bluuebunny/crossref_metadata_2025_split huggingface dataset:
A study of an elbow mechanism generated by a conical cutter
Authors: Yang S-C 
Published: July 2007

This paper presents a method for determining the mathematical model of an elbow mechanism with a convex tooth and a concave tooth. Based on this method, the mathematical model presents the meshing principles of a conical cutter meshed with a tooth that is either convex or concave. Using the developed mathematical models and the tooth contact analysis, kinematic errors are investigated according to the obtained geometric modelling of the designed gear meshing when assembly errors are present. The influence of misalignment on kinematic errors has been investigated. The goal of the current study is to investigate von-Mises stress for three teeth contact pairs. A structural load is assumed to act on a gear of the proposed mechanism. The von-Mises of the proposed gear is determined. The conical cutter used in the design and manufacture of the convex and concave gear is shown. For example, the proposed mechanism with a transmission ratio of 3:2 was determined with the aid of the proposed mathematical model. Using rapid prototyping and manufacturing technology, an elbow mechanism with a convex gear, a concave gear and a frame was designed. The RP primitives provide an actual full-size physical model that can be analysed and used for further development. Results from these mathematical models are applicable to the design of an elbow mechanism.
Molecular Structures of the Coloring Species of a Leuco Dye with Phenolic Color Developers
Authors: Sekiguchi Yumiko , Takayama Satoshi , Gotanda Takeshi , Sano Kenji 
Published: July 2007

Abstract
We have isolated the coloring species of a leuco dye colored by three phenolic color developers and have revealed their molecular structures by X-ray crystallographic analysis for the first time: one leuco dye molecule combined with one developer molecule by the hydrogen bonds between the carboxylate anion of a leuco dye and the OH groups of a color developer.
Chiral Effects on Magnetic Properties for Chiral and Racemic WV–CuII Prussian Blue Analogues
Authors: Higashikawa Hiroyuki , Okuda Kazuki , Kishine Jun-ichiro , Masuhara Naoji , Inoue Katsuya 
Published: July 2007

Abstract
The chiral and racemic 2-D antiferromagnets based on a cyano-bridged WV–CuII compound are constructed. Both compounds are similar crystal structure, but some differences in magnetic properties appear owing to the existence of the Dzyaloshinsky–Moriya (DM) interactions, that is generated by crystal chirality.
Association of FLT3 Polymorphisms With Low BMD and Risk of Osteoporotic Fracture in Postmenopausal Women
Authors: Koh Jung-Min , Oh Bermseok , Lee Jong-Young , Lee Jong-Keuk , Kimm Kuchan , Park Byung Lae , Shin Hyoung Doo , Lee Il-Kwon , Kim Hyeoung-Joon , Hong Jung-Min , Kim Tae-Ho , Kim Ghi Su , Kim Shin-Yoon , Park Eui Kyun 
Published: July 2007

Abstract
The genetic effects of FLT3 polymorphisms on BMD and fracture risk in postmenopausal women were studied. We found that FLT3+13348C&gt;T polymorphism and haplotype 2 were significantly associated with low BMD and high risk of fracture.
Introduction: FMS-related tyrosine kinase 3 (FLT3) has been shown to play a critical role in the development of myelolymphoid progenitors and in the development of osteoclasts, but any possible genetic effect of FLT3 on bone metabolism has not been studied.
Materials and Methods: To study a possible genetic effect of FLT3, we directly sequenced the FLT3 gene in 24 Korean individuals and identified 23 sequence variants. Seven polymorphisms were selected and genotyped in Korean postmenopausal women (n = 946).
Results: We found that FLT3+13348C&gt;T was associated with low BMD at the lumbar spine (p = 0.04) and femoral neck (p = 0.04). Haplotype analysis revealed that FLT3-ht2 (TTCTT) containing the rare allele in the +13348 position also showed significant association with low BMD in the lumbar spine (p = 0.04) and femoral neck (p = 0.05). Consistent with these results, the FLT3+13348C&gt;T polymorphism and FLT3-ht2 were also significantly associated with high risk of fracture in the vertebrae (OR = 1.44–1.58; p = 0.03–0.04 and OR = 1.45–1.59; p = 0.02–0.03, respectively) and in any sites (OR = 1.34–1.81; p = 0.02–0.03 and OR = 1.34–1.81; p = 0.02–0.03, respectively).
Conclusions: These results suggest that FLT3 polymorphisms play a role in determination of BMD and subsequent fractures in postmenopausal women.
Genetic Effects on Bone Loss in Peri- and Postmenopausal Women: A Longitudinal Twin Study
Authors: Makovey Joanna , Nguyen Tuan V , Naganathan Vasi , Wark John D , Sambrook Philip N 
Published: July 2007

Abstract
This longitudinal twin study was designed to assess the heritability of bone loss in peri- and postmenopausal women. A sample of 724 female twins was studied. Baseline and repeat BMD measurements were performed. Results of genetic model-fitting analysis indicated genetic effects on bone loss account for ∼40% of the between-individual variation in bone loss at the lumbar spine, forearm, and whole body.
Introduction: BMD and bone loss are important predictors of fracture risk. Although the heritability of peak BMD is well documented, it is not clear whether bone loss is also under genetic regulation. This study was designed to assess the heritability of bone loss in peri- and postmenopausal women.
Materials and Methods: A sample of 724 female twins (177 monozygotic [MZ] and 185 dizygotic [DZ] pairs), 45–82 yr of age, was studied. Each individual had baseline BMD measurements at the lumbar spine, hip, forearm, and total body by DXA and at least one repeat measure, on average 4.9 yr later. Change in BMD (ΔBMD) was expressed as percent of gain or loss per year. Intraclass correlation coefficients for ΔBMD were calculated for MZ and DZ pairs. Genetic model-fitting analysis was conducted to partition the total variance of ΔBMD into three components: genetic (G), common environment (C), and specific environment, including measurement error (E). The index of heritability was estimated as the ratio of genetic variance over total variance.
Results: The mean annual ΔBMD was –0.37 ± 1.43% (SD) per year at the lumbar spine, −0.27 ± 1.32% at the total hip, −0.77 ± 1.66% at the total forearm, −0.36 ± 1.56% at the femoral neck, and −0.16 ± 0.81% at the whole body. Intraclass correlation coefficients were significantly higher in MZ than in DZ twins for all studied parameters, except at the hip sites. Results of genetic model-fitting analysis indicated that the indices of heritability for ΔBMD were 0.38, 0.49, and 0.44 for the lumbar spine, total forearm, and whole body, respectively. However, the genetic effect on ΔBMD at all hip sites was not significant.
Conclusions: These data suggest that, although genetic effects on bone loss with aging are less pronounced than on peak bone mass, they still account for ∼40% of the between-individual variation in bone loss for the lumbar spine, total forearm, and whole body in peri- and postmenopausal women. These findings are relevant for studies aimed at identification of genes that are involved in the regulation of bone loss.
A revised multi-Fickian moisture transport model to describe non-Fickian effects in wood
Authors: Frandsen Henrik Lund , Damkilde Lars , Svensson Staffan 
Published: July 2007

Abstract
This paper presents a study and a refinement of the sorption rate model in a so-called multi-Fickian or multi-phase model. This type of model describes the complex moisture transport system in wood, which consists of separate water vapor and bound-water diffusion interacting through sorption. At high relative humidities, the effect of this complex moisture transport system becomes apparent, and since a single Fickian diffusion equation fails to model the behavior, it has been referred to as non-Fickian or anomalous behavior. At low relative humidities, slow bound-water transport and fast sorption allow a simplification of the system to be modeled by a single Fickian diffusion equation. To determine the response of the system, the sorption rate model is essential. Here the function modeling the moisture-dependent adsorption rate is investigated based on existing experiments on thin wood specimens. In these specimens diffusion is shown to be negligible, allowing a separate study of the adsorption rate. The desorption rate has been observed to be slower at higher relative humidities as well, and an expression analogous to the adsorption rate model is proposed. Furthermore, the boundary conditions for the model are discussed, since discrepancies from corresponding models of moisture transport in paper products have been found.
A fast RLS transversal filter for adaptive linear phase filtering
Authors: Slock Dirk T. M. , Kailath Thomas 
Published: July 2007

AbstractA fast transversal filter algorithm is presented for the adaptive recursive least‐squares design of filters with linear phase. Connections with a popular method of spectrum estimation are explored. The algorithm is derived in a new framework, for the prewindowed given data case. Exact and soft‐constraint initialization are discussed and an improved rescue procedure is proposed. Data sequence weighting is introduced to allow for arbitrarily time‐varying weighting strategies, facilitating the tracking of arbitrarily non‐stationary phenomena.
Robust model reference adaptive control for multivariable plants
Authors: Tao G. , Ioannou P. A. 
Published: July 2007

AbstractA complete procedure for generating and analysing robust model reference adaptive control schemes for multivariable plants is developed. The procedure consists of two parts: the first part involves the characterization of the integral structure of the modelled part of the plant, and the associated parametrization of the controller structure; and the second part involves the development of a general robust adaptive law for adjusting the controller parameters so that the closed‐loop plant is globally stable despite the presence of unmodelled dynamics and bounded disturbances. The use of dominantly rich signals for improving convergence and the bounds for the tracking and parameter error is also analysed.
Feedback linearization in the presence of uncertainties
Authors: Sastry S. S. , Kokotovic P. V. 
Published: July 2007

AbstractAfter a brief review of feedback linearization, several approaches to the problem of parametric uncertainty are outlined, and the adaptive approach to both SISO and MIMO plants is discussed in detail. Based on experience with adaptive control of linear plants, two parameter update laws are chosen for nonlinear plants according to their relative degrees. The simpler of the two adaptive laws is applicable to plants with relative degree one. For plants with higher relative degree the adaptive scheme is more complex, but a simple update law can still be employed in the special case when the state diffeomorphism, required for linearization, does not depend on uncertain parameters. The simpler adaptive scheme is shown to be robust with respect to unmodelled dynamics.
Adaptive control for time‐varying systems: A combination of Martingale and Markov chain techniques
Authors: Guo Lei , Meyn Sean P. 
Published: July 2007

AbstractAdaptive control problems of a first‐order randomly time‐varying stochastic system are considered. A class of adaptive controllers based on the Kalman filter is introduced and is analysed using a combination of martingale and Markov chain techniques. It is shown that both the expected value and sample path averages of the square of the output of the closed‐loop system remain bounded and that the long‐run cost is a continuous functional of the parameters of the controller and the distribution of the disturbance process. These results hold even when the Gaussian assumption used in previous papers is removed and the a priori estimate of the noise variance is incorrect.
Applications of the passive systems approach to the stability analysis of adaptive controllers for robot manipulators
Authors: Landau I. D. , Horowitz R. 
Published: July 2007

AbstractUtilizing the fact that a manipulator composed of rigid links is a passive system, an approach based on the properties of interconnected passive systems is proposed for the analysis and synthesis of fixed and adaptive controllers for robot manipulators. This approach clarifies the rationale behind the various fixed and adaptive control laws synthesized using Lyapunov functions and provides new adaptation algorithms.
Fourier series expansions of noisy signals — consistent estimation of the whole spectrum
Authors: Rafajłsowicz Ewaryst 
Published: July 2007

AbstractIn this note the problem of estimating the Fourier series coefficients of a deterministic signal measured in a noise is discussed. Firstly, it is shown that if random errors are not taken into account, then the mean square error between the true spectrum and its commonly used estimator is infinite. The method proposed for overcoming this difficulty is based on multiplying the estimates by the geometric sequence. It is shown that if this sequence depends on the number of observations and is appropriately chosen, then consistent estimation of the whole spectrum is possible. The method introduces a bias which is shown to be asymptotically vanishing. For smooth signals an upper bound for the bias is also derived.
A real‐time implementation of an iir adaptive line enhancer
Authors: Vishwanath T. G. , Campbell D. R. , Moir T. J. 
Published: July 2007

AbstractAn IIR adaptive line enhancer (ALE) based on the innovations model is implemented in real time using a TMS32010 microprocessor. Results are presented to illustrate the performance of the ALE under different signal‐to‐noise (SNR) ratios.
MAR: A multiprocessor adaptive regulator
Authors: Bonivento Claudio , Melchiorri Claudio 
Published: July 2007

AbstractThe present state of the multiprocessor adaptive regulator (MAR) project, a prototype controller developed at the University of Bologna, is presented. The controller is designed in a distributed environment, based on the following components: a VME bus hardware, MC68000 CPU boards and DRM, a distributed real‐time operating system. The project is carried out in the framework of a research programme between DEIS and Philips Italia, I&E Division. MAR represents a significant evolution of previous experiences at DEIS in the implementation of self‐tuning regulators, developed both on 8‐bit and 16‐bit monoprocessor configurations. The prototype software is supported by the concept of a‘software machine’(SOMA) running on a‘hardware machine’(HAMA) typical of the DRM system. Particular attention is given to the definition of a user‐friendly interface and to the development of supervisory features in order to obtain well‐conditioned and robust performances. These features mainly deal with controller start‐up, parameter estimator wind‐up and actuator wind‐up. Two adaptive control policies are presently available, i.e. pole‐zero placement and minimum variance control. Experiments snowing the implemented functions and results obtained from different SOMA distributions are presented and discussed.
Further evaluation of partial, state model reference adaptive design
Authors: M'Saad M. , Landau I. D. , Samaan M. 
Published: July 2007

AbstractThis paper is a follow up to Reference 1. It presents further evaluation of the partial state model reference adaptive control approach proposed in Reference 2. This evaluation involves suitable benchmark examples that have been proposed in Reference 3 to illustrate the essence of today's adaptive control design techniques. Particular emphasis is put on the ability of the considered adaptive controller to accommodate state disturbances, sensor noise and unmodelled dynamics.
Illustration of an integrated approach to adaptive control
Authors: Goodwin Graham C. , Ninness Brett , Cockerell Ross , Salgado Mario 
Published: July 2007

AbstractThis paper illustrates the application of an integrated approach to adaptive control by reference to the case study problem proposed by Masten and Cohen. The underlying philosophy of our approach includes the integration of robust and adaptive control and the unification of continuous and discrete systems theory. A feature of the examples presented below is that they have been run in real time using a general‐purpose adaptive control toolbox.
An adaptive filter for time‐varying‐parameter models
Authors: Abutaleb A. , Papaioannou M. 
Published: July 2007

AbstractA non‐linear adaptive filter is introduced and applied to the classical problem of estimating time‐varying‐parameter linear regression models with unknown error variances and a time‐varying transition matrix. The filter is basically a new result in what is known as Sridhar filtering theory. In deriving the filter, which we call the ‘Pontryagin filter’, the Pontryagin minimum principle and the method of invariant imbedding were used. The properties (bias and consistency) of the estimates of the time‐varying parameters are then established.
Factorizations that relax the positive real condition in continuous‐time and fast‐sampled ELS schemes
Authors: Krishnamurthy Vikram , Wahlberg Bo , Moore John B. 
Published: July 2007

AbstractThis paper proposes extended least‐squares (ELS) for ARMAX model identification of continuous‐time and certain discrete‐time systems. The schemes have a relaxed strictly positive real (SPR) condition for global convergence. The relaxed SPR scheme is achieved by introducing overparametrization and prefiltering but without introducing ill‐conditioning. The schemes presented are the first such proposed for continuous‐time systems.The concepts developed in continuous time carry through to fast‐sampled continuous‐time systems and associated discrete‐time ELS algorithms. For such situations, in comparison with previously proposed discrete‐time schemes, the degree of overparametrization required in the proposed scheme of this paper is significantly lower. The reduction is achieved by using more suitable prefiltering and overparametrization techniques than previously proposed.We also establish the persistence of excitation (PE) of the regression vectors in the proposed ELS schemes to assure strong consistency, obtain convergence rates and provide robustness to unmodelled dynamics. To prove the PE of continuous‐time regression vectors, we develop output reachability characterization for MIMO linear continuous‐time systems.
Computed torque control via a non‐linear observer
Authors: Canudas Wit C. De , Åström K. J. , Fixot N. 
Published: July 2007

AbstractHigh‐precision measurements of joint displacements are available on robot manipulators. In contrast, the velocity measurements obtained through tachometers are in many cases contaminated by noise. It is therefore economically and technically interesting to investigate the possibility of accurately estimating the speed from direct available measurements such as the angular positions. This paper proposes a ‘smooth non‐linear observer’ (i.e. an observer with ‘smooth’ or ‘differentiable’ gains) and a modified computed torque law which is a function of estimated velocities and measurement positions for rigid industrial robot manipulators. We derive local conditions for asymptotic stability of the closed‐loop system.
Robot non‐linearity bounds evaluation techniques for robust control
Authors: Grimm Wolfgang M. 
Published: July 2007

AbstractRobust controller design approaches for non‐linear control systems usually require the evaluation of upper bounds on non‐linear quantities of the process for the robustness analysis. The conservatism and usefulness of robustness criteria are determined by the accuracy of the robustness bounds. This contribution deals with the robust control of robot manipulators and presents generally applicable evaluation techniques for bounds on robot manipulator non‐linearities which may be remnants of an incomplete non‐linear decoupling or feedback linearization. These bounds can be used to verify several robust stability criteria for the control of rigid and elastic joint robots. Apparently, these bounds give insight to the strength and significance of non‐linear couplings and may be used to judge whether complicated model‐based control laws should be preferred rather than simple linear controllers.
Multivariable controller design in an adaptive control scheme
Authors: Pang Grantham K. H. 
Published: July 2007

AbstractA multivariable control system design approach in the frequency domain is presented. The issue of control system redesign in an adaptive control scheme is discussed. Expert system techniques have been used for the automated design of controllers for multivariable systems. Design knowledge has been represented using rules, facts and objects. The design process consists of a sequence of operations obtained by heuristics and experience in the the design techniques. An automated design session of a multivariable plant using the expert system demonstrates that the expert system appears to work well in its prototype implementation.
Optical adaptive signal processing: An appraisal
Authors: Bitmead Robert R. , Johnson C. Richard , Pollock Clifford R. 
Published: July 2007

AbstractPotential areas of development in optically based adaptive signal processing are considered together with an assessment of current technological directions. The rapid adoption of superhigh‐throughput lightwave communications media and systems suggests that fully optical signal processing would be very desirable to take advantage of the speed. The broad conclusion of this analysis is that at present it is not feasible to implement fully optical adaptive signal processors but that in time it might be so. ‘Not yet’ is our surmise. A brief literature survey and description of existing prototype optoelectronic adaptive systems is also provided.
Model reference adaptive control for the azimuth‐pointing system of a balloon‐borne stabilized platform
Authors: Chingcuanco Alfredo O. , Lubin Philip M. , Meinhold Peter R. , Tomizuka Masayoshi 
Published: July 2007

AbstractA balloon‐born stabilized platform has been developed for the remotely operated altitude‐azimuth pointing of a millimetre wave telescope system. This paper presents a development and implementation of model reference adaptive control (MRAC) for the azimuth‐pointing system of the stabilized platform. The primary goal of the controller is to achieve pointing RMS better than 0.1°. Simulation results indicate that MRAC can achieve pointing RMS better than 0.01°. Ground test results show pointing RMS better than 0.03°. Data from the first flight at the National Scientific Balloon Facility (NSBF), Palestine, TX show pointing RMS better than 0.02°.
Stable adaptive control system subject to bounded external disturbances
Authors: Cheng Shao 
Published: July 2007

AbstractBy means of minimizing a quadratic cost function and employing a modified least squares estimator with a dead zone, a new self‐tuning controller is derived. Under simple assumptions the stability of the resulting closed‐loop adaptive control system is ensured in the presence of bounded external disturbances even for non‐minimum phase systems. The analysis performed also gives the upper bounds of tracking errors and parameter estimates. For the disturbance‐free case a modified version of the basic algorithm ensures asymptotic stability, i.e. the output error converges to zero, without any additional assumptions. Simulation results demonstrate the effectiveness of the new controller.