bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparing Cerebralcare Granule and aspirin for neurological dysfunction in acute stroke in real‐life practice
Authors: Zhao Luqing , Liao Lianming , Hu Fengyun
Published: January 2016

Background

Cerebralcare Granule (CG) is a polyherbal Chinese medicine that has been shown to have neuroprotective effects in experimental models of stroke. We compared the efficacy and safety of CG with aspirin in patients with acute stroke.

Methods

For this open‐label, controlled trial, we recruited patients with angiographically confirmed strokes and US National Institutes of Health Stroke Scale (NIHSS) scores of 4–22 within 2 weeks of symptom onset; recruitment was performed at 55 sites in China. Patients received CG or aspirin. The primary efficacy end‐point was neurological function. Analyses were done by intention to treat. Patients were measured for NIHSS, Montreal Cognitive Assessment, and Mini‐Mental State Examination scores and Barthel index at baseline and at 4, 8, and 12 weeks after treatment.

Results

Between January 2013 and January 2014, we treated 1963 patients with CG and 1288 patients with aspirin. Baseline NIHSS, Mini‐Mental State Examination, and Montreal Cognitive Assessment scores were comparable between the two groups. Patients in the CG group had a greater improvement than the aspirin group in terms of NIHSS (P < 0.01) and Barthel index at 4, 8, and 12 weeks. At 12 weeks, patients in the CG group had a greater improvement than the aspirin group in terms of Mini‐Mental State Examination (P < 0.01) and Montreal Cognitive Assessment (P < 0.05). Adverse reactions were similar between the two groups.

Conclusions

This large‐scale, controlled trial indicated that CG may be a useful treatment in the management of post‐stroke patients.
Rapid eye movement sleep without atonia may help diagnose Lewy body disease in middle‐aged and older patients with somatic symptom disorder
Authors: Munechika Takayuki , Fujishiro Hiroshige , Okuda Masato , Iwamoto Kunihiro , Torii Youta , Iritani Shuji , Ozaki Norio
Published: January 2016

Background

Lewy body disease (LBD), including Parkinson's disease (PD) and dementia with Lewy bodies (DLB), is defined pathologically as degeneration in the central and peripheral nervous system associated with Lewy bodies. Somatic symptom disorder often predates the clinical diagnosis of PD and DLB. It is crucial to make an initial diagnosis of LBD in patients with psychiatric symptoms because administering psychotropic drugs often causes or exacerbates extrapyramidal signs. Given the close association between rapid eye movement (REM) sleep behaviour disorder and LBD, REM sleep without atonia on polysomnography may help to diagnose LBD in middle‐aged and older patients with somatic symptom disorder.

Methods

We reviewed the clinical profiles of five patients with an initial diagnosis of somatic symptom disorder who exhibited REM sleep without atonia on polysomnography. There were three men and two women, with a mean age of 68.4 years (range: 55.0–78.0 years). The mean Mini‐Mental State Examination score was 26 (range: 22–30).

Results

Only two patients had a clinical history of dream‐enacting behaviour and fulfilled the clinical criteria for REM sleep behaviour disorder, but clinical conditions in the other three patients corresponded to subclinical REM sleep behaviour disorder. Final clinical diagnoses were made as probable DLB in three patients; two patients did not meet the clinical criteria for PD or DLB. Neurological examinations revealed mild extrapyramidal signs in these two patients, and their scores on the motor component of the Unified Parkinson's Disease Rating Scale were 8 and 5 points, and their Mini‐Mental State Examination scores were 30 points. Neither patient exhibited dream‐enacting behaviour, but both had constipation. Cardiac 123I‐metaiodobenzylguanidine scintigraphy revealed mild increased washout rates.

Discussion

REM sleep without atonia may provide an opportunity to identify LBD in patients with somatic symptom disorder, even before they fulfil the clinical criteria for PD or DLB. Continued follow‐up will be needed to determine whether these psychiatric patients are in the prodromal stage of PD or DLB.
An investigation into the roles of open innovation collaboration managers
Authors: Ollila Susanne , Yström Anna
Published: January 2016

The concept of open innovation has gained traction among practitioners and academics. Many different aspects of open innovation have been researched, but the question of how to manage open innovation collaboration in order to achieve the desired knowledge flow across organizational boundaries remains only partly answered. Consequently, this article argues for the need to complement prior firm‐centric perspectives by investigating the roles of senior management in the postmodern form of organizing that characterizes open innovation collaboration. A more in‐depth understanding of managerial roles in this context can increase the chances of fruitful collaboration. Thus, the article uses an inductive, interview‐based approach to explore senior management roles in two institutionalized open innovation collaborations, thereby creating an initial conceptualization of the role of managers in open innovation and forming a basis for further studies on open innovation management. In this respect, the article identifies and discusses additional managerial roles that appear to be crucial for open innovation collaborations. These roles are those of afacilitator, tactician, andsensegiver.
Nonsectarian welfare statements
Authors: Sunstein Cass R.
Published: January 2016

How can we measure whether national institutions in general, and regulatory institutions in particular, are dysfunctional? A central question is whether they are helping a nation's citizens to live good lives. A full answer to that question would require a great deal of philosophical work, but it should be possible to achieve an incompletely theorized agreement on a kind of nonsectarian welfarism, emphasizing the importance of five variables: subjective well‐being, longevity, health, educational attainment, and per capita income. In principle, it would be valuable to identify the effects of new initiatives (including regulations) on all of these variables. In practice, it is not feasible to do so; assessments of subjective well‐being present particular challenges. In their ideal form, Regulatory Impact Statements should be seen as Nonsectarian Welfare Statements, seeking to identify the consequences of regulatory initiatives for various components of welfare. So understood, they provide reasonable measures of regulatory success or failure, and, hence, a plausible test of dysfunction. There is a pressing need for improved evaluations, including both randomized controlled trials and ex post assessments.
Distance Shrinkage and Euclidean Embedding via Regularized Kernel Estimation
Authors: Zhang Luwan , Wahba Grace , Yuan Ming
Published: January 2016

Although recovering a Euclidean distance matrix from noisy observations is a common problem in practice, how well this could be done remains largely unknown. To fill in this void, we study a simple distance matrix estimate based on the so-called regularized kernel estimate. We show that such an estimate can be characterized as simply applying a constant amount of shrinkage to all observed pairwise distances. This fact allows us to establish risk bounds for the estimate, implying that the true distances can be estimated consistently in an average sense as the number of objects increases. In addition, such a characterization suggests an efficient algorithm to compute the distance matrix estimator, as an alternative to the usual second-order cone programming which is known not to scale well for large problems. Numerical experiments and an application in visualizing the diversity of Vpu protein sequences from a recent study of human immunodeficiency virus type 1 further demonstrate the practical merits of the method proposed.
Bayesian Inference for Intratumour Heterogeneity in Mutations and Copy Number Variation
Authors: Lee Juhee , Müller Peter , Sengupta Subhajit , Gulukota Kamalakar , Ji Yuan
Published: January 2016

Tissue samples from the same tumour are heterogeneous. They consist of different subclones that can be characterized by differences in DNA nucleotide sequences and copy numbers on multiple loci. Inference on tumour heterogeneity thus involves the identification of the subclonal copy number and single-nucleotide mutations at a selected set of loci. We carry out such inference on the basis of a Bayesian feature allocation model. We jointly model subclonal copy numbers and the corresponding allele sequences for the same loci, using three random matrices, L, Z and w, to represent subclonal copy numbers (L), the number of subclonal variant alleles (Z) and the cellular fractions (w) of subclones in one or more tumour samples respectively. The unknown number of subclones implies a random number of columns. More than one subclone indicates tumour heterogeneity. Using simulation studies and a real data analysis with next generation sequencing data, we demonstrate how posterior inference on the subclonal structure is enhanced with the joint modelling of both structure and sequencing variants on subclonal genomes. An R package is available from http://cran.r-project.org/web/packages/BayClone2/index.html.
Realtime Classification of Fish in Underwater Sonar Videos
Authors: Bothmann Ludwig , Windmann Michael , Kauermann Göran
Published: January 2016

Dual-frequency identification sonar delivers video-like underwater images which allow the investigation of fish behaviour even in cloudy and muddy water. Generally, images are recorded in a resolution of up to 10 pictures per second, so that practically one obtains a video of underwater movements. These videos allow ecologists to observe, count or investigate fish behaviour. We focus on automatic classification of fish based on such sonar videos. After appropriate preprocessing of the videos, we show how we can count and classify fish into different species on the basis of their shape and movement. The procedures developed work in realtime, i.e. data processing and classification of video sequences are faster than the length of the video sequences themselves.
The participant's perspective: learning from an aggression management training course for nurses. Insights from a qualitative interview study
Authors: Heckemann Birgit , Breimaier Helga Elisabeth , Halfens Ruud J.G. , Schols Jos M.G.A. , Hahn Sabine
Published: January 2016

Background

Aggression management training for nurses is an important part of a comprehensive strategy to reduce patient and visitor aggression in healthcare. Although training is commonplace, few scientific studies examine its benefits.

Aim

To explore and describe, from a nurse's perspective, the learning gained from attending aggression management training.

Design and methods

This was a descriptive qualitative interview study. We conducted semi‐structured individual interviews with seven nurses before (September/October 2012) and after they attended aggression management training (January/February 2013). Interview transcripts were content‐analysed qualitatively.

Ethical issues

The study plan was reviewed by the responsible ethics committees. Participants gave written informed consent.

Findings

Aggression management training did not change nurses’ attitude. Coping emotionally with the management of patient and visitor aggression remained a challenge. Nurses’ theoretical knowledge increased, but they did not necessarily acquire new strategies for managing patient/visitor aggression. Instead, the course refreshed or activated existing knowledge of prevention, intervention and de‐escalation strategies. The training increased nurses' environmental and situational awareness for early signs of patient and visitor. They also acquired some strategies for emotional self‐management. Nurses became more confident in dealing with (potentially) aggressive situations. While the training influenced nurses’ individual clinical practice, learning was rarely shared within teams.

Conclusions

Aggression management training increases skills, knowledge and confidence in dealing with patient or visitor aggression, but the emotional management remains a challenge. Future research should investigate how aggression management training courses can strengthen nurses’ ability to emotionally cope with patient and visitor aggression. More knowledge is needed on how the theoretical and practical knowledge gained from the training may be disseminated more effectively within teams and thus contributed to the creation of low‐conflict ward cultures.
Dose Timing of Aminoglycosides in Hemodialysis Patients: A Pharmacology View
Authors: Eschenauer Gregory A. , Lam Simon W. , Mueller Bruce A.
Published: January 2016

Aminoglycosides for patients undergoing intermittent hemodialysis (IHD) have traditionally been dosed at half the normal dose administered at the end of a hemodialysis session. Several investigations have suggested that administering higher doses preceding or with the initiation of dialysis would more readily optimize pharmacodynamic parameters. However, the selection of an optimal aminoglycoside dosing strategy in patients receiving IHD is complex and requires consideration of numerous factors, precluding a singular approach. By reviewing aminoglycoside pharmacokinetics, pharmacodynamics, risks for toxicity and resistance development, and practical considerations, we derive indication‐ and setting‐ specific recommendations. We identify some areas (definitive therapy of gram‐negative infections in patients receiving predictable hemodialysis sessions, for example) where dosing preceding or with the initiation of dialysis is optimal and feasible, and others (gram‐positive synergy, unstable patients with poor/unpredictable vascular access) where postdialysis dosing remains preferred. Finally, given the dearth of data exploring the pharmacodynamics and clinical outcomes of IHD patients receiving aminoglycoside therapy, we identify several key questions in need of investigation.
The Impact of Arteriovenous Fistulae for Hemodialysis on the Cardiovascular System
Authors: Rao Nitesh N. , Dundon Benjamin K. , Worthley Matthew I. , Faull Randall J.
Published: January 2016

An arteriovenous fistula (AVF) is critical for the provision of optimal chronic hemodialysis. Its creation causes significant hemodynamic alterations in cardiovascular parameters, and can result in progressive left and right heart failure. Despite successful kidney transplantation, many patients retain a functional AVF indefinitely, which may contribute to ongoing adverse cardiovascular outcomes. A similar high risk:benefit ratio may exist in peritoneal dialysis patients with “backup” AVF.
The stigma of making a living from garbage: Meta‐sterotypes of trash‐pickers in León (Nicaragua)
Authors: Vázquez José Juan
Published: January 2016

The article analyzes various aspects related to the meta‐stereotype of 99 trash pickers who made their living from the garbage dumps in León (Nicaragua). This group is difficult to access, heavily stigmatized, and lives in extreme poverty. All the pickers in the city were interviewed using a heteroapplied structured interview. The results show that people who obtained their livelihood from garbage in the city of León had a mainly negative meta‐stereotype, albeit one to which was some extent indulgent, which could have a negative impact on their processes of social inclusion. The content of the meta‐stereotype had a high degree of uniformity, with few variations between the respondents. However, some differences were observed in the use of some attributes in the meta‐stereotype according to age, cohabitation with a partner and/or with parents, income level, engagement in paid work apart from picking garbage and the respondents' expectations for the future.
Adults’ Perceptions of Children's Science Abilities and Interest After Participating in a Family Science Night
Authors: Yanowitz Karen L. , Hahs‐Vaughn Debbie L.
Published: January 2016

The goal of this research was to examine adults’ and children's perceptions of participating in a family science night event, especially in the context of parental belief about children's science abilities. Family science nights are becoming increasingly popular and are used in a wide range of settings. During family science nights, adults and students jointly engaged in a variety of science activities. Results revealed that adults, 90% of whom were parents of attending students, reported learning more about children's interests and abilities in science. Students also agreed that that the adults had learned more about their abilities and interests. Personal characteristics of adults and children, such as gender and ethnicity, were not found to have any relationship to ratings.
Molecular Basis for the Interaction Between AP4 β4 and its Accessory Protein, Tepsin
Authors: Frazier Meredith N. , Davies Alexandra K. , Voehler Markus , Kendall Amy K. , Borner Georg H. H. , Chazin Walter J. , Robinson Margaret S. , Jackson Lauren P.
Published: January 2016

The adaptor protein 4 (AP4) complex (ϵ/β4/μ4/σ4 subunits) forms a non‐clathrin coat on vesicles departing the trans‐Golgi network. AP4 biology remains poorly understood, in stark contrast to the wealth of molecular data available for the related clathrin adaptors AP1 and AP2. AP4 is important for human health because mutations in any AP4 subunit cause severe neurological problems, including intellectual disability and progressive spastic para‐ or tetraplegias. We have used a range of structural, biochemical and biophysical approaches to determine the molecular basis for how the AP4 β4 C‐terminal appendage domain interacts with tepsin, the only known AP4 accessory protein. We show that tepsin harbors a hydrophobic sequence, LFxG[M/L]x[L/V], in its unstructured C‐terminus, which binds directly and specifically to the C‐terminal β4 appendage domain. Using nuclear magnetic resonance chemical shift mapping, we define the binding site on the β4 appendage by identifying residues on the surface whose signals are perturbed upon titration with tepsin. Point mutations in either the tepsin LFxG[M/L]x[L/V] sequence or in its cognate binding site on β4 abolish in vitro binding. In cells, the same point mutations greatly reduce the amount of tepsin that interacts with AP4. However, they do not abolish the binding between tepsin and AP4 completely, suggesting the existence of additional interaction sites between AP4 and tepsin. These data provide one of the first detailed mechanistic glimpses at AP4 coat assembly and should provide an entry point for probing the role of AP4‐coated vesicles in cell biology, and especially in neuronal function.
Producing megakaryocytes from a human peripheral blood source
Authors: Ivetic Nikola , Nazi Ishac , Karim Nadia , Clare Rumi , Smith James W. , Moore Jane C. , Hope Kristin J. , Kelton John G. , Arnold Donald M.
Published: January 2016

BACKGROUND

Cultured megakaryocytes could prove useful in the study of human diseases, but it is difficult to produce sufficient numbers for study. We describe and evaluate the use of an expansion process to develop mature megakaryocytes from peripheral blood–derived human hematopoietic stem and progenitor cells (HSPCs).

STUDY DESIGN AND METHODS

HSPCs (CD34+) were isolated from peripheral blood by positive selection and expanded using an optimal CD34+ expansion supplement. We evaluated megakaryocyte growth, maturation, and morphology in response to thrombopoietin (TPO) stimulation using flow cytometry and electron microscopy. TPO demonstrated a dose‐dependent stimulatory effect on both megakaryocyte number and maturation.

RESULTS

From 90 to 120 mL of unmanipulated peripheral blood, we isolated a mean of 1.5 × 105 HSPCs (1.5 × 103 cells/mL of whole blood). HSPCs expanded nine‐fold after a 4‐day culture using an expansion supplement. Expanded cells were cultured for an additional 8 days with TPO (20 ng/mL), which resulted in a 2.9‐fold increase in megakaryocytic cells where 83% of live cells expressed CD41a+, a marker of megakaryocyte commitment, and 50% expressed CD42b+, a marker for megakaryocyte maturation. The expanded HSPCs responded to TPO stimulation to yield more than 1.0 × 106 megakaryocytes. This cell number was sufficient for morphologic studies that demonstrated these expanded HSPCs produced mature polyploid megakaryocytes capable of forming proplatelet extensions.

CONCLUSIONS

Peripheral blood HSPCs can be expanded and differentiated into functional, mature megakaryocytes, a finding that supports the use of this process to study inherent platelet (PLT) production disorders as well as study factors that impair normal PLT production.
Initial analytic quality assessment and method comparison of an immunoassay for adrenocorticotropic hormone measurement in equine samples
Authors: Irvine Katherine L. , Burt Kay , Hill Andrew J. , Shaw Stephanie , Papasouliotis Kostas
Published: January 2016

Background

Equine pituitary pars intermedia dysfunction (PPID) may be diagnosed by measuring baseline plasma adrenocorticotrophic hormone (ACTH). The Immulite 1000 analyzer uses an automated chemiluminescence enzyme assay, previously validated for measuring equine ACTH. Recently, an automated bench‐top immunoassay analyzer (AIA‐360), designed for analytes in people, became available for veterinary use.

Objectives

Objectives were to evaluate analytic performance of the AIA immunoassay for measuring equine ACTH, and compare the results with those obtained by the Immulite.

Methods

Adrenocorticotrophic hormone was measured in plasma samples from 52 clinical cases. For the AIA, within‐ and between‐run coefficients of variation (CV) were assessed, linearity and recovery studies performed, and observed total error (TEobs) calculated. Correlation and agreement between the 2 analyzers were also evaluated.

Results

Within‐run and between‐run CV of the AIA ranged from 2.3% to 4% and 3.5% to 8%, respectively. ACTH recoveries ranged from 89.5% to 115.9%. TEobs at 26.5 pg/mL ACTH was 4.1 pg/mL. The ACTH results (median: 25.9 pg/mL; range: 4.3–276.7 pg/mL) with AIA were significantly lower (P < .0001) than with the Immulite (median: 29.9 pg/mL; range: 10.3–639.0 pg/mL). Correlation between the 2 analyzers was r = 0.882 (P < .0001), with a significant bias for the AIA of −16 pg/mL. The 2 methods were not identical within inherent imprecision.

Conclusion

The AIA is precise for measuring ACTH in horses. Although correlation between the instruments is good, the values obtained by the immunoassays cannot be used interchangeably and should be interpreted using reference intervals established for each analyzer to avoid false negatives. Diagnostic sensitivity and specificity of the AIA‐360 should be evaluated before clinical use.
Evaluation of agreement and trending ability between transpulmonary thermodilution and calibrated pulse contour and pulse power cardiac output monitoring methods against pulmonary artery thermodilution in anesthetized dogs
Authors: Kutter Annette P.N. , Bettschart‐Wolfensberger Regula , Romagnoli Noemi , Bektas Rima N.
Published: January 2016

Objective

To assess agreement and trending ability of transpulmonary thermodilution (TPTD), calibrated pulse contour (PiCCO), and pulse power (PulseCO) methods compared to pulmonary artery thermodilution (PATD) for determination of cardiac output (CO) in anesthetized dogs.

Design

Experimental, prospective study.

Setting

University teaching hospital.

Animals

Six adult Beagle dogs.

Interventions

Dogs were anesthetized with sevoflurane and instrumented with pulmonary and femoral artery thermodilution catheters. CO was measured at baseline and at 5, 15, 30, 45, 60, 120, 180, and 240 minutes after IV administration of ketamine or s‐ketamine. Baseline PATD and TPTD calibrated PulseCO and PiCCO, respectively. Agreement and trending ability was analyzed with Bland–Altman, concordance, and polar plot methodology.

Measurements and Main Results

Median (range) CO values of 2.27 (0.98–3.4) L/min were measured with PATD, and 2.8 (1.9–4.04) L/min with TPTD, which resulted in a mean bias (± standard deviation) of −0.66 (± 0.36) L/min. Concordance rate was 91% and radial limits of agreement (RLOA) were ±35°. PATD against PiCCO resulted in a mean bias of −0.71 (± 0.62) L/min and PATD against PulseCO in a mean bias of 0.13 (± 0.46) L/min. The continuous techniques resulted in concordance rates of 77% for PATD‐PiCCO and 74% for PATD‐PulseCO and RLOA of ±57° and ±60°, respectively.

Conclusions

Intermittent TPTD showed marginal trending ability, while continuous pulse contour and pulse power methods showed poor trending ability over a 4‐hour period. The poor performance and possible side effects of the methods tested in this study suggest that they should not be recommended for use in critical patients.
Survey of Intraoperative Bacterial Contamination in Dogs Undergoing Elective Orthopedic Surgery
Authors: Andrade Natalia , Schmiedt Chad W. , Cornell Karen , Radlinsky MaryAnn G. , Heidingsfelder Lauren , Clarke Kevin , Hurley David J. , Hinson Whitney D.
Published: January 2016

Objective

To investigate the frequency, source, and risk factors of intraoperative (IO) surgeon and patient bacterial contamination during clean orthopedic surgeries, and to investigate the relationship between IO contamination and surgical site infection (SSI) in dogs.

Study Design

Prospective clinical study.

Sample Population

Client‐owned dogs undergoing stifle surgery (n = 100).

Methods

IO cultures were taken in each case from surgical foot wrap, peri‐incisional skin, surgical gloves, and the surgical team's hands. The environment (operating room [OR] lights, computers, scrub sink faucet, anesthesia gurney, and radiology table) was sampled every 5 months. Bacteria were identified and the contamination of each case was categorized. All gloves from the surgical team were collected and tested for perforations using a water infusion test. Cases were followed for at least 8 weeks to determine the presence or absence of SSI. Perioperative variables were evaluated for association with IO contamination and SSI.

Results

Bacterial isolates were yielded from 81% of procedures from 1 or more sources; 58% had positive hand cultures, 46% had positive glove cultures, 23% had positive patient skin cultures, and 12% had positive foot wrap cultures. Staphylococcus spp. was the most commonly recovered bacteria. There was no apparent association between IO contamination and SSI. The highest level of environmental contamination was associated with the scrub sink faucet, followed by the radiology table, anesthesia gurney, and OR computers. The IO glove perforation rate was 18%.

Conclusion

Clean orthopedic procedures commonly had clinically insignificant bacterial contamination. In our study, bacteria responsible for SSI did not appear to colonize the patient in the OR.
Design of a 6-DOF Robotic Gait Training System With Closed-Chain Foot Initiated Kinematics Control
Authors: Liu Wei , Kovaleski John , Hollis Marcus
Published: January 2016

Robotic assisted rehabilitation, taking advantage of neuroplasticity, has been shown to be helpful in regaining some degree of gait performance. Robot-applied movement along with voluntary efferent motor commands coordinated with the robot allows optimization of motion training. We present the design and characteristics of a novel foot-based 6-degree-of-freedom (DOF) robot-assisted gait training system where the limb trajectory mirrored the normal walking gait. The goal of this study was to compare robot-assisted gait to normal walking gait, where the limb moved independently without robotics. Motion analysis was used to record the three-dimensional kinematics of the right lower extremity. Walking motion data were determined and transferred to the robotic motion application software for inclusion in the robotic trials where the robot computer software was programmed to produce a gait pattern in the foot equivalent to the gait pattern recorded from the normal walking gait trial. Results demonstrated that ankle; knee and hip joint motions produced by the robot are consistent with the joint motions in walking gait. We believe that this control algorithm provides a rationale for use in future rehabilitation, targeting robot-assisted training in people with neuromuscular disabilities such as stroke.
Human-Aware Autonomous Control for Cooperative Adaptive Cruise Control (CACC) Systems
Authors: Wang Xujie , Wang Yue
Published: January 2016

This paper discusses the design of a human-aware cooperative adaptive cruise control (CACC) system that (i) takes into account driver comfort in autonomous cruise control, and (ii) provides assistive corrections to avoid driver errors. To incorporate driver characteristics into system controller design, two self-learning algorithms are used to estimate driver’s preferred time headway. We then develop a human-like blending control for CACC based on a model predictive control (MPC)-type method, which integrates the driver comfort, traffic efficiency, and fuel economy criteria. Furthermore, a driving assistance controller is developed to help human driver to maintain string stability in platoon. Simulation results show that (i) the human-like CACC design can significantly improve driving experience, and (ii) with the help of the assistive controller, string stability is satisfied for both exclusively autonomous CACC and when the CACC switches to manual driving in a platoon.
Active and Passive Vibration Control Using Compact Damping Patches: Assessment of a Reduced Order Model for an Euler Beam
Authors: Plattenburg Joseph , Dreyer Jason T. , Singh Rajendra
Published: January 2016

Concurrent placement of compact active and passive damping patches for vibration reduction is a developing area of research. Analytical and computational models to evaluate alternate patch configurations and structural geometries are not widely available. To overcome this void, this paper presents a simplified discrete-system model for vibrations of a beam-like structure. A disturbance input is included in the model, along with a control input from an active patch. Localized structural damping resulting from a passive patch is modeled with an equivalent loss factor. Results from the simplified model are verified using a more detailed analytical formulation, which is based on the Ritz approximation. Verification studies include the effect of a passive damping patch on modal loss factors and broadband attenuation. Finally, a few case studies are proposed which show the efficacy of the reduced-order model for parametric design studies. These studies include determining the effect of localized damping on the control system parameters that are required for attenuation of localized and global motions. The effect of patch locations on system response is also studied. This work has potential applications in industry since compact damping patches are attractive NVH treatments that add minimal weight and complexity.
Control of Networked Multiagent Systems With Uncertain Graph Topologies
Authors: Yucelen Tansel , Peterson J. Daniel , Moore Kevin L.
Published: January 2016

Multiagent systems consist of agents that locally exchange information through a physical network subject to a graph topology. Current control methods for networked multiagent systems assume the knowledge of graph topologies in order to design distributed control laws for achieving desired global system behaviors. However, this assumption may not be valid for situations where graph topologies are subject to uncertainties either due to changes in the physical network or the presence of modeling errors especially for multiagent systems involving a large number of interacting agents. Motivating from this standpoint, this paper studies distributed control of networked multiagent systems with uncertain graph topologies. The proposed framework involves a controller architecture that has an ability to adapt its feedback gains in response to system variations. Specifically, we analytically show that the proposed controller drives the trajectories of a networked multiagent system subject to a graph topology with time-varying uncertainties to a close neighborhood of the trajectories of a given reference model having a desired graph topology. As a special case, we also show that a networked multiagent system subject to a graph topology with constant uncertainties asymptotically converges to the trajectories of a given reference model. Although the main result of this paper is presented in the context of average consensus problem, the proposed framework can be used for many other problems related to networked multiagent systems with uncertain graph topologies.
Stabilization of Nonlinear Systems by Switched Lyapunov Function
Authors: Zelenak Andy , Pryor Mitch
Published: January 2016

If a Lyapunov function is known, a dynamic system can be stabilized. However, computing a Lyapunov function is often challenging. This paper takes a new approach; it assumes a basic Lyapunov-like function then seeks to numerically diminish the Lyapunov value. If the control effort would have no effect at any iteration, the Lyapunov-like function is switched in an attempt to regain control. The method is tested on four simulated systems to give some perspective on its usefulness and limitations. A highly coupled 3rd order system demonstrates the approach’s general applicability and finally the coordinated control of 7 motors for a robotic application is considered. Details on the publicly available software packages for application agnostic software and hardware environments are also presented.
Observer Based Adaptive Estimation/Cancellation of Unmatched Sinusoidal Disturbances in Known LTI Systems by State Derivative Measurement
Authors: Basturk Halil Ibrahim
Published: January 2016

In this paper, an adaptive observer and backstepping controller are designed to cancel and estimate sinusoidal disturbances forcing a linear time-invariant by using only the measurements of the state-derivatives. The parametrization of the sinusoidal disturbance as the output of a known feedback system with an unknown output vector that depends on unknown disturbance parameters with the necessary filter designs enables to approach the problem as an adaptive control problem. An observer is designed for the unmeasured virtual input to apply a backstepping procedure which handles the unmatched disturbance and input condition. Firstly, it is shown that the disturbance and the unmeasured actuator state are observed perfectly in the open loop case. Secondly, the closed loop case is considered and it is proven that the equilibrium of the closed-loop adaptive system is stable and the state of the considered original system converge to zero as t → ∞ with perfect disturbance estimation. The effectiveness of the controller and the observers are illustrated with a simulation example of a third order system.
Modeling and Control of Coupled Torsional and Lateral Vibrations in Drill Strings
Authors: Hong Liu , Dhupia Jaspreet Singh
Published: January 2016

Excessive vibrations of the drill strings, e.g., the stick-slip vibration, are the primary cause of premature failures and drilling inefficiencies in oil well drilling. To investigate and suppress such vibrations, this paper studies the dynamics of drill strings using a lumped parameter model, in which both the torsional stick-slip and lateral vibrations are taken into consideration. The friction torque due to the downhole bit-rock interaction, which plays a key role in stick-slip vibration, is modeled as a hysteretic dry friction function. Simulated results of this developed model are shown to have a close qualitative agreement with the field observations in terms of stick-slip vibrations. Afterwards, a sliding mode controller is applied to mitigate the undesired vibrations of drill strings. A good control performance in suppressing the stick-slip phenomenon is demonstrated for the proposed controller. However, numerical simulations also demonstrate that the control action can excite lateral instability in the system, which can result in impacts between the drill collars and the borehole wall due to the large amplitude in lateral vibrations. Thus, a proper choice of the control parameters is essential to suppress the vibrations in the drill strings. The developed lumped parameter model describing the coupled torsional and lateral response in the controlled drill strings presented in this paper can be used to aid in offline tuning of those control variables.
Event-Triggered Adaptive Control
Authors: Albattat Ali , Gruenwald Benjamin C. , Yucelen Tansel
Published: January 2016

In this paper, we present a new adaptive control methodology that allows a desirable command performance while the proposed controller exchanges data with the physical system through a real-time network. Specifically, we utilize tools and methods from event-triggering control theory to schedule data exchange dependent upon errors exceeding user-defined thresholds and show the boundedness of the overall closed-loop system using Lyapunov stability. An illustrative numerical example is provided to demonstrate the efficacy of the proposed adaptive control approach.
Passive Control of a Hydraulic Human Power Amplifier Using a Hydraulic Transformer
Authors: Lee Sangyoon , Li Perry Y.
Published: January 2016

The hydraulic human power amplifier is a tool that uses hydraulic actuation to amplify the force that the human exerts on it. Our control objective and framework are to make the system behave like a passive mechanical tool when interacting with the human and with the work environment with a specified power scaling factor. A virtual velocity coordination control approach casts the human power amplifier problem into one of velocity coordination by generating a fictitious reference mechanical system. Force amplification becomes a natural consequence of velocity coordination. This control has been previously demonstrated using servo valves which is a major contributor to energy loss in hydraulic system. In this paper, a hydraulic transformer, which does not rely on throttling to accomplish its control function is used instead of a servo valve to achieve human power amplification. In addition, a passivity based control approach that makes use of the natural energy storage of the hydraulic actuator is used to define the flow requirement. This approach fully accounts for the non-linearity due to the pressure dynamics. The controller was experimentally validated with good force amplification and velocity coordination performance on a single degree of freedom hydraulic human power amplifier.
A Framework for Control Oriented Modeling of PEM Fuel Cells
Authors: Pence Benjamin L. , Chen Jixin
Published: January 2016

This paper develops a framework for along-the-channel and through-the-membrane control oriented modeling of polymer electrolyte membrane (PEM) fuel cells. The initial modeling framework is spatially one-dimensional by one-dimensional (1+1D) and is described by unsteady partial differential equations (PDEs). Numerical techniques convert the PDEs and boundary conditions to ordinary differential and algebraic equations that are convenient for state-space modeling. The modeling framework includes two-phase, thermal, and other transient effects. The generality of the modeling framework and its ability to be represented in state-space form facilitate complexity reduction and control-oriented application.
A Low Complexity Gain Scheduling Strategy for Explicit Model Predictive Control of a Diesel Air Path
Authors: Huang Mike , Butts Ken , Kolmanovsky Ilya
Published: January 2016

This paper describes a gain scheduling strategy that can be used in conjunction with explicit Model “Predictive Control (MPC). Traditionally, explicit MPC is not reconfigurable to online model changes. To handle off-nominal plant conditions, a common practice is to design multiple explicit MPC’s which are each valid locally around their respective operating points. This inevitably requires large amounts of memory to store the explicit MPC’s and implementation of switching logic and observers. The gain scheduling strategy presented in this paper bypasses the need to store multiple explicit MPC’s. This is done by multiplying the control signal obtained from the nominal explicit MPC by a gain scheduling matrix such that the plant at off-nominal operating conditions is approximately matched to the nominal plant. This is further accomplished in a manner such that the original control constraints are satisfied. The gain scheduling strategy is demonstrated in simulations on a nonlinear diesel air path model over the New European Drive Cycle (NEDC).
Efficient Lithium-Ion Battery Model Predictive Control Using Differential Flatness-Based Pseudospectral Methods
Authors: Liu Ji , Li Guang , Fathy Hosam K.
Published: January 2016

This paper proposes an efficient nonlinear model predictive control (NMPC) framework to solve nonconvex lithium-ion battery trajectory optimization problems for battery management systems (BMS). It is challenging to solve these problems online due to complexity and nonconvexity. To address these challenges, we combine four established techniques from the control literature. First, we represent the single particle model (SPM) using orthogonal projection techniques. Second, we exploit the differential flatness of Fick’s second law of diffusion to capture all of the dynamics in one electrode using a single scalar trajectory of a “flat output” variable. Third, we optimize the above flat output trajectories using pseudospectral methods. Fourth, we employ the NMPC strategy to solve the battery trajectory optimization problem online. The proposed NMPC framework is demonstrated by solving 2 optimal charging problems accounting for physics-based side reaction constraints and is shown to be twice as computationally efficient as pseudospectral online optimization alone.
Hierarchical Hybrid Predictive Control of an Autonomous Road Vehicle
Authors: Wang Qian , Weiskircher Thomas , Ayalew Beshah
Published: January 2016

This paper presents a hierarchical hybrid predictive control framework for an autonomously controlled road vehicle. At the top, an assigner module is designed as a finite state machine for decision-making. Based on the current information of the controlled vehicle and its environment (obstacles, and lane markings, etc), the assigner selects discrete maneuver states through pre-defined switching rules. The several maneuver states are related to different setups for the underlying model predictive trajectory guidance module. The guidance module uses a reduced-order curvilinear particle motion description of the controlled vehicle and obstacle objects as well as a corresponding description of the reference path, lane and traffic limits. The output of the guidance module interfaces with the lower level controller of the continuous vehicle dynamics. The performance of the proposed framework is demonstrated via simulations of highway-driving scenarios.
Instrumented Walkway for Estimation of the Ankle Impedance in Dorsiflexion-Plantarflexion and Inversion-Eversion During Standing and Walking
Authors: Ficanha Evandro M. , Ribeiro Guilherme , Rastgaar Aagaah Mohammad
Published: January 2016

This paper describes in detail the fabrication of an instrumented walkway for estimation of the ankle mechanical impedance in both dorsiflexion-plantarflexion (DP) and in inversion-eversion (IE) directions during walking in arbitrary directions and standing. The platform consists of two linear actuators, each capable of generating ±351.3 N peak force that are mechanically coupled to a force plate using Bowden cables. The applied forces cause the force plate to rotate in two degrees of freedom (DOF) and transfer torques to the human ankle to generate DP and IE rotations. The relative rotational motion of the foot with respect to the shin is recorded using a motion capture camera system while the forces applied to the foot are measured with the force plate, from which the torques applied to the ankle are calculated. The analytical methods required for the estimation of the ankle torques, rotations, and impedances are presented. To validate the system, a mockup with known stiffness was used, and it was shown that the developed system was capable of properly estimating the stiffness of the mockup in two DOF with less than 5% error. Also, a preliminary experiment with a human subject in standing position was performed, and the estimated quasi-static impedance of the ankle was estimated at 319 Nm/rad in DP and 119 Nm/rad in IE.
Multi-Objective Optimal Control of Wind Turbines for Speed Regulation and Load Reduction
Authors: Njiri Jackson G. , Söffker Dirk
Published: January 2016

This paper presents a multi-objective control method for regulating speed and reducing structural loads on large wind turbines. Structural loads become more pronounced as the turbine size increases resulting in the need to develop control algorithms to minimize the load in addition to the mainstream objectives of regulating speed and maximizing power extraction in the turbines. To realize the two competing objectives of controlling speed/power and structural load minimization, two control loops are employed. The first loop, collective pitch controller (CPC), is designed to regulate rotor rotation speed by reducing aerodynamic power coefficient in high speed regime. Then a multi-input multi-output (MIMO) controller based on Stochastic Proportional-Integral-Observer is used in the second control loop to fulfill the objective of load reduction of rotor blades. The performance of the proposed control algorithm is evaluated against Proportional-Integral controller (PI-Controller). The results demonstrate that the proposed control method can achieve the objective of reducing structural load without much influence on the speed regulation objective.
Robust Cooperative Adaptive Cruise Control Design for Connected Vehicles
Authors: Trudgen Mark , Mohammadpour Javad
Published: January 2016

In this paper, we design and validate a robust H∞ controller for Cooperative Adaptive Cruise Control (CACC) in connected vehicles. CACC systems take advantage of onboard sensors and wireless technologies working together in order to achieve smaller inter-vehicle following distances, with the overall goal of increasing vehicle throughput on busy highways, and hence serving as a viable approach to reduce traffic congestion. A group of connected vehicles equipped with CACC technology must also ensure what is known as string stability. This requirement effectively dictates that disturbances should be attenuated as they propagate along the platoon of following vehicles. In order to guarantee string stability and to cope with the uncertainties seen in the vehicle model used for a model-based CACC, we propose to design and implement a robust H∞ controller. Loop shaping design methodology is used in this paper to achieve desired tracking characteristics in the presence of competing string stability, robustness and performance requirements. We then employ model reduction techniques to reduce the order of the controller and finally implement the reduced-order controller on a simulation model demonstrating the robust properties of the closed-loop system.
Thermal Model of Fuse Dynamics for Simulation Under Intermittent DC Faults
Authors: Hegde Bharatkumar , Midlam-Mohler Shawn , Tulpule Punit J.
Published: January 2016

The paper presents a practical approach to automotive fuse simulations. A fuse model was developed using only the fuse blow curves provided by the fuse manufacturer. The parameters of the fuse model were determined by minimizing the squared error between the fuse blow curves of the model and manufacturer’s datasheet. The fuse model presented captured the behavior of the fuse during normal and intermittent DC faults. It is demonstrated that the model developed in this research provides better thermal model than available methods. The motivation for the article has been described in the introduction.