bluuebunny/crossref_metadata_2025 huggingface dataset:
Daylight photodynamic therapy with methylene blue in plane warts: a randomized double‐blind placebo‐controlled study
Authors: Fathy Ghada , Asaad Marwa Kamal , Rasheed Haval Mohamad
Published: February 2017

Background

Conventional photodynamic therapy is associated with inconveniently long clinic visits and discomfort during therapy. Daylight‐photodynamic therapy (DL‐PDT) is an effective treatment, nearly pain free and more convenient for both the clinics and patients. There are no published studies of methylene blue (MB) as a photosensitizer (PS) used in DL‐PDT.

Methods

Forty patients had multiple plane warts; 20 patients were subjected to DL‐PDT with topical 10% methylene blue gel, and 20 patients were subjected to DL‐PDT with hematoxylin (placebo). Improvement was evaluated by change of the number of warts and the dermoscope picture.

Results

A total of 20 (100%) patients in group II showed no response to placebo, 13 patients (65%) in group I showed complete clearance, 2 (10%) patients showed a good response, and 5 (25%) patients had poor response to treatment (P < 0.01). No serious side effects and patients tolerated the pain well. No relapse was detected during the follow‐up period (12 months).

Limitation of the study

Daylight exposure was not monitored with a dosimeter.

Conclusion

Daylight‐PDT using MB is safe, easy to carry out, economic, effective, acceptable cosmetic results with no recurrence, convenient especially for children and nearly painless treatment.
There and Back Again: A Tale of the Advocacy Coalition Framework
Authors: Pierce Jonathan J. , Peterson Holly L. , Jones Michael D. , Garrard Samantha P. , Vu Theresa
Published: February 2017

To better understand how the Advocacy Coalition Framework (ACF) is applied, this article catalogues and analyzes 161 applications of the ACF from 2007 to 2014. Building on a previous review of 80 applications of the ACF (1987–2006) conducted by Weible, Sabatier, and McQueen in 2009, this review examines both the breadth and depth of the framework. In terms of breadth, there are over 130 unique first authors from 25 countries, in almost 100 journals applying the framework, including a majority outside of the United States. In terms of depth, a plurality of applications analyzes environment and energy, subsystems at the national level, and utilizes qualitative methods of data collection and analyses. This review also explores how the three theoretical foci of the framework—advocacy coalitions, policy change, and policy‐oriented learning—are applied. Our findings suggest that the ACF balances common approaches for applying the framework with the specificity of particular contexts.
Beyond the thermistor: Novel technology for the ambulatory diagnosis of obstructive sleep apnoea
Authors: Gray Emma L. , Barnes David J.
Published: February 2017

See article, page 567
Estimating South Africa's Output Gap and Potential Growth Rate
Authors: Fedderke Johannes W. , Mengisteab Daniel K.
Published: February 2017

This paper estimates the potential output of the South African economy using several filters. We demonstrate that potential output measures are very sensitive to the different methodologies. We also provide estimates of South Africa's potential growth rate over the 1960–2015 period. Current estimates of the potential growth rate fall in the 1.9%–2.3% range. However, the evidence suggests that the rate is under considerable downward pressure. South African potential growth may be headed toward the 1% range. The strongest decline is in the real sectors of the economy (Manufacturing, Mining), the greatest resilience in the service sectors (financial in particular).
Investigating the level of salivary endothelin‐1 in premalignant and malignant lesions
Authors: Nosratzehi Tahereh , Risbaf Fakour Sirous , Alijani Ebrahim , Salehi Maryam
Published: February 2017

Purpose

This study aimed to investigate the level of salivary endothelin‐1 in premalignant and malignant lesions.

Materials and Methods

In this study, 75 cases were investigated of which 25 cases were healthy, 25 cases had oral lichen planus (OLP), and 25 cases had oral squamous cell carcinoma (OSCC). In order to collect the saliva samples, the unstimulated spitting was used. The samples were collected between 9 and 12 a.m. They were sent to the lab shortly after being collected and salivary endothelin‐1 was recorded for each sample according to the instruction of factory by using enzyme‐linked immunosorbent assay and optical density at a wavelength of 450 nm. SPSS version 20 and one‐way ANOVA and LSD tests were used to analyze the data.

Results

The mean of salivary endothelin‐1 level in patients with OSCC was 163.98 pg/ml, in patients with OLP was 160.9 pg/ml, and in healthy people was 137.19 pg/ml. The analysis of one‐way ANOVA suggested that the level of salivary endothelin‐1 in both groups was the same and significantly higher than that in control group (p < 0.05).

Conclusions

The level of salivary endothelin‐1 in patients with SCC and OLP was higher than that in healthy group. Thus, it can be used as the latest therapeutic protocol for oral premalignant and malignant lesions.
Master Maker: Understanding Gaming Skill Through Practice and Habit From Gameplay Behavior
Authors: Huang Jeff , Yan Eddie , Cheung Gifford , Nagappan Nachiappan , Zimmermann Thomas
Published: February 2017

The study of expertise is difficult to do in a laboratory environment due to the challenge of finding people at different skill levels and the lack of time for participants to acquire mastery. In this paper, we report on two studies that analyze naturalistic gameplay data using cohort analysis to better understand how skill relates to practice and habit. Two cohorts are analyzed, each from two different games (Halo Reach and StarCraft 2). Our work follows skill progression through 7 months of Halo matches for a holistic perspective, but also explores low‐level in‐game habits when controlling game units in StarCraft 2. Players who played moderately frequently without long breaks were able to gain skill the most efficiently. What set the highest performers apart was their ability to gain skill more rapidly and without dips compared to other players. At the beginning of matches, top players habitually warmed up by selecting and re‐selecting groups of units repeatedly in a meaningless cycle. They exhibited unique routines during their play that aided them when under pressure.
Quantitative assessment of haemolysis secondary to modern infusion pumps
Authors: Poder T. G. , Boileau J.‐C. , Lafrenière R. , Thibault L. , Carrier N. , de Grandmont M.‐J. , Beauregard P.
Published: February 2017

Background

Although most studies have shown that little haemolysis is induced by infusion pumps, there are some notable exceptions. Only limited data are available on the actual infusion pumps that are most used in hospitals in Quebec and elsewhere, namely, the Infusomat® Space (peristaltic), Plum A+™ (piston) and Colleague® CXE (shuttle) pumps.

Methods

Haemolysis and potassium levels were compared before and after the use of the three different infusion pumps. Using 135 units of packed red blood cells (RBCs) aged from 10 to 28 days, 27 measurements were taken for each pump at various flow rates (30, 60, 150, 300 and 450 ml/h) and were compared with measurements taken before using the pumps. The range of flow rates was chosen to cover those of paediatric and adult transfusions.

Results

The shuttle‐ and piston‐type pumps resulted in low haemolysis levels. The peristaltic‐type pump produced significantly more haemolysis, which worsened at low flow rates, but the absolute value of haemolysis remained within the range recommended by the regulatory agencies in North America and Europe. Approximately two‐thirds of the haemolysis produced by the peristaltic‐type pump seemed to be secondary to the use of an antisiphon valve (ASV) on the transfusion line recommended by the manufacturer. Potassium levels did not increase with the use of the pumps.

Conclusion

Modern infusion pumps widely used in hospitals in Quebec and elsewhere produce non‐threatening levels of haemolysis during the transfusion of packed RBCs aged from 10 to 28 days. ASVs appear to induce additional haemolysis, and we do not recommend using them for blood transfusion.
Development and Analysis of a Novel Parallel Manipulator Used in Four-Dimensional Radiotherapy
Authors: Arenbeck Henry , Prause Isabel , Abel Dirk , Corves Burkhard
Published: February 2017

Radiotherapy (RT) enables a selective destruction of tumor cells, although the treatment area is limited to the irradiated volume. Any RT technique comes along with multiple sources of error, which can lead to a deviation of the dose that is applied to the patient. Phantoms—structures that replicate a human and include measurement technology to assess the applied dosage—are used to make such errors observable. Past RT-technologies assumed static tumors. Correspondingly, most existing phantoms comprise only static components. Nowadays, RT is at a transition stage toward techniques which explicitly account for physiological motion. These techniques require phantoms generating such motion. Consequentially, a demand for new kinds of manipulators, which operate with a RT-phantom, has come up and will further increase in the future. Key demands of such manipulators are among others, the generation of full rigid body motion, high acceleration, high stiffness, compactness, little weight, and easy portability. Another indispensable feature is the spatial separation of mechatronic components and phantom structure to ensure human equivalency of the latter. In this work, a new kind of parallel kinematic manipulator (PKM), which is tailored to the requirements of RT-phantom technology, is presented. The PKM consists of low cost standardized mechanical components and sets the target structures, which are located inside a human-equivalent area, into translational and rotational motion in three degrees-of-freedom (DOFs). Only a part of the end-effector is located within the human-equivalent area. All the remaining parts of the PKM are located outside that area. Two versions of the manipulator are presented in detail: their kinematics are derived and their kinetostatic properties are compared. This includes a workspace analysis and the analysis of the transmission behavior in general, meaning the influence of the most important design parameters on the performance. It can be shown that practical differences of both kinematics are negligible, while the modified version provides significant mechanical advantages. In conclusion, a first special purpose manipulator for application in the evolving field of RT-phantom technology is presented. The PKM, which employs a novel kinematic structure, provides higher suitability for its purpose than any other robotic system employed so far for the same purpose.
Mobility and Constraint Analysis of Interconnected Hybrid Flexure Systems Via Screw Algebra and Graph Theory
Authors: Sun Frederick , Hopkins Jonathan B.
Published: February 2017

This paper introduces a general method for analyzing flexure systems of any configuration, including those that cannot be broken into parallel and serial subsystems. Such flexure systems are called interconnected hybrid flexure systems because they possess limbs with intermediate bodies that are connected by flexure systems or elements. Specifically, the method introduced utilizes screw algebra and graph theory to help designers determine the freedom spaces (i.e., the geometric shapes that represent all the ways a body is permitted to move) for all the bodies joined together by compliant flexure elements within interconnected hybrid flexure systems (i.e., perform mobility analysis of general flexure systems). This method also allows designers to determine (i) whether such systems are under-constrained or not and (ii) whether such systems are over-constrained or exactly constrained (i.e., perform constraint analysis of general flexure systems). Although many flexure-based precision motion stages, compliant mechanisms, and microarchitectured materials possess topologies that are highly interconnected, the theory for performing the mobility and constraint analysis of such interconnected flexure systems using traditional screw theory does not currently exist. The theory introduced here lays the foundation for an automated tool that can rapidly generate the freedom spaces of every rigid body within a general flexure system without having to perform traditional computationally expensive finite element analysis. Case studies are provided to demonstrate the utility of the proposed theory.
Parameters Affecting the Local Buckling Response of High Strength Linepipe
Authors: Fatemi Ali , Kenny Shawn
Published: February 2017

The local buckling response and post-buckling mechanical performance of high strength linepipe subject to combined loading state was evaluated using the finite element (FE) simulator abaqus/standard v6.12. The constitutive model parameters were established through laboratory tests and the numerical modeling procedures were verified with large-scale experiments investigating the local buckling response of high strength linepipe. The numerical predictions demonstrated a high level of consistency and correspondence with the measured experimental behavior with respect to the peak moment, strain capacity, deformation mechanism, and local buckling response well into the postyield range. A parametric study on the local buckling response of high strength plain and girth weld pipelines was conducted. The loading conditions included internal pressure and end rotation. The pipe mechanical response parameters examined included moment–curvature, ovalization, local strain, and modal response. The magnitude and distribution of the characteristic geometric imperfections and the end constraint, associated with the boundary conditions and pipe length, had a significant influence on the predicted local buckling response. The importance of material parameters on the local buckling response, including the yield strength (YS), yield strength to tensile strength ratio (Y/T), and anisotropy, was also established through the numerical parameter study. For girth weld linepipe, the study demonstrated the importance of the local high/low misalignment, associated with the circumferential girth weld, on the local buckling response.
Active Engine Vibration Control During Start/Stop in a Hybrid Electric Vehicle
Authors: Velazquez Alcantar Jose , Johri Rajit , Kuang Ming
Published: February 2017

Disturbances during engine starts and stops can propagate to the drive wheels with minimal damping in the power split hybrid transaxle due to the system architecture. One such disturbance is the engine cranking torque from pumping & compression during the motoring phase of engine starts and stops before fueling. This paper proposes a control system to compensate for the engine disturbance and reduce the magnitude of the disturbance on the driveline. A high fidelity model of the power split transaxle is developed and validated with test data for NVH analysis. A simple model of a four cylinder engine is developed that can run in real-time and accurately estimate the cranking torque disturbance from the engine. It is show that the engine speed in the power split transaxle is controlled via a generator speed feedback loop. Performing a linear system analysis reveals that the addition of a feedforward term in the loop which is based on the engine cranking torque can reduce the driveline disturbance. It is shown through simulation that the proposed engine model with the feedforward controller can reduce the engine disturbance on the driveline. The engine model and feedforward controller are finally implemented on the production control module of a test vehicle and it is shown that the proposed control strategy can reduce the driveline disturbance by as much a 65% during engine starts. Moreover, it shown that the engine model can run in real-time and correlates well with in-cylinder pressure data measured from the engine.
Formation Maneuvering Control of Nonholonomic Multi-Agent Systems
Authors: Khaledyan M. , de Queiroz M.
Published: February 2017

In this paper, we present a leader-follower type solution to the formation maneuvering problem for multiple, nonholonomic wheeled mobile robots. Our solution is based on the graph that models the coordination among the robots being a spanning tree. Our kinematic control law ensures, in the least squares sense, that the robots globally exponentially acquire a given planar formation while the formation globally exponentially tracks a desired trajectory. The proposed control is demonstrated by numerical simulations of five unicycle vehicles.
Multi-Objective Optimal Control of Under-Actuated Bogie System of High Speed Trains
Authors: Sardahi Yousef , Yao Yuan , Sun Jian-Qiao
Published: February 2017

Feedback controls are important to the improvement of dynamic performance of high-speed trains. However, designing an active control for these vehicles is a very challenging task because the control system is usually under-actuated and has to meet multiple conflicting objectives. Examples of conflicting objectives include designing a highly relative stable system while minimizing the control efforts or maximizing the capability of the system to reject external disturbances. In addition, the mathematical models of these systems are not completely controllable and observable. This paper studies multi-objective optimal design of feedback controls for a sub-system of high-speed trains, i.e. the bogie system.

The bogie system can be decomposed such that the observable and controllable components of the model are used to stabilize the internal states and therefore the overall system. A linear mathematical model of the system is used in the design. The controllable and the observable states of the model are separated to form a state-feedback control to drive the internal modes and the whole system to stability. A multi-objective genetic algorithm is used to search for the feedback control gains to optimize three objectives: the Frobenius norm of the control law, relative stability and the disturbance rejection. The solutions of the multi-objective optimization provide various trade-offs among the objectives. Numerical simulations show that the proposed control designs can stabilize the system even at a high critical speed of 500 km/h.
Hierarchical Energy Management Control of Connected Hybrid Electric Vehicles on Urban Roads With Efficiencies Feedback
Authors: Du Zhiyuan , Qiu Lihong , Pisu Pierluigi
Published: February 2017

In this paper, we present a fuel efficient control strategy for a group of connected hybrid electric vehicles (HEVs) in urban road conditions. A hierarchical control architecture is proposed where the higher level controller is located at traffic signal light while the lower level controllers are equipped on each HEV. The higher level controller utilizes Signal Phase and Timing (SPAT) information from the traffic lights to generate target velocities for every HEV, which allows a maximum number of vehicles pass the intersection at given green light window. Model Predictive Control (MPC) is used to track the target velocity and evaluate the energy efficient velocity profile for every vehicle for a given horizon. Each lower level controller then follows the velocity profile (from the higher level controller) in a fuel efficient fashion using adaptive equivalent consumption minimization strategy (A-ECMS). The lower level controller also feeds the average recuperation efficiency in a certain time window back to the higher level controller, thus affects the future velocity profile evaluation from the higher level controller, which is the major contribution of this paper. In this paper, the HEV model is developed based on Autonomie software and the simulation results show the effectiveness of our proposed approach.
Autonomous Collision Imminent Steering Maneuver in Presence of Surrounding Obstacles
Authors: Jafari Rouhollah , Zeng Shuqing , Moshchuk Nikolai
Published: February 2017

In this paper, a collision avoidance system is proposed to steer away from a leading target vehicle and other surrounding obstacles. A virtual target lane is generated based on an object map resulted from perception module. The virtual target lane is used by a path planning algorithm for an evasive steering maneuver. A geometric method which is computationally fast for real-time implementations is employed. The algorithm is tested in real-time and the simulation results suggest the effectiveness of the system in avoiding collision with not only the leading target vehicle but also other surrounding obstacles.
Non-Autonomous Feedback Control for Area Coverage Problems With Time-Varying Risk
Authors: Miah Suruz , Fallah Mostafa M. H. , Panah Arian Y. , Spinello Davide
Published: February 2017

Motivated by area coverage optimization problems with time varying risk densities, we propose a decentralized control law for a team of autonomous mobile agents in a two dimensional area such that their asymptotic configurations optimize a generalized non-autonomous coverage metric. The generalized non-autonomous coverage metric explicitly depends on a nonuniform time-varying measurable scalar field that is not directly controllable by agents. Several interesting scenarios emerge with time varying risk density. In this work, we consider the case of area surveillance against moving targets or external threats penetrating through the perimeter, and the case of environmental monitoring and intervention with deployment of mobile sensors in areas affected by penetration of substances governed by diffusion mechanisms, as for example oil in a marine environment. In the presence of time-varying risk density the coverage metric is non-autonomous as it includes a time varying component that does not depend on the evolution of the agents. Our non-autonomous feedback law accounts for the time-varying component through a term that vanishes when the risk eventually stops evolving. Optimality with respect to the induced non-autonomous coverage is proven in the framework of Barbalat’s lemma, and the performance is illustrated through simulation of the these two scenarios.
Dynamic Optimization of Diesel Air-Path Control for Reduced Pumping Work
Authors: Brewbaker Thomas A. , van Nieuwstadt Michiel
Published: February 2017

One potential method to reduce fuel consumption in diesel engines with variable geometry turbines (VGT) and exhaust gas recirculation (EGR) is to reduce the transient engine pumping work through improved EGR-VGT control. Numerical dynamic programming is applied to investigate optimal EGR-VGT control policies for reduced pumping work on a three-state model of a 6.7-liter medium-duty diesel engine. Optimality is defined by a multi-objective cost function that penalizes pumping work, EGR rate control error, and boost pressure control error. Multiple dynamic programs, each with a different set of cost function weights, are performed over an acceleration in the Heavy-Duty Federal Test Procedure cycle to generate the optimal trade-off between the stated objectives. Additionally, a production-representative EGR-VGT controller is simulated, and the resulting suboptimal performance is compared to the optimal frontier to establish the potential fuel consumption benefit of improved EGR-VGT control.
Actuator Design and Whole-Body Dynamics of Micro Centipede Robots
Authors: Sheynkman David , Wang Cong , Lawhorn Raheem , Lu Lu
Published: February 2017

Micro robots have been recognized as a promising solution for exploring complex and dangerous environments during rescue and reconnaissance missions. The idea of micro centipede robots is drawing increasing attention because of their great potentials to get through rubble and reaching buried areas. This paper explores the possibility of using micro electromagnetic actuators on micro centipede robots, which could give better mobility than using piezoelectric actuators. This paper also discusses the whole-body dynamics of centipede robots. A series of simulation studies are conducted to draw conclusions on how the propulsion characteristics of individual legs and the ground friction affect the dynamics and stability of the whole centipede robot.
Mechatronics-Based Analysis of a 4x4 Vehicle Lateral Dynamics With Passive and Active Drivelines
Authors: Vantsevich Vladimir V. , Paldan Jesse R.
Published: February 2017

This paper presents a mechatronic modeling analysis of a 4×4 hybrid-electric vehicle (HEV) which uses an active driveline system connected to the hybrid powertrain. This active driveline uses a power-splitting device, named a Hybrid-Electric Power-Transmitting Unit (HE-PTU) to control the power split between the front and rear axles. The mathematical model of the active driveline along with two passive drivelines demonstrates the coupling of driveline-steering-system influenced lateral dynamics of the vehicle. Thus, a more flexible, active driveline is able to effectively decouple the driveline and steering systems by producing a compensating torque that influences the tire lateral forces and thus vehicle lateral dynamics. Because of the multiple domains involved in modeling the HE-PTU, a mechatronics-based modeling solution is required to demonstrate the advantage of the active driveline. The mechatronics-based simulation results show how use of the active driveline with a hybrid-electric power transmitting unit can improve the vehicle’s turnability and stability characteristics.
An Experimental Study of Bi-Directional Structure Vibration Suppression Using LPC Impact Dampers
Authors: Gharib Mohamed , Karkoub Mansour
Published: February 2017

Vibration control of large structures has been the focus of a lot of research in recent years. Some of these structures include high rise buildings, offshore platforms, and bridges. In this article, we present the results of an experimental investigation of the usage of linear impact dampers in the control of the elasto-dynamic vibrations of 3D structures. Linear Particle Chain Impact Dampers (LPCIDs) are the off-spring of the commonly used conventional (single unit) impact damper. The free vibration response of a 3D symmetric frame subjected to a bidirectional initial condition is measured and analyzed. The objective is to examine the efficacy of the LPCID in attenuating the free vibrations of 3D frame structures. The settling times and amplitudes of vibration of the structure, with and without the LPCIDs, under free vibration conditions are measured and analyzed to study the efficacy of the dampers. The experimental study showed that the LPCID can be more effective in reducing the structure’s vibration when placed in specific orientations on the structure. Therefore, it can by concluded from the experiments’ outcomes that LPCIDs may be used to effectively attenuate the free vibrations of 3D structures.
A ROS-Simulink Real-Time Communication Bridge Using UDP With a Driver-in-the-Loop Application
Authors: Wahba Mohamed , Leary Robert , Ochoa-Lleras Nicolás , Safi Jariullah , Brennan Sean
Published: February 2017

This paper presents implementation details and performance metrics for software developed to connect the Robot Operating System (ROS) with Simulink Real-Time (SLRT). The communication takes place through the User Datagram Protocol (UDP) which allows for fast transmission of large amounts of data between the two systems. We use SLRT’s built-in UDP communication and binary packing blocks to send and receive the data over a network. We use implementation metrics from several examples to illustrate the effectiveness and drawbacks of this bridge in a real-time environment. The time latency of the bridge is analyzed by performing loop-back tests and obtaining the statistics of the time delay. A proof of concept experiment is presented that utilizes two laboratories that ran a driver-in-the-loop system despite a large physical separation. This work provides recommendations for implementing data integrity measures as well as the potential to use the system with other applications that demand high speed real-time communication.
Robust Active Imbalance Rejection for Active Magnetic Bearing-Rotor Systems
Authors: Yunt Kerim
Published: February 2017

In this work a robust current control strategy is developed in order to counteract the imbalance forces of a rotor which is levitated by an active magnetic bearing (AMB) system. A model-based and physics based design procedure for active imbalance rejection is presented, which solely derives from the configuration of a given AMB system such as physical parameters, rotational speed and controller capacity. An output feedback controller is developed which eliminates the synchronous vibrations by applying synchronous forces at the AMB force locations. The controller is developed by making use of the sliding mode control (SMC) formalism. Within the boundary layer the controller is equivalent to a MIMO proportional-derivative (PD) controller with an output reference trajectory. The active vibration suppression forces are obtained as a control rule, which implement the tracking of a reference trajectory in the output space. The time-varying reference trajectory is obtained as the particular solution of a first-order linear ODE with periodic forcing function, where the periodic forcing function is the generalized synchronous imbalance excitation forces. For a given AMB system and known unbalance, the achievable rotational speeds such that the AMB system can be operated, are derived. Within the boundary layer, which is the main operation range, the MIMO PD controller is parameterized by the rotational speed.
System Level Performance and Reliability Investigation of Hydraulic Circuits Using Physics Based Models
Authors: Mutlu Mete , Franchek Matthew A. , Gutierrez Jose A. , Pereira Luis R.
Published: February 2017

Hydraulic circuits have been employed by automotive, aerospace, oil & gas and mining industries for an extended amount of time. During the design stage of the hydraulic circuits, the system level dynamic interactions between components need to be analyzed to enhance system performance and reliability. Physics based, low dimensional modeling and simulation is proposed to help system level design and to verify proper operation of hydraulic components. Presented in this paper is physics based modeling process of a hydraulic circuit. Low dimensional model of the hydraulic circuit is used to investigate dynamic interactions between components on MATLAB-Simscape® platform. The existence of hydraulic oscillations due to aging regulator seals is simulated and a method to reduce these oscillations is presented. It is also shown that the inadequate source to supply pilot pressure to hydraulically piloted valves can create similar hydraulic oscillations and reduce system reliability and remaining operational life.
Dynamics Modeling of Train-Track-Harvester System and In-Field Testing of Railroad Energy Harvester
Authors: Lin Teng , Pan Yu , Zuo Lei
Published: February 2017

An electromagnetic energy harvester for railroad application featuring anchorless mounting is presented along with system modeling and in-field testing results. The spring-reset mechanism allows harvester to be installed on any railroad sleepers without any change to the existing ballast and foundation. A railway train-track-harvester model is established for design validation and risk assessment. Within harvester, train-pass induced track vibration is translated to rotation and then conditioned thru mechanical motion rectifier mechanism for generator to operate in one direction with a relatively steady speed. Particularly, in-field test demonstrates that harvester can harness electric at an average power of 6.9 Watts and a peak power of 60 Watts when test cargo train running at 40 mph (64 km/h). Dynamic modeling of the vehicle-rail system are also developed to estimate the displacement of the sleeper under various train weight and speed. Simulation result based on typical train parameters are provided and compared with infield test result.
Handling Model and Implementation Uncertainties via an Adaptive Discrete Sliding Mode Controller Design
Authors: Amini Mohammad Reza , Shahbakhti Mahdi , Pan Selina , Hedrick J. Karl
Published: February 2017

Analog-to-digital conversion (ADC) and uncertainties in modeling the plant dynamics are the main sources of imprecisions in the design cycle of model-based controllers. These implementation and model uncertainties should be addressed in the early stages of the controller design, otherwise they could lead to failure in the controller performance and consequently increase the time and cost required for completing the controller verification and validation (V&V) with more iterative loops. In this paper, a new control approach is developed based on a nonlinear discrete sliding mode controller (DSMC) formulation to mitigate the ADC imprecisions and model uncertainties. To this end, a DSMC design is developed against implementation imprecisions by incorporating the knowledge of ADC uncertainties on control inputs via an online uncertainty prediction and propagation mechanism. Next, a generic online adaptive law will be derived to compensate for the impact of an unknown parameter in the controller equations that is assumed to represent the model uncertainty. The final proposed controller is an integrated adaptive DSMC with robustness to implementation and model uncertainties that includes (i) an online ADC uncertainty mechanism, and (ii) an online adaptation law. The proposed adaptive control approach is evaluated on a nonlinear automotive engine control problem in real-time using a processor-in-the-loop (PIL) setup with an actual electronic control unit (ECU). The results reveal that the proposed adaptive control technique removes the uncertainty in the model fast, and significantly improves the robustness of the controllers to ADC imprecisions. This provides up to 60% improvement in the performance of the controller under implementation and model uncertainties compared to a baseline DSMC, in which there are no incorporated ADC imprecisions.
Statistical Quantification of Least-Squares Battery State of Charge Estimation Errors
Authors: Mendoza Sergio , Liu Ji , Mishra Partha , Fathy Hosam K.
Published: February 2017

This paper derives analytic expressions for both the mean and variance of battery state of charge (SOC) estimation error, assuming a least squares estimation law. The paper examines three sources of estimation error, namely: (i) voltage measurement errors (both bias and noise), (ii) current measurement bias, and (iii) mismatch between the order of the battery model used for estimation and the true order of the battery’s dynamics. There is already a rich literature on quantifying battery SOC estimation errors for different estimator designs. The novelty of this paper stems from its extensive examination of both the expected SOC estimation bias and noise, for a least squares estimation algorithm, in the presence of three different fundamental sources of these estimation errors. We show, both analytically and using Monte Carlo simulation, that under reasonable operating conditions, the expected bias in SOC estimation for lithium-ion batteries is dominant compared to the expected estimation variance. This leads to the important insight that quantifying SOC estimation variance using Fisher information furnishes overly optimistic predictions of achievable SOC estimation accuracy.
Control of Human Immunodeficiency Virus (HIV) Dynamics With Parameter Uncertainties
Authors: Karagiannis Dimitri , Radisavljevic-Gajic Verica , Ashrafiuon Hashem
Published: February 2017

This work considers a 3-state nonlinear model with two inputs for the controlled dynamics of the human immunodeficiency virus (HIV). The three states represent the number of healthy and unhealthy T-cells as well as the number of free virus particles in a person’s body. The two inputs represent two different types of anti-retroviral drugs that are available to treat a person infected with the virus. These inputs can be used to create a stable nominal point that is much healthier for the patient than the open-loop stable equilibrium point. The goal of this paper is to use the inputs, which are subject to constraints, to efficiently and accurately reach the desired nominal point despite parameter uncertainties. We have designed an integral sliding mode control law to achieve this goal, and simulations are presented to demonstrate the performance of the controller.
Event-Triggering in Three-Dimensional Leader-Follower Formation Control for Unmanned Aerial Vehicles
Authors: Sun Liang , Hu Bin
Published: February 2017

This paper addresses a three-dimensional (3D) leader-follower formation control problem where an event-triggered transmission scheme is developed to schedule the information exchange between the leader and follower unmanned aerial vehicles (UAVs). A novel 3D model based on a local level spherical frame is developed to characterize the relative dynamics of the leader and follower UAVs. Based on this 3D model, a novel non-linear tracking control law is developed to achieve an exponential tracking performance of the system. An event-triggered communication scheduling scheme is adopted under the proposed 3D leader-follower framework in order to achieve an efficient use of communication bandwidth by adapting the transmission time for the changes on UAV states. The stability of the formation control law and the efficiency of the event-triggered method are verified and demonstrated in simulation.
Minimization of Hydrodynamic Power Losses in Oscillating Submerged Structures by a Novel Shape-Morphing Strategy
Authors: Ahsan Syed N. , Aureli Matteo
Published: February 2017

In this paper, we investigate the two dimensional fluid-structure interaction problem of the oscillation of a shape-morphing plate in a quiescent, Newtonian, viscous fluid. The plate is considered as a moving wall for the fluid undergoing two concurrent periodic motions: a rigid oscillation along its transverse direction coupled to a shape-morphing deformation to an arc of a circle with prescribed maximum curvature. Differently from studies concerned with passive flexible structures, here, we introduce the prescribed deformation to specifically manipulate vortex-shedding and modulate hydrodynamic forces and energy losses during underwater oscillations. Computational fluid dynamics simulations are performed to evaluate the effect of the prescribed deformation strategy on the added mass and damping effect along with the hydrodynamic power dissipation. We observe that a minimum in the hydrodynamic power dissipation exists for an optimum curvature of the plate. This finding may allow significant power expenditure reduction in underwater vibrating systems where minimization of energy losses or maximization of quality factor are desirable.
Parameter-Varying Loop-Shaping for Delayed Air-Fuel Ratio Control in Lean-Burn SI Engines
Authors: Tasoujian Shahin , Ebrahimi Behrouz , Grigoriadis Karolos , Franchek Matthew
Published: February 2017

Dynamic systems with time-varying delay in the control input are studied in the present paper. The delay is considered as a varying parameter and Padé approximation is applied to transfer the infinite-dimensional delay problem into a finite-dimensional paradigm represented in the form of a non-minimum phase system (NMP). Inherited delay characteristics are now represented through unstable internal dynamics for the NMP system, which poses restrictions on the achievable control bandwidth thereby resulting in an imperfect tracking performance and poor stability condition. Presented in this paper, is a methodical parameter-varying loop-shaping control design approach, which simultaneously satisfy a variety of control requirements and offer an insight into the limitations posed by the NMP representation. The suggested method is then applied to fueling control in lean-burn gasoline engines addressing the varying transport and combustion delay. The developed approach is validated with experimental data on a Ford F-150 truck SI lean-burn engine with large time-varying delay in the control loop and the closed-loop system responses are presented to demonstrate disturbance rejection, measurement noise attenuation, and robustness properties against delay estimation errors.
Design Considerations for Waste Energy Recovery With Electric Turbocompounding
Authors: Salehi Rasoul , Kiwan Rani , Martz Jason , Stefanopoulou Anna G.
Published: February 2017

This paper studies the use of an electric turbogenerator (ETG) for waste energy recovery from the exhaust gas of a 13 L Heavy Duty Diesel (HDD) engine. Up to 1% brake specific fuel consumption (BSFC) reduction is predicted for this system at high engine loads using a validated mean value engine model. However, the addition of the ETG reduces the air-fuel equivalence ratio (λ) and increases exhaust gas recirculation (EGR) rate by 10%, deteriorating the engine-out smoke emissions. This challenge is addressed by decreasing the EGR valve position and the asymmetry in the twin scroll turbine. With these modifications, the predicted high load BSFC reduction is 2% and the EGR and λ approach their original values.

The HDD engine is then tested experimentally with the ETG emulated by a valve downstream of the main turbocharger. The experimental results confirm the simulation predictions with the stock engine calibration and geometry, where EGR valve sweeps show the potential of this actuator for remedying the detrimental ETG backpressure effects, which ultimately improves the combined engine and ETG BSFC by 0.6% at high loads. Combining the simulated turbo sizing and the experimental EGR valve results indicates that up to 1.6% BSFC reductions are possible for the HDD engine with an integrated ETG, without deteriorating emission levels. Finally, simulations show that during a torque step the ETG should be bypassed to avoid deterioration in the dynamic response of the engine.
Sensor Fault Diagnosis of Connected Vehicles Under Imperfect Communication Network
Authors: Abdollahi Biron Zoleikha , Dey Satadru , Pisu Pierluigi
Published: February 2017

Connected vehicles are one of the promising technologies for future Intelligent Transportation Systems (ITS). Despite being the potentially beneficial in creating an efficient, sustainable and green transportation system, connected vehicles presents a set of specific challenges from safety and reliability standpoint. The first challenge arises from the information lost due to unreliable communication network which affects the control/management system of the individual vehicles and the overall system. Secondly, faulty sensors can affect the individual vehicle’s safe operation and in turn will create a potentially unsafe node in the vehicular network. Therefore, it is of utmost importance to take these issues into consideration while designing the control/management algorithms of the individual vehicles as a part of connected vehicle system. In this paper, we consider a connected vehicle system under Co-operative Adaptive Cruise Control (CACC) and propose a diagnostic scheme that deals with these aforementioned challenges. The effectiveness of the overall diagnostic scheme is verified via simulation studies.
Determining Minimum and Maximum Number of Agents Required for Planar Cable-Suspended Aerial Manipulation
Authors: Hung Henry , Sood Niteesh , Sreenath Koushil
Published: February 2017

This paper proposes a method for optimal selection of number of agents in a cooperative multi-agent system for dynamic aerial transportation of a cable-suspended load along a desired trajectory. We consider the system of n planar quadrotors with a cable suspended load, show that this system is differentially flat, and study the effect of varying the number of quadrotors, load and quadrotor masses, on the maximum velocity of the load trajectory and minimum thrust required. We determine the minimum (maximum) number of agents required for traversing a load trajectory for various values of the load mass.
A Numerical Study of Information Entropy in EEG Wavelet Analysis
Authors: Ghorbanian Parham , Ashrafiuon Hashem
Published: February 2017

The purpose of this study is to numerically evaluate the performance of information entropy in electroencephalography (EEG) signal analysis. In particular, we use EEG data from an Alzheimer’s disease (AD) pilot study and apply several wavelet functions to determine the signals’ time and frequency characteristics. The wavelet entropy and wavelet sample entropy of the continuous wavelet transformed data are then determined at various scale ranges corresponding to major brain frequency bands. Non-parametric statistical analysis is then used to compare the entropy features of the EEG data obtained in trials with AD patients and age-matched healthy normal subjects under resting eyes-closed (EC) and eye-open (EO) conditions. The effectiveness and reliability of both choice of wavelet functions and the parameters used in wavelet sample entropy calculations are discussed and the ideal choices are identified. The result shows that, when applied to wavelet transformed filtered data, information entropy can be effective in determining EEG discriminant features, after selecting the best wavelet functions and window size of the sample entropy.
On Aerial Indoor Position Control and System Integration for Quadcopters Using Lidars and Inertial Measurement Units
Authors: Zimmerman Nathan , Carey Kellen , Ababei Cristinel
Published: February 2017

The main contribution of this paper is to introduce a computationally efficient iterative closest line (ICL) algorithm for determining indoor position drift of a quadcopter using minimal lidar data. In addition, we present the system-level design and implementation of a new quadcopter both as hardware and flight control algorithms. Such a platform allows us to develop and experiment new control and system optimization techniques. As an example, we discuss how the proposed ICL algorithm is used for position hold and control purposes by plugging it into the low level implementation of the flight control algorithm of the quadcopter. For testing and validation we use simulations with real world data. As part of the system-level design aspects, we present an investigation of the quadcopter power consumption. We are interested in power consumption because it is the major factor that determines the flight time of a typical quadcopter. We believe that this work is a contribution toward achieving better quadcopter design and control for indoor autonomous navigation.
Wearable Sleepiness Detection Based on Characterization of Physiological Dynamics
Authors: Ma Zheren , Li Brandon C. , Yan Zeyu , Chen Dongmei , Li Wei
Published: February 2017

Sleepiness has been considered as one of the major contributors to driver error that causes many automobile accidents. Among various technologies developed to address this issue, the electrooculography (EOG) signal is considered most suitable for sleepiness detection. It is simple, and resilient to environmental factors such as light intensity and driver movement. Most importantly, the physiological signal changes in an early stage and can be used to detect the on-set of human sleepiness. In this paper, we introduce the development of a wearable sleepiness detection system based on analyzing EOG signal dynamics. The system includes wearable sensors, amplifying and transmitting circuits, and a smart phone that could alarm the driver if sleepiness is detected. In this system, the EOG signal is considered as a neurophysiological response of the oculomotor system. Blink signatures are extracted from the EOG signal. It was found that the poles of a linearized blinking motion associated with an alert state are different from those associated with a sleepy state. Based on this understanding, an algorithm to detect the driver’s sleepiness was developed. A proof of concept device design has been completed. This system will help a driver to correct the behavior, and ultimately saves lives.