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Within the new air traffic management concept, using the Global Navigation Satellite System (GNSS), it is assumed that distance measurement equipment (DME) will be retained. The results of research carried out by several authors have confirmed that global navigation satellite systems (GNSS) can be put out of operation in cases of interference. Therefore, it is very timely to investigate the accuracy and resistance to interference of DME systems. The presented work contains the results of research in the field of assessment of the accuracy and resistance of a DME system, which works in conditions of narrowband interference, using modeling and simulation. Based on the derived model of the DME measurement signal, its parameters, and narrowband interference, algorithms for processing the measurement signals of a DME system in conditions of narrowband interference were derived. A quasi-optimal nonlinear filtering method was used in the derivation of the measurement signal-processing algorithms. A quadratic loss function was used as an optimality criterion, which allows us to obtain the results of measuring the parameters of the DME measurement signal as a minimum of the a posteriori mean error. Within this method, Gaussian approximation and large and small parameter methods were used. Simulation of the operation of the DME system confirmed that the measurement accuracy of this system depends on the stability of the frequency of the DME support generator, and also depends on the signal-to-noise ratio and the signal-to-interference ratio of the DME receiver input. Comparing the results of the DME system receiver designed by us with the parameters listed in in published works that discuss the accuracy of this system, we can conclude that its accuracy is much better. The simulation results confirmed that the potential accuracy of the distance measurement is equal to 2.2 m. However, the mentioned algorithms require substantial simplification to be used for real-time signal processing. This will be our next research direction. [ABSTRACT FROM AUTHOR]

In interval-valued three-way decision, the reflection of decision-makers' preference under the full consideration of interval-valued characteristics is particularly important. In this paper, we propose an interval-valued three-way decision model based on the cumulative prospect theory. First, by means of the interval distance measurement method, the loss function and the gain function are constructed to reflect the differences of interval radius and expectation simultaneously. Second, combined with the reference point, the prospect value function is utilized to reflect decision-makers' different risk preferences for gains and losses. Third, the calculation method of cumulative prospect value for taking action is given through the transformation of the prospect value function and cumulative weight function. Then, the new decision rules are deduced based on the principle of maximizing the cumulative prospect value. Finally, in order to verify the effectiveness and feasibility of the algorithm, the prospect value for decision-making and threshold changes are analyzed under different risk attitudes and different radii of the interval-valued decision model. In addition, compared with the interval-valued decision rough set model, our method in this paper has better decision prospects. [ABSTRACT FROM AUTHOR]

Indoor positioning systems are used to locate and track objects in an indoor environment. Distance estimation is done using received signal strength indicator (RSSI) of radio frequency signals. However, RSSI is prone to noise and interference which can greatly affect the accuracy performance of the system. In this paper Internet of Things (IoT) technologies like low energy Bluetooth (BLE), WiFi, LoRaWAN and ZigBee are used to obtain indoor positioning. Adopting the existing trilateration and positioning algorithms, the Kalman, Fast Fourier Transform (FFT) and Particle filtering methods are employed to denoise the received RSSI signals to improve positioning accuracy. Experimental results show that choice of filtering method is of significance in improving the positioning accuracy. While FFT and Particle methods had no significant effect on the positioning accuracy, Kalman filter has proved to be the method of choice for BLE, WiFi, LoRaWAN and ZigBee. Compared with unfiltered RSSI, results showed that accuracy was improved by 2% in BLE, 3% in WiFi, 22% in LoRaWAN and 17% in ZigBee technology for Kalman filtering method. [ABSTRACT FROM AUTHOR]

The paper deals with odometers (i.e. adding machines) of general type. We give a characterization of self-conjugacies of odometers which enables us to present an elementary proof of a classification of odometers given by Buescu and Stewart in [2]. The paper might also serve as a very quick introduction to odometers. [ABSTRACT FROM AUTHOR]

Within the new air traffic management concept, using the Global Navigation Satellite System (GNSS), it is assumed that distance measurement equipment (DME) will be retained. The results of research carried out by several authors have confirmed that global navigation satellite systems (GNSS) can be put out of operation in cases of interference. Therefore, it is very timely to investigate the accuracy and resistance to interference of DME systems. The presented work contains the results of research in the field of assessment of the accuracy and resistance of a DME system, which works in conditions of narrowband interference, using modeling and simulation. Based on the derived model of the DME measurement signal, its parameters, and narrowband interference, algorithms for processing the measurement signals of a DME system in conditions of narrowband interference were derived. A quasi-optimal nonlinear filtering method was used in the derivation of the measurement signal-processing algorithms. A quadratic loss function was used as an optimality criterion, which allows us to obtain the results of measuring the parameters of the DME measurement signal as a minimum of the a posteriori mean error. Within this method, Gaussian approximation and large and small parameter methods were used. Simulation of the operation of the DME system confirmed that the measurement accuracy of this system depends on the stability of the frequency of the DME support generator, and also depends on the signal-to-noise ratio and the signal-to-interference ratio of the DME receiver input. Comparing the results of the DME system receiver designed by us with the parameters listed in in published works that discuss the accuracy of this system, we can conclude that its accuracy is much better. The simulation results confirmed that the potential accuracy of the distance measurement is equal to 2.2 m. However, the mentioned algorithms require substantial simplification to be used for real-time signal processing. This will be our next research direction.

Background: Brisk walking is recommended as a form of health-enhancing physical activity. This study determines the steps/minute rate corresponding to self-paced brisk walking (SPBW); a predicted steps/minute rate for moderate physical activity (MPA) and a comparison of the 2 findings. Methods: A convenience sample (N = 58: 34 men, 24 women, 31.7 ± 7.7yrs), wearing pedometers and a heart rate (HR) monitor, performed SPBW for 10 minutes and 5 indoor sessions, regulated by a metronome (ranging from 60-120 steps/minute). Using steps/minute and HR data of the trials, a steps/minute rate for MPA was predicted. Adjustments were subsequently made for aerobic fitness (using maximal oxygen uptake (VO2max) estimates), age, and sex as possible contributors to stepping rate differences. Results: Average steps/minute rate for SPBW was 118 ± 9 (116 ± 9; 121 ± 8 for men/women, respectively; P = .022); predicted steps/minute rate for MPA was 122 ± 37 (127 ± 36; 116 ± 39 for men/women, respectively; P < .99) and was similar to steps/minute rate of SPBW (P = .452), even after adjusting for age, sex, and aerobic fitness. Conclusion: Steps/minute rates of SPBW correlates closely with targeted HR for MPA, independent of aerobic fitness; predicted steps/minute rate for MPA relates closely to steps/minute rates of SPBW. Findings support current PA messages that use the term brisk walking as a reference for MPA. [ABSTRACT FROM AUTHOR]

The time-of-flight (ToF) principle is a method used to measure distance and construct three-dimensional (3D) images by detecting the time or the phase difference between emitted and back-reflected optical flux. The ToF principle has been employed for various applications including light ranging and detection (LiDAR), machine vision and biomedical engineering; however, bulky system size and slow switching speed have hindered the widespread application of ToF technology. To alleviate these issues, a demonstration of hetero-integration of GaN-based high electron mobility transistors (HEMTs) and GaAs-based vertical cavity surface emitting lasers (VCSELs) on a single platform via a cold-welding method was performed. The hetero-integrated ToF sensors show superior switching performance when compared to silicon-transistor-based systems, miniaturizing size and exhibiting stable ranging and high-resolution depth-imaging. This hetero-integrated system of dissimilar material-based high-performance devices suggests a new pathway towards enabling high-resolution 3D imaging and inspires broader range application of heterogeneously integrated electronics and optoelectronics. [ABSTRACT FROM AUTHOR]

The primary purpose of this study was to investigate the accuracy of the activPAL physical activity monitor in measuring step number and cadence in older adults. Two pedometers (New-Lifestyles Digi-Walker SW-200 and New-Lifestyles NL-2000) used in clinical practice to count steps were simultaneously evaluated. Observation was the criterion measure. Twenty-one participants (65-87 yr old) recruited from community-based exercise classes walked on a treadmill at 5 speeds (0.67, 0.90, 1.12, 1.33, and 1.56 m/s) and outdoors at 3 self-selected speeds (slow, normal, and fast). The absolute percentage error of the activPAL was <1% for all treadmill and outdoor conditions for measuring steps and cadence. With the exception of the slowest treadmill speed, the NL-2000 error was <2%. The SW-200 was the least accurate device, particularly at slower walking speeds. The activPAL monitor accurately recorded step number and cadence. Combined with its ability to identify primary postures, the activPAL might be a useful and versatile device for measuring activity in older adults. [ABSTRACT FROM AUTHOR]

The age-related decline in physical activity during adolescence is well documented; however, little is known about differences in physical activity among early, average, and late maturing adolescents. The purpose of this study was to examine the relationship between maturity status and physical activity among 167 adolescents who were 13-14 years old. The maturity offset was derived and biological maturity groups were created. Habitual physical activity was determined with a pedometer over a 7-day period. No significant maturity-group differences were found for physical activity. The results of this study did not demonstrate significant differences in physical activity as determined by a pedometer among early, average, and late maturing 13- to 14-year-olds. [ABSTRACT FROM AUTHOR]

The purpose of the study was to examine the accuracy of pedometer steps and activity time (Walk4Life, WL) for youth with developmental disabilities. Eighteen youth (11 girls, 7 boys) 4-14 years completed six 80-meter self-paced walking trials while wearing a pedometer at five waist locations (front right, front left, back right, back left, middle back). Trials were video taped to determine actual steps and activity time. Time exhibited a smaller percent error in comparison to steps across locations. Apart from the front left, location had minimal influence on accuracy. The WL demonstrates acceptable accuracy for steps and activity time. [ABSTRACT FROM AUTHOR]

We examined the reliability of scores from physical activity monitors in a sample of 193 individuals with multiple sclerosis (MS) who wore a pedometer and an accelerometer for a 7-day period. There were no significant differences among days for the pedometer (p = .12) or the accelerometer (p = .15) indicating that week and weekend days can be analyzed in a single intra-class correlation (ICC) analytic model. The 7 days of monitoring yielded ICC estimates of .93 for both the pedometer and accelerometer, and a minimum of 3 days yielded a reliability of .80 for both the pedometer and accelerometer. Results indicated that physical activity monitor scores are reliable measures of physical activity for individuals with MS. [ABSTRACT FROM AUTHOR]

Thirty-five youth with visual impairments (13.5 ± 2.1yrs, 13 girls and 22 boys) walked four 100-meter distances while wearing two units (right and left placement) of three brands of voice-announcement (VA) pedometers (Centrios Talking Pedometer, TALKiNG Pedometer, and Sportline Talking Calorie Pedometer 343) and a reference pedometer (NL2000). Registered pedometer steps for each trial were recorded, compared to actual steps assessed via digital video. Inter-unit agreement between right and left VA pedometer placement was low (ICC range .37 to .76). A systematic error was observed for the VA pedometers on the left placement (error range 5.6% to 12.2%), while right placement VA pedometers were at or below ± 3% from actual steps (range 2.1% to 3.3%). The reference pedometer was unaffected by placement (ICC .98, error ∼1.4%). Overall, VA pedometers demonstrated acceptable accuracy for the right placement, suggesting this position is necessary for youth with visual impairments. [ABSTRACT FROM AUTHOR]

Tracking refers to the tendency for individuals to maintain their rank in a group over time. The authors explored tracking of pedometer-determined physical activity. In October of 2000, 2003, and 2005, data of physical activity as steps per day were collected with sealed Yamax SW-200 pedometers (Tokyo, Japan) for 4 consecutive schooldays in 97 (46 boys and 51 girls) Swedish adolescents (mean age 12.7 in 2000). In general, tracking of pedometer-determined physical activity was low to moderate during adolescence. A sex difference, with boys expressing higher tracking, was seen. Moderate tracking was seen in the individuals who, according to recommendations, were insufficiently active. [ABSTRACT FROM AUTHOR]

Activity measurement using uniaxial pedometers was validated against behavioral observation using the Children's Activity Rating Scale (CARS) in 30 three- to four-year-old children in a nursery school setting. Correlations were calculated for individual children, whereas the relationship for the total group was investigated using multilevel linear regression. The mean counts for boys and girls for the Digiwalker(tm) were 66.8 (± 64.0) and 47.4 (± 61.3; p < .01) steps per 3 minutes, respectively, whereas the mean CARS scores for boys and girls were 1.8 (± 0.6) and 1.6 (± 0.6; p < .01), respectively. Within-child correlations for CARS versus Digiwalker counts ranged from 0.64 to 0.95 with a median value of 0.86; the multilevel analysis provided strong evidence of a relationship between CARS and Digiwalker (all p < .001). Data from the current study show that gender differences in physical levels exist in very young children and support the utility of the Digiwalker pedometer for assessing physical activity in this age group. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to describe the pedometer-determined physical activity levels of American youth. Methods: A secondary analysis of six existing data sets including 1839 (1046 females, 793 males; ages 6 to 18) school-aged, predominantly white subjects from the southwest US. Grade clusters for elementary (grades 1 to 3), upper elementary (grades 4 to 6), middle school (grades 7 to 9), and high school (grades 10 to 12) were created for statistical analysis. Results: Males in grades 1 to 3 and 4 to 6 accumulated significantly more steps/d (13,110 ± 2870 and 13,631 ± 3463, respectively; P < 0.001) than males in grades 7 to 9 and 10 to 12 (11,082 ± 3437 and 10,828 ± 3241). Females in grades 1 to 3 and 4 to 6 accumulated significantly more steps/d (11,120 ± 2553 and 11,125 ± 2923; P < 0.001) than females in grades 7 to 9 and 10 to 12 (10,080 ± 2990 and 9706 ± 3051). Conclusions: Results are consistent with those reported for other objective assessments of youth activity indicating that males are typically more active than females and physical activity is less prevalent among secondary school youth than those in elementary school. Pedometer-determined physical activity levels of youth, including secondary school youth, are higher than reported for adult populations. [ABSTRACT FROM AUTHOR]

The study was undertaken to evaluate (a) the reliability of pedometer data and reactivity of children to wearing a pedometer, (b) the effectiveness of a missing data replacement procedure, and (c) the validity of the Leisure Time Exercise Questionnaire (LTEQ). Six days of pedometer data were collected from 299 middle-school children, followed by administration of the LTEQ. Six days of pedometer data were found to be adequately reliable for research into habitual physical activity (Rxx = .79) and no reactivity occurred. Inclusion of weekday and weekend scores is recommended where possible. The individual-centered data-replacement procedure did not adversely affect reliability, so this data-replacement method offers great promise to physical activity researchers who wish to maintain statistical power in their studies. The LTEQ does not appear to measure physical activity similarly to pedometers (r = .05), and researchers should use the LTEQ with caution in children until further research explains this discrepancy. [ABSTRACT FROM AUTHOR]

In this study, pedometer counts were recorded for 6 consecutive days for 92 children (mean age = 9.6 years; range 6.5-12.7) and were compared with the number of minutes per day in which the participants engaged in moderate-to-vigorous physical activity (MVPA). Diaries filled out with assistance of one of the children's parents were used to determine minutes of MVPA. The average daily step count was significantly higher in boys than in girls, although the average daily MVPA engagement in minutes did not vary significantly between genders. Based on the regression equations, 60 minutes of MVPA was equivalent to 15,340 step counts in boys, 11,317 step counts in girls, and 13,130 step counts when results for both genders are combined. A moderate correlation (r = .39, p < .001) was found between pedometer step counts and reported minutes of MVPA. According to the present study findings, however, predictions and promotion of daily MVPA engagement in children based on pedometer counts per day should be made with caution. [ABSTRACT FROM AUTHOR]

Reactivity refers to a change in activity patterns that results from participants' awareness that their activity levels are being monitored. Previous research has demonstrated that children do not exhibit reactivity when mechanically sealed pedometers are used to measure activity levels. The purpose of this study was to determine whether reactivity occurred when using unsealed pedometers. Forty-five fourth-grade children wore pedometers for 8 days: 4 days sealed and 4 days unsealed. The results suggest that reactivity does not exist when using unsealed pedometers. Accidental resets proved to be a problem; therefore, the use of sealed pedometers might be necessary in order to prevent data losses. [ABSTRACT FROM AUTHOR]

Walking is a common physical activity reported by individuals with mental retardation (MR). This study examined the accuracy and feasibility of pedometers for monitoring walking in 20 adults with MR. Also, step counts and distance walked were recorded for one week. Pedometer counts were highly consistent with actual step counts during normal and fast paced walking on two ground surfaces. Intraclass correlation coefficients were above .95. A t-test revealed no gender differences in walking activity. A 2 X 2 ANOVA indicated that participants with Down Syndrome (DS) accumulated significantly fewer step counts than those without DS and participants walked more on weekdays than weekends. [ABSTRACT FROM AUTHOR]

Highlights • A RF-modulated pulsed laser generated by a FSF loop is investigated. • The RF modulation depth and pulse waveform properties are investigated. • The falling-edge RF-modulated pulse is used as a transmitter to measure distance. • A new hybrid TOF/Phase-shift method is proposed for absolute distance measurement. • This hybrid method could enhance the measurement range and precision simultaneously. Abstract We propose a hybrid time-of-flight/phase-shift (TOF/phase-shift) method using a falling-edge radio-frequency-modulated (RF-modulated) pulsed laser for absolute distance measurement. The principle of the new hybrid TOF/phase-shift technique is based on the use of an RF-modulated pulse to benefit from both the long unambiguous distance of the pulsed TOF method and the accuracy of the RF phase-shift measurement. The RF-modulated pulse is obtained using a pulsed frequency-shifted amplifying loop coupled to a single-frequency laser. The RF modulation depth and pulse waveform properties of the optical fiber loop are investigated. Then, the fully fibered RF-modulated source is applied to a laboratory distance measurement. We show experimentally that the hybrid TOF/phase-shift method is a promising technique that achieves 3 mm precision in the 1.5 km measurement range (in fiber), corresponding to a relative precision of 2 × 10−6. [ABSTRACT FROM AUTHOR]

The application of robots plays an important role in the development of intelligent production and life. At present, most robots avoid the obstacle in the process of robot operation through a single ultrasonic ranging, and it cannot guarantee the accuracy of the obstacle avoidance of robots. In this paper, an intelligent distance measurement method of robot obstacle avoidance in a cloud computing environment is designed and studied. Based on the DSP and ultrasonic global positioning system, a multi-channel ultrasonic transmitter/receiver module is adopted to design an autonomous obstacle avoidance control system based on ultrasonic waves and a new fuzzy reasoning method is proposed to realize the function of intelligent distance measurement of robot obstacle avoidance in the cloud computing environment. The simulation and field test for the intelligent distance measurement system of the obstacle avoidance is carried out by Visual C ++ visual programming software. The reliability and feasibility of the system are verified, which provides a wider space for the research and development of the robot. [ABSTRACT FROM AUTHOR]

The objective of the paper is that of constructing finite Gaussian mixture approximations to analytically intractable density kernels. The proposed method is adaptive in that terms are added one at the time and the mixture is fully re-optimized at each step using a distance measure that approximates the corresponding importance sampling variance. All functions of interest are evaluated under Gaussian product rules. Since product rules suffer from an obvious curse of dimensionality, the proposed algorithm as presented is only applicable to models whose non-linear and/or non-Gaussian subspace is of dimension up to three. Extensions to higher-dimensional applications would require the use of sparse grids, as discussed in the paper. Examples include a sequential (filtering) evaluation of the likelihood function of a stochastic volatility model where all relevant densities (filtering, predictive and likelihood) are closely approximated by mixtures. [ABSTRACT FROM AUTHOR]

Highlights • We proposed a new similarity/distance measure between intuitionistic fuzzy sets. • The given IFSs are transformed into the corresponding isosceles triangles. • The transformed isosceles triangles of IFS are placed in different axes. • This measure is defined by the intersections of the transformed isosceles triangles. • This measure is applied to pattern recognition problems to verify its rationality. Abstract Intuitionistic fuzzy set (IFS) is a representative model of fuzzy theory, and it is widely used to deal with fuzzy and uncertain problems in many practical applications. In IFS theory, the calculation of the distance and similarity between IFSs are significant techniques that are effective measurement methods for distinguishing the similarity degree between IFSs, and the two measures can be used in pattern recognition, decision-making and so on. In this paper, a novel similarity/distance measure between IFSs is proposed according to the intersections of the transformed isosceles triangles from IFSs, and the isosceles triangles are placed in a square area; furthermore, the properties of the proposed measure are also analyzed to prove whether the measure satisfies the definition of the similarity/distance measure for IFSs or not. The numerical experiments are implemented to test the validity of the proposed measure; in addition, several pattern recognition and clustering problems are also employed to further demonstrate its effectiveness. The experimental results show that the proposed measure is an accurate and superior measure that can avoid the shortcomings of most existing measures. Finally, the directions for future research of this work are also represented in the conclusion. [ABSTRACT FROM AUTHOR]

Adaptive x-ray mirrors are emerging as one of the primary solutions for meeting the performance needs of the next generation of x-ray light sources. Currently, these mirrors operate open loop with intermittent feedback from invasive sensors that measure the beam quality. This paper outlines a novel design for real-time in situ metrology of the shape of these mirrors using an array of interferometric sensors that does not interrupt the x-ray beam. We describe a proof-of-principle demonstration which shows sub-nm agreement over a range of mirror deflection magnitudes and shapes as compared to simultaneous measurements by using a large-aperture Fizeau interferometer. [ABSTRACT FROM AUTHOR]

Abstract The imaging flash lidar has been considered as a promising sensor for the future space missions such as autonomous safe landing, spacecraft rendezvous and docking due to its ability to provide a full 3D scene with a single or multiple laser pulses. The linear-mode flash lidar has been developed and demonstrated for an autonomous safe landing on the Moon in order to provide an accurate distance measurement to the landing site and its 3D image. Yet, the Geiger-mode flash lidar has also been recognized as an emerging technology for the space missions because it is highly sensitive even to a single photon and provides the very accurate timing of photon arrival. In this study, the performance of the Geiger-mode flash lidar is simulated in the approach phase and evaluated for the autonomous landing on the Moon. Furthermore, a new statistical signal processing algorithm is proposed to remove the noise counts in order to obtain the 3D image from a sequence of laser pulses in the situation of the fast moving spacecraft. The algorithm is shown to be effective for the autonomous landing due to its ability to remove noise events under the condition of low signal-to-noise ratio and improve ranging accuracy. [ABSTRACT FROM AUTHOR]

Abstract The comparability and reliability of global positioning system (GPS) devices during running protocols associated with team-sports was investigated. Fourteen moderately-trained males completed 690 m of straight-line movements, a 570 m change of direction (COD) course and a 642.5 m team-sport simulated circuit (TSSC); on two occasions. Participants wore a FieldWiz GPS device and a Catapult MinimaxX S4 10-Hz GPS device. Typical error of measurement (TE) and coefficient of variation (CV%) were calculated between GPS devices, for the variables of total distance and peak speed. Reliability comparisons were made within FieldWiz GPS devices, between sessions. Small TE were observed between FieldWiz and Catapult GPS devices for total distance and peak speed during straight-line (16.9 m [2%], 1.2 km·h−1 [4%]), COD (31.8 m [6%], 0.4 km·h−1 [2%]) and TSSC protocols (12.9 m [2%], 0.5 km·h−1 [2%]), respectively, with no significant mean bias (p > 0.05). Small TE were also observed for the FieldWiz GPS device between sessions (p > 0.05) for straight-line (9.6 m [1%], 0.2 km·h−1 [1%]), COD (12.8 m [2%], 0.2 km·h−1 [1%]) and TSSC protocols (6.9 m [1%], 0.6 km·h−1 [2%]), respectively. Data from the FieldWiz GPS device appears comparable to established devices and reliable across a range of movement patterns associated with team-sports. [ABSTRACT FROM AUTHOR]

To probe the potential value of a radar-driven field campaign to constrain simulation of isolated convection subject to a strong aerosol perturbation, convective cells observed by the operational KHGX weather radar in the vicinity of Houston, Texas, are examined individually and statistically. Cells observed in a single case study of onshore flow conditions during July 2013 are first examined and compared with cells in a regional model simulation. Observed and simulated cells are objectively identified and tracked from observed or calculated positive specific differential phase (KDP) above the melting level, which is related to the presence of supercooled liquid water. Several observed and simulated cells are subjectively selected for further examination. Below the melting level, we compare sequential cross-sections of retrieved and simulated raindrop size distribution parameters. Above the melting level, we examine time series of KDP and radar differential reflectivity (ZDR) statistics from observations and calculated from simulated supercooled rain properties, alongside simulated vertical wind and supercooled rain mixing ratio statistics. Results indicate that the operational weather radar measurements offer multiple constraints on the properties of simulated convective cells, with substantial value added from derived KDP and retrieved rain properties. The value of collocated three-dimensional lightning mapping array measurements, which are relatively rare in the continental U.S., supports the choice of Houston as a suitable location for future field studies to improve the simulation and understanding of convective updraft physics. However, rapid evolution of cells between routine volume scans motivates consideration of adaptive scan strategies or radar imaging technologies to amend operational weather radar capabilities. A three-year climatology of isolated cell tracks, prepared using a more efficient algorithm, yields additional relevant information. Isolated cells are found within the KHGX domain on roughly 40% of days year-round, with greatest concentration in the northwest quadrant, but roughly fivefold more cells occur during June through September. During this enhanced occurrence period, the cells initiate following a strong diurnal cycle that peaks in the early afternoon, typically follow a south-to-north flow, and dissipate within an hour, consistent with the case study examples. Statistics indicate that ~ 150 isolated cells initiate and dissipate within 70 km of the KHGX radar during the enhanced occurrence period annually, and roughly ten times as many within 200 km, suitable for multi-instrument Lagrangian observation strategies. In addition to ancillary meteorological and aerosol measurements, robust vertical wind speed retrievals would add substantial value to a radar-driven field campaign. [ABSTRACT FROM AUTHOR]

In this paper, we proposed an indirect method to measure the distance of an object accurately by single visual cameras using triangulation. The object can be seen as the third point of a triangle with two known sides and one known angle. Distance to object can be determined indirectly on the base of known sides and angle, rather than being measured directly. It would be very useful in case there is no line of sight to object (inaccessible) or an obstacle interrupts it. Furthermore, the results show that the measured distance using the indirect method has a lower measurement error than the one using the direct method. This method establishes a basis for the implementation of the position algorithm into the navigation subsystem of swarm robots and will be very helpful especially in robot cooperation. [ABSTRACT FROM AUTHOR]

This study is the first to adapt stereoscopic imaging to measure tree distance and diameter under forest canopies with spherical panoramas. The proposed stereoscopy method requires two spherical panoramas taken at a known distance directly on top of each other. The geometry was comprehensively laid out. Twenty-three plots were randomly established in planted forests. Sample trees were selected with a small basal area factor (BAF) for diameter at breast height and horizontal distance measurement. A larger BAF was used to subsample trees for upper stem diameters. Only fully visible trees were used in the analysis. Results showed that precision decreased with increasing distance from plot centre. Tree distance could be accurately and precisely estimated up to a distance of ~10 m from plot centre. For tree diameters, better accuracy and precision was achieved when a tree was within 5 m from plot centre or its diameter was less than 20 cm. Maintaining the required vertical displacement between panoramas was challenging in the field due to difficult terrain and heavy equipment, which are likely sources of error. With continued advancement in photography equipment, shooting spherical panorama becomes easier. Our proposed method could potentially lead to a citizen science based forest resources monitoring programme. [ABSTRACT FROM AUTHOR]

Chromatic adaptation is needed to accurately reproduce the color appearance of an image. Imaging systems have to apply a transform which converts a color of an image captured under an input illuminant to another output illuminant. This transform is called chromatic adaptation transform (CAT). Different CATs have been proposed in the literature such as von Kries, Bradford, and Sharp; both consider the adjustment of all the image spatial contents (edges, texture, and homogeneous area) in the same way. Our intuition is that CATs behave differently on the image spatial content. To verify that, we prospect to study the well-known CATs influence on the image spatial content, according to some objective criteria. Based on observations we made, new CATs are derived considering the image spatial content. To achieve that, suitable requirements for CAT are revised and rewritten in a variational formalism. Encouraging results are obtained while comparing the proposed CATs to well-known ones. [ABSTRACT FROM AUTHOR]

Gene clustering is one of the most important problems in bioinformatics. In the sequential data clustering, hidden Markov models (HMMs) have been widely used to find similarity between sequences, due to their capability of handling sequence patterns with various lengths. In this paper, a novel gene clustering scheme based on HMMs optimized by particle swarm optimization algorithm is introduced. In this approach, each gene sequence is described by a specific HMM, and then for each model, its probability to generate individual sequence is evaluated. A hierarchical clustering algorithm based on a new definition of a distance measure has been applied to find the best clusters. Experiments carried out on lung cancer-related genes dataset show that the proposed approach can be successfully utilized for gene clustering. [ABSTRACT FROM AUTHOR]

This article presents a high-precision multi-modal approach for localizing moving cameras with monocular videos, which has wide potentials in many intelligent applications, including robotics, autonomous vehicles, and so on. Existing visual odometry methods often suffer from symmetric or repetitive scene patterns, e.g., windows on buildings or parking stalls. To address this issue, we introduce a robust camera localization method that contributes in two aspects. First, we formulate feature tracking, the critical step of visual odometry, as a hierarchical min-cost network flow optimization task, and we regularize the formula with flow constraints, cross-scale consistencies, and motion heuristics. The proposed regularized formula is capable of adaptively selecting distinctive features or feature combinations, which is more effective than traditional methods that detect and group repetitive patterns in a separate step. Second, we develop a joint formula for integrating dense visual odometry and sparse GPS readings in a common reference coordinate. The fusion process is guided with high-order statistics knowledge to suppress the impacts of noises, clusters, and model drifting. We evaluate the proposed camera localization method on both public video datasets and a newly created dataset that includes scenes full of repetitive patterns. Results with comparisons show that our method can achieve comparable performance to state-of-the-art methods and is particularly effective for addressing repetitive pattern issues. [ABSTRACT FROM AUTHOR]

Abstract Evaluating similarity between moving objects' trajectories has gained much attention in many application domains. There exist similarity measures in the literature that propose evaluating similarity between trajectories in the form of time stamped values. Their main drawback is that the similarity evaluation is affected by the different sampling rates as it is defined over sequences of time stamped values. One of these measures is the Time Warp Edit distance measure that was our base of measuring similarity in our TWEDistance operator. Therefore, in this paper, a comparative study is made between four different approaches: TWEDistance operator, regression, interpolation and curve barcoding. Similarity evaluation is made over trajectories of different sampling rates. Results show that interpolation achieves the highest accuracy compared to the other approaches with an average accuracy up to 90%. Experimental evaluation was made over synthetic and real datasets. [ABSTRACT FROM AUTHOR]

Abstract: The main feature of Pythagorean fuzzy sets is that it is characterized by five parameters, namely membership degree, nonmembership degree, hesitancy degree, strength of commitment about membership, and direction of commitment. In this paper, we first investigate four existing comparison methods for ranking Pythagorean fuzzy sets and point out by examples that the method proposed by Yager, which considers the influence fully of the five parameters, is more efficient than the other ones. Later, we propose a variety of distance measures for Pythagorean fuzzy sets and Pythagorean fuzzy numbers, which take into account the five parameters of Pythagorean fuzzy sets. Based on the proposed distance measures, we present some similarity measures of Pythagorean fuzzy sets. Furthermore, a multiple criteria Pythagorean fuzzy group decision‐making approach is proposed. Finally, a numerical example is provided to illustrate the validity and applicability of the presented group decision‐making method. [ABSTRACT FROM AUTHOR]

The article presents the apps which being the compilation of sources provided by a group of secondary and tertiary geographers. Topics include the function of Distance Measure being to measure the distances on aerial photographs of current location; the function of Distance meter being to measure distance from the height of an object; and the function of Sound meter being to measure sound by decibel readings.

Graphical abstract Highlights • We proposed a neutrosophic recommender system (NRS) based on neutrosophic set. • Algebraic operations and similarity measures of NRS were studied. • A new algorithm using the similarity measures was designed for medical diagnosis. • It was validated on the benchmark datasets in terms of MSE and computational time. • The strength of all algorithms was analyzed by ANOVA statistical tool. Abstract Medical diagnosis is a procedure for the investigation of a person’s symptoms on the basis of disease. This problem has been investigated and applied to personal healthcare systems in medicine. The relevant methods have limitations regarding neutrosophication, deneutrosophication, similarity measures, correlation coefficients, distance measure, and patients’ history. In this paper, we propose a novel neutrosophic recommender system for medical diagnosis based on algebraic neutrosophic measures. Specifically, a single-criterion neutrosophic recommender system (SC-NRS) and a multi-criteria neutrosophic recommender system (MC-NRS) accompanied by algebraic operations such as union, complement and intersection are proposed. Several types of similarity measures based on the algebraic operations and their theoretic properties are investigated. A prediction formula and a new forecast algorithm using the proposed algebraic similarity measures are designed. The proposed method is experimentally validated on some benchmark medical datasets against the relevant ones namely ICSM, DSM, CARE and CFMD. The experiments demonstrate that the proposed method has better Mean Square Error (MSE) than the other algorithms. Besides, there is no large increase in computational time taken by the proposed method and other algorithms. Experiments by various cases of parameters suggest that the MSE values remain almost the same for each dataset when randomly changing the values of parameters in all the medical datasets. Lastly, the strength of all the algorithms is analyzed through ANOVA one-way test and Kruskal-Wallis test. The proposed method has better accuracy than the related algorithms. Experimental results support the advantage and superiority of the proposed method. [ABSTRACT FROM AUTHOR]

Average distances are widely used in many fields for calculating the distances between two sets of elements. This paper presents several new average distances by using the ordered weighted average, the probability and the weighted average. First, the work presents the probabilistic ordered weighted averaging weighted average distance (POWAWAD) operator. POWAWAD is a new aggregation operator that uses distance measures in a unified framework between the probability, the weighted average and the ordered weighted average (OWA) operator that considers the degree of importance that each concept has in the aggregation. The POWAWAD operator includes a wide range of particular cases including the maximum distance, the minimum distance, the normalized Hamming distance, the weighted Hamming distance and the ordered weighted average distance (OWAD). The article also presents further generalizations by using generalized and quasi-arithmetic means forming the generalized probabilistic ordered weighted averaging weighted average distance (GPOWAWAD) operator and the quasi-POWAWAD operator. The study ends analysing the applicability of this new approach in the calculation of the average fixed assets. Particularly, the work focuses on measuring the average distances between the ideal percentage of fixed assets that the companies of a specific country should have versus the real percentage of fixed assets they have. The illustrative example focuses on the Asian market. [ABSTRACT FROM AUTHOR]

In this paper we propose two algorithms, called Dir and Omni , for precisely localizing terrestrial objects, or more simply sensors, using a drone. Dir is based on the observation that, by using directional antennas, it is possible to precisely localize terrestrial sensors just applying a single trilateration. We extend this approach to the case of a regular omnidirectional antenna and formulate the Omni algorithm. Both Dir and Omni plan a static path for the drone over the deployment area, which includes a set of waypoints where distance measurements between the drone and the sensors are taken. Differently from previously proposed best-effort approaches, our algorithms prove that a guaranteed precision can be achieved by considering a set of waypoints, for each sensor, that are at a distance above a certain threshold and that surround the sensor with a certain layout. We perform extensive simulations to validate the performance of our algorithms. Results show that both approaches provide a comparable localization precision, but Dir exhibits a shorter path compared to Omni , being able to exploit the directional antennas. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess the measurement accuracy of the most commonly used tracking technologies in professional team sports (i.e., semi-automatic multiple-camera video technology (VID), radar-based local positioning system (LPS), and global positioning system (GPS)). The position, speed, acceleration and distance measures of each technology were compared against simultaneously recorded measures of a reference system (VICON motion capture system) and quantified by means of the root mean square error RMSE. Fourteen male soccer players (age: 17.4±0.4 years, height: 178.6±4.2 cm, body mass: 70.2±6.2 kg) playing for the U19 Bundesliga team FC Augsburg participated in the study. The test battery comprised a sport-specific course, shuttle runs, and small sided games on an outdoor soccer field. The validity of fundamental spatiotemporal tracking data differed significantly between all tested technologies. In particular, LPS showed higher validity for measuring an athlete’s position (23±7 cm) than both VID (56±16 cm) and GPS (96±49 cm). Considering errors of instantaneous speed measures, GPS (0.28±0.07 m⋅s-1) and LPS (0.25±0.06 m⋅s-1) achieved significantly lower error values than VID (0.41±0.08 m⋅s-1). Equivalent accuracy differences were found for instant acceleration values (GPS: 0.67±0.21 m⋅s-2, LPS: 0.68±0.14 m⋅s-2, VID: 0.91±0.19 m⋅s-2). During small-sided games, lowest deviations from reference measures have been found in the total distance category, with errors ranging from 2.2% (GPS) to 2.7% (VID) and 4.0% (LPS). All technologies had in common that the magnitude of the error increased as the speed of the tracking object increased. Especially in performance indicators that might have a high impact on practical decisions, such as distance covered with high speed, we found >40% deviations from the reference system for each of the technologies. Overall, our results revealed significant between-system differences in the validity of tracking data, implying that any comparison of results using different tracking technologies should be done with caution. [ABSTRACT FROM AUTHOR]

In some decision situations, decision makers sometimes cause this difficult problem with a few different single-valued neutrosophic values assigned by truth, indeterminacy, and falsity degrees due to decision makers’ hesitancy. Then, a single-valued neutrosophic hesitant fuzzy set (SVN-HFS) can express the hesitant information. Under a single-valued neutrosophic hesitant fuzzy environment, this paper introduces the extension method based on least common multiple cardinality for single-valued neutrosophic hesitant fuzzy elements (SVN-HFEs) and proposes the distance and similarity measures of SVN-HFSs. Then, we develop a multiple attribute decision-making (MADM) method by using the proposed similarity measure of SVN-HFSs. Finally, an illustrative example of investment alternatives is given to demonstrate the application and feasibility of the developed approach. The main advantage of the developed method is that it is more objective and more universal than the existing ones. [ABSTRACT FROM AUTHOR]

Distance and similarity measures have recently been investigated in-depth within the context of hesitant fuzzy sets. By analyzing the existing studies concerning distance measures for hesitant fuzzy sets, we find that they have some limitations. To address the flaws, this study develops some novel distance measures for hesitant fuzzy sets, including the normalized Euclidean distance measure, the Hausdorff metric distance measure, the normalized generalized distance measure, and their corresponding weighted distance measures. The proposals of this study not only hold many ideal characteristics but also do not consider the lengths of hesitant fuzzy elements as well as the arrangement of their possible values. To deal with the situations where both of the universe of discourse and the weight of element are continuous, some continuous hesitant fuzzy distance measures are also investigated. Based on the relationship between distance measure and similarity measure, some novel similarity measures for hesitant fuzzy sets can be further deduced from the proposed distance measures. Finally, two numerical examples are given to demonstrate the applicability and validity of the proposed hesitant fuzzy distance measures. [ABSTRACT FROM AUTHOR]

Abstract: This publication describes a model to generate distance measurement equipment (DME) signals as an interference source to airborne Global Satellite Navigation Systems (GNSS). Satellite navigation systems, use the lower L‐band (Galileo: E5, 1164‐1215‐MHz; GPS: L5 1164‐1189 MHz) for navigation services and are sharing the same frequency band with DME. Any GNSS receiver operating in the mentioned bands will have to deal with them as interference. Prior to this work, we only found models based on propagation estimation. No model existed which is based on real world measurements of DME signals. Thus, we carried out a flight measurement campaign at the European DME hotspot near Frankfurt (Main), Germany. From the measurement data, we have developed a measurement‐based model which is much more accurate than the existing models since it accounts for the propagation, the DME transmission, and the GNSS receiver antenna effects. We provide this model to the community to allow a more realistic forecast of the DME–GNSS interference situation. Copyright © 2018 Institute of Navigation. [ABSTRACT FROM AUTHOR]

In belief functions related fields, the distance measure is an important concept, which represents the degree of dissimilarity between bodies of evidence. Various distance measures of evidence have been proposed and widely used in diverse belief function related applications, especially in performance evaluation. Existing definitions of strict and nonstrict distance measures of evidence have their own pros and cons. In this paper, we propose two new strict distance measures of evidence (Euclidean and Chebyshev forms) between two basic belief assignments based on the Wasserstein distance between belief intervals of focal elements. Illustrative examples, simulations, applications, and related analyses are provided to show the rationality and efficiency of our proposed measures for distance of evidence. [ABSTRACT FROM AUTHOR]