WorldWideScience

Sample records for wi north star

  1. 77 FR 55212 - North Star Hydro Services CA, LLC; Notice of Preliminary Permit Application Accepted for Filing...

    Science.gov (United States)

    2012-09-07

    ... Energy Regulatory Commission North Star Hydro Services CA, LLC; Notice of Preliminary Permit Application..., 2012, North Star Hydro Services CA, LLC, Oklahoma, filed an application for a preliminary permit...: David Holland, North Star Hydro Services CA, LLC, 1110 West 131st Street South, Jenks, Oklahoma 74037...

  2. Fairbanks North Star borough rural roads upgrade inventory and cost estimation software user guide : version I.

    Science.gov (United States)

    2013-04-01

    The Rural Road Upgrade Inventory and Cost Estimation Software is designed by the AUTC : research team to help the Fairbanks North Star Borough (FNSB) estimate the cost of upgrading : rural roads located in the Borough's Service Areas. The Software pe...

  3. 77 FR 73651 - North Star Hydro Services, CA LLC; Notice of Preliminary Permit Application Accepted for Filing...

    Science.gov (United States)

    2012-12-11

    ...-000] North Star Hydro Services, CA LLC; Notice of Preliminary Permit Application Accepted for Filing... Star Hydro Services CA, LLC filed an application for a preliminary permit, pursuant to section 4(f) of... generate 5.62 gigawatt-hours annually. Applicant Contact: Mr. David Holland, North Star Hydro Services CA...

  4. Full PWA Report: An Assessment of Energy, Waste, and Productivity Improvements for North Star Steel Iowa

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-06-25

    North Star Steel's Wilton, Iowa plant (NSSI) was awarded a subcontract through a competitive process to use Department of Energy/OIT funding to examine potential processes and technologies that could save energy, reduce waste, and increase productivity.

  5. Evaluation of beach grooming techniques on Escherichia coli density in foreshore sand at North Beach, Racine, WI

    Science.gov (United States)

    Kinzelman, Julie L.; Whitman, Richard L.; Byappanahalli, Muruleedhara N.; Jackson, Emma; Bagley, Robert C.

    2003-01-01

    Elevated levels of Escherichia coli(E. coli) in bathing waters at North Beach, a popular recreational site in Racine, Wisconsin, have been a persistent problem often resulting in the issuance of poor water quality advisories. Moreover, waterfowl (mostly Larus delawarensis and L. argentatus) in nearshore and offshore areas are common and may serve as non-point sources for bacterial contamination of recreational waters. Current beach management practice involves daily mechanical grooming of the nearshore sand for aesthetics and removal of hazardous debris. However, this practice has not been evaluated in terms of its effects on E. coli loading to beach sand and potential introduction to contiguous swimming water. In this study, we tested E. coli responses to three treatments: mechanical groomer, daily and twice weekly hand raking, and a control (no raking/grooming). A randomized block design consisted of replicated treatments and one control (10 each), for a total of 40 blocks sampled daily for 10 days. Foreshore sand samples were collected by hand coring to an average depth of 10 cm. Median E. colirecovered were 73 (mechanically groomed), 27 (hand-raked daily), 32 (hand-raked twice weekly), and 22 (control) colony-forming units (CFU) per gram dry weight sand. E. colicounts in sand that was groomed were significantly higher than hand rakings and control (p management implications related to grooming efficacy and the importance of understanding non-point sources of bacterial contamination.

  6. Evaluation of beach grooming techniques on Escherichia coli density in foreshore sand at North Beach, Racine, WI

    Science.gov (United States)

    Kinzelman, Julie L.; Whitman, Richard L.; Byappanahalli, Muruleedhara N.; Jackson, Emma; Bagley, Robert C.

    2003-01-01

    Elevated levels of Escherichia coli(E. coli) in bathing waters at North Beach, a popular recreational site in Racine, Wisconsin, have been a persistent problem often resulting in the issuance of poor water quality advisories. Moreover, waterfowl (mostly Larus delawarensis and L. argentatus) in nearshore and offshore areas are common and may serve as non-point sources for bacterial contamination of recreational waters. Current beach management practice involves daily mechanical grooming of the nearshore sand for aesthetics and removal of hazardous debris. However, this practice has not been evaluated in terms of its effects on E. coli loading to beach sand and potential introduction to contiguous swimming water. In this study, we tested E. coli responses to three treatments: mechanical groomer, daily and twice weekly hand raking, and a control (no raking/grooming). A randomized block design consisted of replicated treatments and one control (10 each), for a total of 40 blocks sampled daily for 10 days. Foreshore sand samples were collected by hand coring to an average depth of 10 cm. Median E. colirecovered were 73 (mechanically groomed), 27 (hand-raked daily), 32 (hand-raked twice weekly), and 22 (control) colony-forming units (CFU) per gram dry weight sand. E. colicounts in sand that was groomed were significantly higher than hand rakings and control (p grooming efficacy and the importance of understanding non-point sources of bacterial contamination.

  7. Outflows, dusty cores, and a burst of star formation in the North America and Pelican nebulae

    Energy Technology Data Exchange (ETDEWEB)

    Bally, John [Department of Astrophysical and Planetary Sciences, University of Colorado, UCB 389, Boulder, CO 80309 (United States); Ginsburg, Adam [European Southern Observatory, Karl-Schwarzschild-Str. 2, D-85748 Garching bei Munchen (Germany); Probst, Ron [National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States); Reipurth, Bo [Institute for Astronomy and NASA Astrobiology Institute, University of Hawaii at Manoa, 640 North A' ohoku Place, Hilo, HI 96720 (United States); Shirley, Yancy L. [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Stringfellow, Guy S., E-mail: John.Bally@colorado.edu, E-mail: aginsburg@eso.org, E-mail: probst@noao.edu, E-mail: reipurth@ifa.hawaii.edu, E-mail: yshirley@as.arizona.edu, E-mail: Guy.Stringfellow@colorado.edu [Center for Astrophysics and Space Astronomy, University of Colorado, UCB 389, Boulder, CO 80309 (United States)

    2014-12-01

    We present observations of near-infrared 2.12 μm molecular hydrogen outflows emerging from 1.1 mm dust continuum clumps in the North America and Pelican Nebula (NAP) complex selected from the Bolocam Galactic Plane Survey (BGPS). Hundreds of individual shocks powered by over 50 outflows from young stars are identified, indicating that the dusty molecular clumps surrounding the NGC 7000/IC 5070/W80 H II region are among the most active sites of ongoing star formation in the solar vicinity. A spectacular X-shaped outflow, MHO 3400, emerges from a young star system embedded in a dense clump more than a parsec from the ionization front associated with the Pelican Nebula (IC 5070). Suspected to be a binary, the source drives a pair of outflows with orientations differing by 80°. Each flow exhibits S-shaped symmetry and multiple shocks indicating a pulsed and precessing jet. The 'Gulf of Mexico', located south of the North America Nebula (NGC 7000), contains a dense cluster of molecular hydrogen objects (MHOs), Herbig-Haro (HH) objects, and over 300 young stellar objects (YSOs), indicating a recent burst of star formation. The largest outflow detected thus far in the North America and Pelican Nebula complex, the 1.6 parsec long MHO 3417 flow, emerges from a 500 M {sub ☉} BGPS clump and may be powered by a forming massive star. Several prominent outflows such as MHO 3427 appear to be powered by highly embedded YSOs only visible at λ > 70 μm. An 'activity index' formed by dividing the number of shocks by the mass of the cloud containing their source stars is used to estimate the relative evolutionary states of Bolocam clumps. Outflows can be used as indicators of the evolutionary state of clumps detected in millimeter and submillimeter dust continuum surveys.

  8. SeaWiFS_L3b_SCWI_RRS

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  9. SeaWiFS_L3b_SCSU_PAR

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  10. SeaWiFS_L3b_DAY_POC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  11. SeaWiFS_L3b_SNSP_RRS

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  12. SeaWiFS_L3b_CU_CHL

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  13. SeaWiFS_L3b_SNWI_CHL

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  14. SeaWiFS_L3b_DAY_LAND

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  15. SeaWiFS_L3b_CU_CDOM

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  16. SeaWiFS_L3b_SCAU_LAND

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  17. SeaWiFS_L3b_SCSU_CDOM

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  18. SeaWiFS_L3b_SCWI_CHL

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  19. SeaWiFS_L3b_MC_POC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  20. SeaWiFS_L3b_CU_PIC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  1. SeaWiFS_L3b_SCWI_LAND

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  2. SeaWiFS_L3b_SNAU_CDOM

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  3. SeaWiFS_L3b_SCSP_CDOM

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  4. SeaWiFS_L3b_DAY_RRS

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  5. SeaWiFS_L3b_SNWI_RRS

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  6. SeaWiFS_L3b_SCSP_RRS

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  7. SeaWiFS_L3b_DAY_CDOM

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  8. SeaWiFS_L3b_WC_PIC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  9. SeaWiFS_L3b_WC_POC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  10. SeaWiFS_L3b_SNWI_LAND

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  11. SeaWiFS_L3b_SCSU_CHL

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  12. SeaWiFS_L3b_SCSP_PAR

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  13. SeaWiFS_L3b_SCSU_PIC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  14. SeaWiFS_L3b_MO_CHL

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  15. SeaWiFS_L3b_SCSP_POC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  16. SeaWiFS_L3b_MC_CHL

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  17. SeaWiFS_L3b_MO_PIC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  18. SeaWiFS_L3b_MC_RRS

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  19. SeaWiFS_L3b_SNAU_POC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  20. SeaWiFS_L3b_SNSP_POC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  1. SeaWiFS_L3b_SNWI_CDOM

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  2. SeaWiFS_L3b_CU_LAND

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  3. SeaWiFS_L3b_MO_PAR

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  4. NEW NEIGHBORS: PARALLAXES OF 18 NEARBY STARS SELECTED FROM THE LSPM-NORTH CATALOG

    International Nuclear Information System (INIS)

    Lepine, Sebastien; Shara, Michael M.; Thorstensen, John R.; Rich, R. Michael

    2009-01-01

    We present astrometric parallaxes for 18 suspected nearby stars selected from the LSPM-north proper motion catalog. 16 objects are confirmed to be main-sequence M dwarfs within 16 pc of the Sun, including three stars (LSPM J0011+5908, LSPM J0330+5413, and LSPM J0510+2714) which lie just within the 10 pc horizon. Two other targets (LSPM J1817+1328, LSPM J2325+1403) are confirmed to be nearby white dwarfs at distances of 14 and 22 pc, respectively. One of our targets, the common proper motion pair LSPM J0405+7116E + LSPM J0405+7116W, is revealed to be a triple system, with the western component resolved into a pair of 16th magnitude stars (LSPM J0405+7116W-A and LSPM J0405+7116W-B) with a 0.7 ±0.''1 angular separation. We find two stars (LSPM J1314+1320 and LSPM J1757+7042) to be significantly overluminous for their colors, and conclude that these may be unresolved doubles/multiples.

  5. Stars

    CERN Document Server

    Hansen, Grace

    2017-01-01

    This title will cover how stars form, different types of stars, their lifecycle, and the most important star to us--the Sun! Aligned to Common Core Standards and correlated to state standards. Abdo Kids Jumbo is an imprint of Abdo Kids, a division of ABDO.

  6. Elvis to Eminem: quantifying the price of fame through early mortality of European and North American rock and pop stars.

    Science.gov (United States)

    Bellis, Mark A; Hennell, Tom; Lushey, Clare; Hughes, Karen; Tocque, Karen; Ashton, John R

    2007-10-01

    Rock and pop stars are frequently characterised as indulging in high-risk behaviours, with high-profile deaths amongst such musicians creating an impression of premature mortality. However, studies to date have not quantified differences between mortality experienced by such stars and general populations. This study measures survival rates of famous musicians (n = 1064) from their point of fame and compares them to matched general populations in North America and Europe. We describe and utilise a novel actuarial survival methodology which allows quantification of excess post-fame mortality in pop stars. Individuals from North America and Europe performing on any album in the All-Time Top 1000 albums from the music genres rock, punk, rap, R&B, electronica and new age. From 3 to 25 years post fame, both North American and European pop stars experience significantly higher mortality (more than 1.7 times) than demographically matched populations in the USA and UK, respectively. After 25 years of fame, relative mortality in European (but not North American) pop stars begins to return to population levels. Five-year post-fame survival rates suggest differential mortality between stars and general populations was greater in those reaching fame before 1980. Pop stars can suffer high levels of stress in environments where alcohol and drugs are widely available, leading to health-damaging risk behaviour. However, their behaviour can also influence would-be stars and devoted fans. Collaborations between health and music industries should focus on improving both pop star health and their image as role models to wider populations.

  7. Stars

    CERN Document Server

    Kukla, Lauren

    2016-01-01

    Climb Aboard! Explore planets and how they are formed! Meet key astronomers! Examine the history of mapping the stars! Investigate red giants, black and white dwarfs, neutron stars, supernovas, and black holes! See an infographic showing our solar system's statistics! Did You Know? facts and a Guidebook of the brightest stars complete your journey. Aligned to Common Core standards and correlated to state standards. Checkerboard Library is an imprint of Abdo Publishing, a division of ABDO.

  8. 78 FR 44596 - Notice of Inventory Completion: State Historical Society of Wisconsin, Madison, WI

    Science.gov (United States)

    2013-07-24

    ... address in this notice by August 23, 2013. ADDRESSES: Jennifer Kolb, Wisconsin Historical Museum, 30 North Carroll Street, Madison, WI 53703, telephone (608) 261-2461, email Jennifer.Kolb@wisconsinhistory.org... request to Jennifer Kolb, Wisconsin Historical Museum, 30 North Carroll Street, Madison, WI 53703...

  9. WiMAX-WiFi convergence with OFDM bridge

    Science.gov (United States)

    Al-Sherbaz, Ali; Adams, Chris; Jassim, Sabah

    2009-05-01

    Nowadays, Wireless and mobile communications technologies are the most important areas, which are rapidly expanding either in horizontal or vertical directions. WiMAX is trying to compete with WiFi in coverage and data rate, while the inexpensive WiFi still very popular in both personal and business use. Efficient bandwidth usage, Multi-Standard convergence and Wireless Mesh Networks (WMN) are the main vertical tends in the wireless world. WiMAX-WiFi convergence as an ideal technology that provides the best of both worlds: WiMAX new features and the low cost of the WiFi. In order to create a heterogeneous network environment, differences between the two technologies have been investigated and resolved. In the Multi-Carrier WiMAX-WiFi Convergence, the mismatch between the fixed WiMAXOFDM (Nfft=256) and the WiFi-OFDM (Nfft=64) has been confirmed as a physical layer issue that will never be solved as MAC layer problem; therefore the current proposal is how to build what we called the "Convergence-Bridge". This bridge is like an extra thin layer, which is responsible for harmonizing the mismatch. For the WiFi-OFDM physical layer, the paper has selected the IEEE 802.11n OFDM standard while it is being developed. The proposal does not suggest changing the standard itself but modifying some functions to be configurable. The IEEE 802.11 standard has fixed the configurations for WiFi mode only, while our proposal is to set up these functions for WiFi and WiMAX modes.

  10. KiWi Vision

    DEFF Research Database (Denmark)

    Schaffert, Sebastian; Bry, Francois; Dolog, Peter

    This deliverable describes the common vision of the KiWi project, ranging from motivation over use cases and usage scenarios to user interaction, system architecture and technologies, and the research that is performed as part of the project. The deliverable is intended for a wide audience to give...

  11. DIY WiFi

    CERN Document Server

    Jungnickel, Katrina

    2013-01-01

    Who makes WiFi?Why do different makers matter?What do barbeques and backyards have to do with the internet?This book explores how WiFi is made from the ground up, or in this case from the backyard out. Forged around barbeques, made of found, adapted and off-the-shelf materials and installed in ordinary domestic spaces, this book documents the collective work of individuals committed to making 'Ournet not the internet'.Drawing on rich ethnographic material, Jungnickel's research on community WiFi networking provides an overdue account of the innovative digital cultures and practices of ordinary people making extra-ordinary things. What make-do methods, mods and tales of resourceful ingenuity permit is another way of seeing how technologies come into being. It brings to life an Australian version of WiFi, enriching global studies of wireless technology by signalling the potential of comparative studies. Critically, the book presents the first sustained study of homebrew high-tech backyard technologists who imbu...

  12. SeaWiFS_L3m_CU_LAND_NDVI_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  13. SeaWiFS_L3m_MC_CDOM_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  14. SeaWiFS_L3m_SNSP_CHL_chlor_a_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  15. SeaWiFS_L3m_SNSP_CDOM_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  16. SeaWiFS_L3m_WC_POC_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  17. SeaWiFS_L3b_SNSP_KD490

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  18. SeaWiFS_L3m_SCSU_RRS_angstrom_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  19. SeaWiFS_L3m_SCSU_KD490_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  20. SeaWiFS_L3m_SNSP_LAND_NDVI_4km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  1. SeaWiFS_L3m_YR_RRS_aot_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  2. SeaWiFS_L3m_SNAU_CHL_chlor_a_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  3. SeaWiFS_L3m_SCAU_LAND_NDVI_4km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  4. SeaWiFS_L3m_WC_RRS_aot_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  5. SeaWiFS_L3b_8D_LAND

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  6. SeaWiFS_L3m_DAY_RRS_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  7. SeaWiFS_L3m_SNWI_PAR_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  8. SeaWiFS_L3m_SNAU_CDOM_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  9. SeaWiFS_L3b_R32_KD490

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  10. SeaWiFS_L3m_MO_RRS_angstrom_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  11. SeaWiFS_L3b_R32_PIC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  12. SeaWiFS_L3m_MO_CDOM_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  13. SeaWiFS_L3m_8D_RRS_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  14. SeaWiFS_L3m_R32_CHL_chlor_a_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  15. SeaWiFS_L3b_R32_PAR

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  16. SeaWiFS_L3m_8D_KD490_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  17. SeaWiFS_L3b_8D_PIC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  18. SeaWiFS_L3m_R32_RRS_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  19. SeaWiFS_L3m_CU_PAR_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  20. SeaWiFS_L3m_MC_PIC_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  1. SeaWiFS_L3m_SCWI_LAND_NDVI_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  2. SeaWiFS_L3m_SNAU_RRS_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  3. SeaWiFS_L3m_SCSU_LAND_NDVI_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  4. SeaWiFS_L3b_8D_KD490

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  5. SeaWiFS_L3b_R32_RRS

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  6. SeaWiFS_L3m_MO_CHL_chlor_a_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  7. SeaWiFS_L3m_WC_CHL_chlor_a_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  8. SeaWiFS_L3m_WC_KD490_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  9. SeaWiFS_L3m_CU_RRS_aot_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  10. SeaWiFS_L3m_SNSP_RRS_aot_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  11. SeaWiFS_L3m_SNSU_POC_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  12. SeaWiFS_L3m_SNSU_CHL_chlor_a_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  13. SeaWiFS_L3m_SNSP_PIC_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  14. SeaWiFS_L3m_MC_KD490_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  15. SeaWiFS_L3m_8D_POC_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  16. SeaWiFS_L3m_MO_RRS_aot_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  17. SeaWiFS_L3m_R32_PAR_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  18. SeaWiFS_L3m_WC_PIC_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  19. SeaWiFS_L3m_DAY_CDOM_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  20. SeaWiFS_L3m_SCAU_LAND_NDVI_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  1. SeaWiFS_L3b_SNSU_KD490

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  2. SeaWiFS_L3b_MO_KD490

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  3. SeaWiFS_L3m_R32_RRS_aot_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  4. SeaWiFS_L3b_MC_KD490

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  5. SeaWiFS_L3b_8D_POC

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  6. SeaWiFS_L3m_SNSU_CDOM_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  7. SeaWiFS_L3m_SNAU_RRS_aot_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  8. SeaWiFS_L3m_MC_RRS_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  9. SeaWiFS_L3m_SNSP_PAR_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  10. SeaWiFS_L3m_YR_RRS_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  11. SeaWiFS_L3m_SCSP_POC_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  12. SeaWiFS_L3m_DAY_PAR_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  13. SeaWiFS_L3m_YR_CDOM_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  14. SeaWiFS_L3m_R32_LAND_NDVI_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  15. SeaWiFS_L3m_SCSP_PAR_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  16. SeaWiFS_L3m_R32_PIC_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  17. SeaWiFS_L3b_8D_CHL

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  18. SeaWiFS_L3m_SCWI_RRS_aot_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  19. SeaWiFS_L3m_MC_PAR_9km

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS instrument was launched by Orbital Sciences Corporation on the OrbView-2 (a.k.a. SeaStar) satellite in August 1997, and collected data from September...

  20. Sea Star Wasting Disease in Asterias forbesi along the Atlantic Coast of North America.

    Science.gov (United States)

    Bucci, Caitlin; Francoeur, Madison; McGreal, Jillon; Smolowitz, Roxanna; Zazueta-Novoa, Vanesa; Wessel, Gary M; Gomez-Chiarri, Marta

    2017-01-01

    As keystone species, sea stars serve to maintain biodiversity and species distribution through trophic level interactions in marine ecosystems. Recently, Sea Star Wasting Disease (SSWD) has caused widespread mass mortality in several sea star species from the Pacific Coast of the United States of America (USA) and Asterias forbesi on the Atlantic Coast. A densovirus, named Sea Star associated Densovirus (SSaDV), has been associated with the wasting disease in Pacific Coast sea stars, and limited samples of A. forbesi. The goal of this research is to examine the pathogenesis of SSWD in A. forbesi on the Atlantic Coast of the USA and to determine if SSaDV is associated with the wasting disease in this species. Histological examination of A. forbesi tissues affected with SSWD showed cuticle loss, vacuolation and necrosis of epidermal cells, and oedema of the dermis, but no consistent evidence indicating the cause of the lesions. Challenge experiments by cohabitation and immersion in infected water suggest that the cause of SSWD is viral in nature, as filtration (0.22 μm) of water from tanks with sea stars exhibiting SSWD did not prevent the transmission and progression of the disease. Death of challenged sea stars occurred 7-10 d after exposure to infected water or sea stars, and the infectivity crossed species (A. forbesi and Pateria miniata) with equal penetrance. Of the 48 stars tested by quantitative real time PCR, 29 (60%) were positive for the SSaDV VP1 gene. These stars represent field-collected sea stars from all geographical regions (South Carolina to Maine) in 2012-2015, as well as stars exposed to infected stars or water from affected tanks. However, a clear association between the presence of SSaDV and SSWD signs in experimental and field-collected A. forbesi was not found in this study.

  1. Sea Star Wasting Disease in Asterias forbesi along the Atlantic Coast of North America.

    Directory of Open Access Journals (Sweden)

    Caitlin Bucci

    Full Text Available As keystone species, sea stars serve to maintain biodiversity and species distribution through trophic level interactions in marine ecosystems. Recently, Sea Star Wasting Disease (SSWD has caused widespread mass mortality in several sea star species from the Pacific Coast of the United States of America (USA and Asterias forbesi on the Atlantic Coast. A densovirus, named Sea Star associated Densovirus (SSaDV, has been associated with the wasting disease in Pacific Coast sea stars, and limited samples of A. forbesi. The goal of this research is to examine the pathogenesis of SSWD in A. forbesi on the Atlantic Coast of the USA and to determine if SSaDV is associated with the wasting disease in this species. Histological examination of A. forbesi tissues affected with SSWD showed cuticle loss, vacuolation and necrosis of epidermal cells, and oedema of the dermis, but no consistent evidence indicating the cause of the lesions. Challenge experiments by cohabitation and immersion in infected water suggest that the cause of SSWD is viral in nature, as filtration (0.22 μm of water from tanks with sea stars exhibiting SSWD did not prevent the transmission and progression of the disease. Death of challenged sea stars occurred 7-10 d after exposure to infected water or sea stars, and the infectivity crossed species (A. forbesi and Pateria miniata with equal penetrance. Of the 48 stars tested by quantitative real time PCR, 29 (60% were positive for the SSaDV VP1 gene. These stars represent field-collected sea stars from all geographical regions (South Carolina to Maine in 2012-2015, as well as stars exposed to infected stars or water from affected tanks. However, a clear association between the presence of SSaDV and SSWD signs in experimental and field-collected A. forbesi was not found in this study.

  2. The Brightening of the North Star: Has Polaris' Brightness Steadily Increased for Centuries and, perhaps, even Millennia?

    Science.gov (United States)

    Engle, Scott G.; Guinan, E. F.; Harmanec, P.; Božić, H.; Ruzdjak, D.; Sudar, D.

    2014-01-01

    Polaris is arguably the best-known star in the Northern Hemisphere, since it lies within a degree of the North Celestial Pole. For much of human history, Polaris was highly regarded for its unchanging nature. However, we now know that Polaris is a Cepheid variable, undergoing ultra-low-amplitude pulsations. Thirty years ago, a paper in the Astrophysical Journal by A. Arellano Ferro announced that the amplitude of these pulsations was diminishing. This behavior was confirmed, and it was believed that soon enough Polaris would no longer be a Cepheid variable. We started photometrically monitoring Polaris in 1999 and discovered that the amplitude of pulsations had reached a minimum and was now, in fact, growing again. It was while gathering historic photometry for the amplitude study that we noticed the published magnitudes of Polaris were systematically fainter, the further back in time the data went. This is an entirely unexpected behavior for a Cepheid variable, and one that we wanted to investigate further. We continue to observe Polaris to monitor the star's brightness, along with pulsation period and amplitude, and we have re-analyzed the historic studies of Polaris to validate the brightening. We have also obtained HST-COS UV spectra of Polaris for comparison to archival IUE data, to look for flux and/or temperature changes. We gratefully acknowledge support from NASA grant HST-GO-11726.

  3. WiFi and WiMAX Secure Deployments

    Directory of Open Access Journals (Sweden)

    Panagiotis Trimintzios

    2010-01-01

    Full Text Available Wireless Broadband offers incredibly fast, “always on” Internet similar to ADSL and sets the user free from the fixed access areas. In order to achieve these features standardisation was achieved for Wireless LAN (WLANs and Wireless Metropolitan Area Networks (WMANs with the advent of IEEE802.11 and IEEE802.16 family of standards, respectively. One serious concern in the rapidly developing wireless networking market has been the security of the deployments since the information is delivered freely in the air and therefore privacy and integrity of the transmitted information, along with the user-authentication procedures, become a very important issue. In this article, we present the security characteristics for the WiFi and the WiMAX networks. We thoroughly present the security mechanisms along with a threat analysis for both IEEE 802.11 and the 802.16 as well as their amendments. We summarise in a comparative manner the security characteristics and the possible residual threats for both standards. Finally focus on the necessary actions and configurations that are needed in order to deploy WiFi and WiMAX with increased levels of security and privacy.

  4. Wi-Fi/WiGig Coordination for Optimal WiGig Concurrent Transmissions in Random Access Scenario

    OpenAIRE

    Mohamed, Ehab Mahmoud; Sakaguchi, Kei; Sampei, Seiichi

    2016-01-01

    Wireless Gigabit (WiGig) access points (APs) using 60 GHz unlicensed frequency band are considered as key enablers for future Gbps WLANs. Due to its short range transmission with high susceptibility to path blocking, a multiple number of WiGig APs should be installed to fully cover a typical target environment. However, using autonomously operated WiGig APs with IEEE 802.11ad DCF, the exhaustive search analog beamforming and the maximum received power based autonomous users association preven...

  5. Campus Area Network Wi-Fi Security

    Directory of Open Access Journals (Sweden)

    Arjun K. Pillay

    2017-07-01

    Full Text Available Wireless connectivity devices such as mobile phones and laptops are being increasingly used by University students to access learning resources on campus networks and the Internet. Each of the mobile devices offers security protocols for connection to a Wi-Fi router. This paper presents an overview of Wi-Fi security and recommendations in relation to free Wi-Fi service at The University of Fiji.

  6. Hazard Analysis and Disaster Preparedness in the Fairbanks North Star Borough, Alaska using Hazard Simulations, GIS, and Network Analysis

    Science.gov (United States)

    Schaefer, K.; Prakash, A.; Witte, W.

    2011-12-01

    The Fairbanks North Star Borough (FNSB) lies in interior Alaska, an area that is dominated by semiarid, boreal forest climate. FNSB frequently witnesses flooding events, wild land fires, earthquakes, extreme winter storms and other natural and man-made hazards. Being a large 19,065 km2 area, with a population of approximately 97,000 residents, providing emergency services to residents in a timely manner is a challenge. With only four highways going in and out of the borough, and only two of those leading to another city, most residents do not have quick access to a main road. Should a major disaster occur and block one of the two highways, options for evacuating or getting supplies to the area quickly dwindle. We present the design of a Geographic Information System (GIS) and network analysis based decision support tool that we have created for planning and emergency response. This tool will be used by Emergency Service (Fire/EMS), Emergency Management, Hazardous Materials Team, and Law Enforcement Agencies within FNSB to prepare and respond to a variety of potential disasters. The GIS combines available road and address networks from different FNSB agencies with the 2010 census data. We used ESRI's ArcGIS and FEMA's HAZUS-MH software to run multiple disaster scenarios and create several evacuation and response plans. Network analysis resulted in determining response time and classifying the borough by response times to facilitate allocation of emergency resources. The resulting GIS database can be used by any responding agency in FNSB to determine possible evacuation routes, where to open evacuation centers, placement of resources, and emergency response times. We developed a specific emergency response plan for three common scenarios: (i) major wildfire threatening Fairbanks, (ii) a major earthquake, (iii) loss of power during flooding in a flood-prone area. We also combined the network analysis results with high resolution imagery and elevation data to determine

  7. WIRELESS FIDELITY (Wi-Fi) BROADBAND NETWORK ...

    African Journals Online (AJOL)

    ES Obe

    categorized into two types: fixed and mobile wireless. The broadband fixed wireless network technologies .... 3.0 WIRELESS FIDELITYF (Wi-Fi). NETWORK IMPLEMENTATION. A Wi-Fi enabled device such as a PC, game .... Amateur radio, video senders, and cordless phones, can cause significant additional interference.

  8. WI Biodiesel Blending Progream Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Redmond, Maria E; Levy, Megan M

    2013-04-01

    The Wisconsin State Energy Office's (SEO) primary mission is to implement cost effective, reliable, balanced, and environmentally friendly clean energy projects. To support this mission the Wisconsin Biodiesel Blending Program was created to financially support the installation infrastructure necessary to directly sustain biodiesel blending and distribution at petroleum terminal facilities throughout Wisconsin. The SEO secured a federal directed award of $600,000 over 2.25 years. With these funds, the SEO supported the construction of inline biodiesel blending facilities at two petroleum terminals in Wisconsin. The Federal funding provided through the state provided a little less than half of the necessary investment to construct the terminals, with the balance put forth by the partners. Wisconsin is now home to two new biodiesel blending terminals. Fusion Renewables on Jones Island (in the City of Milwaukee) will offer a B100 blend to both bulk and retail customers. CITGO is currently providing a B5 blend to all customers at their Granville, WI terminal north of the City of Milwaukee.

  9. LTE OFFLOADING THROUGH WiFi NETWORKS

    Directory of Open Access Journals (Sweden)

    A. N. Steputin

    2015-11-01

    Full Text Available The subject of the article is Wi-Fi offloading of LTE networks as one of the methods for solving a problem of the lack of availability of network resources in the future. Comparison of mobile networks offloading technologies, such as femtocells, Small Cells and Wi-Fi, is given. Architecture of cooperative LTE+Wi-Fi network including both new network components and new functions for standard LTE network components is presented as well as interaction between components. Special attention is paid to the usage of mobile IP protocols providing connection to the LTE Core both by trusted and untrusted Wi-Fi access. Evaluation of implementation effectiveness and prospective of the technology is given. The relation between amounts of users reconnected to Wi-Fi, data rate of LTE network and amount of access points are submitted as a part of the simulation of user’s equipment transition process from LTE to Wi-Fi network. A conclusion based on the research is made that stepwise phase-in of this technology enables to solve the problem of mobile network resources shortage in metropolises due to permanent traffic growth. It is presented that access points addition and transference of the customers to Wi-Fi network significantly reduce the overload on the base station herewith it increases some data rate with preservation of quality of provided services.

  10. WiMax network planning and optimization

    CERN Document Server

    Zhang, Yan

    2009-01-01

    This book offers a comprehensive explanation on how to dimension, plan, and optimize WiMAX networks. The first part of the text introduces WiMAX networks architecture, physical layer, standard, protocols, security mechanisms, and highly related radio access technologies. It covers system framework, topology, capacity, mobility management, handoff management, congestion control, medium access control (MAC), scheduling, Quality of Service (QoS), and WiMAX mesh networks and security. Enabling easy understanding of key concepts and technologies, the second part presents practical examples and illu

  11. Coexistence of WiFi and WiMAX systems based on PS-request protocols.

    Science.gov (United States)

    Kim, Jongwoo; Park, Suwon; Rhee, Seung Hyong; Choi, Yong-Hoon; Chung, Young-uk; Hwang, Ho Young

    2011-01-01

    We introduce both the coexistence zone within the WiMAX frame structure and a PS-Request protocol for the coexistence of WiFi and WiMAX systems sharing a frequency band. Because we know that the PS-Request protocol has drawbacks, we propose a revised PS-Request protocol to improve the performance. Two PS-Request protocols are based on the time division operation (TDO) of WiFi system and WiMAX system to avoid the mutual interference, and use the vestigial power management (PwrMgt) bit within the Frame Control field of the frames transmitted by a WiFi AP. The performance of the revised PS-Request protocol is evaluated by computer simulation, and compared to those of the cases without a coexistence protocol and to the original PS-Request protocol.

  12. Coexistence of WiFi and WiMAX Systems Based on PS-Request Protocols†

    Science.gov (United States)

    Kim, Jongwoo; Park, Suwon; Rhee, Seung Hyong; Choi, Yong-Hoon; Chung, Young-uk; Hwang, Ho Young

    2011-01-01

    We introduce both the coexistence zone within the WiMAX frame structure and a PS-Request protocol for the coexistence of WiFi and WiMAX systems sharing a frequency band. Because we know that the PS-Request protocol has drawbacks, we propose a revised PS-Request protocol to improve the performance. Two PS-Request protocols are based on the time division operation (TDO) of WiFi system and WiMAX system to avoid the mutual interference, and use the vestigial power management (PwrMgt) bit within the Frame Control field of the frames transmitted by a WiFi AP. The performance of the revised PS-Request protocol is evaluated by computer simulation, and compared to those of the cases without a coexistence protocol and to the original PS-Request protocol. PMID:22163721

  13. WiFi Assisted Multi-WiGig AP Coordination for Future Multi-Gbps WLANs

    OpenAIRE

    Mohamed, Ehab Mahmoud; Kusano, Hideyuki; Sakaguchi, Kei; Sampei, Seiichi

    2015-01-01

    Wireless Gigabit (WiGig) access points (APs) using 60 GHz unlicensed frequency band are considered as key enablers for future Gbps wireless local area networks (WLANs). Exhaustive search analog beamforming (BF) is mainly used with WiGig transmissions to overcome channel propagation loss and accomplish high rate data transmissions. Due to its short range transmission with high susceptibility to path blocking, a multiple number of WiGig APs should be installed to fully cover a typical target en...

  14. Cost Analyses of Measures to Improve Residential Energy Ratings to 6 Stars - Playford North Development, South Australia

    Directory of Open Access Journals (Sweden)

    Timothy O'Leary

    2010-07-01

    Full Text Available  This paper reports the results of a study on the cost implications of achieving greater energy efficiency as measured by House Energy Rating(HER ‘stars’ for new housing on a greenfield development in the northern suburbs of Adelaide. Twelve house designs typical of the housing options available from a number of builders engaged with this development were modeled using the 2nd generation Building Code of Australia (BCA accredited energy rating assessment tool AccuRate. Where the model predicted a rating below the minimum rating (6 star proposed under the recently agreed Commonwealth of Australia, National Energy Efficiency strategy, the designs were modified in order to improve the rating to 6 stars using a combination of specification changes and energy efficient technology options. These changes or options were then priced at prevailing building suppliers and subcontractors retail cost levels in order that an average ‘extra cost to 6 star’ and range of indicative costs to achieve 6 star housing compliance could be articulated. The results revealed that standard and currently available technologies, such a reflective foil barriers, increased insulation and low emissivity ‘e’ type glazing provide a means to achieving 6 star ratings at a modest additional cost, i.e. 1-2% of total construction and development costs.

  15. Indoor Positioning using Wi-Fi

    DEFF Research Database (Denmark)

    Kjærgaard, Mikkel Baun; Krarup, Mads Vering; Stisen, Allan

    The past decade has witnessed substantial research on methods for indoor Wi-Fi positioning. While much effort has gone into achieving high positioning accuracy and easing fingerprint collection, it is our contention that the general problem is not sufficiently well understood, thus preventing...... deployments and their usage by applications to become more widespread. Based on our own and published experiences on indoor Wi-Fi positioning deployments, we hypothesize the following: Current indoor Wi-Fi positioning systems and their utilization in applications are hampered by the lack of understanding...... of the requirements present in the real-world deployments. In this paper, we report findings from qualitatively studying organisational requirements for indoor Wi-Fi positioning. The studied cases and deployments cover both company and public-sector settings and the deployment and evaluation of several types...

  16. Eesti graafikud Krakówi triennaalil

    Index Scriptorium Estoniae

    2009-01-01

    16. septembril Poolas avatud Krakówi rahvusvahelise graafikatriennaali peanäitusel ja satelliitnäitustel esindavad Eestit Eve Kask, Ülle Marks, Benjamin Vasserman, Tiiu Prisko, Mati Veermets, Evi Tihemets

  17. WiMAX technology and network evolution

    CERN Document Server

    Etemad, Kamran

    2010-01-01

    WiMAX, the Worldwide Interoperability for Microwave Access, represents a paradigm shift in telecommunications technology. It offers the promise of cheaper, smaller, and simpler technology compared to existing broadband options such as DSL, cable, fiber, and 3G wireless.

  18. Integrating free-space optical communication links with existing WiFi (WiFO) network

    Science.gov (United States)

    Liverman, S.; Wang, Q.; Chu, Y.; Duong, T.; Nguyen-Huu, D.; Wang, S.; Nguyen, T.; Wang, A. X.

    2016-02-01

    Recently, free-space optical (FSO) systems have generated great interest due to their large bandwidth potential and a line-of-sight physical layer of protection. In this paper, we propose WiFO, a novel hybrid system, FSO downlink and WiFi uplink, which will integrate currently available WiFi infrastructure with inexpensive infrared light emitting diodes. This system takes full advantage of the mobility inherent in WiFi networks while increasing the downlink bandwidth available to each end user. We report the results of our preliminary investigation that show the capabilities of our prototype design in terms of bandwidth, bit error rates, delays and transmission distances.

  19. How much can Wi-Fi offload?

    DEFF Research Database (Denmark)

    Hu, Liang; Coletti, Claudio; Nguyen, Huan Cong

    2012-01-01

    This paper is envisaged to provide a first quantitative study on how much indoor deployed Wi-Fi can offload the operator’s 3G HSPA macro cellular networks in a real largescale dense-urban scenario. Wi-Fi has been perceived as a costeffective mean of adding wireless capacity by leveraging low......-cost access points and unlicensed spectrum. However, the quantitative offloading gain that Wi-Fi can achieve is still unknown. We studied the Wi-Fi offloading gain as a function of access point density, where it is shown that 10 access points/km2 can already boost average user throughput by 300% and the gain...... increases linearly proportional to the access point density. Indoor Wi-Fi deployment also significantly reduces the number of users in outage, especially for indoor area. A user is considered to be in outage if they have a user throughput less than 512 kbps. We also propose three Wi-Fi deployment algorithms...

  20. WiMax taking wireless to the max

    CERN Document Server

    Pareek, Deepak

    2006-01-01

    With market value expected to reach 5 billion by 2007 and the endorsement of some of the biggest names in telecommunications, World Interoperability for Microwave Access (WiMAX) is poised to change the broadband wireless landscape. But how much of WiMAX's touted potential is merely hype? Now that several pre-WiMAX networks have been deployed, what are the operators saying about QoS and ROI? How and when will device manufacturers integrate WiMAX into their products? What is the business case for using WiMAX rather than any number of other established wireless alternatives?WiMAX: Taking Wireless

  1. Personalization Component for KiWi Framework

    DEFF Research Database (Denmark)

    Durao, Frederico; Xu, Guandong; Kotowski, Jakub

    2010-01-01

    . The personalization component is responsible for addressing and delivering information to individuals regarding their roles and preferences, explicitly or implicitly inferred from their activities in the system. Personalization is a essential for KiWi since this in a multi-user environment and individuals has......In this report we present the personalization component implemented for KiWi addressing diverse aspects such as motivation scenarios, configuration management, formal models, implementations and some real case scenarios on how personalization can be applied to support software project management...... different interests and needs when using the system....

  2. ESP8266 WI-FI MODULE FOR MONITORING SYSTEM APPLICATION

    OpenAIRE

    Tae-Gue Oh; Chung-Hyuk Yim; Gyu-Sik Kim

    2017-01-01

    The ESP8266 Wi-Fi module is a self-contained system-on-chip (SOC) with integrated TCP/IP protocol stacks that can give any microcontroller access to a Wi-Fi network. In this paper, the interface between the ESP8266 Wi-Fi module and arduino MCU is studied for monitoring system application. Through some experimental studies, we believe that the ESP8266 Wi-Fi module is very useful for monitoring system application.

  3. ``But I am constant as the North Star*'' - The Return of Polaris as a Low Amplitude Classical Cepheid

    Science.gov (United States)

    Davis, J. J.; Tracey, J. C.; Engle, S. G.; Guinan, E. F.

    2002-12-01

    * Julius Caesar, William Shakespeare Polaris ( ≈ +2.0 mag; B-V = +0.60; F7 Ib) is a low amplitude Classical Cepheid with a pulsation period of P = 3.97 days. Polaris is one of the nearest (dHipparcos = 132 +/- 8 pc) and brightest Cepheid. This Cepheid (Polaris A) is the luminous member of the multiple star system (ADS 1477). Over the last century amazing changing have been occurring for this famous star. The pulsation period has been increasing a rate of dP/dt = +3.2 sec/yr while the light amplitude has decreased from ~0.12 mag (1900s) to ~0.02 mag (early1990s). A recent summary and thorough discussion of Polaris's interesting properties are given by Evans et al. (2002, ApJ, 567, 1121). We have been carrying out photoelectric photometry of Polaris starting in early 2002. This photometry is a continuation of the work done on Polaris by Kamper and Fernie. Our observations were made to obtain new epochal light curves and accurate times of maximum light. We secured well defined 450 nm and 550 nm light curves from which we extracted accurate measures of light amplitudes of 0.033 +/- 0.004 mag and 0.028 +/- 0.003 mag, respectively. These light amplitudes are slightly larger than those observed during the early 1990s. So it appears that the century long decrease in the light amplitude has halted (or paused). Our time of maximum light was combined with previous timings and reaffirms the increase in period of +3.2 sec/yr. These observations lend strong support to overtone nature of Polaris's pulsations, whose transition from moderate to low amplitude pulsator will be discussed in more detail in this poster. In addition to the long-term secular increase in the Polaris's pulsation period, an analysis of the O-Cs indicates +/-0.25 day cyclic oscillations in the apparent period with time scale of 11-12 years. The nature of these period oscillations is being investigated and will be discussed. We gratefully acknowledge the support for this research from NSF/RUI Grant AST 00

  4. Wi-Fi Versus Cell Phone Service

    Science.gov (United States)

    Roberts, Gary

    2006-01-01

    Regardless of whether cell phones remain the dominant platform or Wi-Fi becomes the prevalent platform, there are some things that libraries can do to improve patron service in light of evolving expectations, behaviors, and tools. People today are more nomadic, which leads to the very real possibility of having to deliver content not just to the…

  5. SeaWiFS technical report series. Volume 11: Analysis of selected orbit propagation models for the SeaWiFS mission

    Science.gov (United States)

    Patt, Frederick S.; Hoisington, Charles M.; Gregg, Watson W.; Coronado, Patrick L.; Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor); Indest, A. W. (Editor)

    1993-01-01

    An analysis of orbit propagation models was performed by the Mission Operations element of the Sea-viewing Wide Field-of-View Sensor (SeaWiFS) Project, which has overall responsibility for the instrument scheduling. The orbit propagators selected for this analysis are widely available general perturbations models. The analysis includes both absolute accuracy determination and comparisons of different versions of the models. The results show that all of the models tested meet accuracy requirements for scheduling and data acquisition purposes. For internal Project use the SGP4 propagator, developed by the North American Air Defense (NORAD) Command, has been selected. This model includes atmospheric drag effects and, therefore, provides better accuracy. For High Resolution Picture Transmission (HRPT) ground stations, which have less stringent accuracy requirements, the publicly available Brouwer-Lyddane models are recommended. The SeaWiFS Project will make available portable source code for a version of this model developed by the Data Capture Facility (DCF).

  6. Partial pressure (or fugacity) of carbon dioxide, salinity and other variables collected from underway - surface observations using Carbon dioxide (CO2) gas analyzer, Shower head chamber equilibrator for autonomous carbon dioxide (CO2) measurement and other instruments from the USCGC POLAR STAR in the Coral Sea, North Pacific Ocean and others from 2001-11-02 to 2002-04-23 (NODC Accession 0108234)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0108234 includes chemical, meteorological, physical and underway - surface data collected from USCGC POLAR STAR in the Coral Sea, North Pacific Ocean,...

  7. SeaWiFS Third Anniversary Global Biosphere

    Science.gov (United States)

    2002-01-01

    September 18,2000 is the third anniversary of the start of regular SeaWiFS operations of this remarkable planet called Earth. This SeaWiFS image is of the Global Biosphere depicting the ocean's long-term average phytoplankton chlorophyll concentration acquired between September 1997 and August 2000 combined with the SeaWiFS-derived Normalized Difference Vegetation Index (NDVI) over land during July 2000.

  8. The WiLI benchmark dataset for written language identification

    OpenAIRE

    Thoma, Martin

    2018-01-01

    This paper describes the WiLI-2018 benchmark dataset for monolingual written natural language identification. WiLI-2018 is a publicly available, free of charge dataset of short text extracts from Wikipedia. It contains 1000 paragraphs of 235 languages, totaling in 23500 paragraphs. WiLI is a classification dataset: Given an unknown paragraph written in one dominant language, it has to be decided which language it is.

  9. Mapping of MAC Address with Moving WiFi Scanner

    Directory of Open Access Journals (Sweden)

    Arief Hidayat

    2017-10-01

    Full Text Available Recently, Wifi is one of the most useful technologies that can be used for detecting and counting MAC Address. This paper described using of WiFi scanner which carried out seven times circulated the bus. The method used WiFi and GPS are to counting MAC address as raw data from the pedestrian smartphone, bus passenger or WiFi devices near from the bus as long as the bus going around the route. There are seven processes to make map WiFi data.

  10. Sharing your urban residential WiFi (UR-WiFi)

    NARCIS (Netherlands)

    Kawade, Santosh; van Bloem, J.W.H.; Abhayawardhana, V.S.; Wisely, D.

    2006-01-01

    Cheap and ubiquitous broadband wireless access is what most of the operators are aiming for. This paper analyses an innovative proposal to extend the traditional fixed coverage offered by residential broadband into an urban wireless coverage using urban residential wireless fidelity (UR-WiFi)

  11. WiFi networks and malware epidemiology.

    Science.gov (United States)

    Hu, Hao; Myers, Steven; Colizza, Vittoria; Vespignani, Alessandro

    2009-02-03

    In densely populated urban areas WiFi routers form a tightly interconnected proximity network that can be exploited as a substrate for the spreading of malware able to launch massive fraudulent attacks. In this article, we consider several scenarios for the deployment of malware that spreads over the wireless channel of major urban areas in the US. We develop an epidemiological model that takes into consideration prevalent security flaws on these routers. The spread of such a contagion is simulated on real-world data for georeferenced wireless routers. We uncover a major weakness of WiFi networks in that most of the simulated scenarios show tens of thousands of routers infected in as little as 2 weeks, with the majority of the infections occurring in the first 24-48 h. We indicate possible containment and prevention measures and provide computational estimates for the rate of encrypted routers that would stop the spreading of the epidemics by placing the system below the percolation threshold.

  12. Wi-Fi Service enhancement at CERN

    Science.gov (United States)

    Ducret, V.; Sosnowski, A.; Gonzalez Caballero, B.; Barrand, Q.

    2017-10-01

    Since the early 2000’s, the number of mobile devices connected to CERN’s internal network has increased from just a handful to well over 10,000. Wireless access is no longer simply “nice to have” or just for conference and meeting rooms; support for mobility is expected by most, if not all, of the CERN community. In this context, a full renewal of the CERN Wi-Fi network has been launched to deliver a state-of-the-art campus-wide Wi-Fi Infrastructure. We aim to deliver, in more than 200 office buildings with a surface area of over 400,000m2 and including many high-priority and high-occupation zones, an end-user experience comparable, for most applications, to a wired connection and with seamless mobility support. We describe here the studies and tests performed at CERN to ensure the solution we are deploying can meet these goals as well as delivering a single, simple, flexible and open management platform.

  13. WiFi networks and malware epidemiology

    Science.gov (United States)

    Hu, Hao; Myers, Steven; Colizza, Vittoria; Vespignani, Alessandro

    2009-01-01

    In densely populated urban areas WiFi routers form a tightly interconnected proximity network that can be exploited as a substrate for the spreading of malware able to launch massive fraudulent attacks. In this article, we consider several scenarios for the deployment of malware that spreads over the wireless channel of major urban areas in the US. We develop an epidemiological model that takes into consideration prevalent security flaws on these routers. The spread of such a contagion is simulated on real-world data for georeferenced wireless routers. We uncover a major weakness of WiFi networks in that most of the simulated scenarios show tens of thousands of routers infected in as little as 2 weeks, with the majority of the infections occurring in the first 24–48 h. We indicate possible containment and prevention measures and provide computational estimates for the rate of encrypted routers that would stop the spreading of the epidemics by placing the system below the percolation threshold. PMID:19171909

  14. Eduroam: Secure WiFi roaming for education and research

    CSIR Research Space (South Africa)

    Miteff, S

    2012-10-01

    Full Text Available ? No security ? ?Hotel WiFi? - captive portal ? WPA2-Personal ? Don't permit guest access Pillars of information security ? Confidentiality ? Integrity ? Availability ? Did you just DoS yourself? ? We need a better plan The better plan: WiFi roaming...

  15. Wireless Fidelity (Wi-Fi) Broadband Network Technology: An ...

    African Journals Online (AJOL)

    Wireless Fidelity (Wi-Fi) broadband network technology has made tremendous impact in the growth of broadband wireless networks. There exists today several Wi-Fi access points that allow employees, partners and customers to access corporate data from almost anywhere and anytime. Wireless broadband networks are ...

  16. 75 FR 30300 - Drawbridge Operation Regulations; Root River, Racine, WI

    Science.gov (United States)

    2010-06-01

    ... DEPARTMENT OF HOMELAND SECURITY Coast Guard 33 CFR Part 117 [Docket No. USCG-2010-0414] Drawbridge Operation Regulations; Root River, Racine, WI AGENCY: Coast Guard, DHS. ACTION: Notice of temporary... Bridge at Mile 0.53 over the Root River, at Racine, WI. This deviation will temporarily change the...

  17. Wi-Fi Coexistence with Duty Cycled LTE-U

    Directory of Open Access Journals (Sweden)

    Yimin Pang

    2017-01-01

    Full Text Available Coexistence of Wi-Fi and LTE-Unlicensed (LTE-U technologies has drawn significant concern in industry. In this paper, we investigate the Wi-Fi performance in the presence of duty cycle based LTE-U transmission on the same channel. More specifically, one LTE-U cell and one Wi-Fi basic service set (BSS coexist by allowing LTE-U devices to transmit their signals only in predetermined duty cycles. Wi-Fi stations, on the other hand, simply contend the shared channel using the distributed coordination function (DCF protocol without cooperation with the LTE-U system or prior knowledge about the duty cycle period or duty cycle of LTE-U transmission. We define the fairness of the above scheme as the difference between Wi-Fi performance loss ratio (considering a defined reference performance and the LTE-U duty cycle (or function of LTE-U duty cycle. Depending on the interference to noise ratio (INR being above or below −62 dbm, we classify the LTE-U interference as strong or weak and establish mathematical models accordingly. The average throughput and average service time of Wi-Fi are both formulated as functions of Wi-Fi and LTE-U system parameters using probability theory. Lastly, we use the Monte Carlo analysis to demonstrate the fairness of Wi-Fi and LTE-U air time sharing.

  18. Tracking Human Mobility Using WiFi Signals

    DEFF Research Database (Denmark)

    Sapiezynski, Piotr; Stopczynski, Arkadiusz; Gatej, Radu

    2015-01-01

    We study six months of human mobility data, including WiFi and GPS traces recorded with high temporal resolution, and find that time series of WiFi scans contain a strong latent location signal. In fact, due to inherent stability and low entropy of human mobility, it is possible to assign location...... to WiFi access points based on a very small number of GPS samples and then use these access points as location beacons. Using just one GPS observation per day per person allows us to estimate the location of, and subsequently use, WiFi access points to account for 80% of mobility across a population....... These results reveal a great opportunity for using ubiquitous WiFi routers for high-resolution outdoor positioning, but also significant privacy implications of such side-channel location tracking....

  19. Challenges for Social Sensing using WiFi Signals

    DEFF Research Database (Denmark)

    Kjærgaard, Mikkel Baun; Nurmi, Petteri

    2012-01-01

    Smartphones are an attractive option for social sensing due to their widespread market penetration rate and advanced sensing capabilities. Enabling social sensing on smartphones would require techniques that can accurately detect and characterize physical proximity, an important prerequisite...... for the capture of more complex social phenomena. One of the most promising modalities for this purpose is WiFi, as it works both indoors and outdoors, and as WiFi signal environment tends to contain significant spatial variation. A challenge in using WiFi, however, is that the signals are affected by many noise...... sources, such as fast fading, body attenuation, hardware differences and varying access points densities. In this paper we review existing work on using WiFi for social sensing and outline challenges that have to be addressed to utilize WiFi at large for social sensing....

  20. Tracking Human Mobility Using WiFi Signals.

    Science.gov (United States)

    Sapiezynski, Piotr; Stopczynski, Arkadiusz; Gatej, Radu; Lehmann, Sune

    2015-01-01

    We study six months of human mobility data, including WiFi and GPS traces recorded with high temporal resolution, and find that time series of WiFi scans contain a strong latent location signal. In fact, due to inherent stability and low entropy of human mobility, it is possible to assign location to WiFi access points based on a very small number of GPS samples and then use these access points as location beacons. Using just one GPS observation per day per person allows us to estimate the location of, and subsequently use, WiFi access points to account for 80% of mobility across a population. These results reveal a great opportunity for using ubiquitous WiFi routers for high-resolution outdoor positioning, but also significant privacy implications of such side-channel location tracking.

  1. Field Study of all GSM and WiFi Networks in Amman City from Geospatial Perspective

    Science.gov (United States)

    Hawarey, Mosab; Alibrahim, Mustafa; Jetto, Hamza; Salah Mahmoud, Firas

    2016-04-01

    A thorough field study over multiple months has been conducted in the streets of Amman, the capital city of Jordan, in order to collect massive amounts of GSM and WiFi data and analyze them from geospatial perspective. Some interesting realities have been detected; e.g. the North and West of Amman are much better served by GSM operators than the East, South, and Center. Also, the security measures taken to protect WiFi networks in the North and West are much better than those in the East, South, and Center. This has led to the recognition of an interesting pattern that groups the North and West together, while the East, South, and Center constitute another group. Extremely interesting finding was found; the GSM signals are so strong at certain locations that they constitute direct lethal threat to human health; it is scientifically documented that such strengths would lead to certain human cell mutations and cancer. The exact locations and contributors of such hazards will be disclosed in this paper for the first time. Many tabular and graphical presentations of the data will be presented.

  2. Holography of Wi-fi Radiation

    Science.gov (United States)

    Holl, Philipp M.; Reinhard, Friedemann

    2017-05-01

    Wireless data transmission systems such as wi-fi or Bluetooth emit coherent light—electromagnetic waves with a precisely known amplitude and phase. Propagating in space, this radiation forms a hologram—a two-dimensional wave front encoding a three-dimensional view of all objects traversed by the light beam. Here we demonstrate a scheme to record this hologram in a phase-coherent fashion across a meter-sized imaging region. We recover three-dimensional views of objects and emitters by feeding the resulting data into digital reconstruction algorithms. Employing a digital implementation of dark-field propagation to suppress multipath reflection, we significantly enhance the quality of the resulting images. We numerically simulate the hologram of a 10-m-sized building, finding that both localization of emitters and 3D tomography of absorptive objects could be feasible by this technique.

  3. Tracking Human Mobility Using WiFi Signals

    DEFF Research Database (Denmark)

    Sapiezynski, Piotr; Stopczynski, Arkadiusz; Gatej, Radu

    2015-01-01

    We study six months of human mobility data, including WiFi and GPS traces recorded with high temporal resolution, and find that time series of WiFi scans contain a strong latent location signal. In fact, due to inherent stability and low entropy of human mobility, it is possible to assign locatio....... These results reveal a great opportunity for using ubiquitous WiFi routers for high-resolution outdoor positioning, but also significant privacy implications of such side-channel location tracking.......We study six months of human mobility data, including WiFi and GPS traces recorded with high temporal resolution, and find that time series of WiFi scans contain a strong latent location signal. In fact, due to inherent stability and low entropy of human mobility, it is possible to assign location...... to WiFi access points based on a very small number of GPS samples and then use these access points as location beacons. Using just one GPS observation per day per person allows us to estimate the location of, and subsequently use, WiFi access points to account for 80% of mobility across a population...

  4. Community Based Networks and 5G Wi-Fi

    DEFF Research Database (Denmark)

    Williams, Idongesit

    2018-01-01

    This paper argues on why Community Based Networks should be recognized as potential 5G providers using 5G Wi-Fi. The argument is hinged on findings in a research to understand why Community Based Networks deploy telecom and Broadband infrastructure. The study was a qualitative study carried out...... inductively using Grounded Theory. Six cases were investigated. Two Community Based Network Mobilization Models were identified. The findings indicate that 5G Wi-Fi deployment by Community Based Networks is possible if policy initiatives and the 5G Wi-Fi standards are developed to facilitate the causal...

  5. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Brorsen, Michael; Frigaard, Peter

    Denne rapport beskriver numeriske beregninger af forskellige flydergeometrier for bølgeenergianlæget Wave Star.......Denne rapport beskriver numeriske beregninger af forskellige flydergeometrier for bølgeenergianlæget Wave Star....

  6. 76 FR 35831 - Television Broadcasting Services; Eau Claire, WI

    Science.gov (United States)

    2011-06-20

    ...] Television Broadcasting Services; Eau Claire, WI AGENCY: Federal Communications Commission. ACTION: Proposed rule. SUMMARY: The Commission has before it a petition for rulemaking filed by Gray Television Licensee... 73 Television, Television broadcasting. Federal Communications Commission. Barbara A. Kreisman, Chief...

  7. Molecular Star

    Indian Academy of Sciences (India)

    This report describes the making of a self-assembled coordination architecture that is named as a 'molecular star' since it resembles the shape of a star; more specifically a five-pointed star. This work has been already published in Chemistry- A European Jour- nal in the September 2017 issue and was featured in the cover.

  8. Novel Approaches to Enhance Mobile WiMAX Security

    Directory of Open Access Journals (Sweden)

    Taeshik Shon

    2010-01-01

    Full Text Available The IEEE 802.16 Working Group on Broadband Wireless Access Standards released IEEE 802.16-2004 which is a standardized technology for supporting broadband and wireless communication with fixed and nomadic access. After the IEEE 802.16-2004 standard, a new advanced and revised standard was released as the IEEE 802.16e-2005 amendment which is foundation of Mobile WiMAX network supporting handover and roaming capabilities. In the area of security aspects, compared to IEEE 802.16-2004, IEEE 802.16e, called Mobile WiMAX, adopts improved security architecture—PKMv2 which includes EAP authentication, AES-based authenticated encryption, and CMAC or HMAC message protection. However, there is no guarantee that PKMv2-based Mobile WiMAX network will not have security flaws. In this paper, we investigate the current Mobile WiMAX security architecture focusing mainly on pointing out new security vulnerabilities such as a disclosure of security context in network entry, a lack of secure communication in network domain, and a necessity of efficient handover supporting mutual authentication. Based on the investigation results, we propose a novel Mobile WiMAX security architecture, called RObust and Secure MobilE WiMAX (ROSMEX, to prevent the new security vulnerabilities.

  9. The Audacity of Fiber-Wireless (FiWi) Networks

    Science.gov (United States)

    Maier, Martin; Ghazisaidi, Navid; Reisslein, Martin

    A plethora of enabling optical and wireless technologies have been emerging that can be used to build future-proof bimodal fiber-wireless (FiWi) broadband access networks. After overviewing key enabling radio-over-fiber (RoF) and radio-and-fiber (R&F) technologies and briefly surveying the state of the art of FiWi networks, we introduce an Ethernet-based access-metro FiWi network, called SuperMAN, that integrates next-generation WiFi and WiMAX networks with WDM-enhanced EPON and RPR networks. Throughout the paper we pay close attention to the technical challenges and opportunities of FiWi networks, but also elaborate on their societal benefits and potential to shift the current research focus from optical-wireless networking to the exploitation of personal and in-home computing facilities to create new unforeseen services and applications as we are about to enter the Petabyte age.

  10. Wi-Fi/MARG Integration for Indoor Pedestrian Localization.

    Science.gov (United States)

    Tian, Zengshan; Jin, Yue; Zhou, Mu; Wu, Zipeng; Li, Ze

    2016-12-10

    With the wide deployment of Wi-Fi networks, Wi-Fi based indoor localization systems that are deployed without any special hardware have caught significant attention and have become a currently practical technology. At the same time, the Magnetic, Angular Rate, and Gravity (MARG) sensors installed in commercial mobile devices can achieve highly-accurate localization in short time. Based on this, we design a novel indoor localization system by using built-in MARG sensors and a Wi-Fi module. The innovative contributions of this paper include the enhanced Pedestrian Dead Reckoning (PDR) and Wi-Fi localization approaches, and an Extended Kalman Particle Filter (EKPF) based fusion algorithm. A new Wi-Fi/MARG indoor localization system, including an Android based mobile client, a Web page for remote control, and a location server, is developed for real-time indoor pedestrian localization. The extensive experimental results show that the proposed system is featured with better localization performance, with the average error 0.85 m, than the one achieved by using the Wi-Fi module or MARG sensors solely.

  11. Wi-Fi/MARG Integration for Indoor Pedestrian Localization

    Directory of Open Access Journals (Sweden)

    Zengshan Tian

    2016-12-01

    Full Text Available With the wide deployment of Wi-Fi networks, Wi-Fi based indoor localization systems that are deployed without any special hardware have caught significant attention and have become a currently practical technology. At the same time, the Magnetic, Angular Rate, and Gravity (MARG sensors installed in commercial mobile devices can achieve highly-accurate localization in short time. Based on this, we design a novel indoor localization system by using built-in MARG sensors and a Wi-Fi module. The innovative contributions of this paper include the enhanced Pedestrian Dead Reckoning (PDR and Wi-Fi localization approaches, and an Extended Kalman Particle Filter (EKPF based fusion algorithm. A new Wi-Fi/MARG indoor localization system, including an Android based mobile client, a Web page for remote control, and a location server, is developed for real-time indoor pedestrian localization. The extensive experimental results show that the proposed system is featured with better localization performance, with the average error 0.85 m, than the one achieved by using the Wi-Fi module or MARG sensors solely.

  12. The WAGGS project - I. The WiFeS Atlas of Galactic Globular cluster Spectra

    Science.gov (United States)

    Usher, Christopher; Pastorello, Nicola; Bellstedt, Sabine; Alabi, Adebusola; Cerulo, Pierluigi; Chevalier, Leonie; Fraser-McKelvie, Amelia; Penny, Samantha; Foster, Caroline; McDermid, Richard M.; Schiavon, Ricardo P.; Villaume, Alexa

    2017-07-01

    We present the WiFeS Atlas of Galactic Globular cluster Spectra, a library of integrated spectra of Milky Way and Local Group globular clusters. We used the WiFeS integral field spectrograph on the Australian National University 2.3 m telescope to observe the central regions of 64 Milky Way globular clusters and 22 globular clusters hosted by the Milky Way's low-mass satellite galaxies. The spectra have wider wavelength coverage (3300-9050 Å) and higher spectral resolution (R = 6800) than existing spectral libraries of Milky Way globular clusters. By including Large and Small Magellanic Cloud star clusters, we extend the coverage of parameter space of existing libraries towards young and intermediate ages. While testing stellar population synthesis models and analysis techniques is the main aim of this library, the observations may also further our understanding of the stellar populations of Local Group globular clusters and make possible the direct comparison of extragalactic globular cluster integrated light observations with well-understood globular clusters in the Milky Way. The integrated spectra are publicly available via the project website.

  13. SeaShark and Starfish opertional data processing schemes for AVHRR and SeaWiFs

    Science.gov (United States)

    Flowerdew, R. J.; Corlyon, Anaa M.; Greer, W. A. D.; Newby, Steve J.; Winder, C. P.

    1997-02-01

    SeaShark is an operational software package for processing, archiving and cataloguing AVHRR and SeaWiFS data using an operator friendly GUI. Upon receipt of a customer order, it produces standard AVHRR data products, including Sea Surface Temperature (SST) and it has recently been modified to include SeaWiFS level 2 data processing. This uses an atmospheric correction scheme developed by the Plymouth Marine Laboratory, UK (PML) that builds upon the standard Gordon and Wang approach to be applicable over both case 1 and case 2 waters. Higher level products are then generated using PML algorithms, including chlorophyll a, a CZCS-type pigment, Kd, and suspended particulate matter. Outputs are in CEOS-compatible format. The software also produces fast delivery products (FDPs) of chlorophyll a and SST. These FDPs are combined in the StarFish software package to provide maps indicating potential location of phytoplankton and the preferred thermal environment of certain pelagic fish species. Fishing vessels may obtain these maps over Inmarsat, allowing them to achieve a greater efficiency hence lower cost.

  14. Shallow-water brittle-star (Echinodermata: Ophiuroidea) assemblages from the Aptian (Early Cretaceous) of the North Atlantic:first insights into bathymetric distribution patterns

    OpenAIRE

    Thuy, Ben; Gale, Andrew S.; Stöhr, Sabine; Wiese, Frank

    2014-01-01

    In spite of their excellent preservation potential and abundance, brittle-star microfossils are still an underexploited source of alpha-taxonomical data. Knowledge on the Lower Cretaceous fossil record of the ophiuroids is particularly patchy, hampering the use of the ophiuroids as a model organism to explore macroevolutionary, taphonomic and other further-reaching aspects. Here, we describe three ophiuroid assemblages mostly based on dissociated lateral arm plates from the early Aptian of Cu...

  15. Wi-Fi is an important threat to human health.

    Science.gov (United States)

    Pall, Martin L

    2018-03-21

    Repeated Wi-Fi studies show that Wi-Fi causes oxidative stress, sperm/testicular damage, neuropsychiatric effects including EEG changes, apoptosis, cellular DNA damage, endocrine changes, and calcium overload. Each of these effects are also caused by exposures to other microwave frequency EMFs, with each such effect being documented in from 10 to 16 reviews. Therefore, each of these seven EMF effects are established effects of Wi-Fi and of other microwave frequency EMFs. Each of these seven is also produced by downstream effects of the main action of such EMFs, voltage-gated calcium channel (VGCC) activation. While VGCC activation via EMF interaction with the VGCC voltage sensor seems to be the predominant mechanism of action of EMFs, other mechanisms appear to have minor roles. Minor roles include activation of other voltage-gated ion channels, calcium cyclotron resonance and the geomagnetic magnetoreception mechanism. Five properties of non-thermal EMF effects are discussed. These are that pulsed EMFs are, in most cases, more active than are non-pulsed EMFs; artificial EMFs are polarized and such polarized EMFs are much more active than non-polarized EMFs; dose-response curves are non-linear and non-monotone; EMF effects are often cumulative; and EMFs may impact young people more than adults. These general findings and data presented earlier on Wi-Fi effects were used to assess the Foster and Moulder (F&M) review of Wi-Fi. The F&M study claimed that there were seven important studies of Wi-Fi that each showed no effect. However, none of these were Wi-Fi studies, with each differing from genuine Wi-Fi in three distinct ways. F&M could, at most conclude that there was no statistically significant evidence of an effect. The tiny numbers studied in each of these seven F&M-linked studies show that each of them lack power to make any substantive conclusions. In conclusion, there are seven repeatedly found Wi-Fi effects which have also been shown to be caused by other

  16. Star Wreck

    CERN Document Server

    Kusenko, A; Tinyakov, Peter G; Tkachev, Igor I; Kusenko, Alexander; Shaposhnikov, Mikhail; Tkachev, Igor I.

    1998-01-01

    Electroweak models with low-energy supersymmetry breaking predict the existence of stable non-topological solitons, Q-balls, that can be produced in the early universe. The relic Q-balls can accumulate inside a neutron star and gradually absorb the baryons into the scalar condensate. This causes a slow reduction in the mass of the star. When the mass reaches a critical value, the neutron star becomes unstable and explodes. The cataclysmic destruction of the distant neutron stars may be the origin of the gamma-ray bursts.

  17. A campus-wide Wi-Fi service for CERN

    CERN Document Server

    2016-01-01

    Improvements are coming to CERN’s Wi-Fi service as connectivity is improved in offices, restaurants and meeting rooms.   All Wi-Fi traffic will be routed via central controllers in CERN’s Computer Centre to provide a better managed service. (Image: Veronika McQuade/CERN) The IT department’s Communication Systems group has provided Wi-Fi connectivity at CERN for many years now but with a focus on meeting rooms, auditoriums and informal meeting places such as the restaurants. Although some buildings have Wi-Fi coverage in offices, most do not and CERN’s Wi-Fi service is lagging behind the demand driven by the growing number of tablets, lightweight laptops and other wireless-only devices. Furthermore, the current network infrastructure can’t cope with the many devices in the Main Auditorium during events such as the recent LIGO announcement and it often has difficulty handling the demand at Restaurant 1 during lunchtimes. The wireless access points d...

  18. Energy consumption model on WiMAX subscriber station

    Science.gov (United States)

    Mubarakah, N.; Suherman; Al-Hakim, M. Y.; Warman, E.

    2018-02-01

    Mobile communication technologies move toward miniaturization. Mobile device’s energy source relies on its battery endurance. The smaller the mobile device, it is expected the slower the battery drains. Energy consumption reduction in mobile devices has been of interest of researcher. In order to optimize energy consumption, its usage should be predictable. This paper proposes a model of predicted energy amount consumed by the WiMAX subscriber station by using regression analysis of active WiMAX states and their durations. The proposed model was assessed by using NS-2 simulation for more than a hundred thousand of recorded energy consumptions data in every WiMAX states. The assessment show a small average deviation between predicted and measured energy consumptions, about 0.18% for training data and 0.187% and 0.191% for test data.

  19. Star Polymers.

    Science.gov (United States)

    Ren, Jing M; McKenzie, Thomas G; Fu, Qiang; Wong, Edgar H H; Xu, Jiangtao; An, Zesheng; Shanmugam, Sivaprakash; Davis, Thomas P; Boyer, Cyrille; Qiao, Greg G

    2016-06-22

    Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

  20. Star Imager

    DEFF Research Database (Denmark)

    Madsen, Peter Buch; Jørgensen, John Leif; Thuesen, Gøsta

    1997-01-01

    The version of the star imager developed for Astrid II is described. All functions and features are described as well as the operations and the software protocol.......The version of the star imager developed for Astrid II is described. All functions and features are described as well as the operations and the software protocol....

  1. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Brorsen, Michael; Frigaard, Peter

    Nærværende rapport beskriver numeriske beregninger af den hydrodynamiske interaktion mellem 5 flydere i bølgeenergianlægget Wave Star.......Nærværende rapport beskriver numeriske beregninger af den hydrodynamiske interaktion mellem 5 flydere i bølgeenergianlægget Wave Star....

  2. DNA synthesis in permeabilized WI38 and MRC5 cells

    International Nuclear Information System (INIS)

    Griffiths, T.D.; Carpenter, J.G.

    1980-01-01

    DNA synthesis was examined in cultures of growing WI38 and MRC5 cells made permeable to deoxyribonucleotides. Cells from late passage cultures showed a reduced rate of deoxythymidine triphosphate (dTTP) uptake as compared to cells from early- to mid-passage cultures. This reduction became evident earlier in WI38 cultures (passage 33) than in MRC5 cultures (passage 41). Although this reduced rate of incorporation appeared to be primarily due to a reduced percentage of replicating (S phase) cells in later passage cultures, some effect on the rate of DNA synthesis in replicating cells was also evident

  3. Maritime super Wi-Fi coverage based on TVWS

    Science.gov (United States)

    Ren, Jia; Chen, Baodan; Zhang, Yonghui; Huang, Fang

    2014-10-01

    After analyzing the occupancy and characteristics of television white space (TVWS), this paper proposes wireless broadband networking by using super Wi-Fi technology in maritime environment operating on TVWS. A sea surface channel model is developed for predicting maritime network coverage of super Wi-Fi technology. This channel model is based on Irregular Terrain Methodology (ITM) model with revised parameters and dual-path propagation effect. The simulations demonstrated that the sea surface channel model can accurately reflect the transmission loss of radio wave in TVWS.

  4. ANDROID CHATTING APPLICATION BASED ON WI-FI TECHNOLOGY

    OpenAIRE

    Ekata M. Lambture *, Prof. Z.M. Shaikh

    2016-01-01

    As we know that Android operating system is one of the popular operating system for mobile applications.It supports mobile applications such as Chatting based applications,File sharing applications etc. In market thosands of applications are available in which users can send-receive messages,shares the files,send images,audio,video through network connectivity such as 2G,3G,4G. Android chatting application based on wi-fi technology provides same features but using WI-FI(Wireless Fidelity)...

  5. Eesti Statoil seljatas emaettevõtte WiFiga / Annika Matson

    Index Scriptorium Estoniae

    Matson, Annika, 1976-

    2003-01-01

    Eesti teenindusjaamades pakutakse alates suvest tasuta traadita internetiühendust WiFi, Skandinaavimaades on WiFi alles paigutamisel. Lõpuks kasumis: tabelid ja diagrammid. Vt. samas: Statoili arengut pärsib maardlate ammendumine

  6. Primary Productivity, SeaWiFS and Pathfinder, 0.1 degrees, Global, EXPERIMENTAL

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Primary Productivity is calculated from SeaWiFS Chl a, Pathfinder SST, and SeaWiFS PAR data. THIS IS AN EXPERIMENTAL PRODUCT: intended strictly for scientific...

  7. Dark stars

    DEFF Research Database (Denmark)

    Maselli, Andrea; Pnigouras, Pantelis; Nielsen, Niklas Grønlund

    2017-01-01

    to the formation of compact objects predominantly made of dark matter. Considering both fermionic and bosonic (scalar φ4) equations of state, we construct the equilibrium structure of rotating dark stars, focusing on their bulk properties and comparing them with baryonic neutron stars. We also show that these dark...... objects admit the I-Love-Q universal relations, which link their moments of inertia, tidal deformabilities, and quadrupole moments. Finally, we prove that stars built with a dark matter equation of state are not compact enough to mimic black holes in general relativity, thus making them distinguishable...

  8. Estimating travel times using Wi-Fi sensor data

    NARCIS (Netherlands)

    Hoogendoorn, S.P.; Daamen, W.; Duives, D.C.; Yuan, Y.

    2016-01-01

    Determining travel time information from Wi-Fi (or Bluetooth) sensors is not trivial due to various (often technical) reasons. In this contribution, we focus on the problem of distinguishing travel time from the time people spend performing activities (e.g. fuelling the car, standing still to watch

  9. Wi-Fi Network Communication Technology Design | Onibere ...

    African Journals Online (AJOL)

    Transmission media (like Satellite, VSAT), access method used to transmit both voice and data on the networks and underlying software and hardware requirements. Also the various standards and protocol for proper wireless networks management, the various authentication and encryption techniques of Wi -Fi network ...

  10. 76 FR 49697 - Television Broadcasting Services; Eau Claire, WI

    Science.gov (United States)

    2011-08-11

    ...] Television Broadcasting Services; Eau Claire, WI AGENCY: Federal Communications Commission. ACTION: Final rule. SUMMARY: The Commission has before it a petition for rulemaking filed by Gray Television Licensee... the Congressional review Act, see 5 U.S.C. 801(a)(1)(A). List of Subjects in 47 CFR Part 73 Television...

  11. 76 FR 68124 - Television Broadcasting Services; Fond du Lac, WI

    Science.gov (United States)

    2011-11-03

    ... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 [MB Docket No. 09-115, RM-11543; DA 11-1502] Television Broadcasting Services; Fond du Lac, WI AGENCY: Federal Communications Commission. ACTION: Proposed rule. SUMMARY: In this document, the Commission denies a petition for reconsideration of an August 12...

  12. 76 FR 5300 - Proposed Amendment of Class E Airspace; Cable Union, WI

    Science.gov (United States)

    2011-01-31

    ... Federal Aviation Administration 14 CFR Part 71 Proposed Amendment of Class E Airspace; Cable Union, WI...: This action proposes to amend Class E airspace at Cable Union, WI. Decommissioning of the Seely non-directional beacon (NDB) at Cable Union Airport, Cable Union, WI, has made this action necessary for the...

  13. 76 FR 22014 - Amendment of Class E Airspace; Cable Union, WI

    Science.gov (United States)

    2011-04-20

    ... Federal Aviation Administration 14 CFR Part 71 Amendment of Class E Airspace; Cable Union, WI AGENCY... airspace for Cable Union, WI. Decommissioning of the Seely non-directional beacon (NDB) at Cable Union Airport, Cable Union, WI, has made this action necessary to enhance the safety and management of...

  14. The role of regulation in preventing Wi-Fi over-congestion in densely populated areas

    NARCIS (Netherlands)

    Hartog, F.T.H. den; Nijs, J.M.M. de

    2017-01-01

    Given the ever increasing number of Wi-Fi devices in use by the public, the progressing urbanisation, and the current attempts by the industry to improve Wi-Fi system performance, we here analyse the case of apartment blocks with residents increasingly suffering from Wi-Fi over-congestion. Here,

  15. Star formation

    International Nuclear Information System (INIS)

    Woodward, P.R.

    1978-01-01

    Theoretical models of star formation are discussed beginning with the earliest stages and ending in the formation of rotating, self-gravitating disks or rings. First a model of the implosion of very diffuse gas clouds is presented which relies upon a shock at the edge of a galactic spiral arm to drive the implosion. Second, models are presented for the formation of a second generation of massive stars in such a cloud once a first generation has formed. These models rely on the ionizing radiation from massive stars or on the supernova shocks produced when these stars explode. Finally, calculations of the gravitational collapse of rotating clouds are discussed with special focus on the question of whether rotating disks or rings are the result of such a collapse. 65 references

  16. Carbon Stars

    Indian Academy of Sciences (India)

    Abstract. In this paper, the present state of knowledge of the carbon stars is discussed. Particular attention is given to issues of classification, evolution, variability, populations in our own and other galaxies, and circumstellar material.

  17. Star formation

    Energy Technology Data Exchange (ETDEWEB)

    Woodward, P.R.

    1978-09-27

    Theoretical models of star formation are discussed beginning with the earliest stages and ending in the formation of rotating, self-gravitating disks or rings. First a model of the implosion of very diffuse gas clouds is presented which relies upon a shock at the edge of a galactic spiral arm to drive the implosion. Second, models are presented for the formation of a second generation of massive stars in such a cloud once a first generation has formed. These models rely on the ionizing radiation from massive stars or on the supernova shocks produced when these stars explode. Finally, calculations of the gravitational collapse of rotating clouds are discussed with special focus on the question of whether rotating disks or rings are the result of such a collapse. 65 references.

  18. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Frigaard, Peter

    Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Byggeri og Anlæg med bølgeenergianlæget Wave Star.......Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Byggeri og Anlæg med bølgeenergianlæget Wave Star....

  19. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Andersen, Thomas Lykke

    Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star.......Nærværende rapport beskriver modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star....

  20. WiFi-Aided Magnetic Matching for Indoor Navigation with Consumer Portable Devices

    Directory of Open Access Journals (Sweden)

    You Li

    2015-06-01

    Full Text Available This paper presents a WiFi-aided magnetic matching (MM algorithm for indoor pedestrian navigation with consumer portable devices. This algorithm reduces both the mismatching rate (i.e., the rate of matching to an incorrect point that is more than 20 m away from the true value and computational load of MM by using WiFi positioning solutions to limit the MM search space. Walking tests with Samsung Galaxy S3 and S4 smartphones in two different indoor environments (i.e., Environment #1 with abundant WiFi APs and significant magnetic features, and Environment #2 with less WiFi and magnetic information were conducted to evaluate the proposed algorithm. It was found that WiFi fingerprinting accuracy is related to the signal distributions. MM provided results with small fluctuations but had a significant mismatch rate; when aided by WiFi, MM’s robustness was significantly improved. The outcome of this research indicates that WiFi and MM have complementary characteristics as the former is a point-by-point matching approach and the latter is based on profile-matching. Furthermore, performance improvement through integrating WiFi and MM depends on the environment (e.g., the signal distributions of magnetic intensity and WiFi RSS: In Environment #1 tests, WiFi-aided MM and WiFi provided similar results; in Environment #2 tests, the former was approximately 41.6% better. Our results supported that the WiFi-aided MM algorithm provided more reliable solutions than both WiFi and MM in the areas that have poor WiFi signal distribution or indistinctive magnetic-gradient features.

  1. Nadzor in upravljanje omrežij Wi-Fi

    OpenAIRE

    PEKEVSKI, BOJAN

    2016-01-01

    Iz današnje perspektive Wi-Fi dostop je zelo pomemben za vsakogar. Uporaba interneta je ogromna in velik del uporabnikov dostopa preko 802.11 WLAN (Wi-Fi) omrežjih. Taka omrežja so preprosta za namestitev in so primerna tako za domače uporabnike, kot tudi za velika podjetja. Možnost uvedbe stabilnih omrežjih v krajih, kjer je žična rešitev težja za izvajanje ali pa ni tako stroškovno učinkovita, je samo eden izmed razlogov za široko uporabo WLAN-a. Današnja WLAN omrežja postajajo vse bolj ...

  2. Evaluating the Performance of IPTV over Fixed WiMAX

    Science.gov (United States)

    Hamodi, Jamil; Salah, Khaled; Thool, Ravindra

    2013-12-01

    IEEE specifies different modulation techniques for WiMAX; namely, BPSK, QPSK, 16 QAM and 64 QAM. This paper studies the performance of Internet Protocol Television (IPTV) over Fixed WiMAX system considering different combinations of digital modulation. The performance is studied taking into account a number of key system parameters which include the variation in the video coding, path-loss, scheduling service classes different rated codes in FEC channel coding. The performance study was conducted using OPNET simulation. The performance is studied in terms of packet lost, packet jitter delay, end-to-end delay, and network throughput. Simulation results show that higher order modulation and coding schemes (namely, 16 QAM and 64 QAM) yield better performance than that of QPSK.

  3. Sending Safety Video over WiMAX in Vehicle Communications

    Directory of Open Access Journals (Sweden)

    Jun Steed Huang

    2013-10-01

    Full Text Available This paper reports on the design of an OPNET simulation platform to test the performance of sending real-time safety video over VANET (Vehicular Adhoc NETwork using the WiMAX technology. To provide a more realistic environment for streaming real-time video, a video model was created based on the study of video traffic traces captured from a realistic vehicular camera, and different design considerations were taken into account. A practical controller over real-time streaming protocol is implemented to control data traffic congestion for future road safety development. Our driving video model was then integrated with the WiMAX OPNET model along with a mobility model based on real road maps. Using this simulation platform, different mobility cases have been studied and the performance evaluated in terms of end-to-end delay, jitter and visual experience.

  4. Krakówi graafikasügis / Anne Untera

    Index Scriptorium Estoniae

    Untera, Anne, 1951-

    2009-01-01

    16. septembril avatud Krakówi rahvusvahelisest graafikatriennaalist. Grand prix läks poola graafikule Joanna Piechile. Läti graafik Guntars Sietiņš pälvis Varssavi kunstiakadeemia rektori auhinna. Eestit esindavad peanäitusel Ülle Marks, Benjamin Vasserman ja Eve Kask, satelliitnäitusel "PrintArt" Katowices Tiiu Prisko ja Mati Veermets ning kutsutud osalejatega satelliitnäitusel Torunis Evi Tihemets

  5. A WiFi public address system for disaster management.

    Science.gov (United States)

    Andrade, Nicholas; Palmer, Douglas A; Lenert, Leslie A

    2006-01-01

    The WiFi Bullhorn is designed to assist emergency workers in the event of a disaster situation by offering a rapidly configurable wireless of public address system for disaster sites. The current configuration plays either pre recorded or custom recorded messages and utilizes 802.11b networks for communication. Units can be position anywhere wireless coverage exists to help manage crowds or to recall first responders from dangerous areas.

  6. Wi-Fi Tags for the Remote and Virtual Laboratory

    Directory of Open Access Journals (Sweden)

    D. Ursutiu

    2008-04-01

    Full Text Available With the advancement of computer technologiesto faster processors and more memory, the WorldWideWeb,wireless communication, and miniaturization of sensortechnology, it is now possible to simulate and executeengineering and science laboratory projects on a remotecomputer. With Internet connection, students have access to"virtual laboratories" via the www, experiment-orientedproblems can be now offered without the overhead incurredwhen maintaining a full laboratory. This paper investigatesthe opportunity that a new wireless sensor technologybrings to remote laboratories.G2 Microsystems of Campbell, California, USA, released in2007 the first ever ultra-low power Wi-Fi System on a Chip(SoC named G2C501. This SoC includes a 32-bit CPU,crypto accelerator, real-time clock and a versatile sensorinterface that can serve as a standalone host subsystem. TheG2C501 goes beyond today’s basic radio frequencyidentification (RFID technology to offer intelligent trackingand sensor capabilities that leverage IEEE 802.11 (Wi-Finetworks. Due to its support for multiple locationtechnologies, small form factor and ultra-low powerconsumption, the G2C502 SoC can be integrated into Wi-Fisensor tags that lower cost of ownership and meet the needsof a variety of industries including consumer electronics,pharmaceuticals, chemical manufacturing, cold chain andmore.A battery powered, small size ultra low-power Wi-Fiwireless measurement node name IP Sensor has been builtusing the G2C501 SoC. Sensors for measurement oftemperature, humidity, light, and vibration or motion arecurrently mounted on the IP Sensor board. The node is ableto read a sensor and send data to the network by using anIP-based application protocol such as UDP.This paper describes the new IP Sensor

  7. Analisis Throughput Varian TCP Pada Model Jaringan WiMAX

    Directory of Open Access Journals (Sweden)

    Medi Taruk

    2016-07-01

    Full Text Available Transmission Control Protocol (TCP is a protocol that works at the transport layer of the OSI model. TCP was originally designed more destined for a wired network. However, to meet the need for the development of a very fast network technology based on the needs of the use by the user, it needs further development to the use of TCP on wireless devices. One implementation of a wireless network based on Worldwide Interoperability for Microwave Access (WiMAX network is a model that offers a variety advantage, particularly in terms of access speed. In this case, use NS-2 to see throughput at TCP variants tested, namely TCP-Tahoe, TCP-Reno, TCP-Vegas, and TCP-SACK over WiMAX network model, with few observations scenarios. The first is a look at each of these variants throughput of TCP when only one particular variant of the work in the network. Second observe all variants of TCP throughput at the same time and have the equivalent QoS, but with the possibility of a small congestion based on the capacity of the link is made sufficient. Third observed throughput with multi congestion. In WiMAX network has scheduling services are UGS, rtPS and ertPS using UDP protocol and nrtPS and BE using the TCP Protocol. By using the software network simulator (NS-2 to obtain performance comparison TCP protocol-based services on the WiMAX network with QoS parameters are throughput, packet loss, fairness and time delay.

  8. The genesis of WiFi and its applications

    CERN Multimedia

    CERN. Geneva

    2008-01-01

    In 1985 changes to US regulations caused a paradigm shift by permitting the use of radio spectrum for devices that did not need to have an end-user license. After a few years, products appeared on the market and a group developed a standard for broadband wireless communications among computers. The presentation will explain how the standard developed and was adopted by the Wi-Fi Alliance, as well as the global harmonization and expansion of the available radio spectrum to over half a GHz. The success of Wi-Fi and user innovation and initiatives makes it a vehicle to bring broadband internet to rural areas both in developing as well as in developed countries. Vic Hayes is a Senior Research Fellow at the Delft University of Technology and is writing a book titled "The genesis of Wi-Fi and the road toward global success". He holds a BSEE and joined NCR in the Netherlands in 1974. He co-established and chaired the IEEE 802.11 Standards Working Group for Wireless Local Area Networks and became known as the "Fathe...

  9. HDACs and the senescent phenotype of WI-38 cells

    Directory of Open Access Journals (Sweden)

    Noonan Emily J

    2005-10-01

    Full Text Available Abstract Background Normal cells possess a limited proliferative life span after which they enter a state of irreversible growth arrest. This process, known as replicative senescence, is accompanied by changes in gene expression that give rise to a variety of senescence-associated phenotypes. It has been suggested that these gene expression changes result in part from alterations in the histone acetylation machinery. Here we examine the influence of HDAC inhibitors on the expression of senescent markers in pre- and post-senescent WI-38 cells. Results Pre- and post-senescent WI-38 cells were treated with the HDAC inhibitors butyrate or trichostatin A (TSA. Following HDAC inhibitor treatment, pre-senescent cells increased p21WAF1 and β-galactosidase expression, assumed a flattened senescence-associated morphology, and maintained a lower level of proteasome activity. These alterations also occurred during normal replicative senescence of WI-38 cells, but were not accentuated further by HDAC inhibitors. We also found that HDAC1 levels decline during normal replicative senescence. Conclusion Our findings indicate that HDACs impact numerous phenotypic changes associated with cellular senescence. Reduced HDAC1 expression levels in senescent cells may be an important event in mediating the transition to a senescent phenotype.

  10. Indoor positioning using differential Wi-Fi lateration

    Science.gov (United States)

    Retscher, Guenther; Tatschl, Thomas

    2017-12-01

    For Wi-Fi positioning usually location fingerprinting or (tri)lateration are employed whereby the received signal strengths (RSSs) of the surrounding Wi-Fi Access Points (APs) are scanned on the mobile devices and used to perform localization. Within the scope of this study, the position of a mobile user is determined on the basis of lateration. Two new differential approaches are developed and compared to two common models, i.e., the one-slope and multi-wall model, for the conversion of the measured RSS of the Wi-Fi signals into ranges. The two novel methods are termed DWi-Fi as they are derived either from the well-known DGPS or VLBI positioning principles. They make use of a network of reference stations deployed in the area of interest. From continuous RSS observations on these reference stations correction parameters are derived and applied by the user in real-time. This approach leads to a reduced influence of temporal and spatial variations and various propagation effects on the positioning result. In practical use cases conducted in a multi-storey office building with three different smartphones, it is proven that the two DWi-Fi approaches outperform the common models as static positioning yielded to position errors of about 5 m in average under good spatial conditions.

  11. Discovering the Azores front/current system with SeaWiFS imagery

    Science.gov (United States)

    Martins, Ana M.; Bashmachnikov, Igor L.; Lafon, Virginie M.; Mendonca, Ana H.; Jose, Felix; Figueiredo, Miguel P.; Macedo, Luis M.

    2004-11-01

    Ocean Colour (OC) sensors have been primarily used in biological studies. More recently, OC information has been attracting the attention of oceanographers, as a potential method for revealing physical structures in the ocean. In this study, OC data obtained from SeaWiFS imagery is used, for the first time, to detect the weak Azores Current (AzC) and the associated Azores Front (AzF). Previous studies show that the frontal interface is well seen on SST imagery only during the cold season, while it is disguised during the warm season through the formation of a strong seasonal thermocline. With SeaWiFS imagery, the frontal interface is well identified around 34° N as an asymmetric zonally stretched band of higher near-surface chlorophyll a (CHL a) values north of the AzF, accompanied by a sharp decrease to the south. Quasi-stationary meanders, previously derived from SST fields for the same region, are also well observed in OC imagery. Monthly-averaged Chl a along a meridional cross-section shows that, from spring to autumn, the front is clearly visible. In winter, differences across the front are less pronounced, and the front is more easily identified on SST fields. OC gradients weaken to the east, corresponding to the general weakening of the AzC. In situ CTD data reveal a sharp and meandering thermohaline and dissolved oxygen front ocated at 33-34.5° N and 31° W. This study suggests that OC imagery, combined with other sensors, provide an important tool to investigate ocean dynamic variability, by helping to detect frontal zones with great precision.

  12. Hybrid stars

    Indian Academy of Sciences (India)

    physics pp. 753-756. Hybrid stars. AsHOK GOYAL. Department of Physics and Astrophysics, University of Delhi, Delhi 110 007, India. Abstract. Recently there have been important developments in the determination of neutron ... be composed of normal nuclear matter with hyperons and/or condensed mesons. The matter at ...

  13. Star Conquest

    OpenAIRE

    Porrino Serrano, Fernando

    2014-01-01

    Star Conquest es un juego de mesa "print n play" de estrategia por turnos para dos o tres jugadores. Éste proyecto consiste en tomar el juego de mesa original y desarrollar una adaptación en forma de videojuego para distintas plataformas

  14. Hybrid stars

    Indian Academy of Sciences (India)

    Hybrid stars. AsHOK GOYAL. Department of Physics and Astrophysics, University of Delhi, Delhi 110 007, India. Abstract. Recently there have been important developments in the determination of neutron ... number and the electric charge. ... available to the system to rearrange concentration of charges for a given fraction of.

  15. Pulsating stars

    CERN Document Server

    Catelan, M?rcio

    2014-01-01

    The most recent and comprehensive book on pulsating stars which ties the observations to our present understanding of stellar pulsation and evolution theory.  Written by experienced researchers and authors in the field, this book includes the latest observational results and is valuable reading for astronomers, graduate students, nuclear physicists and high energy physicists.

  16. Carbon stars

    International Nuclear Information System (INIS)

    Azzopardi, M.; Lequeux, J.; Rebeirot, E.

    1985-01-01

    Several stars of this type have just been detected in galaxies where they were not suspected and where they reveal a recent activity not really corresponding to current ideas. Data given by these observations allow the astrophysicists to improve the galaxy evolution models, in particular the evolution model of our galaxy [fr

  17. Star Products and Applications

    OpenAIRE

    Iida, Mari; Yoshioka, Akira

    2010-01-01

    Star products parametrized by complex matrices are defined. Especially commutative associative star products are treated, and star exponentials with respect to these star products are considered. Jacobi's theta functions are given as infinite sums of star exponentials. As application, several concrete identities are obtained by properties of the star exponentials.

  18. Analisis Swot sebagai Strategi Meningkatkan Daya Saing pada Bisnis Usaha Sepatu (Kasus Toko Sepatu Stars Cabang Marpoyan Pekanbaru)

    OpenAIRE

    ", Kasmiruddin; Armi, CVhintya

    2014-01-01

    Stars shoes shop at Marpoyan Pekanbaru department are one of trade business that work under Stars International Company in Surabaya. This trade business work in footwear sector or retail business. More rivalry in trade business that make a challenge for this trade business to always get compete and hold out into rivalry business.This research are purpose to know SWOT analysis and strategy for increase competitiveness along with assembling SWOT analysis. This research are description method wi...

  19. Streaming Multimedia via Overlay Networks using Wi-Fi Peer-to-Peer Connections

    DEFF Research Database (Denmark)

    Poderys, Justas; Soler, José

    2017-01-01

    Short range ad-hoc wireless networks can be used to deliver streaming multimedia for information, entertainment and advertisement purposes. To enable short-range communication between various devices, the Wi-Fi Alliance proposed an extension to the IEEE802.11 Wi-Fi standard called Wi-Fi Peer......-to-Peer (P2P). It allows compliant devices to form ad-hoc communication groups without interrupting conventional access point-based Wi-Fi communication. This paper proposes to use Wi-Fi P2P connectivity to distribute streaming multimedia in ah-hoc formed user groups. The exchange of multimedia data...... is performed by forming an overlay network using Peer-to-Peer Streaming Peer Protocol (PPSPP). In order to make PPSPP function over WiFi P2P connections, this paper proposes a number of changes to the protocol. The performance of the proposed system is evaluated using a computer networks emulator...

  20. Wave Star

    DEFF Research Database (Denmark)

    Kramer, Morten; Frigaard, Peter; Brorsen, Michael

    Nærværende rapport beskriver foreløbige hovedkonklusioner på modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star i perioden 13/9 2004 til 12/11 2004.......Nærværende rapport beskriver foreløbige hovedkonklusioner på modelforsøg udført på Aalborg Universitet, Institut for Vand, Jord og Miljøteknik med bølgeenergianlægget Wave Star i perioden 13/9 2004 til 12/11 2004....

  1. Strangeon Stars

    Science.gov (United States)

    Lu, Jiguang; Xu, Renxin

    Stable micro-nucleus is 2-flavored (u and d), whereas stable macro-nucleus could be 3-flavored (u, d, and s) if the light flavor symmetry restores there. Nucleons are the constituent of a nucleus, while strangeons are named as the constituent of 3-flavored baryonic matter. Gravity-compressed baryonic object created after core-collapse supernova could be strangeon star if the energy scale (˜0.5 GeV) cannot be high enough for quark deconfinement and if there occurs 3-flavor symmetry restoration. Strangeon stars are explained here, including their formation and manifestation/identification. Much work, coupled with effective micro-model of strangeon matter, is needed to take advantage of the unique opportunities advanced facilities will provide.

  2. WiMAX security and quality of service an end-to-end perspective

    CERN Document Server

    Tang, Seok-Yee; Sharif, Hamid

    2010-01-01

    WiMAX is the first standard technology to deliver true broadband mobility at speeds that enable powerful multimedia applications such as Voice over Internet Protocol (VoIP), online gaming, mobile TV, and personalized infotainment. WiMAX Security and Quality of Service, focuses on the interdisciplinary subject of advanced Security and Quality of Service (QoS) in WiMAX wireless telecommunication systems including its models, standards, implementations, and applications. Split into 4 parts, Part A of the book is an end-to-end overview of the WiMAX architecture, protocol, and system requirements.

  3. On the Issues and Challenges of Fiber-Wireless (Fi-Wi Networks

    Directory of Open Access Journals (Sweden)

    Harry Tin Win

    2013-01-01

    Full Text Available The objective of this article is to present various aspects of Fiber-Wireless (Fi-Wi networks, which is a technology of current interest of the researchers. Fiber-wireless technology, known in short as “Fi-Wi,” is a combination of optical-fiber-based network and wireless network. Fi-Wi has recently come forward as one of the emerging future network technologies yet the term is often mixed up with wireless-fidelity (Wi-Fi technology. In fact, Wi-Fi network could be included in a Fi-Wi architecture. Due to the unfamiliarity with the term, “Fi-Wi” and similar sounding commonly known “Wi-Fi,” many students, even academics and practitioners sometimes may not be able to differentiate between these. In the recent years, a good number of works on various issues of Fi-Wi have come out, but an overall survey with the latest advancements in the area is yet to be found. Hence, in this work, we analyze various issues and challenges of implementing Fi-Wi networks in practical scenarios to allow researchers to find future directions of research and general readers to understand the issues better.

  4. Radiofrequency exposure from wireless LANs utilizing Wi-Fi technology.

    Science.gov (United States)

    Foster, Kenneth R

    2007-03-01

    This survey measured radiofrequency (RF) fields from wireless local area networks (WLANs) using Wi-Fi technology against a background of RF fields in the environment over the frequency range 75 MHz-3 GHz. A total of 356 measurements were conducted at 55 sites (including private residences, commercial spaces, health care and educational institutions, and other public spaces) in four countries (U.S., France, Germany, Sweden). Measurements were conducted under conditions that would result in the higher end of exposures from such systems. Where possible, measurements were conducted in public spaces as close as practical to the Wi-Fi access points. Additional measurements were conducted at a distance of approximately 1 m from a laptop while it was uploading and downloading large files to the WLAN. This distance was chosen to allow a useful comparison of fields in the far-field of the antenna in the laptop, and give a representative measure of the exposure that a bystander might receive from the laptop. The exposure to the user, particularly if the antenna of the client card were placed against his or her body, would require different measurement techniques beyond the scope of this study. In all cases, the measured Wi-Fi signal levels were very far below international exposure limits (IEEE C95.1-2005 and ICNIRP) and in nearly all cases far below other RF signals in the same environments. An discusses technical aspects of the IEEE 802.11 standard on which WLANs operate that are relevant to determining the levels of RF energy exposure from WLANs. Important limiting factors are the low operating power of client cards and access points, and the low duty cycle of transmission that normally characterizes their operation.

  5. Spectroscopy of λ Bootis stars

    International Nuclear Information System (INIS)

    Heiter, U.

    2000-05-01

    λ Bootis stars are defined as metal-poor Population I A- to F-type stars, which exhibit nearly solar element abundance for C, N, O and S (e.g. Paunzen E., Weiss W.W., Heiter U. and North P., 1997, A and AS 123, 93). The classification of λ Bootis stars based on photometric indices or low resolution spectra is not sufficient for a final decision concerning a membership to this group. A detailed spectroscopic investigation is necessary to rule out stars with similar classification spectra but different abundance patterns. Therefore a program on abundance analyses of λ Bootis candidates was established, which makes use of a software package that enables the analysis of high signal-to-noise spectra with high resolution (R = 30000 to 60000). The first part of the thesis deals with the effects of using several different codes for the model atmosphere calculation on the synthetic spectra of three stars with different atmospheric parameters and degrees of underabundance. It is shown that using opacity distribution functions (ODFs) calculated for individual abundance patterns instead of pretabulated solar scaled ODFs does not change the synthetic spectra significantly. On the other hand, for the coolest star the treatment of overshooting within the calculation of the convective flux has a non-negligible influence on the derived abundance. Taking these findings into account, the results of the application of the abundance analysis tools on eleven candidate λ Bootis stars are presented in the second part of the thesis. They are based on high resolution echelle spectra obtained by the author at the Osservatorio Astronomico di Padova (Asiago, Italy). Two of these stars were found to be spectroscopic binaries during the analysis. Particular consideration is given to the estimation of the errors of the derived abundance and the problems faced when examining stars with large differences in abundance of different elements and large rotational broadening of the spectral lines

  6. WI-CERFP Respiratory Protection Optimization: A Detailed Analysis

    Science.gov (United States)

    2015-12-01

    AU/ACSC/2015 AIR COMMAND AND STAFF COLLEGE AIR UNIVERSITY WI-CERFP RESPIRATORY PROTECTION OPTIMIZATION: A DETAILED ANALYSIS By...vii INTRODUCTION………………………………………………………………………….. 1 RESPIRATORY PROTECTION...3 Theory of Respiratory Protection…………………………………………………… 3 Air Purifying Respiratory – Detailed Configuration……………………………....... 3 Powered Air

  7. STABILIZACIJA KVADROKOPTERJA IN DALJINSKI WI-FI VIDEO NADZOR TERENA

    OpenAIRE

    Zlatarek, Miha

    2015-01-01

    V diplomskem delu smo se ukvarjali s težavnostjo izdelave kvadrokopterja in nastavitve PID parametrov za stabilizacijo letenja kvadrokopterja. Poglobiti smo se morali v samo mehansko redukcijo tresljajev, saj prenašamo video signale s pomočjo mikroračunalnika Raspberry Pi ter PiCam preko Wi-Fi omrežja. Preverili smo možnosti daljinskega video nadzora kvadrokopterja preko Raspberry Pi platforme. Opisana je celotna sestava kvadrokopterja, z opisom pripadajočih delov, ter celoten postopek na...

  8. RRM Strategies in LTE&WiMAX Interworking System

    DEFF Research Database (Denmark)

    Zakrzewska, Anna; Ruepp, Sarah Renée; Berger, Michael Stübert

    high quality streaming video. In order to provide those demanding real-time multimedia and very high data rates, scarce radio resources must be used effectively to maximize the channel utilization. The presentation will focus on scheduling techniques possibly adaptable to dynamically changing network......, that could be applied in 4G systems (LTE interworking with WiMAX is considered). Furthermore, it will also discuss the Radio Resource Management (RRM) problem addressing the challenges of designing a RRM system for such a multi-RAT wireless environment. Different functionalities and possibilities...

  9. Star Formation in the Gulf of Mexico

    OpenAIRE

    Armond, Tina; Reipurth, Bo; Bally, John; Aspin, Colin

    2011-01-01

    We present an optical/infrared study of the dense molecular cloud, L935, dubbed "The Gulf of Mexico", which separates the North America and the Pelican nebulae, and we demonstrate that this area is a very active star forming region. A wide-field imaging study with interference filters has revealed 35 new Herbig-Haro objects in the Gulf of Mexico. A grism survey has identified 41 Halpha emission-line stars, 30 of them new. A small cluster of partly embedded pre-main sequence stars is located a...

  10. The Solar system.Stars and constellations

    Science.gov (United States)

    Horia Minda, Octavian

    2017-04-01

    It is important for students to understand what is in our Solar System. The Students need to know that there are other things besides the Earth, Sun and Moon in the solar sky. The students will learn about the other eight planets and a few other celestial objects like stars and constellations. Constellations are useful because they can help people to recognize stars in the sky. By looking for patterns, the stars and locations can be much easier to spot. The constellations had uses in ancient times. They were used to help keep track of the calendar. This was very important so that people knew when to plant and harvest crops. Another important use for constellations was navigation. By finding Ursa Minor it is fairly easy to spot the North Star (Polaris). Using the height of the North Star in the sky, navigators could figure out their latitude helping ships to travel across the oceans. Objective: 1. The students will be introduced to the origin of the stars they see at night. 2. They will learn that there are groups of stars called constellations. The students will individually create their own constellations. They will be given the chance to tell the class a small story explaining their constellation. Evaluation of Children: The children will be evaluated through the creation of their constellations and ability to work in groups on the computers.

  11. Accesso Wi-Fi federato dell'Area della Ricerca di Pisa WiFi@PiCNR

    OpenAIRE

    Gebrehiwot, Abraham; De Vita, Andrea

    2011-01-01

    The CNR Research Area of Pisa has a Wi-FI coverage in the campus. The wireless network is designed and implemented by the Institute of Informatics and Telematics of CNR which is in charge of managing the network infrastructure and also providing a number of other services to researchers in the campus. The wireless network is a centralized solution based on Cisco Wireless LAN Controller (WLC). In the campus area various wireless networks are defined, including the SSID "guest" with a Captive P...

  12. Inferring Stop-Locations from WiFi.

    Directory of Open Access Journals (Sweden)

    David Kofoed Wind

    Full Text Available Human mobility patterns are inherently complex. In terms of understanding these patterns, the process of converting raw data into series of stop-locations and transitions is an important first step which greatly reduces the volume of data, thus simplifying the subsequent analyses. Previous research into the mobility of individuals has focused on inferring 'stop locations' (places of stationarity from GPS or CDR data, or on detection of state (static/active. In this paper we bridge the gap between the two approaches: we introduce methods for detecting both mobility state and stop-locations. In addition, our methods are based exclusively on WiFi data. We study two months of WiFi data collected every two minutes by a smartphone, and infer stop-locations in the form of labelled time-intervals. For this purpose, we investigate two algorithms, both of which scale to large datasets: a greedy approach to select the most important routers and one which uses a density-based clustering algorithm to detect router fingerprints. We validate our results using participants' GPS data as well as ground truth data collected during a two month period.

  13. Effective Bandwidth Allocation for WiMAX Mesh Network

    Directory of Open Access Journals (Sweden)

    Hung-Chin Jang

    2010-04-01

    Full Text Available The aim of this paper is to reduce the media access delay in a WiMAX mesh network. We observe that as the number of subscriber stations (SS in a neighborhood increases, the processes of transmission opportunity (TO competition and 3- way handshake are easy to fail. This may degrade transmission efficiency and increase packet transmission delay. Besides, the minislot allocation defined in the WiMAX mesh mode may cause many lower priority services reserve earlier minislots than that of higher priority services like rtPS. This may cause great negative impact on delay-sensitive traffic. In this paper, we design a QoS classifier to enqueue packets according to different QoS service classes, present a dynamic holdoff exponent mechanism to reduce control subframe delay, and propose a Neighborhood-Based Minislot Allocation (NBMA mechanism to reduce data subframe delay. Simulations show that the proposed methodology outperforms that of IEEE 802.16 and Baye's DynExp in delay, jitter and throughput.

  14. Automatic Construction of Wi-Fi Radio Map Using Smartphones

    Science.gov (United States)

    Liu, Tao; Li, Qingquan; Zhang, Xing

    2016-06-01

    Indoor positioning could provide interesting services and applications. As one of the most popular indoor positioning methods, location fingerprinting determines the location of mobile users by matching the received signal strength (RSS) which is location dependent. However, fingerprinting-based indoor positioning requires calibration and updating of the fingerprints which is labor-intensive and time-consuming. In this paper, we propose a visual-based approach for the construction of radio map for anonymous indoor environments without any prior knowledge. This approach collects multi-sensors data, e.g. video, accelerometer, gyroscope, Wi-Fi signals, etc., when people (with smartphones) walks freely in indoor environments. Then, it uses the multi-sensor data to restore the trajectories of people based on an integrated structure from motion (SFM) and image matching method, and finally estimates location of sampling points on the trajectories and construct Wi-Fi radio map. Experiment results show that the average location error of the fingerprints is about 0.53 m.

  15. Effects of Implementing Adaptable Channelization in Wi-Fi Networks

    Directory of Open Access Journals (Sweden)

    Abid Hussain

    2016-01-01

    Full Text Available The unprecedented increase of wireless devices is now facing a serious threat of spectrum scarcity. The situation becomes even worse due to inefficient frequency distribution protocols, deployed in trivial Wi-Fi networks. The primary source of this inefficiency is static channelization used in wireless networks. In this work, we investigate the use of dynamic and flexible channelization, for optimal spectrum utilization in Wi-Fi networks. We propose optimal spectrum sharing algorithm (OSSA and analyze its effect on exhaustive list of essential network performance measuring parameters. The elementary concept of the proposed algorithm lies in the fact that frequency spectrum should be assigned to any access point (AP based on its current requirement. The OSSA algorithm assigns channels with high granularity, thus maximizing spectrum utilization by more than 20% as compared to static width channel allocation. This optimum spectrum utilization, in turn, increases throughput by almost 30% in many deployment scenarios. The achieved results depict considerable decrease in interference, while simultaneously increasing range. Similarly signal strength values at relatively longer distances improve significantly at narrower channel widths while simultaneously decreasing bit error rates. We found that almost 25% reduction in interference is possible in certain scenarios through proposed algorithm.

  16. Inferring Stop-Locations from WiFi.

    Science.gov (United States)

    Wind, David Kofoed; Sapiezynski, Piotr; Furman, Magdalena Anna; Lehmann, Sune

    2016-01-01

    Human mobility patterns are inherently complex. In terms of understanding these patterns, the process of converting raw data into series of stop-locations and transitions is an important first step which greatly reduces the volume of data, thus simplifying the subsequent analyses. Previous research into the mobility of individuals has focused on inferring 'stop locations' (places of stationarity) from GPS or CDR data, or on detection of state (static/active). In this paper we bridge the gap between the two approaches: we introduce methods for detecting both mobility state and stop-locations. In addition, our methods are based exclusively on WiFi data. We study two months of WiFi data collected every two minutes by a smartphone, and infer stop-locations in the form of labelled time-intervals. For this purpose, we investigate two algorithms, both of which scale to large datasets: a greedy approach to select the most important routers and one which uses a density-based clustering algorithm to detect router fingerprints. We validate our results using participants' GPS data as well as ground truth data collected during a two month period.

  17. AUTOMATIC CONSTRUCTION OF WI-FI RADIO MAP USING SMARTPHONES

    Directory of Open Access Journals (Sweden)

    T. Liu

    2016-06-01

    Full Text Available Indoor positioning could provide interesting services and applications. As one of the most popular indoor positioning methods, location fingerprinting determines the location of mobile users by matching the received signal strength (RSS which is location dependent. However, fingerprinting-based indoor positioning requires calibration and updating of the fingerprints which is labor-intensive and time-consuming. In this paper, we propose a visual-based approach for the construction of radio map for anonymous indoor environments without any prior knowledge. This approach collects multi-sensors data, e.g. video, accelerometer, gyroscope, Wi-Fi signals, etc., when people (with smartphones walks freely in indoor environments. Then, it uses the multi-sensor data to restore the trajectories of people based on an integrated structure from motion (SFM and image matching method, and finally estimates location of sampling points on the trajectories and construct Wi-Fi radio map. Experiment results show that the average location error of the fingerprints is about 0.53 m.

  18. A Vanishing Star Revisited

    Science.gov (United States)

    1999-07-01

    VLT Observations of an Unusual Stellar System Reinhold Häfner of the Munich University Observatory (Germany) is a happy astronomer. In 1988, when he was working at a telescope at the ESO La Silla observatory, he came across a strange star that suddenly vanished off the computer screen. He had to wait for more than a decade to get the full explanation of this unusual event. On June 10-11, 1999, he observed the same star with the first VLT 8.2-m Unit Telescope (ANTU) and the FORS1 astronomical instrument at Paranal [1]. With the vast power of this new research facility, he was now able to determine the physical properties of a very strange stellar system in which two planet-size stars orbit each other. One is an exceedingly hot white dwarf star , weighing half as much as the Sun, but only twice as big as the Earth. The other is a much cooler and less massive red dwarf star , one-and-a-half times the size of planet Jupiter. Once every three hours, the hot star disappears behind the other, as seen from the Earth. For a few minutes, the brightness of the system drops by a factor of more than 250 and it "vanishes" from view in telescopes smaller than the VLT. A variable star named NN Serpentis ESO PR Photo 30a/99 ESO PR Photo 30a/99 [Preview - JPEG: 400 x 468 pix - 152k] [Normal - JPEG: 800 x 936 pix - 576k] [High-Res - JPEG: 2304 x 2695 pix - 4.4M] Caption to ESO PR Photo 30a/99 : The sky field around the 17-mag variable stellar system NN Serpentis , as seen in a 5 sec exposure through a V(isual) filter with VLT ANTU and FORS1. It was obtained just before the observation of an eclipse of this unsual object and served to centre the telescope on the corresponding sky position. The field shown here measures 4.5 x 4.5 armin 2 (1365 x 1365 pix 2 ; 0.20 arcsec/pix). The field is somewhat larger than that shown in Photo 30b/99 and has the same orientation to allow comparison: North is about 20° anticlockwise from the top and East is 90° clockwise from that direction. The

  19. Complete Genome Sequence of Lactobacillus curvatus Strain WiKim38 Isolated from Kimchi

    Science.gov (United States)

    Lee, Se Hee; Jung, Min Young; Song, Jung-Hee; Lee, Moeun

    2017-01-01

    ABSTRACT Lactobacillus curvatus WiKim38 is a potential probiotic strain isolated from kimchi, a traditional Korean fermented food. The complete genome of the WiKim38 strain consisted of a circular chromosome of 1,940,170 bp in length with a G+C content of 41.93%. PMID:28473381

  20. FeltRadio – Experiencing Community-generated WiFi Activities

    DEFF Research Database (Denmark)

    Fritsch, Jonas; Gronvall, Erik

    2016-01-01

    FeltRadio is a portable technology for sensing WiFi through sensorial augmentation and Electric Muscle Stimulation (EMS). The technology enables its wearer to sensorially engage with the radio waves and WiFi activities that have become an integrated part of our everyday lives. The sensorial...

  1. The making of the Women in Biology forum (WiB) at Bioclues.

    Science.gov (United States)

    Singhania, Reeta Rani; Madduru, Dhatri; Pappu, Pranathi; Panchangam, Sameera; Suravajhala, Renuka; Chandrasekharan, Mohanalatha

    2014-01-01

    The Women in Biology forum (WiB) of Bioclues (India) began in 2009 to promote and support women pursuing careers in bioinformatics and computational biology. WiB was formed in order to help women scientists deprived of basic research, boost the prominence of women scientists particularly from developing countries, and bridge the gender gap to innovation. WiB has also served as a platform to highlight the work of established female scientists in these fields. Several award-winning women researchers have shared their experiences and provided valuable suggestions to WiB. Headed by Mohanalatha Chandrasekharan and supported by Dr. Reeta Rani Singhania and Renuka Suravajhala, WiB has seen major progress in the last couple of years particularly in the two avenues Mentoring and Research, off the four avenues in Bioclues: Mentoring, Outreach, Research and Entrepreneurship (MORE). In line with the Bioclues vision for bioinformatics in India, the WiB Journal Club (JoC) recognizes women scientists working on functional genomics and bioinformatics, and provides scientific mentorship and support for project design and hypothesis formulation. As a part of Bioclues, WiB members practice the group's open-desk policy and its belief that all members are free to express their own thoughts and opinions. The WiB forum appreciates suggestions and welcomes scientists from around the world to be a part of their mission to encourage women to pursue computational biology and bioinformatics.

  2. The making of the Women in Biology forum (WiB at Bioclues.

    Directory of Open Access Journals (Sweden)

    Reeta Rani Singhania

    2014-01-01

    Full Text Available The Women in Biology forum (WiB of Bioclues (India began in 2009 to promote and support women pursuing careers in bioinformatics and computational biology. WiB was formed in order to help women scientists deprived of basic research, boost the prominence of women scientists particularly from developing countries, and bridge the gender gap to innovation. WiB has also served as a platform to highlight the work of established female scientists in these fields. Several award-winning women researchers have shared their experiences and provided valuable suggestions to WiB. Headed by Mohanalatha Chandrasekharan and supported by Dr. Reeta Rani Singhania and Renuka Suravajhala, WiB has seen major progress in the last couple of years particularly in the two avenues Mentoring and Research, off the four avenues in Bioclues: Mentoring, Outreach, Research and Entrepreneurship (MORE. In line with the Bioclues vision for bioinformatics in India, the WiB Journal Club (JoC recognizes women scientists working on functional genomics and bioinformatics, and provides scientific mentorship and support for project design and hypothesis formulation. As a part of Bioclues, WiB members practice the group's open-desk policy and its belief that all members are free to express their own thoughts and opinions. The WiB forum appreciates suggestions and welcomes scientists from around the world to be a part of their mission to encourage women to pursue computational biology and bioinformatics.

  3. Mārketinga koncepcijas izveide Wi-Fi pakalpojumam Latvijā

    OpenAIRE

    Zauers, Mārtiņš 

    2008-01-01

    Maģistra darbā Wi-Fi mārketinga koncepcijas izveide Latvijā autors apkopo teoriju par mārketingu un tā koncepcijas izveidi, analizē tehnisko literatūru par Wi-Fi, Wi-Fi vēsturi, izveidošanos Latvijā un apkopo datus par Wi-Fi tirgus attīstību Latvijā, kā arī Lattelecom Wi-Fi pakalpojumu. Pētījuma mērķis ir analizēt un vērtēt Lattelecom Wi-Fi pakalpojuma pieejamību Latvijā un izstrādāt tā mārketinga koncepciju. Analizējot Wi-Fi pakalpojuma tirgu Latvijā, pētījuma daļā autors izveido Wi-Fi p...

  4. Indoor path loss prediction for Wi-Fi network in ultrahigh frequency ...

    African Journals Online (AJOL)

    In this work, Wi-Fi received signal strength was monitored in an indoor environment at 2437 MHz in ultrahigh frequency band of channel 6. The received signal strength was compressed, decomposed, filtered and reconstructed using one dimensional multi – resolution technique in order to predict how Wi-Fi received signal ...

  5. Enhancing Teaching and Learning Wi-Fi Networking Using Limited Resources to Undergraduates

    Science.gov (United States)

    Sarkar, Nurul I.

    2013-01-01

    Motivating students to learn Wi-Fi (wireless fidelity) wireless networking to undergraduate students is often difficult because many students find the subject rather technical and abstract when presented in traditional lecture format. This paper focuses on the teaching and learning aspects of Wi-Fi networking using limited hardware resources. It…

  6. A pathway to solving the Wi-Fi Tragedy of the Commons in apartment blocks

    NARCIS (Netherlands)

    Hartog, F. Den; Kemper, P.L.; Boltjes, B.; Raschella, A.; Bouhafs,F.; Seyedebrahimi, M.

    2017-01-01

    Surprisingly little research has quantified the severity of Wi-Fi congestion in densely populated areas. We performed a high-fidelity 3D simulation of the performance of a realistic Wi-Fi deployment in a typical apartment block. Our results show that congestion leads to significant loss of

  7. Noteworthy lichen species in Poland collected in the Świętokrzyski National Park

    Directory of Open Access Journals (Sweden)

    Anna Łubek

    2014-08-01

    Full Text Available In this paper 25 species of the lichens new to the Świętokrzyski National Park are presented on the basis of recent collection and revision of the herbarial material from this arc. Some of these species are new to the Świętokrzykie Mountains and one have not been recorded in Poland so far.

  8. Passive WiFi monitoring of the rhythm of the campus

    NARCIS (Netherlands)

    Kalogianni, E.; Sileryte, R.; Lam, M.; Zhou, K.; Van der Ham, M.; Van der Spek, S.C.; Verbree, E.

    2015-01-01

    Within this research-driven project, passive WiFi monitoring of WiFi enabled devices was used to detect users (students, employees, visitors) of buildings at the campus of Delft University of Technology to gain insight into the Rhythm of the Campus: the occupation, duration of stay and moving

  9. LTE/Wi-Fi Coexistence in 5 GHz ISM Spectrum: Issues, Solutions and Perspectives

    DEFF Research Database (Denmark)

    Abinader, Fuad; A. de Sousa Jr., Vicente; Choudhurry, Sayantan

    2018-01-01

    on the unlicensed band. Wi-Fi technology is widespread and also operates in the 5 GHz ISM spectrum bands, which may bring performance issues due to the coexistence of both technologies in the same spectrum band. This work is dedicated to the study of coexistence between LTE and Wi-Fi access systems operating in 5...

  10. WiFi in Schools, Electromagnetic Fields and Cell Phones: Alberta Health Fact Sheet

    Science.gov (United States)

    Alberta Education, 2012

    2012-01-01

    Wireless devices and the networks that support them are becoming more common in Alberta schools. WiFi is a wireless networking technology that allows computers and other devices to communicate over a wireless signal. Typically the signal is carried by radio waves over an area of up to 100 meters. Through the implementation of a WiFi network,…

  11. 3G Femto or 802.11g WiFi

    DEFF Research Database (Denmark)

    Jørgensen, Niels T.K.; Rodriguez Larrad, Ignacio; Elling, Jan

    2014-01-01

    In this paper HSPA Release 6 femto and IEEE 802.11g WiFi indoor data solutions are investigated from an end user perspective. Femto and WiFi access points are deployed at typical locations in an urban environment and end user performance is measured. Three key performance indicators (KPI) were...

  12. 76 FR 28073 - Notice of Inventory Completion: Logan Museum of Anthropology, Beloit College, Beloit, WI

    Science.gov (United States)

    2011-05-13

    ... Museum of Anthropology, Beloit College, Beloit, WI AGENCY: National Park Service, Interior. ACTION... the Logan Museum of Anthropology, Beloit College, Beloit, WI. The human remains were removed from... assessment of the human remains was made by the Logan Museum of Anthropology, Beloit College, professional...

  13. 76 FR 28075 - Notice of Inventory Completion: Logan Museum of Anthropology, Beloit College, Beloit, WI

    Science.gov (United States)

    2011-05-13

    ... Museum of Anthropology, Beloit College, Beloit, WI AGENCY: National Park Service, Interior. ACTION... funerary objects in the possession of the Logan Museum of Anthropology, Beloit College, Beloit, WI. The... assessment of the human remains was made by the Logan Museum of Anthropology, Beloit College, professional...

  14. Wi-Learn: An Innovative Learning Paradigm for the University of ...

    African Journals Online (AJOL)

    ... Wi-Learn, enfolds a set of mobile collaborative applications, such as wireless ile transfer, multiuser whiteboard sharing, audio and video conferencing, voting poll, SMS breaking news and revision quiz, using different wireless communication technologies. Keywords: M-learning, pervasive, education, WiFi, Bluetooth ...

  15. Simulátor pro pasivní multistatický radar s použitím WiFi/WiMAX

    OpenAIRE

    Sládek, Ondřej

    2017-01-01

    Diplomová práce se zabývá konceptem pasivního multistatického radaru. Radiolokačním signálem zkoumaného radaru je signál WiFi nebo WiMAX, který je vysílán nespolupracujícím vysílačem. Diplomová práce vyhodnocuje omezení, vyplývající z použití WiFi nebo WiMAX signálů. V rámci práce byl sestaven simulátor v prostředí Matlab, který ověřil základní myšlenku tohoto konceptu. Na základě výsledků simulací s reálnými parametry jsou formulovány závěry směrem k možnému využití WiFi/WiMAX radaru. Thi...

  16. WiFi : Une nouvelle façon de combler le fossé numérique ? | IDRC ...

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

    13 juil. 2011 ... Wi-fi: a new bridge for the digital divide? Connecting to the Internet using a simple aluminum antenna and a wireless network card coul. View moreWi-fi: a new bridge for the digital divide?

  17. A Comparative Study of the Guo Shoujing Star Catalogue and the Ulugh Beg Star Catalogue

    Science.gov (United States)

    Sun, Xiaochun; Yang, Fan; Zhao, Yongheng

    2015-08-01

    The Chinese Star Catalogue by Guo Shoujing (1231-1316) contained equatorial coordinates of 678 stars, more than doubled the number of stars in previous Chinese star catalogues. In the period 1420-1437, using astronomical instruments at Samarkand Observatory, Ulugh Beg (1394-1449) made independent observations and determined star positions of 1018 stars. An analysis of two star catalogues will show the observational techniques behind them and their accuracies. Both astronomers tried to increase accuracy of measurement by enlarging the astronomical instruments. The Chinese catalogue gives equatorial coordinates of stars. The coordinates were directly read off the armillary sphere, which was mounted equatorially mounted. Sun Xiaochun (1996) suggested that the data of the existent Guo Shoujing catalogue was actually observed around 1380, at the beginning of the Ming dynasty. The Ulugh Beg catalogue gives ecliptic coordinates of stars. Does this mean they were directly measured using an ecliptic instrument? Using Fourier analysis we discover a 3 arc minute systematic error in the declinations, which are derived from the ecliptic coordinates, suggesting the data might be first measured equatorially and then converted to ecliptic coordinates, following Ptolemaic tradition. The 3 arc minute systematic error was caused by the misalignment of the instrument's pole and celestial north pole. And the Our comparative study might throw some light on transmission of astronomical knowledge and techniques between China and Central Asia in medieval times.

  18. Effects of melatonin on Wi-Fi-induced oxidative stress in lens of rats.

    Science.gov (United States)

    Tök, Levent; Nazıroğlu, Mustafa; Doğan, Salih; Kahya, Mehmet Cemal; Tök, Ozlem

    2014-01-01

    Melatonin has been considered a potent antioxidant that detoxifies a variety of reactive oxygen species in many pathophysiological states of eye. The present study was designed to determine the effects of Wi-Fi exposure on the lens oxidant, antioxidant redox systems, as well as the possible protective effects of melatonin on the lens injury induced by electromagnetic radiation (EMR). Thirty-two rats were used in the current study and they were randomly divided into four equal groups as follows: First and second groups were cage-control and sham-control rats. Rats in third group were exposed to Wi-Fi (2.45 GHz) for duration of 60 min/day for 30 days. As in the third group, the fourth group was treated with melatonin. The one-hour exposure to irradiation in second, third and fourth took place at noon each day. Lipid peroxidation levels in the lens were slightly higher in third (Wi-Fi) group than in cage and sham control groups although their concentrations were significantly (P Wi-Fi group than in cage and sham control groups although GSH-Px (P Wi-Fi + melatonin group than in Wi-Fi group. There are poor oxidative toxic effects of one hour of Wi-Fi exposure on the lens in the animals. However, melatonin supplementation in the lens seems to have protective effects on the oxidant system by modulation of GSH-Px activity.

  19. Exposure to Radiofrequency Electromagnetic Fields From Wi-Fi in Australian Schools.

    Science.gov (United States)

    Karipidis, Ken; Henderson, Stuart; Wijayasinghe, Don; Tjong, Lydiawati; Tinker, Rick

    2017-08-01

    The increasing use of Wi-Fi in schools and other places has given rise to public concern that the radiofrequency (RF) electromagnetic fields from Wi-Fi have the potential to adversely affect children. The current study measured typical and peak RF levels from Wi-Fi and other sources in 23 schools in Australia. All of the RF measurements were much lower than the reference levels recommended by international guidelines for protection against established health effects. The typical and peak RF levels from Wi-Fi in locations occupied by children in the classroom were of the order of 10-4 and 10-2% of the exposure guidelines, respectively. Typical RF levels in the classroom were similar between Wi-Fi and radio but higher than other sources. In the schoolyard typical RF levels were higher for radio, TV and mobile phone base stations compared to Wi-Fi. The results of this study showed that the typical RF exposure of children from Wi-Fi at school is very low and comparable or lower to other sources in the environment. © The Author 2017. Published by Oxford University Press.

  20. Electromagnetic immunity of implantable pacemakers exposed to wi-fi devices.

    Science.gov (United States)

    Mattei, Eugenio; Censi, Federica; Triventi, Michele; Calcagnini, Giovanni

    2014-10-01

    The purpose of this study is to evaluate the potential for electromagnetic interference (EMI) and to assess the immunity level of implantable pacemakers (PM) when exposed to the radiofrequency (RF) field generated by Wi-Fi devices. Ten PM from five manufacturers, representative of what today is implanted in patients, have been tested in vitro and exposed to the signal generated by a Wi-Fi transmitter. An exposure setup that reproduces the actual IEEE 802.11b/g protocol has been designed and used during the tests. The system is able to amplify the Wi-Fi signal and transmits at power levels higher than those allowed by current international regulation. Such approach allows one to obtain, in case of no EMI, a safety margin for PM exposed to Wi-Fi signals, which otherwise cannot be derived if using commercial Wi-Fi equipment. The results of this study mitigate concerns about using Wi-Fi devices close to PM: none of the PM tested exhibit any degradation of their performance, even when exposed to RF field levels five times higher than those allowed by current international regulation (20 W EIRP). In conclusion, Wi-Fi devices do not pose risks of EMI to implantable PM. The immunity level of modern PM is much higher than the transmitting power of RF devices operating at 2.4 GHz.

  1. Dominant Channel Occupancy for Wi-Fi Backscatter Uplink in Industrial Internet of Things

    Directory of Open Access Journals (Sweden)

    Jung-Hyok Kwon

    2016-12-01

    Full Text Available This paper presents a dominant channel occupancy (DCO mechanism for the Wi-Fi backscatter uplink in the industrial Internet of things (IIoT. The DCO provides high-priority channel access and reliable burst transmission to the Wi-Fi backscatter devices, thereby enabling the Wi-Fi backscatter tag to deliver its tag information to the Wi-Fi reader without interference from neighboring legacy Wi-Fi devices to guarantee the timeliness and reliability of the IIoT system. For the former, we consider three types of medium access control (MAC configurations: “carrier sense multiple access with collision avoidance (CSMA/CA starting with short inter-frame space (SIFS”, “freezing of the backoff period”, and “reduced CWmin.” In addition, the DCO uses the SIFS between burst packets to guarantee reliable burst transmission. To verify the effectiveness of DCO and determine a proper value for MAC parameters, we conduct experimental simulations under IEEE 802.11n PHY/MAC environments. The simulation results show that the reduced CWmin has the most significant effect on the channel occupancy. The Wi-Fi backscatter devices achieve much higher throughput than the separate cases when two or more configurations are used simultaneously. Moreover, the results exhibit that the use of SIFS between consecutive packets supports reliable burst transmission regardless of the transmission of the legacy Wi-Fi devices in the vicinity.

  2. Exposure to radiofrequency electromagnetic fields from Wi-Fi in Australian schools

    International Nuclear Information System (INIS)

    Karipidis, Ken; Henderson, Stuart; Wijayasinghe, Don; Tjong, Lydiawati; Tinker, Rick

    2017-01-01

    The increasing use of Wi-Fi in schools and other places has given rise to public concern that the radiofrequency (RF) electromagnetic fields from Wi-Fi have the potential to adversely affect children. The current study measured typical and peak RF levels from Wi-Fi and other sources in 23 schools in Australia. All of the RF measurements were much lower than the reference levels recommended by international guidelines for protection against established health effects. The typical and peak RF levels from Wi-Fi in locations occupied by children in the classroom were of the order of 10 4 and 10 2 % of the exposure guidelines, respectively. Typical RF levels in the classroom were similar between Wi-Fi and radio but higher than other sources. In the school yard typical RF levels were higher for radio, TV and mobile phone base stations compared to Wi-Fi. The results of this study showed that the typical RF exposure of children from Wi-Fi at school is very low and comparable or lower to other sources in the environment. (authors)

  3. Dynamics of Star Polymers in Fast Extensional Flow and Stress Relaxation

    DEFF Research Database (Denmark)

    Huang, Qian; Agostini, Serena; Hengeller, Ludovica

    2016-01-01

    We confirm the observation from Ianniruberto and Marrucci [ Macromolecules 2013, 46, 267-275 ] that entangled melts of branched polystyrenes behave like linear polystyrenes in the steady state of fast extensional flow, by measuring a linear, an asymmetric star, and a symmetric star polystyrene wi...... they relax in a similar way, most likely via arm retraction, at short time, but behave differently at long time due to both the length of the arm and the branch point. The terminal relaxation is described by a Doi and Edwards based model, i.e., considering pure orientational relaxation....

  4. The making of the Women in Biology forum (WiB) at Bioclues.

    OpenAIRE

    Reeta Rani Singhania; Dhatri Madduru; Pranathi Pappu; Sameera Panchangam; Renuka Suravajhala; Mohanalatha Chandrasekharan

    2014-01-01

    The Women in Biology forum (WiB) of Bioclues (India) began in 2009 to promote and support women pursuing careers in bioinformatics and computational biology. WiB was formed in order to help women scientists deprived of basic research, boost the prominence of women scientists particularly from developing countries, and bridge the gender gap to innovation. WiB has also served as a platform to highlight the work of established female scientists in these fields. Several award-winning women resear...

  5. A comparative analysis of Indoor WiFi Positioning at a large building complex

    DEFF Research Database (Denmark)

    Mathisen, Andreas; Krogh, Søren; Stisen, Allan

    2016-01-01

    Indoor Positioning based on WiFi has received extensive focus from research communities, owing its promises of ubiquitous positioning indoors for a variety of applications. The majority of the existing research on WiFi positioning centers around the improvement of positioning accuracy. However...... are in daily use. The positioning methods covered utilizes received signal strength from existing WiFi infrastructure to ease deployment and maintenance. We identify meaningful key metrics which describe different aspects of the methods’ performance. Using these metrics, we furthermore report on experiences...

  6. LTE/Wi-Fi Coexistence in 5 GHz ISM Spectrum: Issues, Solutions and Perspectives

    DEFF Research Database (Denmark)

    Abinader, Fuad; A. de Sousa Jr., Vicente; Choudhurry, Sayantan

    2018-01-01

    solutions is the aggregation of ISM unlicensed spectrum to licensed bands, using wireless networks defined by IEEE and 3GPP. While Wi-Fi networks are aggregated to LTE small cells via LTE/WLAN Aggregation (LWA), in proposals like LTE-U and LAA-LTE, the LTE air interface itself is used for transmission...... on the unlicensed band. Wi-Fi technology is widespread and also operates in the 5 GHz ISM spectrum bands, which may bring performance issues due to the coexistence of both technologies in the same spectrum band. This work is dedicated to the study of coexistence between LTE and Wi-Fi access systems operating in 5...

  7. LTE, WiMAX and WLAN network design, optimization and performance analysis

    CERN Document Server

    Korowajczuk, Leonhard

    2011-01-01

    A technological overview of LTE and WiMAX LTE, WiMAX and WLAN Network Design, Optimization and Performance Analysis provides a practical guide to LTE and WiMAX technologies introducing various tools and concepts used within. In addition, topics such as traffic modelling of IP-centric networks, RF propagation, fading, mobility, and indoor coverage are explored; new techniques which increase throughput such as MIMO and AAS technology are highlighted; and simulation, network design and performance analysis are also examined. Finally, in the latter part of the book Korowajczuk gives a step-by-step

  8. Giant CP stars

    International Nuclear Information System (INIS)

    Loden, L.O.; Sundman, A.

    1989-01-01

    This study is part of an investigation of the possibility of using chemically peculiar (CP) stars to map local galactic structure. Correct luminosities of these stars are therefore crucial. CP stars are generally regarded as main-sequence or near-main-sequence objects. However, some CP stars have been classified as giants. A selection of stars, classified in literature as CP giants, are compared to normal stars in the same effective temperature interval and to ordinary 'non giant' CP stars. There is no clear confirmation of a higher luminosity for 'CP giants', than for CP stars in general. In addition, CP characteristics seem to be individual properties not repeated in a component star or other cluster members. (author). 50 refs., 5 tabs., 3 figs

  9. Towards the validation of SeaWiFS in Southern African Waters: The ...

    African Journals Online (AJOL)

    emission matrices, performed on filtered seawater samples. Modelled bio-optical data, using conditions typical of high biomass marine environments, are then used to assess the performance of a proposed SeaWiFS combined algorithm with ...

  10. Collaborative WiFi Fingerprinting Using Sensor-Based Navigation on Smartphones.

    Science.gov (United States)

    Zhang, Peng; Zhao, Qile; Li, You; Niu, Xiaoji; Zhuang, Yuan; Liu, Jingnan

    2015-07-20

    This paper presents a method that trains the WiFi fingerprint database using sensor-based navigation solutions. Since micro-electromechanical systems (MEMS) sensors provide only a short-term accuracy but suffer from the accuracy degradation with time, we restrict the time length of available indoor navigation trajectories, and conduct post-processing to improve the sensor-based navigation solution. Different middle-term navigation trajectories that move in and out of an indoor area are combined to make up the database. Furthermore, we evaluate the effect of WiFi database shifts on WiFi fingerprinting using the database generated by the proposed method. Results show that the fingerprinting errors will not increase linearly according to database (DB) errors in smartphone-based WiFi fingerprinting applications.

  11. SAFARI 2000 SeaWiFS Images for Core Study Sites, 2000-2001

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains Sea-viewing Wide Field-of-view Sensor (SeaWiFS) imagery for the eight core study sites of Mongu, Etosha, Kasangu, Skukuza, Mutoko, Mzola,...

  12. SAFARI 2000 SeaWiFS Images for Core Study Sites, 2000-2001

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set contains Sea-viewing Wide Field-of-view Sensor (SeaWiFS) imagery for the eight core study sites of Mongu, Etosha, Kasangu, Skukuza, Mutoko,...

  13. EnviroAtlas - Green Bay, WI - Meter-Scale Urban Land Cover (MULC) Data (2010)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Green Bay, WI Meter-Scale Urban Land Cover (MULC) dataset comprises 936 km2 around the city of Green Bay, surrounding towns, tribal lands and rural areas in...

  14. EnviroAtlas - Milwaukee, WI - Meter-Scale Urban Land Cover Data (MULC) Data (2010)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The EnviroAtlas Milwaukee, WI Meter Urban Land Cover (MULC) data and map were generated from USDA NAIP (National Agricultural Imagery Program) four band (red, green,...

  15. Energy production in stars

    International Nuclear Information System (INIS)

    Bethe, Hans.

    1977-01-01

    Energy in stars is released partly by gravitation, partly by nuclear reactions. For ordinary stars like our sun, nuclear reactions predominate. However, at the end of the life of a star very large amounts of energy are released by gravitational collapse; this can amount to as much as 10 times the total energy released nuclear reactions. The rotational energy of pulsars is a small remnant of the energy of gravitation. The end stage of small stars is generally a white dwarf, of heavy stars a neutron star of possibly a black hole

  16. Rates of star formation

    International Nuclear Information System (INIS)

    Larson, R.B.

    1977-01-01

    It is illustrated that a theoretical understanding of the formation and evolution of galaxies depends on an understanding of star formation, and especially of the factors influencing the rate of star formation. Some of the theoretical problems of star formation in galaxies, some approaches that have been considered in models of galaxy evolution, and some possible observational tests that may help to clarify which processes or models are most relevant are reviewed. The material is presented under the following headings: power-law models for star formation, star formation processes (conditions required, ways of achieving these conditions), observational indications and tests, and measures of star formation rates in galaxies. 49 references

  17. A new approach for indoor customer tracking based on a single Wi-Fi connection

    OpenAIRE

    Bai, Yuntian Brian; Wu, Suqin; Ren, Yongli; Ong, Kevin; Retscher, Guenther; Kealy, Allison; Tomko, Martin; Sanderson, Mark; Wu, Hongren; Zhang, Kefei

    2014-01-01

    Wi-Fi and smartphone based location tracking technologies have been widely applied in location based services (LBS). This research is a part of an Australian Research Council (ARC) project required by a large global shopping mall company located in Australia. It aims to develop an effective customer tracking approach for acquiring shopping behavior of customers and providing them better services. Currently, the log data provided by the company only recorded one Wi-Fi connection at a time for ...

  18. WiFi Data Acquisition System Applied to a Photovoltaic Powered Water Pumping Plant

    OpenAIRE

    Sandro César Silveira JUCÁ; Renata Imaculada Soares PEREIRA; Paulo Cesar Marques de CARVALHO

    2015-01-01

    The present paper describes how to design and assemble a low cost online monitoring and WiFi data acquisition system using free software applied to microgeneration based on renewable energy sources. The development of online monitoring systems for microgeneration plants based on renewable energy sources is becoming more important, considering that monitoring and data acquisition systems are applicable in stages of the microgeneration process. The monitoring and data acquisition WiFi system wa...

  19. Insecure Network, Unknown Connection: Understanding Wi-Fi Privacy Assumptions of Mobile Device Users

    OpenAIRE

    Bonné, Bram; Rovelo Ruiz, Gustavo; Quax, Peter; Lamotte, Wim

    2017-01-01

    Smartphones and other mobile devices have proliferated in the past five years. The expectation of mobile device users to always be online has led to Wi-Fi networks being offered by a variety of providers. Using these networks introduces multiple security risks. In this work, we assess to what extent the privacy stance of mobile device users corresponds with their actual behavior by conducting a study with 108 participants. Our methodology consists of monitoring Wi-Fi networks that the partici...

  20. Coexistence of ZigBee-Based WBAN and WiFi for Health Telemonitoring Systems.

    Science.gov (United States)

    Kim, Yena; Lee, SeungSeob; Lee, SuKyoung

    2016-01-01

    The development of telemonitoring via wireless body area networks (WBANs) is an evolving direction in personalized medicine and home-based mobile health. A WBAN consists of small, intelligent medical sensors which collect physiological parameters such as electrocardiogram, electroencephalography, and blood pressure. The recorded physiological signals are sent to a coordinator via wireless technologies, and are then transmitted to a healthcare monitoring center. One of the most widely used wireless technologies in WBANs is ZigBee because it is targeted at applications that require a low data rate and long battery life. However, ZigBee-based WBANs face severe interference problems in the presence of WiFi networks. This problem is caused by the fact that most ZigBee channels overlap with WiFi channels, severely affecting the ability of healthcare monitoring systems to guarantee reliable delivery of physiological signals. To solve this problem, we have developed an algorithm that controls the load in WiFi networks to guarantee the delay requirement for physiological signals, especially for emergency messages, in environments with coexistence of ZigBee-based WBAN and WiFi. Since WiFi applications generate traffic with different delay requirements, we focus only on WiFi traffic that does not have stringent timing requirements. In this paper, therefore, we propose an adaptive load control algorithm for ZigBee-based WBAN/WiFi coexistence environments, with the aim of guaranteeing that the delay experienced by ZigBee sensors does not exceed a maximally tolerable period of time. Simulation results show that our proposed algorithm guarantees the delay performance of ZigBee-based WBANs by mitigating the effects of WiFi interference in various scenarios.

  1. Analysis of MIMO Systems used in planning a 4G-WiMAX Network in Ghana

    OpenAIRE

    Tchao, E. T.; Diawuo, K.; Ofosu, W. K.; Affum, E.

    2013-01-01

    with the increasing demand for mobile data services, Broadband Wireless Access (BWA) is emerging as one of the fastest growing areas within mobile communications. Innovative wireless communication systems, such as WiMAX, are expected to offer highly reliable broadband radio access in order to meet the increasing demands of emerging high speed data and multimedia services. In Ghana, deployment of WiMAX technology has recently begun. Planning these high capacity networks in the presence of mult...

  2. Penentuan Arah Teleskop Digital Melalui Komunikasi Wi-Fi

    Directory of Open Access Journals (Sweden)

    Prima Kurniawan

    2013-09-01

    Full Text Available Teleskop bintang adalah sebuah perangkat instrument yang digunakan untuk melihat benda-benda langit yang jaraknya sangat jauh menjadi terasa dekat. Teleskop yang tersedia pada umumnya belum dilengkapi dengan sistem digital untuk pencitraannya dan otomatisasi untuk penentuan arahnya. Pada tugas akhir ini dibuat suatu sistem digital dan otomatisasi pada teleskop konvensional. Sistem digital digunakan untuk perekaman hasil yang didapatkan oleh teleskop dan ditampilakan pada komputer. Sistem otomatisasi dibuat untuk menentukan pergerakan sudut teleskop dengan sebuah GUI. Mekanik pergerakan teleskop diberikan 2 motor dc sebagai penggerak. Masing-masing motor dc berfungsi untuk menggerakkan tiap sumbu X dan sumbu Y. Digunakan sebuah sistem mikrokontroler menggunakan ATmega 32 sebagai pengolahan data. Fitur ADC mikrokontroler digunakan untuk mengubah data analog perubahan tegangan yang terjadi pada potensiometer menjadi perubahan data digital yang akan dikonversi menjadi nilai pergerakan perubahan sudut. Sistem ini ditambahkan sebuah router yang berfungsi sebagai akses poin untuk jalur pengiriman dan penerimaan data antara komputer dengan mikrokontroler. Ditambahkan sebuah wiznet yang mampu mengkonversi data dari komunikasi serial ke data protokol TCP/IP dan sebaliknya. Pengujian pergerakan sudut sumbu X dilakukan pada sudut 0, 45, 90, 135, 180, 255, 270, 315, dan 360 sedangkan pergerakan sumbu Y dilakukan pada sudut 0, 10, 20, 30, 40, 50, 60, 70, 80, dan 90. Hasil pengujian pada sumbu X dan Y didapatkan beberapa error pada titik-titik tertentu dengan tingkat kesalahan mencapai 3.8% untuk sumbu x dan 2.5% untuk sumbu y. Penentuan pergerakan sudut dilakukan melalui komputer dengan menggunakan komunikasi wi-fi.

  3. Wi-Fi location fingerprinting using an intelligent checkpoint sequence

    Science.gov (United States)

    Retscher, Günther; Hofer, Hannes

    2017-09-01

    For Wi-Fi positioning location fingerprinting is very common but has the disadvantage that it is very labour consuming for the establishment of a database (DB) with received signal strength (RSS) scans measured on a large number of known reference points (RPs). To overcome this drawback a novel approach is developed which uses a logical sequence of intelligent checkpoints (iCPs) instead of RPs distributed in a regular grid. The iCPs are the selected RPs which have to be passed along the way for navigation from a start point A to the destination B. They are twofold intelligent because of the fact that they depend on their meaningful selection and because of their logical sequence in their correct order. Thus, always the following iCP is known due to a vector graph allocation in the DB and only a small limited number of iCPs needs to be tested when matching the current RSS scans. This reduces the required processing time significantly. It is proven that the iCP approach achieves a higher success rate than conventional approaches. In average correct matching results of 90.0% were achieved using a joint DB including RSS scans of all employed smartphones. An even higher success rate is achieved if the same mobile device is used in both the training and positioning phase.

  4. PAPR mitigation algorithms for OFDM WiMAX link

    Science.gov (United States)

    Rashwan, Gasem; Kenshil, Salih; Matin, Mohammad

    2013-09-01

    OFDM has been adopted in many high systems due to its high data rates and to its robust performance in fading channel. OFDM distributes the data among number of carriers which are called subcarriers. The subcarriers must be orthogonal to prevent the carrier from interfering to each other. Features such overcoming ISI (inter-symbol interference) and the complexity of Designing both receiver and transmitter made it ideal technique for both wired and wireless communication as long as optical communications. However, OFDM suffers from a defect called Peak Average power ratio (PAPR). APARP is crucial drawback that limits the way that OFDM functions and reducing or mitigating this factor in wireless and optical environment will help overcome and enhance the OFDM date rate. PAPR is the main cause of inter-carrier interference and high out-of-band power, and consequently Bit error rate BER. We investigate some of the techniques that mitigate the effect of PAPR. These techniques are merged together to provide a better PAPR reduction with the existing techniques. In this paper, we are proposing a new reduction algorithm to minimize the effect of the PAPR. The results and simulation are done in Optisystem V-11 and Matlab environment. These approaches will be applied on WiMAX application and the performances between the different techniques are examined.

  5. Towards Optimal Buffer Size in Wi-Fi Networks

    KAUST Repository

    Showail, Ahmad J.

    2016-01-19

    Buffer sizing is an important network configuration parameter that impacts the quality of data traffic. Falling memory cost and the fallacy that ‘more is better’ lead to over provisioning network devices with large buffers. Over-buffering or the so called ‘bufferbloat’ phenomenon creates excessive end-to-end delay in today’s networks. On the other hand, under-buffering results in frequent packet loss and subsequent under-utilization of network resources. The buffer sizing problem has been studied extensively for wired networks. However, there is little work addressing the unique challenges of wireless environment. In this dissertation, we discuss buffer sizing challenges in wireless networks, classify the state-of-the-art solutions, and propose two novel buffer sizing schemes. The first scheme targets buffer sizing in wireless multi-hop networks where the radio spectral resource is shared among a set of con- tending nodes. Hence, it sizes the buffer collectively and distributes it over a set of interfering devices. The second buffer sizing scheme is designed to cope up with recent Wi-Fi enhancements. It adapts the buffer size based on measured link characteristics and network load. Also, it enforces limits on the buffer size to maximize frame aggregation benefits. Both mechanisms are evaluated using simulation as well as testbed implementation over half-duplex and full-duplex wireless networks. Experimental evaluation shows that our proposal reduces latency by an order of magnitude.

  6. Regular Generalized Star Star closed sets in Bitopological Spaces

    OpenAIRE

    K. Kannan; D. Narasimhan; K. Chandrasekhara Rao; R. Ravikumar

    2011-01-01

    The aim of this paper is to introduce the concepts of τ1τ2-regular generalized star star closed sets , τ1τ2-regular generalized star star open sets and study their basic properties in bitopological spaces.

  7. Ubiquity of Wi-Fi: Crowdsensing Properties for Urban Fingerprint Positioning

    Directory of Open Access Journals (Sweden)

    LECA, C. L.

    2017-11-01

    Full Text Available Positioning systems based on location fingerprinting have become an area of intense research, mainly with the aim of providing indoor localization. Many challenges arise when trying to deploy location fingerprinting to an outdoor environment. The main problem is achieving coverage of large outdoor spaces, which needs an intensive data gathering effort. This paper proposes the use of mobile crowdsensing in order to build a fingerprint database consisting of Wi-Fi networks received signal strength measurements. Mobile crowdsensing is represented by the usage of smart-phones equipped with GPS and Wi-Fi sensors for the collection of fingerprints. The primary objective of this work is to prove the feasibility of urban positioning using Wi-Fi crowdsensed data by showing that Wi-Fi networks are ubiquitous in urban areas. We then examine the gathered data and report our findings on challenges in building and maintaining a large-scale fingerprint database, the influence of the data collection method on the Wi-Fi data and the influence of fading on measurements. As Wi-Fi access-points are shown to exhibit mobility, we also propose and analyze methods for detecting and classification of mobile and static access-points.

  8. An Improved Neural Network Training Algorithm for Wi-Fi Fingerprinting Positioning

    Directory of Open Access Journals (Sweden)

    Esmond Mok

    2013-09-01

    Full Text Available Ubiquitous positioning provides continuous positional information in both indoor and outdoor environments for a wide spectrum of location based service (LBS applications. With the rapid development of the low-cost and high speed data communication, Wi-Fi networks in many metropolitan cities, strength of signals propagated from the Wi-Fi access points (APs namely received signal strength (RSS have been cleverly adopted for indoor positioning. In this paper, a Wi-Fi positioning algorithm based on neural network modeling of Wi-Fi signal patterns is proposed. This algorithm is based on the correlation between the initial parameter setting for neural network training and output of the mean square error to obtain better modeling of the nonlinear highly complex Wi-Fi signal power propagation surface. The test results show that this neural network based data processing algorithm can significantly improve the neural network training surface to achieve the highest possible accuracy of the Wi-Fi fingerprinting positioning method.

  9. Influence of smartphone Wi-Fi signals on adipose-derived stem cells.

    Science.gov (United States)

    Lee, Sang-Soon; Kim, Hyung-Rok; Kim, Min-Sook; Park, Sanghoon; Yoon, Eul-Sik; Park, Seung-Ha; Kim, Deok-Woo

    2014-09-01

    The use of smartphones is expanding rapidly around the world, thus raising the concern of possible harmful effects of radiofrequency generated by smartphones. We hypothesized that Wi-Fi signals from smartphones may have harmful influence on adipose-derived stem cells (ASCs). An in vitro study was performed to assess the influence of Wi-Fi signals from smartphones. The ASCs were incubated under a smartphone connected to a Wi-Fi network, which was uploading files at a speed of 4.8 Mbps for 10 hours a day, for a total of 5 days. We constructed 2 kinds of control cells, one grown in 37°C and the other grown in 39°C. After 5 days of Wi-Fi exposure from the smartphone, the cells underwent cell proliferation assay, apoptosis assay, and flow cytometry analysis. Three growth factors, vascular endothelial growth factor, hepatocyte growth factor, and transforming growth factor-β, were measured from ASC-conditioned media. Cell proliferation rate was higher in Wi-Fi-exposed cells and 39°C control cells compared with 37°C control cells. Apoptosis assay, flow cytometry analysis, and growth factor concentrations showed no remarkable differences among the 3 groups. We could not find any harmful effects of Wi-Fi electromagnetic signals from smartphones. The increased proliferation of ASCs under the smartphone, however, might be attributable to the thermal effect.

  10. Continuous Indoor Positioning Fusing WiFi, Smartphone Sensors and Landmarks

    Directory of Open Access Journals (Sweden)

    Zhi-An Deng

    2016-09-01

    Full Text Available To exploit the complementary strengths of WiFi positioning, pedestrian dead reckoning (PDR, and landmarks, we propose a novel fusion approach based on an extended Kalman filter (EKF. For WiFi positioning, unlike previous fusion approaches setting measurement noise parameters empirically, we deploy a kernel density estimation-based model to adaptively measure the related measurement noise statistics. Furthermore, a trusted area of WiFi positioning defined by fusion results of previous step and WiFi signal outlier detection are exploited to reduce computational cost and improve WiFi positioning accuracy. For PDR, we integrate a gyroscope, an accelerometer, and a magnetometer to determine the user heading based on another EKF model. To reduce accumulation error of PDR and enable continuous indoor positioning, not only the positioning results but also the heading estimations are recalibrated by indoor landmarks. Experimental results in a realistic indoor environment show that the proposed fusion approach achieves substantial positioning accuracy improvement than individual positioning approaches including PDR and WiFi positioning.

  11. Continuous Indoor Positioning Fusing WiFi, Smartphone Sensors and Landmarks.

    Science.gov (United States)

    Deng, Zhi-An; Wang, Guofeng; Qin, Danyang; Na, Zhenyu; Cui, Yang; Chen, Juan

    2016-09-05

    To exploit the complementary strengths of WiFi positioning, pedestrian dead reckoning (PDR), and landmarks, we propose a novel fusion approach based on an extended Kalman filter (EKF). For WiFi positioning, unlike previous fusion approaches setting measurement noise parameters empirically, we deploy a kernel density estimation-based model to adaptively measure the related measurement noise statistics. Furthermore, a trusted area of WiFi positioning defined by fusion results of previous step and WiFi signal outlier detection are exploited to reduce computational cost and improve WiFi positioning accuracy. For PDR, we integrate a gyroscope, an accelerometer, and a magnetometer to determine the user heading based on another EKF model. To reduce accumulation error of PDR and enable continuous indoor positioning, not only the positioning results but also the heading estimations are recalibrated by indoor landmarks. Experimental results in a realistic indoor environment show that the proposed fusion approach achieves substantial positioning accuracy improvement than individual positioning approaches including PDR and WiFi positioning.

  12. Quark core stars, quark stars and strange stars

    International Nuclear Information System (INIS)

    Grassi, F.

    1988-01-01

    A recent one flavor quark matter equation of state is generalized to several flavors. It is shown that quarks undergo a first order phase transition. In addition, this equation of state depends on just one parameter in the two flavor case, two parameters in the three flavor case, and these parameters are constrained by phenomenology. This equation of state is then applied to the hadron-quark transition in neutron stars and the determination of quark star stability, the investigation of strange matter stability and possible strange star existence. 43 refs., 6 figs

  13. Calibration of SeaWiFS after two years on orbit

    Science.gov (United States)

    Barnes, Robert A.; McClain, Charles R.

    1999-12-01

    The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) was launched on 1 August 1997, and the first Earth images were taken on 4 September 1997. Regular, daily measurements of the sun, via the onboard diffuser, started on 9 September 1997 and regular, monthly measurements of the moon on November 14, 1997. These lunar measurements, as first reported at EUROPTO'98, provide a highly sensitive method for determining the change in the radiometric sensitivity of SeaWiFS. The prelaunch radiometric calibration used by SeaWiFS was performed in the Spring of 1997 at the spacecraft manufacturer's facility. The calibration measurements were made by a team from the National Institute of Standards and Technology (NIST) and the SeaWiFS Project. The uncertainties in this calibration range from 2% to 3% for the eight SeaWiFS bands. In addition, a set of outdoor measurements of the sun were made at the instrument manufacturer's facility in November 1993, just before the delivery of SeaWiFS to the spacecraft manufacturer. These solar measurements, using the instrument's diffuser, were combined with a separate set of solar radiometer measurements to determine the transmittance of the atmosphere. At the start of on-orbit measurements by SeaWiFS, solar measurements were made again by the instrument. These two sets of measurements make up the transfer-to-orbit experiment. From the ground measurements, the outputs of the SeaWiFS bands on orbit were predicted. For each band, the output from the initial on-orbit measurements agree with the predicted values by 21/2% or less. The uncertainties for the transfer-to-orbit experiment are estimated to be approximately 3% to 4%. From 14 November 1997 to 29 June 1999, SeaWiFS has made 20 measurements of the moon. The analysis of lunar measurements presented here has minor modifications to that presented at EUROPTO'98. The trend lines from the current analysis have been extrapolated back from 14 November 1997 to 4 September 1997 to describe the changes

  14. Validation of SeaWiFS and MODIS Aqua/Terra aerosol products in coastal regions of European marginal seas

    Directory of Open Access Journals (Sweden)

    Frédéric Mélin

    2013-02-01

    Full Text Available The aerosol products associated with the ocean colour missions SeaWiFS andMODIS (both Aqua and Terra are assessed with AERONET field measurementscollected in four European marginal seas for which fairly large uncertainties inocean colour in-water products have been documented: the northern Adriatic, theBaltic, Black and North Seas. On average, more than 500 match-ups are foundfor each basin and satellite mission, showing an overall consistency of validationstatistics across the three missions. The median absolute relative differencebetween satellite and field values of aerosol optical thickness τaat 443 nm varies from 12% to 15% for the three missions at the northernAdriatic and Black Sea sites, and from 13% to 26% for the Baltic and North Sea sites. It is in the interval 16-31% for the near-infrared band. The spectral shape of τaiswell reproduced with a median bias of the Ängström exponent varyingbetween -15% and +14%, which represents a clear improvement with respectto previous versions of the atmospheric correction scheme. These results showthat the uncertainty associated with τa in the considered coastalwaters of the European marginal seas is comparable to global validationstatistics

  15. ENERGY STAR Certified Televisions

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 7.0 ENERGY STAR Program Requirements for Televisions that are effective as of October 30,...

  16. mSTAR

    Data.gov (United States)

    National Aeronautics and Space Administration — Mini-STAR (mSTAR) is a small satellite mission concept to test the hypothesis that the velocity of light is independent of the velocity and orientation of the...

  17. ENERGY STAR Certified Boilers

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 3.0 ENERGY STAR Program Requirements for Boilers that are effective as of October 1,...

  18. Observations of central stars

    International Nuclear Information System (INIS)

    Lutz, J.H.

    1978-01-01

    Difficulties occurring in the observation of central stars of planetary nebulae are reviewed with emphasis on spectral classifications and population types, and temperature determination. Binary and peculiar central stars are discussed. (U.M.G.)

  19. ENERGY STAR Certified Computers

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 6.1 ENERGY STAR Program Requirements for Computers that are effective as of June 2, 2014....

  20. ENERGY STAR Certified Furnaces

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 4.1 ENERGY STAR Program Requirements for Furnaces that are effective as of February 1,...

  1. ENERGY STAR Certified Telephones

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 3.0 ENERGY STAR Program Requirements for Telephony (cordless telephones and VoIP...

  2. ENERGY STAR Certified Dehumidifiers

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 4.0 ENERGY STAR Program Requirements for Dehumidifiers that are effective as of October...

  3. Autonomous Star Tracker Algorithms

    DEFF Research Database (Denmark)

    Betto, Maurizio; Jørgensen, John Leif; Kilsgaard, Søren

    1998-01-01

    Proposal, in response to an ESA R.f.P., to design algorithms for autonomous star tracker operations.The proposal also included the development of a star tracker breadboard to test the algorithms performances.......Proposal, in response to an ESA R.f.P., to design algorithms for autonomous star tracker operations.The proposal also included the development of a star tracker breadboard to test the algorithms performances....

  4. America's Star Libraries

    Science.gov (United States)

    Lyons, Ray; Lance, Keith Curry

    2009-01-01

    "Library Journal"'s new national rating of public libraries, the "LJ" Index of Public Library Service, identifies 256 "star" libraries. It rates 7,115 public libraries. The top libraries in each group get five, four, or three Michelin guide-like stars. All included libraries, stars or not, can use their scores to learn from their peers and improve…

  5. Rotating Stars in Relativity

    Directory of Open Access Journals (Sweden)

    Stergioulas Nikolaos

    2003-01-01

    Full Text Available Rotating relativistic stars have been studied extensively in recent years, both theoretically and observationally, because of the information they might yield about the equation of state of matter at extremely high densities and because they are considered to be promising sources of gravitational waves. The latest theoretical understanding of rotating stars in relativity is reviewed in this updated article. The sections on the equilibrium properties and on the nonaxisymmetric instabilities in f-modes and r-modes have been updated and several new sections have been added on analytic solutions for the exterior spacetime, rotating stars in LMXBs, rotating strange stars, and on rotating stars in numerical relativity.

  6. Magnetism of hot stars

    Science.gov (United States)

    Wade, G. A.; Neiner, C.

    2018-01-01

    Strong, stable, and organised magnetic fields are present at the surfaces of a small fraction of OBA stars. These "fossil fields" exhibit uniform characteristics in stars over a tremendous range of stellar mass, age, temperature, and rotation rate. In hot O- and B-type stars, these magnetic fields couple efficiently to the stellar radiatively driven winds, strongly influencing stellar mass loss and rotation. In this article we review the characteristics of the known magnetic hot stars, discuss recent discoveries and insights, and describe recent theoretical progress toward understanding basic field properties and the influence of magnetic fields on hot star evolution.

  7. Nuclear physics of stars

    CERN Document Server

    Iliadis, Christian

    2015-01-01

    Most elements are synthesized, or ""cooked"", by thermonuclear reactions in stars. The newly formed elements are released into the interstellar medium during a star's lifetime, and are subsequently incorporated into a new generation of stars, into the planets that form around the stars, and into the life forms that originate on the planets. Moreover, the energy we depend on for life originates from nuclear reactions that occur at the center of the Sun. Synthesis of the elements and nuclear energy production in stars are the topics of nuclear astrophysics, which is the subject of this book

  8. THE FIRST STARS

    Directory of Open Access Journals (Sweden)

    Daniel J. Whalen

    2013-12-01

    Full Text Available Pop III stars are the key to the character of primeval galaxies, the first heavy elements, the onset of cosmological reionization, and the seeds of supermassive black holes. Unfortunately, in spite of their increasing sophistication, numerical models of Pop III star formation cannot yet predict the masses of the first stars. Because they also lie at the edge of the observable universe, individual Pop III stars will remain beyond the reach of observatories for decades to come, and so their properties are unknown. However, it will soon be possible to constrain their masses by direct detection of their supernovae, and by reconciling their nucleosynthetic yields to the chemical abundances measured in ancient metal-poor stars in the Galactic halo, some of which may bear the ashes of the first stars. Here, I review the state of the art in numerical simulations of primordial stars and attempts to directly and indirectly constrain their properties.

  9. Ponderable soliton stars

    Science.gov (United States)

    Chiu, Hong-Yee

    1990-01-01

    The theory of Lee and Pang (1987), who obtained solutions for soliton stars composed of zero-temperature fermions and bosons, is applied here to quark soliton stars. Model soliton stars based on a simple physical model of the proton are computed, and the properties of the solitons are discussed, including the important problem of the existence of a limiting mass and thus the possible formation of black holes of primordial origin. It is shown that there is a definite mass limit for ponderable soliton stars, so that during cooling a soliton star might reach a stage beyond which no equilibrium configuration exists and the soliton star probably will collapse to become a black hole. The radiation of ponderable soliton stars may alter the short-wavelength character of the cosmic background radiation, and may be observed as highly redshifted objects at z of about 100,000.

  10. Effects of repeated restraint stress and WiFi signal exposure on behavior and oxidative stress in rats.

    Science.gov (United States)

    Othman, Haifa; Ammari, Mohamed; Sakly, Mohsen; Abdelmelek, Hafedh

    2017-10-01

    Today, due to technology development and aversive events of daily life, Human exposure to both radiofrequency and stress is unavoidable. This study investigated the co-exposure to repeated restraint stress and WiFi signal on cognitive function and oxidative stress in brain of male rats. Animals were divided into four groups: Control, WiFi-exposed, restrained and both WiFi-exposed and restrained groups. Each of WiFi exposure and restraint stress occurred 2 h (h)/day during 20 days. Subsequently, various tests were carried out for each group, such as anxiety in elevated plus maze, spatial learning abilities in the water maze, cerebral oxidative stress response and cholinesterase activity in brain and serum. Results showed that WiFi exposure and restraint stress, alone and especially if combined, induced an anxiety-like behavior without impairing spatial learning and memory abilities in rats. At cerebral level, we found an oxidative stress response triggered by WiFi and restraint, per se and especially when combined as well as WiFi-induced increase in acetylcholinesterase activity. Our results reveal that there is an impact of WiFi signal and restraint stress on the brain and cognitive processes especially in elevated plus maze task. In contrast, there are no synergistic effects between WiFi signal and restraint stress on the brain.

  11. The Architecture of WiFi-Based WSN for AMR System and E-HWMP Routing Protocol

    Directory of Open Access Journals (Sweden)

    Li LI

    2014-02-01

    Full Text Available With the development of SoC technology in recent years, the ultra-low power WiFi System on SoC Chip has emerged. As a result, WiFi-based Wireless Sensor Networks come into use, especially used in Automatic Meter Reading. While because the nodes of Wireless Sensor Networks have limited energy supply, smaller storage capability and slower calculation ability, the current WiFi technology cannot be directly applied to WiFi-based Wireless Sensor Networks. The protocols should be upgraded and the security algorithms should be improved to meet the new requests. Firstly, this article describes the network architecture of WiFi-based WSN for AMR system and discusses the reason for using this analogous Mesh architecture. Secondly, the new Hardware architecture of WiFi-based WSN node is designed to realize the AMR system and verify the research work. The node can collect the data of power meter by WiFi and can be powered by a Lithium Battery. Thirdly, on the basis of study work of WiFi original routing protocol HWMP, a new method on improving the energy saving ability of HWMP to adapt the new features of WiFi-based WSN is proposed. And the simulation work on the new routing protocol E-HWMP has been done with NS2 and the simulation results show that the life cycle of the network has been extended to some degree.

  12. Advanced Integration of WiFi and Inertial Navigation Systems for Indoor Mobile Positioning

    Directory of Open Access Journals (Sweden)

    Evennou Frédéric

    2006-01-01

    Full Text Available This paper presents an aided dead-reckoning navigation structure and signal processing algorithms for self localization of an autonomous mobile device by fusing pedestrian dead reckoning and WiFi signal strength measurements. WiFi and inertial navigation systems (INS are used for positioning and attitude determination in a wide range of applications. Over the last few years, a number of low-cost inertial sensors have become available. Although they exhibit large errors, WiFi measurements can be used to correct the drift weakening the navigation based on this technology. On the other hand, INS sensors can interact with the WiFi positioning system as they provide high-accuracy real-time navigation. A structure based on a Kalman filter and a particle filter is proposed. It fuses the heterogeneous information coming from those two independent technologies. Finally, the benefits of the proposed architecture are evaluated and compared with the pure WiFi and INS positioning systems.

  13. Wi-Fi and health: review of current status of research.

    Science.gov (United States)

    Foster, Kenneth R; Moulder, John E

    2013-12-01

    This review summarizes the current state of research on possible health effects of Wi-Fi (a commercial name for IEEE 802.11-compliant wireless networking). In response to public concerns about health effects of Wi-Fi and wireless networks and calls by government agencies for research on possible health and safety issues with the technology, a considerable amount of technology-specific research has been completed. A series of high quality engineering studies have provided a good, but not complete, understanding of the levels of radiofrequency (RF) exposure to individuals from Wi-Fi. The limited number of technology-specific bioeffects studies done to date are very mixed in terms of quality and outcome. Unequivocally, the RF exposures from Wi-Fi and wireless networks are far below U.S. and international exposure limits for RF energy. While several studies report biological effects due to Wi-Fi-type exposures, technical limitations prevent drawing conclusions from them about possible health risks of the technology. The review concludes with suggestions for future research on the topic.

  14. Indoor Map Aided Wi-Fi Integrated Lbs on Smartphone Platforms

    Science.gov (United States)

    Yu, C.; El-Sheimy, N.

    2017-09-01

    In this research, an indoor map aided INS/Wi-Fi integrated location based services (LBS) applications is proposed and implemented on smartphone platforms. Indoor map information together with measurements from an inertial measurement unit (IMU) and Received Signal Strength Indicator (RSSI) value from Wi-Fi are collected to obtain an accurate, continuous, and low-cost position solution. The main challenge of this research is to make effective use of various measurements that complement each other without increasing the computational burden of the system. The integrated system in this paper includes three modules: INS, Wi-Fi (if signal available) and indoor maps. A cascade structure Particle/Kalman filter framework is applied to combine the different modules. Firstly, INS position and Wi-Fi fingerprint position integrated through Kalman filter for estimating positioning information. Then, indoor map information is applied to correct the error of INS/Wi-Fi estimated position through particle filter. Indoor tests show that the proposed method can effectively reduce the accumulation positioning errors of stand-alone INS systems, and provide stable, continuous and reliable indoor location service.

  15. An Improved WiFi Indoor Positioning Algorithm by Weighted Fusion.

    Science.gov (United States)

    Ma, Rui; Guo, Qiang; Hu, Changzhen; Xue, Jingfeng

    2015-08-31

    The rapid development of mobile Internet has offered the opportunity for WiFi indoor positioning to come under the spotlight due to its low cost. However, nowadays the accuracy of WiFi indoor positioning cannot meet the demands of practical applications. To solve this problem, this paper proposes an improved WiFi indoor positioning algorithm by weighted fusion. The proposed algorithm is based on traditional location fingerprinting algorithms and consists of two stages: the offline acquisition and the online positioning. The offline acquisition process selects optimal parameters to complete the signal acquisition, and it forms a database of fingerprints by error classification and handling. To further improve the accuracy of positioning, the online positioning process first uses a pre-match method to select the candidate fingerprints to shorten the positioning time. After that, it uses the improved Euclidean distance and the improved joint probability to calculate two intermediate results, and further calculates the final result from these two intermediate results by weighted fusion. The improved Euclidean distance introduces the standard deviation of WiFi signal strength to smooth the WiFi signal fluctuation and the improved joint probability introduces the logarithmic calculation to reduce the difference between probability values. Comparing the proposed algorithm, the Euclidean distance based WKNN algorithm and the joint probability algorithm, the experimental results indicate that the proposed algorithm has higher positioning accuracy.

  16. Advanced Integration of WiFi and Inertial Navigation Systems for Indoor Mobile Positioning

    Science.gov (United States)

    Evennou, Frédéric; Marx, François

    2006-12-01

    This paper presents an aided dead-reckoning navigation structure and signal processing algorithms for self localization of an autonomous mobile device by fusing pedestrian dead reckoning and WiFi signal strength measurements. WiFi and inertial navigation systems (INS) are used for positioning and attitude determination in a wide range of applications. Over the last few years, a number of low-cost inertial sensors have become available. Although they exhibit large errors, WiFi measurements can be used to correct the drift weakening the navigation based on this technology. On the other hand, INS sensors can interact with the WiFi positioning system as they provide high-accuracy real-time navigation. A structure based on a Kalman filter and a particle filter is proposed. It fuses the heterogeneous information coming from those two independent technologies. Finally, the benefits of the proposed architecture are evaluated and compared with the pure WiFi and INS positioning systems.

  17. Star-Branched Polymers (Star Polymers)

    KAUST Repository

    Hirao, Akira

    2015-09-01

    The synthesis of well-defined regular and asymmetric mixed arm (hereinafter miktoarm) star-branched polymers by the living anionic polymerization is reviewed in this chapter. In particular, much attention is being devoted to the synthetic development of miktoarm star polymers since 2000. At the present time, the almost all types of multiarmed and multicomponent miktoarm star polymers have become feasible by using recently developed iterative strategy. For example, the following well-defined stars have been successfully synthesized: 3-arm ABC, 4-arm ABCD, 5-arm ABCDE, 6-arm ABCDEF, 7-arm ABCDEFG, 6-arm ABC, 9-arm ABC, 12-arm ABC, 13-arm ABCD, 9-arm AB, 17-arm AB, 33-arm AB, 7-arm ABC, 15-arm ABCD, and 31-arm ABCDE miktoarm star polymers, most of which are quite new and difficult to synthesize by the end of the 1990s. Several new specialty functional star polymers composed of vinyl polymer segments and rigid rodlike poly(acetylene) arms, helical polypeptide, or helical poly(hexyl isocyanate) arms are introduced.

  18. Dark stars: a review.

    Science.gov (United States)

    Freese, Katherine; Rindler-Daller, Tanja; Spolyar, Douglas; Valluri, Monica

    2016-06-01

    Dark stars are stellar objects made (almost entirely) of hydrogen and helium, but powered by the heat from dark matter annihilation, rather than by fusion. They are in hydrostatic and thermal equilibrium, but with an unusual power source. Weakly interacting massive particles (WIMPs), among the best candidates for dark matter, can be their own antimatter and can annihilate inside the star, thereby providing a heat source. Although dark matter constitutes only [Formula: see text]0.1% of the stellar mass, this amount is sufficient to power the star for millions to billions of years. Thus, the first phase of stellar evolution in the history of the Universe may have been dark stars. We review how dark stars come into existence, how they grow as long as dark matter fuel persists, and their stellar structure and evolution. The studies were done in two different ways, first assuming polytropic interiors and more recently using the MESA stellar evolution code; the basic results are the same. Dark stars are giant, puffy (∼10 AU) and cool (surface temperatures  ∼10 000 K) objects. We follow the evolution of dark stars from their inception at  ∼[Formula: see text] as they accrete mass from their surroundings to become supermassive stars, some even reaching masses  >[Formula: see text] and luminosities  >[Formula: see text], making them detectable with the upcoming James Webb Space Telescope. Once the dark matter runs out and the dark star dies, it may collapse to a black hole; thus dark stars may provide seeds for the supermassive black holes observed throughout the Universe and at early times. Other sites for dark star formation may exist in the Universe today in regions of high dark matter density such as the centers of galaxies. The current review briefly discusses dark stars existing today, but focuses on the early generation of dark stars.

  19. QoS Management and Control for an All-IP WiMAX Network Architecture: Design, Implementation and Evaluation

    Directory of Open Access Journals (Sweden)

    Thomas Michael Bohnert

    2008-01-01

    Full Text Available The IEEE 802.16 standard provides a specification for a fixed and mobile broadband wireless access system, offering high data rate transmission of multimedia services with different Quality-of-Service (QoS requirements through the air interface. The WiMAX Forum, going beyond the air interface, defined an end-to-end WiMAX network architecture, based on an all-IP platform in order to complete the standards required for a commercial rollout of WiMAX as broadband wireless access solution. As the WiMAX network architecture is only a functional specification, this paper focuses on an innovative solution for an end-to-end WiMAX network architecture offering in compliance with the WiMAX Forum specification. To our best knowledge, this is the first WiMAX architecture built by a research consortium globally and was performed within the framework of the European IST project WEIRD (WiMAX Extension to Isolated Research Data networks. One of the principal features of our architecture is support for end-to-end QoS achieved by the integration of resource control in the WiMAX wireless link and the resource management in the wired domains in the network core. In this paper we present the architectural design of these QoS features in the overall WiMAX all-IP framework and their functional as well as performance evaluation. The presented results can safely be considered as unique and timely for any WiMAX system integrator.

  20. Comparative Performance Evaluation of TCP Variants in WiMAX (and WLANs Network Configurations

    Directory of Open Access Journals (Sweden)

    Konstantinos Tsiknas

    2012-01-01

    Full Text Available An important application for the IEEE 802.16 technology (also called WiMAX is to provide high-speed access to the Internet where the transmission control protocol (TCP is the core transport protocol. In this paper we study through extensive simulation scenarios the performance characteristics of five representative TCP schemes, namely, TCP New Reno, Vegas, Veno, Westwood, and BIC, in WiMAX (and WLANs networks, under the conditions of correlated wireless errors, asymmetric end-to-end capabilities, and link congestion. The target is to evaluate how the above conditions would affect the TCP congestion control and suggest the best schemes to be employed in WiMAX networks.

  1. QoS Provisioning Techniques for Future Fiber-Wireless (FiWi Access Networks

    Directory of Open Access Journals (Sweden)

    Martin Maier

    2010-04-01

    Full Text Available A plethora of enabling optical and wireless access-metro network technologies have been emerging that can be used to build future-proof bimodal fiber-wireless (FiWi networks. Hybrid FiWi networks aim at providing wired and wireless quad-play services over the same infrastructure simultaneously and hold great promise to mitigate the digital divide and change the way we live and work by replacing commuting with teleworking. After overviewing enabling optical and wireless network technologies and their QoS provisioning techniques, we elaborate on enabling radio-over-fiber (RoF and radio-and-fiber (R&F technologies. We describe and investigate new QoS provisioning techniques for future FiWi networks, ranging from traffic class mapping, scheduling, and resource management to advanced aggregation techniques, congestion control, and layer-2 path selection algorithms.

  2. Spectrum Sensing Experimentation for LTE and WiFi Unlicensed Band Operation

    Directory of Open Access Journals (Sweden)

    N. Milošević

    2016-11-01

    Full Text Available If several different systems operate in the same frequency band, a coordination between them is needed for effective use of the available spectrum. The coordination is especially important if the systems are not designed to operate in such an environment. The very important initial phase of the coordination process is acquiring of the spectrum usage map or spectrum sensing. The paper describes the spectrum sensing experimentation in the unlicensed 5 GHz band during the WiFi or LTE transmission. It describes the experiment workflow and depicts the obtained results. The experiments were performed at NITOS testbed at the University of Thessaly, Greece, and show that it is possible to determine whether WiFi or LTE transmission is sensed. Therefore, based on spectrum sensing it will be possible to coordinate a shared access of WiFi and LTE users in the unlicensed 5 GHz band.

  3. Experimental verification of a radiofrequency power model for Wi-Fi technology.

    Science.gov (United States)

    Fang, Minyu; Malone, David

    2010-04-01

    When assessing the power emitted from a Wi-Fi network, it has been observed that these networks operate at a relatively low duty cycle. In this paper, we extend a recently introduced model of emitted power in Wi-Fi networks to cover conditions where devices do not always have packets to transmit. We present experimental results to validate the original model and its extension by developing approximate, but practical, testbed measurement techniques. The accuracy of the models is confirmed, with small relative errors: less than 5-10%. Moreover, we confirm that the greatest power is emitted when the network is saturated with traffic. Using this, we give a simple technique to quickly estimate power output based on traffic levels and give examples showing how this might be used in practice to predict current or future power output from a Wi-Fi network.

  4. Seeing Stars in Serpens

    Science.gov (United States)

    2006-01-01

    Infant stars are glowing gloriously in this infrared image of the Serpens star-forming region, captured by NASA's Spitzer Space Telescope. The reddish-pink dots are baby stars deeply embedded in the cosmic cloud of gas and dust that collapsed to create it. A dusty disk of cosmic debris, or 'protoplanetary disk,' that may eventually form planets, surrounds the infant stars. Wisps of green throughout the image indicate the presence of carbon rich molecules called polycyclic aromatic hydrocarbons. On Earth, these molecules can be found on charred barbecue grills and in automobile exhaust. Blue specks sprinkled throughout the image are background stars in our Milky Way galaxy. The Serpens star-forming region is located approximately 848 light-years away in the Serpens constellation. The image is a three-channel, false-color composite, where emission at 4.5 microns is blue, emission at 8.0 microns is green, and 24 micron emission is red.

  5. Slowly pulsating B stars

    Science.gov (United States)

    Waelkens, C.

    1991-06-01

    Photometric data obtained during several years of observations of seven B-type stars are analyzed, including HD 74195 (Omicron Velorum), HD 74560 (HD 3467), HD 123515 (HR 5296), HD 143309, HD 160124, HD 177863 (HR 7241), and HD 181558 (HR 7339). Results indicate that all seven stars are multiperiodic variables with periods of the order of days. Two periods were identified for HD 177863, three periods for HD 74560 and HD 181558, four periods for HD 123515, five periods for HD 74195, six periods for HD 143309, and eight periods for HD 160124. The multiperiodicity and the amplitude behavior of these stars point toward pulsation in high-radial-order g-modes in the stars. It is suggested that these stars form a distinct group of early-type variables, which are named here 'slowly pulsating B stars'.

  6. Effect of radiofrequency radiation from Wi-Fi devices on mercury release from amalgam restorations.

    Science.gov (United States)

    Paknahad, Maryam; Mortazavi, S M J; Shahidi, Shoaleh; Mortazavi, Ghazal; Haghani, Masoud

    2016-01-01

    Dental amalgam is composed of approximately 50% elemental mercury. Despite concerns over the toxicity of mercury, amalgam is still the most widely used restorative material. Wi-Fi is a rapidly using local area wireless computer networking technology. To the best of our knowledge, this is the first study that evaluates the effect of exposure to Wi-Fi signals on mercury release from amalgam restorations. Standard class V cavities were prepared on the buccal surfaces of 20 non-carious extracted human premolars. The teeth were randomly divided into 2 groups (n = 10). The control group was stored in non-environment. The specimens in the experimental groups were exposed to a radiofrequency radiation emitted from standard Wi Fi devices at 2.4 GHz for 20 min. The distance between the Wi-Fi router and samples was 30 cm and the router was exchanging data with a laptop computer that was placed 20 m away from the router. The concentration of mercury in the artificial saliva in the groups was evaluated by using a cold-vapor atomic absorption Mercury Analyzer System. The independent t test was used to evaluate any significant differences in mercury release between the two groups. The mean (±SD) concentration of mercury in the artificial saliva of the Wi-Fi exposed teeth samples was 0.056 ± .025 mg/L, while it was only 0.026 ± .008 mg/L in the non-exposed control samples. This difference was statistically significant (P =0.009). Exposure of patients with amalgam restorations to radiofrequency radiation emitted from conventional Wi-Fi devices can increase mercury release from amalgam restorations.

  7. To promote public acceptance of nuclear energy by WiN-JAPAN

    International Nuclear Information System (INIS)

    Kuroiwa, Haruko; Kobayashi, Yoko; Ogawa, Junko

    2011-01-01

    Women in Nuclear Japan (WiN-J) has been striving to promote activities that increase public acceptance of nuclear energy especially by women. According to a public opinion poll in 2009 by the Cabient Office, Government of Japan, the ratio of men who have confidence in nuclear power plant safety was 52.1%, while the ratio of females was only 32.5%. And the ratio of negative feeling about nuclear power among males was 45.8%, while the ratio of females was 61.2%. This indicates the necessity of communication to females to encourage them to accept nuclear power. WiN-J developed two methods of communication with the public and young people about the benefits of nuclear energy and the applications of radiation in many aspects of the life. The first is town hall meetings, and the other is education for university students in the style of a Science Cafe. Surprisingly, present university student never studied about nuclear energy when they were elementary or junior high school students. However, those students will have to educate their own children to use energy wisely in consideration of the limited energy resources in the coming years. WiN-J, therefore, gives them some relevant lectures on nuclear energy and radiation. Also WiN-J can be the models for female university students who have issues such as marriage, pregnancy, promotions, and transfers which can be discussed. We have to increase the numbers of female nuclear engineers to promote public trust in the safety of nuclear power plants. For this purpose, WiN-J encourages female university students to enter the nuclear industry. We recognize that to gain people's understanding of and trust in nuclear energy may take a long time. WiN-J will continue to fulfill our challenging mission for the peaceful use of nuclear energy. (author)

  8. A Self-Adaptive Model-Based Wi-Fi Indoor Localization Method.

    Science.gov (United States)

    Tuta, Jure; Juric, Matjaz B

    2016-12-06

    This paper presents a novel method for indoor localization, developed with the main aim of making it useful for real-world deployments. Many indoor localization methods exist, yet they have several disadvantages in real-world deployments-some are static, which is not suitable for long-term usage; some require costly human recalibration procedures; and others require special hardware such as Wi-Fi anchors and transponders. Our method is self-calibrating and self-adaptive thus maintenance free and based on Wi-Fi only. We have employed two well-known propagation models-free space path loss and ITU models-which we have extended with additional parameters for better propagation simulation. Our self-calibrating procedure utilizes one propagation model to infer parameters of the space and the other to simulate the propagation of the signal without requiring any additional hardware beside Wi-Fi access points, which is suitable for real-world usage. Our method is also one of the few model-based Wi-Fi only self-adaptive approaches that do not require the mobile terminal to be in the access-point mode. The only input requirements of the method are Wi-Fi access point positions, and positions and properties of the walls. Our method has been evaluated in single- and multi-room environments, with measured mean error of 2-3 and 3-4 m, respectively, which is similar to existing methods. The evaluation has proven that usable localization accuracy can be achieved in real-world environments solely by the proposed Wi-Fi method that relies on simple hardware and software requirements.

  9. What Can WiN Learn From Other Male Dominated Industries

    International Nuclear Information System (INIS)

    Thomas, C.

    2015-01-01

    Thomas Thor Associates is an Executive Recruitment company solely dedicated to the Nuclear industry. We have been involved with WiN UK in 2014–2015 to help them develop their own organization, this research was part of our partnership. The main purpose of this paper is to provide a clear picture of the techniques that are used by organizations similar to WiN, and business in other industries that are similar to Nuclear, to attract more women to pursue a career in a particular industry, and to support retention and career progression of women in these industries. This paper has taken a look at all industries that require technical and engineering staff, after which the Mining, Oil and Gas, Petro-chemicals, Rail, Renewable Energy, Technology and Construction industries were found to show most similarities with Nuclear, in terms of the technical staff required and their structure on gender diversity. From here, case studies of industry organizations and professional business have been prepared in order to inform WiN of best practice in these industries and provide a benchmark for future WiN operations. Finally, the report results into giving recommendations on projects WiN could add to their current approach to achieve their objectives. The recommendations are based on the results from the case studies, focusing on attracting, recruiting, retaining and developing female professionals. In summary, the recommendations are to: highlight potential career paths for women in Nuclear, educate women on Nuclear, support the development of women and to help companies to increase their bottom line by getting WiN certified. (author)

  10. Nagyszombat and the stars

    Science.gov (United States)

    Zsoldos, E.

    Péter Pázmány, founder of the University of Nagyszombat, considered stars in terms inherited from medieval times. The theses, connected to the university graduation, soon left this definition, and imagined stars as made from sublunar elements. The 1753 decree of the Empress Maria Theresia ordered university professors to publish textbooks. These textbooks, together with the theses showed a definite improvement, defining stars according to contemporary knowledge.

  11. Evolution of massive stars

    International Nuclear Information System (INIS)

    Loore, C. de

    1984-01-01

    The evolution of stars with masses larger than 15 sun masses is reviewed. These stars have large convective cores and lose a substantial fraction of their matter by stellar wind. The treatment of convection and the parameterisation of the stellar wind mass loss are analysed within the context of existing disagreements between theory and observation. The evolution of massive close binaries and the origin of Wolf-Rayet Stars and X-ray binaries is also sketched. (author)

  12. Positioning indoors with Wi-Fi devices of low-cost; Posicionamento em ambientes internos com dispositivos wi-fi de baixo custo

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Fabricio M.; Farias, Marcos S.; Carvalho, Paulo Victor R. de, E-mail: fabricio_mv1@hotmail.com, E-mail: msantana@ien.gov.br, E-mail: paulov@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Serviço de Instrumentação

    2017-07-01

    The rhythm of research development linked to location tracking is highly linked with the advancement of wireless sensor network and wireless technologies. A classic example is the Global Positioning System (GPS), where satellites are used to send signals to receivers on earth that use these signals to compute navigation information. However, as communication between the satellites and GPS receivers require radio propagation in line of sight, the GPS system usually only works outdoors. For the growing interest in research to position tracking indoors, you must use wireless devices based on Bluetooth or Wi-Fi technology (IEEE 802.11). The aim of this work is to show the development of applications using new Wi-Fi devices (ESP8266) for the estimation of positioning and location indoors.

  13. Inferring Person-to-person Proximity Using WiFi Signals

    DEFF Research Database (Denmark)

    Sapiezynski, Piotr; Stopczynski, Arkadiusz; Wind, David Kofoed

    2017-01-01

    scale is a technical challenge and many commonly used approaches—including RFID badges or Bluetooth scanning—offer only limited scalability. Here we show that it is possible, in a scalable and robust way, to accurately infer person-to-person physical proximity from the lists of WiFi access points...... measured by smartphones carried by the two individuals. Based on a longitudinal dataset of approximately 800 participants with ground-truth interactions collected over a year, we show that our model performs better than the current state-of-the-art. Our results demonstrate the value of WiFi signals...

  14. Access for Internet of Things using Smartphone as a Gateway utilizing LTE and WiFi

    DEFF Research Database (Denmark)

    Mathur, Prateek; Nielsen, Rasmus Hjorth; Prasad, Neeli R.

    2016-01-01

    Communicating the Internet of Things (IoT) data relying on Long-Term Evolution (LTE) and WiFi has been been presented in the relevant literature. However, this necessitates devices to have LTE/WiFi capability of their own, that has limitations in the form of power consumption, and radio access...... the data to the Internet. In this paper we present a system model wherein the smartphone functions as a gateway for the IoT devices operating on NFC, ZigBee and Bluetooth. The smartphone functioning as a gateway for transferring IoT data. The system modelled in the form of a Markov Chain based...

  15. RSSI BASED LOCATION ESTIMATION IN A WI-FI ENVIRONMENT: AN EXPERIMENTAL STUDY

    Directory of Open Access Journals (Sweden)

    M. Ganesh Madhan

    2014-12-01

    Full Text Available In real life situations, location estimation of moving objects, armed personnel are of great importance. In this paper, we have attempted to locate targets which are mobile in a Wi-Fi environment. Radio Frequency (RF localization techniques based on Received Signal Strength Indication (RSSI algorithms are used. This study utilises Wireless Mon tool, software to provide complete technical information regarding received signal strength obtained from different wireless access points available in a campus Wi-Fi environment, considered for the study. All simulations have been done in MATLAB. The target location estimated by this approach agrees well with the actual GPS data.

  16. The SeaWiFS Quality Monitor: A Portable Field Calibration Light Source

    Science.gov (United States)

    Shaw, Ping-Shine; Johnson, B. Carol; Hooker, Stanford B.; Lynch, Don

    1997-01-01

    A portable and stable source, the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Quality Monitor, has been developed for use as a field instrument. The source can be used with either radiance- or irradiance-measuring sensors to transfer the laboratory calibration to the field so that the stability of the sensors can be monitored during the experiment. Temperature-controlled silicon photodiodes with colored glass filters are used to monitor the stability of the SeaWiFS Quality Monitor.

  17. Cognitive radio-based transmission energy management in Wi-Fi nodes

    CSIR Research Space (South Africa)

    Olwal, TO

    2012-10-01

    Full Text Available following the adoption of the proposed CR-TEM method. The execution of the CR-TEM fosters more users? adoption of the internet services and a corresponding network gain. Figure 5: Expected network performance Fi 3 M d l f C TEM i Wi Fi d Fi 5 E d k f....kashan.co.za] INTRODUCTION The recent increased demand for various internet services, shown in Figure 1, to be delivered through energy-efficient wireless infrastructures such as Wi-Fi routers has compelled the need for a new research & development (R&D) paradigm...

  18. Dual Y-Shaped Monopole Antenna for Dual-Band WLAN/WiMAX Operations

    Directory of Open Access Journals (Sweden)

    Huiqing Zhai

    2014-01-01

    Full Text Available A dual-band design of monopole antenna with two coupled Y-shaped strips for WLAN/WiMAX applications is presented. By the introduction of dual Y-shaped strips, two separated impedance bandwidths of 22.4% (3.28~4.10 GHz and 19.2% (4.90~5.94 GHz can be obtained to meet the specifications of the WLAN/WiMAX communication band applications. The proposed antenna is successfully simulated, designed, and measured, demonstrating the matched impedance and good radiation characteristics with an overall dimension of 17.7×26×1 mm3.

  19. Covering tree with stars

    DEFF Research Database (Denmark)

    Baumbach, Jan; Guo, Jian-Ying; Ibragimov, Rashid

    2013-01-01

    We study the tree edit distance problem with edge deletions and edge insertions as edit operations. We reformulate a special case of this problem as Covering Tree with Stars (CTS): given a tree T and a set of stars, can we connect the stars in by adding edges between them such that the resulting...... tree is isomorphic to T? We prove that in the general setting, CST is NP-complete, which implies that the tree edit distance considered here is also NP-hard, even when both input trees having diameters bounded by 10. We also show that, when the number of distinct stars is bounded by a constant k, CTS...

  20. Covering tree with stars

    DEFF Research Database (Denmark)

    Baumbach, Jan; Guo, Jiong; Ibragimov, Rashid

    2015-01-01

    We study the tree edit distance problem with edge deletions and edge insertions as edit operations. We reformulate a special case of this problem as Covering Tree with Stars (CTS): given a tree T and a set of stars, can we connect the stars in by adding edges between them such that the resulting...... tree is isomorphic to T? We prove that in the general setting, CST is NP-complete, which implies that the tree edit distance considered here is also NP-hard, even when both input trees having diameters bounded by 10. We also show that, when the number of distinct stars is bounded by a constant k, CTS...

  1. Massive soliton stars

    Science.gov (United States)

    Chiu, Hong-Yee

    1990-01-01

    The structure of nontopological solutions of Einstein field equations as proposed by Friedberg, Lee, and Pang (1987) is examined. This analysis incorporates finite temperature effects and pair creation. Quarks are assumed to be the only species that exist in interior of soliton stars. The possibility of primordial creation of soliton stars in the incomplete decay of the degenerate vacuum in early universe is explored. Because of dominance of pair creation inside soliton stars, the luminosity of soliton stars is not determined by its radiative transfer characteristics, and the surface temperature of soliton stars can be the same as its interior temperature. It is possible that soliton stars are intense X-ray radiators at large distances. Soliton stars are nearly 100 percent efficient energy converters, converting the rest energy of baryons entering the interior into radiation. It is possible that a sizable number of baryons may also be trapped inside soliton stars during early epochs of the universe. In addition, if soliton stars exist they could assume the role played by massive black holes in galactic centers.

  2. Interacting binary stars

    CERN Document Server

    Sahade, Jorge; Ter Haar, D

    1978-01-01

    Interacting Binary Stars deals with the development, ideas, and problems in the study of interacting binary stars. The book consolidates the information that is scattered over many publications and papers and gives an account of important discoveries with relevant historical background. Chapters are devoted to the presentation and discussion of the different facets of the field, such as historical account of the development in the field of study of binary stars; the Roche equipotential surfaces; methods and techniques in space astronomy; and enumeration of binary star systems that are studied

  3. ENERGY STAR Unit Reports

    Data.gov (United States)

    Department of Housing and Urban Development — These quarterly Federal Fiscal Year performance reports track the ENERGY STAR qualified HOME units that Participating Jurisdictions record in HUD's Integrated...

  4. Horizontal Branch stars as AmFm/HgMn stars

    OpenAIRE

    Michaud, G.; Richer, J.

    2008-01-01

    Recent observations and models for horizontal branch stars are briefly described and compared to models for AmFm stars. The limitations of those models are emphasized by a comparison to observations and models for HgMn stars.

  5. An Indoor Continuous Positioning Algorithm on the Move by Fusing Sensors and Wi-Fi on Smartphones

    Directory of Open Access Journals (Sweden)

    Huaiyu Li

    2015-12-01

    Full Text Available Wi-Fi indoor positioning algorithms experience large positioning error and low stability when continuously positioning terminals that are on the move. This paper proposes a novel indoor continuous positioning algorithm that is on the move, fusing sensors and Wi-Fi on smartphones. The main innovative points include an improved Wi-Fi positioning algorithm and a novel positioning fusion algorithm named the Trust Chain Positioning Fusion (TCPF algorithm. The improved Wi-Fi positioning algorithm was designed based on the properties of Wi-Fi signals on the move, which are found in a novel “quasi-dynamic” Wi-Fi signal experiment. The TCPF algorithm is proposed to realize the “process-level” fusion of Wi-Fi and Pedestrians Dead Reckoning (PDR positioning, including three parts: trusted point determination, trust state and positioning fusion algorithm. An experiment is carried out for verification in a typical indoor environment, and the average positioning error on the move is 1.36 m, a decrease of 28.8% compared to an existing algorithm. The results show that the proposed algorithm can effectively reduce the influence caused by the unstable Wi-Fi signals, and improve the accuracy and stability of indoor continuous positioning on the move.

  6. Safe at Any Speed: Securing Your Wi-Fi Network Is Easier and More Important than You Might Think

    Science.gov (United States)

    Branzburg, Jeffrey

    2007-01-01

    In this article, the author relates how he discovered that not all Wi-Fi networks are secure. As such, he developed several strategies on how he can be secured whenever he connects to the Internet through a Wi-Fi connection. He discusses how one can change passwords, explains the process of encryption, and provides suggestions on other security…

  7. An Indoor Continuous Positioning Algorithm on the Move by Fusing Sensors and Wi-Fi on Smartphones.

    Science.gov (United States)

    Li, Huaiyu; Chen, Xiuwan; Jing, Guifei; Wang, Yuan; Cao, Yanfeng; Li, Fei; Zhang, Xinlong; Xiao, Han

    2015-12-11

    Wi-Fi indoor positioning algorithms experience large positioning error and low stability when continuously positioning terminals that are on the move. This paper proposes a novel indoor continuous positioning algorithm that is on the move, fusing sensors and Wi-Fi on smartphones. The main innovative points include an improved Wi-Fi positioning algorithm and a novel positioning fusion algorithm named the Trust Chain Positioning Fusion (TCPF) algorithm. The improved Wi-Fi positioning algorithm was designed based on the properties of Wi-Fi signals on the move, which are found in a novel "quasi-dynamic" Wi-Fi signal experiment. The TCPF algorithm is proposed to realize the "process-level" fusion of Wi-Fi and Pedestrians Dead Reckoning (PDR) positioning, including three parts: trusted point determination, trust state and positioning fusion algorithm. An experiment is carried out for verification in a typical indoor environment, and the average positioning error on the move is 1.36 m, a decrease of 28.8% compared to an existing algorithm. The results show that the proposed algorithm can effectively reduce the influence caused by the unstable Wi-Fi signals, and improve the accuracy and stability of indoor continuous positioning on the move.

  8. Converged delivery of WiMAX and wireline services over an extended reach passive optical access network

    DEFF Research Database (Denmark)

    Osadchiy, Alexey Vladimirovich; Prince, Kamau; Tafur Monroy, Idelfonso

    2010-01-01

    In this paper we present long-reach fiber access links supporting transmission of Worldwide Interoperability for Microwave Access (WiMAX) compliant signals. We present bi-directional full-duplex transmission of 256-state quadrature amplitude modulation (256-QAM) modulated WiMAX-compliant signals ...

  9. 78 FR 39608 - Safety Zone; Summer in the City Water Ski Show; Fox River, Green Bay, WI

    Science.gov (United States)

    2013-07-02

    ...-AA00 Safety Zone; Summer in the City Water Ski Show; Fox River, Green Bay, WI AGENCY: Coast Guard, DHS... and three boats, operating within the main channel of the Fox River. The Captain of the Port, Lake... River in Green Bay, WI. This safety zone is intended to restrict vessels from a portion of the Fox River...

  10. SeaWiFS Deep Blue Aerosol Optical Thickness Monthly Level 3 Climatology Data Gridded at 1.0 Degrees V004

    Data.gov (United States)

    National Aeronautics and Space Administration — The SeaWiFS Deep Blue Level 3 Monthly Climatology Product contains monthly global climatology gridded (1 x 1 deg) data derived from SeaWiFS Deep Blue Level 3 monthly...

  11. Merging strangeon stars

    Science.gov (United States)

    Lai, Xiao-Yu; Yu, Yun-Wei; Zhou, En-Ping; Li, Yun-Yang; Xu, Ren-Xin

    2018-02-01

    The state of supranuclear matter in compact stars remains puzzling, and it is argued that pulsars could be strangeon stars. What would happen if binary strangeon stars merge? This kind of merger could result in the formation of a hyper-massive strangeon star, accompanied by bursts of gravitational waves and electromagnetic radiation (and even a strangeon kilonova explained in the paper). The tidal polarizability of binary strangeon stars is different from that of binary neutron stars, because a strangeon star is self-bound on the surface by the fundamental strong force while a neutron star by the gravity, and their equations of state are different. Our calculation shows that the tidal polarizability of merging binary strangeon stars is favored by GW170817. Three kinds of kilonovae (i.e., of neutron, quark and strangeon) are discussed, and the light curve of the kilonova AT 2017 gfo following GW170817 could be explained by considering the decaying strangeon nuggets and remnant star spin-down. Additionally, the energy ejected to the fireball around the nascent remnant strangeon star, being manifested as a gamma-ray burst, is calculated. It is found that, after a prompt burst, an X-ray plateau could follow in a timescale of 102 ‑ 103 s. Certainly, the results could be tested also by further observational synergies between gravitational wave detectors (e.g., Advanced LIGO) and X-ray telescopes (e.g., the Chinese HXMT satellite and eXTP mission), and especially if the detected gravitational wave form is checked by peculiar equations of state provided by the numerical relativistical simulation.

  12. Stars and Flowers, Flowers and Stars

    Science.gov (United States)

    Minti, Hari

    2012-12-01

    The author, a graduated from the Bucharest University (1964), actually living and working in Israel, concerns his book to variable stars and flowers, two domains of his interest. The analogies includes double stars, eclipsing double stars, eclipses, Big Bang. The book contains 34 chapters, each of which concerns various relations between astronomy and other sciences and pseudosciences such as Psychology, Religion, Geology, Computers and Astrology (to which the author is not an adherent). A special part of the book is dedicated to archeoastronomy and ethnoastronomy, as well as to history of astronomy. Between the main points of interest of these parts: ancient sanctuaries in Sarmizegetusa (Dacia), Stone Henge(UK) and other. The last chapter of the book is dedicated to flowers. The book is richly illustrated. It is designed for a wide circle of readers.

  13. Convective overshooting in stars

    NARCIS (Netherlands)

    Andrássy, R.

    2015-01-01

    Numerous observations provide evidence that the standard picture, in which convective mixing is limited to the unstable layers of a star, is incomplete. The mixing layers in real stars are significantly more extended than what the standard models predict. Some of the observations require changing

  14. Hyperons in neutron stars

    International Nuclear Information System (INIS)

    Glendenning, N.K.

    1986-04-01

    Generalized beta equilibrium involving nucleons, hyperons, and isobars is examined for neutron star matter. The hyperons produce a considerable softening of the equation of state. It is shown that the observed masses of neutron stars can be used to settle a recent controversy concerning the nuclear compressibility. Compressibilities less than 200 MeV are incompatible with observed masses. 7 refs., 9 figs

  15. PAHs and star formation

    NARCIS (Netherlands)

    Tielens, AGGM; Peeters, E; Bakes, ELO; Spoon, HWW; Hony, S; Johnstone, D; Adams, FC; Lin, DNC; Neufeld, DA; Ostriker, EC

    2004-01-01

    Strong IR emission features at 3.3, 6.2, 7.7, 8.6, and 11.2 mum are a common characteristic of regions of massive star formation. These features are carried by large (similar to 50 C-atom) Polycyclic Aromatic Hydrocarbon molecules which are pumped by the strong FUV photon flux from these stars.

  16. Science Through ARts (STAR)

    Science.gov (United States)

    Kolecki, Joseph; Petersen, Ruth; Williams, Lawrence

    2002-01-01

    Science Through ARts (STAR) is an educational initiative designed to teach students through a multidisciplinary approach to learning. This presentation describes the STAR pilot project, which will use Mars exploration as the topic to be integrated. Schools from the United Kingdom, Japan, the United States, and possibly eastern Europe are expected to participate in the pilot project.

  17. Neutron Stars and Pulsars

    CERN Document Server

    Becker, Werner

    2009-01-01

    Neutron stars are the most compact astronomical objects in the universe which are accessible by direct observation. Studying neutron stars means studying physics in regimes unattainable in any terrestrial laboratory. Understanding their observed complex phenomena requires a wide range of scientific disciplines, including the nuclear and condensed matter physics of very dense matter in neutron star interiors, plasma physics and quantum electrodynamics of magnetospheres, and the relativistic magneto-hydrodynamics of electron-positron pulsar winds interacting with some ambient medium. Not to mention the test bed neutron stars provide for general relativity theories, and their importance as potential sources of gravitational waves. It is this variety of disciplines which, among others, makes neutron star research so fascinating, not only for those who have been working in the field for many years but also for students and young scientists. The aim of this book is to serve as a reference work which not only review...

  18. Rotating stars in relativity.

    Science.gov (United States)

    Paschalidis, Vasileios; Stergioulas, Nikolaos

    2017-01-01

    Rotating relativistic stars have been studied extensively in recent years, both theoretically and observationally, because of the information they might yield about the equation of state of matter at extremely high densities and because they are considered to be promising sources of gravitational waves. The latest theoretical understanding of rotating stars in relativity is reviewed in this updated article. The sections on equilibrium properties and on nonaxisymmetric oscillations and instabilities in f -modes and r -modes have been updated. Several new sections have been added on equilibria in modified theories of gravity, approximate universal relationships, the one-arm spiral instability, on analytic solutions for the exterior spacetime, rotating stars in LMXBs, rotating strange stars, and on rotating stars in numerical relativity including both hydrodynamic and magnetohydrodynamic studies of these objects.

  19. 78 FR 42016 - Safety Zone; Discovery World Fireworks, Milwaukee Harbor, Milwaukee, WI

    Science.gov (United States)

    2013-07-15

    ... economically affect it. 3. Assistance for Small Entities Under section 213(a) of the Small Business Regulatory...-AA00 Safety Zone; Discovery World Fireworks, Milwaukee Harbor, Milwaukee, WI AGENCY: Coast Guard, DHS... Milwaukee Harbor due to 4 fireworks displays at Discovery World Pier. This safety zone is necessary to...

  20. 75 FR 25308 - Environmental Impact Statement: Winnebago County, IL and Rock County, WI

    Science.gov (United States)

    2010-05-07

    ... DEPARTMENT OF TRANSPORTATION Federal Highway Administration Environmental Impact Statement: Winnebago County, IL and Rock County, WI AGENCY: Federal Highway Administration (FHWA), DOT. ACTION: Notice... Nye School Road northwest of Beloit, Rock County, Wisconsin to the interchange of Rockton Road and I...

  1. Chlorophyll-a, Orbview-2 SeaWiFS, 0.0125 degrees, West US

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes chlorophyll-a concentration images from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) on the Orbview-2 satellite. Because data is...

  2. Chlorophyll-a, Orbview-2 SeaWiFS, 0.04167 degrees, Alaska, Science Quality

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NASA GSFC Ocean Color Web distributes science-quality chlorophyll-a concentration data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) on the Orbview-2...

  3. Insecure Network, Unknown Connection: Understanding Wi-Fi Privacy Assumptions of Mobile Device Users

    Directory of Open Access Journals (Sweden)

    Bram Bonné

    2017-07-01

    Full Text Available Smartphones and other mobile devices have proliferated in the past five years. The expectation of mobile device users to always be online has led to Wi-Fi networks being offered by a variety of providers. Using these networks introduces multiple security risks. In this work, we assess to what extent the privacy stance of mobile device users corresponds with their actual behavior by conducting a study with 108 participants. Our methodology consists of monitoring Wi-Fi networks that the participants’ devices connect to and the connections made by apps on these devices, for a period of 30 days. Afterwards, participants are surveyed about their awareness and privacy sensitiveness. We show that while a higher expertise in computer networks corresponds to more awareness about the connections made by apps, neither this expertise nor the actual privacy stance of the participant translates to better security habits. Moreover, participants in general were unaware about a significant part of connections made by apps on their devices, a matter that is worsened by the fact that one third of Wi-Fi networks that participants connect to do not have any security enabled. Based on our results, we provide recommendations to network providers, developers and users on how to improve Wi-Fi security for mobile devices.

  4. Klimatisering van de energieproducerende tuinbouwkas met FiWiHex warmtewisselaars : vooronderzoek Energie producerende kas

    NARCIS (Netherlands)

    Campen, J.B.; Zwart, de H.F.

    2005-01-01

    De stuurgroep 'Kas als energiebron' beoogt de realisatie van een pilotproject van een energieproducerende kas. In de in dit rapport beschreven uitvoeringsvorm wordt gebruik gemaakt van hoog-rendement FiWiHEx warmtewisselaars. Verkennende onderzoeken en initiërend design hebben geleid tot een eerste

  5. 75 FR 51851 - Weather Shield Manufacturing, Inc., Corporate Office, Medford, WI; Notice of Revised...

    Science.gov (United States)

    2010-08-23

    ...] [FR Doc No: 2010-20791] DEPARTMENT OF LABOR Employment and Training Administration [TA-W-64,725] Weather Shield Manufacturing, Inc., Corporate Office, Medford, WI; Notice of Revised Determination on... Adjustment Assistance (ATAA) on behalf of workers of Weather Shield Manufacturing, Inc., Corporate Office...

  6. Device-Free Passive Identity Identification via WiFi Signals.

    Science.gov (United States)

    Lv, Jiguang; Yang, Wu; Man, Dapeng

    2017-11-02

    Device-free passive identity identification attracts much attention in recent years, and it is a representative application in sensorless sensing. It can be used in many applications such as intrusion detection and smart building. Previous studies show the sensing potential of WiFi signals in a device-free passive manner. It is confirmed that human's gait is unique from each other similar to fingerprint and iris. However, the identification accuracy of existing approaches is not satisfactory in practice. In this paper, we present Wii, a device-free WiFi-based Identity Identification approach utilizing human's gait based on Channel State Information (CSI) of WiFi signals. Principle Component Analysis (PCA) and low pass filter are applied to remove the noises in the signals. We then extract several entities' gait features from both time and frequency domain, and select the most effective features according to information gain. Based on these features, Wii realizes stranger recognition through Gaussian Mixture Model (GMM) and identity identification through a Support Vector Machine (SVM) with Radial Basis Function (RBF) kernel. It is implemented using commercial WiFi devices and evaluated on a dataset with more than 1500 gait instances collected from eight subjects walking in a room. The results indicate that Wii can effectively recognize strangers and can achieves high identification accuracy with low computational cost. As a result, Wii has the potential to work in typical home security systems.

  7. Unscented Kalman Filter Algorithm for WiFi-PDR Integrated Indoor Positioning

    Directory of Open Access Journals (Sweden)

    CHEN GuoLiang

    2015-12-01

    Full Text Available Indoor positioning still faces lots of fundamental technical problems although it has been widely applied. A novel indoor positioning technology by using the smart phone with the assisting of the widely available and economically signals of WiFi is proposed. It also includes the principles and characteristics in indoor positioning. Firstly, improve the system's accuracy by fusing the WiFi fingerprinting positioning and PDR (ped estrian dead reckoning positioning with UKF (unscented Kalman filter. Secondly, improve the real-time performance by clustering the WiFi fingerprinting with k-means clustering algorithm. An investigation test was conducted at the indoor environment to learn about its performance on a HUAWEI P6-U06 smart phone. The result shows that compared to the pattern-matching system without clustering, an average reduction of 51% in the time cost can be obtained without degrading the positioning accuracy. When the state of personnel is walking, the average positioning error of WiFi is 7.76 m, the average positioning error of PDR is 4.57 m. After UKF fusing, the system's average positioning error is down to 1.24 m. It shows that the algorithm greatly improves the system's real-time and positioning accuracy.

  8. Complementing Security Breach of Authentication by Using Shared Authentication Information in Mobile WiMAX Networks

    Science.gov (United States)

    Kim, Youngwook; Lim, Hyoung-Kyu; Bahk, Saewoong

    The signalling protocol vulnerability opens DDoS problem in Mobile WiMAX networks. This letter proposes an authentication method that uses the unrevealed upper 64bits of Cipher-based MAC as a solution. It runs for MSs in idle mode and reduces the calculation complexity by 59% under DDoS attack while incurring 1% overhead under normal condition.

  9. 78 FR 20714 - Union Pacific Railroad Company-Abandonment Exemption-in Dunn County, WI.

    Science.gov (United States)

    2013-04-05

    ... Surface Transportation Board Union Pacific Railroad Company--Abandonment Exemption--in Dunn County, WI. Union Pacific Railroad Company (UP) filed a verified notice of exemption under 49 CFR part 1152 subpart... the Board should be sent to UP's representative: Mack H. Shumate, Jr., Senior General Attorney, Union...

  10. 76 FR 46626 - Safety Zone; Discovery World Private Wedding Firework Displays, Milwaukee, WI

    Science.gov (United States)

    2011-08-03

    ... could better evaluate its effects on them and participate in the rulemaking process. Small businesses...-AA00 Safety Zone; Discovery World Private Wedding Firework Displays, Milwaukee, WI AGENCY: Coast Guard... the public interest. Background and Purpose The Discovery World Private Wedding fireworks are a City...

  11. Considerations for Using Personal Wi-Fi Enabled Devices as "Clickers" in a Large University Class

    Science.gov (United States)

    Katz, Larry; Hallam, Megan C.; Duvall, Michael M.; Polsky, Zoe

    2017-01-01

    Interactive student response systems, commonly referred to as clickers, have increased in popularity in higher education classrooms as a means to improve engagement and enhance learning. Clicker systems come with handheld devices as well as a radio frequency receiver. A Wi-Fi connection to the receiver is possible, enabling students to use their…

  12. PILA: Sub-Meter Localization Using CSI from Commodity Wi-Fi Devices.

    Science.gov (United States)

    Tian, Zengshan; Li, Ze; Zhou, Mu; Jin, Yue; Wu, Zipeng

    2016-10-10

    The aim of this paper is to present a new indoor localization approach by employing the Angle-of-arrival (AOA) and Received Signal Strength (RSS) measurements in Wi-Fi network. To achieve this goal, we first collect the Channel State Information (CSI) by using the commodity Wi-Fi devices with our designed three antennas to estimate the AOA of Wi-Fi signal. Second, we propose a direct path identification algorithm to obtain the direct signal path for the sake of reducing the interference of multipath effect on the AOA estimation. Third, we construct a new objective function to solve the localization problem by integrating the AOA and RSS information. Although the localization problem is non-convex, we use the Second-order Cone Programming (SOCP) relaxation approach to transform it into a convex problem. Finally, the effectiveness of our approach is verified based on the prototype implementation by using the commodity Wi-Fi devices. The experimental results show that our approach can achieve the median error 0.7 m in the actual indoor environment.

  13. Using Wi-Fi to Save Energy via P2P Remote Execution

    DEFF Research Database (Denmark)

    Kristensen, Mads Darø; Bouvin, Niels Olof

    2010-01-01

    tasks. This paper presents energy measurements of a modern mobile computing device, showing that utilising the relatively large CPU of such a device is very expensive - even more so than using Wi-Fi. Experiments performed with the Scavenger cyber foraging system are presented; a system enabling easy...

  14. SKIN - Embodied Navigation Through WiFi Traffic Using Vibro-Tactile Feedback

    DEFF Research Database (Denmark)

    van den Boogaard, Bas; Orsted Jensen, Louise; Nielsen, Stefan Engelbrecht

    2018-01-01

    In today’s world, radio waves are an integral element of our daily lives but they are mostly hidden to human perception. In this paper we present SKIN, a wireless wearable system that creates a new interface between the human and WiFi signals employing sensory augmentation. SKIN translates nearby...

  15. 77 FR 27097 - LaCrosse Boiling Water Reactor, Exemption From Certain Requirements, Vernon County, WI

    Science.gov (United States)

    2012-05-08

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION LaCrosse Boiling Water Reactor, Exemption From Certain Requirements, Vernon County, WI AGENCY...) 73.55, for the LaCrosse Boiling Water Reactor (LACBWR). This Environmental Assessment (EA) has been...

  16. WiFiSiM: An Educational Tool for the Study and Design of Wireless Networks

    Science.gov (United States)

    Mateo Sanguino, T. J.; Serrano Lopez, C.; Marquez Hernandez, F. A.

    2013-01-01

    A new educational simulation tool designed for the generic study of wireless networks, the Wireless Fidelity Simulator (WiFiSim), is presented in this paper. The goal of this work was to create and implement a didactic tool to improve the teaching and learning of computer networks by means of two complementary strategies: simulating the behavior…

  17. A novel particle filter approach for indoor positioning by fusing WiFi and inertial sensors

    Directory of Open Access Journals (Sweden)

    Zhu Nan

    2015-12-01

    Full Text Available WiFi fingerprinting is the method of recording WiFi signal strength from access points (AP along with the positions at which they were recorded, and later matching those to new measurements for indoor positioning. Inertial positioning utilizes the accelerometer and gyroscopes for pedestrian positioning. However, both methods have their limitations, such as the WiFi fluctuations and the accumulative error of inertial sensors. Usually, the filtering method is used for integrating the two approaches to achieve better location accuracy. In the real environments, especially in the indoor field, the APs could be sparse and short range. To overcome the limitations, a novel particle filter approach based on Rao Blackwellized particle filter (RBPF is presented in this paper. The indoor environment is divided into several local maps, which are assumed to be independent of each other. The local areas are estimated by the local particle filter, whereas the global areas are combined by the global particle filter. The algorithm has been investigated by real field trials using a WiFi tablet on hand with an inertial sensor on foot. It could be concluded that the proposed method reduces the complexity of the positioning algorithm obviously, as well as offers a significant improvement in position accuracy compared to other conventional algorithms, allowing indoor positioning error below 1.2 m.

  18. Throughput Gain Using Threshold-Based Multiuser Scheduling in WiMAX OFDMA

    Directory of Open Access Journals (Sweden)

    Sulyman AhmedIyanda

    2011-01-01

    Full Text Available This paper presents the analysis of the throughput enhancement possible using threshold-based multiuser scheduling in WiMAX OFDMA. We consider a point-to-multipoint (PMP WiMAX network where base station (BS schedules downlink packets for simultaneous transmissions to multiple users using the WiMAX OFDMA system. WiMAX OFDMA standard specifies several subcarrier permutation options, such as the partial usage of subcarriers (PUSC, full usage of subcarrier (FUSC, and the band adaptive modulation and coding (band-AMC among others, for mapping the physical subcarriers into logical subchannels assigned to users by the BS schedulers. In this paper, we propose the use of threshold testing prior to the process of subchannel assignment to users by the BS scheduler, as a means of throughput enhancement. In the proposed threshold-based multiuser scheduling scheme, the BS scheduler selects at any time instant users whose channel gains in the available subchannels equal or exceed a predetermined energy threshold. Thus, only users who can maximize BS throughput on the available subchannels are assigned data transmission opportunities which enhance the BS data rate, albeit at the expense of fairness to users. We quantify the throughput enhancement of the proposed system and illustrate its benefits by numerical simulations.

  19. WiFi Data Acquisition System Applied to a Photovoltaic Powered Water Pumping Plant

    Directory of Open Access Journals (Sweden)

    Sandro César Silveira JUCÁ

    2015-02-01

    Full Text Available The present paper describes how to design and assemble a low cost online monitoring and WiFi data acquisition system using free software applied to microgeneration based on renewable energy sources. The development of online monitoring systems for microgeneration plants based on renewable energy sources is becoming more important, considering that monitoring and data acquisition systems are applicable in stages of the microgeneration process. The monitoring and data acquisition WiFi system was developed using an embedded WiFi modem (Wifly coupled to a microcontrolled board based on the free tool SanUSB. This monitoring system was applied to a photovoltaic (PV water pumping plant without batteries, so as the control system and the wireless communication with the online server, which is also autonomous and powered by PV panel. The free software for online monitoring and WiFi data acquisition allows the analysis of stored data and charts through mobile devices as notebooks, tablets and smartphones.

  20. Device-Free Passive Identity Identification via WiFi Signals

    Directory of Open Access Journals (Sweden)

    Jiguang Lv

    2017-11-01

    Full Text Available Device-free passive identity identification attracts much attention in recent years, and it is a representative application in sensorless sensing. It can be used in many applications such as intrusion detection and smart building. Previous studies show the sensing potential of WiFi signals in a device-free passive manner. It is confirmed that human’s gait is unique from each other similar to fingerprint and iris. However, the identification accuracy of existing approaches is not satisfactory in practice. In this paper, we present Wii, a device-free WiFi-based Identity Identification approach utilizing human’s gait based on Channel State Information (CSI of WiFi signals. Principle Component Analysis (PCA and low pass filter are applied to remove the noises in the signals. We then extract several entities’ gait features from both time and frequency domain, and select the most effective features according to information gain. Based on these features, Wii realizes stranger recognition through Gaussian Mixture Model (GMM and identity identification through a Support Vector Machine (SVM with Radial Basis Function (RBF kernel. It is implemented using commercial WiFi devices and evaluated on a dataset with more than 1500 gait instances collected from eight subjects walking in a room. The results indicate that Wii can effectively recognize strangers and can achieves high identification accuracy with low computational cost. As a result, Wii has the potential to work in typical home security systems.

  1. 78 FR 48900 - Notice of Inventory Completion: State Historical Society of Wisconsin, Madison, WI

    Science.gov (United States)

    2013-08-12

    .... 3003, of the completion of an inventory of human remains under the control of the State Historical....R50000] Notice of Inventory Completion: State Historical Society of Wisconsin, Madison, WI AGENCY... Wisconsin has completed an inventory of human remains, in consultation with the appropriate Indian tribes or...

  2. 76 FR 50172 - Designation of New Grantee, Foreign-Trade Zone 41, Milwaukee, WI

    Science.gov (United States)

    2011-08-12

    ... DEPARTMENT OF COMMERCE Foreign-Trade Zones Board [Order No. 1778] Designation of New Grantee, Foreign-Trade Zone 41, Milwaukee, WI Pursuant to its authority under the Foreign-Trade Zones Act of June 18, 1934, as amended (19 U.S.C. 81a-81u), and the Foreign-Trade Zones Board Regulations (15 CFR part...

  3. 75 FR 51757 - Foreign-Trade Zone 167-Green Bay, WI; Site Renumbering Notice

    Science.gov (United States)

    2010-08-23

    ... DEPARTMENT OF COMMERCE Foreign-Trade Zones Board Foreign-Trade Zone 167--Green Bay, WI; Site Renumbering Notice Foreign-Trade Zone 167 was approved by the FTZ Board on August 23, 1990 (Board Order 483... Elizabeth Whiteman at [email protected]trade.gov or (202) 482-0473. Dated: August 17, 2010. Andrew...

  4. WiN Argentina: Re Launch of National Chapter and New Activities

    International Nuclear Information System (INIS)

    Sayan, J.; Gervasoni, J.; Cantargi, F.; Cintas, A.; Garea, V.

    2015-01-01

    Women of the Argentinian Nuclear Sector have shared WiN Global’s vision since its birth in 1992. Many have become active members and participated in its Annual Conferences, by presenting papers or country reports (Sweden, 1995 and Russia 1996, Taiwan 1998). Due to several drastic changes in the Sector, such as projects cancellations and reduction of personnel, occurred during the late 1990’s, the National Chapter reduced its activities. Thanks to the restless work of its founder, Dr. Maela Viirsoo, and a group of new Members, the Chapter has been recently re-launched at the 40th Annual Meeting of the Argentinian Nuclear Technology Association (AATN) and new adherents have represented the country in last year’s WiN Global Annual Conference held in Australia. In this presentation, we will show our new membership and governing structure in order to fulfill the WiN Charter’s obligations and WiN Global “Rules and Procedures”. We will also present the planned activities to promote the benefits of nuclear technologies from women’s perspective. Professional women working in several nuclear fields, such as: science and technology, health, cultural, educational and social will improve the community perception towards nuclear technology by organizing lectures, exchanging ideas and stimulating joint initiatives in the educational local system. (author)

  5. OPTIMASI POSISI PILOT MENGGUNAKAN ALGORITMA GENETIKA UNTUK MENINGKATKAN KINERJA Wi-Fi 802.11n

    Directory of Open Access Journals (Sweden)

    Wahyul Amien Syafei

    2013-12-01

    Full Text Available Wi-Fi is wireless communication technology that  used widely not only for accessing the internet but also communicating data, image, voice and video. The newest wi-fi technology is 802.11n as an extention of 802.11a/b/g. By  combining OFDM and MIMO techniques it can provide throughput up to 600Mbps. One of important factors to achieve such high throughput is the pilot position in training sequence. Wi-fi802.11n allocates it’s pilots orthogonally. This research optimizes the pilot location using Genetic Algorithm Differential Evolution. Optimum pilot position improves the accuracy of synchronization which leads to enhance the performance. The invented optimum pilot position set then be implemented into wi-fi 802.11n simulator to be analyzed the performance enhancement which represented in grafic BER vs SNR curve.Run test under channel model B and D proof that the invented optimum pilot position gives performance enhancement of 0,5 dB and maintain it’s stability compared towi-fi 802.11n system with  set ortogonal pilot position.

  6. Computer Simulation and Field Experiment for Downlink Multiuser MIMO in Mobile WiMAX System.

    Science.gov (United States)

    Yamaguchi, Kazuhiro; Nagahashi, Takaharu; Akiyama, Takuya; Matsue, Hideaki; Uekado, Kunio; Namera, Takakazu; Fukui, Hiroshi; Nanamatsu, Satoshi

    2015-01-01

    The transmission performance for a downlink mobile WiMAX system with multiuser multiple-input multiple-output (MU-MIMO) systems in a computer simulation and field experiment is described. In computer simulation, a MU-MIMO transmission system can be realized by using the block diagonalization (BD) algorithm, and each user can receive signals without any signal interference from other users. The bit error rate (BER) performance and channel capacity in accordance with modulation schemes and the number of streams were simulated in a spatially correlated multipath fading environment. Furthermore, we propose a method for evaluating the transmission performance for this downlink mobile WiMAX system in this environment by using the computer simulation. In the field experiment, the received power and downlink throughput in the UDP layer were measured on an experimental mobile WiMAX system developed in Azumino City in Japan. In comparison with the simulated and experimented results, the measured maximum throughput performance in the downlink had almost the same performance as the simulated throughput. It was confirmed that the experimental mobile WiMAX system for MU-MIMO transmission successfully increased the total channel capacity of the system.

  7. 78 FR 19158 - Safety Zone; USA Triathlon, Milwaukee Harbor, Milwaukee, WI

    Science.gov (United States)

    2013-03-29

    ...-AA00 Safety Zone; USA Triathlon, Milwaukee Harbor, Milwaukee, WI AGENCY: Coast Guard, DHS. ACTION... (adjusted for inflation) or more in any one year. Though this proposed rule would not result in such... Delegation No. 0170.1. 2. Add Sec. 165.T09-0140 to read as follows: Sec. 165.T09-0140 Safety Zone; USA...

  8. 78 FR 31415 - Safety Zone; USA Triathlon; Milwaukee Harbor, Milwaukee, WI

    Science.gov (United States)

    2013-05-24

    ...-AA00 Safety Zone; USA Triathlon; Milwaukee Harbor, Milwaukee, WI AGENCY: Coast Guard, DHS. ACTION... (adjusted for inflation) or more in any one year. Though this rule would not result in such an expenditure.... Add Sec. 165.T09-0140 to read as follows: Sec. 165.T09-0140 Safety Zone; USA Triathlon, Milwaukee...

  9. TCP Performance over Wi-Fi: Joint Impact of Buffer and Channel Losses

    NARCIS (Netherlands)

    Pokhrel, S.R.; Panda, M.; Vu, H.L.; Mandjes, M.

    2016-01-01

    We propose an analytical model for a Wi-Fi network acting as a last-mile Internet access with multiple long-lived TCP connections on both the up and down links. Our model considers the joint impact of buffer losses at the access point, contention at the medium access control layer, and packet losses

  10. An investigation of scalable anomaly detection techniques for a large network of Wi-Fi hotspots

    CSIR Research Space (South Africa)

    Machaka, P

    2015-01-01

    Full Text Available . The Neural Networks, Bayesian Networks and Artificial Immune Systems were used for this experiment. Using a set of data extracted from a live network of Wi-Fi hotspots managed by an ISP; we integrated algorithms into a data collection system to detect...

  11. Experimental evaluation of high speed impulse radio UWB interference on WiMAX narrowband systems

    DEFF Research Database (Denmark)

    Yu, Xianbin; Yin, Xiaoli; Tafur Monroy, Idelfonso

    2010-01-01

    Interference of high speed impulse radio ultrawideband (IR-UWB) on 5.735GHz single carrier 64/256-QAM WiMAX narrowband signals is experimentally investigated. The experimental results indicate that the coexistence of 625Mbps and 2Gbps IR-UWB signals causes penalties of 3dB and 0.5dB respectively ...... to the WiMAX channel. At higher bit rates, IR-UWB technology is therefore expected to reduce its interference on WiMAX signals. This work serves as further motivation for the exploration of IR-UWB systems with higher speed and higher capacity.......Interference of high speed impulse radio ultrawideband (IR-UWB) on 5.735GHz single carrier 64/256-QAM WiMAX narrowband signals is experimentally investigated. The experimental results indicate that the coexistence of 625Mbps and 2Gbps IR-UWB signals causes penalties of 3dB and 0.5dB respectively...

  12. Chlorophyll-a, Orbview-2 SeaWiFS, 0.1 degrees, Global

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NASA GSFC Ocean Color Web distributes science-quality chlorophyll-a concentration data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) on the Orbview-2...

  13. Design and development of plasma antenna for wi-fi application | Ja ...

    African Journals Online (AJOL)

    In this work the commercial fluorescent lamp was chosen because it was low cost to produce plasma element. The plasma antenna in this research was made from fluorescent lamp that functioned as a radiating element with target frequency at 2.4 GHz for Wi-Fi application. The commercial fluorescent lamp consisted of ...

  14. Monte Carlo simulation of star/linear and star/star blends with chemically identical monomers

    Energy Technology Data Exchange (ETDEWEB)

    Theodorakis, P E [Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina (Greece); Avgeropoulos, A [Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina (Greece); Freire, J J [Departamento de Ciencias y Tecnicas FisicoquImicas, Universidad Nacional de Educacion a Distancia, Facultad de Ciencias, Senda del Rey 9, 28040 Madrid (Spain); Kosmas, M [Department of Chemistry, University of Ioannina, 45110 Ioannina (Greece); Vlahos, C [Department of Chemistry, University of Ioannina, 45110 Ioannina (Greece)

    2007-11-21

    The effects of chain size and architectural asymmetry on the miscibility of blends with chemically identical monomers, differing only in their molecular weight and architecture, are studied via Monte Carlo simulation by using the bond fluctuation model. Namely, we consider blends composed of linear/linear, star/linear and star/star chains. We found that linear/linear blends are more miscible than the corresponding star/star mixtures. In star/linear blends, the increase in the volume fraction of the star chains increases the miscibility. For both star/linear and star/star blends, the miscibility decreases with the increase in star functionality. When we increase the molecular weight of linear chains of star/linear mixtures the miscibility decreases. Our findings are compared with recent analytical and experimental results.

  15. A Swarm of Ancient Stars

    Science.gov (United States)

    2010-12-01

    to the spectroscopic study of densely populated stellar fields, such as globular clusters. M107 is not visible to the naked eye, but, with an apparent magnitude of about eight, it can easily be observed from a dark site with binoculars or a small telescope. The globular cluster is about 13 arcminutes across, which corresponds to about 80 light-years at its distance, and it is found in the constellation of Ophiuchus, north of the pincers of Scorpius. Roughly half of the Milky Way's known globular clusters are actually found in the constellations of Sagittarius, Scorpius and Ophiuchus, in the general direction of the centre of the Milky Way. This is because they are all in elongated orbits around the central region and are on average most likely to be seen in this direction. Messier 107 was discovered by Pierre Méchain in April 1782 and it was added to the list of seven Additional Messier Objects that were originally not included in the final version of Messier's catalogue, which was published the previous year. On 12 May 1793, it was independently rediscovered by William Herschel, who was able to resolve this globular cluster into stars for the first time. But it was not until 1947 that this globular cluster finally took its place in Messier's catalogue as M107, making it the most recent star cluster to be added to this famous list. This image is composed from exposures taken through the blue, green and near-infrared filters by the Wide Field Camera (WFI) on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile. Notes [1] Fibre Large Array Multi-Element Spectrograph More information ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe and the world's most productive astronomical observatory. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an

  16. Star Cluster Structure from Hierarchical Star Formation

    Science.gov (United States)

    Grudic, Michael; Hopkins, Philip; Murray, Norman; Lamberts, Astrid; Guszejnov, David; Schmitz, Denise; Boylan-Kolchin, Michael

    2018-01-01

    Young massive star clusters (YMCs) spanning 104-108 M⊙ in mass generally have similar radial surface density profiles, with an outer power-law index typically between -2 and -3. This similarity suggests that they are shaped by scale-free physics at formation. Recent multi-physics MHD simulations of YMC formation have also produced populations of YMCs with this type of surface density profile, allowing us to narrow down the physics necessary to form a YMC with properties as observed. We show that the shallow density profiles of YMCs are a natural result of phase-space mixing that occurs as they assemble from the clumpy, hierarchically-clustered configuration imprinted by the star formation process. We develop physical intuition for this process via analytic arguments and collisionless N-body experiments, elucidating the connection between star formation physics and star cluster structure. This has implications for the early-time structure and evolution of proto-globular clusters, and prospects for simulating their formation in the FIRE cosmological zoom-in simulations.

  17. A Wi-Fi Union Mechanism for Internet Advertising Reciprocal Platform in Microenterprises

    Directory of Open Access Journals (Sweden)

    Thi Thanh An Nguyen

    2017-07-01

    Full Text Available With the evolution of the Internet and smartphone devices, Internet advertising has become one of the most important methods for delivering promotional marketing messages to customers. However, the efficiency of Internet advertising for microenterprise is not very high, since Wi-Fi advertising—which is limited by a small router coverage area—is mainly used. Moreover, because of the lack of money, microenterprises have been using low-cost methods to promote their products. Thus, enhancing the effectiveness of Wi-Fi advertising, and solving the problem of cost and the range of the views are now an essential investigation in this study. In this paper, we propose a reciprocal model with Wi-Fi union mechanism for Internet advertising based on fog computing architecture to enhance the efficiency of advertisement, reduce the cost, and increase the range of the views for microenterprise by using the Internet. In particular, the system was built in advertisers’, publishers’, and consumers’ sides. In our system, we use contribution point (CP as an exchange value among the participants. Advertisers and publishers can get CP by helping the others in the system to promote their advertisements, increasing their CP by one unit. Similarly, advertisers and publishers can use their CP to ask for assistance from the others, decreasing their CP by one unit. The result shows that the system in a Wi-Fi union is easy to use, and advertisements can be seen by all customers who are using free Wi-Fi from the stores of the union. This method can solve the problem of cost and fixed consumer groups.

  18. Fusion of Location Fingerprinting and Trilateration Based on the Example of Differential Wi-Fi Positioning

    Science.gov (United States)

    Retscher, G.

    2017-09-01

    Positioning of mobile users in indoor environments with Wireless Fidelity (Wi-Fi) has become very popular whereby location fingerprinting and trilateration are the most commonly employed methods. In both the received signal strength (RSS) of the surrounding access points (APs) are scanned and used to estimate the user's position. Within the scope of this study the advantageous qualities of both methods are identified and selected to benefit their combination. By a fusion of these technologies a higher performance for Wi-Fi positioning is achievable. For that purpose, a novel approach based on the well-known Differential GPS (DGPS) principle of operation is developed and applied. This approach for user localization and tracking is termed Differential Wi-Fi (DWi-Fi) by analogy with DGPS. From reference stations deployed in the area of interest differential measurement corrections are derived and applied at the mobile user side. Hence, range or coordinate corrections can be estimated from a network of reference station observations as it is done in common CORS GNSS networks. A low-cost realization with Raspberry Pi units is employed for these reference stations. These units serve at the same time as APs broadcasting Wi-Fi signals as well as reference stations scanning the receivable Wi-Fi signals of the surrounding APs. As the RSS measurements are carried out continuously at the reference stations dynamically changing maps of RSS distributions, so-called radio maps, are derived. Similar as in location fingerprinting this radio maps represent the RSS fingerprints at certain locations. From the areal modelling of the correction parameters in combination with the dynamically updated radio maps the location of the user can be estimated in real-time. The novel approach is presented and its performance demonstrated in this paper.

  19. Queuing Time Prediction Using WiFi Positioning Data in an Indoor Scenario.

    Science.gov (United States)

    Shu, Hua; Song, Ci; Pei, Tao; Xu, Lianming; Ou, Yang; Zhang, Libin; Li, Tao

    2016-11-22

    Queuing is common in urban public places. Automatically monitoring and predicting queuing time can not only help individuals to reduce their wait time and alleviate anxiety but also help managers to allocate resources more efficiently and enhance their ability to address emergencies. This paper proposes a novel method to estimate and predict queuing time in indoor environments based on WiFi positioning data. First, we use a series of parameters to identify the trajectories that can be used as representatives of queuing time. Next, we divide the day into equal time slices and estimate individuals' average queuing time during specific time slices. Finally, we build a nonstandard autoregressive (NAR) model trained using the previous day's WiFi estimation results and actual queuing time to predict the queuing time in the upcoming time slice. A case study comparing two other time series analysis models shows that the NAR model has better precision. Random topological errors caused by the drift phenomenon of WiFi positioning technology (locations determined by a WiFi positioning system may drift accidently) and systematic topological errors caused by the positioning system are the main factors that affect the estimation precision. Therefore, we optimize the deployment strategy during the positioning system deployment phase and propose a drift ratio parameter pertaining to the trajectory screening phase to alleviate the impact of topological errors and improve estimates. The WiFi positioning data from an eight-day case study conducted at the T3-C entrance of Beijing Capital International Airport show that the mean absolute estimation error is 147 s, which is approximately 26.92% of the actual queuing time. For predictions using the NAR model, the proportion is approximately 27.49%. The theoretical predictions and the empirical case study indicate that the NAR model is an effective method to estimate and predict queuing time in indoor public areas.

  20. A Wi-Fi Union Mechanism for Internet Advertising Reciprocal Platform in Microenterprises.

    Science.gov (United States)

    Nguyen, Thi Thanh An; Chang, Che-Pin; Yuan, Shyan-Ming

    2017-07-13

    With the evolution of the Internet and smartphone devices, Internet advertising has become one of the most important methods for delivering promotional marketing messages to customers. However, the efficiency of Internet advertising for microenterprise is not very high, since Wi-Fi advertising-which is limited by a small router coverage area-is mainly used. Moreover, because of the lack of money, microenterprises have been using low-cost methods to promote their products. Thus, enhancing the effectiveness of Wi-Fi advertising, and solving the problem of cost and the range of the views are now an essential investigation in this study. In this paper, we propose a reciprocal model with Wi-Fi union mechanism for Internet advertising based on fog computing architecture to enhance the efficiency of advertisement, reduce the cost, and increase the range of the views for microenterprise by using the Internet. In particular, the system was built in advertisers', publishers', and consumers' sides. In our system, we use contribution point (CP) as an exchange value among the participants. Advertisers and publishers can get CP by helping the others in the system to promote their advertisements, increasing their CP by one unit. Similarly, advertisers and publishers can use their CP to ask for assistance from the others, decreasing their CP by one unit. The result shows that the system in a Wi-Fi union is easy to use, and advertisements can be seen by all customers who are using free Wi-Fi from the stores of the union. This method can solve the problem of cost and fixed consumer groups.

  1. Space Radar Image of Star City, Russia

    Science.gov (United States)

    1994-01-01

    This radar image shows the Star City cosmonaut training center, east of Moscow, Russia. Four American astronauts are training here for future long-duration flights aboard the Russian Mir space station. These joint flights are giving NASA and the Russian Space Agency experience necessary for the construction of the international Alpha space station, beginning in late 1997. This image was acquired by the Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR), on its 62nd orbit on October 3, 1994. This Star City image is centered at 55.55 degrees north latitude and 38.0 degrees east longitude. The area shown is approximately 32 kilometers by 49 kilometers (20 miles by 30 miles). North is to the top in this image. The radar illumination is from the top of the image. The image was produced using three channels of SIR-C radar data: red indicates L-band (23 cm wavelength, horizontally transmitted and received); green indicates L-band (horizontally transmitted and vertically received); blue indicates C-band (6 cm wavelength, horizontally transmitted and vertically received). In general, dark pink areas are agricultural; pink and light blue areas are urban communities; black areas represent lakes and rivers; dark blue areas are cleared forest; and light green areas are forested. The prominent black runways just right of center are Shchelkovo Airfield, about 4 km long. The textured pale blue-green area east and southeast of Shchelkovo Airfield is forest. Just east of the runways is a thin railroad line running southeast; the Star City compound lies just east of the small bend in the rail line. Star City contains the living quarters and training facilities for Russian cosmonauts and their families. Moscow's inner loop road is visible at the lower left edge of the image. The Kremlin is just off the left edge, on the banks of the meandering Moskva River. The Klyazma River snakes to the southeast from the reservoir in the upper left (shown in bright red

  2. Dense Axion Stars.

    Science.gov (United States)

    Braaten, Eric; Mohapatra, Abhishek; Zhang, Hong

    2016-09-16

    If the dark matter particles are axions, gravity can cause them to coalesce into axion stars, which are stable gravitationally bound systems of axions. In the previously known solutions for axion stars, gravity and the attractive force between pairs of axions are balanced by the kinetic pressure. The mass of these dilute axion stars cannot exceed a critical mass, which is about 10^{-14}M_{⊙} if the axion mass is 10^{-4}  eV. We study axion stars using a simple approximation to the effective potential of the nonrelativistic effective field theory for axions. We find a new branch of dense axion stars in which gravity is balanced by the mean-field pressure of the axion Bose-Einstein condensate. The mass on this branch ranges from about 10^{-20}M_{⊙} to about M_{⊙}. If a dilute axion star with the critical mass accretes additional axions and collapses, it could produce a bosenova, leaving a dense axion star as the remnant.

  3. Functional significance of protein assemblies predicted by the crystal structure of the restriction endonuclease BsaWI.

    Science.gov (United States)

    Tamulaitis, Gintautas; Rutkauskas, Marius; Zaremba, Mindaugas; Grazulis, Saulius; Tamulaitiene, Giedre; Siksnys, Virginijus

    2015-09-18

    Type II restriction endonuclease BsaWI recognizes a degenerated sequence 5'-W/CCGGW-3' (W stands for A or T, '/' denotes the cleavage site). It belongs to a large family of restriction enzymes that contain a conserved CCGG tetranucleotide in their target sites. These enzymes are arranged as dimers or tetramers, and require binding of one, two or three DNA targets for their optimal catalytic activity. Here, we present a crystal structure and biochemical characterization of the restriction endonuclease BsaWI. BsaWI is arranged as an 'open' configuration dimer and binds a single DNA copy through a minor groove contacts. In the crystal primary BsaWI dimers form an indefinite linear chain via the C-terminal domain contacts implying possible higher order aggregates. We show that in solution BsaWI protein exists in a dimer-tetramer-oligomer equilibrium, but in the presence of specific DNA forms a tetramer bound to two target sites. Site-directed mutagenesis and kinetic experiments show that BsaWI is active as a tetramer and requires two target sites for optimal activity. We propose BsaWI mechanism that shares common features both with dimeric Ecl18kI/SgrAI and bona fide tetrameric NgoMIV/SfiI enzymes. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  4. Entropy Production of Stars

    Directory of Open Access Journals (Sweden)

    Leonid M. Martyushev

    2015-06-01

    Full Text Available The entropy production (inside the volume bounded by a photosphere of main-sequence stars, subgiants, giants, and supergiants is calculated based on B–V photometry data. A non-linear inverse relationship of thermodynamic fluxes and forces as well as an almost constant specific (per volume entropy production of main-sequence stars (for 95% of stars, this quantity lies within 0.5 to 2.2 of the corresponding solar magnitude is found. The obtained results are discussed from the perspective of known extreme principles related to entropy production.

  5. Infrared spectroscopy of stars

    Science.gov (United States)

    Merrill, K. M.; Ridgway, S. T.

    1979-01-01

    This paper reviews applications of IR techniques in stellar classification, studies of stellar photospheres, elemental and isotopic abundances, and the nature of remnant and ejected matter in near-circumstellar regions. Qualitative IR spectral classification of cool and hot stars is discussed, along with IR spectra of peculiar composite star systems and of obscured stars, and IR characteristics of stellar populations. The use of IR spectroscopy in theoretical modeling of stellar atmospheres is examined, IR indicators of stellar atmospheric composition are described, and contributions of IR spectroscopy to the study of stellar recycling of interstellar matter are summarized. The future of IR astronomy is also considered.

  6. Nuclear physics of stars

    CERN Document Server

    Iliadis, Christian

    2007-01-01

    Thermonuclear reactions in stars is a major topic in the field of nuclear astrophysics, and deals with the topics of how precisely stars generate their energy through nuclear reactions, and how these nuclear reactions create the elements the stars, planets and - ultimately - we humans consist of. The present book treats these topics in detail. It also presents the nuclear reaction and structure theory, thermonuclear reaction rate formalism and stellar nucleosynthesis. The topics are discussed in a coherent way, enabling the reader to grasp their interconnections intuitively. The book serves bo

  7. SeaWiFS technical report series. Volume 26: Results of the SeaWiFS Data Analysis Round-Robin, July 1994 (DARR-1994)

    Science.gov (United States)

    Hooker, Stanford B. (Editor); Firestone, Elaine R. (Editor); Siegel, David A.; Obrien, Margaret C.; Sorensen, Jen C.; Konnoff, Daniel A.; Brody, Eric A.; Mueller, James L.; Davis, Curtiss O.; Rhea, W. Joseph

    1995-01-01

    The accurate determination of upper ocean apparent optical properties (AOP's) is essential for the vicarious calibration of the sea-viewing wide field-of-view sensor (SeaWiFS) instrument and the validation of the derived data products. To evaluate the role that data analysis methods have upon values of derived AOP's, the first Data Analysis Round-Robin (DARR-94) workshop was sponsored by the SeaWiFS Project during 21-23 July, 1994. The focus of this intercomparison study was the estimation of the downwelling irradiance spectrum just beneath the sea surface, E(sub d)(0(sup -), lambda); the upwelling nadir radiance just beneath the sea surface, L(sub u)(0(sup -), lambda); and the vertical profile of the diffuse attenuation coefficient spectrum, K(sub d)(z, lambda). In the results reported here, different methodologies from four research groups were applied to an identical set of 10 spectroradiometry casts in order to evaluate the degree to which data analysis methods influence AOP estimation, and whether any general improvements can be made. The overall results of DARR-94 are presented in Chapter 1 and the individual methods of the four groups are presented in Chapters 2-5. The DARR-94 results do not show a clear winner among data analysis methods evaluated. It is apparent, however, that some degree of outlier rejection is required in order to accurately estimate L(sub u)(0(sup -), lambda) or E(sub d)(0(sup -), lambda). Furthermore, the calculation, evaluation and exploitation of confidence intervals for the AOP determinations needs to be explored. That is, the SeaWiFS calibration and validation problem should be recast in statistical terms where the in situ AOP values are statistical estimates with known confidence intervals.

  8. Service Level Agreement for the QoS Guaranteed Mobile IPTV Services over Mobile WiMAX Networks

    OpenAIRE

    Chowdhury, Mostafa Zaman; Trung, Bui Minh; Jang, Yeong Min; Kim, Young-Il; Ryu, Won

    2011-01-01

    While mobile IPTV services are supported through the mobile WiMAX networks, there must need some guaranteed bandwidth for the IPTV services especially if IPTV and non-IPTV services are simultaneously supported by the mobile WiMAX networks. The quality of an IPTV service definitely depends on the allocated bandwidth for that channel. However, due to the high quality IPTV services and to support of huge non-IPTV traffic over mobile WiMAX networks, it is not possible to guarantee the sufficient ...

  9. Portal Website Analysis Using ISO / IEC 9126-4 Metric Effectiveness (Case Study Indonesia Wi-Fi Portal Website)

    OpenAIRE

    Jumrotuhuda, Refky

    2014-01-01

    According to the increasing of human necessity, Development of technology have to bring the same increasing in order to support and facilitate every activity in all sorts of the human life. Internet is the one of the real outcome from the development of technology. Indonesia Wi-Fi is a public internet network server based on Wi-Fi/Hotspot technology developed by TELKOM Group and other related operator to the TELKOM enterprise. Portal website of Indonesia Wi-Fi is used as a portal for user to ...

  10. Wifi, WiMax and LTE multi-hop mesh networks basic communication protocols and application areas

    CERN Document Server

    Wei, Hung-Yu; Dixit, Sudhir

    2013-01-01

    Wifi, WiMAX, and Cellular Multihop Networks presents an overview of WiFi-based and WiMAX-based multihop relay networks. As the first text to cover IEEE 802.16j multihop hop relay technology, this revolutionary resource explores the latest advances in multi-hop and ad-hoc networking. Not only does this reference provide the technological aspects, but also the applications for the emerging technology and architectural issues. Ranging from introductory material to advanced topics, this guidebook, plus PowerPoint slides, is essential for engineers, researchers, and students interested in

  11. Carbon Stars T. Lloyd Evans

    Indian Academy of Sciences (India)

    that the features used in estimating luminosities of ordinary giant stars are just those whose abundance ... This difference between the spectral energy distributions (SEDs) of CH stars and the. J stars, which belong to .... that the first group was binaries, as for the CH stars of the solar vicinity, while those of the second group ...

  12. Neutron Stars : Magnetism vs Gravity

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Neutron Stars : Magnetism vs Gravity. WHY do neutron stars have such strong magnetic fields? Conservation of magnetic flux of the collapsing stellar core. ∫ B.ds (over surface of the star) = constant; Radius of the star collapses from ~ 5x108 to 1x104 metres; Hence, ...

  13. Observational Effects of Strange Stars

    OpenAIRE

    Lu, T.

    1998-01-01

    In this talk, after briefly reviewing some historical remarks concerning strange stars, the achievements in physics and dynamical behavior of strange stars are discussed. Especially, various observational effects in distinguishing strange stars from neutron stars such as mechanical effects, cooling effects, phase transition and related interesting phenomena are stressed.

  14. Northern star js plaskett

    CERN Document Server

    Broughton, R Peter

    2018-01-01

    Northern Star explores Plaskett's unorthodox and fascinating life from his rural roots near Woodstock through his days as a technician at the University of Toronto to his initiation in astronomy at the Dominion Observatory in Ottawa.

  15. SX Phoenicis stars

    International Nuclear Information System (INIS)

    Nemec, J.; Mateo, M.

    1990-01-01

    The purpose of this paper is to review the basic observational information concerning SX Phe stars, including recent findings such as the discovery of about 40 low-luminosity variable stars in the Carina dwarf galaxy and identification of at least one SX Phe star in the metal-rich globular cluster M71. Direct evidence supporting the hypothesis that at least some BSs are binary systems comes from the discovery of two contact binaries and a semidetached binary among the 50 BSs in the globular cluster NGC 5466. Since these systems will coalesce on a time scale 500 Myr, it stands to reason that many (if not most) BSs are coalesced binaries. The merger hypothesis also explains the relatively-large masses (1.0-1.2 solar masses) that have been derived for SX Phe stars and halo BSs, and may also account for the nonvariable BSs in the 'SX Phe instability strip'. 132 refs

  16. Planets Around Neutron Stars

    Science.gov (United States)

    Wolszczan, Alexander; Kulkarni, Shrinivas R; Anderson, Stuart B.

    2003-01-01

    The objective of this proposal was to continue investigations of neutron star planetary systems in an effort to describe and understand their origin, orbital dynamics, basic physical properties and their relationship to planets around normal stars. This research represents an important element of the process of constraining the physics of planet formation around various types of stars. The research goals of this project included long-term timing measurements of the planets pulsar, PSR B1257+12, to search for more planets around it and to study the dynamics of the whole system, and sensitive searches for millisecond pulsars to detect further examples of old, rapidly spinning neutron stars with planetary systems. The instrumentation used in our project included the 305-m Arecibo antenna with the Penn State Pulsar Machine (PSPM), the 100-m Green Bank Telescope with the Berkeley- Caltech Pulsar Machine (BCPM), and the 100-m Effelsberg and 64-m Parkes telescopes equipped with the observatory supplied backend hardware.

  17. Principles of star formation

    CERN Document Server

    Bodenheimer, Peter H

    2011-01-01

    Understanding star formation is one of the key fields in present-day astrophysics. This book treats a wide variety of the physical processes involved, as well as the main observational discoveries, with key points being discussed in detail. The current star formation in our galaxy is emphasized, because the most detailed observations are available for this case. The book presents a comparison of the various scenarios for star formation, discusses the basic physics underlying each one, and follows in detail the history of a star from its initial state in the interstellar gas to its becoming a condensed object in equilibrium. Both theoretical and observational evidence to support the validity of the general evolutionary path are presented, and methods for comparing the two are emphasized. The author is a recognized expert in calculations of the evolution of protostars, the structure and evolution of disks, and stellar evolution in general. This book will be of value to graduate students in astronomy and astroph...

  18. Effects of electromagnetic waves emitted from 3G+wi-fi modems on human semen analysis.

    Science.gov (United States)

    Kamali, Koosha; Atarod, Mohammadmehdi; Sarhadi, Saeedeh; Nikbakht, Javad; Emami, Maryam; Maghsoudi, Robab; Salimi, Hormoz; Fallahpour, Bita; Kamali, Negar; Momtazan, Abdolreza; Ameli, Mojtaba

    2017-10-25

    The purpose of this study was to evaluate the effects of 3G+wifi modems on human sperm quality.A total of 40 semen specimens were gathered between March and September 2015, from healthy adult men. The sperm samples were divided into two groups - 3G+wi-fi exposed and unexposed groups. In the unexposed group, the specimens were shielded by aluminum foil in three layers and put into an incubator at a temperature of 37°C for 50 minutes. The exposed group was positioned in another room in an incubator at a temperature of 37°C for 50 minutes. A 3G+wi-fi modem was put into the same incubator and a laptop computer was connected to the modem and was downloading for the entire 50 minutes.Semen analysis was done for each specimen and comparisons between parameters of the two groups were done by using Kolmogorov-Smirnov study and a paired t-test. Mean percentage of sperm with class A and B motility were not significantly different in two groups (p = 0.22 and 0.54, respectively). In class C, it was significantly lower in the exposed group (p = 0.046), while in class D it was significantly higher (p = 0.022).Velocity curvilinear, velocity straight line, velocity average path, mean angular displacement, lateral displacement and beat cross frequency were significantly higher in the unexposed group. The limitation was the in vitro design. Electromagnetic waves (EMWs) emitted from 3G+wi-fi modems cause a significant decrease in sperm motility and velocity, especially in non-progressive motile sperms. Other parameters of semen analysis did not change significantly.EMWs, which are used in communications worldwide, are a suspected cause of male infertility. Many studies evaluated the effects of cell phones and wi-fi on fertility. To our knowledge, no study has yet been done to show the effects of EMWs emitted from 3G+wi-fi modems on fertility.Our study revealed a significant decrease in the quality of human semen after exposure to EMWs emitted from 3G+wi-fi modems.

  19. Recent highlights from STAR

    Science.gov (United States)

    Zha, Wangmei

    2018-02-01

    The Solenoidal Tracker at RHIC (STAR) experiment takes advantage of its excellent tracking and particle identification capabilities at mid-rapidity to explore the properties of strongly interacting QCD matter created in heavy-ion collisions at RHIC. The STAR collaboration presented 7 parallel and 2 plenary talks at Strangeness in Quark Matter 2017 and covered various topics including heavy flavor measurements, bulk observables, electro-magnetic probes and the upgrade program. This paper highlights some of the selected results.

  20. Star of Bethlehem

    Science.gov (United States)

    Hughes, D.; Murdin, P.

    2001-07-01

    The biblical Star of Bethlehem, which heralded the birth of Jesus Christ, is only mentioned in the Gospel of St Matthew 2. The astrologically significant 7 bc triple conjunction of Jupiter and Saturn in the constellation of Pisces is the most likely candidate, although a comet/nova in 5 bc and a comet in 4 bc cannot be ruled out. There is also the possibility that the star was simply fictitious....

  1. Young Stars with SALT

    Energy Technology Data Exchange (ETDEWEB)

    Riedel, Adric R. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Alam, Munazza K.; Rice, Emily L.; Cruz, Kelle L. [Department of Astrophysics, The American Museum of Natural History, New York, NY 10024 (United States); Henry, Todd J., E-mail: arr@caltech.edu [RECONS Institute, Chambersburg, PA (United States)

    2017-05-10

    We present a spectroscopic and kinematic analysis of 79 nearby M dwarfs in 77 systems. All of these dwarfs are low-proper-motion southern hemisphere objects and were identified in a nearby star survey with a demonstrated sensitivity to young stars. Using low-resolution optical spectroscopy from the Red Side Spectrograph on the South African Large Telescope, we have determined radial velocities, H-alpha, lithium 6708 Å, and potassium 7699 Å equivalent widths linked to age and activity, and spectral types for all of our targets. Combined with astrometric information from literature sources, we identify 44 young stars. Eighteen are previously known members of moving groups within 100 pc of the Sun. Twelve are new members, including one member of the TW Hydra moving group, one member of the 32 Orionis moving group, 9 members of Tucana-Horologium, one member of Argus, and two new members of AB Doradus. We also find 14 young star systems that are not members of any known groups. The remaining 33 star systems do not appear to be young. This appears to be evidence of a new population of nearby young stars not related to the known nearby young moving groups.

  2. Young Stars with SALT

    Science.gov (United States)

    Riedel, Adric R.; Alam, Munazza K.; Rice, Emily L.; Cruz, Kelle L.; Henry, Todd J.

    2017-05-01

    We present a spectroscopic and kinematic analysis of 79 nearby M dwarfs in 77 systems. All of these dwarfs are low-proper-motion southern hemisphere objects and were identified in a nearby star survey with a demonstrated sensitivity to young stars. Using low-resolution optical spectroscopy from the Red Side Spectrograph on the South African Large Telescope, we have determined radial velocities, H-alpha, lithium 6708 Å, and potassium 7699 Å equivalent widths linked to age and activity, and spectral types for all of our targets. Combined with astrometric information from literature sources, we identify 44 young stars. Eighteen are previously known members of moving groups within 100 pc of the Sun. Twelve are new members, including one member of the TW Hydra moving group, one member of the 32 Orionis moving group, 9 members of Tucana-Horologium, one member of Argus, and two new members of AB Doradus. We also find 14 young star systems that are not members of any known groups. The remaining 33 star systems do not appear to be young. This appears to be evidence of a new population of nearby young stars not related to the known nearby young moving groups. Based on observations made with the Southern African Large Telescope (SALT).

  3. Massive star evolution

    International Nuclear Information System (INIS)

    Varshavskij, V.I.; Tutukov, A.V.; AN SSSR, Moscow. Astronomicheskij Sovet)

    1975-01-01

    The structure and evolution of 16 (Sun mass), 32 (Sun mass), and 64 (Sun mass) stars with the initial chemical composition X=0.602, Y=0.354, and Z=0.044 (X 12 = 0.00619 and X 16 = 0.01847) are analyzed from the initial main sequence to a complete burnup of oxygen in the nucleus of a red supergiant. At the stage of helium buring in the nucleus the evolutionary track of the star is determined by the equilibrium condition in the zone of varying chemical composition, and at later stages by energy losses due to neutrino emission. In the absence of neutrino emission the external convective zone propagates into regions occupied by the former hydrogen and helium layer sources. This may lead to considerable anomalies in the chemical composition at the star surface and to the decrease of the carbon-oxygen nucleus mass. With regard to neutrino energy losses the structure of layer sources and of the star itself becomes more complicated, thereby increasing the evolution time. Estimation is made of the change in heli.um, carbon, and oxygen contents in the interstellar space over the Galaxy's lifetime as a result of the evolution of massive stars. Some consequences of rotation and meridional circulations are discussed. A study of the structure and evolution of hydrogen-helium massive stars before firing of carbon in the nucleus is made

  4. Collapsing Enormous Stars

    Science.gov (United States)

    Kohler, Susanna

    2015-09-01

    One of the big puzzles in astrophysics is how supermassive black holes (SMBHs) managed to grow to the large sizes weve observed in the very early universe. In a recent study, a team of researchers examines the possibility that they were formed by the direct collapse of supermassive stars.Formation MysterySMBHs billions of times as massive as the Sun have been observed at a time when the universe was less than a billion years old. But thats not enough time for a stellar-mass black hole to grow to SMBH-size by accreting material so another theory is needed to explain the presence of these monsters so early in the universes history. A new study, led by Tatsuya Matsumoto (Kyoto University, Japan), poses the following question: what if supermassive stars in the early universe collapsed directly into black holes?Previous studies of star formation in the early universe have suggested that, in the hot environment of these primordial times, stars might have been able to build up mass much faster than they can today. This could result in early supermassive stars roughly 100,000 times more massive than the Sun. But if these early stars end their lives by collapsing to become massive black holes in the same way that we believe massive stars can collapse to form stellar-mass black holes today this should result in enormously violent explosions. Matusmoto and collaborators set out to model this process, to determine what we would expect to see when it happens!Energetic BurstsThe authors modeled the supermassive stars prior to collapse and then calculated whether a jet, created as the black hole grows at the center of the collapsing star, would be able to punch out of the stellar envelope. They demonstrated that the process would work much like the widely-accepted collapsar model of massive-star death, in which a jet successfully punches out of a collapsing star, violently releasing energy in the form of a long gamma-ray burst (GRB).Because the length of a long GRB is thought to

  5. Harbour seals (Phoca vitulina) can steer by the stars.

    Science.gov (United States)

    Mauck, Björn; Gläser, Nele; Schlosser, Wolfhard; Dehnhardt, Guido

    2008-10-01

    Offshore orientation in marine mammals is still a mystery. For visual orientation during night-time foraging and travelling in the open seas, seals cannot rely on distant terrestrial landmarks, and thus might use celestial cues as repeatedly shown for nocturnally migrating birds. Although seals detect enough stars to probably allow for astronavigation, it was unclear whether they can orient by the night sky. The widely accepted cognitive mechanism for bird night-time orientation by celestial cues is a time-independent star compass with learned geometrical star configurations used to pinpoint north as the rotational centre of the starry sky while there is no conclusive evidence for a time-compensated star compass or true star navigation. Here, we present results for two harbour seals orienting in a custom made swimming planetarium. Both seals learned to highly accurately identify a lodestar out of a pseudo-randomly oriented, realistic projection of the northern hemisphere night sky. Providing the first evidence for star orientation capability in a marine mammal, our seals' outstanding directional precision would allow them to steer by following lodestars of learned star courses, a celestial orientation mechanism that has been known to be used by Polynesian navigators but has not been considered for animals yet.

  6. Analisis Kinerja Subscriber Station WiMAX di Urban Area Bandung

    Directory of Open Access Journals (Sweden)

    DWI ARYANTA

    2017-06-01

    Full Text Available ABSTRAK   Teknologi komunikasi wireless semakin pesat mengalami perkembangan. WiMAX  merupakan suatu teknologi broadband yang didukung oleh standar IEEE 802.16d (802.16-2004 yang mampu memberikan layanan data berkecepatan tinggi hingga 75 Mbps dalam radius maksimal 40-50 km pada bandwidth 20 MHz. Alokasi frekuensi yang dipakai Indonesia untuk jaringan WiMAX  ini ialah 3,3 – 3,4 GHz. Penelitian ini dilakukan dengan melakukan proses pengukuran kinerja perangkat radio WiMAX  yaitu HiMax 331-SS. Proses pengukuran dilakukan antara CPE dan base station dengan antenna sektoral 1200 pada ketinggian 45 m. Lokasi pengukuran dilakukan di beberapa area kota Bandung yang telah ditentukan sebelumnya. Hasil pengukuran memperlihatkan nilai CINR tertinggi adalah 31 dB dengan modulasi 64 QAM – ¾ dan terendah nilai 10 dB dengan modulasi BPSK 1/2. Nilai RSSI tertinggi -54 dBm berada dan nilai RSSI terendah -89 dBm. Nilai throughput tertinggi untuk layanan streaming video sebesar  1000,8 kbps (downlink dengan modulasi 64 QAM – ¾. Nilai delay terendah sebesar 56,247 ms pada kondisi LOS dan tertinggi sebesar 139,5 ms pada kondisi NLOS. Nilai terbesar packet loss sebesar 20% yaitu pada lokasi pengukuran terjauh 14,3 km. Kata Kunci : delay, packet loss, RSSI, CINR, throughput, CPE, WiMAX .   ABSTRACT   Wireless communication technologies have evolved more rapidly. WiMAX  is a broadband technology that is supported by the IEEE standard 802.16-2004/d which is able to provide high speed data services of up to 75 Mbps within a radius of 40-50 km at a maximum bandwidth of 20 MHz. Indonesia frequency allocation used for the WiMAX  network is 3.3 to 3.4 GHz. This study was conducted with the performance measurement process that is Himax 331 WiMAX  radio - SS. Process measurement is made between the CPE and base station sector antennas at a height of 45 m in 1200. Locations measurements performed in several areas of Bandung predetermined. The measurement

  7. Positioning indoors with Wi-Fi devices of low-cost

    International Nuclear Information System (INIS)

    Moreira, Fabricio M.; Farias, Marcos S.; Carvalho, Paulo Victor R. de

    2017-01-01

    The rhythm of research development linked to location tracking is highly linked with the advancement of wireless sensor network and wireless technologies. A classic example is the Global Positioning System (GPS), where satellites are used to send signals to receivers on earth that use these signals to compute navigation information. However, as communication between the satellites and GPS receivers require radio propagation in line of sight, the GPS system usually only works outdoors. For the growing interest in research to position tracking indoors, you must use wireless devices based on Bluetooth or Wi-Fi technology (IEEE 802.11). The aim of this work is to show the development of applications using new Wi-Fi devices (ESP8266) for the estimation of positioning and location indoors

  8. A Wireless Physiological Signal Monitoring System with Integrated Bluetooth and WiFi Technologies.

    Science.gov (United States)

    Yu, Sung-Nien; Cheng, Jen-Chieh

    2005-01-01

    This paper proposes a wireless patient monitoring system which integrates Bluetooth and WiFi wireless technologies. A wireless portable multi-parameter device was designated to acquire physiological signals and transmit them to a local server via Bluetooth wireless technology. Four kinds of monitor units were designed to communicate via the WiFi wireless technology, including a local monitor unit, a control center, mobile devices (personal digital assistant; PDA), and a web page. The use of various monitor units is intending to meet different medical requirements for different medical personnel. This system was demonstrated to promote the mobility and flexibility for both the patients and the medical personnel, which further improves the quality of health care.

  9. Capacity Evaluation for IEEE 802.16e Mobile WiMAX

    Directory of Open Access Journals (Sweden)

    Chakchai So-In

    2010-01-01

    Full Text Available We present a simple analytical method for capacity evaluation of IEEE 802.16e Mobile WiMAX networks. Various overheads that impact the capacity are explained and methods to reduce these overheads are also presented. The advantage of a simple model is that the effect of each decision and sensitivity to various parameters can be seen easily. We illustrate the model by estimating the capacity for three sample applications—Mobile TV, VoIP, and data. The analysis process helps explain various features of IEEE 802.16e Mobile WiMAX. It is shown that proper use of overhead reducing mechanisms and proper scheduling can make an order of magnitude difference in performance. This capacity evaluation method can also be used for validation of simulation models.

  10. Experience of the WiN Hungary in Communication with Public on a Big Social Events

    International Nuclear Information System (INIS)

    Szucsán, M.

    2015-01-01

    My poster presentation is about a process of communication with public during big social events like festivals, open days and sport’s competitions. The technique is: we make a WiN stand on the frequent place of events, invite visitors and kindly ask them to fill our questionnaire about nuclear industry in Hungary. The questionnaire contents 15 questions about Hungarian NPP (how many units we have, what is electrical output). We communicate with visitors during the filling a questionnaire and after that we check the result. We can see the level of knowledge of our guest and give them the appropriate information on their level. Usually every participant takes a small present with the emblem of WiN Hungary. This form of communication has tested many times in our activity. It works very effectively. The form of poster is a chart flow of the process illustrated with photos. (author)

  11. A WiMAX Networked UAV Telemetry System for Net-Centric Remote Sensing and Range Surveillance, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A WiMAX networked UAV Telemetry System (WNUTS) is designed for net-centric remote sensing and launch range surveillance applications. WNUTS integrates a MIMO powered...

  12. Implementació de càmera Wi-Fi mitjançant dispositiu mòbil

    OpenAIRE

    Simon Bisbal, Jordi Tabaré

    2012-01-01

    Implementació de càmera IP per Wi-Fi mitjançant dispositiu mòbil. [ANGLÈS] IP Camera implementation with Android SDK. It takes the images from the device cam and sends them through the Wi-Fi network using RTP. [CASTELLÀ] Implementación en Android SDK de cámara IP, que envía las imágenes captadas por el móvil a través de la red Wi-Fi mediante RTP. [CATALÀ] Implementació en Android SDK de càmera IP, que envia les imatges captades pel la càmera del mòbil en RTP a través de la xarxa Wi-F...

  13. The Role of the WI-38 Cell Strain in Saving Lives and Reducing Morbidity

    OpenAIRE

    S. J. Olshansky; L. Hayflick

    2017-01-01

    The modern success story of vaccinations involves a historical chain of events that transformed the discovery that vaccines worked, to administering them to the population. We estimate the number of lives saved and morbidity reduction associated with the discovery of the first human cell strain used for the production of licensed human virus vaccines, known as WI-38. The diseases studied include poliomyelitis, measles, mumps, rubella, varicella (chicken pox), herpes zoster, adenovirus, rabies...

  14. WiFi Hot Spot Service Business for the Automotive and Oil Industries: A Competitive Analysis

    Directory of Open Access Journals (Sweden)

    Louis-Francois PAU

    2010-01-01

    Full Text Available While you refuel for gas, why not refuel for information or upload vehicle data, using a cheap wireless technology as WiFi? This paper analyzes in extensive detail the user segmentation by vehicle usage, service offering, and full business models from WiFi hot spot services delivered to and from vehicles (private, professional, public around gas stations. Are also analyzed the parties which play a role in such services: authorization, provisioning and delivery, with all the dependencies modelled by attributed digraphs. Account is made of WiFi base station technical capabilities and costs. Five year financial models (CAPEX, OPEX, and data pertain to two possible service suppliers: multi-service oil companies, and mobile service operators (or MVNOs. Model optimization on the return-on-investment (R.O.I. is carried out for different deployment scenarios, geographical coverage assumptions, as well as tariff structures. Comparison is also being made with public GPRS and 3G data services, as precursors to HSPA/LTE, and the effect of WiFi roaming is analyzed. Regulatory implications, including those dealing with public safety, are addressed. Analysis shows that due to manpower costs and marketing costs, suitable R.O.I. will not be achieved unless externalities are accounted for and innovative tariff structures are introduced. Open issues and further research are outlined. Further work is currently carried out with automotive electronics sector, wireless systems providers, wireless terminals platform suppliers, and vehicle manufacturers. Future relevance of this work is also discussed for the emerging electrical reloading grids for electrical vehicles.

  15. Hybrid RSOA and fibre raman amplified long reach feeder link for WiMAX-on-fibre

    DEFF Research Database (Denmark)

    Amaya Fernández, Ferney Orlando; Martinez, Javier; Yu, Xianbin

    2009-01-01

    A distributed fibre Raman amplified long reach optical access feeder link using a reflective semiconductor optical amplifier in the remote base station is experimentally demonstrated for supporting WiMAXover- fibre transmission. The measured values for the error vector magnitude for quadrature ph...... phase shift keying and 16-ary quadrature amplitude modulation after 40 km of fibre transmission meet the IEEE 820.16 standard requirements...

  16. Performance Analysis of VoIP Codecs over WiMAX Networks

    OpenAIRE

    M.A. Mohamed; F.W. Zaki; A.M. Elfeki

    2012-01-01

    Real-time services such as VoIP are becoming popular and are major revenue earners for network service providers. These services no longer confined to the wired domain and extended over wireless networks. Although some of the existing wireless technologies can support some low-band width applications, the bandwidth demands of many multimedia applications exceed the capacity of these technologies. The WiMAX promises to be one of the wireless access technologies capable of supporting very high ...

  17. A Wi-Fi Union Mechanism for Internet Advertising Reciprocal Platform in Microenterprises

    OpenAIRE

    Thi Thanh An Nguyen; Che-Pin Chang; Shyan-Ming Yuan

    2017-01-01

    With the evolution of the Internet and smartphone devices, Internet advertising has become one of the most important methods for delivering promotional marketing messages to customers. However, the efficiency of Internet advertising for microenterprise is not very high, since Wi-Fi advertising?which is limited by a small router coverage area?is mainly used. Moreover, because of the lack of money, microenterprises have been using low-cost methods to promote their products. Thus, enhancing the ...

  18. RF Exposure Analysis for Multiple Wi-Fi Devices In Enclosed Environment

    Science.gov (United States)

    Hwu, Shian U.; Rhodes, Bryan A.; deSilva, B. Kanishka; Sham, Catherine C.; Keiser, James R.

    2013-01-01

    Wi-Fi devices operated inside a metallic enclosure have been investigation in the recent years. A motivation for this study is to investigate wave propagation inside an enclosed environment such as elevator, car, aircraft, and spacecraft. There are performances and safety concerned that when the RF transmitters are used in the metallic enclosed environments. In this paper, the field distributions inside a confined room were investigated with multiple portable Wi-Fi devices. Computer simulations were performed using the rigorous computational electromagnetics (CEM). The method of moments (MoM) was used to model the mutual coupling among antennas. The geometrical theory of diffraction (GTD) was applied for the multiple reflections off the ground and walls. The prediction of the field distribution inside such environment is useful for the planning and deployment of a wireless radio and sensor system. Factors that affect the field strengths and distributions of radio waves in confined space were analyzed. The results could be used to evaluate the RF exposure safety in confined environment. By comparing the field distributions for various scenarios, it was observed that the Wi-Fi device counts, spacing and relative locations in the room are important factors in such environments. The RF Keep Out Zone (KOZ), where the electric field strengths exceed the permissible RF exposure limit, could be used to assess the RF human exposure compliance. As shown in this study, it s possible to maximize or minimize field intensity in specific area by arranging the Wi-Fi devices as a function of the relative location and spacing in a calculated manner.

  19. Effect of in utero wi-fi exposure on the pre- and postnatal development of rats.

    Science.gov (United States)

    Poulletier de Gannes, Florence; Haro, Emmanuelle; Hurtier, Annabelle; Taxile, Murielle; Athane, Axel; Ait-Aissa, Saliha; Masuda, Hiroshi; Percherncier, Yann; Ruffié, Gilles; Billaudel, Bernard; Dufour, Philippe; Veyret, Bernard; Lagroye, Isabelle

    2012-04-01

    The increase in exposure to the Wireless Fidelity (Wi-Fi) wireless communication signal has raised public health concerns especially for young people. Animal studies looking at the effects of early life and prenatal exposure to this source of electromagnetic fields, in the radiofrequency (RF) range, on development and behavior have been considered as high priority research needs by the World Health Organization. For the first time, our study assessed the effects of in utero exposure to a 2450 MHz Wi-Fi signal (2 hr/day, 6 days/week for 18 days) on pregnant rats and their pups. Three levels in terms of whole-body specific absorption rate were used: 0.08, 0.4, and 4 W/kg. The prenatal study on fetuses delivered by caesarean (P20) concerned five females/group. The dams and their offspring were observed for 28 days after delivery (15 females/group). For all test conditions, no abnormalities were noted in the pregnant rats and no significant signs of toxicity were observed in the pre- and postnatal development of the pups, even at the highest level of 4 W/kg. In the present study, no teratogenic effect of repeated exposures to the Wi-Fi wireless communication signal was demonstrated even at the highest level of 4 W/kg. The results from this screening study aimed at investigating Wi-Fi effects, strengthen the previous conclusions that teratology and development studies have not detected any noxious effects of exposures to mobile telephony-related RF fields at exposure levels below standard limits. © 2012 Wiley Periodicals, Inc.

  20. Design and Development of Basic Physical Layer WiMAX Network Simulation Models

    Science.gov (United States)

    2009-01-01

    Wide Web . The third software version was developed during the period of 22 August to 4 November, 2008. The software version developed during the...researched on the Web . The mathematics of some fundamental concepts such as Fourier transforms, convolutional coding techniques were also reviewed...Mathworks Matlab users’ website. A simulation model was found, entitled Estudio y Simulacion de la capa Jisica de la norma 802.16 ( Sistema WiMAX) developed

  1. Regional to Global Assessments of Phytoplankton Dynamics From The SeaWiFS Mission

    Science.gov (United States)

    Siegel, David; Behrenfeld, Michael; Maritorena, Stephanie; McClain, Charles R.; Antoine, David; Bailey, Sean W.; Bontempi, Paula S.; Boss, Emmanuel S.; Dierssen, Heidi M.; Doney, Scott C.; hide

    2013-01-01

    Photosynthetic production of organic matter by microscopic oceanic phytoplankton fuels ocean ecosystems and contributes roughly half of the Earth's net primary production. For 13 years, the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) mission provided the first consistent, synoptic observations of global ocean ecosystems. Changes in the surface chlorophyll concentration, the primary biological property retrieved from SeaWiFS, have traditionally been used as a metric for phytoplankton abundance and its distribution largely reflects patterns in vertical nutrient transport. On regional to global scales, chlorophyll concentrations covary with sea surface temperature (SST) because SST changes reflect light and nutrient conditions. However, the oceanmay be too complex to be well characterized using a single index such as the chlorophyll concentration. A semi-analytical bio-optical algorithm is used to help interpret regional to global SeaWiFS chlorophyll observations from using three independent, well-validated ocean color data products; the chlorophyll a concentration, absorption by CDM and particulate backscattering. First, we show that observed long-term, global-scale trends in standard chlorophyll retrievals are likely compromised by coincident changes in CDM. Second, we partition the chlorophyll signal into a component due to phytoplankton biomass changes and a component caused by physiological adjustments in intracellular chlorophyll concentrations to changes in mixed layer light levels. We show that biomass changes dominate chlorophyll signals for the high latitude seas and where persistent vertical upwelling is known to occur, while physiological processes dominate chlorophyll variability over much of the tropical and subtropical oceans. The SeaWiFS data set demonstrates complexity in the interpretation of changes in regional to global phytoplankton distributions and illustrates limitations for the assessment of phytoplankton dynamics using chlorophyll

  2. Received Signal Strength Database Interpolation by Kriging for a Wi-Fi Indoor Positioning System.

    Science.gov (United States)

    Jan, Shau-Shiun; Yeh, Shuo-Ju; Liu, Ya-Wen

    2015-08-28

    The main approach for a Wi-Fi indoor positioning system is based on the received signal strength (RSS) measurements, and the fingerprinting method is utilized to determine the user position by matching the RSS values with the pre-surveyed RSS database. To build a RSS fingerprint database is essential for an RSS based indoor positioning system, and building such a RSS fingerprint database requires lots of time and effort. As the range of the indoor environment becomes larger, labor is increased. To provide better indoor positioning services and to reduce the labor required for the establishment of the positioning system at the same time, an indoor positioning system with an appropriate spatial interpolation method is needed. In addition, the advantage of the RSS approach is that the signal strength decays as the transmission distance increases, and this signal propagation characteristic is applied to an interpolated database with the Kriging algorithm in this paper. Using the distribution of reference points (RPs) at measured points, the signal propagation model of the Wi-Fi access point (AP) in the building can be built and expressed as a function. The function, as the spatial structure of the environment, can create the RSS database quickly in different indoor environments. Thus, in this paper, a Wi-Fi indoor positioning system based on the Kriging fingerprinting method is developed. As shown in the experiment results, with a 72.2% probability, the error of the extended RSS database with Kriging is less than 3 dBm compared to the surveyed RSS database. Importantly, the positioning error of the developed Wi-Fi indoor positioning system with Kriging is reduced by 17.9% in average than that without Kriging.

  3. Monitoring and remote control of energy consumption by WiFi networks. Smart energy saving platform

    OpenAIRE

    Zarza Sánchez, Sergio; Fernández Canti, Rosa M.; Lázaro Villa, José Antonio; Ortega Gómez, Isidre; Altabas, Jose Antonio

    2014-01-01

    In this paper we present a modular system for remote monitoring and control of energy consumption. In particular, we demonstrate the application of the proposed system for electric energy monitoring and control in domestic or medium size office installations. This whole system is integrated in a single platform and consists of different modules: one or several smart plugs including a wireless communication interface for connection to a WiFi network, and a centralized application server. The d...

  4. Návrh rozšíření WiFi sítě

    OpenAIRE

    Zahradník, Tomáš

    2008-01-01

    Tato bakalářská práce se zabývá rozsáhlou WiFi sítí společnosti VIVO CONNECTION s.r.o. a návrhem jejího rozšíření. The Bachelor work deals with the project of WiFi network expansion for VIVO CONNECTION s.r.o. company. B

  5. WiMAX OFDM system simulation and sub-system FPGA implementation

    International Nuclear Information System (INIS)

    Elaskary, A.M.F.

    2009-01-01

    Orthogonal frequency division multiplexing (OFDM) has been used in many wireless communication systems also it is gaining a lot of attention for the next generations of mobile communication systems. OFDM is considered a good candidate for wireless systems because it has high bandwidth efficiency and can transmit at very high data rate in multi path, interference , and fading environment. in general OFDM has widely been studied and implemented to combat transmission channel impairments, but some challenges still facing OFDM in transmission system implementation especially for recent and future applications. One of these important applications is the worldwide interoperability for microwave access (WiMAX) system. According to the IEEE 802.16 standards, WiMAX is considered as a good solution for last mile connection at crowded areas and a high-speed internet connection to mobile vehicles with speed of up to 300 km/h. This thesis studies OFDM system in details and proposes simulink models for simulating OFDM impairments and its effects on system performance. This study has been used for building up system level and end to end WiMAX OFDM transmitter/receiver which follows published specifications in IEEE 802.16 standards using mat lab/simulink.

  6. Fair Adaptive Bandwidth and Subchannel Allocation in the WiMAX Uplink

    Directory of Open Access Journals (Sweden)

    Antoni Morell

    2009-01-01

    Full Text Available In some modern communication systems, as it is the case of WiMAX, it has been decided to implement Demand Assignment Multiple Access (DAMA solutions. End-users request transmission opportunities before accessing the system, which provides an efficient way to share system resources. In this paper, we briefly review the PHY and MAC layers of an OFDMA-based WiMAX system, and we propose to use a Network Utility Maximization (NUM framework to formulate the DAMA strategy foreseen in the uplink of IEEE 802.16. Utility functions are chosen to achieve fair solutions attaining different degrees of fairness and to further support the QoS requirements of the services in the system. Moreover, since the standard allocates resources in a terminal basis but each terminal may support several services, we develop a new decomposition technique, the coupled-decompositions method, that obtains the optimal service flow allocation with a small number of iterations (the improvement is significant when compared to other known solutions. Furthermore, since the PHY layer in mobile WiMAX has the means to adapt the transport capacities of the links between the Base Station (BS and the Subscriber Stations (SSs, the proposed PHY-MAC cross-layer design uses this extra degree of freedom in order to enhance the network utility.

  7. The Making of a Sustainable Wireless City? Mapping Public Wi-Fi Access in Shanghai

    Directory of Open Access Journals (Sweden)

    Mingfeng Wang

    2016-01-01

    Full Text Available In the context of the global information economy, ready access to the Internet is critical to a city’s competitiveness, which has prompted a number of cities to launch plans to establish wireless networks. Most literature on the development of wireless cities focuses on cities in Western countries, and few have discussed how Chinese cities have adopted wireless technologies in their urban infrastructure development efforts. This paper examines recent development and spatial distribution of public Wi-Fi access in Shanghai, a leading business hub in China. We mapped Wi-Fi hotspots through the government sponsored “i-Shanghai” project and China Mobile Communications Corporation (CMCC. We find that while telecommunication providers have been proactively deploying WLAN (wireless local area network,a proxy of public Wi-Fi or wireless access hotspots in Shanghai, neither government sponsored WLAN hotspots nor facilities established by CMCC could cover the old traditional neighborhoods in the central city and sub-districts in remote rural areas. We also address the development of a more sustainable wireless city in Shanghai with a particular focus on digital divide and social equity issues.

  8. Design of smart home gateway based on Wi-Fi and ZigBee

    Science.gov (United States)

    Li, Yang

    2018-04-01

    With the increasing demand for home lifestyle, the traditional smart home products have been unable to meet the needs of users. Aim at the complex wiring, high cost and difficult operation problems of traditional smart home system, this paper designs a home gateway for smart home system based on Wi-Fi and ZigBee. This paper first gives a smart home system architecture base on cloud server, Wi-Fi and ZigBee. This architecture enables users to access the smart home system remotely from Internet through the cloud server or through Wi-Fi at home. It also offers the flexibility and low cost of ZigBee wireless networking for home equipment. This paper analyzes the functional requirements of the home gateway, and designs a modular hardware architecture based on the RT5350 wireless gateway module and the CC2530 ZigBee coordinator module. Also designs the software of the home gateway, including the gateway master program and the ZigBee coordinator program. Finally, the smart home system and home gateway are tested in two kinds of network environments, internal network and external network. The test results show that the designed home gateway can meet the requirements, support remote and local access, support multi-user, support information security technology, and can timely report equipment status information.

  9. Fusion of WiFi, Smartphone Sensors and Landmarks Using the Kalman Filter for Indoor Localization

    Directory of Open Access Journals (Sweden)

    Zhenghua Chen

    2015-01-01

    Full Text Available Location-based services (LBS have attracted a great deal of attention recently. Outdoor localization can be solved by the GPS technique, but how to accurately and efficiently localize pedestrians in indoor environments is still a challenging problem. Recent techniques based on WiFi or pedestrian dead reckoning (PDR have several limiting problems, such as the variation of WiFi signals and the drift of PDR. An auxiliary tool for indoor localization is landmarks, which can be easily identified based on specific sensor patterns in the environment, and this will be exploited in our proposed approach. In this work, we propose a sensor fusion framework for combining WiFi, PDR and landmarks. Since the whole system is running on a smartphone, which is resource limited, we formulate the sensor fusion problem in a linear perspective, then a Kalman filter is applied instead of a particle filter, which is widely used in the literature. Furthermore, novel techniques to enhance the accuracy of individual approaches are adopted. In the experiments, an Android app is developed for real-time indoor localization and navigation. A comparison has been made between our proposed approach and individual approaches. The results show significant improvement using our proposed framework. Our proposed system can provide an average localization accuracy of 1 m.

  10. PDR/INS/WiFi Integration Based on Handheld Devices for Indoor Pedestrian Navigation

    Directory of Open Access Journals (Sweden)

    Yuan Zhuang

    2015-06-01

    Full Text Available Providing an accurate and practical navigation solution anywhere with portable devices, such as smartphones, is still a challenge, especially in environments where global navigation satellite systems (GNSS signals are not available or are degraded. This paper proposes a new algorithm that integrates inertial navigation system (INS and pedestrian dead reckoning (PDR to combine the advantages of both mechanizations for micro-electro-mechanical systems (MEMS sensors in pedestrian navigation applications. In this PDR/INS integration algorithm, a pseudo-velocity-vector, which is composed of the PDR-derived forward speed and zero lateral and vertical speeds from non-holonomic constraints (NHC, works as an update for the INS to limit the velocity errors. To further limit the drift of MEMS inertial sensors, trilateration-based WiFi positions with small variances are also selected as updates for the PDR/INS integrated system. The experiments illustrate that positioning error is decreased by 60%–75% by using the proposed PDR/INS integrated MEMS solution when compared with PDR. The positioning error is further decreased by 15%–55% if the proposed PDR/INS/WiFi integrated solution is implemented. The average accuracy of the proposed PDR/INS/WiFi integration algorithm achieves 4.5 m in indoor environments.

  11. Cooperation Techniques between LTE in Unlicensed Spectrum and Wi-Fi towards Fair Spectral Efficiency.

    Science.gov (United States)

    Maglogiannis, Vasilis; Naudts, Dries; Shahid, Adnan; Giannoulis, Spilios; Laermans, Eric; Moerman, Ingrid

    2017-08-31

    On the road towards 5G, a proliferation of Heterogeneous Networks (HetNets) is expected. Sensor networks are of great importance in this new wireless era, as they allow interaction with the environment. Additionally, the establishment of the Internet of Things (IoT) has incredibly increased the number of interconnected devices and consequently the already massive wirelessly transmitted traffic. The exponential growth of wireless traffic is pushing the wireless community to investigate solutions that maximally exploit the available spectrum. Recently, 3rd Generation Partnership Project (3GPP) announced standards that permit the operation of Long Term Evolution (LTE) in the unlicensed spectrum in addition to the exclusive use of the licensed spectrum owned by a mobile operator. Alternatively, leading wireless technology developers examine standalone LTE operation in the unlicensed spectrum without any involvement of a mobile operator. In this article, we present a classification of different techniques that can be applied on co-located LTE and Wi-Fi networks. Up to today, Wi-Fi is the most widely-used wireless technology in the unlicensed spectrum. A review of the current state of the art further reveals the lack of cooperation schemes among co-located networks that can lead to more optimal usage of the available spectrum. This article fills this gap in the literature by conceptually describing different classes of cooperation between LTE and Wi-Fi. For each class, we provide a detailed presentation of possible cooperation techniques that can provide spectral efficiency in a fair manner.

  12. WiFiabe: un’esperienza di storytelling dal territorio al web 2.0

    Directory of Open Access Journals (Sweden)

    Marco Carnesecchi

    2013-03-01

    Full Text Available L’impatto iniziale di WiRoni sulla popolazione di Monteroni d’Arbia (Siena è stato limitato alla fruizione dei contenuti caricati dal team di design, in particolare le storie per i bambini. Mancavano infatti brani audio prodotti dalla comunità locale. In realtà, però, la competenza tecnica necessaria a trasmettere i contenuti nel parco e in rete è minima (upload da CMS wordpress e anche le tecnologie per registrare e arricchire l’audio con effetti sonori sono alla portata di tutti, se opportunamente guidati da esperti. Da queste osservazioni è nato il progetto WiFiabe. Nel corso dell’anno scolastico 2010/2011 20 bambini tra 6 e 13 anni, coordinati da un’educatrice durante l’attività di doposcuola del Comune, hanno lavorato in gruppi e creato storie di fantasia. In seguito, alcuni studenti dell’Università di Siena, con l’aiuto di un musicista per la parte degli effetti sonori, hanno assistito i ragazzi nel diventare autori digitali e apprendere in prima persona come trasformare le loro storie in contenuti audio. In questo modo i partecipanti hanno interagito con il web non in quanto fruitori ma come autori, e messo in moto un processo per rendere WiRoni uno strumento per dare voce alle varie anime della comunità.

  13. A Map/INS/Wi-Fi Integrated System for Indoor Location-Based Service Applications.

    Science.gov (United States)

    Yu, Chunyang; Lan, Haiyu; Gu, Fuqiang; Yu, Fei; El-Sheimy, Naser

    2017-06-02

    In this research, a new Map/INS/Wi-Fi integrated system for indoor location-based service (LBS) applications based on a cascaded Particle/Kalman filter framework structure is proposed. Two-dimension indoor map information, together with measurements from an inertial measurement unit (IMU) and Received Signal Strength Indicator (RSSI) value, are integrated for estimating positioning information. The main challenge of this research is how to make effective use of various measurements that complement each other in order to obtain an accurate, continuous, and low-cost position solution without increasing the computational burden of the system. Therefore, to eliminate the cumulative drift caused by low-cost IMU sensor errors, the ubiquitous Wi-Fi signal and non-holonomic constraints are rationally used to correct the IMU-derived navigation solution through the extended Kalman Filter (EKF). Moreover, the map-aiding method and map-matching method are innovatively combined to constrain the primary Wi-Fi/IMU-derived position through an Auxiliary Value Particle Filter (AVPF). Different sources of information are incorporated through a cascaded structure EKF/AVPF filter algorithm. Indoor tests show that the proposed method can effectively reduce the accumulation of positioning errors of a stand-alone Inertial Navigation System (INS), and provide a stable, continuous and reliable indoor location service.

  14. Rat fertility and embryo fetal development: influence of exposure to the Wi-Fi signal.

    Science.gov (United States)

    Poulletier de Gannes, Florence; Billaudel, Bernard; Haro, Emmanuelle; Taxile, Murielle; Le Montagner, Laureline; Hurtier, Annabelle; Ait Aissa, Saliha; Masuda, Hiroshi; Percherancier, Yann; Ruffié, Gilles; Dufour, Philippe; Veyret, Bernard; Lagroye, Isabelle

    2013-04-01

    In recent decades, concern has been growing about decreasing fecundity and fertility in the human population. Exposure to non-ionizing electromagnetic fields (EMF), especially radiofrequency (RF) fields used in wireless communications has been suggested as a potential risk factor. For the first time, we evaluated the effects of exposure to the 2450MHz Wi-Fi signal (1h/day, 6days/week) on the reproductive system of male and female Wistar rats, pre-exposed to Wi-Fi during sexual maturation. Exposure lasted 3 weeks (males) or 2 weeks (females), then animals were mated and couples exposed for 3 more weeks. On the day before delivery, the fetuses were observed for lethality, abnormalities, and clinical signs. In our experiment, no deleterious effects of Wi-Fi exposure on rat male and female reproductive organs and fertility were observed for 1h per days. No macroscopic abnormalities in fetuses were noted, even at the critical level of 4W/kg. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Indoor Location Sensing with Invariant Wi-Fi Received Signal Strength Fingerprinting.

    Science.gov (United States)

    Husen, Mohd Nizam; Lee, Sukhan

    2016-11-11

    A method of location fingerprinting based on the Wi-Fi received signal strength (RSS) in an indoor environment is presented. The method aims to overcome the RSS instability due to varying channel disturbances in time by introducing the concept of invariant RSS statistics. The invariant RSS statistics represent here the RSS distributions collected at individual calibration locations under minimal random spatiotemporal disturbances in time. The invariant RSS statistics thus collected serve as the reference pattern classes for fingerprinting. Fingerprinting is carried out at an unknown location by identifying the reference pattern class that maximally supports the spontaneous RSS sensed from individual Wi-Fi sources. A design guideline is also presented as a rule of thumb for estimating the number of Wi-Fi signal sources required to be available for any given number of calibration locations under a certain level of random spatiotemporal disturbances. Experimental results show that the proposed method not only provides 17% higher success rate than conventional ones but also removes the need for recalibration. Furthermore, the resolution is shown finer by 40% with the execution time more than an order of magnitude faster than the conventional methods. These results are also backed up by theoretical analysis.

  16. An Android/LAMP Mobile In/Out Board Based on Wi-Fi Fingerprinting

    Directory of Open Access Journals (Sweden)

    Keith Kelley

    2011-10-01

    Full Text Available Library technology and other professionals with diverse skills must be able to locate each other during the workday, in order to most responsively serve their clients. While staff often carry cellular phones, contact can be especially challenging given the constant, highly mobile nature of library work, especially on larger campuses with variable cellular phone service. Western Michigan University (WMU Libraries has developed an Android/LAMP application that library staff may use on their increasingly prevalent Wi-Fi enabled mobile devices to “check in” at various locations where they do work, so that their colleagues may locate them as needed. The application takes advantage of WMU’s widespread Wi-Fi network, a set of free platform and software development tools and open standards, and methods from the computer science literature, and overcomes GPS and telephony limitations. This article describes the application, which is based on Wi-Fi fingerprinting, and suggests how other developers could use it and new methods from the computer science literature as starting points to create their own applications.

  17. INDOOR LOCALIZATION USING WI-FI BASED FINGERPRINTING AND TRILATERATION TECHIQUES FOR LBS APPLICATIONS

    Directory of Open Access Journals (Sweden)

    S. Chan

    2012-06-01

    Full Text Available The past few years have seen wide spread adoption of outdoor positioning services, mainly GPS, being incorporated into everyday devices such as smartphones and tablets. While outdoor positioning has been well received by the public, its indoor counterpart has been mostly limited to private use due to its higher costs and complexity for setting up the proper environment. The objective of this research is to provide an affordable mean for indoor localization using wireless local area network (WLAN Wi-Fi technology. We combined two different Wi-Fi approaches to locate a user. The first method involves the use of matching the pre-recorded received signal strength (RSS from nearby access points (AP, to the data transmitted from the user on the fly. This is commonly known as "fingerprint matching". The second approach is a distance-based trilateration approach using three known AP coordinates detected on the user's device to derive the position. The combination of the two steps enhances the accuracy of the user position in an indoor environment allowing location-based services (LBS such as mobile augmented reality (MAR to be deployed more effectively in the indoor environment. The mapping of the RSS map can also prove useful to IT planning personnel for covering locations with no Wi-Fi coverage (ie. dead spots. The experiments presented in this research helps provide a foundation for the integration of indoor with outdoor positioning to create a seamless transition experience for users.

  18. Investigation of a new handover approach in LTE and WiMAX.

    Science.gov (United States)

    Hindia, Mohammad Nour; Reza, Ahmed Wasif; Noordin, Kamarul Ariffin

    2014-01-01

    Nowadays, one of the most important challenges in heterogeneous networks is the connection consistency between the mobile station and the base stations. Furthermore, along the roaming process between the mobile station and the base station, the system performance degrades significantly due to the interferences from neighboring base stations, handovers to inaccurate base station and inappropriate technology selection. In this paper, several algorithms are proposed to improve mobile station performance and seamless mobility across the long-term evolution (LTE) and Worldwide Interoperability for Microwave Access (WiMAX) technologies, along with a minimum number of redundant handovers. Firstly, the enhanced global positioning system (GPS) and the novel received signal strength (RSS) prediction approaches are suggested to predict the target base station accurately. Then, the multiple criteria with two thresholds algorithm is proposed to prioritize the selection between LTE and WiMAX as the target technology. In addition, this study also covers the intercell and cochannel interference reduction by adjusting the frequency reuse ratio 3 (FRR3) to work with LTE and WiMAX. The obtained results demonstrate high next base station prediction efficiency and high accuracy for both horizontal and vertical handovers. Moreover, the received signal strength is kept at levels higher than the threshold, while maintaining low connection cost and delay within acceptable levels. In order to highlight the combination of the proposed algorithms' performance, it is compared with the existing RSS and multiple criteria handover decision algorithms.

  19. Indoor Location Sensing with Invariant Wi-Fi Received Signal Strength Fingerprinting

    Directory of Open Access Journals (Sweden)

    Mohd Nizam Husen

    2016-11-01

    Full Text Available A method of location fingerprinting based on the Wi-Fi received signal strength (RSS in an indoor environment is presented. The method aims to overcome the RSS instability due to varying channel disturbances in time by introducing the concept of invariant RSS statistics. The invariant RSS statistics represent here the RSS distributions collected at individual calibration locations under minimal random spatiotemporal disturbances in time. The invariant RSS statistics thus collected serve as the reference pattern classes for fingerprinting. Fingerprinting is carried out at an unknown location by identifying the reference pattern class that maximally supports the spontaneous RSS sensed from individual Wi-Fi sources. A design guideline is also presented as a rule of thumb for estimating the number of Wi-Fi signal sources required to be available for any given number of calibration locations under a certain level of random spatiotemporal disturbances. Experimental results show that the proposed method not only provides 17% higher success rate than conventional ones but also removes the need for recalibration. Furthermore, the resolution is shown finer by 40% with the execution time more than an order of magnitude faster than the conventional methods. These results are also backed up by theoretical analysis.

  20. Fusion of WiFi, smartphone sensors and landmarks using the Kalman filter for indoor localization.

    Science.gov (United States)

    Chen, Zhenghua; Zou, Han; Jiang, Hao; Zhu, Qingchang; Soh, Yeng Chai; Xie, Lihua

    2015-01-05

    Location-based services (LBS) have attracted a great deal of attention recently. Outdoor localization can be solved by the GPS technique, but how to accurately and efficiently localize pedestrians in indoor environments is still a challenging problem. Recent techniques based on WiFi or pedestrian dead reckoning (PDR) have several limiting problems, such as the variation of WiFi signals and the drift of PDR. An auxiliary tool for indoor localization is landmarks, which can be easily identified based on specific sensor patterns in the environment, and this will be exploited in our proposed approach. In this work, we propose a sensor fusion framework for combining WiFi, PDR and landmarks. Since the whole system is running on a smartphone, which is resource limited, we formulate the sensor fusion problem in a linear perspective, then a Kalman filter is applied instead of a particle filter, which is widely used in the literature. Furthermore, novel techniques to enhance the accuracy of individual approaches are adopted. In the experiments, an Android app is developed for real-time indoor localization and navigation. A comparison has been made between our proposed approach and individual approaches. The results show significant improvement using our proposed framework. Our proposed system can provide an average localization accuracy of 1 m.

  1. Developing an active emergency medical service system based on WiMAX technology.

    Science.gov (United States)

    Li, Shing-Han; Cheng, Kai-An; Lu, Wen-Hui; Lin, Te-Chang

    2012-10-01

    The population structure has changed with the aging of population. In the present, elders account for 10.63% of the domestic population and the percentage is still gradually climbing. In other words, the demand for emergency services among elders in home environment is expected to grow in the future. In order to improve the efficiency and quality of emergency care, information technology should be effectively utilized to integrate medical systems and facilities, strengthen human-centered operation designs, and maximize the overall performance. The improvement in the quality and survival rate of emergency care is an important basis for better life and health of all people. Through integrated application of medical information systems and information communication technology, this study proposes a WiMAX-based emergency care system addressing the public demands for convenience, speed, safety, and human-centered operation of emergency care. This system consists of a healthcare service center, emergency medical service hospitals, and emergency ambulances. Using the wireless transmission capability of WiMAX, patients' physiological data can be transmitted from medical measurement facilities to the emergency room and emergency room doctors can provide immediate online instructions on emergency treatment via video and audio transmission. WiMAX technology enables the establishment of active emergency medical services.

  2. Wake-on-a-Schedule: Energy-aware Communication in Wi-Fi Networks

    Directory of Open Access Journals (Sweden)

    PERKOVIC, T.

    2014-02-01

    Full Text Available Excessive energy consumption of mobile device Wi-Fi (IEEE 802.11x interface is limiting its operational time on batteries, and impacts total energy consumption of electronic devices. In recent years research community has invested great effort in better efficiency of energy consumption. However, there is still a space for improvement. Wi-Fi devices connected to the single AP (Access Point compete for the medium during data exchange. However, due to the performance anomaly in 802.11 networks, a low data rate device will force all other devices connected to the AP to communicate at low rate, which will increase the total energy consumption of these devices. Wake-on-a-Schedule algorithm is proposed reducing the energy consumption of devices placed in the area with the weaker signal by scheduling the data packets for each client on the server side which will not allow clients to compete for the Wi-Fi medium. Through extensive measurements we show that our algorithm can save up to 60% of energy consumption on the client side.

  3. Rectangular Ring Antenna Excited by Circular Disc Monopole for WiMAX System

    Directory of Open Access Journals (Sweden)

    Souphanna Vongsack

    2014-01-01

    Full Text Available This research presents a rectangular ring antenna excited by a circular disc monopole (CDM mounted in front of a square reflector. The proposed antenna is designed to cover a frequency range of 2.300–5.825 GHz and thereby is suitable for WiMAX applications. Multiple parametric studies were carried out using the CST Microwave Studio simulation program. A prototype antenna was fabricated and experimented. The measurements were taken and compared with the simulation results, which indicates good agreement between both results. The prototype antenna produces an impedance bandwidth (|S11| < −10 dB that covers the WiMAX frequency range and a constant unidirectional radiation pattern (θ=0° and ∅=90°. The minimum and maximum gains are 3.7 and 8.7 dBi, respectively. The proposed antenna is of compact size and has good unidirectional radiation performance. Thus, it is very suitable for a multitude of WiMAX applications.

  4. Zingiber officinale, Piper retrofractum and Combination Induced Apoptosis and p53 Expression in Myeloma and WiDr Cell Lines

    Directory of Open Access Journals (Sweden)

    HENY EKOWATI

    2012-09-01

    Full Text Available In previous studies, Zingiber officinale, Piper retrofractum, and the combination showed cytotoxic activity, induced apoptosis, and p53 expression of HeLa, T47D, and MCF-7 cell lines. This study was conducted to investigate the cytotoxic and apoptotic activity of Zingiber officinale (ZO, Piper retrofractum (PR, and the combination as well as their effect to p53 expression on Myeloma and WiDr cells. The powder of ZO, PR, and ZO + PR combination (1:1 were macerated with 96% ethanol for 3 x 24 hours. MTT cytotoxic assay was performed on Myeloma and WiDr cell lines. Apoptotic cells were stained with ethidium bromide and acridine orange. Imunohistochemical expression of p53 was examined on Myeloma and WiDr cell lines. Doxorubicin was used as positive control in all assays. Results showed that ZO, PR, and ZO + PR combination had cytotoxic activity on Myeloma cells with IC50 of 28, 36, and 55 mg/ml respectively and WiDr cell lines with IC50 of 74, 158, and 64 mg/ml respectively, induced apoptotic activity, and increased p53 expression on Myeloma and WiDr cells. These results suggest that ZO, PR, and their combination induced Myeloma and WiDr cells in apoptosis through p53 expression.

  5. Circulation of Stars

    Science.gov (United States)

    Boitani, P.

    2016-01-01

    Since the dawn of man, contemplation of the stars has been a primary impulse in human beings, who proliferated their knowledge of the stars all over the world. Aristotle sees this as the product of primeval and perennial “wonder” which gives rise to what we call science, philosophy, and poetry. Astronomy, astrology, and star art (painting, architecture, literature, and music) go hand in hand through millennia in all cultures of the planet (and all use catasterisms to explain certain phenomena). Some of these developments are independent of each other, i.e., they take place in one culture independently of others. Some, on the other hand, are the product of the “circulation of stars.” There are two ways of looking at this. One seeks out forms, the other concentrates on the passing of specific lore from one area to another through time. The former relies on archetypes (for instance, with catasterism), the latter constitutes a historical process. In this paper I present some of the surprising ways in which the circulation of stars has occurred—from East to West, from East to the Far East, and from West to East, at times simultaneously.

  6. Stars a very short introduction

    CERN Document Server

    King, Andrew

    2012-01-01

    Stars: A Very Short Introduction looks at how stars live, producing all the chemical elements beyond helium, and how they die, leaving remnants such as black holes. Every atom of our bodies has been part of a star. Our very own star, the Sun, is crucial to the development and sustainability of life on Earth. Understanding stars is key to understanding the galaxies they inhabit, the existence of planets, and the history of our entire Universe. This VSI explores the science of stars, the mechanisms that allow them to form, the processes that allow them to shine, and the results of their death.

  7. Lithium in LMC carbon stars

    OpenAIRE

    Hatzidimitriou, D.; Morgan, D. H.; Cannon, R. D.; Croke, B. F. W.

    2003-01-01

    Nineteen carbon stars that show lithium enrichment in their atmospheres have been discovered among a sample of 674 carbon stars in the Large Magellanic Cloud. Six of the Li-rich carbon stars are of J-type, i.e. with strong 13C isotopic features. No super-Li-rich carbon stars were found. The incidence of lithium enrichment among carbon stars in the LMC is much rarer than in the Galaxy, and about five times more frequent among J-type than among N-type carbon stars. The bolometric magnitudes of ...

  8. [North] Korea.

    Science.gov (United States)

    1986-05-01

    In 1985, the population of the Democratic People's Republic of Korea (North Korea) stood at 20 million, with an annual growth rate of 2.3%. The infant mortality rate was 30/1000 live births and life expectancy was 66 years. The gross national product (GNP) was US$23 billion in 1984, with a per capita GNP of $1175. Both North Korea's labor force and natural resources have been concentrated in recent years on an effort to achieve rapid economic development. During the early 1970s, a large-scale modernization program involving the importation of Western technology, primarily in the heavy industiral sectors of the economy, was attempted and resulted in a massive foreign debt. North Korea has a strongly centralized government under the control of the communist Korean Workers' Party. Literacy in the country is at the 99% level. Medical treatment is free. There is 1 physician/600 population and 1 hospital bed/350 inhabitants.

  9. Dynamical Boson Stars

    Directory of Open Access Journals (Sweden)

    Steven L. Liebling

    2012-05-01

    Full Text Available The idea of stable, localized bundles of energy has strong appeal as a model for particles. In the 1950s, John Wheeler envisioned such bundles as smooth configurations of electromagnetic energy that he called geons, but none were found. Instead, particle-like solutions were found in the late 1960s with the addition of a scalar field, and these were given the name boson stars. Since then, boson stars find use in a wide variety of models as sources of dark matter, as black hole mimickers, in simple models of binary systems, and as a tool in finding black holes in higher dimensions with only a single Killing vector. We discuss important varieties of boson stars, their dynamic properties, and some of their uses, concentrating on recent efforts.

  10. Instability and star evolution

    International Nuclear Information System (INIS)

    Mirzoyan, L.V.

    1981-01-01

    The observational data are discussed which testify that the phenomena of dynamical instability of stars and stellar systems are definite manifestations of their evolution. The study of these phenomena has shown that the instability is a regular phase of stellar evolution. It has resulted in the recognition of the most important regularities of the process of star formation concerning its nature. This became possible due to the discovery in 1947 of stellar associations in our Galaxy. The results of the study of the dynamical instability of stellar associations contradict the predictions of classical hypothesis of stellar condensation. These data supplied a basis for a new hypothesis on the formation of stars and nebulae by the decay of superdense protostars [ru

  11. Atomic diffusion in stars

    CERN Document Server

    Michaud, Georges; Richer, Jacques

    2015-01-01

    This book gives an overview of atomic diffusion, a fundamental physical process, as applied to all types of stars, from the main sequence to neutron stars. The superficial abundances of stars as well as their evolution can be significantly affected. The authors show where atomic diffusion plays an essential role and how it can be implemented in modelling.  In Part I, the authors describe the tools that are required to include atomic diffusion in models of stellar interiors and atmospheres. An important role is played by the gradient of partial radiative pressure, or radiative acceleration, which is usually neglected in stellar evolution. In Part II, the authors systematically review the contribution of atomic diffusion to each evolutionary step. The dominant effects of atomic diffusion are accompanied by more subtle effects on a large number of structural properties throughout evolution. One of the goals of this book is to provide the means for the astrophysicist or graduate student to evaluate the importanc...

  12. The twinkling of stars

    International Nuclear Information System (INIS)

    Jakeman, E.; Parry, G.; Pike, E.R.; Pusey, P.N.

    1978-01-01

    This article collects together some of the main ideas and experimental results on the twinkling of stars. Statistical methods are used to characterise the features of the scintillation and to investigate the ways in which these depend on the zenith angle of the star, the bandwidth of the light and various other parameters. Some new results are included which demonstrate the advantages of using photon counting methods in experiments on stellar scintillation. Since the twinkling of stars is a consequence of the turbulence in the Earth's magnetic atmosphere then measurements can be used to deduce some features of the structure of the turbulence. Some of the experiments designed to do this are discussed and the results reported. (author)

  13. Pulsating Star Mystery Solved

    Science.gov (United States)

    2010-11-01

    By discovering the first double star where a pulsating Cepheid variable and another star pass in front of one another, an international team of astronomers has solved a decades-old mystery. The rare alignment of the orbits of the two stars in the double star system has allowed a measurement of the Cepheid mass with unprecedented accuracy. Up to now astronomers had two incompatible theoretical predictions of Cepheid masses. The new result shows that the prediction from stellar pulsation theory is spot on, while the prediction from stellar evolution theory is at odds with the new observations. The new results, from a team led by Grzegorz Pietrzyński (Universidad de Concepción, Chile, Obserwatorium Astronomiczne Uniwersytetu Warszawskiego, Poland), appear in the 25 November 2010 edition of the journal Nature. Grzegorz Pietrzyński introduces this remarkable result: "By using the HARPS instrument on the 3.6-metre telescope at ESO's La Silla Observatory in Chile, along with other telescopes, we have measured the mass of a Cepheid with an accuracy far greater than any earlier estimates. This new result allows us to immediately see which of the two competing theories predicting the masses of Cepheids is correct." Classical Cepheid Variables, usually called just Cepheids, are unstable stars that are larger and much brighter than the Sun [1]. They expand and contract in a regular way, taking anything from a few days to months to complete the cycle. The time taken to brighten and grow fainter again is longer for stars that are more luminous and shorter for the dimmer ones. This remarkably precise relationship makes the study of Cepheids one of the most effective ways to measure the distances to nearby galaxies and from there to map out the scale of the whole Universe [2]. Unfortunately, despite their importance, Cepheids are not fully understood. Predictions of their masses derived from the theory of pulsating stars are 20-30% less than predictions from the theory of the

  14. General Relativity&Compact Stars

    Energy Technology Data Exchange (ETDEWEB)

    Glendenning, Norman K.

    2005-08-16

    Compact stars--broadly grouped as neutron stars and white dwarfs--are the ashes of luminous stars. One or the other is the fate that awaits the cores of most stars after a lifetime of tens to thousands of millions of years. Whichever of these objects is formed at the end of the life of a particular luminous star, the compact object will live in many respects unchanged from the state in which it was formed. Neutron stars themselves can take several forms--hyperon, hybrid, or strange quark star. Likewise white dwarfs take different forms though only in the dominant nuclear species. A black hole is probably the fate of the most massive stars, an inaccessible region of spacetime into which the entire star, ashes and all, falls at the end of the luminous phase. Neutron stars are the smallest, densest stars known. Like all stars, neutron stars rotate--some as many as a few hundred times a second. A star rotating at such a rate will experience an enormous centrifugal force that must be balanced by gravity or else it will be ripped apart. The balance of the two forces informs us of the lower limit on the stellar density. Neutron stars are 10{sup 14} times denser than Earth. Some neutron stars are in binary orbit with a companion. Application of orbital mechanics allows an assessment of masses in some cases. The mass of a neutron star is typically 1.5 solar masses. They can therefore infer their radii: about ten kilometers. Into such a small object, the entire mass of our sun and more, is compressed.

  15. General Relativity and Compact Stars

    International Nuclear Information System (INIS)

    Glendenning, Norman K.

    2005-01-01

    Compact stars--broadly grouped as neutron stars and white dwarfs--are the ashes of luminous stars. One or the other is the fate that awaits the cores of most stars after a lifetime of tens to thousands of millions of years. Whichever of these objects is formed at the end of the life of a particular luminous star, the compact object will live in many respects unchanged from the state in which it was formed. Neutron stars themselves can take several forms--hyperon, hybrid, or strange quark star. Likewise white dwarfs take different forms though only in the dominant nuclear species. A black hole is probably the fate of the most massive stars, an inaccessible region of spacetime into which the entire star, ashes and all, falls at the end of the luminous phase. Neutron stars are the smallest, densest stars known. Like all stars, neutron stars rotate--some as many as a few hundred times a second. A star rotating at such a rate will experience an enormous centrifugal force that must be balanced by gravity or else it will be ripped apart. The balance of the two forces informs us of the lower limit on the stellar density. Neutron stars are 10 14 times denser than Earth. Some neutron stars are in binary orbit with a companion. Application of orbital mechanics allows an assessment of masses in some cases. The mass of a neutron star is typically 1.5 solar masses. They can therefore infer their radii: about ten kilometers. Into such a small object, the entire mass of our sun and more, is compressed

  16. Chaplygin dark star

    International Nuclear Information System (INIS)

    Bertolami, O.; Paramos, J.

    2005-01-01

    We study the general properties of a spherically symmetric body described through the generalized Chaplygin equation of state. We conclude that such an object, dubbed generalized Chaplygin dark star, should exist within the context of the generalized Chaplygin gas (GCG) model of unification of dark energy and dark matter, and derive expressions for its size and expansion velocity. A criteria for the survival of the perturbations in the GCG background that give origin to the dark star are developed, and its main features are analyzed

  17. The formation of stars

    CERN Document Server

    Stahler, Steven W

    2008-01-01

    This book is a comprehensive treatment of star formation, one of the most active fields of modern astronomy. The reader is guided through the subject in a logically compelling manner. Starting from a general description of stars and interstellar clouds, the authors delineate the earliest phases of stellar evolution. They discuss formation activity not only in the Milky Way, but also in other galaxies, both now and in the remote past. Theory and observation are thoroughly integrated, with the aid of numerous figures and images. In summary, this volume is an invaluable resource, both as a text f

  18. Synthetic guide star generation

    Science.gov (United States)

    Payne, Stephen A [Castro Valley, CA; Page, Ralph H [Castro Valley, CA; Ebbers, Christopher A [Livermore, CA; Beach, Raymond J [Livermore, CA

    2008-06-10

    A system for assisting in observing a celestial object and providing synthetic guide star generation. A lasing system provides radiation at a frequency at or near 938 nm and radiation at a frequency at or near 1583 nm. The lasing system includes a fiber laser operating between 880 nm and 960 nm and a fiber laser operating between 1524 nm and 1650 nm. A frequency-conversion system mixes the radiation and generates light at a frequency at or near 589 nm. A system directs the light at a frequency at or near 589 nm toward the celestial object and provides synthetic guide star generation.

  19. The Drifting Star

    Science.gov (United States)

    2008-04-01

    By studying in great detail the 'ringing' of a planet-harbouring star, a team of astronomers using ESO's 3.6-m telescope have shown that it must have drifted away from the metal-rich Hyades cluster. This discovery has implications for theories of star and planet formation, and for the dynamics of our Milky Way. ESO PR Photo 09a/08 ESO PR Photo 09a/08 Iota Horologii The yellow-orange star Iota Horologii, located 56 light-years away towards the southern Horologium ("The Clock") constellation, belongs to the so-called "Hyades stream", a large number of stars that move in the same direction. Previously, astronomers using an ESO telescope had shown that the star harbours a planet, more than 2 times as large as Jupiter and orbiting in 320 days (ESO 12/99). But until now, all studies were unable to pinpoint the exact characteristics of the star, and hence to understand its origin. A team of astronomers, led by Sylvie Vauclair from the University of Toulouse, France, therefore decided to use the technique of 'asteroseismology' to unlock the star's secrets. "In the same way as geologists monitor how seismic waves generated by earthquakes propagate through the Earth and learn about the inner structure of our planet, it is possible to study sound waves running through a star, which forms a sort of large, spherical bell," says Vauclair. The 'ringing' from this giant musical instrument provides astronomers with plenty of information about the physical conditions in the star's interior. And to 'listen to the music', the astronomers used one of the best instruments available. The observations were conducted in November 2006 during 8 consecutive nights with the state-of-the-art HARPS spectrograph mounted on the ESO 3.6-m telescope at La Silla. Up to 25 'notes' could be identified in the unique dataset, most of them corresponding to waves having a period of about 6.5 minutes. These observations allowed the astronomers to obtain a very precise portrait of Iota Horologii: its

  20. The physics of stars

    CERN Document Server

    Phillips, A C

    1999-01-01

    The Physics of Stars, Second Edition, is a concise introduction to the properties of stellar interiors and consequently the structure and evolution of stars. Strongly emphasising the basic physics, simple and uncomplicated theoretical models are used to illustrate clearly the connections between fundamental physics and stellar properties. This text does not intend to be encyclopaedic, rather it tends to focus on the most interesting and important aspects of stellar structure, evolution and nucleosynthesis. In the Second Edition, a new chapter on Helioseismology has been added, along with a list

  1. Atmospheres of central stars

    International Nuclear Information System (INIS)

    Hummer, D.G.

    1978-01-01

    The author presents a brief summary of atmospheric models that are of possible relevance to the central stars of planetary nebulae, and then discusses the extent to which these models accord with the observations of both nebulae and central stars. Particular attention is given to the significance of the very high Zanstra temperature implied by the nebulae He II lambda 4686 A line, and to the discrepancy between the Zanstra He II temperature and the considerably lower temperatures suggested by the appearance of the visual spectrum for some of these objects. (Auth.)

  2. Bp- and Ap-stars in the moving Scorpio-Centaurus cluster

    International Nuclear Information System (INIS)

    Klochkova, V.G.; Kopylov, I.M.; Kumajgorodskaya, R.N.

    1981-01-01

    Selection of member-stars of the Scorpio-Centaurus cluster is made in its north-eastern part. 34 Bp- and Ap-stars out of 170 members of the cluster are found. Percentage of Bp- and Ap-stars differs by a factor of 3-4 in different zones of the cluster. The age of stars in different zones is (4-12)x10 6 years. Average distances of stars are estimated (120-145 pc). Spectral characteristics as well as peculiarity type are defined for 17 Bp- and Ap-stars using high resolution spectra. Essential weakening of He1 lines and Mg2 lambda 4481 line is found [ru

  3. Probing neutron star physics using accreting neutron stars

    NARCIS (Netherlands)

    Patruno, A.

    2010-01-01

    We give an obervational overview of the accreting neutron stars systems as probes of neutron star physics. In particular we focus on the results obtained from the periodic timing of accreting millisecond X-ray pulsars in outburst and from the measurement of X-ray spectra of accreting neutron stars

  4. [Star anise poisoning in infants].

    Science.gov (United States)

    Minodier, P; Pommier, P; Moulène, E; Retornaz, K; Prost, N; Deharo, L

    2003-07-01

    Star anise is used as herbal tea, for the treatment of colicky pain in infants. It may cause neurological troubles. We report 2 cases of star anise poisoning in infants before 6 months of age. Star anise herbal tea was given by parents. Tremors or spasms, hypertonia, hyperexcitability with crying, nystagmus, and vomiting were observed. Contamination or adulteration of Chinese star anise (Illicium verum Hook), with Japanese star anise (Illicium religiosum) was proved in one child. Confusion or blending between Chinese and Japanese star anise may cause poisoning. Japanese star anise is a neurotoxic plant indeed, because it contains sesquiterpenic lactones. From November 2001, star anise products are theoretically prohibited in France, but they may be still available in some small groceries, or imported by families themselves.

  5. Kepler observations of Am stars

    DEFF Research Database (Denmark)

    Balona, L. A.; Ripepi, V.; Cantanzaro, G.

    2011-01-01

    We present an analysis of high-resolution spectra for two pulsating Am stars in the Kepler field. The stellar parameters derived in this way are important because parameters derived from narrow-band photometry may be affected by the strong metal lines in these stars. We analyse the Kepler time...... series of ten known Am stars and find that six of them clearly show δ Scuti pulsations. The other four appear to be non-pulsating. We derive fundamental parameters for all known pulsating Am stars from ground-based observations and also for the Kepler Am stars to investigate the location...... of the instability strip for pulsating Am stars. We find that there is not much difference between the Am-star instability strip and the δ Scuti instability strip. We find that the observed location of pulsating Am stars in the HR diagram does not agree with the location predicted from diffusion calculations. Based...

  6. ENERGY STAR Certified Imaging Equipment

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 2.0 ENERGY STAR Program Requirements for Imaging Equipment that are effective as of...

  7. Photometry of faint blue stars

    International Nuclear Information System (INIS)

    Kilkenny, D.; Hill, P.W.; Brown, A.

    1977-01-01

    Photometry on the uvby system is given for 61 faint blue stars. The stars are classified by means of the Stromgren indices, using criteria described in a previous paper (Kilkenny and Hill (1975)). (author)

  8. ENERGY STAR Certified Commercial Boilers

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 1.0 ENERGY STAR Program Requirements for Commercial Boilers that are effective as of...

  9. ENERGY STAR Certified Ceiling Fans

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 3.1 ENERGY STAR Program Requirements for Ceiling Fans that are effective as of April 1,...

  10. ENERGY STAR Certified Ventilating Fans

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 4.0 ENERGY STAR Program Requirements for Ventilating Fans that are effective as of...

  11. ENERGY STAR Certified Water Heaters

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 3.2 ENERGY STAR Program Requirements for Water Heaters that are effective April 16, 2015....

  12. Which of Kepler's Stars Flare?

    Science.gov (United States)

    Kohler, Susanna

    2017-12-01

    The habitability of distant exoplanets is dependent upon many factors one of which is the activity of their host stars. To learn about which stars are most likely to flare, a recent study examines tens of thousands of stellar flares observed by Kepler.Need for a Broader SampleArtists rendering of a flaring dwarf star. [NASAs Goddard Space Flight Center/S. Wiessinger]Most of our understanding of what causes a star to flare is based on observations of the only star near enough to examine in detail the Sun. But in learning from a sample size of one, a challenge arises: we must determine which conclusions are unique to the Sun (or Sun-like stars), and which apply to other stellar types as well.Based on observations and modeling, astronomers think that stellar flares result from the reconnection of magnetic field lines in a stars outer atmosphere, the corona. The magnetic activity is thought to be driven by a dynamo caused by motions in the stars convective zone.HR diagram of the Kepler stars, with flaring main-sequence (yellow), giant (red) and A-star (green) stars in the authors sample indicated. [Van Doorsselaere et al. 2017]To test whether these ideas are true generally, we need to understand what types of stars exhibit flares, and what stellar properties correlate with flaring activity. A team of scientists led by Tom Van Doorsselaere (KU Leuven, Belgium) has now used an enormous sample of flares observed by Kepler to explore these statistics.Intriguing TrendsVan Doorsselaere and collaborators used a new automated flare detection and characterization algorithm to search through the raw light curves from Quarter 15 of the Kepler mission, building a sample of 16,850 flares on 6,662 stars. They then used these to study the dependence of the flare occurrence rate, duration, energy, and amplitude on the stellar spectral type and rotation period.This large statistical study led the authors to several interesting conclusions, including:Flare star incidence rate as a a

  13. ENERGY STAR Certified Pool Pumps

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 1.1 ENERGY STAR Program Requirements for Pool Pumps that are effective as of February 15,...

  14. ENERGY STAR Certified Roof Products

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 3.0 ENERGY STAR Program Requirements for Roof Products that are effective as of July 1,...

  15. ENERGY STAR Certified Vending Machines

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 3.1 ENERGY STAR Program Requirements for Refrigerated Beverage Vending Machines that are...

  16. UX Ori-Type Stars

    Science.gov (United States)

    Grinin, V.

    2017-06-01

    The brief review of the properties of the UX Ori type stars is presented. A special attention is given to the results of the Crimean program of the multi-year photometric and polarimetric observations of these stars.

  17. ENERGY STAR Certified Commercial Dishwashers

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 2.0 ENERGY STAR Program Requirements for Commercial Dishwashers that are effective as of...

  18. ENERGY STAR Certified Enterprise Servers

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 2.1 ENERGY STAR Program Requirements for Enterprise Servers that are effective as of...

  19. ENERGY STAR Certified Commercial Griddles

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 1.2 ENERGY STAR Program Requirements for Commercial Griddles that are effective as of May...

  20. ENERGY STAR Certified Audio Video

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 3.0 ENERGY STAR Program Requirements for Audio Video Equipment that are effective as of...