Method Of Distance Determination Research Articles

Multi-object distance determination by analysis of CoC variation for dynamic structured light.

A multi-object distance determination method can be achieved by 932 nm structured light with one camera as the data receiver. The structured light generated by a liquid crystal on silicon spatial light modulator (LCoS-SLM) facilitates dynamic image projection on targets. A series of moving light strip images were captured and collected for data analysis. This method lifted the limitation of single-object distance determination and the limitation of the angle requirement between the camera and the light source in the triangulation method. The average error of this method was approximately 3% in the range of 700 mm to 1900 mm away from LCoS-SLM without further optimization. It provides a potential compact design for indoor multi-object distance determination in the future.

Application of raycast method for person geolocalization and distance determination using UAV images in Real-World land search and rescue scenarios

People enjoy spending time in the wilderness for numerous reasons. However, they occasionally get lost or injured, and their survival depends on being efficiently found and rescued in the shortest possible time. A search and rescue operation (SAR) is launched after the accident is reported, and all possible resources are activated. The inclusion of drones in SAR operations has enabled the use of computer vision methods to detect persons in aerial imagery automatically. When searching by drone, preference is given to oblique photographs that cover a larger area within a single image, reducing the search time. Unlike vertical photographs, oblique photographs include a significant scale change, making it challenging to locate a person in the real world and determine their distance from the drone. In order to solve this problem, encouraged by our previous successful simulations, we explored the possibility of applying the raycast method for person geolocalization and distance determination for use in real-world scenarios. In this paper, we propose a system able to precisely geolocate persons automatically detected in offline processed images recorded during the SAR mission. After a series of experiments on terrains of different configurations and complexity, using a custom-made 3D terrain generator and raycaster, along with a deep neural network-based person detector trained on our custom dataset, we defined a method for geolocating detected person based on raycast, which allows using low-cost commercial drones with a monocular camera and no Real-Time Kinematic module while enabling laser rangefinder emulation during offline image analysis. Our person geolocating method overcomes the problems faced by previous methods and, using a single flight sequence with only 4 consecutive detections, significantly outperforms the previous best results, with reliability of 42,85% (geolocating error of 0.7 m on recording from a 30 m height). Also, a short time of only 247 s enables offline processing of data recorded during a 21-minute drone flight covering approximately an area of 10 ha, proving that the proposed method can be effectively used in actual SAR missions. We also proposed a new evaluation metric (ErrDist) for person geolocalization and provided recommendations for using the proposed system for person detection and geolocation in real-world scenarios.

Methods of Cluster Analysis for Detection of Uniform Displacement Zones of Landslides and Anti-Landslide Structures

The primary goal of landslide monitoring is the development and implementation of appropriate prediction models. Such models will allow forecasting of the anticipated landslide movements and failures. The deployment of these models is only possible by the results of geospatial monitoring. However, the measured displacements of the monitoring targets mostly have different values that may deviate a couple of times for different parts of the observed landslide. Therefore, the correct prediction model can be developed for the points with similar displacements, or in other words, for the points with the same displacement velocities. The grouping of points with similar values is known as clustering or zoning task. Having the groups of similar displacements, it is possible to work out the proper prediction model for each group of displacements and detect the probable blunders in the measurements. The paper outlines the results of geospatial monitoring for landslide and anti-landslide structures carried out for small-scale landslide and a system of retaining walls in Kyiv, Ukraine. The efficiency of cluster analysis for uniform displacement zone identification has been studied by the results of geospatial monitoring. The basic principles and ideas of cluster analysis and clustering methods have been given. The different clustering methods have been examined. Each clustering method's efficiency has been estimated by distance determination methods and similarity measures. The quantitative analysis of the considered clustering methods was checked by evaluation analysis. The most reliable results in a line of the study have demonstrated centroid clustering and furthest neighbor clustering. The determined similarity measures for those two methods were almost the same.

Carbon stars as standard candles – III. Un-binned maximum likelihood fitting and comparison with TRGB estimations

ABSTRACTIn the second paper of this series, we developed a new distance determination method using the median J magnitude of carbon-rich asymptotic giant branch stars (CS) as standard candles and the Magellanic Clouds as the fundamental calibrators. The J-band CS luminosity function was modelled using a modified Lorentzian distribution whose parameters were used to determine whether the Large or Small Magellanic cloud was the most suitable calibrator. In this third paper of the series, we expand our sample of galaxies and introduce a more robust method to determine the parameters of the Lorentzian model. The new fitting method uses an un-binned maximum likelihood estimator to determine the parameters of the Lorentzian model resulting in parameter errors that are significantly smaller compared to the second paper. We test our method in NGC 6822, IC 1613, NGC 3109, and WLM. We also estimate the distances to the same sample of galaxies via the tip of the red giant branch (TRGB) detection method. Our results from the CS measurements agree well with those obtained from the TRGB.

HARPS-N high spectral resolution observations of Cepheids

Context. The Baade-Wesselink (BW) method of distance determination of Cepheids is used to calibrate the distance scale. Various versions of this method are mainly based on interferometry and/or the surface-brightness color relation (SBCR). Aims. We quantify the impact of the SBCR, its slope, and its zero point on the projection factor. This quantity is used to convert the pulsation velocity into the radial velocity in the BW method. We also study the impact of extinction and of a potential circumstellar environment on the projection factor. Methods. We analyzed HARPS-N spectra of η Aql to derive its radial velocity curve using different methods. We then applied the inverse BW method using various SBCRs in the literature in order to derive the BW projection factor. Results. We find that the choice of the SBCR is critical: a scatter of about 8% is found in the projection factor for different SBCRs in the literature. The uncertainty on the coefficients of the SBCR affects the statistical precision of the projection factor only little (1–2%). Confirming previous studies, we find that the method with which the radial velocity curve is derived is also critical, with a potential difference on the projection factor of 9%. An increase of 0.1 in E(B − V) translates into a decrease in the projection factor of 3%. A 0.1 mag effect of a circumstellar envelope (CSE) in the visible domain is rather small on the projection factor, about 1.5%. However, we find that a 0.1 mag infrared excess in the K band due to a CSE can increase the projection factor by about 6%. Conclusions. The impact of the surface-brightness color relation on the BW projection factor is found to be critical. Efforts should be devoted in the future to improve the SBCR of Cepheids empirically, but also theoretically, taking their CSE into account as well.

Safety Distance Determination Methods for Hydrogen Refueling Stations: A Review

Safety Distance Determination Methods for Hydrogen Refueling Stations: A Review

TASER CEW distance determination for models X26P, X2, and TASER 7

TASER weapons, classified as Conducted Energy Weapons (CEWs) are used by law enforcement as electrical, non-lethal weapons. A CEW’s long distance method of deployment launches two barbed probes that embed into the target, before electricity is cycled from one probe to the other. The resulting muscle contractions help incapacitate the intended target. Currently, there is no research on the accuracy of variability of CEW probe spread in determining the distance of the shooter. Thus, in this study, a method of distance determination for TASER models X26P, X2, and TASER 7 was established to help estimate the relative locations of individuals during crime scene reconstruction. Each of four probe cartridge types were launched for six repetitions towards vertical cardboard targets from three different distances (n = 72). The probe spread on the targets was measured for each cartridge and plotted against CEW-To-Target (CTT) distance. Linear regression trendlines and standard deviations were generated for each cartridge type. Results demonstrated probe spread distances to be proportional to probe launch angles, and greater CTT distances resulted in greater standard deviation. Standard error of the estimate was calculated for all four linear regression equations and their ability to predict CTT distance when given probe spread measurements. The mean standard error values appeared acceptable for the X2 (0.460 m), TASER 7 CQ (0.273 m), and X26P (0.322 m) CEW models, while the mean error calculated for the TASER 7 Standoff model (0.846 m) was considerably greater. We expect our findings will help establish a reliable method of distance determination for CEWs, and perhaps with a larger sample size, more thoroughly examine the accuracy of the linear regression equations. CEW distance determination has the potential to provide support in contextualizing crime scene reconstruction with further research. By providing distance estimations alongside a standardized guide of error allowance, it would be possible to induce how far apart individuals were at the time a CEW was fired, within the calculated window of deviation, and in a statistical degree of confidence.

Probability of Unrecognized LiDAR Interference for TCSPC LiDAR

A standard method for distance determination is light detection and ranging (LiDAR), which relies on the emission and detection of reflected laser pulses. When LiDAR systems become common for every vehicle, many simultaneous laser signals will produce mutual LiDAR interference between LiDAR systems. In this paper, we analyze the possibility to recognize mutual interference in time-correlated single photon counting (TCSPC) LiDAR with particular focus on flash systems. We evaluate the LiDAR interference appearance by deriving the expected event distribution for ego and aggressor signal. From that, we calculate the probability of photon detection within each measured signal. This paper shows the high potential of different pulse repetition frequencies to reduce LiDAR interference. Using signal-to-noise ratio (SNR), we define the extinction distance, beyond which the aggressor signal completely extinguishes the ego signal. Applied on different background and laser event rates, we find the connection between ideal LiDAR system designs and lowest probability for unrecognized LiDAR interference. Furthermore, we show the relationship to a specific LiDAR design, which must fulfill eye safety condition and receives lower intensities with increasing target distances. Finally, we present different solutions for the recognition and reduction of LiDAR interference based on our previous results.

Influence of the stress gradient at the notch on the critical distance and life prediction in HCF and VHCF

The stress gradient associated with the notch geometry was integrated into the critical distance estimate procedure and formed the Stress Gradient Method (SGM) proposed in this study. The critical distance was discovered to be highly related to the product of the fatigue life and the stress gradient. The fatigue life of varied notched specimens was then pr edicted using SGM and three other typical critical distance determination methods. The results showed that using the SGM was beneficial for enhancing the prediction accuracy of the theory of critical distance (TCD) in the HCF regime. Furthermore, it is acceptable for applying the SGM in the VHCF regime with mean stress.

MUSE crowded field 3D spectroscopy in NGC 300

Aims.A quantitative spectral analysis of BA-type supergiants and bright giants in an inner spiral arm region of the nearby spiral galaxy NGC 300 is presented, based on observations with the Multi Unit Spectroscopic Explorer (MUSE) on the European Southern Obsevatory, Very Large Telescope. The flux-weighted gravity–luminosity relationship (FGLR), a stellar spectroscopic distance determination method for galaxies, is extended towards stars at lower luminosities.Methods.Point spread function fitting 3D spectroscopy was performed with PampelMUSE on the datacube. The 16 stars with the highest signal-to-noise ratios are classified with regard to their spectral type and luminosity class using Galactic templates. They were analysed using hybrid non-local thermodynamic equilibrium model spectra to fit the strongest observed hydrogen, helium, and metal lines in the intermediate-resolution spectra. Supplemented by photometric data, this facilitates fundamental stellar parameters and interstellar reddening which have yet to be determined.Results.Effective temperatures, surface gravities, reddeningE(B−V), bolometric magnitudes and luminosities, as well as radii and masses are presented for the sample stars. The majority of the objects follow the FGLR as established from more luminous BA-type supergiants in NGC 300. An increase in the scatter in the flux-weighted gravity–luminosity plane is observed at these lower luminosities, which is in line with predictions from population synthesis models.

Modern methods of geotechnic – effective way of providing industrial safety in mines

Results of long term researches of scientists of Kazakh National Research Technical University (KazNRTU) on the study of geomechanical processes are considered. It is shown that the problem of controlling geomechanical processes can be solved on the basis of integrated system for geomonitoring of rock massif state, providing for comprehensive accounting and analysis of all natural and man-made factors, as well as use of developed control tools by the authors. Characteristic features of ore deposits, use of various geotechnical methods in the process of their development are analyzed. Using necessity of methods of satellite geodesy, electronic tacheometers and laser scanning for open – pit mines monitoring was revealed and substantiated. Permanent ground reference which allows to ensure speed and accuracy of centering, as well as to exclude use of tripods for installation of high-precision electronic and laser devices used for earth surface geomonitoring was developed by the authors. Firstly, particular attention is drawn to underground monitoring of deformation and rock mass destruction. Mining works experience detects main cause of massif disturbance is fracturing which is probabilistic in nature. In addition, rock blasting operations during execution of interchamber pillars (ICP) are sources of additional technological rocks fracturing, that also reduces load bearing capacity and pillars and roof stability. Secondly, during mining on chamber-and-pillar development system in mined-out chambers, repeatedly increased leading rock pressure moves between support pillars or conjunction of mine workings, which threatens with sudden roof collapse ensuing serious consequences. Therefore, to monitor roof displacement during cleaning operations, distance determination method of roof displacement has been developed and ICP, which allows operational monitoring of underground workings stability and increase safety of mining operations. Method is based on the task of tool creating that allows to constantly register roof displacement in order to timely warn of impending roof collapse and take necessary measures. Thirdly, considering that ultimate goal for all geomechanical studies is to ensure industrial safety, in order to prevent further progressive pillars destruction, composition for strengthening fractured rock mass has been developed. Composition is oriented for hardening fractured rocks in open – pit mines and hardening distructed inter-chamber pillars and ceilings in underground workings. Technical result: mining waste utilization – (mill tailings), achievement of high fluidity of solution, adhesion to rocks and strength of obtained composition. Constant monitoring of state of massif fracturing and their strengthening can significantly extend service life of pillars, increase stability of worked-out space and, thereby, ensure safety and efficiency of mining operations. The work was attended by M. B. Nurpeisova, professor of Department of Mine Surveying of Kazakh National Research University named after K. I. Satpayev, Doctor of Engineering Sciences and Sh. K. Aitkazinova, PhD doctor. The study was supported by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan, Grant No. АР08857097 Integrated Monitoring of Slow Deformation on Ground Surface in the Course of Large-Scale Mineral Mining in Kazakhstan.

A Seismic Pounding Risk-based Method for Determination of Minimum Separation Distance between Nonlinear Adjacent Buildings

ABSTRACT This paper presents a seismic pounding risk-based method to determine the minimum separation distance (MSD) between nonlinear adjacent buildings. In this method, subset simulation is extended to assess seismic pounding fragility and subsequent risk. The MSD is iteratively solved corresponding to a target pounding risk. First, the proposed method is applied to both linear and nonlinear multi-degree-of-freedom systems with substantially different dynamic properties for various structural parameters. Then, the MSDs between three combinations of adjacent frame structures with unequal total heights in nonlinear finite element models are investigated using the proposed method, which are compared with different code specifications.

An adaptively reversed diffusion dual-drive evolutionary algorithm in dynamic environments for intelligence prediction

Prediction problems are difficult to be carried out in a dynamic environment, for two key questions: one is how to monitor environmental changes, the other is how to make respond timely after the environment has changed. Multi-population strategy is often adopted to address both two key problems. However, there are two stubborn questions that limit and affect the effectiveness of the strategy, i.e., (1) Search overlaps are easy to occur which lead to lose the ability of local exploit, (2) In the course of evolution, the search range of subpopulations tends to assimilate, so the subpopulation will gradually lose the ability to explore whole search space. Therefore, this paper adopts multi-population strategy, and presents a novel intelligence algorithm based on particle swarm optimization to solve the above problem, called adaptively reversed diffusion dual-drive evolutionary algorithm (ARDDEA). (1) Firstly, ARDDEA monitors the environmental changes by setting the global dynamic sentry in each subgroup. (2) Secondly, in order to avoid searching overlapping of the sub-population, a new exclusion strategy is proposed in this paper. A new distance determination method, i.e., between-swarms average Mahalanobis​ distance, is devised in the exclusion strategy to decide the inter-population distance. If the distance is too small between two sub-populations, furtherly, a Hill–valley decision function is used to determine whether they tracked the same peak or not. If so, the inferior subpopulations will be reinitialized by a reverse diffusion operation (RD) proposed in this paper. Besides, (3) a new dual-drive kinetic updating equation is proposed to enhance the search capability of the population. The new algorithm compared with several state-of-art dynamic optimization algorithms on the moving peak problem. The results show that the ARDDEA algorithm can track the optimal solution more effectively in the dynamic environment, and shows strong robustness and adaptability. It is a hope algorithm applied to prediction problems.

Carbon stars as standard candles – II. The median J magnitude as a distance indicator

ABSTRACT We introduce a new distance determination method using carbon-rich asymptotic giant branch stars (CS) as standard candles and the Large and Small Magellanic Clouds (LMC and SMC) as the fundamental calibrators. We select the samples of CS from the ((J − Ks)0, J0) colour–magnitude diagrams, as, in this combination of filters, CS are bright and easy to identify. We fit the CS J-band luminosity functions using a Lorentzian distribution modified to allow the distribution to be asymmetric. We use the parameters of the best-fitting distribution to determine if the CS luminosity function of a given galaxy resembles that of the LMC or SMC. Based on this resemblance, we use either the LMC or SMC as the calibrator and estimate the distance to the given galaxy using the median J magnitude ($\overline{J}$) of the CS samples. We apply this new method to the two Local Group galaxies NGC 6822 and IC 1613. We find that NGC 6822 has an ‘LMC-like’ CS luminosity function, while IC 1613 is more ‘SMC-like’. Using the values for the median absolute J magnitude for the LMC and SMC found in Paper I we find a distance modulus of μ0 = 23.54 ± 0.03 (stat) for NGC 6822 and μ0 = 24.34 ± 0.05 (stat) for IC 1613.

A Researcher’s View on the Proposal of Legal Regulations Regarding Major Accident Hazard Assessment in the Land Use Planning Process in Poland

This paper aims at reviewing the core Polish regulations on land‑use plan­ning (LUP) around hazardous plants and presenting a researcher’s view on the proposal of a ministerial ordinance on safety distance determination from the plants creating a major accident hazard (Seveso establishments). Currently there are no legal regulations concerning the method of safety distance deter­mination from Seveso establishments in Poland. The method of generic‑dis­tances recommended in the Polish guidelines from 2007 is not mandatory. The author stands by her opinion expressed for the first time in 2015 that Polish legal regulations on safety distance determination from Seveso establishments formulated as a ministerial ordinance are indisputably needed. If the ordinance is issued, it will contribute to a more complete implementation of the Direc­tive 2012/18/EU and will allow nationwide unification of the method of safety distance determination. The consequence‑based approach seems a reasonable option in Polish conditions. This researcher suggests an extension of the draft of the ordinance by introducing a reference tool for the mathematical mod­elling of accident consequences. It is also worth considering the introduction of legal norms for the description of areas designed in the spatial planning documents for the location of Seveso establishments.

Measurement of the distance to the central stars of Nebulae by using Expansion methods with Alladin Sky Atlas

The usual methods of distance determination in Astronomy parallax and Spectroscopic with Expansion Methods are seldom applicable to Nebulae. In this work determination of the distances to individual Nebulae are calculated and discussed. The distances of Nebulae to the Earth are calculated. The accuracy of the distance is tested by using Aladin sky Atlas, and comparing Nebulae properties were derived from these distance made with statistical distance determination. The results showed that angular Expansions may occur in a part of the nebulae that is moving at a velocity different than the observed velocity. Also the results of the comparison of our spectroscopic distances with the trigonometric distances is that the spectroscopic distances are 55% larger. Since using trigonometric parallaxes with large relative measurement errors can introduce systematic errors, we carried out a Monte Carlo simulation of the biases introduced by selection effects and measurement errors. It turns out that a difference between both distance scales of the observed size is expected for the present day data if the underlying distance scales are identical.

Toward Early-type Eclipsing Binaries as Extragalactic Milestones. I. Physical Parameters of OGLE-LMC-ECL-22270 and OGLE-LMC-ECL-06782

Abstract In this first paper of a series, we describe our project to calibrate the distance determination method based on early-type binary systems. The final objective is to measure accurate, geometrical distances to galaxies beyond the Magellanic Clouds with a precision of 2%. We start with the analysis of two early-type systems for which we have collected all the required spectroscopic and photometric data. Apart from catalog publications, these systems have not been studied yet, and this is the first time the modeling of light and radial velocity curves is performed for them. From the analysis we obtained precise physical parameters of the components, including the masses measured with a precision of 0.6%–1% and radii measured with a precision of 0.4%–3%. For one system we determined the color and estimated the distance using the bolometric flux scaling method (DM = 18.47 ± 0.15 mag), which agrees well with our accurate determination of the distance to the Large Magellanic Cloud from late-type giants. For the same system we determined the surface brightness of individual stars using our model, and checked that it is consistent with a recent surface-brightness–color relation. We compared our results with evolution theory models of massive stars and found they agree in general; however, models with higher overshooting values give more consistent results. The age of the system was estimated to range from 11.7 to 13.8 Myr, depending on the model.

Modern Geometric Methods of Distance Determination

Building a 3D picture of the Universe at any distance is one of the major challenges in astronomy, from the nearby Solar System to distant Quasars and galaxies. This goal has forced astronomers to develop techniques to estimate or to measure the distance of point sources on the sky. While most distance estimates used since the beginning of the 20th century are based on our understanding of the physics of objects of the Universe: stars, galaxies, QSOs, the direct measures of distances are based on the geometric methods as developed in ancient Greece: the parallax, which has been applied to stars for the first time in the mid-19th century. In this review, different techniques of geometrical astrometry applied to various stellar and cosmological (Megamaser) objects are presented. They consist in parallax measurements from ground based equipment or from space missions, but also in the study of binary stars or, as we shall see, of binary systems in distant extragalactic sources using radio telescopes. The Gaia mission will be presented in the context of stellar physics and galactic structure, because this key space mission in astronomy will bring a breakthrough in our understanding of stars, galaxies and the Universe in their nature and evolution with time. Measuring the distance to a star is the starting point for an unbiased description of its physics and the estimate of its fundamental parameters like its age. Applying these studies to candles such as the Cepheids will impact our large distance studies and calibration of other candles. The text is constructed as follows: introducing the parallax concept and measurement, we shall present briefly the Gaia satellite which will be the future base catalogue of stellar astronomy in the near future. Cepheids will be discussed just after to demonstrate the state of the art in distance measurements in the Universe with these variable stars, with the objective of 1% of error in distances that could be applied to our closest galaxy the LMC, and better constrain the distances of large sub-structures around the Milky Way. Then exciting objects like X-Ray binaries will be presented in two parts corresponding to “low” or “high” mass stars with compact objects observed with X-ray satellites. We shall demonstrate the capability of these objects to have their distances measured with high accuracy with not only helps in the study of these objects but could also help to measure the distance of the structure they belong. For cosmological objects and large distances of megaparsecs, we shall present what has been developed for more than 20 years in the geometric distance measurements of MegaMasers, the ultimate goal being the estimation of the $H_{0}$ parameter.

Distance determination based on the delay time-intensity profile analysis in range-gated imaging.

A method for distance determination with the help of range-gated viewing systems is proposed for an arbitrary shape of the illumination pulse. The method is based on finding the maximum of the reflected pulse energy as a function of the delay time. At the equal pulse and gate durations, there is a strict maximum, which turns into a plateau when the pulse is shorter than the gate duration. The delay times corresponding to the strict maximum or the far boundary of the plateau are directly related to the distance to an object. These results are confirmed by the numerical study of the dependence of the detected energy on the delay time for the different pulse shapes. Experimental verification of the proposed method showed accuracy 1-2m in a measuring range of 15-120m. The obtained results can be useful in the development of 3D vision systems.

1H-Detected REDOR with Fast Magic-Angle Spinning of a Deuterated Protein.

Rotational echo double resonance (REDOR) is a highly successful method for heteronuclear distance determination in biological solid-state NMR, and 1H detection methods have emerged in recent years as a powerful approach to improving sensitivity and resolution for small sample quantities by utilizing fast magic-angle spinning (>30 kHz) and deuteration strategies. In theory, involving 1H as one of the spins for measuring REDOR effects can greatly increase the distance measurement range, but few experiments of this type have been reported. Here we introduce a pulse sequence that combines frequency-selective REDOR (FSR) with 1H detection. We demonstrate this method with applications to samples of uniformly 13C,15N,2H-labeled alanine and uniformly 13C,2H,15N-labeled GB1 protein, back-exchanged with 30% H2O and 70% D2O, employing a variety of frequency-selective 13C pulses to highlight unique spectral features. The resulting, robust REDOR effects provide (1) tools for resonance assignment, (2) restraints of secondary structure, (3) probes of tertiary structure, and (4) approaches to determine the preferred orientation of aromatic rings in the protein core.