bluuebunny/crossref_metadata_2025_split huggingface dataset:
A mixed PI/VI design method for nonlinear H∞ Control
Authors: Liu Lijun , Zhu Chunhui , Wei Fang , Yu Zhen 
Published: September 2019

SummaryThis paper proposes a new mixed policy iteration and value iteration (PI/VI) design method for nonlinear H∞ control based on the theories of polynomial optimization and Lasserre's hierarchy. The design of a mixed PI/VI controller can be carried out in four steps: firstly, initialize design parameters and expand nonlinear system matrices; secondly, obtain a polynomial matrix inequality for policy improvement; thirdly, obtain the Lasserre's hierarchy of a global polynomial optimization problem for value improvement; fourthly, perform the mixed PI/VI algorithm to approximate the optimal nonlinear H∞ control law. The novelty of this work lies in that the problem of designing a nonlinear H∞ controller is translated into a polynomial global optimization problem, which can be solved by Lasserre's hierarchy directly, and then, the mixed PI/VI algorithm is presented to approximate the optimal nonlinear H∞ control law by updating global optimizers iteratively. The main results of this paper consist of the mixed PI/VI algorithm and the related three theorems, which guarantee robust stability and performance of the closed‐loop nonlinear system. Numerical simulations show that the mixed PI/VI algorithm converges very fast and achieves good robust stability and performance in transient behavior, disturbance rejection, and enlarging the domain of attraction of the close‐loop system.
Regioselective Synthesis of Carbazole‐Grafted Dispirothiapyrrolizine Derivatives via 1,3‐Dipolar Cycloaddition Strategy
Authors: Murali Karunanidhi , Sparkes Hazel A. , Prasad Karnam Jayarampillai Rajendra 
Published: September 2019

AbstractA library of dispirooxindole‐thiapyrrolizine derivatives have been prepared via 1,3‐dipolar cycloaddition of azomethine ylide, generated in situ from the reaction of isatin and thiaproline with a series of 2‐arylidene/heteroarylidene‐2,3,4,9‐tetrahydrocarbazol‐1‐ones. Moderate to good yields were obtained for these reactions and also for spiro compounds of acenaphthenequinone obtained using the same optimized reaction condition. The structures of the spiro compounds were established by FTIR, 1H NMR, 13C NMR and elemental analysis. The regio‐ and stereo‐chemistry of the spiranic adducts were ascertained by single crystal X‐ray diffraction studies.
Identifying general trends and patterns in complex systems research: An overview of theoretical and practical implications
Authors: Preiser Rika 
Published: September 2019

AbstractResearch on complex systems is becoming more prolific, and there is a need to provide some point of orientation to researchers and practitioners that are drawing on the body of literature that informs the field of complexity research. In this paper, I aim to give an overview of the development of the field and offer some overarching trends and patterns that are recognizable in research on complex systems. The paper then draws on the work to provide six organizing principles of complex systems to inform practical implications and methods for studying and understanding complex systems.
Optimum design of tuned mass dampers for different earthquake ground motion parameters and models
Authors: Greco Rita , Morga Mariantonietta 
Published: September 2019

SummaryTuned mass dampers are frequently used for passive control of vibrations in civil structures subject to seismic and wind actions. Their efficiency depends on selection of their mechanical properties in relation to main system and excitation characteristics. This paper proposes an optimum design strategy of single tuned mass dampers to control vibrations of principal mode of structures excited by earthquake ground motion. The main purpose of the paper is to investigate the influence of the time modulation of earthquake excitation upon the optimal tuned mass dampers design parameters: frequency and damping ratio. The study is based on numerical analyses carried out with different stochastic models for earthquakes: a simple filtered white noise model and two time modulated filtered white noise models. The numerical analyses are carried out to solve an optimization problem with a performance index defined by the reduction of the standard deviation of either the structure displacement or its inertial acceleration as objective function. To complete the work, the influence of the bandwidth excitation over the values of the optimal tuned mass damper parameters is investigated, as well the optimum mass ratio and the structure frequency. The results of the numeral analyses carried out infer that the earthquake excitation characteristics, including its modulation in time domain, highly affect the optimum tuned mass damper design parameters values.
Wind farm generation forecast and optimal maintenance schedule model
Authors: Pelajo Jonas C. , Brandão Luiz E.T. , Gomes Leonardo L. , Klotzle Marcelo C. 
Published: September 2019

AbstractWind farms must periodically take their turbines offline in order to perform scheduled maintenance repairs. Given that these interruptions impact energy generation and that under Power Purchase Agreements productions shortfalls must be replaced by energy purchases in the spot market, the optimal time to begin maintenance work in a wind farm is a function of both the expected wind speeds and electricity spot prices. In this article, we develop a model to determine the optimal maintenance schedule of a wind farm based on forecasted wind speeds and energy prices. We analyze a window of opportunity in the most likely period of the year and perform weekly updates of expected wind speeds and energy price forecasts. Wind speeds are forecasted with an ARMAX model, where monthly dummies are used as exogenous variables to capture the seasonality of wind speeds, while spot prices are simulated under a standard dual stochastic programing model. The decision to defer maintenance to a future date is modeled in a probabilistic model and also under the real options approach. We test these models with actual data from a wind farm in the Brazilian Northeast and provide comparisons with current practice in order to determine the benefits of the model. The results suggest that this model may provide advantages over a stopping decision that randomly chooses a week to begin maintenance within the opportunity window and is close to the optimal stopping date considering perfect information on future wind speeds and electricity prices.
The Importance of Spatial Data to Open-Access National Archaeological Databases and the Development of Paleodemography Research
Authors: Robinson Erick , Nicholson Christopher , Kelly Robert L. 
Published: September 2019

AbstractWith generous support from the National Science Foundation, we have spent the past four years developing an archaeological radiocarbon database for the United States. Here, we highlight the importance of spatial data for open-access, national-scale archaeological databases and the development of paleodemography research. We propose a new method for analyzing radiocarbon time series in the context of paleoclimate models. This method forces us to confront one of the central challenges to realizing the full potential of national-scale databases: the quality of the spatial data accompanying radiocarbon dates. We seek to open a national discussion on the use of spatial data in open-source archaeological databases.
Extension of classical stability theory to viscous planar wall-bounded shear flows
Authors: Lee Harry , Wang Shixiao 
Published: September 2019

A viscous extension of Arnold’s inviscid theory for planar parallel non-inflectional shear flows is developed and a viscous Arnold’s identity is obtained. Special forms of the viscous Arnold’s identity have been revealed that are closely related to the perturbation’s enstrophy identity derived by Synge (Proceedings of the Fifth International Congress for Applied Mechanics, 1938, pp. 326–332, John Wiley) (see also Fraternaleet al.,Phys. Rev. E, vol. 97, 2018, 063102). Firstly, an alternative derivation of the perturbation’s enstrophy identity for strictly parallel shear flows is acquired based on the viscous Arnold’s identity. The alternative derivation induces a weight function. Thereby, a novel weighted perturbation’s enstrophy identity is established, which extends the previously known enstrophy identity to include general streamwise translation-invariant shear flows. Finally, the validity of the enstrophy identity for parallel shear flows is rigorously examined and established under global nonlinear dynamics imposed with two classes of wall boundary conditions. As an application of the enstrophy identity, we quantitatively investigate the mechanism of linear instability/stability within the normal modal framework. The investigation reveals a subtle interaction between a critical layer and its adjacent boundary layer, which determines the stability nature of the disturbance. As an implementation of the relaxed wall boundary conditions imposed for the enstrophy identity, a control scheme is proposed that transitions the wall settings from the no-slip condition to the free-slip condition, through which a flow is stabilized quickly in an early stage of the transition.
Radiocarbon Dating and the Protection of Cultural Heritage
Authors: Hajdas Irka , Jull A J Timothy , Huysecom Eric , Mayor Anne , Renold Marc-André , Synal Hans-Arno , Hatté Christine , Hong Wan , Chivall David , Beck Lucile , Liccioli Lucia , Fedi Mariaelena , Friedrich Ronny , Maspero Francesco , Sava Tiberiu 
Published: September 2019

ABSTRACTThe modern antiquities market uses radiocarbon (14C) dating to screen for forged objects. Although this fact shows the potential and power of the method, the circumstances where it is applied can be questionable and call for our attention. Here we present an outline of a call to radiocarbon laboratories for due diligence and best practice approaches to the analysis of antique objects requested by non-research clients.
The Ultra Vires Doctrine in a Constitutional Setting: Still the Central Principle of Administrative Law
Authors: Elliott Mark 
Published: September 2019

There is currently a good deal of disagreement concerning the constitutional justification for judicial review in English law. The ultra vires doctrine holds that review is simply a function of legislative intention. In contrast, a number of commentators argue that administrative law is a body of judge-made common law which is unrelated to the will of Parliament. The truth lies somewhere between these two poles.The traditional ultra vires doctrine is unsatisfactory because, inter alia, it is unrealistic to assert that judicial review constitutes nothing more than the implementation of legislative intention. However, the attempt of some commentators to exclude intention from the justification for review is equally deficient since this is an affront to the sovereignty of Parliament. By locating the interpretative methodology of ultra vires within its proper constitutional setting and by recognising the importance of the rule of law to the process of statutory construction, it is possible to articulate an explanation of judicial review which is consistent with Parliament's legislative supremacy while avoiding the shortcomings of the traditional ultra vires principle (notably its inability satisfactorily to explain the derivation of the grounds of review; the courts' treatment of ouster clauses; the development of administrative law across time, and the extension of judicial review to non-statutory powers).
LINGUISTIC EVIDENCE AND HISTORICAL RECONSTRUCTION
Authors: VANSINA JAN 
Published: September 2019

A Green Place, a Good Place: Agrarian Change, Gender and Social Identity in the
Great Lakes Region to the Fifteenth Century. By David Lee
Schoenbrun. Portsmouth, NH: Heinemann: Oxford: James Currey, 1998. Pp. xiv+301.
£40 (ISBN 0-325-00041-7); £15.95, paperback (ISBN 0-325-00040-9).An African Classical Age: Eastern and Southern Africa in World History, 1000 B.C.
to A.D. 400. By Christopher Ehret. Charlottesville: University Press of
Virginia; Oxford: James Currey, 1998. Pp. xvii+354. £35 (ISBN 0-8139-1814-6).Recently several historical reconstructions based on linguistic evidence and dealing
with ancient times have been published in African history. In 1998 alone there are
the two books reviewed here as well as a major work by Gerda Rossel. Linguistic
sources contribute much to the recovery of aspects of the past, which would
otherwise remain out of reach, and the standard methodologies of historical
linguistics are well known to readers of this journal. Yet in practice many
historians remain all too often disconcerted by such studies because they have
great difficulty in evaluating them: i.e. in linking assertions made to the evidence
provided and so to establish the credibility of such statements. This is not just
because many historians are unfamiliar with linguistic evidence but because all the
evidence necessary for evaluation is usually not available in the work studied, and
often enough authors do not clearly indicate where it can be found. Indeed
sometimes it is not available at all. In such cases one has to take the statements
made by the authors on faith: one believes the author or not. That is clearly
unacceptable. For is it not a fundamental rule in history writing that assertions
must be substantiated and hence evidence must be cited or provided? Any work
without substantiation cannot be considered to be a work of history at all.
The reduction and elimination of a closed separation region by free-stream turbulence
Authors: KALTER M. , FERNHOLZ H. H. 
Published: September 2019

This paper is an extension of an experimental investigation by Alving & Fernholz
(1996). In the present experiments the effects of free-stream turbulence were investigated
on a boundary layer with an adverse pressure gradient and a closed reverse-flow
region. By adding free-stream turbulence the mean reverse-flow region was shortened
or completely eliminated and this was used to control the size of the separation
bubble. The turbulence intensity was varied between 0.2% and 6% using upstream
grids while the turbulence length scale was on the order of the boundary layer thickness.
Mean and fluctuating velocities as well as spectra were measured by means of
hot-wire and laser-Doppler anemometry and wall shear stress by wall pulsed-wire
and wall hot-wire probes.Free-stream turbulence had a small effect on the boundary layer in the mild
adverse-pressure-gradient region but in the vicinity of separation and along the
reverse-flow region mean velocity profiles, skin friction and turbulence structure were
strongly affected. Downstream of the mean or instantaneous reverse-flow regions
highly disturbed boundary layers developed in a nominally zero pressure gradient
and converged to a similar turbulence structure in all three cases at the end of the test
section. This state was, however, still very different from that in a canonical boundary
layer.
ASSESSMENT OF NEW CARDIOVASCULAR DRUGS
Authors: Wieringa Nicolien F. , Denig Petra , de Graeff Pieter A. , Vos Rein 
Published: September 2019

Objectives: To study considerations used by professional and academic leaders to assess the position of new cardiovascular drugs in the therapeutic regimen in relationship to professional characteristics and the level of prescribing.Methods: Interviews with 39 internists, cardiologists, general practitioners, and hospital pharmacists about considerations regarding the therapeutic position and prescribing of a new cardiovascular drug (losartan or atorvastatin) and professional characteristics. Considerations were classified according to Rogers' characteristics of an innovation, i.e., referring to the drug's relative advantage, compatibility, or complexity. Proportions of respondents mentioning advantageous, comparable, and/or disadvantageous characteristics were used to construct patterns to analyze an overall evaluation of the drugs in relation to professional characteristics and level of prescribing.Results: The majority of considerations referred to the degree of relative advantage, but different subjects were emphasized for both drugs. Overall patterns of evaluation were generally intermediate and negative. The respondents' profession, mentioning commercial sources of information and self-qualification as a (moderately) early adopter of new drugs differentiated the overall evaluation of the drugs, in contrast to expertness and academic affiliation. The level of prescribing differentiated the overall evaluation only in the case of losartan.Conclusions: These professional and academic leaders critically evaluated the claims when assessing the position of the drugs in the therapeutic regimen but did not show consensus in their considerations. Accepted principles for prescribing were considered when assessing the therapeutic position of the drugs but resulted in varied tendencies for prescribing.
PHARMACOECONOMIC COMPONENT OF A CLINICAL TRIAL CONDUCTED IN LATIN AMERICA
Authors: Reinharz Daniel , Saldaña Victor Raúl Zurita , Follador Wilson , Asche Carl 
Published: September 2019

Background: Although pharmacoeconomic studies constitute a valuable tool for better managing drug consumption, the conditions under which such studies would be performed in Latin American countries have not been explored.Objectives: The aim of this paper is to evaluate the potential advantages of and pitfalls in doing pharmacoeconomic research in Latin America and to propose avenues to facilitate the development of this field in the region.Methods: The Canadian guidelines for the economic evaluation of pharmaceuticals served as a structured framework to assess, both prospectively and retrospectively, the conditions under which the pharmacoeconomic component of a clinical trial held in Mexico and Brazil would be and actually was conducted.Results: The conditions under which pharmacoeconomic evaluations are conducted must be improved if studies are to contribute to the better management of scarce resources across the entire health care system.Conclusions: The creation of a public funding agency, the reappraisal of administrative data as a management tool in both the public and the private sectors, and the establishment of national guidelines should be considered within the framework of reforms aimed at allowing healthcare systems to meet their objectives of efficiency and equity.
ASSESSMENT OF THE TREATMENT COSTS OF EXTRACORPOREAL SHOCK WAVE THERAPY VERSUS SURGICAL TREATMENT FOR SHOULDER DISEASES
Authors: Haake Michael , Rautmann Michael , Wirth Thomas 
Published: September 2019

Objective: To determine the actual costs of extracorporeal shock wave therapy (ESWT) in patients with tendinitis of the supraspinatus muscle.Methods: A comparison of the costs of surgical treatment versus the costs for ESWT was made. The total accrued costs were determined 12 weeks after intervention, using a sample group of 60 patients with calcifying or noncalcifying tendinitis of the supraspinatus muscle.Results: The costs per case ranged from EUR 2,700 to EUR 4,300 per patient for ESWT and from EUR 13,400 to EUR 23,450 for surgical treatment, dependent on the method of calculation. Approximately 65% of the per-patient cost is attributable to productivity losses in the workplace.Conclusions: In comparable short-term results, costs for operative treatment are 5–7 times higher than for ESWT. The greater trauma caused by an operative procedure leads to patients being off work for a longer period and thus a correspondingly higher social economic burden.
ECONOMIC EVALUATION OF COCHLEAR IMPLANT
Authors: Carter Rob , Hailey David 
Published: September 2019

Objectives: To examine the economic efficiency of current cochlear implant technology under Australian conditions in profoundly deaf adults, partially deafened adults, and childrenMethods:> Cost—utility study, with weights based on judgments from persons experienced with the technology, and cost data from Australian sources.Results: Quality—of— improvements due to functional consequences of hearing improvement were greater than those due to amelioration of hearing disability. Costs in Australian dollars per QALY (15—year assessment) ranged from $5,070—$11,100 for children, $11,790—$38,150 for profoundly deaf adults, and $14,410—$41,000 for partially deaf adults.Conclusions: Results suggest cochlear implantation is acceptable value for money when compared with other health programs to which resources are committed in Australia.
THE COST-EFFECTIVENESS OF PROPHYLAXIS FOR MYCOBACTERIUM AVIUM
COMPLEX IN AIDS
Authors: Scharfstein Julie A. , Paltiel A. David , Weinstein Milton C. , Seage George R. , Losina Elena , Craven Donald E. , Freedberg Kenneth A. 
Published: September 2019

Objective: To develop a simulation model to project costs, life
expectancy, and cost-effectiveness in discounted dollars per quality-adjusted
life-year (QALY) saved for clinical strategies to prevent Mycobacterium
avium complex (MAC) in patients with AIDS.Methods: We used natural history data from the Multicenter AIDS
Cohort Study, efficacy and toxicity data from randomized clinical trials, and
cost data from the AIDS Cost and Services Utilization Survey. The model
permits timing of prophylaxis to be stratified by CD4 count (201–300,
101–200, 51–100, and ≤ 50/mm3), and allows
combinations of prophylaxis, crossover to second- and third-line agents for
toxicity, and consideration of adherence, resistance, and quality of life.Results: The model projects that the average HIV-infected patient
with a beginning CD4 count between 201 and 300/mm3 has total
lifetime costs of approximately $43,150 and a quality-adjusted life expectancy
of 42.35 months. If azithromycin prophylaxis for M. avium complex is
begun after the CD4 declines to 50/mm3, costs and
quality-adjusted survival increase to approximately $44,040 and 42.78 months,
respectively, for an incremental cost-effectiveness ratio of $25,000/QALY
compared with no M. avium complex prophylaxis. Other prophylaxis
options (i.e., rifabutin, clarithromycin, and combination therapies) either
cost more but offer shorter survival, or have cost-effectiveness ratios above
$260,000/QALY. Sensitivity analysis reveals that, for reasonable
assumptions about quality of life, risk of infection, prophylaxis cost,
adherence, and resistance, azithromycin remains the most cost-effective
prophylaxis option.Conclusions: Azithromycin prophylaxis, begun after the CD4 count
has declined to 50/mm3, is the most cost-effective M. avium complex prophylaxis strategy. Consistent with new United States Public
Health Service guidelines, it should be the first-line prophylaxis option.