esa-sceva/satcom-chunk-collection huggingface dataset:
## 5 Conclusions  
We proposed a simple method of enhancing gain in a linear microstrip patch array antenna by appending two metallic plates on the array axis along with adjustment of the tilting angle and the length of the metallic plates for 24 GHz radar applications. First, an inset-fed microstrip square patch antenna with a 100 \(\Omega\) microstrip feed line, which is used as an element for a 4 \(\times\) 1 microstrip patch array antenna, was designed to cover the 24.0-24.25 GHz frequency range on an HF-350F substrate.  
Next, 4 \(\times\) 1 shunt-connected series feed networks using uniform power distribution with a power ratio of 1:1:1:1 and tapered power distribution with a power ratio of 1:5:5:1 were designed. Their performance as a power divider was validated through a comparison of the theoretical and simulated results. The input reflection coefficients, realized gain, and radiation patterns of the 4 \(\times\) 1 microstrip square patch array antennas combined with shunt-connected series feed networks using uniform and tapered power distributions were compared. Maximum gain of the 4 \(\times\) 1 array antenna with the tapered power distribution decreased 0.53 dB with an increased HPBW, but the sidelobe level of the z-x plane was reduced by 7.9 dB.  
Two metallic plates were appended along the array axis to increase gain in the 4 \(\times\) 1 patch array antenna using the tapered power distribution. The effects on the array antenna performance from the tilting angle and the length of the metallic plates were investigated. We found that maximum gain was highest when the tilting angle was around 70\({}^{\circ}\), and it increased gradually as the length of the two metallic plates increased. To achieve 7 dB gain enhancement (doubling the maximum detection range), a metallic plate length of 50 mm was selected.  
Measured maximum gain of the 4 \(\times\) 1 patch array antenna using the tapered power distribution without metallic plates was 9.8 dBi at 24.125 GHz, whereas the measured maximum gain of the antenna appended with metallic plates was 16.8 dBi. Therefore, a 7 dB gain enhancement can be achieved by adding two metallic plates along the array axis.  
Maximum gain might be slightly enhanced by appending two more metallic plates along the axis perpendicular to the array to surround the whole four sides of the array antenna, but the cost and complexity of the fabrication might be considerably increased.  
The proposed method can be applied to various radar and millimeter wave applications. It can also be used for satellite communications and future mobile communication systems (5G and 6G). In future work, we plan to conduct research on the production of integrated antennas by using 3D printers.  
[PERSON] contributed the idea, the simulation, the analysis, and the overall research. [PERSON]-I.L. contributed fabrications and measurements. All authors have read and agreed to the published version of the manuscript.  
This research was supported by Daegu University Research Grant 2019.  
**Data Availability Statement:** Not applicable.  
The authors declare they have no conflict of interest.
## 1 Introduction
### Scope and Contribution of This Study  
Focusing on multi-span and multi-disc rotors, two novel algorithms, called SDA and TODA, are proposed based on the continuous rotor dynamic analysis method (CRDMM) in this paper to realize rotor unbalance identification without excitation or test runs. These algorithms have the flexibility to incorporate any number of bearings and discs. The equations of the inverse problem, which are developed based on CRDMM using unbalance responses as inputs, cannot be directly solved to obtain rotor unbalances as the equationsare non-linear transcendental and there are too many unknown variables. Moreover, rotor unbalances and bearing coefficients are coupled together. A matrix method is proposed to solve the problem and identify rotor unbalance from unbalance responses. Four kinds of numerical simulations considering sensor resolutions and measurement errors are conducted for the validation. The adjustment point, which can greatly improve identification accuracy, is found by means of simulations. Proper sensor resolutions are recommended for engineering applications.  
Compared with the methods described in references [14; 35; 36], SDA and TODA do not require test runs or external exciters. Compared with other existing methods in the literature, SDA and TODA can be applied to rotors with any number of bearings and any number of discs. Moreover, SDA and TODA can not only be used for rotors with rolling bearings but also for rotors supported by oil journal bearings. The proposed methods provide a technique for on-line monitoring of the rotor unbalances of multi-bearing and multi-disc rotors without using test runs or external exciters.
# An Energy Aware Adaptive Sampling Algorithm for Energy Harvesting WSN with Energy Hungry Sensors
## 1 Introduction
The platform is equipped with a micro wind generator for harvesting energy from the wind [8]. In the second deployment (II), data are collected with an off the shelf platform, interfaced with power hungry gas sensors used to monitor the conditions within a beehive [9]. This platform uses a solar panel to harvest energy from the sun and five different gas sensors that require long warm up periods. Detailed analysis and measurement of the energy consumption of the embedded systems are performed with the same firmware implemented on the deployments. This allows identification of the energy consumed by the system during various active states and replication of the in-field system behavior. In this way, a precise energy model is developed that is later used in the simulations. The proposed algorithm is implemented in MATLAB using the real sensor power consumption and the harvested energy collected from the two deployments. This allows comparison with the traditional adaptive sampling algorithm to be done [6]. The contributions of this paper are as follows:  
* An energy aware ASA optimized for energy harvesting nodes achieving self-sustainability with power hungry sensors is presented. * Precise energy model for a WSN network with power-hungry sensors and energy harvesting capabilities. * Evaluation of the proposed approach within two application domains, namely SHM and monitoring of beehives. * Simulation evaluation using long term in-field measurements and comparison with the ASA (without energy awareness) and the fixed sampling rate (conventional method) in terms of energy durability.
# Can Urban Environmental Problems Be Accurately Identified? A Complaint Text Mining Method
## 2 Materials and Methods
### Data Collection and Methods  
#### 2.2.1 Data Collection and Pre-Processing  
The two-year data (from 1 March 2018 to 31 March 2020) were retrieved from the website of the Guangzhou Municipal Ecological Environment Bureau ([[http://sthji.gz.gov.cn/ztlm/tsibzx/](http://sthji.gz.gov.cn/ztlm/tsibzx/)]([http://sthji.gz.gov.cn/ztlm/tsibzx/](http://sthji.gz.gov.cn/ztlm/tsibzx/)), accessed on 31 March 2020). The complaints datasets contain the date, complaint ID, district and address, firms, topic of complaint, complaint content, government response, and response date (Table 1). We obtained 5672 valid records with missing geographic information, and unidentified complaint content was excluded.  
Figure 1: Location of environmental complaints in Guangzhou city (March 2018–March 2020).  
The 5672 complaint records were classified into six categories, including air, water, noise, waste, electromagnetic radiation (EM radiation), and light based on the topic of complaint (Table 2). Most complaints in all districts regard air pollution, follows by noise, while the categories with the smallest number of complaints are EM radiation and light. The Baiyun district has the largest number of complaints (1174), while the Conghua district has the fewest (157).  
\begin{table}
\begin{tabular}{c c  
Figure 2 describes the text mining process framework for Chinese environmental complaints. For the sake of content analysis and text mining, we cleaned the collected text data, including removing non-text data (punctuation marks, emoticons, and meaningless symbols), invalid characters (letters and numbers), and meaningless text (function words and pronouns). We removed the meaningless text by using some open-source Chinese stop word dictionaries (e.g., Harbin Institute of Technology (HIT) stop words and Baidu TM stop words). Then, we carried out data processing, including keyword extraction, sentiment analysis, and semantic network analysis.
## 4 Simulation and Model Experiment Validation
### Experimental Results for Battery Module Voltage Control Loop  
For the test of battery module voltage control loop, the reference output voltage for each battery module was changed suddenly from 10 V (V\({}_{\text{MX1-DC-ref}}\) = V\({}_{\text{MX2-DC-ref}}\) = V\({}_{\text{MX3-DC-ref}}\) = 10 V under steady-state operation) to V\({}_{\text{MX1-DC-ref}}\) = 13 V, V\({}_{\text{MX2-DC-ref}}\) = 9 V and V\({}_{\text{MX3-DC-ref}}\) = 8 V. The simulation results and experimental results are shown in Figure 9.  
From Figure 9, it can be observed that once the reference voltage values were changed, the output voltage of battery module 1 was controlled to increase while the output voltages of battery modules 2 and 3 were controlled to decrease. In Figure 9, the simulation model results and the hardware experimental results are in good agreement. In other words, the shape, magnitude, and overshoot/undershoot of the waveforms of simulation and hardware experiments match each other, which validates the small-signal model for the battery module voltage loop.
## 3 Wireless Localization Technology
### Hybrid Techniques  
While both technologies have distinct properties, there is a growing research effort to integrate the two groups. It aims to leverage their unique strengths and weaknesses to complement each other effectively. When combining various technologies, it is possible to categorize the approach into tightly coupled and loosely coupled based on the interdependencies between the technologies [9]. The tightly coupled approach involves closely integrating various technologies and data sources to achieve a high level of synergy. In positioning technology, this means that each technology simultaneously utilizes the data of others, complementing each other to achieve high accuracy. For example, enhanced Cell-ID is a technology that improves accuracy by adding RTT and AoA information between the anchor and the device to the Cell-ID method. On the other hand, the loosely coupled approach indicates that components operate independently, integrating information only when necessary. In positioning technology, this means that each technology independently measures location data, which is selectively and appropriately corrected depending on the situation. For instance, there are technologies that combine fingerprinting and PDR [10], which resolve the error of judging the reference location unrelated to the device's position and the cumulative error of the inertial navigation device due to the flow of time, as the device's position. Depending on the circumstances, a suitable combination between these two approaches can enhance positioning accuracy.
## 4 Results and Discussion
### Orbit Comparison
With respect to the AIUB solution as reference, which can be considered a particularly reliable reference due to its K-band validation [69], WEGC orbits compare better than UCAR (WEGC-NC 1.5 cm, WEGC-BC 4.3 cm, WEGC-BI 4.7 cm; UCAR 6.5 cm). _Metop._ In principle, a similar characteristics of the comparison results is found for both Metop satellites. Apart from the WEGC-BI solution, best agreement is found against WEGC-NC with an RMS of about 4.0 cm and 4.2 cm for Metop-A and Metop-B, respectively. Individual days of the comparison are slightly exceeding the 5 cm threshold, and furthermore days with increased differences against UCAR can be observed in August and September leading to an overall RMS close to and slightly exceeding 5 cm for Metop-A and Metop-B, respectively. These findings are consistent with earlier results from orbit inter-comparison for Metop [28]. Note that both Metop satellites undergo a maneuver in the considered period. Additionally, two days with missing attitude from CDAAC remain currently unprocessed. Finally we note that in general all orbit solutions for the presented missions (including those from UCAR, EUMETSAT, and AIUB) satisfy the introduced RO-application-oriented target specification of 5 cm in position and 0.05 mm/s in velocity.
## 2 Materials and Methods
### Volatile Compound Analysis  
The volatile compounds in Yulu were analyzed using HS-SPME-GC-MS [14]. Briefly, after addition of internal standard 2,4,6-trimethylpyridine (100 \(\upmu\)L and 50 mg/L), the liquid Yulu (5.0 g) was put into the headspace vial and incubated for 10 min at 300 r/min and 60 \({}^{\circ}\)C. The HS-SPME was carried out using the DVB-PDMS extraction needle at 300 r/min and 60 \({}^{\circ}\)C for 40 min. The volatile compounds were determined on the HP-INNOWAX column (60 m \(\times\) 0.25 mm \(\times\) 0.25 \(\upmu\)m) via the 7890-5977 GC-MS system (Agilent, Santa Clara, CA, USA). The carrier gas was helium at 1.2 mL/min in the splitless mode. GC-MS was conducted as follows: 40 \({}^{\circ}\)C for 5 min, 40-240 \({}^{\circ}\)C at 5 \({}^{\circ}\)C /min, 240-250 \({}^{\circ}\)C at 10 \({}^{\circ}\)C /min, and 250 \({}^{\circ}\)C for 6 min. The ion source and quadrupole temperature was set to 230 \({}^{\circ}\)C and 150 \({}^{\circ}\)C, respectively. The scan range was a full scan of 29-450 Da. After identification in the NIST database (v17.0) using AMDIS, the concentration of each volatile compound (\(C_{x}\)) was calculated according to the following equation:  
\[C_{x}=\frac{A_{x}\times M_{i}}{A_{i}\times M_{Y}}\]  
where, \(C_{x}\) is the concentration of each volatile compound (mg/kg), \(A_{x}\) is the peak area of each volatile compound, \(A_{i}\) is the peak area of 2,4,6-trimethylpyridine, \(M_{i}\) is the weight of 2,4,6-trimethylpyridine (\(\mathrm{\SIUnitSymbolMicro g}\)), and \(M_{Y}\) is the weight of Yulu (g).
# Optimization of Redundant Degrees of Freedom in Robotic Flat-End Milling Based on Dynamic Response
###### Abstract  
With the advantages of large working space, low cost and more flexibility, industrial robots have become an important carrier in intelligent manufacturing. Due to the low rigidity of robotic milling systems, cutting vibrations are inevitable and have a significant impact on surface quality and machining accuracy. To improve the machining performance of the robot, a posture optimization approach based on the dynamic response index is proposed, which combines posture-dependent dynamic characteristics with surface quality for robotic milling. First, modal tests are conducted at sampled points to estimate the posture-dependent dynamic parameters of the robotic milling system. The modal parameters at the unsampled points are further predicted using the inverse distance weighted method. By combining posture-independent modal parameters with calibrating the cutting forces, a dynamic model of a robotic milling system is established and solved with a semi-discretization method. A dynamic response index is then introduced, calculated based on the extraction of the vibration signal peaks. The optimization model is validated through milling experiments, demonstrating that optimizing redundant angles significantly enhances milling stability and quality.  
industrial robot; robotic milling; dynamic response index; chatter stability; redundant degrees of freedom +
Footnote †: journal: Applied sciences
# Review of Indoor Positioning: Radio Wave Technology
## 3 Radio Signals-Based Positioning
### UWB Technology  
UWB is an attractive technology in wireless sensor networks, which allows for very high data rates over a short distance because of its wide bandwidth. This broad bandwidth also involves a high temporal resolution, enabling a higher accuracy, and hence more accurate positioning of each target device in the network [134]. The IEEE 802.15.4a (UWB) wireless communication technologies are quickly developing and they will be in the 5G technology [29]. UWB transmission is described by its capacity to communicate short pulses with low-power spectral density in a high-frequency range, from 3.1 to 10.6 GHz. UWB wireless technology is an innovative technology for greater resolution in indoor positioning and tracking applications, such as in healthcare, medical facilities, construction sites, and sports [135; 136; 31]. Moreover, due to the nature of large bandwidth, UWB signals offer greater protection against interference. In addition, it has less impact on the human body due to the short-transmission power [71; 137].  
Localization based on UWB concentrates on the trilateration and angulation methods [29; 68; 138; 139; 140; 141] on the unknown location of a target device using three or more beacon nodes. Range-based approaches such as TOA and TDOA have good accuracy and are most suited for localization and ranging for wireless networks because of the large bandwidth of UWB signals [57]. However, RSS is hardly utilized in UWB-based positioning systems, since distance calculation is less accurate compared with using the TOA, TDOA, and AOA-based method [142]. UWB technology has many advantages, including the protection of multipath intrusion, large data rate, convenience, low power consumption, and suitable for wearable networks and body-centric applications [57; 71; 143]. The UWB technologies are mostly focused on non-line- of-sight (NLoS) modifications [134; 140]. It is able to offer centimetre and sub-metre accuracy for position measurement in an indoor localization system [31; 144]. However, an ultra-wideband-based positioning system has many challenges for high-accuracy applications in buildings, which includes sampling rate limits, device synchronization, human-body shadowing effects, antenna phase-axis variation, and multipath interference. There are many reasons for a millimetre or sub-millimetre accuracy [138; 139]. To make the higher range accuracy, the UWB-based positioning technologies require complex infrastructure and high cost [145].
# Multi platform Computer Vision System to Support Physical Fitness Assessments in Schoolchildren
###### Abstract  
Currently, the lack of physical activity can lead to health problems, with the increase in obesity in children between 8 and 18 years old being of particular interest because it is a formative stage. One of the aspects of trying to solve this problem is the need for a standardized, less subjective, and more efficient method of evaluating physical condition in these children compared to traditional approaches. Objective: Develop a multiplatform based on computer vision technology that allows the evaluation of the physical fitness of schoolchildren using smartphones. Methodology: A descriptive cross-sectional study was carried out on schoolchildren aged 8 to 18 years of both sexes. The sample was 228 schoolchildren (128 boys and 108 girls). Anthropometric measurements of weight, height, and waist circumference were evaluated. Body mass index (BMI) was calculated. Four physical tests were evaluated: flexibility (sit and reach), horizontal jump (explosive strength), biceps curl (right arm strength resistance), and sit-ups (abdominal muscle resistance). With the information collected traditionally and by filming the physical tests, a computer vision system was developed to evaluate physical fitness in schoolchildren. Results: The implemented system obtained an acceptable level of precision, reaching 94% precision in field evaluations and a percentage greater than 95% in laboratory evaluations for testing. The developed mobile application also obtained a high accuracy percentage, greater than 95% in two tests and close to 85% in the remaining two. Finally, the Systematic Software Quality Model was used to determine user satisfaction with the presented prototype. Regarding usability, a satisfaction level of 97% and a reliability level of 100% was obtained. Conclusions: Compared to traditional evaluation and computer vision, the proposal was satisfactorily validated. These results were obtained using the Expanded Systematic Software Quality Model, which reached an \"advanced\" quality level, satisfying functionality, usability, and reliability characteristics. This advance demonstrates that the integration of computer vision is feasible, highly effective in the educational context, and applicable in the evaluations of physical education classes.  
computer vision; physical fitness; schoolchildren; mobile app +
Footnote †: journal: Applied sciences
###### Abstract  
This work presents a scalable digit-parallel finite field polynomial multiplier architecture with a digit size of 32 bits for NIST-standardized binary elliptic fields. First, a dedicated digit-parallel architecture is proposed for each binary field recommended by NIST, i.e., \(163,233,283,409\) and \(571\). Then, a scalable architecture having support for all variants of binary fields of elliptic curves is proposed. For performance investigation, we have compared dedicated multiplier architectures with scalable design. After this, the dedicated and scalable architectures are compared with the most relevant state-of-the-art multipliers. All multiplier architectures are implemented in Verilog HDL using the Vivado IDE tool. The implementation results are reported on a 28 nm Virtex-7 FPGA technology. The dedicated multipliers utilize slices of 1182 (for \(m=163\)), 1451 (for \(m=233\)), 1589 (for \(m=283\)), 2093 (for \(m=409\)) and 3451 (for \(m=571\)). Moreover, our dedicated designs can operate at a maximum frequency of 500, 476, 465, 451 and 443 MHz. Similarly, for all supported binary fields, our scalable architecture (i) utilizes 3753 slices, (ii) achieves 305 MHz clock frequency, (iii) takes 0.013 \(\upmu\)s for one finite field multiplication and (iv) consumes 3.905 W power. The proposed scalable digit-parallel architecture is more area-efficient than most recent state-of-the-art multipliers. Consequently, the reported results and comparison to the state of the art reveal that the proposed architectures are well suited for cryptographic applications.  
Keywords:finite field polynomial multipliers; dedicated designs; scalable architectures; flexible implementations; binary elliptic fields; FPGA +
Footnote †: journal: Applied Sciences