties for neutrosophic triplet groups are introduced. A notion of neutrosophic triplet metric space is given and properties of neutrosophic triplet metric spaces are studied. Neutrosophic triplet vector space and neutrosophic triplet normed space are also studied and some of their properties are given. Furthermore, we also show that these neutrosophic triplet notionsare different from the classical notions.

  8. Budgeting Academic Space

    Science.gov (United States)

    Harris, Watson

    2011-01-01

    There are many articles about space management, including those that discuss space calculations, metrics, and categories. Fewer articles discuss the space budgeting processes used by administrators to allocate space. The author attempts to fill this void by discussing her administrative experiences with Middle Tennessee State University's (MTSU)…

  9. Space Physiology and Operational Space Medicine

    Science.gov (United States)

    Scheuring, Richard A.

    2009-01-01

    The objectives of this slide presentation are to teach a level of familiarity with: the effects of short and long duration space flight on the human body, the major medical concerns regarding future long duration missions, the environmental issues that have potential medical impact on the crew, the role and capabilities of the Space Medicine Flight Surgeon and the environmental impacts experienced by the Apollo crews. The main physiological effects of space flight on the human body reviewed in this presentation are: space motion sickness (SMS), neurovestibular, cardiovascular, musculoskeletal, immune/hematopoietic system and behavioral/psycho-social. Some countermeasures are discussed to these effects.

  10. Wireless Energy and Information Transmission in FSO and RF-FSO Links

    KAUST Repository

    Makki, Behrooz

    2017-09-22

    We propose and analyze a wireless energy and information transmission scheme in free-space optical (FSO) links. The results are presented for both quasi-static and fast-fading conditions. We derive closed-form expressions for throughput, outage probability and optimal power allocation optimizing the system throughput/outage probability. Finally, we complement the FSO link with an additional radio frequency (RF) link to create a hybrid RF-FSO system and reduce the system outage probability. The results show that joint implementation of the RF and FSO links leads to considerable performance improvement, compared to the cases with only FSO-based communication.

  11. Theory of function spaces

    CERN Document Server

    Triebel, Hans

    1983-01-01

    The book deals with the two scales Bsp,q and Fsp,q of spaces of distributions, where -8spaces, such as Hölder spaces, Zygmund classes, Sobolev spaces, Besov spaces, Bessel-potential spaces, Hardy spaces and spaces of BMO-type. It is the main aim of this book to give a unified treatment of the corresponding spaces on the Euclidean n-space Rn in the framework of Fourier analysis, which is based on the technique of maximal functions, Fourier multipliers and interpolation assertions. These topics are treated in Chapter 2, which is the heart

  12. National Space Agencies vs. Commercial Space: Towards Improved Space Safety

    Science.gov (United States)

    Pelton, J.

    2013-09-01

    Traditional space policies as developed at the national level includes many elements but they are most typically driven by economic and political objectives. Legislatively administered programs apportion limited public funds to achieve "gains" that can involve employment, stimulus to the economy, national defense or other advancements. Yet political advantage is seldom far from the picture.Within the context of traditional space policies, safety issues cannot truly be described as "afterthoughts", but they are usually, at best, a secondary or even tertiary consideration. "Space safety" is often simply assumed to be "in there" somewhere. The current key question is can "safety and risk minimization", within new commercial space programs actually be elevated in importance and effectively be "designed in" at the outset. This has long been the case with commercial aviation and there is at least reasonable hope that this could also be the case for the commercial space industry in coming years. The cooperative role that the insurance industry has now played for centuries in the shipping industry and for decades in aviation can perhaps now play a constructive role in risk minimization in the commercial space domain as well. This paper begins by examining two historical case studies in the context of traditional national space policy development to see how major space policy decisions involving "manned space programs" have given undue primacy to "political considerations" over "safety" and other factors. The specific case histories examined here include first the decision to undertake the Space Shuttle Program (i.e. 1970-1972) and the second is the International Space Station. In both cases the key and overarching decisions were driven by political, schedule and cost considerations, and safety seems absence as a prime consideration. In publicly funded space programs—whether in the United States, Europe, Russia, Japan, China, India or elsewhere—it seems realistic to

  13. Space Sciences Focus Area

    Energy Technology Data Exchange (ETDEWEB)

    Reeves, Geoffrey D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-08-10

    To advance our understanding of the space environment (from the Sun to the Earth and beyond) and to advance our ability to operate systems in space that protect life and society. Space Science is distinct from other field, such as astrophysics or cosmology, in that Space Science utilizes in-situ measurements from high altitude rockets, balloons and spacecraft or ground-based measurements of objects and conditions in space.

  14. A Science Strategy for Space Physics

    Science.gov (United States)

    1995-01-01

    This report by the Committee on Solar and Space Physics and the Committee on Solar-Terrestrial Research recommends the major directions for scientific research in space physics for the coming decade. As a field of science, space physics has passed through the stage of simply looking to see what is out beyond Earth's atmosphere. It has become a 'hard' science, focusing on understanding the fundamental interactions between charged particles, electromagnetic fields, and gases in the natural laboratory consisting of the galaxy, the Sun, the heliosphere, and planetary magnetospheres, ionospheres, and upper atmospheres. The motivation for space physics research goes far beyond basic physics and intellectual curiosity, however, because long-term variations in the brightness of the Sun virtually affect the habitability of the Earth, while sudden rearrangements of magnetic fields above the solar surface can have profound effects on the delicate balance of the forces that shape our environment in space and on the human technology that is sensitive to that balance. The several subfields of space physics share the following objectives: to understand the fundamental laws or processes of nature as they apply to space plasmas and rarefied gases both on the microscale and in the larger complex systems that constitute the domain of space physics; to understand the links between changes in the Sun and the resulting effects at the Earth, with the eventual goal of predicting the significant effects on the terrestrial environment; and to continue the exploration and description of the plasmas and rarefied gases in the solar system.

  15. Underground space planning in Helsinki

    Directory of Open Access Journals (Sweden)

    Ilkka Vähäaho

    2014-10-01

    Full Text Available This paper gives insight into the use of underground space in Helsinki, Finland. The city has an underground master plan (UMP for its whole municipal area, not only for certain parts of the city. Further, the decision-making history of the UMP is described step-by-step. Some examples of underground space use in other cities are also given. The focus of this paper is on the sustainability issues related to urban underground space use, including its contribution to an environmentally sustainable and aesthetically acceptable landscape, anticipated structural longevity and maintaining the opportunity for urban development by future generations. Underground planning enhances overall safety and economy efficiency. The need for underground space use in city areas has grown rapidly since the 21st century; at the same time, the necessity to control construction work has also increased. The UMP of Helsinki reserves designated space for public and private utilities in various underground areas of bedrock over the long term. The plan also provides the framework for managing and controlling the city's underground construction work and allows suitable locations to be allocated for underground facilities. Tampere, the third most populated city in Finland and the biggest inland city in the Nordic countries, is also a good example of a city that is taking steps to utilise underground resources. Oulu, the capital city of northern Finland, has also started to ‘go underground’. An example of the possibility to combine two cities by an 80-km subsea tunnel is also discussed. A new fixed link would generate huge potential for the capital areas of Finland and Estonia to become a real Helsinki-Tallinn twin city.

  16. Space Syntax: a method to measure urban space related to social, economic and cognitive factors

    NARCIS (Netherlands)

    van Nes, Akkelies; Yamu, Claudia; Yamu, Claudia; Poplin, Alenka; Devisch, Oswald; De Roo, Gert

    2017-01-01

    Configurational analysis represented by the method of space syntax allows the modelling of a city that links intuition and science, and it can be used for designing and planning cities, as well as in research (Hillier 2009). Developed by Bill Hillier and his colleagues at the University College

  17. Link-topic model for biomedical abbreviation disambiguation.

    Science.gov (United States)

    Kim, Seonho; Yoon, Juntae

    2015-02-01

    unigrams and semantically associated bigrams simultaneously. The addition of semantic links improves the disambiguation accuracy without removing irrelevant contextual words and reduces the parameter space of massive skipping or consecutive bigrams. The link topic model achieves 98.42% disambiguation accuracy on 73,505 MEDLINE abstracts with respect to 21 three letter abbreviations and their 139 distinct long forms. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. SpaceTech—Postgraduate space education

    Science.gov (United States)

    de Bruijn, Ferdi J.; Ashford, Edward W.; Larson, Wiley J.

    2008-07-01

    SpaceTech is a postgraduate program geared primarily for mid-career space professionals seeking to gain or improve their expertise in space systems engineering and in business engineering. SpaceTech provides a lifelong impact on its participants by broadening their capabilities, encouraging systematic "end-to-end" thinking and preparing them for any technical or business-related engineering challenges they may encounter. This flexible 1-year program offers high competency gain and increased business skills. It is held in attractive locations in a flexible, multi-cultural environment. SpaceTech is a highly effective master's program certified by the esteemed Technical University of Delft (TUD), Netherlands. SpaceTech provides expert instructors who place no barriers between themselves and participants. The program combines innovative and flexible new approaches with time-tested methods to give participants the skills required for future missions and new business, while allowing participants to meet their work commitments at the same time as they study for their master's degree. The SpaceTech program is conducted in separate sessions, generally each of 2-week duration, separated by periods of some 6-8 weeks, during which time participants may return to their normal jobs. It also includes introductory online course material that the participants can study at their leisure. The first session is held at the TUD, with subsequent sessions held at strategic space agency locations. By participating at two or more of these sessions, attendees can earn certificates of satisfactory completion from TU Delft. By participating in all of the sessions, as well as taking part in the companion Central Case Project (CCP), participants earn an accredited and highly respected master's degree in Space Systems Engineering from the TUD. Seven distinct SpaceTech modules are provided during these sessions: Space Mission Analysis and Design, Systems Engineering, Business Engineering

  19. Products of straight spaces with compact spaces

    Directory of Open Access Journals (Sweden)

    Kusuo Nishijima

    2007-10-01

    Full Text Available A metric space X is called straight if any continuous real-valued function which is uniformly continuous on each set of a finite cover of X by closed sets, is itself uniformly continuous. Let C be the convergent sequence {1/n : n ϵ N} with its limit 0 in the real line with the usual metric. In this paper, we show that for a straight space X, X × C is straight if and only if X × K is straight for any compact metric space K. Furthermore, we show that for a straight space X, if X × C is straight, then X is precompact. Note that the notion of straightness depends on the metric on X. Indeed, since the real line R with the usual metric is not precompact, R×C is not straight. On the other hand, we show that the product space of an open interval and C is straight.

  20. Section 2: The Space of Media Space

    Science.gov (United States)

    Harrison, Steve

    We began our study of media space with the social aspects of mediated communication because many in the computer-supported cooperative work (CSCW) realm are familiar with models, theories, frameworks, issues, and design approaches related to sociality. But the first media space research came from another set of traditions — the ordering of space and the making of place. Formally, these are the professional and intellectual provinces of architecture, which are probably remote from the disciplinary backgrounds of most readers. However, remoteness in terms of rhetoric and training does not prevent proximity to everyday human experience. The meaning of media space with respect to human experience is the focus of the articles in this section. The spaces are designed to have meaning, and the meaning of the design derives from spatial experience.