scholarly journals A Probabilistic Approach to Estimating Allowed SNR Values for Automotive LiDARs in “Smart Cities” under Various External Influences

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 609
Author(s):  
Roman Meshcheryakov ◽  
Andrey Iskhakov ◽  
Mark Mamchenko ◽  
Maria Romanova ◽  
Saygid Uvaysov ◽  
...  

The paper proposes an approach to assessing the allowed signal-to-noise ratio (SNR) for light detection and ranging (LiDAR) of unmanned autonomous vehicles based on the predetermined probability of false alarms under various intentional and unintentional influencing factors. The focus of this study is on the relevant issue of the safe use of LiDAR data and measurement systems within the “smart city” infrastructure. The research team analyzed and systematized various external impacts on the LiDAR systems, as well as the state-of-the-art approaches to improving their security and resilience. It has been established that the current works on the analysis of external influences on the LiDARs and methods for their mitigation focus mainly on physical (hardware) approaches (proposing most often other types of modulation and optical signal frequencies), and less often software approaches, through the use of additional anomaly detection techniques and data integrity verification systems, as well as improving the efficiency of data filtering in the cloud point. In addition, the sources analyzed in this paper do not offer methodological support for the design of the LiDAR in the very early stages of their creation, taking into account a priori assessment of the allowed SNR threshold and probability of detecting a reflected pulse and the requirements to minimize the probability of “missing” an object when scanning with no a priori assessments of the detection probability characteristics of the LiDAR. The authors propose a synthetic approach as a mathematical tool for designing a resilient LiDAR system. The approach is based on the physics of infrared radiation, the Bayesian theory, and the Neyman–Pearson criterion. It features the use of a predetermined threshold for false alarms, the probability of interference in the analytics, and the characteristics of the LiDAR’s receivers. The result is the analytical solution to the problem of calculating the allowed SNR while stabilizing the level of “false alarms” in terms of background noise caused by a given type of interference. The work presents modelling results for the “false alarm” probability values depending on the selected optimality criterion. The efficiency of the proposed approach has been proven by the simulation results of the received optical power of the LiDAR’s signal based on the calculated SNR threshold and noise values.

Doklady BGUIR ◽  
2020 ◽  
Vol 18 (2) ◽  
pp. 89-95
Author(s):  
A. V. Khizhniak

The paper describes the application of the optimization method of fuzzy automatic classification in the problem of combining estimates of trajectory measurements in a radar system. By a radiolocation system the author mean an automated hierarchical technical complex that combines, using communication tools, a set of asynchronously functioning radiolocation tools, as well as central and intermediate points that collect, process and issue trajectory radiolocation information. It must be borne in mind that in conditions of tracking tight groups of air targets, with relatively small intervals and distances, it is not always possible to obtain trajectory information of the required quality. The main reason for this is the difficulty in determining the values of the correlation matrices of errors in estimating the parameters of the state vector of air targets. The task becomes more complicated as the number of intermediate processing points increases when it is brought to the final consumer. The main goal of the article is to increase the accuracy of estimates of trajectory measurements in a radiolocation system. The research is done by means of the mathematical tool of fuzz-set theory, namely, by optimizing fuzzy automatic classification. The article demonstrates that using fuzzy automatic classification under a priori parametrical uncertainty in the law of trajectory measurement errors, when determining weight coefficients, can improve the accuracy of estimates in these conditions up to 30 % compared with methods based on the application of the probabilistic approach. The results obtained allow us to justify the prospects of using optimization methods of fuzzy automatic classification in the tasks of processing trajectory information. In addition, the advantage of the proposed method is its low computational complexity and ease of implementation, which is especially important while maintaining a large number of airborne objects.


1995 ◽  
Vol 04 (02) ◽  
pp. 325-336 ◽  
Author(s):  
H. C. NEITZERT ◽  
C. CACCIATORE ◽  
D. CAMPI ◽  
C. RIGO

We report on the application of a self electro-optic effect device in waveguiding configuration for the generation of a wide variety of different nonlinear optical transfer functions. It makes use of the Wannier-Stark effect in an InGaAs/InP short period superlattice and operates at room temperature for TE-polarized light around 1.55 μm. In particular, optical bistability, optical signal-frequency multiplication and the operation as an optical power discriminator are demonstrated.


Author(s):  
Zoha Asgharian ◽  
Hassan Asgharian ◽  
Ahmad Akbari ◽  
Bijan Raahemi

One of the main goals of employing Next Generation Networks (NGN) is an integrated access to the multimedia services like Voice over IP (VoIP), and IPTV. The primary signaling protocol in these multimedia services is Session Initiation Protocol (SIP). This protocol, however, is vulnerable to attacks, which may impact the Quality of Service (QoS), which is an important feature in NGN. One of the most frequent attacks is Denial of Service (DoS) attack, which is generated easily, but its detection is not trivial. In this chapter, a framework is proposed to detect Denial of Service attacks and a few other forms of intrusions, and then we react accordingly. The proposed detection engine combines the specification- and anomaly-based intrusion detection techniques. The authors set up a test-bed and generate a labeled dataset. The traffic generated for the test-bed is composed of two types of SIP packets: attack and normal. They then record the detection rates and false alarms based on the labeled dataset. The experimental results demonstrate that the proposed approach can successfully detect intruders and limit their accesses. The results also confirm that the framework is scalable and robust.


2019 ◽  
Vol 40 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Kulwinder Singh ◽  
Manjeet Singh Patterh ◽  
Manjit Singh Bhamrah

Abstract In this paper, dual-order bidirectional pumping schemes of distributed fiber Raman amplifier are compared with standard first-order pumping in wavelength division multiplexed optical transmission systems. The novel comparison analysis is carried out in terms of Optical signal-to-noise ratio and Q-factor, on-off gain and noise figure by varying optical input power and fiber lengths. The results indicate that dual-order schemes present 0.02 dB higher OSNR and 5 dB higher Q-factor in comparison to first-order pumping when input optical power is varied from −4 to 5 dBm. Similarly, there is 4 dB higher on-off gain with dual order comparatively to first order when fiber length varied from 10 to 100 km. However, there is degradation in noise figure and Q-factor due to DRBS noise with dual-order pumping when fiber length from 10 to 100 km. Further, the signal power evolutions along fiber length show that there is 5 dBm improvement for 100 km fiber. The novelty of the work is that comparative analysis exhibits improvement in OSNR, on-off gain and Q-factor using dual-order bidirectional pumping.


2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Douglas Omoregie Aghimien ◽  
Clinton Aigbavboa ◽  
David J. Edwards ◽  
Abdul-Majeed Mahamadu ◽  
Paul Olomolaiye ◽  
...  

PurposeThis study presents a fuzzy synthetic evaluation of the challenges of smart city realisation in developing countries, using Nigeria as a case study. By defining and delineating the problems faced by the country, more viable directions to attaining smart city development can be achieved.Design/methodology/approachThe study adopted a post-positivist philosophical stance with a deductive approach. A structured questionnaire was used to gather data from built environment professionals involved in the delivery of Nigerian public infrastructures. Six dimensions of the challenges of smart cities were identified from literature and explored. They are governance, economic, social, technological, environmental and legal issues. Data gathered were analysed using Cronbach alpha test for reliability, Shapiro-Wilks test for normality, Kruskal-Wallis H-test for consistency and fuzzy synthetic evaluation test for the synthetic evaluation of the challenges of smart city attainment.FindingsThe findings revealed that all six assessed dimensions have a significant impact on the attainment of smart cities in Nigeria. More specifically, issues relating to environmental, technological, social and legal challenges are more prominent.Originality/valueThe fuzzy synthetic approach adopted provides a clear, practical insight on the issues that need to be addressed before the smart city development can be attained within developing countries.


Photonics ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 63 ◽  
Author(s):  
Retno Wigajatri Purnamaningsih ◽  
Nji Raden Poespawati ◽  
Tomy Abuzairi ◽  
Elhadj Dogheche

This paper details the design of a 1 × 8 optical power divider, using a gallium nitride (GaN) semiconductor on sapphire, which can be applied to underwater optical wireless communication. The design consists of nine parallel rectangular waveguides which are based on mode coupling phenomena. Analysis of the design was performed using the beam propagation method (BPM). The optimization was conducted using the 3D finite difference (FD)-BPM method with an optical signal input at the wavelength required for maritime application of λ = 0.45 µm. The signal was injected into the central waveguide. The results showed that at a propagation length of 1480 µm the optical power is divided into eight output beams with an excess loss of 0.46 dB and imbalance of 0.51 dB. The proposed design can be further developed and applied in future underwater communication technology.


2001 ◽  
Vol 8 (4/5) ◽  
pp. 281-300 ◽  
Author(s):  
E. Kazantsev

Abstract. A description of a deterministic chaotic system in terms of unstable periodic orbits (UPO) is used to develop a method of an a priori estimate of the sensitivity of statistical averages of the solution to small external influences. This method allows us to determine the forcing perturbation which maximizes the norm of the perturbation of a statistical moment of the solution on the attractor. The method was applied to the barotropic ocean model in order to determine the perturbation of the wind field which provides the greatest perturbation of the model's climate. The estimates of perturbations of the model's time mean solution and its mean variance were compared with directly calculated values. The comparison shows that some 20 UPOs is sufficient to realize this approach and to obtain a good accuracy.


2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Diego Herranz ◽  
Francisco Argüeso ◽  
Pedro Carvalho

We describe the state-of-the art status of multifrequency detection techniques for compact sources in microwave astronomy. From the simplest cases where the spectral behaviour is well known (i.e., thermal SZ clusters) to the more complex cases where there is little a priori information (i.e., polarized radio sources) we will review the main advances and the most recent results in the detection problem.


2020 ◽  
Vol 16 (5) ◽  
pp. 715-720
Author(s):  
Ali Elrashidi

Biomedical sensor that sense different molecules with a high refractive index sensitivity is proposed in this work. Plasmonic nanospiral antenna is mounted on a top surface of an optical fiber to reflect the incident optical signal back to the fiber. The reflected signal depends on the nanospiral antenna material, dimensions and the surrounding medium. Using streptavidin molecule, the nanospiral antenna have been simulated based on finite difference time domain method to optimize its dimensions. The optimum dimensions are 10 nm, 55 nm and 40 nm for inner-outer thicknesses and height respectively. The introduced biosensor can detect different molecules based on surface plasmonic resonance, which depends on the shifting of the peak wavelength according to the molecules type. The detected molecules are Streptavidin, Urease, Uricase molecules and Glucose oxidase and Cholesterol oxidase enzymes with a high sensitivity. The maximum refractive index sensitivity is obtained when sensing cholesterol oxidase molecules with 3028 nm/RIU at 3.58 μm peak wavelength. Figure of merit and quality factor are also calculated for all detected molecules. Finally, electric field and optical power, before and after binding, of the reflected signal are illustrated and discussed.


1992 ◽  
Vol 29 (4) ◽  
pp. 580-588 ◽  
Author(s):  
Farrokh Nadim ◽  
Suzanne Lacasse

A probabilistic approach to the analysis of the bearing capacity of jack-up spud can foundations is described. The procedure includes three steps: (i) a priori deterministic and probabilistic calculation of bearing capacity interaction diagram for the soil foundation under each leg of the jack up, (ii) updating of the interaction diagram from the measured vertical preloading values, and (iii) one-leg component and multileg system reliability analyses of the structure under environmental loads. The probabilistic formulation is based on the first- and second-order reliability approximations. An example calculation of a jack-up spud can structure on a layered clay profile is made to illustrate the procedure. Key words : jack up, bearing capacity, probabilistic analysis, system reliability.


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