Browse Topic: Statistical analysis

Items (2,257)
Thoracic injuries, most frequently rib fractures, commonly occur in motor vehicle crashes. With an increased reliance on human body models (HBMs) for injury prediction in various crash scenarios, all thoracic tissues and structures require more comprehensive evaluation for improvement of HBMs. The objective of this study was to quantify the contribution of costal cartilage to whole rib bending properties in physical experiments. Fifteen bilateral pairs of 5th human ribs were included in this study. One rib within each pair was tested without costal cartilage while the other rib was tested with costal cartilage. All ribs were subjected to simplified A-P loading at 2 m/s until failure to simulate a frontal thoracic impact. Results indicated a statistically significant difference in force, structural stiffness, and yield strain between ribs with and without costal cartilage. On average, ribs with costal cartilage experienced a lower force but greater displacement with a longer time to
Schaffer, RoseKang, Yun-SeokMarcallini, AngeloPipkorn, BengtBolte, John HAgnew, Amanda M
In the automotive industry, a good vehicle is one that not only provides comfort and adequate on-road performance but also ensures safety for its users. Therefore, various standards have been created to qualify and ensure that cars meet minimum requirements. Assays include frontal and side impact tests. However, physical tests end up being costly if performed frequently, and thus, increasing the correlation between these and computational simulations has been explored in recent years. Within the computational scope, given the nonlinear nature of the functions involved in such studies, the use of metaheuristics (MH) with constraint handling techniques (CHT) has been employed to obtain better results for such scenarios. In this work, three MH algorithms are used: Archimedean Optimization (AOA), Sine-Cosine Algorithm (SCA), and Dung Beetle Optimization (DBO). They are coupled with CHTs of the penalty methods (PM) type in their most basic character, such as Static Penalty Method (SPM
Souza Silva, PauloDezan, Daniel JonasFerreira, Wallace Gusmão
In recent years, the automotive industry has been undergoing constant evolution, and to keep up with market trends, it’s necessary to seek better performance in the shortest time possible. Therefore, CAE (Computer Aided Engineering) becomes one of the most efficient tools for this purpose, as it can predict failures and/or improvements virtually before the start of tooling manufacturing. Thus, optimization, a process in which the best value of a parameter is obtained, becomes essential in the CAE field. In this work, Design of Experiments (DOE) will be applied, a methodology that, using applied statistics, plans, conducts, analyzes, and interprets controlled tests, evaluating predefined parameters from different areas. A light vehicle skid plate will be the case study, impacting disciplines such as durability, NVH (Noise, Vibration and Harshness), and aerodynamics, in virtual analyses such as stiffness, vibration modes, and water fording. Using the resources provided by Renault, this
dos Santos Magalhães, Daniella FernandaMoura, Vitor LoicBraga Junior, Francisco EstevanatoAndrade Barbosa, Samuel França MouraTheulen Mueller, André Marcelo
During the early phase of vehicle development, one of the key design attributes to consider is the trunk. Trunk is the pillar that is responsible for user’s accommodate their baggage and make into customer needs in engineer metrics. Therefore, it is one of the key requirements to be considered during the vehicle design. Certain internal vehicle trunk characteristics such as the trunk height and length are engineer metrics that influence the occupants’ perception for trunk. One specific characteristic influencing satisfaction is the rear opening width lower for notch back segment, which is the subject of this paper. The objective of this project is to analyze the relationship between the rear opening width lower with the occupant’s satisfaction under real world driving conditions, based on research, statistical data analysis and dynamic clinics
Santos, Alex CardosoSilva, GustavoGenaro, PieroTerra, RafaelPádua, AntônioBenevente, RodrigoLourenço, Sergio
Wire Electrical Discharge Machining (WEDM) is a widely used manufacturing method that is employed to shape complex geometries in conductive materials such as cupronickel, which is highly regarded for its resistance to corrosion and ability to conduct heat. The aspiration of this investigation is to improve the effectiveness and accuracy of Wire Electrical Discharge Machining (WEDM) for cupronickel material by utilizing the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) optimization method. The study analyzes the impact of WEDM parameters, specifically pulse-on time, pulse-off time, and discharge current, on important machining outcomes such as surface roughness, material removal rate. Experimental trials are performed to collect data on these parameters and their corresponding machining characteristics. The TOPSIS optimization method is utilized to determine the most favourable parameter settings by evaluating each parameter combination against the ideal and
Pasupuleti, ThejasreeNatarajan, ManikandanKiruthika, JothiC, NavyaSilambarasan, R
Wire Electrical Discharge Machining (WEDM) is an essential manufacturing process used to shape complex geometries in conductive materials such as cupronickel, which is valued for its corrosion resistance and electrical conductivity. The aim of this explorative study is to enhance the efficiency and precision of machining by creating a specialized predictive model using an Adaptive Neuro-Fuzzy Inference System (ANFIS) for cupronickel material. The study examines the intricate correlation between process variables of the WEDM (Wire Electrical Discharge Machining) technique, such as pulse-on time (Ton), pulse-off time (Toff), and discharge current, and crucial machining responses, including surface roughness, material removal rate. Data is collected through systematic experimentation in order to train and validate the ANFIS predictive model. The ANFIS model utilizes the collective learning capabilities of neural networks and fuzzy logic systems to precisely forecast machining responses by
Pasupuleti, ThejasreeNatarajan, ManikandanKiruthika, JothiKatta, Lakshmi NarasimhamuSilambarasan, R.
Looking at the current scenario in transportation industry, in majority of the conventional powertrains, internal combustion (IC) engines fueled by diesel serve as the powerhouse. In all locomotives driven by IC engine, it is essential to monitor critical engine parameters to ensure good engine health and performance. Exhaust temperature of engine is a very critical parameter which gives the information about in-cylinder combustion. In traditional diesel engine layouts, exhaust temperature measurement relies on physical temperature sensor. The proposed methodology is focused on applying the data driven models for providing an estimated value of the exhaust temperature. Based on the estimated value of exhaust temperature, this technique can be used to monitor the IC engine. This methodology uses an advanced Artificial Intelligence technique for providing an accurate estimate of exhaust gas temperature. Real world vehicle data was used for training, validating, and testing the data
Jagtap, Virendra ShashikantGanguly, GouravMitra, Partha
Additive Manufacturing (AM), specifically Fusion Deposition Modeling (FDM), has transformed the manufacturing industry by allowing the creation of complex structures using a wide range of materials. The objective of this study is to enhance the FDM process for Thermoplastic Polyurethane (TPU) material by utilizing the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) optimization method. The study examines the influence of FDM parameters, such as layer height, nozzle temperature, and infill density, on important characteristics of the printing process, such as tensile strength, flexibility, and surface finish. The collection of experimental data is achieved by conducting systematic FDM printing trials that cover a variety of parameter combinations. The TOPSIS optimization method is utilized to determine the optimal parameter settings by evaluating each parameter combination against the ideal and anti-ideal solutions. This method determines the optimal parameter
Pasupuleti, ThejasreeNatarajan, ManikandanKiruthika, JothiRamesh Naik, MudeSilambarasan, R
ABSTRACT Army vehicles are complex due to various on-board mission critical communication devices. The Army cannot afford unreliable software to interact between the devices. The Army vehicle software’s reliability is influenced by multiple factors during or prior to its development. Using complex statistical and mathematical models, software’s reliability can be predicted, but it is dependent on the accuracy and context of the historical software failure data. The cost of developing such complex models does not yield a good return on investment. The data collection process to use these models is very difficult and time consuming. In this paper, we propose reliability metrics based on the current software development and design process factors. We also propose a fuzzy logic based software reliability prediction algorithm using the proposed reliability metrics
Dattathreya, Macam S.Singh, Harpreet
ABSTRACT Predictive analysis of vehicle electrical systems is achievable by combining condition based maintenance (CBM) techniques and testing for statistical significance (TSS). When paired together, these two fundamentally sound sciences quantify the state of health (SOH) for batteries, alternators, starters, and electrical systems. The use of a communication protocol such as SAE J1939 allows for scheduling maintenance based on condition and not a traditional time schedule
Rini, GuyZachos, Mark
ABSTRACT Test course characterization has long relied on single-line profile measurements which provide elevation as a function of distance. These profiles are analyzed to provide various statistics and metrics. While these metrics can be useful, single-line profiles will always lead to a limited characterization. A vehicle has multiple concurrent inputs from the ground, inducing not just vertical excitations but also pitching, rolling, and twisting displacements (amongst others). Improvements in profiling equipment have enabled the ability to sample and characterize the entire surface. This paper identifies two characterization methods which take advantage of a full surface scan. The first uses orthogonal transverse modes which could either be extracted with Singular Value Decomposition (SVD) or be predefined polynomials. The second extracts a concurrent profile under each wheel for a given vehicle axle spacing and track width. Orthogonal basis vectors are then projected onto the
Liswell, Brian
ABSTRACT In the field of ground robotics, the problems of global path planning and local obstacle avoidance are often treated separately but both are assessed in terms of a cost related to navigating through a given environment. Traversal cost is typically defined in terms of the required fuel [1], required travel time [2], and imparted mechanical wear [3] to guide route selection. Prior work [4] has shown that obstacle field complexity and navigation cost can be abstracted into quantitative dimensionless parameters. But determining the cost parameters and their relationship to field complexity requires running repeated path planning simulations [4]. This work presents a method for estimating navigation cost solely from geometric obstacle field complexity measures, namely the statistical properties of an obstacle’s shape and the density of obstacles within an environment, eliminating the requirement to run a path planner in a simulation environment. Citation: S. J. Harnett, S. Brennan
Harnett, Stephen J.Brennan, SeanReichard, KarlPentzer, JesseTau, SethGorsich, David
ABSTRACT This paper reviews research that has been conducted to develop inductively assisted localized hot forming bending technologies, and to use standardized welding tests to assess the practicality and potential benefits of adopting stainless based consumables to weld both existing and evolving armor alloys. For the titanium alloy Ti6Al4V it was determined that warming the plate to circa 600°F would improve the materials ductility (as measured by reduction of area) from ~18 to 40% without exposing the material to a temperature at which atmospheric contamination would be significantly deleterious. For the commercial alloy BB and class 1 armor alloy it was found that there was little effect on the charpy impact toughness and the proof strength as a result of processing at 900 °F with either air cool or water quench and there was an added benefit of lower residual stresses in the finished bends compared to cold formed bends. Heating “alloy BB” to 1600 °F followed by water quench
Lawmon, JohnAlexandrov, BoianDuffey., MatthewNgan., Tiffany
ABSTRACT Ballistic validation testing typically involves firing multiple shots at a nominal velocity and ensuring the target stops every round with only partial penetrations, no completes. This testing is specified as a consequence of the binary nature of the test, and the need to meet a particular probability of penetration at a specified velocity with a certain confidence level. This legacy process has significant shortcomings owing to both the test procedures involved as well as the nature of the statistical interpretation of the results. This paper describes an alternative test and analysis procedure that produces the required level of performance and confidence information at a specified velocity, as well as the confidence over a wide range of other velocities and performance levels. In addition, this procedure eliminates many of the shortcomings associated with the legacy “no penetration” test protocol, and requires no more shots at the target. Citation: J. Eridon, S. Mishler
Eridon, JamesMishler, Scott
ABSTRACT This paper addresses some aspects of an on-going multiyear research project of GP Technologies for US Army TARDEC. The focus of the research project has been the enhancement of the overall vehicle reliability prediction process. This paper describes briefly few selected aspects of the new integrated reliability prediction approach. The integrated approach uses both computational mechanics predictions and experimental test databases for assessing vehicle system reliability. The integrated reliability prediction approach incorporates the following computational steps: i) simulation of stochastic operational environment, ii) vehicle multi-body dynamics analysis, iii) stress prediction in subsystems and components, iv) stochastic progressive damage analysis, and v) component life prediction, including the effects of maintenance and, finally, iv) reliability prediction at component and system level. To solve efficiently and accurately the challenges coming from large-size
Ghiocel, Dan M.Negrut, DanLamb, DavidGorsich, David
ABSTRACT In this context, a damage model is a mathematical algorithm that is used to predict if and when in a given loading history a structure will fail by ductile fracture. Increments in a damage parameter are related to strain increments and state of stress. The damage model would operate as part of a numerical simulation, or separately on an output file. A scale effect in ductile fracture is widely recognized from test data, where a large structure tends to fail at lower strain than a smaller structure that is geometrically similar and of the same material. Most damage models are not scale sensitive, and when they are calibrated to data from small laboratory specimens, they will tend to over-predict the performance (i.e., energy absorbing capability) of a larger structure. Another factor is scatter in test results even when specimens are made with care to be as identical as possible. Both of these factors are addressed in the proposed statistics-based damage model. Scale effects
Gurson, Arthur L.
ABSTRACT This research paper addresses the ground vehicle reliability prediction process based on a new integrated reliability prediction framework. The paper is an extension of the paper presented last year at the GVSETS symposium. The integrated stochastic framework combines the computational physics-based predictions with experimental testing information for assessing vehicle reliability. The integrated reliability prediction approach incorporates the following computational steps: i) simulation of stochastic operational environment, ii) vehicle multi-body dynamics analysis, iii) stress prediction in subsystems and components, iv) stochastic progressive damage analysis, and v) component life prediction, including the effects of maintenance and, finally, iv) reliability prediction at component and system level. To solve efficiently and accurately the challenges coming from large-size computational mechanics models and high-dimensional stochastic spaces, a HPC simulation-based
Ghiocel, Dan M.Negrut, DanLamb, DavidGorsich, David
ABSTRACT This paper presents the results of a series of controlled tests conducted with large explosive charges in which a number of threat parameters were systematically varied. After each test, careful measurements were made of the crater dimensions. A statistical analysis was conducted in order to relate the measured crater dimensions to the threat characteristics. The test plan examined the effects of charge size, soil type, shape of the charge, and burial depth. The results of the analysis showed that all of the threat parameters had a significant effect on the most commonly measured dimension, the crater lip diameter. As a consequence, any model that attempts to estimate charge size based solely on crater size measurements will necessarily have large predictive errors, on the order of a factor of two or more
Zeleznik, TomMiiller, MattEridon, JamesWest, Jonathan
ABSTRACT The Controller Area Network (CAN) protocol is still a de-facto standard for in-vehicle communication between Electronic Control Units (ECUs). The CAN protocol lacks basic security features such as absence of sender node information, absence of authentications mechanism and the plug and play nature of the network. The payload in a CAN data packet is very small i.e. 8 bytes, therefore, implementation of cryptographic solutions for data integrity verification is not feasible. Various methods have been proposed for ECU identification, one of the methods is clock intrusion detection system (CIDS) [14]. The proposed method is based on authenticating the message sender by estimating the unique characteristics of the clock crystal. In an asynchronous network, the clocking information in a transmitted payload is entirely dependent upon the crystal which invokes the clock. These unique characteristics exists because of the asymmetry in the microstructure of the material. The challenge
Tayyab, MuhammadHafeez, AzeemMalik, Hafiz
ABSTRACT Engine performance is traditionally measured in a dynamometer where engine speed, torque, and fuel consumption measurements can be made very accurately and environmental conditions are well controlled. Durability testing is also carried out in a dynamometer to assess reduction in engine output due to normal aging. However, the symptoms associated with incipient failures are not often studied since it requires either stressing engine components above their recommended limit or exchanging parts of known deviation with normal ones. This work describes a methodology for seeding faults in an engine by electronic means so that they can be reversibly turned on and off in a controlled fashion. The focus is on seeding faults that produce changes in engine output so that comparison between precise measurements done with laboratory instruments may be compared with estimates derived from on-board measurements. Thus, we have relied on a rather broad spectrum of measurement capabilities
Zanini, MargheritaMarko, K.James, J.Beck, Christopher S.Tom, K.Stempnik, J.
ABSTRACT The recent U.S. Army TARDEC’s 30-Year Strategy calls for enhancing their skill set in the “ilities,” especially reliability, since this factor directly impacts more than 58% of life cycle costs, according to a DoD study. To support this initiative, this paper presents technology transfer of Iowa developed Reliability-Based Design Optimization (I-RBDO) software by integrating theories and numerical methods that have been developed over a number of years in collaboration with the Automotive Research Center (ARC), which is funded by the U.S. Army TARDEC. Both the sensitivity-based and sampling-based methods for reliability analysis and design optimization methods are integrated in I-RBDO for broader multidisciplinary applications. I-RBDO has very comprehensive capabilities that include modeling of input distributions for both independent and correlated variables; a variable screening method for high dimensional RBDO problems; statistical analysis; reliability analysis; RBDO; and
Choi, K.K.Gaul, Nicholas J.Song, HyeongjinCho, HyunkyooLamb, DavidGorsich, David
ABSTRACT This paper discusses the development of a methodology to generate drive cycles having a finite duration, but which are statistically representative of a larger set of usage data collected from fleet vehicles operating in the field. Given field-generated time vs. velocity data, acceleration at each data point is calculated, and each velocity and acceleration pair is binned using some calibrated level of fidelity. As a result, a velocity-acceleration matrix representing each vehicle operating point, as well as cumulative probability distribution functions for acceleration change and take-off acceleration are generated. These cumulative distribution functions are utilized to pick random velocity-acceleration pairs from the corresponding matrix, and the concatenation of each consecutive chosen velocity-acceleration pair constitutes the final drive cycle. Three drive cycles representing the high-, medium- and low-speed operation of the vehicle are generated from the field data, and
Dagci, Oguz H.Cook, AndrewShaw, Phillip
ABSTRACT Implementing Prognostic and Predictive Maintenance (PPMx) for the U.S. Army’s ground vehicle fleet requires the design and integration of on-platform predictive analytics. To support the design process, U.S. Army DEVCOM Ground Vehicle Systems Center (GVSC) and Applied Research Laboratory (ARL) Penn State researchers are developing a systematic approach that uses reliability modeling in a guiding role. The key steps of the process are building the initial reliability model from available data (e.g., system diagrams and physical layouts), augmenting with information on observed states and failure modes via subject matter experts, and then conducting trades on additional sensors and algorithms to determine a suitable predictive analytics capability. In this paper we provide an example of this process as applied to an Army ground vehicle, first focusing on a simplified sub-problem to demonstrate the technique, then providing statistics on the large scale process. Citation: M
Majcher, MonicaBennett, Lorri A.Banks, JeffreyLukens, MatthewNulton, EricYukish, Michael A.Merenich, John J.
ABSTRACT In this paper, we discuss a neuroimaging experiment that employed a mission-based scenario (MBS) design, a new approach for designing experiments in simulated environments for human subjects [1]. This approach aims to enhance the realism of the Soldier-task-environment interaction by eliminating many of the tightly-scripted elements of a typical laboratory experiment; however, the absence of these elements introduces several challenges for both the experimental design and statistical analysis of the experimental data. Here, we describe an MBS experiment using a simulated, closed-hatch crewstation environment. For each experimental session, two Soldiers participated as a Commander-Driver team to perform six simulated low-threat security patrol missions. We discuss challenges faced while designing and implementing the experiment before addressing analysis approaches appropriate for this type of experimentation. We conclude by highlighting three example transition pathways from
Vettel, Jean M.Lance, Brent J.Manteuffel, ChrisJaswa, MatthewCannon, MarcelJohnson, TonyPaul, VictorOie, Kelvin S.
Extreme out-of-position pre-crash postures may need high-force pre-pretensioner (PPT) for effective repositioning (Mishra et al., 2023). To avoid applying a high force on the chest, we hypothesized that in case of these extreme postures the PPT may be activated in the absence of a pre-crash motion as a cautionary measure. Therefore, the aims of this study were: (1) to understand the effect of the PPT in repositioning a forward-leaning occupant in static conditions and (2) to characterize occupants’ kinematic variability during repositioning. Sixteen healthy volunteers (8 males, 8 females, 23.8 ± 4.2 years old) were seated with a 40° forward posture on a vehicle seat and restrained with a 3-point seat belt equipped with a PPT. Two PPT seatbelt conditions were examined: low PPT (100 N) and high PPT (300 N). Head and trunk rearward displacements relative to the initial forward-leaning position at 350 ms from PPT onset were collected with a 3D motion-capture system and compared between
Witmer, MaitlandGriffith, MadelineGraci, Valentina
The American Petroleum Institute’s (API) Single Technology Matrix (STM) is a data-based, Virtual Testing process and protocol (utilizes test data, characteristics and features of base stocks and blends coupled with statistical methods and analysis) used to predict the performance capability of a specific engine oil additive technology in a single specified base oil, in a given engine test. The concept was first introduced in 2002, codified and implemented by API in 2007, and updated in 2022. The previously published advantages of STM in the proof-of-performance of engine oils, remain relevant. These advantages include a data space focused on interpolation, documented statistical analysis protocol, limitation to a specific formulation, flexibility in understanding complicated, interactive, or non-linear technology and base oil relationships, and timeliness. There have been numerous changes to, and in, the engine oil industry since the introduction of STM in 2007. These include advances
Zielinski, ChristineScinto, PhilipChen, MinGibbons, GreerBaker, Charles
The Reactivity Control Compression Ignition (RCCI) engine, with its dual fuel system and coordinated injection strategy, offers superior emission control and fuel efficiency compared to conventional diesel engines. However, cyclic variations leading to engine combustion instability poses a significant challenge to their development and commercialization. In this study, statistical (COV and Histogram) and nonlinear dynamic (Recurrence Plot and its Quantification) analysis techniques are applied on the time-series data obtained from a single-cylinder diesel engine modified to operate in CNG-Diesel RCCI mode. The engine, while advancing the main injection timing (SOI-2), is tested under various operating conditions, including different engine loads, direct injection mass ratios (DIMR) and port fuel injection (PFI) masses, to help identify the configurations with better temporal correlations and deterministic traits. Such configurations hold potential for control strategy implementation
Prashar, RajatKumar, Kamal S.Yadav, Ratnesh KumarMaurya, Rakesh Kumar
The healthcare industry is evolving and facing two major challenges. First, the rise of chronic diseases. By 2050, chronic diseases such as cardiovascular diseases, cancer, diabetes, and respiratory illnesses could account for 86 percent of the 90 million deaths each year, according to the World Health Organization (WHO) in its 2023 World Health Statistics report. This increase is due to factors such as an aging population, lifestyle changes, and risk factors like high blood pressure, high blood sugar, and air pollution. Consequently, this creates a second challenge: added strain on healthcare resources. To address this, WHO recommends tackling the root causes of chronic diseases, promoting healthier behaviors, and ensuring universal access to healthcare resources
This document defines the steps and documentation required to perform a digital fiber optic link loss budget. This document does not specify how to design a digital fiber optic link. This document does not specify the parameters and data to use in a digital fiber optic link loss budget
AS-3 Fiber Optics and Applied Photonics Committee
This document defines a quantified means of specifying a digital fiber optic link loss budget: Between end users and system integrators Between system integrators and subsystem suppliers Between subsystem suppliers and component vendors The standard specifies methods and the margin required for categories of links
AS-3 Fiber Optics and Applied Photonics Committee
This document draws from, summarizes, and explains existing broadly accepted engineering best practices. This document defines the process and procedure for application of various best practice methods. This document is specifically intended as a standard for the engineering practice of development and execution of a link loss power budget for a general aerospace system related digital fiber optic link. It is not intended to specify the values associated with specific categories or implementations of digital fiber optic links. This document is intended to address both existing digital fiber optic link technology and accommodate new and emerging technologies. The proper application of various calculation methods is provided to determine link loss power budget(s), that depend on differing requirements on aerospace programs. A list of parameters is provided as guidance for aerospace fiber optics applications along with a check list to help assure that appropriate parameters and
AS-3 Fiber Optics and Applied Photonics Committee
Within the heavy commercial vehicle sector, fleet availability stands as a crucial factor impacting the productivity and competitiveness of companies. Despite this, the core element of maintenance strategies applied in the sector still relies solely on mileage or component usage time. On the other hand, the evolution of the industry, particularly the advancement of Industry 4.0 enabling technologies such as sensorization embedded in components, now provides a vast amount of operational data. The severity levels of application, driving style influence, and vehicle operating conditions can be indicated through the treatment of these data. However, there is still little practical application of using this data for effective decision-making regarding maintenance strategy in the sector, correlating the severity level with component failure possibility. Seeking a disruptive approach to this scenario where data analysis supports decisions related to component maintenance strategy, a
de Moraes Seixas, Ricardo
The present study explores the performance of high-density polyethylene (HDPE) pyrooil and ethanol blends with gasoline in SI engine using statistical modeling and analysis using response surface methodology (RSM) and the Anderson–Darling (AD) residual test. The pyrooil was extracted from HDPE through pyrolysis at 450°C and then distilled to separate the liquid fraction. Two blends were prepared by combining pyrooil and gasoline, and pyrooil–ethanol mixture (volume ratio of 9:1) and gasoline, both at volumetric concentrations ranging from 2% to 8% to evaluate brake thermal efficiency (BTE) and specific fuel consumption (SFC) in a SI engine. An experimental matrix containing speed, torque, and blend ratio as independent variables for both blends were designed, analyzed, and optimized using the RSM. The results show that a 4% blend of pyrooil with gasoline (P4) and a 6% blend of pyrooil–ethanol mixture with gasoline (P6E) were optimum for an SI engine. Also, the experimental findings
Manickavelan, K.Sivaganesan, S.Sivamani, S.Kulkarni, Mithun V.
Typically, machine learning techniques are used to realise autonomous driving. Be it as part of environment recognition or ultimately when making driving decisions. Machine learning generally involves the use of stochastic methods to provide statistical inference. Failures and wrong decisions are unavoidable due to the statistical nature of machine learning and are often directly related to root causes that cannot be easily eliminated. The quality of these systems is normally indicated by statistical indicators such as accuracy and precision. Providing evidence that accuracy and precision of these systems are sufficient to guarantee a safe operation is key for the acceptance of autonomous driving. Usually, tests and simulations are extensively used to provide this kind of evidence. However, the basis of all descriptive statistics is a random selection from a probability space. A major challenge in testing or constructing the training and test data set is that this probability space is
Wiesbrock, Hans WernerGrossmann, Jürgen
In the realm of transportation science, the advent of deep learning has propelled advancements in predicting longitudinal driving behavior. This study explores the application of deep neural network architectures, specifically long–short-term memory (LSTM) and convolutional neural networks (CNNs), recognized for their effectiveness in handling sequential data. Using a 3-s temporal window that includes past vehicle progress, speed, and acceleration, the proposed model, a hybrid LSTM–CNN architecture, predicts the vehicle’s speed and progress for the next 6 s. The approach achieves state-of-the-art performance, particularly within a 4 s horizon, but remains competitive even for longer-term predictions. This is achieved despite the simplicity of its input space, which does not include information about vehicles other than the target vehicle. As a result, while its performance may decrease slightly for longer-term predictions due to the lack of environmental information, it still offers
Lucente, GiovanniMaarssoe, Mikkel SkovKahl, IrisSchindler, Julian
In 2023, the European Union set more ambitious targets for reducing greenhouse gas emissions from passenger cars: the new fleet-wide average targets became 93.6 g/km for 2025, 49.5 g/km in 2030, going to 0 in 2035. One year away from the 2025 target, this study evaluates what contribution to CO2 reduction was achieved from new conventional vehicles and how to interpret forecasts for future efficiency gains. The European Commission’s vehicle efficiency cost-curves suggest that optimal technology adoption can guarantee up to 50% CO2 reduction by 2025 for conventional vehicles. Official registration data between 2013 and 2022, however, reveal only an average 14% increase in fuel efficiency in standard combustion vehicles, although reaching almost 23% for standard hybrids. The smallest gap between certified emissions and best-case scenarios is of 14 g/km, suggesting that some manufacturers’ declared values are approaching the optimum. Yet, the majority of vehicles do not appear to fully
Komnos, DimitriosNur, JamilTansini, AlessandroKtistakis, Markos AlexandrosSuarez, JaimeKrause, JetteFontaras, Georgios
The present study discusses the determination of the Seal drag force in the application where an elastomeric seal is used with a metallic interface in the presence of different fluids. An analytical model was constructed to predict the seal drag force and an experimental test was performed to check the fidelity of the analytical model. A Design of Experiment (DoE) was utilized to perform an experimental test considering different factors affecting the Seal drag force. Statistical tools such as the Test for Equal Variances and One Way Analysis of Variance (ANOVA) were used to draw inferences for the population based on samples tested in the DoE test. It was observed that Glycol fluids lead to lubricant wash-off resulting in increased seal drag force. Additionally, non-lubricated seals tend to show higher seal drag force as compared to lubricated seals
Yarolkar, MakrandTelore, MilindPatil, Sandip
A structural load estimation methodology was developed for RLV-TD HEX-01 hypersonic experimental mission, the maiden winged body technology demonstrator vehicle of ISRO. Primarily the method evaluates time history of station loads considering effects of vehicle dynamics and structural flexibility. Station loads of critical structures are determined by superposition of quasi-static aerodynamic loads, dynamic inertia loads, control surface loads and propulsion loads based on actual physics of the system, improving upon statistical load combination approaches. The technique characterizes atmospheric regime of flight from vehicle loads perspective and ensures adequate structural margin considering atmospheric variations and system level perturbations. Features to estimate change in loads due to wind variability and atmospheric turbulence are incorporated into the load estimation methodology. Augmentation in loads due to structural flexibility is assessed along the trajectory using vehicle
Jayan, MahindPavanasam, Ashok GandhiDaniel, Sajan
Aluminum and its alloys entered a main role in the engineering sectors because of their applicable characteristics for indispensable applications. To enhance requisite belongings for the components, the composition of variant metal/nonmetal with light metal alloys is essential in the manufacturing industries. To enhance the wear resistance with significant strength property of the aluminum alloy 2024, the reinforcement SiC and fly ash (FA) were added with the designation Al2024 + 10% SiC; Al2024 + 5% SiC + 5% FA; and Al2024 + 10% FA via stir-casting technique. The wear resistance property of the composites was tested in pin-on-disc with a dry-sliding wear test procedure. The experiment trials were designed in Box–Behnken design (BBD) by differing the wear test parameters like % of reinforcement, sliding distance (m), and load (N). The wear tests on casted samples were carried out at the constant velocity of 2 m/sec, such that the corresponding wear rate for the experiment trials was
Sivakumar, N.Sireesha, S. C.Raja, S.Ravichandran, P.Sivanesh, A. R.Aravind Kumar, R.
The objectives of this study were to provide insights on how injury risk is influenced by occupant demographics such as sex, age, and size; and to quantify differences within the context of commonly-occurring real-world crashes. The analyses were confined to either single-event collisions or collisions that were judged to be well-defined based on the absence of any significant secondary impacts. These analyses, including both logistic regression and descriptive statistics, were conducted using the Crash Investigation Sampling System for calendar years 2017 to 2021. In the case of occupant sex, the findings agree with those of many recent investigations that have attempted to quantify the circumstances in which females show elevated rates of injury relative to their male counterparts given the same level bodily insult. This study, like others, provides evidence of certain female-specific injuries. The most problematic of these are AIS 2+ and AIS 3+ upper-extremity and lower-extremity
Dalmotas, DainiusChouinard, AlineComeau, Jean-LouisGerman, AlanRobbins, GlennPrasad, Priya
For taking counter measures in advance to prevent accidental risks, it is of significance to explore the causes and evolutionary mechanism of ship collisions. This article collects 70 ship collision accidents in Zhejiang coastal waters, where 60 cases are used for modeling while 10 cases are used for verification (testing). By analyzing influencing factors (IFs) and causal chains of accidents, a Bayesian network (BN) model with 19 causal nodes and 1 consequential node is constructed. Parameters of the BN model, namely the conditional probability tables (CPTs), are determined by mathematical statistics methods and Bayesian formulas. Regarding each testing case, the BN model’s prediction on probability of occurrence is above 80% (approaching 100% indicates the certainty of occurrence), which verifies the availability of the model. Causal analysis based on the backward reasoning process shows that H (Human error) is the main IF resulting in ship collisions. The causal chain that maximizes
Tian, YanfeiQiao, HuiHua, LinAi, Wanzheng
Items per page:
1 – 50 of 2257