bluuebunny/crossref_metadata_2025 huggingface dataset:
Ghost Structures, Pasting, Rheological and Textural Properties between Mesona Blumes Gum and Various Starches
Authors: Feng Tao , Su Qiang , Zhuang Haining , Ye Ran , Gu Zhengbiao , Jin Zhengyu
Published: March 2014

In this study, the ghost structures of potato starch granule gelatinization in the presence and absence of Mesona Blumes gum (MBG) at different temperatures and time points were studied. Our results indicated that ghost structures could form merely after the amylose was completely leached from granules. In addition, MBG could prevent amylose from leaching outside the granules, and thus extend ghost structure existence in aqueous solution. Furthermore, the interactions among eight kinds of starches and MBG were assessed by Brabender parameters. It was concluded that rice, wheat, pea and corn starches could be significantly influenced by MBG (P < 0.05), then followed by mung bean and sweet potato starch, whereas the effects of tapioca and potato starch could be insignificant (P > 0.05). Textural measurement illustrated that MBG/rice starch gel was the hardest among all samples in this study. Rheological properties of rice starch and various hydrocolloids were evaluated at 25C by frequency sweep from 1 to 10 Hz with a constant strain 1%. It was shown that rice starch and MBG could also form the strongest gel.

Practical Applications

To understand the interaction between MBG and different starches from various sources, ghost structures, Brabender curves, and textural and rheological properties were investigated in this paper. Ghost structure indicated that gels between MBG and starch might be constituted by collapsed starch granule, MBG and swollen amylose. Brabender curves showed that MBG could affect rice starch gelatinization significantly (P < 0.05). Moreover, the results of textural studies also demonstrated that MBG/rice starch gels formed the hardest gel. In addition, the results obtained from rheological properties between various hydrocolloids and rice starch suggested that the strongest MBG/rice starch gel occurred. Therefore, gels formed by MBG and rice starch might be potentially used as a novel filler or thickener in food industry.
The Devil Rejoiced: Volk, Devils and Moral Panic in White South Africa, 1978–1982
Authors: Dunbar Danielle , Swart Sandra
Published: March 2014

The first four years of P.W. Botha's premiership in apartheid South Africa were plagued by intra‐party politicking, renewed anti‐apartheid resistance, economic instability, and Satan. Between 1978 and 1982, the heavy political rhetoric of “total onslaught” inflected perceived “moral onslaught” in a virulent moral panic over Satanism in white, and particularly Afrikaner, South Africa. With attention to its discursive and socio‐political context, this paper seeks to explore the emergence of this distinct satanic moral panic in white South African history, arguing that it reflects the intense political and moral ambiguity of white society as the edifices of apartheid began to fracture.
Effect of Ceramic Thickness and Shade on Mechanical Properties of a Resin Luting Agent
Authors: Passos Sheila Pestana , Kimpara Estevão Tomomitsu , Bottino Marco Antonio , Rizkalla Amin S. , Santos Gildo Coelho
Published: March 2014

Purpose

This study aimed to investigate the influence of ceramic thickness and shade on the Knoop hardness and dynamic elastic modulus of a dual‐cured resin cement.

Materials and Methods

Six ceramic shades (Bleaching, A1, A2, A3, A3.5, B3) and two ceramic thicknesses (1 mm, 3 mm) were evaluated. Disk specimens (diameter: 7 mm; thickness: 2 mm) of the resin cement were light cured under a ceramic block. Light‐cured specimens without the ceramic block at distances of 1 and 3 mm were also produced. The Knoop hardness number (KHN), density, and dynamic Young's moduli were determined. Statistical analysis was conducted using ANOVA and a Tukey B rank order test (p = 0.05).

Results

The bleaching 1‐mm‐thick group exhibited significantly higher dynamic Young's modulus. Lower dynamic Young's moduli were observed for the 3‐mm‐thick ceramic groups compared to bleaching 3‐mm‐thick group, and no difference was found among the other 3‐mm groups. For the KHN, when A3.5 3‐mm‐thick was used, the KHN was significantly lower than bleaching and A1 1‐mm‐thick ceramic; however, no difference was exhibited between the thicknesses of the same shade.

Conclusions

The dual‐cured resin cement studied irradiated through the 1‐mm‐thick ceramic with the lightest shade (bleaching ceramic) exhibited a better elastic modulus, and there was no effect in KHN of the resin cement when light cured under different ceramic shades and thicknesses (1 and 3 mm), except when the A3.5 3‐mm‐thick ceramic was used.

Clinical Significance

Variolink II irradiated through ceramic with the lowest chroma exhibited the highest elastic modulus; therefore, the light activation method might not be the same for all clinical situations.
Globalizing Indigenous Psychology: An East Asian Form of Hierarchical Relationalism with Worldwide Implications
Authors: Liu James
Published: March 2014

Globalization has changed almost every facet of life for people around the world, and today the flow of influence is no longer uni‐directional. It is argued that East Asian (and especially Chinese) societies are anchored in an indigenous form of hierarchical relationalism where social structure is produced by relational obligations of an ethical and normative nature that have slowed its traditional culture “melting into air” as prophesied by Marx. The successfully modernization of East Asia has involved hybridization, compartmentalization, and sequencing of traditional psychological features of Confucianist societies such as delay of gratification and respect for education, paternalistic leadership, filial piety, and beliefs in harmony or benevolence. Features of hierarchical relationalism are adaptable to creating niches for East Asian societies that thrive under globalization as characterized by the paradoxical coupling of economic inequality in fact with discourses of equality in principle. Moral, ethical demands for enlightened leadership constrain East Asian elites to at least attempt to protect subordinates and protect societal (rather than merely individual or familial) well‐being. A fundamental contribution of East Asia to global society may be in the articulation of how to ameliorate economic inequality using Confucian principles of hierarchical relationalism.
Topical N‐Acetylcysteine for the Treatment of Lamellar Ichthyosis: An Improved Formula
Authors: Davila‐Seijo Paula , Flórez Angeles , Davila‐Pousa Carmen , No Nuria , Ferreira Carlos , De la Torre Carlos
Published: March 2014

Topical N‐acetylcysteine is gaining recognition as a useful and safe therapy for lamellar ichthyosis. We report a case of inherited lamellar ichthyosis that showed a good response to treatment with a new formula of N‐acetylcysteine cream. With this new formula, which is described in the article in a practical manner, the odor of sulfur was minimized and we obtained excellent adherence to treatment.
Effects of focal prefrontal cortex lesions on electrophysiological indices of executive attention and action control
Authors: Solbakk Anne‐Kristin , Løvstad Marianne
Published: March 2014

The human capacity to maintain an overarching control over mental states and behavior relies on multiple, distributed and dynamically interacting brain networks, in which prefrontal cortex (PFC) plays a critical role. PFC exerts top‐down executive control over subcortical and posterior cortical areas via extensive reciprocal connections. The orbital, lateral, and medial PFC subdivisions are associated with distinct executive functions, but their precise roles in large‐scale neural networks remain to be determined. The main objective of our research program is to specify cognitive and neural mechanisms that govern executive control functions. We study effects of focal PFC lesions on behavioral and electrophysiological correlates of attention and action control utilizing experiments that relate to real‐life requirements for executive control. We provide a selective review of studies on the impact of lesions to PFC subregions on novelty processing, anticipatory attention, and action preparation and motor inhibition. The studies provide evidence for the contribution of both lateral, dorsomedial and orbital PFC in novelty processing and dynamic contextual updating. We also report evidence for a role of lateral PFC in motor preparation and anticipatory attention. In contrast to the common view that orbitofrontal cortex plays a general role in inhibitory control, we report findings indicating an involvement in action outcome monitoring rather than in behavioral inhibition as such. We argue that improved understanding of how basic aspects of attentional control and inhibition is regulated in the brain, will shed light on the complex behavioral, cognitive and emotional problems experienced by patients with executive dysfunction.
Adam Smith on Monopoly Theory. Making good a lacuna
Authors: Salvadori Neri , Signorino Rodolfo
Published: March 2014

This article analyses Adam Smith's views on monopoly by focusing on Book IV and V of The Wealth of Nations. It argues that the majority of scholars have assessed Smith's analysis of monopoly starting from premises different from those, actually though implicitly, used by Smith. We show that Smith makes use of the word ‘monopoly’ to refer to a heterogeneous collection of market outcomes, besides that of a single seller market, and that Smith's account of monopolists' behaviour is richer than that provided by later theorists. We also show that Smith was aware of the growth‐retarding effect of monopoly and urged State regulation.
Separation of centrifuged whole blood and pooled buffy coats using the new CompoMat G5: 3 years experience
Authors: Bontekoe I. J. , van der Meer P. F. , Mast G. , de Korte D.
Published: March 2014

Background and Objectives

Semi‐automatic separation devices can be used for the separation of centrifuged whole blood into leucoreduced red cell concentrate (LR‐RCC), plasma and buffy coat (BC) and to make platelet concentrates (PC) from pooled BCs. To improve and to obtain a more uniform and standardized process, the CompoMat G5 (Fresenius) was implemented, a new‐generation semi‐automated device.

Materials and Methods

Uniform programs for WB separation and preparation of PCs were validated, using collection and pooling systems with CompoFlow (CF) closures, which can be automatically opened by the G5. Cell counts were performed and compared with historic data of blood components obtained with the formerly used Compomat G4 and Optipress II. After implementation, different adjustments were made to improve product quality.

Results

Leucoreduced red cell concentrates (280 ± 15 ml, 53 ± 5 g haemoglobin) and plasma (317 ± 16 ml) met European guidelines. BCs (48 ± 2 ml, 0·42 ± 0·05 l/l, 93 ± 25 × 109 platelets) contained a similar platelet (PLT) content as BC prepared before with the Compomat G4. A relatively high percentage (4–6%) of PCs (330 ± 17 ml, 330 ± 50 × 109 PLT, 0·12 ± 0·21 × 106 leucocytes) contained <250 × 109 PLT which was the subject of improvement studies. After implementation, RCC and BC discard decreased and workload was less. Operator complaints were also less frequent.

Conclusion

The same high‐quality blood components can be prepared by using the CompoMat G5 as previously with other semi‐automated devices. Improvement was realized by automation of the opening process by the use of collection systems with CF closures, which led to a decrease in discarded units and workload.
Market Simulation Based Sensitivity Analysis as a Means to Inform Design Effort as Applied to Photovoltaic Panels
Authors: Frischknecht Bart D. , Whitefoot Kate S.
Published: March 2014

Product design success depends on the engineering performance of the product and also on the reaction of external stakeholders such as customers, retailers, and policymakers. This article illustrates how an early-stage engineering design performance model can be incorporated into a decision framework representing customers, retailers, and policymakers to assess the revenue potential for different technologies. Sensitivity analysis is performed for revenue and other stakeholder decision criteria with respect to the design performance measures. We illustrate our approach for photovoltaic panels in the context of the residential solar electricity generation system market in New South Wales, Australia that experienced a variety of federal and state government incentive programs between 2010 and 2012. The analysis is based on engineering performance modeling, discrete choice demand modeling, and cost modeling all with simplifying assumptions.
Identification of Instabilities in Rotorcraft Systems
Authors: Sonti Siddharth , Horn Joseph , Keller Eric , Ray Asok
Published: March 2014

This short paper presents a data-driven method for identification of stability margin in rotorcraft system dynamics and the underlying concept is built upon the principles of Symbolic Dynamics. The algorithm involves wavelet-packet-based pre-processing to remove spurious disturbances and to improve the signal-to-noise ratio (SNR) of sensor time series. A quantified measure, called Instability Measure, is constructed from the processed time series data to obtain an estimate of the relative instability of the dynamic modes of interest on the rotorcraft system. The proposed method has been tested with numerical simulations; and correlations between the Instability Measure and the damping parameters of selected dynamic modes of the rotor blade have been established.
Fast, High-Fidelity Simulation of Dynamic Thermo-Fluid States in Refrigeration Systems
Authors: Wait Keith W. , Kempiak Michael , Abbasi Bahman
Published: March 2014

A dynamic model of a heat exchanger containing a phase-changing refrigerant is presented. Due to fundamental characteristics of phase-changing fluids, the model is computationally inefficient. Remedies to this inefficiency, such as hastened computation of fluid properties, realistic heat transfer coefficient blending, and active control of oscillations in the thermodynamic state of the system are presented. These remedies are shown to minimally impact the output of the model while allowing it to execute much more quickly than real-time.
Energy-Conserving Gaits for Point-Foot Planar Bipeds: A Five-DOF Case Study
Authors: Jafari Rouhollah , Flynn Louis L. , Hellum Aren , Mukherjee Ranjan
Published: March 2014

We propose a general method for designing energy-conserving gaits for point-foot planar bipeds. The method relies on satisfying specific boundary conditions for joint trajectories of the biped. These boundary conditions ensure that potential and kinetic energies of the biped are the same at the beginning and end of each step and there is no impact, i.e, no energy loss, at the time of swing-foot touchdown. The mechanical energy required by the gait over each step is therefore zero from the principle of work and energy. To illustrate the procedure for designing energy-conserving gaits, the proposed method is applied to a general five-dof biped.
Derivatives and Parameter Designs of Arbitrary Cross-Section Inhomogenous Beams’ Modes
Authors: Xing J. W. , Zheng G. T.
Published: March 2014

As highly sensitive to structural parameter variations, it is necessary to study relations between derivatives of displacement modes and structural design parameters. This paper proposes an integral technique for obtaining the analytical solutions of slope and curvature modes of arbitrary cross-section inhomogeneous cantilever beam. The method is validated by comparing the computation results of modal frequencies and shapes with both numerical and analytical solutions. Furthermore, based on the presented method, we have established explicit expressions for the structural parameters sensitivity of the slope/curvature mode shapes. An example of parameter design is also presented for a cantilever beam with the proposed sensitivity analysis method.
Nonlinear Clutch Engagement Control
Authors: Chen Jyh-Shin , Zhu Yongjie
Published: March 2014

Clutches are widely used in transmissions of hybrid electric and conventional vehicles. Smooth clutch engagement is a prerequisite for good drivability. A nonlinear control to smoothly engage a clutch is proposed. The control does not use the clutch torque capacity to control clutch slip. Instead, it regulates the torque applied to the inertia at the clutch input. The control requires very little calibration. Simulation results are presented. Theoretical proofs for stability and robustness are also included.
Hardening and Softening Characteristics of a Piecewise Linear Isolator Under 1G Gravity
Authors: Wang X. , Zheng G. T.
Published: March 2014

The frequency responses of a piecewise isolator mounted on a moving flexible base are investigated. A procedure, which is based on Equivalent Linearization method and transfer function, is proposed to study this two-degrees-of freedom nonlinear system. The influence of 1G gravity on the nonlinearity of the system frequency responses is investigated and presented in detail. It is shown that the piecewise stiffness may demonstrate both hardening and softening properties due to different amplitude, clearance and gravity.
An Experimental Testbed for Multi-Robot Tracking of Manifolds and Coherent Structures in Flows
Authors: Michini Matthew , Mallory Kenneth , Larkin Dennis , Hsieh M. Ani , Forgoston Eric , Yecko Philip A.
Published: March 2014

In this paper, we describe the development of an experimental testbed capable of producing controllable ocean-like flows in a laboratory setting. The objective is to develop a testbed to evaluate multi-robot strategies for tracking manifolds and Lagrangian coherent structures (LCS) in the ocean. Recent theoretical results have shown that LCS coincide with minimum energy and minimum time optimal paths for autonomous vehicles in the ocean. Furthermore, knowledge of these structures enables the prediction and estimation of the underlying fluid dynamics. The testbed is a scaled flow tank capable of generating complex and controlled quasi-2D flow fields that exhibit wind-driven double-gyre flows. Particle image velocimetry (PIV) is used to extract the 2D surface velocities and the data is then processed to verify the existence of manifolds and Lagrangian coherent structures in the flow. The velocity data is then used to evaluate our previously proposed multi-robot LCS tracking strategy in simulation.
Damage Identification in Collocated Structural Systems Using Structural Markov Parameters
Authors: Bighamian Ramin , Mirdamadi Hamid Reza , Hahn Jin-Oh
Published: March 2014

This paper presents a novel approach to damage identification in a class of collocated multi-input multi-output structural systems. In the proposed approach, damage is identified via the structural Markov parameters obtained from a system identification procedure, which is in turn exploited to localize and quantify damage by evaluating relative changes occurring in the mass and stiffness matrices associated with the structural system. To this aim, an explicit relationship between structural Markov parameters versus mass and stiffness matrices is developed. The main strengths of the proposed approach are that it is capable of quantitatively identifying the occurrence of multiple damages associated with both mass and stiffness characteristics in the structural system, and it is computationally efficient in that it is solely based on the structural Markov parameters but does not necessitate costly calculations related to natural frequencies and mode shapes, making it highly attractive for structural damage detection and health monitoring applications. Numerical examples are provided to demonstrate the validity and effectiveness of the proposed approach.
Observer Based Oxygen Fraction Estimation for a Dual-Loop EGR Diesel Engine Fueled With Biodiesel Blends
Authors: Zhao Junfeng , Wang Junmin
Published: March 2014

This paper investigates the influence of biodiesel on the effectiveness of exhaust gas recirculation (EGR) in modern Diesel engines equipped with dual-loop EGR systems. Intake manifold oxygen fraction, which is an important factor for both combustion and emissions, is selected as a new reference for evaluating the equivalent EGR level instead of EGR ratio. A Luenberger-like observer for the oxygen fraction is designed based on the dynamic model of the air-path loop with consideration of the existence of oxygen content in the fuel. The convergence of the observer is proved with the assistance of some physical insight into the engine system. The performance of the observer is validated on a high-fidelity engine model built in GT-Power. The results show that when the same amount of fuel is injected, there is an increase in the exhaust oxygen concentration for biodiesel as oxygen content in fuel increases. Then the higher exhaust oxygen concentration leads to an increase in the intake manifold oxygen fraction, since the engine control unit (ECU) commanded EGR valve angles are constant across different fuels. This real-time oxygen fraction estimation approach is potentially useful for mitigating the biodiesel NO x emission effect.
A Dual-Loop EGR Engine Air-Path Oxygen Concentration Model With Time-Varying Transport Delays
Authors: Zeng Xiangrui , Wang Junmin
Published: March 2014

Dual-loop exhaust gas recirculation (EGR) systems can provide control authorities for adjusting the engine in-cylinder gas conditions. However, the transport delay in the EGR air-path makes some simple oxygen concentration dynamic models perform poorly under the transient operating conditions. In this paper, a dual-loop EGR air-path oxygen concentration model considering the time-varying transport delays is developed and a method to calculate the delay time based on the continuity of gas velocity is presented. Simulation validations using a high-fidelity GT-Power 1-D computational engine model show that the developed model can capture the oxygen concentration dynamics during both steady-state and transient operations.
Prediction of ICU In-Hospital Mortality Using Artificial Neural Networks
Authors: Xia Henian , Keeney Nathan , Daley Brian J. , Petrie Adam , Zhao Xiaopeng
Published: March 2014

This work aims to predict in-hospital mortality in the open-source Physionet ICU database from features extracted from the time series of physiological variables using neural network models and other machine learning techniques. We developed an effective and efficient greedy algorithm for feature selection, reducing the number of potential features from 205 to a best subset of only 47. The average of five trials of 10-fold cross validation shows an accuracy of (86.23±0.14)%, a sensitivity of (50.29±0.22)%, a specificity of (92.01 ± 0.21)%, a positive prediction value of (50.29±0.50)%, a negative prediction value of (92.01±0.00)%, and a Lemeshow score of 119.55±9.87. By calibrating the predicted mortality probability using an optimization approach, we can improve the Lemeshow score to 27.51±4.38. The developed model has the potential for application in ICU machines to improve the quality of care and to evaluate the effect of treatment or drugs.
Unknown Disturbance Estimator Design for Non-Minimum Phase Plants Using Parallel Feed-Forward Model
Authors: Chida Yuichi , Sekiguchi Shota , Kobayashi Hiroyuki , Ikeda Yuichi
Published: March 2014

A novel design method of an unknown disturbance observer for non-minimum phase plants is proposed in the present paper. In order to improve the estimation performance, we introduce the approach as a virtual augmented plant by adding a parallel model to the non-minimum phase real plant. The parallel model is designed so that the virtual augmented model becomes the minimum phase. Thus, it is possible to design the unknown disturbance estimator for the minimum phase plant but for the non-minimum phase plant. As the result, it is possible to improve the estimation performances. In this case, it is important to clarify the relationship between the unknown disturbance estimation signal for the real plant and the virtual augmented plant. In the present paper, the unknown disturbance estimation signal of the real plant is re-constructed by using the disturbance estimation of the virtual plant. And the parallel model design method is also proposed. The effectiveness of the proposed method is verified by numerical simulations for several mechanical vibration systems. The results show that the proposed method can improve estimation performances in comparison with conventional methods.
Robust Sideslip Angle Estimation for Over-Actuated Electric Vehicles: A Linear Parameter Varying System Approach
Authors: Chen Yan , Wang Junmin
Published: March 2014

A new estimation method for estimating the vehicle sideslip angle, mainly based on a linear parameter varying (LPV) model with independently estimated tire friction forces, is proposed for electric ground vehicles (EGVs) with four independent in-wheel motors. By utilizing the individual wheel dynamics, the longitudinal ground friction force is estimated from a PID observer based on a descriptor linear system approach. Moreover, the lateral ground friction force for each wheel is estimated through the friction ellipse relationship given the estimated longitudinal friction force, without relying on explicit tire models. Since the estimation errors of friction forces may bring parameter uncertainty for the LPV system, robust analysis with desired H-infinity performance is given for the observer design of the LPV modeling. This method is specially proposed for large tire slip angles and lateral friction forces. Simulation results for different maneuvers validate this novel sideslip angle estimation method.
Closed-Loop Control of SI-HCCI Mode Switch Using Fuel Injection Timing
Authors: Ravi Nikhil , Jagsch Michael , Oudart Joel , Chaturvedi Nalin , Cook David , Kojic Aleksandar
Published: March 2014

Homogeneous charge compression ignition (HCCI) provides improved efficiency and emissions relative to current engine technologies. One of the barriers to implementing HCCI on production engines is the development of a robust control strategy to transition from traditional spark-ignition (SI) mode to HCCI mode and back. This paper presents such a strategy, based on the control of combustion phasing using fuel injection timing during the mode switch from SI to HCCI. The controller is based on a cycle-by-cycle combustion model developed in previous work. In order to obtain a state estimator for both modes, the model is linearized around operating points corresponding to the steady-states before (SI) and after (HCCI) the switch. The linearized HCCI model is used to synthesize a closed-loop controller to track a desired combustion phasing, with fuel injection timing as the controlled input. The control strategy is tested on a single-cylinder HCCI engine with direct injection. Experimental results at different operating points show that the controller is able to maintain a desirable phasing transient during the mode switch, prevent cycles with very early or late phasing and enable smooth transitions with minimal load fluctuations.
New Results on Continuous-Time Switched Linear Systems With Actuator Saturation
Authors: Duan Chang , Wu Fen
Published: March 2014

This paper further studies the analysis and control problems of continuous-time switched linear systems subject to actuator saturation. Using the norm-bounded differential inclusion (NDI) description of the saturated systems and the minimal switching rule, a set of switched output feedback controllers is designed to minimize the disturbance attenuation level defined by the regional ℒ2 gain over a class of energy-bounded disturbances. The synthesis conditions are expressed as bilinear matrix inequalities (BMIs) and can be solved by numerical search coupled with linear matrix inequality (LMI) optimization. Compared to the previous method based on polytopic differential inclusion (PDI), the proposed approach has good scalability and potentially renders better performance. Numerical examples are provided to verify effectiveness of the proposed approach.
An Ionic-Polymer-Metal-Composite Electrical Model With a Linear Time-Variant Method
Authors: Chang Yi-chu , Kim Won-jong
Published: March 2014

Ionic polymer metal composite (IPMC), categorized as an ionic electroactive polymer (EAP), can exhibit conspicuous deflection with low external voltages (∼5 V). This material has been commonly applied in robotic artificial muscles since reported in 1992 because it can be fabricated in various sizes and shapes. Researchers developed numerous IPMC models according to its deflection in response to the corresponding input stimulation. In this paper, an IPMC strip is modeled (1) as a cantilever beam with a loading distribution on the surface, and (2) with system identification tools, such as an autoregressive with exogenous (ARX)/autoregressive moving average with exogenous (ARMAX) model and an output-error (OE) model. Nevertheless, the loading distribution is non-uniform due to the imperfect surface conductivity. Finally, a novel linear time-variant (LTV) modeling method is introduced and applied to an IPMC electrical model on the basis of the internal environment such as surface resistance, thickness, and water distribution related to the unique working principle of IPMC. A comparison between the simulated and the experimental deflections demonstrates the benefits and accuracy of the LTV electrical model.
Evaluation and Design of Manipulators Based on a Dynamic Accuracy Index Considering Task-Directions
Authors: Kai Yoshihiro
Published: March 2014

Some manipulation tasks have directions of end-effector acceleration of a manipulator and directions for which dynamic accuracy is required in the motion. This paper proposes an index (DAIT: Dynamic Accuracy Index for Task-directions) that allows us to evaluate the dynamic accuracy of manipulators considering the task-directions. Firstly, we derive the DAIT. Secondly, we evaluate some postures of a 2-degrees of freedom (DOF) planar manipulator on the basis of some indices that have been proposed (condition number, dynamic manipulability measure and task compatibility) and the DAIT, respectively. Thirdly, we show a manipulator’s design example based on the DAIT. Finally, from the evaluation and design results, we discuss the usefulness of the DAIT in determining the suitable postures of the manipulator for a given task and in designing the suitable manipulators for a given task.
Acceleration Control of Powered Wheelchairs With Nil-Mode-Exciting Profiler Considering Vibration Characteristic of Human Body
Authors: Takahashi Masaki , Okugawa Kyohei
Published: March 2014

Recently, the number of people who need powered wheelchairs has been increasing due to aging society. Riding comfort is very important for people who use powered wheelchairs. In addition, wheelchairs must respond well to a velocity command signal with a joystick controller because collision must be avoided. The relation between ride comfort and fast response is a trade-off one. To solve these problems, a suitable reference torque signal should be designed. Thus, we propose a control system for powered wheelchairs that can reduce the vibration caused to the human head and upper body and achieve a fast response. Moreover, to guarantee robustness against parameter variations such as human weight and the friction of joints, a two-degrees-of-freedom control system that consists of feedforward and feedback controllers has been designed. We have designed a feedforward control input that uses the nil-mode-exciting (NME) profiler, which is called a “preshaping profiler”. This preshaping profiler has a low-pass-shaped frequency characteristic. Therefore, no residual vibrations are caused at a frequency higher than a certain frequency (the sampling function frequency). In this study, the sampling function frequency has been designed in consideration of both vibration and response. To improve robustness against the variation of model parameters such as weight and friction, we have designed a wheel velocity feedback control added to the feedforward control. To verify the effectiveness of the proposed method, several numerical simulations have been carried out.
Maneuver Based Design of Passive-Assist Devices: A Comparison of Parallel and Serial Systems
Authors: Brown W. Robert , Ulsoy A. Galip
Published: March 2014

A comparison of serial, parallel, and dual Passive Assist Devices (PADs) designed using energy minimization based on a known maneuver is presented. Implementation of a PAD can result in an improvement in system performance with respect to efficiency, reliability, and/or safety. In previous work we demonstrated this concept experimentally on a single link robot arm augmented with a torsional spring in parallel. Here we show that the concept can extended to serial and dual systems as well. To make the optimization converge more quickly we introduce a new initial design using a weighted force displacement curve fit. We provide engineering insight into why different types of PADs perform differently depending on the maneuver and offer guidelines on how to select a specific type based on the application. Finally, we demonstrate this design process and selection procedure on a 3-link manipulator arm and show that a combination of parallel and dual PADs could reduce energy consumption by up to 78%.
A New Rotary Position-Control System With Color Sensing
Authors: Kwon Young-shin , Kim Won-jong
Published: March 2014

This paper presents a new rotary position-control system using a color sensor. The angle sensing mechanism is based on the working principle of a red-green-blue (RGB) sensor that measures the radiant-intensity variation of the light reflected on the color surface. The optical-power propagation mechanism from a light-emitting diode (LED) source to the RGB sensor’s voltage is investigated using the light reflected on the designated-RGB codes of the cylindrical color-track surface. The nonlinearity due to a color printer and a paper roughness is compensated for through iterative comparisons with the reference angle achieved from a precision potentiometer. The performance of this new absolute angle sensor is validated using a rotary mechanical system with a cylindrical inertia controlled by a lead compensator. The stability of the positioning system is also investigated with the frequency response. Eventually, the feasibility of this new rotary angle sensor with the cost-effective and non-contact sensing mechanism is demonstrated.
Optimal Control of Office Plug-Loads for Commercial Building Demand Response
Authors: Arnold Daniel B. , Sankur Michael D. , Auslander David M.
Published: March 2014

While historically the electrical energy resource a commercial building may utilize during a Demand Response (DR) event has been limited to building HVAC and/or lighting systems, enabling technologies such as smart power strips (SPSs) and Energy Information Gateways (EIGs) have made distributed control over commercial office plug loads a reality. This paper investigates coordinated optimal control over plug loads in a commercial building during a DR event. Control over local office plug loads is accomplished via the use of a software entity, the Energy Information Gateway, which employs a binary integer linear program to determine which loads are shed. Individual EIGs are managed by another piece of software, the Central Building Controller (CBC), which can adjust parameters in the individual EIG optimal control algorithm. The proposed control structure is tested via the EIGs managing physical appliances in an actual office, and in simulations of the CBC managing virtual Gateways.
Experimental Evaluation of Approach Behavior for Autonomous Surface Vehicles
Authors: Bertaska Ivan R. , Alvarez Jose , Sinisterra Armando , von Ellenrieder Karl , Dhanak Manhar , Shah Brual , Švec Petr , Gupta Satyandra K.
Published: March 2014

This article presents an experimental assessment of an Unmanned Surface Vehicle (USV) executing an approach behavior to several stationary targets in an obstacle field. A lattice-based trajectory planner is implemented with a priori knowledge of the vehicle characteristics. In parallel, a low-level controller is developed for the vehicle using a proportional control law. These systems are integrated on the USV control system using the Lightweight Communications and Marshalling (LCM) message passing system. Filtered vehicle-state information from onboard sensors is passed to the planner, which returns a least-cost, dynamically feasible trajectory for achieving the ascertained goal. The system was tested in a 750 m by 150 m area of the US Intracoastal Waterway in South Florida in the presence of wind and wave disturbances to characterize its effectiveness in a real-world scenario. The vehicle was able to replicate behavior predicted in simulations when navigating around obstacles. The approach distance to each target was favorably lower than the user-defined limit. Owing to the fact that the USV uses differential thrust for steering, the vehicle tracked the planned trajectories better at lower speeds.
Planning the Minimum Time Course for Autonomous Underwater Vehicle in Uncertain Current
Authors: Hurni Michael A. , Kiriakidis Kiriakos , Nicholson John W.
Published: March 2014

The authors developed an approach to a “best” time path for Autonomous Underwater Vehicles sailing uncertain currents. The numerical optimization tool DIDO is used to compute minimum time paths for a sample of currents between ebb and flow. A simulated meta-experiment is performed where the vehicle traverses the resulting paths under different current strengths per run. The fastest elapsed time emerges from a payoff table.
Active Non-Intrusive System Identification for Cardiovascular Monitoring: Part II — Development of System Identifiction Algorithm
Authors: Fazeli Nima , Hahn Jin-Oh
Published: March 2014

In this paper, we present an innovative active non-intrusive system identification approach to cardiovascular monitoring. The proposed approach is based on a dual collocated actuator-sensor system for cardiovascular system identification, in which the actuators actively excite the arterial tree to create rich and informative trans-mural pressure waves traveling in the arterial tree, which are then non-intrusively measured by the collocated sensors. In our previous work, we developed a mathematical model to reproduce the propagation of intra-vascular (arterial) and extra-vascular (artificial) pressure waves along the arterial tree. Then, we used a dual (radial-femoral) blood pressure cuff system as a prototype dual collocated actuator-sensor system to demonstrate the proposed methodological framework to create rich trans-mural pressure waves as well as to non-intrusively reconstruct them from sensor measurements. In this follow-up work, we propose a novel system identification algorithm to derive cardiovascular system dynamics and reconstruct central aortic blood pressure waveform from the trans-mural pressure waves observed at the peripheral locations. It was successfully demonstrated that the system identification algorithm was able to reconstruct the central aortic blood pressure accurately, and that its performance was superior to the passive non-intrusive approach.
Two Degree-of-Freedom Hysteresis Compensation for a Dynamic Mirror With Antagonistic Piezoelectric Stack Actuation
Authors: Mynderse James A. , Chiu George T. C.
Published: March 2014

A methodology for designing a low-computation, high-bandwidth strategy for closed-loop control of a hysteretic system without a priori knowledge of the desired trajectory is presented. The resulting two degree-of-freedom hysteresis control strategy is applied to a dynamic mirror with antagonistic piezoelectric stack actuation. Hysteresis compensator is performed by a finite state machine switching polynomials for hysteresis inversion based on the input signal slope. Residual error after hysteresis compensation is corrected by an LQR feedback controller. Experimental results demonstrate effectiveness of the hysteresis compensator and closed-loop system under the proposed hysteresis control strategy. For the triangular input signal tested, the closed-loop system achieves a 91.5% reduction in hysteresis uncertainty with 60 kHz sample rate.
Improving Cardiopulmonary Resuscitation (CPR) by Dynamic Variation of CPR Parameters
Authors: Jalali Ali , Berg Robert A. , Nadkarni Vinay M. , Nataraj C.
Published: March 2014

Cardiopulmonary resuscitation (CPR) is a commonly used procedure and plays a critical role in saving the lives of patients suffering from cardiac arrest. This paper is concerned with the design of a dynamic technique to optimize the performance of CPR and to consequently improve its outcome, the survival rate. Current American Heart Association (AHA) guidelines treat CPR as a static procedure with fixed parameters. These guidelines set fixed values for CPR parameters such as compression to ventilation ratio, chest compression depth, etc., with an implicit assumption that they are somehow “optimal,” which has not been really substantiated. In this study, in a quest to improve this oft-used procedure, an interactive technique has been developed for dynamically changing the CPR parameters. Total blood gas delivery which is combination of systemic oxygen delivery and carbon dioxide delivery to the lungs has been defined as the objective function, and a sequential optimization procedure has been explored to optimize the objective function by dynamically adjusting the CPR parameters. The results of comparison between the sequential optimization procedure and the global optimization procedure show that the sequential optimization procedure could significantly enhance the effectiveness of CPR.
Snakeboard Motion Planning With Local Trajectory Information
Authors: Dear Tony , Hatton Ross L. , Travers Matthew , Choset Howie
Published: March 2014

We address trajectory generation for the snakeboard, a system commonly studied in the geometric mechanics community. Our approach derives a solution using body coordinates and local trajectory information, leading to a more intuitive solution compared to prior work. The simple forms of the solution clearly show how they depend on local curvature and desired velocity profile, allowing for a description of some simple motion primitives. We readily propose techniques to navigate paths, including those with sharp corners, by taking advantage of the snake-board’s singular configuration, as well as discuss some implications of torque limits.
Asymptotic Stability Method for PID Controller Tuning in a Backhoe Machine
Authors: Mastalli Carlos , Ralev Dimitar , Certad Novel , Fernandez-Lopez Gerardo
Published: March 2014

This paper presents the modeling and study of dynamic behavior of a backhoe machine for tuning of PID controller. The tuning procedure of PID controller is performed, in detailed, for the case of a typical operation, digging a foundation and truck loading. This tuning procedure guarantees the local asymptotic stability in the sense of Lyapunov of origin of the closed-loop equation of PID controller. Besides the tuning procedure requires the knowledge of certain properties of dynamic model, which are dependent on the desired trajectory. Finally it is demonstrated that this tuning procedure proves to be effective, and also robust in the execution of other tasks performed by the backhoe machine.
A Model-Based Predictive Control Approach for a Building Cooling System With Ice Storage
Authors: Dehkordi Vahid R. , Candanedo José A.
Published: March 2014

This paper presents a model predictive control (MPC) algorithm designed for the cooling system of a small commercial building under a time-dependent electricity price profile. The proposed approach includes a problem formulation in terms of cooling power, a variable-length prediction horizon and the consideration of the equipment duty cycle as a constraint in the optimization algorithm. The cooling system is equipped with an ice bank for thermal energy storage. A simple linear building thermal model is used to calculate the required amount of cooling power to maintain thermal comfort. The MPC algorithm uses this information to find the optimal operating points for the chiller and the ice bank to minimize the electric energy cost. The results of the MPC algorithm are compared against those of the reactive rule-based control algorithm currently in use in the building.
Formulation for Interaction Analysis Between Continuous and Discrete Structures Subject to Moving Loads Applied to Turning
Authors: Madariaga Jon , Tsao Tsu-Chin , Ruiz Ismael
Published: March 2014

A control oriented formulation of continuous structures interacting with moving and/or fixed structures is presented. Machining of long parts in a lathe is presented in order to illustrate the methodology. The system is time-varying in nature due to the movement of the cutting tool during the machining process. However the invariant part corresponding to the structure dynamics (tool and workpiece) and the time varying part corresponding to the movement of the cutting point can be separated. The link between the two is given by the eigenfunctions relating the output of the dynamic part with the actual displacement within the workpiece continuum. This splitted formulation allows modular design approaches, facilitating the inclusion and analysis of further elements such as flexible supports and/or allowing direct modifications of the characteristics of the different structural elements individually (considered vibration modes, etc.). For the presented turning example the implications of workpiece flexibility and the inclusion of flexible supports at different locations on regenerative chatter stability are also discussed.
Spatial Feature Matching for Visual Odometry: A Parametric Study
Authors: Clayton Garrett M. , Fabian Joshua R.
Published: March 2014

The goal of this paper is to perform a parametric study on a newly developed visual odometry algorithm for use with color-depth (RGB-D) camera pairs, such as the Microsoft Kinect. In this algorithm, features are detected in the color image and converted to 3D points using the depth image. These features are then described by their 3D location and matched across subsequent frames based on spatial proximity. The visual odometry is then calculated using a one-point inverse kinematic solution. The primary contribution of this work is the identification of critical operating parameters associated with the algorithm, the analysis of their effects on the visual odometry performance, and the verification of the analysis using experimentation.
LPV Control of an Electronic Throttle
Authors: Zhang Shupeng , White Andrew , Zhu Guoming , Yang Jie J.
Published: March 2014

In this paper, a discrete-time electronic throttle model was developed based upon the parameters obtained through system identification. To design gain-scheduling controllers using LPV (linear parameter varying) scheme, the throttle was modeled as an LPV system, where the vehicle battery voltage and the non-linear friction coefficient are the measurable time-varying parameters. Gain-scheduling H 2 controller was designed for the LPV throttle system using the linear matrix inequality (LMI) convex optimization approach. The designed controller is validated through simulations and show that the proposed controller provides improved performance over the baseline fixed gain controller.
Adaptive Traction Control for Non-Rigid Tire-Wheel Systems
Authors: Adcox John , Ayalew Beshah
Published: March 2014

The designs of commercial Anti-Lock Braking Systems often rely on assumptions of a torsionally rigid tire-wheel system. However, variations in tire/wheel technologies have resulted in lower torsional stiffnesses that cannot be captured well using these rigid wheel assumptions. This paper presents an adaptive nonlinear controller based on a model that incorporates sidewall flexibility, and transient & hysteretic tread-ground friction effects. The sidewall stiffness and damping and as well as tread parameters are assumed to be unknown and subsequently estimated through a set of gradient-based adaptation laws. A virtual damper is introduced via a backstepping controller design to address difficulties associated with tires with low torsional damping.