Deceleration Levels Research Articles

Mobility restrictions in response to local epidemic outbreaks in rock-paper-scissors models

We study a three-species cyclic model whose organisms are vulnerable to contamination with an infectious disease which propagates person-to-person. We consider that individuals of one species perform a self-preservation strategy by reducing the mobility rate to minimise infection risk whenever an epidemic outbreak reaches the neighbourhood. Running stochastic simulations, we quantify the changes in spatial patterns induced by unevenness in the cyclic game introduced by the mobility restriction strategy of organisms of one out of the species. Our findings show that variations in disease virulence impact the benefits of dispersal limitation reaction, with the relative reduction of the organisms’ infection risk accentuating in surges of less contagious or deadlier diseases. The effectiveness of the mobility restriction tactic depends on the deceleration level and the fraction of infected neighbours which is considered too dangerous, thus triggering the defensive strategy. If each organism promptly reacts to the arrival of the first viral vectors in its surroundings with strict mobility reduction, contamination risk decreases significantly. Our conclusions may help biologists understand the impact of defensive strategies in ecosystems during an epidemic.

High-Compression Crash Simulations and Tests of PLA Cubes Fabricated Using Additive Manufacturing FDM with a Scaling Strategy

Impacts due to drops or crashes between moving vehicles necessitate the search for energy absorption elements to prevent damage to the transported goods or individuals. To ensure safety, a given level of acceptable deceleration is provided. The optimization of deformable parts to absorb impact energy is typically conducted through explicit simulations, where kinetic energy is converted into plastic deformation energy. The introduction of additive manufacturing techniques enables this optimization to be conducted with more efficient shapes, previously unachievable with conventional manufacturing methods. This paper presents an initial approach to validating explicit simulations of impacts against solid cubes of varying sizes and fabrication directions. Such cubes were fabricated using PLA, the most used material, and a desktop printer. All simulations could be conducted using a single material law description, employing solid elements with a controlled time step suitable for industrial applications. With this approach, the simulations were capable of predicting deceleration levels across a broad range of impact configurations for solid cubes.

Вплив міжнародних конфліктів на економічний розвиток

The article is an attempt to study impact of international conflicts on economic development and growth under the modern conditions of global environment. It is accentuated that the new threats and challenges are reflected in the changes going on in the principles of global development. A country is most likely to initiate a war conflict when it feels the highest degree of economic decline or when the aggressor country’s level of economic deceleration is higher than that in the country faced by a war. Autocratic countries initiate military aggressions against economically independent and politically different countries. The situation becomes even worse when it comes to an autocratic country with weak democratic institutes.

Brake-by-Wire System Redundancy Concept for the Double Point of Failure Scenario

<div>Brake-by-wire (BbW) systems are one key technology in modern vehicles. Due to their great potential in the areas of energy efficiency and automated driving, they receive more and more attention nowadays. However, increased complexity and reliance on electric and electrical components in BbW systems bring about new challenges. This applies in particular to the fault tolerance of the brake system. Since drivers cannot form a fallback layer of braking functions due to the mechanical decoupling of the brake pedal, known BbW concepts provide a redundant system layer. However, driving is significantly limited in the event of a failure in the BbW system and is only possible under certain restrictions. The reason for that is a further possible failure (double point of failure scenario), which can result in a significant loss of braking performance.</div> <div>To improve the availability level of the braking functions, a principally new redundancy concept for the double point of failure scenario is presented. This allows for a less restricted driving operation when the BbW system is subject to failures. For this purpose, a central electric motor (CEM) and modified electronic parking brake (EPB) actuators are used on the front axle of a vehicle to form a separate redundancy layer. Strategies for deceleration and wheel slip control are developed for the individual actuators as well as for their simultaneous operation. The performance of the different brake modes is evaluated in road tests. The analysis shows that especially the combined operating mode of the CEM and EPB leads to high deceleration levels and robust operation in low road friction conditions.</div>

Promotion of driver compliance with V2V information in car-following tasks via multimodal display

The success of vehicle-to-vehicle (V2V) communication in improving the driving safety and efficiency primarily depends on driver compliance with the transmitted information. In this study, driver compliance with V2V information in simulated car-following tasks was measured and analyzed under different information display settings, such as baseline without information, visual information only, and multimodal information. Car-following data were collected from 30 participants in a driving simulation environment. The results revealed that V2V information could significantly reduce the driver's response time to the lead car’s speed change, resulting in an increase in the minimum time-to-collision when the lead car slowed down. Driver compliance was significantly higher under multimodal information settings than when using visual information alone. Moreover, driver compliance was higher when facing a decelerating lead car than when facing an accelerating lead car. No significant differences in driver compliance between the deceleration levels was observed; however, differences existed among different car-following preference groups. The findings of this study can be applied to V2V car-following models to improve the simulation accuracy for connected-vehicle traffic. Additionally, multimodal information presentation can provide a reference for V2V communication design.

Energy Consumption Prediction and Analysis for Electric Vehicles: A Hybrid Approach

Range anxiety remains one of the main hurdles to the widespread adoption of electric vehicles (EVs). To mitigate this issue, accurate energy consumption prediction is required. In this study, a hybrid approach is proposed toward this objective by taking into account driving behavior, road conditions, natural environment, and additional weight. The main components of the EV were simulated using physical and equation-based models. A rich synthetic dataset illustrating different driving scenarios was then constructed. Real-world data were also collected using a city car. A machine learning model was built to relate the mechanical power to the electric power. The proposed predictive method achieved an R2 of 0.99 on test synthetic data and an R2 of 0.98 on real-world data. Furthermore, the instantaneous regenerative braking power efficiency as a function of the deceleration level was also investigated in this study.

SURVEY OF SERVICES JEND. SUDIRMAN-JALAN A.P. PETTARANI, AT MAROS CITY, SOUTH SULAWESI PROVINCE

This study aims to determine the level of service at the intersection of Jl. Jend. Sudirman-Jl. A.P. Pettarani Maros City often experiences a slowdown in the morning, afternoon, and evening. The research uses survey methods and the data processing method uses quantitative methods based on statistical data. The data required for data collection and collection includes the following data: the vehicle population is taken for 6 (six) working days. The location of this research will be carried out on the Jl. Jend.. Sudirman-Jl. A.P. Pettarani Maros City. Data analysis includes vehicle characteristics. Based on observations at the intersection of Jl. Gen. Sudirman-Jl. A.P. Pettarani Maros City often experiences a slowdown in the morning, afternoon, and evening. The volume of the vehicle is quite large. In addition, it causes traffic slowdown at intersections. In addition to the distance from other alternative roads that can be crossed, the level of deceleration on Jl. Jend.. Sudirman-Jl. A.P. Pettarani Maros City used to be often jammed so that there was a slowdown when approaching the Horse Statue Monument. Traffic regulation at this intersection is assisted by traffic lights, but there are still long queues, especially during peak hours. Meanwhile, the development of road facilities is not matched by the growth of traffic volume, so that the intersection does not serve the traffic volume.

Robust control for techno‐economic efficient energy management of fuel cell hybrid electric vehicles

The design of an efficient techno-economic autonomous fuel cell hybrid electric vehicle (FCHEV) is a crucial challenge. This paper investigates the design of a near optimal PI controller for an automated FCHEV, where autonomy is expressed as efficient and robust tracking of a given reference speed trajectory without driver's intervention. An impartial comparison is introduced to illustrate the effectiveness of the proposed metaheuristic-based optimal controllers in enhancing the system dynamic performance. The comprehensive optimization performance indicator is considered as a function of the vehicle dynamic characteristics while determining the optimal controller gains. In this paper, the proposed effective up-to-date metaheuristic techniques are the grey wolf optimization (GWO) as well as the artificial bee colony (ABC). Using MATLABTM/Simulink, numerical simulations clearly illustrate the efficiency of near-optimal gains in the optimized tuning methodologies and the fixed manual one in realizing adequate velocity tracking. The simulation results demonstrate the superiority of both ABC and GWO rather than the manual controller for driving cycles of high acceleration and deceleration levels. In absence of these latter, the manual defined gain controller is considered sufficient. Through a comprehensive sensitivity analysis, the robustness of both metaheuristic-based controllers is verified under diverse driving cycles of different operation features and nature. Despite GWO results in better dynamic characteristics, the ABC provides more economical feature with about 1.5% compared to manual system in extra urban driving cycle. However, manual-controller has the minimum fuel cost under the United States driving cycle developed by the environmental protection agency as a New York city cycle (US EPA NYCC) and urban driving cycle (ECE). Ecologically, electric vehicles have an environmentally friendly effect especially when driven with green hydrogen. Autonomous vehicles, involving velocity control systems, would raise car share and provide more comfort.

Increasing the Safety of Adaptive Cruise Control Using Physics-Guided Reinforcement Learning

This paper presents a novel approach for improving the safety of vehicles equipped with Adaptive Cruise Control (ACC) by making use of Machine Learning (ML) and physical knowledge. More exactly, we train a Soft Actor-Critic (SAC) Reinforcement Learning (RL) algorithm that makes use of physical knowledge such as the jam-avoiding distance in order to automatically adjust the ideal longitudinal distance between the ego- and leading-vehicle, resulting in a safer solution. In our use case, the experimental results indicate that the physics-guided (PG) RL approach is better at avoiding collisions at any selected deceleration level and any fleet size when compared to a pure RL approach, proving that a physics-informed ML approach is more reliable when developing safe and efficient Artificial Intelligence (AI) components in autonomous vehicles (AVs).

Crashworthy Examination of a Newly Proposed Impact Attenuator Design: Experimental Testing and Numerical Analysis

The impact attenuator is a safety vehicle system designed to absorb the kinetic energy from a collision that is converted into deformation and ensures the deceleration level acting on the human body remains low. In this paper, we propose that the impact attenuator be fabricated with used cans, which are easy to obtain. Compared to fabricating cylinders through machining and other production processes using new material, the application of used cans may reduce production costs by approximately IDR 500,000 (USD 34.50) for one attenuator structure, while the attenuator still meets the weight criterion, i.e., it has to be light to improve acceleration and fuel efficiency. As a type of metal waste product, food cans are often fabricated from aluminum and other metal alloys. These products are widely used in our lives; if they are not recycled, they can potentially pollute the environment as waste. Given these problems and considering the use of environmentally friendly materials, lightweight used cans were chosen as materials for the proposed impact attenuator design. In the initial study, the verification and validation tests of the impact attenuator shell and used cans show good agreement between the numerical and experimental impact tests. The proposed impact attenuator design under the predetermined parameters showed that used cans of aluminum 6063 series can be recommended as an alternative material in this system.

Motorcycle Autonomous Emergency Braking (MAEB) employed as enhanced braking: Estimating the potential for injury reduction using real-world crash modeling

Objective Recent field-tests on Motorcycle Autonomous Emergency Braking system (MAEB) showed that higher levels of deceleration to improve its effectiveness were feasible. However, the potential of MAEB in mitigating rider injuries is not well understood, particularly in scenarios where the efficacy of standard MAEB is limited because the rider is manually braking. The purpose of this study was first, to assess the injury mitigation potential of MAEB and second, to test MAEB as an enhanced braking system applied in circumstances where the rider is braking before a crash. Methods Data from previously investigated motorcycle injury crashes that occurred on public roads in Victoria, Australia were reconstructed using a 2D model. The intervention of MAEB was applied in the simulations to test both MAEB standard and MAEB working as enhanced braking system. The effects of MAEB in mitigating crashes were separated by crash configuration and evaluated based on the modeled reductions in impact speed and injury risk, employing injury risk functions available in the literature. Results After modeling was applied, MAEB was found to be applicable in 30 cases (91% of those in which was estimated as “possibly applicable”). The modeled Impact Speed Reduction (ISR) among the 30 cases averaged 5.0 km/h. In the cases without manual braking, the mean ISR due to standard MAEB was 7.1 km/h, whereas the relative injury risk reduction ranged from 10% for MAIS2+ to 22% for fatal injuries. In the 14 cases with manual braking, the modeled application of MAEB as enhanced braking led to an average ISR ranging from 5.3 km/h to 7.3 km/h. This resulted in an injury risk reduction ranging from 9% to 12% for MAIS2+ and from 16% to 21% for fatal injuries, depending on the different modes of MAEB. Conclusions This study modeled the potential benefits of the highest levels of intervention for MAEB field-tested to date. The findings estimate the degree to which MAEB could mitigate motorcycle crashes and reduce injury risks for motorcyclists. New strategies for MAEB intervention as enhanced braking were modeled through crash simulations, and suggest improvements in the benefits of MAEB when riders are braking before the crash. This highlighted the requirement to perform new field-based tests to assess the feasibility of MAEB deployed as enhanced braking system.

Comparative Appraisal of Three Low-Cost GPS Speed Sensors with Different Data Update Frequencies

Low-cost GPS (Global Positioning System) speed sensors have been available to quantify vehicle speed on different platforms including agricultural tractors in precision agriculture applications such as yield monitoring, variable rate fertilizer and pesticide applications. One of the advances in low-cost GPS receivers is the higher data update frequencies. However, we found no studies on the accuracy of low-cost GPS speed sensors with different update frequencies, especially under variable speed conditions. Thus, this work investigated the effect of the update frequency on the accuracy of low-cost GPS speed sensors under both constant and varying speed conditions. Three GPS speed sensors with update frequencies of 1 Hz, 5 Hz and 7 Hz (GPS1Hz, GPS5Hz and GPS7Hz) were simultaneously tested under the same conditions. A total of 144 tests were conducted on three different days and at three different times of each day with four speed levels and four repetitions. The percent errors were found to be up to 2.3%, 1.8% and 1.4% at constant speeds; up to −47%, −16% and −12% at the increasing speeds and 24%, 6% and 5% at the decreasing speeds, depending on the acceleration and deceleration levels, for GPS1Hz, GPS5Hz and GPS7Hz, respectively. The differences among the error values of the GPS speed sensors were found to be statistically significant (p < 0.05). The GPS speed sensors with higher update frequencies (5 and 7 Hz) provided higher accuracy compared to the one with lower frequency (1 Hz), particularly in the case of higher acceleration conditions. In sum, low-cost GPS speed sensors with higher update frequencies should be used for better accuracy, especially in variable speed conditions.

Impact Attenuator Optimum Design for a FSAE Racing Car by Numerical and Experimental Crash Analysis

One of the most important requirements of the Formula SAE (Society of Automotive Engineers) race car design competition is that the car structure must guarantee a high protection level in case of frontal impacts, by preventing intrusions into the driver foot zone or dangerous deceleration levels. These functions are mainly performed by the impact attenuators, which have to guarantee a high specific energy absorption capacity (SEA) and in order to preserve vehicle performances, have to be as light weighted as possible. The aim of this study is the design of an impact attenuator, to be mounted on a Formula SAE car, which main purpose is to obtain the optimal crash energy management, maximizing the absorbed energy and optimizing the geometry. The outcome of the study highlights that the absorber structure made up of honeycomb sandwich panels (primary energy absorbers), realized by means of different aluminium alloys employing an innovative design considering particular geometrical cavities within the structure, could lead to reduce the overall weight and to achieve a more progressive deformation during the impact.

Rear-end collision warning of connected automated vehicles based on a novel stochastic local multivehicle optimal velocity model

Studying the rear-end early warning methods of connected automated vehicles (CAVs) is useful for issuing early warnings and reducing traffic accidents. Establishing a corresponding driving model according to CAV characteristics is necessary when designing intelligent decision and control systems, especially for the safety speed threshold. However, since traffic systems are stochastic, there are random factors that influence car-following behavior. Therefore, this study proposes a rear-end collision warning method for CAVs based on a stochastic local multivehicle optimal speed (SLMOV) car-following model. First, the SLMOV model is proposed to characterize the car-following behavior of CAVs. Simultaneously, a stability analysis and parameter estimation method are discussed. Second, the safety distance between the CAVs changes with time because the speed of the rear vehicles satisfies the SLMOV model, which is used to calculate the safety probability of rear-end CAV collisions through an analysis of the driving process. The speed threshold is assessed by controlling the rear-end collision probability. Third, next-generation simulation (NGSIM) data are used in an empirical analysis of a rear-end collision warning method on the basis of a parameter estimation of the SLMOV model. The results present the speed thresholds of vehicles under different braking deceleration levels. Finally, the merits and demerits of fixed-speed and variable-speed adjustment time intervals are compared by considering driving safety and comfort as evaluation indexes. A reasonable CAV adjustment time interval of 0.4 s is determined. This result can be used to help develop a vehicle loading rear-end collision warning system.

A rail transit simulation system for multi-modal energy-efficient routing applications

The paper develops a continuous rail transit simulator (RailSIM) intended for multi-modal energy-efficient routing applications. RailSIM integrates sophisticated train dynamics and energy models to replicate train motion and energy consumption behavior, respectively. The simulator is calibrated using an off-line optimization procedure to match preprogramed railway schedules by optimizing three model parameters, namely; the segment target speed, the average deceleration level, and the brake force adjustment factor. The objective of the calibration procedure is to match the simulated and actual average running speed for each station-to-station pair. Upon calibration, RailSIM is applied to the Greater Los Angeles area and validated at both the instantaneous and aggregated levels. Results demonstrate that RailSIM is able to produce realistic train dynamics and energy consumption estimates producing a comfortable ride while simultaneously matching the railway schedule. RailSIM is also demonstrated to capture the impact of track gradient on energy outputs. The results also indicate that a perfect match to empirical energy estimates is achieved at an average grade of 1.8%, which is a reasonable approximation of the average track gradient of the testing area. The sensitivity of RailSIM to some of the metro rail parameters is also discussed to account for its applicability to rail transit systems in other cities. Finally, a pilot test of RailSIM implementation in the higher-level multi-modal eco-routing system is performed to demonstrate RailSIM’s feasibility of supporting energy-efficient travel.

Feasibility study of a safe sled environment for reclined frontal deceleration tests with human volunteers

Objective: The goal of the study was to assess the feasibility of a safe crash environment for volunteer tests in reclined seating positions. An iterative multimodal approach was chosen, consisting of full-body human body model (HBM) simulations, anthropomorphic test device (ATD) physical testing, and volunteer testing.Methods: To estimate a noninjurious deceleration pulse, the iterative inclination of the seat was supported through HBM simulations and physical ATD testing. One male volunteer was exposed to 5 low-speed frontal sled impacts with stepwise reclined seat angles. The volunteer was restrained with a non-pretensioned 3-point seat belt. All procedures were approved by the relevant ethics boards.Results: Volunteer sled tests in 3 different seat configurations were performed with one volunteer at noninjurious deceleration levels. Inclination of the seat and the absence of a footrest resulted in elevated axial seat reaction forces and almost pure translational motion of the human body.Conclusions: A maximum speed of 7.1 km/h and peak deceleration of 3.0 g was found to be a safe pulse for volunteer testing in frontal impacts with a rigid reclined seat. Larger soft tissue deformations were observed when reclined, possibly associated with higher shear loads within the soft tissue. Preliminary results highlight trade-offs between the degree of seat angulation, friction force, and restraint capability of a 3-point seat belt, thus causing forward translation and/or axial spinal compression of the occupant that may need to be addressed in the future.

Essential factors leading to a traumatic brain injury during low-speed fender vault pedestrian impacts

Traumatic Brain Injury (TBI) is the most common cause of serious and fatal injuries in car-to-pedestrian accidents. We used finite element models to perform a series of low-speed fender vault pedestrian impact simulations with the aim of reconstructing the primary impact phase and the final event of ground contact. We found that when compared to a sedan, a sport utility vehicle more aggressively increased the potential severity of TBI (P ˂ 0.05). In a low-speed collision, a medium level of braking deceleration (0.6 g) was found to significantly better protect the pedestrian's head when compared with low (0.3 g) and high (0.9 g) brake pulses (P ˂ 0.05), suggesting that a reasonable vehicle-to-pedestrian mechanical interaction is required to achieve a soft landing during the ground impact phase. The vehicle front-end design and proper brake deceleration control are essential contributors to a reduced TBI risk in low-speed fender vault pedestrian impact cases.

Infrared imaging of lymphatic function in the upper extremity of normal controls and hand transplant recipients via subcutaneous indocyanine green injection

Objectives:The goal of this study was to define the parameters of movement of indocyanine green in the upper extremity of normal control and hand transplant recipients. The purpose was to establish a non-invasive method of determining the level of lymphatic function in hand transplant recipients. In hand transplantation (and replantation), the deep lymphatic vessels are rarely repaired, resulting in altered lymphatic connections. In most cases, the relatively rapid inosculation of superficial lymphatic networks and drainage via the venous systems results in sufficient interstitial fluid and lymph drainage of the graft to prevent edema. However, our group and others have determined that some transplant recipients demonstrate chronic edema which is associated with lymphatic stasis. In one case, a patient with chronic edema has developed chronic rejection characterized by thinning of the skin, loss of adnexal structures, and fibrosis and contracture of the hand.Methods:Lymphatic function was evaluated by intradermal administration of near-infrared fluorescent dye, indocyanine green, and dynamic imaging with an infrared camera system (LUNA). To date, the assessment of lymphatic drainage in the upper extremity by clearance of indocyanine green dye has been studied primarily in oncology patients with abnormal lymphatic function, making assessment of normal drainage problematic. To establish normal parameters, indocyanine green lymphatic clearance functional tests were performed in a series of normal controls, and subsequently compared with indocyanine green clearance in hand transplant recipients.Results:The results demonstrate varied patterns of lymphatic drainage in the hand transplant patients that partially mimic normal hand lymphatic drainage, but also share characteristics of lymphedema patients defined in other studies. The study revealed significant deceleration of the dye drainage in the allograft of a patient with suspected chronic rejection and edema of the graft. Analysis of other hand transplant recipients revealed differing levels of dye deceleration, often localized at the level of surgical anastomosis.Conclusion:These studies suggest intradermal injection of indocyanine green and near-infrared imaging may be a useful clinical tool to assess adequacy of lymphatic function in hand transplant recipients.

Crash Performance of Oil Palm Empty Fruit Bunch (OPEFB) Fibre Reinforced Epoxy Composite Bumper Beam using Finite Element Analysis

Malaysia is categorised as one of the countries with a high number of road crashes involving deaths. This indicated the necessity of improving the safety system of a vehicle including the passive system which comprises of the bumper as one of the systems. In the frontal impact, the bumper system is the first vehicle part that receives the impact. Therefore, a crashworthy bumper that can protect the occupant is essential. In this research, the crash performance of OPEFB fibre/epoxy composite bumper beam has been investigated using finite element analysis. Low-velocity impact of 4 km/h between impact block and the bumper beam was simulated using LS-DYNA in accordance to Federal Motor Vehicle Safety Standards (FMVSS) 581 regulation. The composite was found exhibited comparable specific energy absorption with the aluminum bumper beam. Mass reduction of around 56% was observed. The peak force required for damage initiation for the composite bumper beam reduced by about 90% with impact time lengthen by around 89%. The velocity-history curves revealed a lower level of deceleration could be obtained through the utilisation of the composite bumper beam.

Risk of life-threatening arrhythmias in smoking patients

Despite the prophylactic medicine achievements through the past decade, tobacco smoking remains one of the main risk factors of appearance and progression of diseases, which are accompanied by the high population mortality. Aim : development of the new approaches of complications prediction, prophylaxis and treatment in patients with high and very high total cardiovascular risk, which are based on the heart rhythm turbulence evaluation. Materials and Methods : 603 patients were chosen for the research. All patients were divided into tree groups. The first – patients with IHD without concomitant risk factors, such as smoking, obesity, metabolic syndrome. The second – patients, who smoke for more than 2 years (people with very high cardiovascular risk by SCORE scale). The third group – patients with metabolic syndrome without IHD or hypertension (patients with high cardiovascular risk). Control group included 149 patients. Holter monitoring of the heart rhythm was performed in patients with high and very high cardiovascular risk by the SCORE scale with myocardial infarction to study the specifications of the heart rhythm turbulence. Plasma calcium and magnesium levels were measured to establish the correlation between appearance and progression of ventricular arrhythmia and increase of the heart rhythm turbulence phenomenon. Results . The prevalence of ventricular and supraventricular arrhythmia is reliably higher among the smokers than among healthy persons. The highest percentage of the ventricular extrasystoles both the early appearing extrasystoles and the group extrasystoles is observed among smokers. Among healthy people every fourth person has deviations in heart rhythm turbulence indices, and every seventeenth has significant deviations and high risk of cardiac sudden death. Smokers have reliable decrease of calcium and increase of magnesium plasma levels. People with heart rhythm turbulence, metabolic syndrome and hypertension have reliable increased in calcium plasma concentration compared with people with metabolic syndrome but without hypertension. Conclusions. 1) Smoking contributes to increase the polytopic extrasystoles prevalence. 2) Smokers have higher acceleration and deceleration levels of the heart rhythm turbulence. 3) Changes of calcium and magnesium plasma levels in smokers do not cause the ventricular extrasystole. 4) Studying of the heart rhythm turbulence is available marker of fatal arrhythmias occurrence predicting.