Miracle-dz/UniFAR-FTUs huggingface dataset:
Asymptotic expansions to improve large sample confidence intervals for system reliability

SUMMARY Asymptotic expansions are used to provide first- and second-order adjustments to large sample approximations for system reliability confidence intervals obtained from component test data. The effectiveness of the adjustments for sample sizes of practical interest is demonstrated by numerical comparisons with results obtained using exact methods and also by a Monte Carlo study for systems with known reliabilities. Some key word8: Asymptotic expansion; Confidence limit; Cumulant; Nuisance parameter; System reliability function. An important problem in reliability is the construction of confidence intervals for system reliability from component test data. The testing of completed systems such as missiles or communications satellites can be very expensive whereas component test data are usually available prior to system assembly. In this context component reliabilities are nuisance parameters and one consequence is that severe computational difficulties arise when confidence intervals are constructed using exact procedures. An account of these difficulties and a review of some approximate methods are given by Mann, Schafer & Singpurwalla (1974, Chapter 10). For systems in general the large sample theory of maximum likelihood or of likelihood ratio can be used. Comparisons have shown that the likelihood ratio approach is superior to maximum likelihood but it is difficult computationally and neither method is satisfactory for sample sizes of practical interest. For binomial test data and a general system reliability function we give first-order adjusted asymptotic expansions which yield much improved confidence intervals. When test data consist of times to failure the numbers of failures are usually small compared to the sample sizes used for binomial testing and two adjustments are required to give effective improvements. An important case is a series system with exponentially distributed component lifetimes. Here the Lehmann-Scheff6 theory can be applied to give optimum, i.e. uniformly most accurate unbiased, confidence limits (Lentner & Buehler, 1963). The asymptotic expansion which is given explicitly for this case provides good approximations, especially when exact computation becomes difficult. The availability of separate estimates for the individual parameters makes a general discussion feasible. The method used to derive the expansions is a multiparameter extension of a single parameter approach given by Winterbottom (1979). They admit mixed tests on components where, say, for some component types the test data is binomial and for the remaining types exponential failure times are observed. A minimum of one failure is required for both kinds of test data.
Dynamics of Articulated Structures. Part I. Theory

ABSTRACT A finite element based method is developed for geometrically nonlinear dynamic analysis of spatial articulated structures; i.e., structures in which kinematic connections permit large relative displacement between components that undergo small elastic deformation. Vibration and static correction modes are used to account for linear elastic deformation of components. Kinematic constraints between components are used to define boundary conditions for vibration analysis and loads for static correction mode analysis. Constraint equations between flexible bodies are derived in a systematic way and a Lagrange multiplier formulation is used to generate the coupled large displacement-small deformation equations of motion. A lumped mass finite element structural analysis formulation is used to generate deformation modes. An intermediate-processor is used to calculate time-independent terms in the equations of motion and to generate input data for a large-scale dynamic analysis code that includes coupled e.
Three-dimensional vascular reconstruction from projections: a theoretical review

The three-dimensional reconstruction of vascular networks from X-ray projection images is reviewed in analogy to general three-dimensional computed tomography. Intrinsic vascular bed properties (connectivity, density (spareness), lumen dimensions, radio-opaque contrast uniformity, etc.) suggest a general data representation, provide a basis for the algorithmic nature of reconstruction, and can be used to predict tradeoffs between reconstruction accuracy, number of views, and view orientation. <<ETX>>
FORCED THREE-DIMENSIONAL HOMOGENEOUS TURBULENCE WITH HYPERVISCOSITY

High-resolution numerical simulations (up to 2563 modes) are performed for the Navier-Stokes equations with hyperviscosity (−1)h+1 Δh (h = 8). With random white-in-time forcing, the inertial-range energy spectrum has the scaling law 1/kα with α ≈ 1.85 ± 0.05 at small wave numbers k with a flatter region near the ultraviolet cut-off. The transitional region is characterized by a sharp change of the energy transfer mechanism. Spectra of fluctuations of higher-order correlation functions are measured. At inertial-range scales the system seems insensitive to the power h of the hyperviscosity.
Perceptual evidence for allophonic variation of the palatal fricative /ç/ in spontaneous Berlin German.

Auer (2004) postulates that the multi‐ethnolect Kiezdeutsch (Berlin, Germany) differentiates three realizations of /ɪc/: [ɪc]; [ɪ∫]; [ɪφ]. Acoustic analyzes of 1192 tokens of /c/ from the ZAS‐spontaneous speech database (collected from nine adolescent speakers of the Kiezdeutsch multi‐ethnolect as spoken in Berlin) showed no reliable differences in kurtosis, skewness, cog, or peak between items impressionistically categorized into these three groups. Further, in the spontaneous speech of middle‐aged monolingual speakers of the local Berlin dialect [∫] variants of /c/ were also detected, although here this alternation is not attested. The hypotheses are (1) that Berlin‐German also has [∫] as an allophonic variant of /c/ and (2) that Kiezdeutsch has a 3‐way‐split of this category. To evaluate the perceptual validity of these assumptions, tests are being conducted asking native Berliners to rate the category membership of excised variant realizations of /c/ and /∫/ from the Kiezdeutsch‐ and Berlin‐database o.
SUBBAND EMISSIONS OF INGAN MULTI-QUANTUM-WELL LASER DIODES UNDER ROOM-TEMPERATURE CONTINUOUS WAVE OPERATION

The emission spectra of InGaN multi-quantum-well (MQW) laser diodes (LDs) under continuous-wave (CW) operation at room temperature (RT) showed periodic subband emissions with an energy separation of 2 meV. The peak wavelength of the laser emission was measured as a function of the operating current. The peak wavelength showed mode hopping toward higher energy with increasing operating current. Each single-mode laser emission was located at a peak of each periodic subband emission. These periodic subband emissions probably result from the transitions between the subband energy levels of the InGaN quantum dots formed from In-rich regions in the InGaN well layers. High-power InGaN MQW LDs with an output power of 40 mW were performed under RT CW operation.
Integer sequences having prescribed quadratic character

For the odd primes p, = 3, p2 = 5, ■ • -, we determine integer sequences Np such that the Legendre symbol (N/p,) = +1 for all pi S P for a prescribed array of signs ± 1; (i.e., for a prescribed quadratic character). We examine six quadratic characters having special interest and applications. We present tables of these Np and examine some applications, particularly to questions concerning extreme values for the smallest primitive root (of a prime N), the class number of the quadratic field R(J — N), the real Dirichlet L functions, and quadratic character sums.
Cooperative transition of electronic states of antisite As defects in Be-doped low-temperature-grown GaAs layers

Magnetic properties resulting from localized spins associated with antisite arsenic ions AsGa+ in Be-doped low-temperature-grown GaAs (LT-GaAs) layers were studied by measuring the magnetization of lift-off samples. With fast cooling, the magnetization of samples at 1.8 K becomes significantly lower than that expected from Curie-type paramagnetism in the range of the applied field to 7 T, and a transition from low magnetization to the magnetization of paramagnetism occurs upon the heating of samples to 4.5 K. With slow cooling, on the other hand, samples have a paramagnetic temperature dependence throughout the measurement-temperature range. The magnetization was found to decrease monotonically when a sample was kept at a fixed low temperature. These observations are explained by the cooperative transition of electron states of AsGa defects, which is closely related to the normal-metastable state transition of EL2 defects in semi-insulating GaAs. The results of the magnetization measurements in the presen.
A Census of Planar Maps

In the series of "Census" papers, of which this is the fourth, we attempt to lay the groundwork of an enumerative theory of planar maps (12, 13, 14). The maps concerned are rooted in the sense that some edge is fixed as the root, and a positive sense of description and right and left sides are specified for it. This device simplifies the theory by ruling out the possibility of a map being symmetrical.
A comparison of finite-difference and spectral-element methods for elastic wave propagation in media with a fluid-solid interface

The numerical simulation of wave propagation in media with solid and fluid layers is essential for marine seismic exploration data analysis. The numerical methods for wave propagation that are applicable to this physical settings can be broadly classified as partitioned or monolithic: The partitioned methods use separate simulations in the fluid and solid regions and explicitly satisfy the interface conditions, whereas the monolithic methods use the same method in all the domain without any special treatment of the fluid-solid interface. Despite the accuracy of the partitioned methods, the monolithic methods are more common in practice because of their convenience. In this paper, we analyse the accuracy of several monolithic methods for wave propagation in the presence of a fluid-solid interface. The analysis is based on grid-dispersion criteria and numerical examples. The methods studied here include: the classical finite-difference method (FDM) based on the second-order displacement formulation of the elastic wave equation (DFDM), the staggered-grid finite difference method (SGFDM), the velocity-stress FDM with a standard grid (VSFDM) and the spectral-element method (SEM). We observe that among these, DFDM and the first-order SEM have a large amount of grid dispersion in the fluid region which renders them impractical for this application. On the other hand, SGFDM, VSFDM and SEM of order greater or equal to 2 yield accurate results for the body waves in the fluid and solid regions if a sufficient number of nodes per wavelength is used. All of the considered methods yield limited accuracy for the surface waves because the proper boundary conditions are not incorporated into the numerical scheme. Overall, we demonstrate both by analytic treatment and numerical experiments, that a first-order velocity-stress formulation can, in general, be used in dealing with fluid-solid interfaces without using staggered grids necessarily.
Delay-dependent decentralised H α filtering for fuzzy interconnected systems with time-varying delay based on Takagi¿Sugeno fuzzy model

This study focuses on the problem of delay-dependent H ∞ filter design for non-linear interconnected systems with time-varying delays via Takagi–Sugeno fuzzy models. Based on the delay-dependent fuzzy Lyapunov–Krasovskii functional and the fuzzy-free weighting matrix technique, the delay-dependent stability and a prescribed H ∞ performance index are guaranteed for the overall filtering-error system. In addition, a sufficient condition for the existence of such a filter is established by using linear matrix inequalities that are numerically feasible. Finally, two examples are given to demonstrate the effectiveness and advantage of the proposed approach.
Vector optimization with cone semilocally preinvex functions

In this paper we introduce cone semilocally preinvex, cone semilocally quasi preinvex and cone semilocally pseudo preinvex functions and study their properties. These functions are further used to establish necessary and sufficient optimality conditions for a vector minimization problem over cones. A Mond-Weir type dual is formulated for the vector optimization problem and various duality theorems are proved.
Modal Propagation of High Frequency Electromagnetic Waves in Straight and Curved Tunnels Within the Earth

Modal propagation in tunnels within the earth environment is considered for the case of rectangular and circular shaped tunnels excited by high frequency electromagnetic fields. It is shown that when the applied frequency is sufficiently high, simple forms of the modal fields exist for tunnels with rectangular cross section. The dominant modes in a circular tunnel are hybrid balanced modes in the high frequency limit. Closed form expressions for the modal attenuation rates of the dominant modes in rectangular and circular tunnels are derived and assessed against numerical solutions of the modal equations based on constant surface impedance wall assumption. The case of a curved rectangular tunnel is studied using the Airy function representation of the modal fields. Modal propagation constants in curved tunnels for different polarizations are obtained and it is shown that the tunnel curvature can drastically increase the modal attenuation. Numerical results show that the modes having perpendicular electric field to the curved walls suffer higher attenuation than those modes with the electric field parallel to the curved walls.
Partial Lyapunov Strictification: Smooth Angular Velocity Observers for Attitude Tracking Control

A smooth angular velocity observer is proposed for the attitude tracking control of a rigid body in the absence of angular velocity measurements. The observer design ensures asymptotic convergence of angular velocity state estimation errors irrespective of the control torque or the initial attitude state of the spacecraft. Unlike existing rate observer formulations that attain estimation error convergence by imposing certain switching conditions or hybrid logic, the proposed observer has a smooth structure that ensures C∞ continuity of all estimated states. Furthermore, the combined implementation of the proposed observer with a proportional-derivative type of attitude control law leads to an important “separation property. ” In particular, an independently designed proportional-derivative control law driven by angular velocity estimates generated from the smooth observer results in (almost) global asymptotic stability of the overall closed-loop tracking error dynamics. The main feature of this key technic.
Remotely Sensed Measurements of Stratocumulus Properties during FIRE Using the C130 Aircraft Multi-channel Radiometer

Abstract This paper gives a description of a narrow-hand near-infrared radiometer that was operated during the marine stratocumulus intensive field observation program of FIRE in 1987 from the United Kingdom Meteorological Office C130 aircraft. All data with small solar zenith angles and continuous stratocumulus sheets have been analysed. A method to determine cloud optical depth and effective radius of the drop size distribution is presented from both reflectance and transmittance data. The data demonstrate that different cloud droplet sizes were successfully distinguished and realistic optical depths were obtained. Absolute comparison with in situ droplet effective radii measurements showed an inconsistency, remotely retrieved values being up to 50% larger than the in situ values.
Dynamic Stall Modeling for the Conditions of Vertical Axis Wind Turbines

Unsteady aerodynamics imposes additional demands on the modeling of vertical axis wind turbines. Large variations in the angles of attack of the blades cause force oscillations, which can lead to the fatigue-associated problems. Therefore, an accurate estimation of the dynamic loads is essential for the vertical axis wind turbines design. Dynamic stall modeling is in focus because it represents complex phenomena associated with the unsteady flow conditions. The purpose of the study is to find a suitable dynamic stall model for the vertical axis wind turbine conditions. Three versions of the Leishman–Beddoes model are explicitly presented. Additional modifications are implemented for the model to work when the angles of attack change sign and have high amplitudes. All the model parameters are presented. The model is assessed against measured data. The conditions for the simulation tests are close to the vertical axis wind turbine operational conditions. A version of the model, originally designed for low M.
Effect of Pivot Point on Aerodynamic Force and Vortical Structure of Pitching Flat Plate Wings

This paper reports aerodynamic forces and 2D PIV velocity measurements on a rectangular wing with an effective aspect ratio 4 during a pitch ramp-hold wing motion at reduced frequencies from 0.022 to 0.39. The parameter space in terms of the Stokes number and the Reynolds number is used to correlate pitch rate and free stream velocity effects. The maximum angle of attack is 45 degrees and pivot locations, such as leading edge pivot, midchord pivot, and trailing edge pivot, are considered. The evolution of aerodynamic forces as functions of convective time, pitching time, and angle of attack are discussed. Noncirculatory effects are observed for reduced frequency higher than 0.13. For leading edge pivot axis non-circulatory effects produce a positive force spike at the start of rotation and a negative spike at the end of rotation. The opposite is found for trailing edge pivot. For midchord pivot the non-circulatory force spikes are not present. Rotation rate effects are observed during the constant rate part of the motion for reduced frequency higher than 0.065. For leading edge pivot axis non-circulatory effects and rotation rate effects combine to produce very large lift and drag coefficients. Incipient vortex shedding is observed at high reduced frequency during the hold phase for convective times in the range 4-20. For reduced frequency lower than 0.022 the flow is quasi steady and lifting line theory provides good estimates of lift for angle of attack below the steady stall angle. Although significant leading edge suction was measured at the final steady state condition, projection of the normal force in the drag direction is the main contribution to the drag. PIV measurements show the flow topology for different pivot axes. For leading edge pivot axis a starting vortex is formed at the trailing edge which promotes development of the LEV and enhances aerodynamic forces. For mid-chord pivot axis starting vortices are formed at the leading and trailing edges. For trailing edge pivot axis the starting vortex is formed at the leading edge only. Formation of a starting vortex at the leading edge delays development of the LEV and inhibits aerodynamic force generation.
Recursive functions and intuitionistic number theory

The purpose of this paper is to examine, for propositions of elementary number theory, the relation between an intuitionistic truth definition and the provability of formulas which represent these propositions in formal systems of intuitionistic logic. The intuitionistic truth definition is that of Kleene(1). He has arithmetized this truth notion in the definition of a syntactical predicate "the natural number a realizes the number-theoretic formula A" [15, §5]. A familiarity wi', a this definition as well as other portions of Kleene's paper will be presupposed for the following. The present results relate the constructibility demands of the intuitionists as embodied in a formal system of number theory by Heyting to Church's thesis identifying constructible and general recursive functions [8; 9; 3]. In Part I, it is shown that certain systems of intuitionistic number theory satisfy the definition for realizability. We demonstrate that any formula deductible from a realizable formula in one of these formal systems is realizable. This result enables us, by the reasoning of Kleene [15, §10 ], to show that certain classically true formulas are not provable in intuitionistic number theory. Likewise, it affords a demonstration that certain classically true formulas of the predicate calculus are unprovable in the intuitionistic predicate calculus. Then, following Kleene's notation [15, §§11-12], we demonstrate that the formulas AZ)®A and ®A3A are realizable. This result concerns an interpretative consistency proof for a system of intuitionistic number theory which is an extension of the usual formalization [15, §13]. Parts II and III take up the problem of formalizing a portion of the theory of recursive functions and predicates in intuitionistic number theories. Part II is concerned principally with the formalization of material which is familiar on the intuitive plane and much of which has already been formalized in the framework of a classical logic. We utilize the work of Hubert and Bernays [10, vol. l] and Gödel [ó] to avoid additional laborious detail. Part III introduces formulas Kk(e, ai, • • • , ak, b) representing primitive recursive predicates having properties similar to Kleene's predicates Tk(e, ax, • • • , ak, b) [13, §§4, 7], but defined in a way which facilitates formalization of the theory of general and partial recursive functions and predicates. These formulas en-
A New Feigenbaum-Like Chaotic 3D System

Based on Sprott N system, a new three-dimensional autonomous system is reported. It is demonstrated to be chaotic in the sense of having positive largest Lyapunov exponent and fractional dimension. To further understand the complex dynamics of the system, some basic properties such as Lyapunov exponents, bifurcation diagram, Poincare mapping, and period-doubling route to chaos are analyzed with careful numerical simulations. The obtained results also show that the period-doubling sequence of bifurcations leads to a Feigenbaum-like strange attractor.
Acoustic analysis of the English pronunciation of Japanese high school teachers and university students.

As Japan attempts to meet the demands of the Ministry of Education by introducing English‐as‐a‐foreign‐language (EFL) classes in all elementary schools, there has been a shortage of qualified native Japanese EFL teachers. The English communicative ability (and pronunciation, in particular) of Japanese EFL teachers varies across educational levels throughout Japan and even within individual prefectures. This study presents an acoustic analysis of 77 Fukushima Prefecture junior and senior high school Japanese EFL teachers’ read speech, comparing the two levels. It also presents an analysis of 133 Japanese university students’ read speech, recorded both before and after 14 weeks of weekly 90‐min explicit pronunciation instruction. The reading passage was the “Please call Stella” paragraph from the speech accent archive (http://accent.gmu.edu/). Detailed analyses of vowel formants, voice onset time, fricative spectral peaks, and intonation were carried out using PRAAT and will be presented. The data have impl.