Natural Joins for Schema-free Data

Author(s):  
Damjan Gjurovski ◽  
Sebastian Michel
Keyword(s):  
2008 ◽  
Author(s):  
Kristie Nemeth ◽  
Nicole Arbuckle ◽  
Andrea Snead ◽  
Drew Bowers ◽  
Christopher Burneka ◽  
...  

1998 ◽  
Vol 37 (11) ◽  
pp. 155-162 ◽  
Author(s):  
B. Maul-Kötter ◽  
Th. Einfalt

Continuous raingauge measurements are an important input variable for detailed rainfall-runoff simulation. In North Rhine-Westphalia, more than 150 continuous raingauges are used for local hydrological design through the use of site specific rainfall runoff models. Requiring gap-free data, the State Environmental Agency developed methods to use a combination of daily measurements and neighbouring continuous measurements for filling periods of lacking data in a given raindata series. The objective of such a method is to obtain plausible data for water balance simulations. For more than 3500 station years the described methodology has been applied.


2005 ◽  
Vol 21 (5) ◽  
pp. 1550-1556 ◽  
Author(s):  
Sandra Feitosa ◽  
Viviane Colares ◽  
Jimmy Pinkham

The aim of this study was to analyze the psychosocial effects of severe caries in 4-year-old children in Recife, Pernambuco, Brazil. The clinical examination was conducted by a single examiner in order to select children with severe caries and caries-free (kappa = 1). Of the 861 children examined, 77 (8.1%) had severe caries and 225 (23.6%) were caries-free. Data were collected by applying validated questionnaires answered by the parents or guardians. Most of the parents or guardians of children with severe caries reported that their children complained of toothache (72.7%), and a significant portion stated that their children had problems eating certain kinds of food (49.4%) and missed school (26.0%) because of their teeth. Most of the parents or guardians of children with severe caries (68.8%) stated that oral health affects their children's life, while the same was stated by 9.8% of the parents or guardians of the caries-free children. Severe caries was found to have a negative impact on children's oral health-related quality of life.


2018 ◽  
Vol 11 (1) ◽  
pp. 78 ◽  
Author(s):  
Yasmin M. Amin ◽  
Amr T. Abdel-Hamid

The IEEE 802.15.4 standard defines the PHY and MAC layer specifications for Low-Rate Wireless Personal Area Networks (LR-WPANs). With the proliferation of many time-critical applications with real-time delivery, low latency, and/or specific bandwidth requirements, Guaranteed Time Slots (GTS) are increasingly being used for reliable contention-free data transmission by nodes within beacon-enabled WPANs. To evaluate the performance of the 802.15.4 GTS management scheme, this paper introduces a new GTS simulation model for OMNeT++ / MiXiM. Our GTS model considers star-topology WPANs within the 2.4 GHz frequency band, and is in full conformance with the IEEE 802.15.4 – 2006 standard. To enable thorough investigation of the behaviors and impacts of different attacks against the 802.15.4 GTS mechanism, a new GTS attacks simulation model for OMNeT++ is also introduced in this paper. Our GTS attacks model is developed for OMNeT++ / NETA, and is integrated with our GTS model to provide a single inclusive OMNeT++ simulation model for both the GTS mechanism and all known-to-date attacks against it.


2008 ◽  
Vol 22 (1) ◽  
pp. 135-144 ◽  
Author(s):  
Daniele Posenato ◽  
Francesca Lanata ◽  
Daniele Inaudi ◽  
Ian F.C. Smith

2011 ◽  
Vol 3 (2) ◽  
pp. 139-145 ◽  
Author(s):  
Srdjan Glisic ◽  
J. Christoph Scheytt ◽  
Yaoming Sun ◽  
Frank Herzel ◽  
Ruoyu Wang ◽  
...  

A fully integrated transmitter (TX) and receiver (RX) front-end chipset, produced in 0.25 µm SiGe:C bipolar and complementary metal oxide semiconductor (BiCMOS) technology, is presented. The front-end is intended for high-speed wireless communication in the unlicensed ISM band of 9 GHz around 60 GHz. The TXand RX features a modified heterodyne topology with a sliding intermediate frequency. The TX features a 12 GHz in-phase and quadrature (I/Q) mixer, an intermediate frequency (IF) amplifier, a phase-locked loop, a 60 GHz mixer, an image-rejection filter, and a power amplifier. The RX features a low-noise amplifier (LNA), a 60 GHz mixer, a phase-locked loop (PLL), and an IF demodulator. The measured 1-dB compression point at the TX output is 12.6 dBm and the saturated power is 16.2 dBm. The LNA has measured noise figure of 6.5 dB at 60 GHz. Error-free data transmission with a 16 quadrature amplitude modulation (QAM) orthogonal frequency-division multiplexing (OFDM) signal and data rate of 3.6 Gbit/s (without coding 4.8 Gbit/s) over 15 m was demonstrated. This is the best reported result regarding both the data rate and transmission distance in SiGe and CMOS without beamforming.


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