6 research outputs found
Voting Scheme Nearest Neighbors by Difference Distance Metrics Measurement
K-Nearest Neighbor (KNN) is a widely used method for both classification and regression cases. This algorithm, known for its simplicity and effectiveness, relies primarily on the Euclidean formula for distance metrics. Therefore, this study aimed to develop a voting model where observations were made using different distance calculation formulas. The nearest neighbors algorithm was divided based on differences in distance measurements, with each resulting model contributing a vote to determine the final class. Consequently, three methods were proposed, namely k-nearest neighbors (KNN), Local Mean-based KNN, and Distance-Weighted neighbor (DWKNN), with an inclusion of a voting scheme. The robustness of these models was tested using umbilical cord data characterized by imbalance and small dataset size. The results showed that the proposed voting model for nearest neighbors consistently improved performance by an average of 1-2% across accuracy, precision, recall, and F1 score when compared to the conventional non-voting method
Anomaly detection on flight route using similarity and grouping approach based-on automatic dependent surveillance-broadcast
Flight anomaly detection is used to determine the abnormal state data on the flight route. This study focused on two groups: general aviation habits (C1)and anomalies (C2). Groups C1 and C2 are obtained through similarity test with references. The methods used are: 1) normalizing the training data form, 2) forming the training segment 3) calculating the log-likelihood value and determining the maximum log-likelihood (C1) and minimum log-likelihood (C2) values, 4) determining the percentage of data based on criteria C1 and C2 by grouping SVM, KNN, and K-means and 5) Testing with log-likelihood ratio. The results achieved in each segment are Log-likelihood value in C1Latitude is -15.97 and C1Longitude is -16.97. On the other hand, Log-likelihood value in C2Latitude is -19.3 (maximum) and -20.3 (minimum), and log-likelihood value in C2Longitude is -21.2 (maximum) and -24.8 (minimum). The largest percentage value in C1 is 96%, while the largest in C2 is 10%. Thus, the highest potential anomaly data is 10%, and the smallest is 3%. Also, there are performance tests based on F-measure to get accuracy and precision
Design and testing of test rigs for fault detection in energy systems
This portfolio summarizes the development of an automated system capable of detecting operational faults within energy systems. The system includes water transport, heating and refrigeration. Multiple sensors monitor the sub-systems in the prototype. For example, when heating water, temperature was measured to identify deviations from a steady state value...Este portafolio resume el desarrollo de un sistema automatizado capaz de detectar fallas operacionales en sistemas energéticos. El sistema incluye transporte de agua, calentamiento y refrigeración. Múltiples sensores monitorean los subsistemas en el prototipo. Por ejemplo, al calentar agua, se midió la temperatura para identificar desviaciones de un valor en estado estable..
Dynamic spatial segmentation strategy based magnetic field indoor positioning system
In this day and age, it is imperative for anyone who relies on a mobile device to
track and navigate themselves using the Global Positioning System (GPS). Such
satellite-based positioning works as intended when in the outdoors, or when the
device is able to have unobstructed communication with GPS satellites.
Nevertheless, at the same time, GPS signal fades away in indoor environments due
to the effects of multi-path components and obstructed line-of-sight to the
satellite. Therefore, numerous indoor localisation applications have emerged in
the market, geared towards finding a practical solution to satisfy the need for
accuracy and efficiency.
The case of Indoor Positioning System (IPS) is promoted by recent smart devices,
which have evolved into a multimedia device with various sensors and optimised
connectivity. By sensing the device’s surroundings and inferring its context,
current IPS technology has proven its ability to provide stable and reliable indoor
localisation information. However, such a system is usually dependent on a high-density of infrastructure that requires expensive installations (e.g. Wi-Fi-based
IPS). To make a trade-off between accuracy and cost, considerable attention from
many researchers has been paid to the range of infrastructure-free technologies,
particularly exploiting the earth’s magnetic field (EMF).
EMF is a promising signal type that features ubiquitous availability, location
specificity and long-term stability. When considering the practicality of this
typical signal in IPS, such a system only consists of mobile device and the EMF
signal. To fully comprehend the conventional EMF-based IPS reported in the
literature, a preliminary experimental study on indoor EMF characteristics was
carried out at the beginning of this research. The results revealed that the positioning performance decreased when the presence of magnetic disturbance
sources was lowered to a minimum. In response to this finding, a new concept of
spatial segmentation is devised in this research based on magnetic anomaly (MA).
Therefore, this study focuses on developing innovative techniques based on spatial
segmentation strategy and machine learning algorithms for effective indoor
localisation using EMF.
In this thesis, four closely correlated components in the proposed system are
included: (i) Kriging interpolation-based fingerprinting map; (ii) magnetic
intensity-based spatial segmentation; (iii) weighted Naïve Bayes classification
(WNBC); (iv) fused features-based k-Nearest-Neighbours (kNN) algorithm.
Kriging interpolation-based fingerprinting map reconstructs the original observed
EMF positioning database in the calibration phase by interpolating predicted
points. The magnetic intensity-based spatial segmentation component then
investigates the variation tendency of ambient EMF signals in the new database to
analyse the distribution of magnetic disturbance sources, and accordingly,
segmenting the test site. Then, WNBC blends the exclusive characteristics of
indoor EMF into original Naïve Bayes Classification (NBC) to enable a more
accurate and efficient segmentation approach. It is well known that the best IPS
implementation often exerts the use of multiple positing sources in order to
maximise accuracy. The fused features-based kNN component used in the
positioning phase finally learns the various parameters collected in the calibration
phase, continuously improving the positioning accuracy of the system.
The proposed system was evaluated on multiple indoor sites with diverse layouts.
The results show that it outperforms state-of-the-art approaches and demonstrate
an average accuracy between 1-2 meters achieved in typical sites by the best
methods proposed in this thesis across most of the experimental environments. It
can be believed that such an accurate approach will enable the future of
infrastructure–free IPS technologies