bluuebunny/crossref_metadata_2025 huggingface dataset:
A Control-Oriented Jet Ignition Combustion Model for an SI Engine
Authors: Song Ruitao , Gentz Gerald , Zhu Guoming , Toulson Elisa , Schock Harold
Published: January 2016

A turbulent jet ignition system of a spark ignited (SI) engine consists of pre-combustion and main-combustion chambers, where the combustion in the main-combustion chamber is initiated by turbulent jets of reacting products from the pre-combustion chamber. If the gas exchange and combustion processes are accurately controlled, the highly distributed ignition will enable very fast combustion and improve combustion stability under lean operations, which leads to high thermal efficiency, knock limit extension, and near zero NOx emissions. For model-based control, a precise combustion model is a necessity. This paper presents a control-oriented jet ignition combustion model, which is developed based on simplified fluid dynamics and thermodynamics, and implemented into a dSPACE based real-time hardware-in-the-loop (HIL) simulation environment. The two-zone combustion model is developed to simulate the combustion process in two combustion chambers. Correspondingly, the gas flowing through the orifices between two combustion chambers is divided into burned and unburned gases during the combustion process. The pressure traces measured from a rapid compression machine (RCM), equipped with a jet igniter, are used for initial model validation. The HIL simulation results show a good agreement with the experimental data.
Estimation of Lithium-Ion Concentrations in Both Electrodes of a Lithium-Ion Battery Cell
Authors: Dey Satadru , Ayalew Beshah , Pisu Pierluigi
Published: January 2016

For control and estimation tasks in battery management systems, the benchmark Li-ion cell electrochemical pseudo-two-dimensional (P2D) model is often reduced to the Single Particle Model (SPM). The original SPM consists of two electrodes approximated as spherical particles with spatially distributed Li-ion concentration. However, the Li-ion concentration states in these two-electrode models are known to be weakly observable from the voltage output. This has led to the prevalent use of reduced models in literature that generally approximate Li-ion concentration states in one electrode as an algebraic function of that in the other electrode. In this paper, we remove such approximations and show that the addition of the thermal model to the electrochemical SPM essentially leads to observability of the Li-ion concentration states in both electrodes from voltage and temperature measurements. Then, we propose an estimation scheme based on this SPM coupled with lumped thermal dynamics that estimates the Li-ion concentrations in both electrodes. Moreover, these Li-ion concentration estimates also enable the estimation of the cell capacity. The estimation scheme consists of a sliding mode observer cascaded with an Unscented Kalman filter (UKF). Simulation studies are included to show the effectiveness of the proposed scheme.
Energy Management Control of a Hybrid Electric Vehicle by Incorporating Powertrain Dynamics
Authors: Bidarvatan Mehran , Shahbakhti Mahdi
Published: January 2016

Energy management strategies in parallel Hybrid Electric Vehicles (HEVs) usually ignore effects of Internal Combustion Engine (ICE) dynamics and rely on static maps for required engine torque-fuel efficiency data. It is uncertain how neglecting these dynamics can affect fuel economy of a parallel HEV. This paper addresses this shortcoming by investigating effects of some major Spark Ignition (SI) engine dynamics and clutch dynamics on torque split management in a parallel HEV. The control strategy is implemented on a HEV model with an experimentally validated, dynamic ICE model. Simulation results show that the ICE and clutch dynamics can degrade performance of the HEV control strategy during the transient periods of the vehicle operation by 8.7% for city and highway driving conditions in a combined common North American drive cycle. This fuel penalty is often overlooked in conventional HEV energy management strategies. A Model Predictive Control (MPC) of torque split is developed by incorporating effects of the studied influencing dynamics. Results show that the integrated energy management strategy can improve the total energy consumption of HEV by more than 6% for combined Urban Dynamometer Driving Schedule (UDDS) and Highway Fuel Economy Driving Schedule (HWFET)drive cycles.
Impulse Redirection of a Tethered Projectile
Authors: Faraji Hossein , Veile Stephanie , Hemleben Samantha , Zaytsev Pavel , Wright Joel , Luchsinger Hans , Hatton Ross L.
Published: January 2016

The momentum of a projectile in free flight can be redirected by using a tether to create a “virtual wall” against which it bounces. The direction of this bounce can be controlled actively through braking modulation, or passively through placement of the tether anchor and the orientation of the projectile at impact. In this paper, we explore the space of motions achievable through the latter two methods. In particular, we consider the ways in which holding the tether away from center of mass at different angles can contribute to changes in speed and direction of motion after the bounce.
Robust Gain-Scheduling Output Feedback Control With Noisy Scheduling Parameters
Authors: Al-Jiboory Ali Khudhair , Zhu Guoming
Published: January 2016

Robust Gain-Scheduling (RGS) control strategy has been considered in this paper. In contrast to the conventional gain-scheduling synthesis methods, the scheduling parameters are assumed to be inexactly measured. This is a practical assumption since measurement noise is inevitable even with very accurate sensors. Multi-simplex modeling approach was used to model the scheduling parameters and their uncertainties in a convex domain. Sufficient conditions in terms of Parametrized Linear Matrix Inequalities (PLMIs) for synthesizing dynamic output-feedback controllers are derived. The resulting controller not only guarantees robust stability and H2 performance but also ensures robustness against scheduling parameters uncertainties. The effectiveness of the developed conditions is demonstrated through numerical example with simulation and comparisons with existing approaches from literature. The comparison results confirm that the developed approach outperforms the existing ones considerably.
Effective Component Tuning in a Diesel Engine Model Using Sensitivity Analysis
Authors: Salehi Rasoul , Stefanopoulou Anna
Published: January 2016

Error propagation and accumulation is a common problem for system level engine modeling at which individually modeled components are connected to form a complete engine model. Engines with exhaust gas recirculation (EGR) and turbocharging have components connected in a feedback configuration (the exhaust conditions affect the intake and the intake, consequently, affects the exhaust), thus they have a challenging model tuning process. This paper presents a systematic procedure for effective tuning of an engine air-charge path model to improve accuracy at the system level as well as reducing the computational complexity of tuning a large set of components. Based on using sensitivity analysis, the presented procedure is used to inspect which component influences more a set of selected outputs in a model with high degree of freedom caused by many parameters of different components. After selecting the influential component, which is the turbocharger in this study, further tuning is applied to parameters in the component to increase the overall accuracy of the complete engine model. The corrections applied to the air-charge path model of a 6 cylinder 13L heavy duty diesel engine with EGR and twin-scroll turbocharger was shown to effectively improve the model accuracy.
High-Fidelity Modelling of an Electric Vehicle
Authors: Kim Shinhoon , Azad Nasser L. , McPhee John
Published: January 2016

The development and validation of a high-fidelity dynamics model of an electric vehicle is presented. The developed model is comprised of two subsystems: i) the vehicle dynamics model, and ii) the electrical powertrain subsystem consists of the alternating-current (AC) induction motor, the 3-phase pulse-width-modulation (PWM) inverter, and the motor controllers. At each stage of the development, the developed models are verified by studying their simulation results. Also, vehicle testing is performed using a reference electric vehicle and experimental powertrain data is measured from the vehicle’s electrical powertrain controller area network (CAN) bus. The experimental motor torque-speed curves are used to tune the AC electric motor model parameters. Once the individual components are developed and validated, the high-fidelity electric vehicle system model is created by assembling the MapleSim vehicle dynamics model and the electrical powertrain subsystem. The simulation results, such as the vehicle’s longitudinal speed and developed motor torque and currents, are presented and studied to verify that the electric vehicle system can operate under different driving scenarios. The high-fidelity electric vehicle model will be used in future work to test and validate new power management controllers.
Dynamics Modeling of Clamping System Considering Characteristics of the Clamping Contact Surface
Authors: Zhao Yanmin , Zhang Jianfu , Feng Pingfa , Ma Yuan
Published: January 2016

The dynamic characteristics of the clamping system, which is composed of workpiece and chuck, have important effects on the stability of turning process. However, in current researches on cutting stability, the influence of the characteristics of clamping contact surface on the clamping system was rarely considered. In order to improve the prediction accuracy of stable cutting limits in turning process, the role of clamping contact surface in deciding the dynamics of the clamping system was analyzed in this paper. Then, the dynamics model of clamping system was established considering the characteristics of clamping contact surface between workpiece and chuck. The dynamics parameters of the clamping system were obtained with receptance coupling substructure analysis method. The frequency response function of clamping system at different cutting position was presented, which is a foundation for analyzing the cutting stability.
Maximizing Average Power Output of an Airborne Wind Energy Generator Under Parametric Uncertainties
Authors: Kehs Michelle A. , Vermillion Chris , Fathy Hosam K.
Published: January 2016

This paper presents a controller for maximizing the time-averaged power output from an airborne wind energy generator in uncertain wind conditions. This system’s optimal energy output often involves flying in periodic figure-8 trajectories, but the precise optimal figure-8 shape is sensitive to environmental conditions, including wind speed. The literature presents controllers that are able to adapt to uncertainties, and this work expands on the current literature by using an extremum seeking based method. Extremum seeking is particularly well-suited for this application because of its well understood stability properties. In this work, extremum seeking is used to search through a family of optimal trajectories (computed offline) that correspond to discrete wind speeds. The controller is efficient in that it only searches for the optimum trajectory over the uncertain parameter (in this paper, wind speed). Results show that the controller converges to the optimal trajectory, provided it is initialized to a stable figure-8. The speed of convergence is dependent on the difference between the initial average power output and the optimal average power output.
A Model Predictive Repetitive Process Control Formulation for Additive Manufacturing Processes
Authors: Sammons Patrick M. , Bristow Douglas A. , Landers Robert G.
Published: January 2016

Additive Manufacturing (AM) processes are a class of manufacturing processes in which parts are fabricated in a layer-by-layer fashion. The layer-by-layer fabrication method creates layer-to-layer dynamics. Implementing process control that neglects the layer-to-layer dynamics can lead to process instability. While repetitive process controllers which utilize only layer-to-layer feedback are a viable method, their usefulness is limited in that they are not well-suited for tracking non-periodic layer-domain references. However, since the entire reference signal is typically known a priori in AM process fabrications, a predictive control methodology can be useful for controlling fabrications in which the reference signal is non-periodic. In this paper a model predictive control formulation is extended to two-dimensions and utilized for repetitive process control Simulation results comparing open-loop and controlled fabrications for a Laser Metal Deposition process are given.
State Emulator-Based Adaptive Architectures for Resilient Networked Multiagent Systems Over Directed and Time-Varying Graphs
Authors: De La Torre Gerardo , Yucelen Tansel
Published: January 2016

In this paper, we present adaptive architectures for networked multiagent systems operating over directed networks to achieve resilient coordination in the presence of disturbances. Specifically, we consider a class of unforeseen adverse conditions consisting of persistent exogenous disturbances and present a state emulator-based distributed adaptive control architecture to retrieve the nominal networked multiagent system behavior. The stability properties of the proposed architecture are analyzed using results from Lyapunov stability and matrix mathematics. Illustrative numerical examples are provided to demonstrate the theoretical findings.
Numeric and Analytic Investigations of Mean-Square Exponential Stability for Stochastically Timed Systems
Authors: Poulsen Dylan , Gravagne Ian , Davis John M.
Published: January 2016

This paper is motivated by the problems posed in feedback control design when actuators, sensors, and/or computational nodes connect via unreliable or unpredictable communications channels. In these cases, there is a degree of stochastic uncertainty to the timing of the system’s discretizing elements, such as digital-to-analog converters. Several theorems related to the stability of non-uniformly sampled discrete dynamical systems have recently been proposed; here we examine through numeric investigation the characteristics of systems which are mean square exponentially stable (MSES). In particular we present a method to compute the range of mean and variance that a nonuniformly discretized feedback control system may tolerate while remaining MSES. Several examples are presented.
Vibration Energy Harvesting System With Mechanical Motion Rectifier
Authors: Liang Changwei , Wu You , Zuo Lei
Published: January 2016

Mechanical motion rectifier (MMR) has been used as power takeoff system to harvest energy for different applications. The dynamics of single degree of freedom energy harvesting system with MMR is piecewise linear due to the engagement and disengagement of one-way clutches. The energy harvesting performance of single degree of freedom system with MMR under force and motion excitation are studied and compared with ideal linear damping and non-MMR system in this paper. Under harmonic force and motion excitation, the optimal excitation frequency and output power of MMR system is less sensitive to the power takeoff inertia compared with non-MMR system. Furthermore, the output power of MMR system under harmonic motion excitation is larger than non-MMR system. The performance index of MMR, non-MMR and linear damping systems are compared under random excitation. It is found that MMR system has a better performance over both non-MMR and linear damping system, which makes it a better choice for energy harvesting.
A New Approach to Reduce Engine-Out Emissions Enabled by Trajectory-Based Combustion Control
Authors: Zhang Chen , Sun Zongxuan
Published: January 2016

Previously, the authors have proposed the concept of piston trajectory-based combustion control enabled by free piston engines (FPE). With this novel control method, the FPE realizes in-cycle real-time combustion control, in terms of adjusting the ignition timing and manipulating the in-cylinder temperature trace, through various piston trajectories and achieves higher thermal efficiency compared to the conventional internal combustion engines. In this paper, the effects of this new combustion control on engine-out emissions are studied. First, a model is developed that includes different piston trajectories in the FPE, a convective heat loss sub model and a reduced n-heptane reaction mechanism with major emissions species from diesel engines. Afterwards, a new approach which reduces the engine-out emissions by employing novel piston trajectories is described. At last, analyses of the simulation results demonstrating the variable piston trajectories’ effects on CO and NOx emissions are presented, which further reveal the advantages of the trajectory-based combustion control.
Wheel-Slip Based Inverse Solution for Differential Drive Mobile Robots
Authors: Whitman Alan , Clayton Garrett , Poultney Alex , Ashrafiuon Hashem
Published: January 2016

An approximate inverse dynamic solution for differential drive mobile robots is presented where the wheel speeds are analytically calculated for a specified desired trajectory. The differential equations of motion of the mobile robot are nondimen-sionalized and a small parameter is defined based on the ratio of wheel slip and wheel speed variation time scales. Approximate dominant and first order inverse solutions are derived for general trajectories. Next, a trajectory planning strategy is devised to ensure continuous wheel speed profiles in achieving any desired target trajectory. The case of target circular trajectories is specifically considered and with inverse solutions which are verified both through simulations and experiments.
Design of Mobile Microgrid’s Hierarchy for Power Distribution
Authors: Moridian Barzin , Bennett Daryl , Mahmoudian Nina , Robinett Rush , Weaver Wayne W.
Published: January 2016

This paper presents a hierarchy for autonomous mobile microgrids to ensure robustness and scalability of such systems for power distribution applications. Developing an autonomous mobile microgrid based on the proposed hierarchy will create a microgrid system that will autonomously connect to different power nodes (generators, loads, storage units, converters, etc.) and interact with them accordingly. This system will have the scalability characteristics of an ad hoc system and can reconfigure itself depending on available power nodes.
Intelligent Vehicle Fuel Saving Technologies: Comparing Three Primary Categories of Methods
Authors: Fredette Danielle , Jing Junbo , Ozguner Umit
Published: January 2016

In recent years, numerous control algorithms for connected and automated vehicles have emerged which focus on modifying driving strategy in order to reduce fuel usage. Referred to as “dynamic eco-driving,” these technologies have realized the possibility for additional fuel savings by utilizing information technologies rather than mechanics. The exact methodologies, however, are diverse. Three primary categories of dynamic eco-driving methodologies are identified and described: 1) ad-hoc methods, designed for the purpose of saving fuel but not considering optimality, 2) classical optimization methods, which use fuel usage modeling to solve an optimal control problem forwards in time, whether numerically or analytically, and 3) optimization by dynamic programming, in which a fuel usage-oriented cost function is minimized but solved backwards in time in discrete steps. Representatives from each of these categories are studied and implemented in simulation for comparison. Advantages and disadvantages of each relative to multiple performance measures are discussed.
A Soft-Sensing Technique for Measurement of Mass Flow Rate in a Liquid-Liquid Heat Exchanger
Authors: Nundy Sangeeta , Mukhopadhyay Siddhartha , Deb Alok Kanti
Published: January 2016

This paper presents a soft-sensing technique of determining the mass flow rate of a liquid-liquid heat exchanger using temperature measurements and a distributed parameter model. The efficiency of a heat exchanger is intimately related to its mass flow rate and as a consequence mass flow rate measurements are essential for any fault detection or monitoring program of the heat exchanger. However the costly mass flow rate sensor measurements can be bypassed by this soft-sensing technique which primarily employs measurements from inexpensive temperature sensors. We first develop a distributed parameter model of the counter flow type heat exchanger using energy balance equations. Thereafter, a state-space model of the heat exchanger is formulated using orthogonal collocation method where temperature at the collocation points and the unknown mass flow rate are considered as the state variables. The mass flow rate is estimated by a Hybrid Extended Kalman Filter algorithm using the outlet temperature measurements. The sensitivity of the soft-sensing technique in presence of modeling errors and measurement noise is also studied using a suitable simulation example.
A Phenomenological Model for Predicting the Combustion Phasing and Variability of Spark Assisted Compression Ignition (SACI) Engines
Authors: Prakash Niket , Martz Jason B. , Stefanopoulou Anna G.
Published: January 2016

An advanced combustion mode, Spark Assisted Compression Ignition (SACI) has shown the ability to extend loads relative to Homogenous Charge Compression Ignition (HCCI) combustion but at reduced fuel conversion efficiency. SACI combustion is initiated by a spark, with flame propagation followed by a rapid autoignition of the remaining end-gas fuel fraction. Extending upon previous work [1,2], the Wiebe function coefficients used to fit the two combustion phases are regressed here as functions of the air path variables and actuator settings. The parameterized regression model enables mean-value modeling and model-based combustion phasing control. SACI combustion however, exhibits high cyclic variability with random characteristics. Thus, combustion phasing feedback control needs to account for the cyclic variability to correctly filter the phasing data. This paper documents the success in regressing the cyclic variability (defined as the standard deviation in combustion phasing) at various operating conditions, again as a function of air path variables and actuator settings. The combination of the regressed mean and standard deviation models is a breakthrough in predicting the mean-value engine behavior and the random statistics of the cycle-to-cycle variability.
Model Predictive Control for Energy Maximization of Small Vertical Axis Wind Turbines
Authors: Onol A. O. , Sancar U. , Onat A. , Yesilyurt S.
Published: January 2016

In this paper, a model predictive control (MPC) approach is presented to maximize the energy generated by a small vertical axis wind turbine (VAWT) subject to current and voltage constraints of electrical and power electronic components. Our method manipulates a load coefficient and optimizes the control trajectory over a prediction horizon such that a cost function that measures the deviation from the maximum available energy and the violation of current and voltage constraints is minimized. Simplified models for the VAWT and a permanent magnet generator have been used. A number of simulations have been carried out to demonstrate the performance of the proposed method at step and oscillatory wind conditions. Furthermore, impacts of the constraints on energy generation have been investigated. Moreover, the performance of the MPC has been compared with a typical maximum power point tracking algorithm in order to show that maximizing the instantaneous power does not mean maximizing the energy; and simulation results have shown that the MPC outperforms the maximum power point tracking algorithm in terms of generated energy by allowing deviations from the maximum power instantaneously for future gains in energy generation.
Thermal Management and Voltage Stabilization in Air-Forced Open-Cathode Fuel Cells
Authors: Lotfi N. , Zomorodi H. , Landers R. G.
Published: January 2016

Temperature control is undoubtedly one of the important challenges in open-cathode fuel cell systems. Due to cost considerations, it is traditionally achieved by constant-speed operation of the fans. In this paper, a state feedback temperature controller, combined with a Kalman filter to mitigate the noisy temperature measurements is designed and implemented. The controller-filter set facilitates robust thermal management with respect to model uncertainties and measurement noise. The proposed temperature control not only manages to track the fuel cell temperature reference, it can also be used to stabilize the output voltage. Voltage regulation is of great importance for open-cathode fuel cells as it guarantees a predictable and fixed fuel cell output voltage for given current values in spite of internal and external disturbances. The controllers were implemented experimentally and the results show promising performances in regulating the reference temperature and voltage despite model uncertainties and disturbances.
Coordinated Rate Control of a Hydraulic Excavator Using Traditional Joystick Hardware
Authors: Seifert Samuel F. , Book Wayne J.
Published: January 2016

This paper presents a novel user interface (UI) for coordinated rate control (CRC) of an excavator end effector using traditional hardware. Coordinated control of an excavator end effector alleviates the cognitive load created by nonlinear arm dynamics on the excavator operator, allowing the operator to perform tasks more quickly and with fewer errors. A human subject experiment demonstrates the feasibility of excavator CRC using the traditional twin joystick setup, and compares operator performance between a CRC UI and traditional excavator UI. Performance of the CRC UI was statically equivalent to the performance of the traditional UI. When asked to self-report UI preference: 26 participants stated they preferred the CRC UI, 6 preferred the traditional UI, and 14 had no preference. Although the current iteration of the CRC UI offered no measurable performance improvements, a remapping of the CRC joystick inputs to the end effector motion could make the CRC UI more intuitive, lead to better performance metrics, and make hydraulic excavators safer, more efficient, and easier to use.
Full-Order Distributed Fault Diagnosis for Large-Scale Nonlinear Stochastic Systems
Authors: Noursadeghi Elaheh , Raptis Ioannis
Published: January 2016

This paper deals with the problem of designing a distributed fault detection and isolation algorithm for nonlinear large-scale systems that are subjected to multiple fault modes. To solve this problem, a network of detection nodes is deployed to monitor the monolithic system. Each node consists of an estimator with partial observation of the system’s state. The local estimator executes a distributed variation of the particle filtering algorithm; that process the local sensor measurements and the fault progression model of the system. In addition, each node communicates with its neighbors by sharing pre-processed information. The communication topology is defined using graph theoretic tools. The information fusion between the neighboring nodes is performed by a distributed average consensus algorithm to ensure the agreement on the value of the local estimates. The simulation results demonstrate the efficiency of the proposed approach.
A Control Strategy for an Active Alignment Transtibial Prosthesis
Authors: LaPrè Andrew , Sup Frank
Published: January 2016

This paper presents a control approach for an experimental transtibial prosthesis that can actively realign the residual limb in relation to prosthetic foot during the stance phase of gait. The realignment objective is to inject positive power into the gait cycle while actively reducing the magnitude of the sagittal moment transferred to the residual limb. The altered gait dynamics of this new type of prosthesis require a control approach that coordinates its function with a user’s gait cycle. This paper overviews the mechanical design of the prosthesis development, the proposed finite-state adaptive controller, and presents experimental results for constant cadence walking and adaptation while changing walking speeds.
Extremum Seeking Based Control Strategy for a Chilled-Water Plant With Parallel Chillers
Authors: Mu Baojie , Li Yaoyu , Salsbury Timothy I. , House John M.
Published: January 2016

Chilled-water plants with multiple chillers are the backbone of ventilation and air conditioning (VAC) systems for commercial buildings. A penalty function based multivariate extremum seeking control (ESC) strategy is proposed in this paper for maximizing the energy efficiency in real time for a variable primary flow (VPF) chilled-water plant with parallel chillers. The proposed ESC algorithm takes the total power consumption (chiller compressors + cooling tower fan + condenser water pumps + penalty terms if inputs saturation occurs) as feedback, and tower fan air flow, condenser water flows and evaporator leaving chilled-water temperature setpoint as plant inputs (ESC outputs). A band-pass filter array is used in place of the conventional high-pass filter at the plant output so as to reduce the cross-channel interference. Chiller sequencing is also enabled with input saturation related signals. A Modelica based dynamic simulation model is developed for a chilled-water plant with two parallel chillers, one cooling tower, one air-handling unit and one zone. Simulation results under several testing conditions validate the effectiveness of the proposed model-free control strategy, as well as the significant energy saving.
Two-Stage Design of Linear Feedback Controllers for a Proton Exchange Membrane Fuel Cell
Authors: Radisavljevic-Gajic Verica , Rose Patrick , Clayton Garrett M.
Published: January 2016

The paper considers the eighth-order proton exchange membrane (PEM) fuel-cell mathematical model and shows that it has a multi-time scale property, indicating that the dynamics of three model state space variables operate in the slow time scale and the dynamics of five state variables operate in the fast time scale. This multi-scale nature allows independent controllers to be designed in slow and fast time scales using only corresponding reduced-order slow (of dimension three) and fast (of dimension five) sub-models. The presented design facilitates the design of hybrid controllers, for example, the linear-quadratic optimal controller for the slow subsystem and the eigenvalue assignment controller for the fast subsystem. The design efficiency and its high accuracy are demonstrated via simulation on the considered PEM fuel cell model.
Prediction of Periventricular Leukomalacia Occurrence in Neonates Using a Novel Support Vector Machine Classifier Optimization Method
Authors: Bender Dieter , Jalali Ali , Licht Daniel J. , Nataraj C.
Published: January 2016

Prior work has documented that Support Vector Machine (SVM) classifiers can be powerful tools in predicting clinical outcomes of complex diseases such as Periventricular Leukomalacia (PVL). Our previous study showed that SVM performance can be improved significantly by optimizing the supervised training set used during the learning stage of the overall SVM algorithm. This study fully develops the initial idea using the reliable Leave-One-Out Cross-validation (LOOCV) technique. The work presented in this paper confirms previous results and improves the performance of the SVM even further. In addition, using the LOOCV technique, the computational time is decreased and the structure of the algorithm simplified, making this framework more feasible. Furthermore, we evaluate the performance of the resulting optimized SVM classifier on an unseen set of data. This demonstrates that the developed SVM algorithm outperforms normal SVM type classifiers without any loss of generalization.
Evaluation of a Multi-Vehicle Merging Strategy Under Different Lateral Maneuvers in the Presence of Sudden Braking
Authors: Goli Mohammad , Eskandarian Azim
Published: January 2016

The ability for multiple vehicles to merge into an ongoing platoon is an important task in the field of intelligent transportation system (ITS). For such task, first a strategy is required to include a set of rules and actions which allows the incoming vehicles to join the platoon, and second; a safe lateral trajectory generator which always ensures the safety of lateral maneuver in terms of lateral acceleration. In this paper we evaluated the multi-vehicle merging strategy using different lateral trajectory functions under sudden breaking. Simulation results show that for merging task, a switching function is necessary to switch from an adaptive lateral function to a constant lateral trajectory function in case of sudden decelerations.
Comparing the Identification of Sites With High Risk of Landslides Using Isohyets of Precipitation vs Alterations of Rainfall by La Niña in Santander Colombia
Authors: Gutiérrez Juan David
Published: January 2016

Extreme meteorological events associated with climate change are a real issue and have important impact over the economy of infrastructure sector, including highways, hydrocarbon transport by pipelines, mines, etc., because saturation of soils by water can produce landslides and it could produce the fracture of pipelines or other kind of tangible assets. For example, an assessment of historical geotechnical failures in Ecopetrol (Colombian Oil Company) vs. extreme meteorological events shows that during La Niña (extreme rainfall period) geotechnical failures are three times greater. This work shows a method to identify places of risk by extreme meteorological events, mainly La Niña phenomenon, with focus in most probably alteration of rainfall. Our results illustrate the hot spots where there is a high probability of slight excess (120–160% of average rainfall) and high excess (>160%) of average rainfall. The results were intersected in a GIS with pipelines and mass movement risk maps to identify the places of high risk along Santander region.
Analysis of Strain Sensor Cable Models and Effective Deployments for Distributed Fiber Optical Geotechnical Monitoring System
Authors: DuToit Dana , Ryan Kent , Rice John , Bay James , Ravet Fabien
Published: January 2016

Long range, distributed fiber optic sensing systems have been an available tool for more than a decade to monitor pipeline subsidence integrity challenges. Effective deployment scenarios are an important decision to be factored into the selection of this monitoring equipment and typologies relative to specific project needs. In an effort to analyze the effectiveness of various fiber optic deployment conditions, a controlled field experiment was conducted. Within this field experiment, a variety of distributed fiber optic sensors and point sensors were deployed in predefined positions. These positions relative to the pipeline were selected to support a range of deployment needs including new construction or retrofitting of existing pipelines. A 16-inch diameter by 60-meter long epoxy coated pipeline that was capable of being pressurized to mimic operating conditions was utilized. This test pipe was installed in a typical trench setting. Conventional point gauges were installed at key locations on the pipeline. Fiber optic sensor cables were installed at key locations providing 14 alternative scenarios in terms of sensitivity, accuracy, and cost.

After construction of the test pipeline, real time continuous monitoring via the array of conventional and fiber optic sensors commenced. A deep trench was excavated adjacent and parallel to the central portion of the pipeline which began to induce subsidence in the test pipeline. Continued monitoring of the various sensors produced real time visualization of the evolving subsidence. A comparison of the reaction of the sensors is compiled to provide an intelligent selection criteria for integrity managers in terms of accuracy, deployment, and costs for pipeline subsidence monitoring projects. In addition, further analysis of this sensor data should provide more insight into pipeline/soil interaction models and behaviors.
Change Detection Within Pipeline ROWs: Environmental Change Analysis Using High Resolution Satellite Imagery
Authors: Huisman Otto , Gharibi Arash
Published: January 2016

One of the major concerns for pipeline operators is to efficiently monitor the events happening over the pipeline corridor, or right-of-way (ROW). Monitoring of the ROW is an important part of ensuring the safe and efficient transportation of oil and gas. Events occurring within this zone require rapid assessment and, if necessary, mitigation. These events could be physical intrusions such as encroachment from growing settlements, impact of vegetation, pipeline leakage or geo-environmental hazards.

Analysis of satellite imagery can provide an efficient and low cost solution to access and quantify change across the ROW. Examining these events over a periodic interval requires implementation of specific methods that can support the on-going monitoring and decision making practices. In this context, satellite remote sensing images can provide a low cost and efficient solution for monitoring the physical and environmental impacts over the ROW of pipeline system.

This paper reports on the development of a methodological approach for environmental change analysis using high resolution satellite images that can help decision making in pipeline systems. Analysis results and maps produced during this work provide an insight into landcover change over the study area and expected to support in on-going pipeline management practices.

Two methods, Vegetation index differencing and post classification comparison have been implemented to identify change areas in the Taranaki region of the North Island of New Zealand. Vegetation index differencing with NDVI shows increase or decrease of overall vegetation within the study area. Special focus was given on large area increase and decrease with area threshold value above 0.2 hectare.

Detailed analysis of change was conducted with post classification comparison method that uses land cover classification results of year 2010 and 2013. An overall change of 10% has been observed throughout the study area with large area change of approximately 5%. Results obtained from post classification comparison method were further analyzed with 6 focus areas and compared with the existing soil data and rainfall data.

The methods adopted during this study are expected to provide a base for environmental change analysis in similar pipeline corridors to support decision making.
Results of a Mitigation Technique Used to Reduce Pipeline Strains in Unstable Slopes
Authors: Contreras Maria F. , Pereira Ordoñez Mauricio , Hernández Jon , Vergara Carlos
Published: January 2016

The OCENSA pipeline system crosses a wide range of geological zones, finding different stability problems. Those problems related with landslides are stabilized with different kinds of geotechnical works within the pipeline maintenance programs, but sometimes these problems reach big dimensions making very difficult to stabilize them, so mitigation techniques are necessary in order to guarantee the pipe integrity.

A mitigation technique using EPS (Expanded Poly-Styrene) blocks is being used in the OCENSA pipeline system (Colombia) in order to reduce the buried pipe response due to soil displacements during landslide events and in creeping slopes. OCENSA is the first operator in Latin America using this technique. Prior to the use of this technique, numerical modeling studies were done with the support of SOLSIN S.A.S. These studies were focused on determining the viability and effectiveness of the proposed technique.

The purpose of the EPS blocks is to constitute a low-density fill with very low Young modulus reducing the soil-pipeline interaction forces. These blocks are located near the landslide limits in both, the stable and un-stable zones in order to reduce the stiffness of the materials around the pipe. These blocks allow the pipe to move beyond the landslide limits, reducing the bending strains. The extension of the EPS backfill is determined by means of the geotechnical investigation of the place in study and using the in-line inspection tools data to determine the length of the pipe affected by the soil movement.

In this paper, three case studies are presented in which the proposed mitigation technique effectiveness was proved. In this part, data analyses coming from the in line inspection program was done.

The inertial tool data showed that the EPS blocks had a significant effect on the pipe response, reducing the total strains compared with those obtained with a normal backfill. This technique can be used to reduce the frequency of the strain-relief excavations in unstable slopes. That means a cost reduction in the pipe maintenance activities and a more efficient integrity management program.
Characterization of a cold cathode Penning ion source for the implantation of noble gases beneath 2D monolayers on metals: Ions and neutrals
Authors: Cun Huanyao , Spescha Annina , Schuler Adrian , Hengsberger Matthias , Osterwalder Jürg , Greber Thomas
Published: January 2016

Argon ion kinetic energy spectra at different discharge voltages (between 480 and 600 V) of a commercial cold cathode ion source IQP10/63 are reported. The high kinetic energy cut-off depends on the discharge voltage and the corresponding plasma potential due to excess positive charges which is found to be about 136 V. Exposure of single layer hexagonal boron nitride on rhodium to the beam of the ion source leads to the formation of nanotents, i.e., stable atomic protrusions. A positive bias voltage is applied to the target sample to block the positive ions produced by the ion source. However, application of a positive bias potential (800 eV), which is higher than the kinetic energy cut-off, still allows the formation of nanotents and its observation with scanning tunneling microscopy. This indicates that the ion source also produces neutral atoms with kinetic energies higher than the penetration threshold across a single layer of hexagonal boron nitride.
Assessing Novices’ Game Performance in Rugby Union: The Rugby Attack Assessment Instrument (RAAI)
Authors: Llobet-Martí Bernat , López-Ros Victor , Barrera-Gómez Jose , Comino-Ruiz Joel
Published: January 2016

The application of Teaching Games for Understanding (TGfU) and Game Centered Approaches (GCA) in team sports initiation generated the need for assessing game performance. In this paper we introduce the Rugby Attack Assessment Instrument (RAAI), a tool to assess the actions of players in attack and their incidence in the generated game situations in rugby. The RAAI focuses the attention on the ball carrier during a 5 vs. 5 situation. The actions of players in possession of the ball are described and codified. A weight is allocated to each simple and combined action in relation to its tactical value. Thus, the codified actions provide a weighted Index of Performance, the team score of the RAAI. Validity and reliability were tested in two different studies. Results suggest that the RAAI is valid and reliable to assess ball carrier’s actions and their influence in attacking game situations of novice rugby union players.
Linking Teacher Socialization Research With a PETE Program: Insights From Beginning and Experienced Teachers
Authors: MacPhail Ann , Hartley Therese
Published: January 2016

The purpose of this study is to explore the extent to which beginning and experienced teachers differed in their perceptions of shaping school forces and their being shaped by school forces. The findings allow the authors to examine the link between teacher socialization research and practice in a physical education teacher education (PETE) program and to consider the practical (and institutional) changes that may improve the quality of teacher education. Six beginning physical education teachers (BTs) (in their first year of teaching) and six experienced physical education teachers (ETs) (who had been teaching for six years) took part in interviews and completed prompt sheets throughout the duration of a school year. The paper discusses ways in which one PETE program has attempted to use, and plans for future use of, BTs’ and ETs’ accounts of socialization to inform how best to prepare PSTs for the reality of teaching in schools.
Tumor-mediated suppression of T cells is EZ(H2)
Authors: Foley John F.
Published: January 2016

Glucose depletion by tumors suppresses antitumor immunity by reducing the abundance of a methyltransferase in tumor-infiltrating T cells.
Mutational Analysis of Quinolone Resistance Protein QnrVC7 Provides Novel Insights into the Structure-Activity Relationship of Qnr Proteins
Authors: Po Kathy Hiu Laam , Chan Edward Wai Chi , Chen Sheng
Published: January 2016

This study assessed the functional importance of residues located at the i
−2
position of face 4 of the tandem repeat loops of the quinolone resistance protein QnrVC7 through mutagenesis studies. The i
−2
position of face 4 on different coils required residues with different natures. Some substitutions reduced the protective activity of QnrVC7, while some of them increased it. These findings advanced our understanding on the detailed structural organization and functional requirements of Qnr proteins.
Survey of Carbapenemase-Producing Enterobacteriaceae in Companion Dogs in Madrid, Spain
Authors: González-Torralba Ana , Oteo Jesús , Asenjo Alejandra , Bautista Verónica , Fuentes Elisabeth , Alós Juan-Ignacio
Published: January 2016

We found a low prevalence (0.6%) of carbapenemase-producing
Enterobacteriaceae
(CPE) in fecal microbiota of companion dogs. A single VIM-1-producing
Klebsiella pneumoniae
isolate belonging to sequence type (ST) 2090 was detected.
bla
VIM-1
was carried on a class 1 integron and an untypeable ∼48-kb plasmid. Emergence and spread of CPE in this group of animals may be a threat to public health in human and veterinary medicine. This finding supports the need for active surveillance studies in companion animals that live close to humans, as interspecies transmission may occur within the same household.
In Vitro
Antiviral Activity and Resistance Profile Characterization of the Hepatitis C Virus NS5A Inhibitor Ledipasvir
Authors: Cheng Guofeng , Tian Yang , Doehle Brian , Peng Betty , Corsa Amoreena , Lee Yu-Jen , Gong Ruoyu , Yu Mei , Han Bin , Xu Simin , Dvory-Sobol Hadas , Perron Michel , Xu Yili , Mo Hongmei , Pagratis Nikos , Link John O. , Delaney William
Published: January 2016

Ledipasvir (LDV; GS-5885), a component of Harvoni (a fixed-dose combination of LDV with sofosbuvir [SOF]), is approved to treat chronic hepatitis C virus (HCV) infection. Here, we report key preclinical antiviral properties of LDV, including
in vitro
potency,
in vitro
resistance profile, and activity in combination with other anti-HCV agents. LDV has picomolar antiviral activity against genotype 1a and genotype 1b replicons with 50% effective concentration (EC
50
) values of 0.031 nM and 0.004 nM, respectively. LDV is also active against HCV genotypes 4a, 4d, 5a, and 6a with EC
50
values of 0.11 to 1.1 nM. LDV has relatively less
in vitro
antiviral activity against genotypes 2a, 2b, 3a, and 6e, with EC
50
values of 16 to 530 nM.
In vitro
resistance selection with LDV identified the single Y93H and Q30E resistance-associated variants (RAVs) in the NS5A gene; these RAVs were also observed in patients after a 3-day monotherapy treatment.
In vitro
antiviral combination studies indicate that LDV has additive to moderately synergistic antiviral activity when combined with other classes of HCV direct-acting antiviral (DAA) agents, including NS3/4A protease inhibitors and the nucleotide NS5B polymerase inhibitor SOF. Furthermore, LDV is active against known NS3 protease and NS5B polymerase inhibitor RAVs with EC
50
values equivalent to those for the wild type.