2,458 research outputs found
Practical Accuracy Limits of Radiation-Aware Magneto-Inductive 3D Localization
The key motivation for the low-frequency magnetic localization approach is
that magnetic near-fields are well predictable by a free-space model, which
should enable accurate localization. Yet, limited accuracy has been reported
for practical systems and it is unclear whether the inaccuracies are caused by
field distortion due to nearby conductors, unconsidered radiative propagation,
or measurement noise. Hence, we investigate the practical performance limits by
means of a calibrated magnetoinductive system which localizes an active
single-coil agent with arbitrary orientation, using 4 mW transmit power at 500
kHz. The system uses eight single-coil anchors around a 3m x 3m area in an
office room. We base the location estimation on a complex baseband model which
comprises both reactive and radiative propagation. The link coefficients, which
serve as input data for location estimation, are measured with a multiport
network analyzer while the agent is moved with a positioner device. This
establishes a reliable ground truth for calibration and evaluation. The system
achieves a median position error of 3.2 cm and a 90th percentile of 8.3 cm.
After investigating the model error we conjecture that field distortion due to
conducting building structures is the main cause of the performance bottleneck.
The results are complemented with predictions on the achievable accuracy in
more suitable circumstances using the Cram\'er-Rao lower bound.Comment: To appear at the IEEE ICC 2019 Workshops. This work has been
submitted to the IEEE for possible publication. Copyright may be transferred
without notice, after which this version may no longer be accessibl
Tahap penguasaan, sikap dan minat pelajar Kolej Kemahiran Tinggi MARA terhadap mata pelajaran Bahasa Inggeris
Kajian ini dilakukan untuk mengenal pasti tahap penguasaan, sikap dan minat pelajar
Kolej Kemahiran Tinggi Mara Sri Gading terhadap Bahasa Inggeris. Kajian yang
dijalankan ini berbentuk deskriptif atau lebih dikenali sebagai kaedah tinjauan. Seramai
325 orang pelajar Diploma in Construction Technology dari Kolej Kemahiran Tinggi
Mara di daerah Batu Pahat telah dipilih sebagai sampel dalam kajian ini. Data yang
diperoleh melalui instrument soal selidik telah dianalisis untuk mendapatkan
pengukuran min, sisihan piawai, dan Pekali Korelasi Pearson untuk melihat hubungan
hasil dapatan data. Manakala, frekuensi dan peratusan digunakan bagi mengukur
penguasaan pelajar. Hasil dapatan kajian menunjukkan bahawa tahap penguasaan
Bahasa Inggeris pelajar adalah berada pada tahap sederhana manakala faktor utama yang
mempengaruhi penguasaan Bahasa Inggeris tersebut adalah minat diikuti oleh sikap.
Hasil dapatan menggunakan pekali Korelasi Pearson juga menunjukkan bahawa terdapat
hubungan yang signifikan antara sikap dengan penguasaan Bahasa Inggeris dan antara
minat dengan penguasaan Bahasa Inggeris. Kajian menunjukkan bahawa semakin positif
sikap dan minat pelajar terhadap pengajaran dan pembelajaran Bahasa Inggeris semakin
tinggi pencapaian mereka. Hasil daripada kajian ini diharapkan dapat membantu pelajar
dalam meningkatkan penguasaan Bahasa Inggeris dengan memupuk sikap positif dalam
diri serta meningkatkan minat mereka terhadap Bahasa Inggeris dengan lebih baik. Oleh
itu, diharap kajian ini dapat memberi panduan kepada pihak-pihak yang terlibat dalam
membuat kajian yang akan datang
Twins:Device-free Object Tracking using Passive Tags
Without requiring objects to carry any transceiver, device-free based object
tracking provides a promising solution for many localization and tracking
systems to monitor non-cooperative objects such as intruders. However, existing
device-free solutions mainly use sensors and active RFID tags, which are much
more expensive compared to passive tags. In this paper, we propose a novel
motion detection and tracking method using passive RFID tags, named Twins. The
method leverages a newly observed phenomenon called critical state caused by
interference among passive tags. We contribute to both theory and practice of
such phenomenon by presenting a new interference model that perfectly explains
this phenomenon and using extensive experiments to validate it. We design a
practical Twins based intrusion detection scheme and implement a real prototype
with commercial off-the-shelf reader and tags. The results show that Twins is
effective in detecting the moving object, with low location error of 0.75m in
average
Orientation-Aware 3D SLAM in Alternating Magnetic Field from Powerlines
Identifying new sensing modalities for indoor localization is an interest of research. This paper studies powerline-induced alternating magnetic field (AMF) that fills the indoor space for the orientation-aware three-dimensional (3D) simultaneous localization and mapping (SLAM). While an existing study has adopted a uniaxial AMF sensor for SLAM in a plane surface, the design falls short of addressing the vector field nature of AMF and is therefore susceptible to sensor orientation variations. Moreover, although the higher spatial variability of AMF in comparison with indoor geomagnetism promotes location sensing resolution, extra SLAM algorithm designs are needed to achieve robustness to trajectory deviations from the constructed map. To address the above issues, we design a new triaxial AMF sensor and a new SLAM algorithm that constructs a 3D AMF intensity map regularized and augmented by a Gaussian process. The triaxial sensor’s orientation estimation is free of the error accumulation problem faced by inertial sensing. From extensive evaluation in eight indoor environments, our AMF-based 3D SLAM achieves sub-1m to 3m median localization errors in spaces of up to 500 m2 , sub-2° mean error in orientation sensing, and outperforms the SLAM systems based on Wi-Fi, geomagnetism, and uniaxial AMF by more than 30%
Fuzzy classifier ensembles for hierarchical WiFi-based semantic indoor localization
The number of applications for smartphones and tablets is growing exponentially in the last years. Many of these applications are supported by the so-called Location Based Services, which are expected to provide reliable real-time localization anytime and anywhere, no matter either outdoors or indoors. Even though outdoors world-wide localization has been successfully developed through the well-known Global Navigation Satellite System technology, its counterpart large-scale deployment indoors is not available yet. In previous work, we have already introduced a novel technology for indoor localization supported by a WiFi fingerprint approach. In this paper, we describe how to enhance such approach through the combination of hierarchical localization and fuzzy classifier ensembles. It has been tested and validated at the University of Edinburgh, yielding promising results.Ministerio de Economía y CompetitividadXunta de Galici
Decision Agriculture
In this chapter, the latest developments in the field of decision agriculture are discussed. The practice of management zones in digital agriculture is described for efficient and smart faming. Accordingly, the methodology for delineating management zones is presented. Modeling of decision support systems is explained along with discussion of the issues and challenges in this area. Moreover, the precision agriculture technology is also considered. Moreover, the chapter surveys the state of the decision agriculture technologies in the countries such as Bulgaria, Denmark, France, Israel, Malaysia, Pakistan, United Kingdom, Ukraine, and Sweden. Finally, different field factors such as GPS accuracy and crop growth are also analyzed
Current Advances in Internet of Underground Things
The latest developments in Internet of Underground Things are covered in this chapter. First, the IOUT Architecture is discussed followed by the explanation of the challenges being faced in this paradigm. Moreover, a comprehensive coverage of the different IOUT components is presented that includes communications, sensing, and system integration with the cloud. An in-depth coverage of the applications of the IOUT in various disciplines is also surveyed. These applications include areas such as decision agriculture, pipeline monitoring, border control, and oil wells
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