scholarly journals Distinguishing collisions from low signal strength in static 802.11n wireless LANs

2011 ◽  
Author(s):  
Mingu Cho ◽  
Hakyung Jung ◽  
Shinhaeng Oh ◽  
Ted "Taekyoung" Kwon ◽  
Yanghee Choi
Keyword(s):  
Wireless Lans ◽  
Signal Strength

Low-dimensional signal-strength fingerprint-based positioning in wireless LANs

2014 ◽  
Vol 12 ◽  
pp. 100-114 ◽  
Author(s):  
Dimitris Milioris ◽  
George Tzagkarakis ◽  
Artemis Papakonstantinou ◽  
Maria Papadopouli ◽  
Panagiotis Tsakalides
Keyword(s):  
Wireless Lans ◽  
Signal Strength ◽  
Low Dimensional

A distributed access control method for wireless LANs in shadowing environments

2001 ◽  
Vol 84 (9) ◽  
pp. 16-26
Author(s):  
Tadao Saito ◽  
Hitoshi Aida ◽  
Terumasa Aoki ◽  
Soichiro Hidaka ◽  
Tredej Toranawigtrai ◽  
...  
Keyword(s):  
Access Control ◽  
Control Method ◽  
Wireless Lans ◽  
Distributed Access Control

Utility-Based Distributed Association Control Scheme with User Guidance for IEEE802.11 Wireless LANs

2015 ◽  
Vol E98.B (8) ◽  
pp. 1700-1714 ◽  
Author(s):  
Takahiro IWAMI ◽  
Irda ROSLAN ◽  
Yumi TAKAKI ◽  
Kyoko YAMORI ◽  
Chikara OHTA ◽  
...  
Keyword(s):  
Wireless Lans ◽  
Control Scheme ◽  
User Guidance ◽  
Distributed Association

Improved Contrast in Ultra-Low-Field MRI with Time-Dependent Bipolar Prepolarizing Fields: Theory and NMR Demonstrations

2013 ◽  
Vol 20 (3) ◽  
pp. 327-336 ◽  
Author(s):  
Jaakko O. Nieminen ◽  
Jens Voigt ◽  
Stefan Hartwig ◽  
Hans Jürgen Scheer ◽  
Martin Burghoff ◽  
...  
Keyword(s):  
Field Strength ◽  
Time Course ◽  
Signal Strength ◽  
Relaxation Rates ◽  
Resonance Imaging ◽  
New Approach ◽  
Spin Lattice ◽  
Low Field ◽  
Low Field Mri ◽  
Magnetic Resonance Imaging Mri

Abstract The spin-lattice (T1) relaxation rates of materials depend on the strength of the external magnetic field in which the relaxation occurs. This T1 dispersion has been suggested to offer a means to discriminate between healthy and cancerous tissue by performing magnetic resonance imaging (MRI) at low magnetic fields. In prepolarized ultra-low-field (ULF) MRI, spin precession is detected in fields of the order of 10-100 μT. To increase the signal strength, the sample is first magnetized with a relatively strong polarizing field. Typically, the polarizing field is kept constant during the polarization period. However, in ULF MRI, the polarizing-field strength can be easily varied to produce a desired time course. This paper describes how a novel variation of the polarizing-field strength and duration can optimize the contrast between two types of tissue having different T1 relaxation dispersions. In addition, NMR experiments showing that the principle works in practice are presented. The described procedure may become a key component for a promising new approach of MRI at ultra-low fields

KAJIAN KEKUATAN SINYAL RADIO (RSSI) XBEE DALAM RANGKA PEMASANGAN LANDSLIDE EARLY WARNING SYSTEM (LEWS) DI KABUPATEN GARUT, TASIKMALAYA DAN MAJALENGKA

2019 ◽  
Vol 3 (2) ◽  
pp. 88
Author(s):  
Riski Fitriani
Keyword(s):  
Early Warning ◽  
Early Warning System ◽  
Warning System ◽  
Signal Strength ◽  
Received Signal Strength ◽  
Received Signal Strength Indicator ◽  
Landslide Early Warning ◽  
Point To Point

Salah satu inovasi untuk menanggulangi longsor adalah dengan melakukan pemasangan Landslide Early Warning System (LEWS). Media transmisi data dari LEWS yang dikembangkan menggunakan sinyal radio Xbee. Sehingga sebelum dilakukan pemasangan LEWS, perlu dilakukan kajian kekuatan sinyal tersebut di lokasi yang akan terpasang yaitu Garut, Tasikmalaya, dan Majalengka. Kajian dilakukan menggunakan 2 jenis Xbee yaitu Xbee Pro S2B 2,4 GHz dan Xbee Pro S5 868 MHz. Setelah dilakukan kajian, Xbee 2,4 GHz tidak dapat digunakan di lokasi pengujian Garut dan Majalengka karena jarak modul induk dan anak cukup jauh serta terlalu banyak obstacle. Topologi yang digunakan yaitu topologi pair/point to point, dengan mengukur nilai RSSI menggunakan software XCTU. Semakin kecil nilai Received Signal Strength Indicator (RSSI) dari nilai receive sensitivity Xbee maka kualitas sinyal semakin baik. Pengukuran dilakukan dengan meninggikan antena Xbee dengan beberapa variasi ketinggian untuk mendapatkan kualitas sinyal yang lebih baik. Hasilnya diperoleh beberapa rekomendasi tinggi minimal antena Xbee yang terpasang di tiap lokasi modul anak pada 3 kabupaten.

Sign in / Sign up

Export Citation Format

Share Document