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Total 1478 results found since Jan 2013.

Sensors, Vol. 19, Pages 312: Real-Time Model-Free Minimum-Seeking Autotuning Method for Unmanned Aerial Vehicle Controllers Based on Fibonacci-Search Algorithm
Saska The paper presents a novel autotuning approach for finding locally-best parameters of controllers on board of unmanned aerial vehicles (UAVs). The controller tuning is performed fully autonomously during flight on the basis of predefined ranges of controller parameters. Required controller properties may be simply interpreted by a cost function, which is involved in the optimization process. For example, the sum of absolute values of the tracking error samples or performance indices, including weighed functions of control signal samples, can be penalized to achieve very precise position control, if required. The...
Source: Sensors - January 14, 2019 Category: Biotechnology Authors: Wojciech Giernacki Dariusz Horla Tom áš Báča Martin Saska Tags: Article Source Type: research

Sensors, Vol. 19, Pages 652: An Appearance-Based Tracking Algorithm for Aerial Search and Rescue Purposes
rmingol The automation of the Wilderness Search and Rescue (WiSAR) task aims for high levels of understanding of various scenery. In addition, working in unfriendly and complex environments may cause a time delay in the operation and consequently put human lives at stake. In order to address this problem, Unmanned Aerial Vehicles (UAVs), which provide potential support to the conventional methods, are used. These vehicles are provided with reliable human detection and tracking algorithms; in order to be able to find and track the bodies of the victims in complex environments, and a robust control system to maintain saf...
Source: Sensors - February 5, 2019 Category: Biotechnology Authors: Abdulla Al-Kaff Mar ía José Gómez-Silva Francisco Miguel Moreno Arturo de la Escalera Jos é María Armingol Tags: Article Source Type: research

Sensors, Vol. 19, Pages 734: Multi-UAV Reconnaissance Task Assignment for Heterogeneous Targets Based on Modified Symbiotic Organisms Search Algorithm
Yang This paper considers a reconnaissance task assignment problem for multiple unmanned aerial vehicles (UAVs) with different sensor capacities. A modified Multi-Objective Symbiotic Organisms Search algorithm (MOSOS) is adopted to optimize UAVs’ task sequence. A time-window based task model is built for heterogeneous targets. Then, the basic task assignment problem is formulated as a Multiple Time-Window based Dubins Travelling Salesmen Problem (MTWDTSP). Double-chain encoding rules and several criteria are established for the task assignment problem under logical and physical constraints. Pareto domina...
Source: Sensors - February 12, 2019 Category: Biotechnology Authors: Hao-Xiang Chen Ying Nan Yi Yang Tags: Article Source Type: research

Sensors, Vol. 19, Pages 3542: Unsupervised Human Detection with an Embedded Vision System on a Fully Autonomous UAV for Search and Rescue Operations
Gasteratos Unmanned aerial vehicles (UAVs) play a primary role in a plethora of technical and scientific fields owing to their wide range of applications. In particular, the provision of emergency services during the occurrence of a crisis event is a vital application domain where such aerial robots can contribute, sending out valuable assistance to both distressed humans and rescue teams. Bearing in mind that time constraints constitute a crucial parameter in search and rescue (SAR) missions, the punctual and precise detection of humans in peril is of paramount importance. The paper in hand deals with real-time human...
Source: Sensors - August 13, 2019 Category: Biotechnology Authors: Eleftherios Lygouras Nicholas Santavas Anastasios Taitzoglou Konstantinos Tarchanidis Athanasios Mitropoulos Antonios Gasteratos Tags: Article Source Type: research

Sensors, Vol. 19, Pages 4526: Mobile Phone Passive Positioning through the Detection of Uplink Signals for Search and Rescue
Sun Li To satisfy the service requirements of high accuracy and efficient life detection and location for search and rescue (SAR) missions after a disaster, we developed a passive positioning method to locate mobile phones by capturing the random access preamble, which can be applied to fourth-generation (4G) and even fifth-generation (5G) communication systems. We analyzed the characteristics of the random access procedure of a communication system and established a way to detect mobile phones by combining the time-difference-of-arrival (TDOA) estimation to determine the location. Then, we performed an experiment ...
Source: Sensors - October 16, 2019 Category: Biotechnology Authors: Gao Deng Zhang Sun Li Tags: Article Source Type: research

Sensors, Vol. 19, Pages 5192: Efficient Kernel-Based Subsequence Search for Enabling Health Monitoring Services in IoT-Based Home Setting
ssina This paper presents an efficient approach for subsequence search in data streams. The problem consists of identifying coherent repetitions of a given reference time-series, also in the multivariate case, within a longer data stream. The most widely adopted metric to address this problem is Dynamic Time Warping (DTW), but its computational complexity is a well-known issue. In this paper, we present an approach aimed at learning a kernel approximating DTW for efficiently analyzing streaming data collected from wearable sensors, while reducing the burden of DTW computation. Contrary to kernel, DTW allows for compari...
Source: Sensors - November 26, 2019 Category: Biotechnology Authors: Antonio Candelieri Stanislav Fedorov Enza Messina Tags: Article Source Type: research

Sensors, Vol. 20, Pages 223: A Variational Stacked Autoencoder with Harmony Search Optimizer for Valve Train Fault Diagnosis of Diesel Engine
g Zhang Diesel engine fault diagnosis is vital due to enhanced reliability and economic efficiency requirements. The extracted features in traditional fault diagnosis are constructed manually, which is very cumbersome because of the requirement for lots of expertise. To handle this issue, this paper proposed a variational stacked autoencoder (VSAE) to adaptively extract features from angular domain signals. As an unsupervised algorithm, VSAE can extract high-level features with the help of multiple encoding layers. Layer-wise pre-training and fine-tuning are introduced to get a better network initialization value. M...
Source: Sensors - December 30, 2019 Category: Biotechnology Authors: Chen Mao Zhao Jiang Zhang Tags: Article Source Type: research

Sensors, Vol. 20, Pages 1469: Wrist Vascular Biometric Recognition Using a Portable Contactless System
llo Human wrist vein biometric recognition is one of the least used vascular biometric modalities. Nevertheless, it has similar usability and is as safe as the two most common vascular variants in the commercial and research worlds: hand palm vein and finger vein modalities. Besides, the wrist vein variant, with wider veins, provides a clearer and better visualization and definition of the unique vein patterns. In this paper, a novel vein wrist non-contact system has been designed, implemented, and tested. For this purpose, a new contactless database has been collected with the software algorithm TGS-CVBR®....
Source: Sensors - March 6, 2020 Category: Biotechnology Authors: Raul Garcia-Martin Raul Sanchez-Reillo Tags: Article Source Type: research

Sensors, Vol. 20, Pages 1862: A Novel Fuzzy PID Congestion Control Model Based on Cuckoo Search in WSNs
her Ali Wireless Sensor Networks (WSNs) consist of multiple sensor nodes, each of which has the ability to collect, receive and send data. However, irregular data sources can lead to severe network congestion. To solve this problem, the Proportional Integral Derivative (PID) controller is introduced into the congestion control mechanism to control the queue length of messages in nodes. By running the PID algorithm on cluster head nodes, the effective collection of sensor data is realized. In addition, a fuzzy control algorithm is proposed to solve the problems of slow parameter optimization, limited adaptive ability an...
Source: Sensors - March 26, 2020 Category: Biotechnology Authors: Lin Lin You Shi Jinfu Chen Sher Ali Tags: Article Source Type: research

Sensors, Vol. 20, Pages 3509: Wireless Sensor Networks Fault-Tolerance Based on Graph Domination with Parallel Scatter Search
l-Sayed In wireless sensor/ad hoc networks, all wireless nodes frequently flood the network channel by transmitting control messages causing “broadcast storm problem”. Thus, inspired by the physical backbone in wired networks, a Virtual Backbone (VB) in wireless sensor/ad hoc networks can help achieve efficient broadcasting. A well-known and well-researched approach for constructing virtual backbone is solving the Connected Dominating Set (CDS) problem. Furthermore, minimizing the size of the CDS is a significant research issue. We propose a new parallel scatter search algorithm with elite a...
Source: Sensors - June 20, 2020 Category: Biotechnology Authors: Abdel-Rahman Hedar Shada N. Abdulaziz Emad Mabrouk Gamal A. El-Sayed Tags: Article Source Type: research

Sensors, Vol. 20, Pages 3697: Hyperparameter Optimization Method Based on Harmony Search Algorithm to Improve Performance of 1D CNN Human Respiration Pattern Recognition System
In this study, we propose a method to find an optimal combination of hyperparameters to improve the accuracy of respiration pattern recognition in a 1D (Dimensional) convolutional neural network (CNN). The proposed method is designed to integrate with a 1D CNN using the harmony search algorithm. In an experiment, we used the depth of the convolutional layer of the 1D CNN, the number and size of kernels in each layer, and the number of neurons in the dense layer as hyperparameters for optimization. The experimental results demonstrate that the proposed method provided a recognition rate for five respiration patterns of appr...
Source: Sensors - June 30, 2020 Category: Biotechnology Authors: Seong-Hoon Kim Zong Woo Geem Gi-Tae Han Tags: Article Source Type: research

Sensors, Vol. 20, Pages 5223: AiRobSim: Simulating a Multisensor Aerial Robot for Urban Search and Rescue Operation and Training
In this study, we developed a framework, AiRobSim, to simulate an aerial robot to acquire both aboveground and underground information for post-disaster SaR. The integration of UAV, ground-penetrating radar (GPR), and other sensors, such as global navigation satellite system (GNSS), inertial measurement unit (IMU), and cameras, enables the aerial robot to provide a holistic view of the complex urban disaster areas. The robot-collected data can help locate critical spaces under the rubble to save trapped victims. The simulation framework can serve as a virtual training platform for novice users to control and operate the ro...
Source: Sensors - September 12, 2020 Category: Biotechnology Authors: Chen Li Liu Li Tags: Article Source Type: research

Sensors, Vol. 20, Pages 5279: Hybrid Attention Network for Language-Based Person Search
Xiao Language-based person search retrieves images of a target person using natural language description and is a challenging fine-grained cross-modal retrieval task. A novel hybrid attention network is proposed for the task. The network includes the following three aspects: First, a cubic attention mechanism for person image, which combines cross-layer spatial attention and channel attention. It can fully excavate both important midlevel details and key high-level semantics to obtain better discriminative fine-grained feature representation of a person image. Second, a text attention network for language description...
Source: Sensors - September 14, 2020 Category: Biotechnology Authors: Li Xu Xiao Tags: Article Source Type: research

Sensors, Vol. 21, Pages 1764: Multi-Layer and Conformally Integrated Structurally Embedded Vascular Antenna (SEVA) Arrays
egory H. Huff This work presents the design and fabrication of two multi-element structurally embedded vascular antennas (SEVAs). These are achieved through advances in additively manufactured sacrificial materials and demonstrate the ability to embed vascular microchannels in both planar and complex-curved epoxy-filled quartz fiber structural composite panels. Frequency-reconfigurable antennas are formed by these structures through the pressure-driven transport of liquid metal through the embedded microchannels. The planar multi-layer topology examines the ability to fabricate two co-located radiating structures separ...
Source: Sensors - March 4, 2021 Category: Biotechnology Authors: Amrita Bal Jeffery W. Baur Darren J. Hartl Geoffrey J. Frank Thao Gibson Hong Pan Gregory H. Huff Tags: Article Source Type: research

Sensors, Vol. 21, Pages 6568: Motion-Encoded Electric Charged Particles Optimization for Moving Target Search Using Unmanned Aerial Vehicles
This study is directly applicable to a real-world scenario, for instance the movement of a misplaced animal can be detected and subsequently its location can be transmitted to its caretaker. Using Bayesian theory, finding the location of a moving target is formulated as an optimization problem wherein the objective function is to maximize the probability of detecting the target. In the proposed ECPO-ME algorithm, the search trajectory is encoded as a series of UAV motion paths. These paths evolve in each iteration of the ECPO-ME algorithm. The performance of the algorithm is tested for six different scenarios with differen...
Source: Sensors - September 30, 2021 Category: Biotechnology Authors: Mohammed A. Alanezi Houssem R. E. H. Bouchekara Mohammad S. Shahriar Yusuf A. Sha ’aban Muhammad S. Javaid Mohammed Khodja Tags: Article Source Type: research