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In this study, a hypoplastic model is developed to describe the mechanical behaviors of cemented sand under both monotonic and cyclic loading conditions. A state variable is proposed to qualify the bonding strength, and it is incorporated into the model to reflect the influence of cementation on the strength, stiffness, and dilatancy of sand. To reflect the bonding degradation, this variable evolves during the shearing following a simple evolution rule and may vanish after large deformation. The critical void ratio and friction angle are related to the initial cemented content to consider the variation of the critical state induced by the cementation. The model is subsequently extended to account for cyclic loading by incorporating the intergranular strain, fabric change effect, and semifluidized state. The capability of the model is demonstrated by simulating the behavior of cemented sand under both monotonic and cyclic loading conditions. [ABSTRACT FROM AUTHOR]

This study presents a novel formulation for incorporating anisotropy into the generalized plasticity constitutive model. Generalized plasticity is a hierarchical framework allowing for extensibility, in order to encompass new phenomena and improve its predictive capabilities. Anisotropy formulation is based experimentally on the phase transformation state and considers explicitly the direction of the maximum principal stress and the magnitude of the intermediate principal stress, through an anisotropy state variable that contributes to the state parameter. Additionally, the model incorporates the fabric using an evolving fabric variable that reflects initial fabric due to sample preparation method for granular soils. The formulation is simple and introduces three constitutive parameters, allowing for straightforward implementation into the constitutive model and direct application in finite element analysis. The model is validated with undrained triaxial tests conducted on Toyoura sand, covering a wide range of initial conditions with a unique set of constitutive parameters, and yielding overall satisfactory results despite some limitations. [ABSTRACT FROM AUTHOR]

The analysis of real-world data in classical statistics is commenced by deriving a density function which requires a lengthy function selection and parameter estimation process. The process is supported by difficult integration to obtain the cumulative frequency function. In view of the difficulties in the existing methods, a super function called the Persian Probability Curve is proposed in this paper. This function is based on logical reasoning and mathematical concepts to overcome the shortcomings of the classical method. It is shown that the Persian probability is equivalent to that of the Burr in the governing differential equation. The validity of the work has been verified by comparing the obtained results with those of others. [ABSTRACT FROM AUTHOR]

To improve the optimization accuracy and efficiency, state variable and optimization potential-based multi-objective optimization (MOP) method is introduced. State variable records whether the simulation failed, which caused by ill geometry and mismatched predetermined boundary condition, and is consequently incorporated into objective function through weighted average method to improve the accuracy of surrogate model and optimization. Optimization potential, which represents the difference between present performance and ideal optimal objective, can be used to direct MOP and avoids the manual selection of weight vectors. Four optimization cases, including traditional weighted optimization, state variable based optimization, optimization potential based optimization, and the optimization combined presented two methods, are applied to optimize a typical compressor blade airfoil and demonstrate the proposed optimization method. Results show that the combination of these two methods produces the best optimization result. In which the state variable method generates most of improvement in optimal performance and the optimization potential method notably improves optimal performance under large incidences. The introduction of state variable excludes the invalid objective values at one sample point rather than directly removing or keeping, so that the accuracy of surrogate model is significantly improved and obtains better optimal results. The distribution of optimization potential among each incidence is similar to that of weight vector. Using its summation to construct objective function can be deemed as automatically assigning a preferable weight vector and the optimal result consequently presents slight preferable performance. [ABSTRACT FROM AUTHOR]

The performance of Kalman filters designed for nonlinear systems often degrades with the increase of nonlinear degree. In order to make up for the shortcomings of extended Kalman filter and unscented Kalman filter in the online process, this study proposes an extended dimension Kalman filter method based on hidden variable for a class of strongly nonlinear systems composed of the accumulation of linear and non-linear terms. In this method, the nonlinear term is defined as the hidden variable of the original system, and the linear dynamic correlation model about the hidden variable is established. The hidden variable is extended to the original state variable of the system, so as to establish the linear system model based on the original variable and hidden variable. Finally, the high-order extended dimension Kalman filter of this kind of system is designed. Through MATLAB simulation, the effectiveness and accuracy of the performance of the designed filter are verified. [ABSTRACT FROM AUTHOR]

The classical methods for stability analysis of structures contain some levels of epistemic uncertainty. This paper presents an alternative method for the analysis of system stability phenomena. The analysis is conducted by using a new method which is called the change of state philosophy. The phenomenon is considered as the change in the state of the system in this method. The basic principle in the formulation is the use of an equation in which the product of the key parameter of the system and its inverse is set equal to 1. Logical reasoning and mathematics principles are used to explicitly derive the basic theory. The results are presented as the Persian curve which is a super function of the state functions. The accuracy of the proposed method has been verified by using several examples related to the ultimate strength analysis of structural systems. The state functions are defined as explicit functions of the state variable. The state variable is an identification parameter of the system. [ABSTRACT FROM AUTHOR]

The paper analyses the state of applied optimal control theory in automated control synthesis problems and the issues of its practical implementation. The cases of nonlinear and linear plants in a closed and open loop are considered. There are several problems that manifest themselves in the implementation of theoretical solutions or in computer modeling. Such problems include: the choice of the control prediction horizon, the appearance of a static control error, ensuring an adequate stability margin, determining the set values of state variables, and choosing a multidimensional insensitivity zone of the state controller. For each of the problems raised, ways to resolve them are proposed. [ABSTRACT FROM AUTHOR]

An intrinsic definition of state is given for systems described by higher-order linear differential equations with time-varying coefficients. Based on this definition we characterize a polynomial differential operator that, acting on a system trajectory, defines a corresponding state trajectory, and we illustrate a procedure to compute a state variable from the differential equations. We prove that there exist representations of first order in such state variable and zeroth order in the input and output variables. We also consider linear, time-varying dissipative systems, and we give several characterizations of the property of cyclo-losslessness. We prove that for dissipative systems the storage function is a quadratic function of the state. [ABSTRACT FROM AUTHOR]

A metric structure is imposed on state space such that solutions to 1st order state variable model of a linear system are geodesics subject to restrictions on the system and input matrices. For linear time invariant systems, a 2nd order state variable model of an extended system to a given 1st order model is derived. The metric is tailored to systems under consideration. [ABSTRACT FROM AUTHOR]

In this study, the authors derive a new type of maximum principle for both stochastic evolution and parabolic type stochastic partial differential systems. The systems only require the Hamiltonian functional to be concave in the state variable rather than in both state and control variables. They also show a connection between these two types of systems. Finally, examples are given to illustrate the authors' theoretical results. [ABSTRACT FROM AUTHOR]

A recursive rejection filter (REF) oriented to the radar signal extraction from the moving targets on a background of passive interference in the form of undesired re ections from fixed or slowly moving objects (so-called clutter) is the object under investigation. By means of the state variable method, which gives the adequate filter description in the time domain, the REF structure in the transient mode is synthesized, which is improved with the aim of transient acceleration with the clutter edge arriving. The REF structure's improvement in the transient mode is achieved by its reconfiguration, which is made by REF output and feedback switching. The steady-state values of decorrelated rejection residues from the nonrecursive REF part are passed to the REF output and to feedback circuits, which practically eliminates a "ring" in the feedback circuits, which is caused by the mean value and uctuations of the clutter samples, and significantly accelerates the transient at the REF output. The structure diagram of the reconfigurable RF in the transient mode by means of recursive couplings switching is offered. A solution of transient acceleration problems for recursive REFs allows substantive utilization of required characteristics of REFs and their exible control. A comparative analysis of clutter REF rejection effectiveness of fixed and reconfigurable structures is performed in the transient mode. It is shown that REF structure reconfiguration by means of recursive coupling switching essentially reduces the transient duration in the filter and increases the clutter rejection effectiveness in the transient operation mode. [ABSTRACT FROM AUTHOR]

A viscosity model for suspensions of rigid particles with predictive capability over a wide range of particle volume fraction and shear conditions is of interest to quantify the transport of suspensions in fluid flow models. We study the shear viscosity of suspensions and focus on the effect of particle aspect ratio and shear conditions on the rheological behavior of suspensions of rigid bi-axially symmetric ellipsoids (spheroids). We propose a framework that forms the basis to microscopically parameterize the evolution of the suspension microstructures and its effect on the shear viscosity of suspensions. We find that two state variables, the intrinsic viscosity in concentrated limit and the self-crowding factor, control the state of dispersion of the suspension. A combination of these two variables is shown to be invariant with the imposed shear stress (or shear rate) and depends only on the particle aspect ratio. This self-similar behavior, tested against available experimental and numerical data, allows us to derive a predictive model for the relative viscosity of concentrated suspensions of spheroids subjected to low (near zero) strain rates. At higher imposed strain rates, one needs to constrain one of the state variables independently to constrain the state of dispersion of the suspension and its shear dynamic viscosity. Alternatively, the obtained self-similar behavior provides the means to estimate the state variables from the viscosity measurements made in the laboratory, and to relate them to microstructure rearrangements and evolution occurring during deformation. [ABSTRACT FROM AUTHOR]

One important challenge in controller design for Doubly-Fed Induction Generator (DFIG) or dynamic analysis of networks with DFIGs, is its nonlinearity besides invisibility of some important state variables. In this paper, a state estimation algorithm based on Extended Kalman Filter (EKF) is proposed for grid connected DFIG. A complete 15th order nonlinear model of DFIG equipped with a nonlinear controller is utilized, and all state equations are derived in appropriate form to be used for EKF. The results of the proposed state estimation algorithm can be used for modeling and analysis of any disturbance such as wind speed variations or faults occurrence in the network. To obtain electrical measures required for state estimation, a Phasor Measurement Unit (PMU) is utilized and all measurement and process noise are modeled. Accuracy of the proposed algorithm is evaluated by five different case studies covering the effect of initial guess for state variables, the effect of process and measurement noises, variation in wind speed and occurrence of a solid short circuit close to the DFIG. The simulation results demonstrate robustness and accuracy of the proposed algorithm in estimating dynamic state variables. [ABSTRACT FROM AUTHOR]

The shape control of probability density function (PDF) is an important subject in stochastic systems. The PDF-shaping control study has ranged from linear systems to non-linear systems. In this paper we present a PDF-shaping control technique which is useful for a class of non-linear stochastic systems. Controlling the PDF shape requires designing a controller to make the state PDF follow the goal PDF; it is actually to determine the gains of the controller. As we know, the stationary PDF of the state variable is equivalent to the solution of the Fokker–Planck–Kolmogorov (FPK) equation arising from the stochastic system driven with Gaussian white noise. After designing the controller, we derive the solution with some parameters to the corresponding FPK equation, and then solve out the parameters in the solution by the linear-least-squares method, therefore obtaining the gains of the controller. Finally, simulation experiments have been carried out to verify the effectiveness of the approach. [ABSTRACT FROM PUBLISHER]

The problem of robust stochastic stability and delayed‐state‐feedback stabilisation of uncertain Markovian jump linear systems with random Markov delays is investigated. Based on the Lyapunov stability theory and robust analysis techniques, some robust stochastic stability criteria are derived in terms of linear matrix inequalities. Robust delayed‐state‐feedback controllers that stochastically stabilise the uncertain Markovian jump linear systems is also proposed. The state variable on the controller is assumed to be dependent on the Markov delay that has uncertain transition probabilities. Finally, numerical examples are provided to illustrate the feasibility and effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

The control and stabilization of resonant converters are essential problems in power electronics. The conventional controller design and stability analysis for these converters are based on the linearized averaged model. Nevertheless, the state variables in resonant converters have large ac variations and the validity of the linearized average model is violated. Hence, using large signal and nonaveraged models are necessary for controller design and stability analysis. In this paper, a new hybrid controller is presented that is applicable to dc-dc series resonant converters and use neither averaging nor small signal approximation. The dc-dc resonant converters are inherently switched affine systems with constrained switching law. The proposed controller is based on the switched behavior of the converter and the concept of piecewise affine methodology. Moreover, it has switched inner and proportional-integral (PI) outer control loops and does not require a modulator. The large signal and closed loop stability analysis of the resonant converters is presented by a theorem. The minimum phase attribute of the control system is investigated by zero dynamic stability analysis. The proposed controller has less complexity in comparison to other suggested controllers and can be implemented using simple analog circuits. The simulation and experimental results show the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This paper evaluates the potential of spaceborne bistatic interferometric synthetic aperture radar images for the monitoring of biophysical variables in wetlands, with a special interest on paddy rice. The assessment is made during the rice cultivation period, from transplanting to harvesting time (May to October) for fields around Gala lake (Turkey), one of the largest and most productive paddy rice planting area in the country. Detailed ground truth measurements describing biophysical parameters are collected in a dedicated campaign. A stack of 16 dual-pol TanDEM-X images is used for the generation of 32 digital elevation models (DEMs) over the studied area. The quality of the data allows the use of the interferometric phase as a state variable capable to estimate crop heights for almost all the growing stages. The early vegetative rice stage, which is characterized by flooded fields, cannot be represented by the interferometric phase due to a low signal-to-noise ratio but can be easily detected by amplitude and interferometric coherence thresholding. A study on the impact of the polarization in the signal backscatter is also performed. An analysis of the differences between HH and VV DEMs shows the varying signal penetration for the two polarizations at different growing stages. The validation with reference data demonstrates the capability to establish a direct relationship between interferometric phase and rice growth. The very high coherence of TanDEM-X data yields elevation estimates with root-mean-square error in a decimetric level, supporting temporal change analysis on a field-by-field basis. [ABSTRACT FROM PUBLISHER]

This study proposes an adaptive approximation‐based control approach for non‐linear pure‐feedback systems in the presence of full state constraints. Completely non‐affine non‐linear functions are considered and assumed to be unknown. The dynamic surface design based on integral barrier Lyapunov functionals is provided to achieve both the desired tracking performance and the constraints satisfaction, in consideration of the full‐state‐constrained non‐affine non‐linearities. In this design procedure, simple sufficient conditions for choosing control gains, which can be checked off‐line, are established to guarantee the feasibility of the controller. The function approximation technique is employed to estimate unknown non‐linearities induced from the controller design procedure where the adaptive laws using the projection operator are designed to ensure the boundedness of the function approximators in the feasibility conditions. It is shown that all the signals in the closed‐loop system are uniformly ultimately bounded and the tracking error converges to an adjustable neighbourhood of the origin while all state variables always remain in the constrained state space. [ABSTRACT FROM AUTHOR]

This paper examines the impact of health expenditures on agricultural labour productivity in order to inform the necessary policy decisions about targeting scarce public resources towards their most effective uses. We link health sector expenditures in rural Tanzania to health outcomes and agricultural labour productivity using data from the 2008 Household Budget Survey (10,975 households) and the 2007/08 Agricultural Census (52,594 households) across 113 districts in Tanzania. The results indicate that the marginal productivity of labour as well as land and fertilisers respond significantly to health expenditures. However, the magnitude of the response varies across types of disease, categories of expenditures and agricultural inputs. These findings suggest both the need and scope for targeting public expenditures in the health sector to achieve better agricultural growth outcomes. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the existence of an optimal solution of a functional restricted to non-linear partial differential equations, which ruled the dynamics of viscous and incompressible stratified fluids in R 3 . Additionally, we use the first derivative of the considered functional to establish the necessary condition of the optimality for the optimal solution. [ABSTRACT FROM AUTHOR]

Abstract: This paper derives two canonical state space forms (i.e., the observer canonical form and the observability canonical form) from multiple-input multiple-output systems described by difference equations. The state space model is expressed by the first-order difference equation and is equivalent to the input–output representation. More specifically, by setting the different state variables, the difference equations or the input–output representations can be transformed into two observable canonical forms and the canonical state space model can be also transformed into the difference equations. Finally, two examples are given. [Copyright &y& Elsevier]

Abstract: Earthquakes can be considered to be a result of tribological instability in the system of faults of the Earth''s crust. Similar instabilities can be reproduced and studied in detail in laboratory-scale experiments. In this work, the earthquake model under study is a tribosystem with pronounced stick–slip behavior. Measurement of the motion of the system with a resolution of 8nm shows that slow creep is actually observed throughout the stick stage and it accelerates as the instability point is approached. This motion is regular enough to serve as a basis for the prediction of the onset of instability. It is shown that the motion of a solid, both at the stage of slow creep and at that of fast slip is well described by Dieterich''s friction law, which takes the dependence of friction on sliding velocity and internal state variable into account, if we supplement it with the contribution of local contact compliance. In the immediate vicinity of the instability point, a universal behavior is observed, making highly accurate prediction of the onset of unstable slip from creep observations possible. We show that observation of the creep preceding a tribological instability makes both short term and long term predictions of the time until instable sliding in laboratory models possible. The problems of extending this approach to real distributed systems are discussed. [Copyright &y& Elsevier]

Understanding the fundamental issues related with the effect of shear velocity on frictional characteristics at the interface of rock surfaces is an important issue. In this paper, strain-rate dependence on friction is investigated in relation to sliding behaviour under normal load. The phenomenon of stick-slip of granite and shaly sandstone with a tribometer at constant rate of strain under normal loads was observed. Friction at the interface of the rock samples was developed by increasing shear strain at a constant rate by applying constant velocity using the tribometer. For shaly sandstone, state parameters ( a and b) played a major role in determining the friction values and roughness of the contact surfaces as well. Higher values of b for shaly sandstone may be attributed to the fact that its surface had a greater number of pronounced asperities. Rubbing between the surfaces does not mean that surface becomes smoother. This is because of variation of friction between surfaces. [ABSTRACT FROM AUTHOR]

Abstract: In this Note, a thermodynamic description is proposed to include the gradient of the temperature in the set of state variables. It is based upon an original expression of the entropy and of the internal energy taking account of the presence of the temperature gradient by Legendre transform with respect to the variable . The proposed description can be justified in a homogenization process. In particular, the associated heat equation is derived and discussed in comparison with the existing results of the literature. It is shown that this equation removes the paradox of instantaneous propagation. [ABSTRACT FROM AUTHOR]

The modular construction of many plants and animals defies conventional approaches to the study of life histories and population dynamics. An important complication of modular construction is that individuals can rapidly decrease in size when some modules are removed or die or when an individual fragments. Most attempts to describe life histories and population dynamics of modular organisms classify individuals according to their size. This approach relies on the fundamental assumption that fragmentation and module loss have no consequences for an individual apart from a simple decrease in size. Here we experimentally test this assumption. Using a modular marine invertebrate, the encrusting bryozoan Warersipora subtorquara, as a model species, we manipulated colony size and then assessed performance against three potential explanatory models based on size, age, and damage. In a second experiment we disrupted the internal modular demography of colonies to determine whether the performance of a fragment is influenced by the type of modules that remain. Finally, we investigated how constraints on growth in modular organisms uniquely influence growth after module loss. We found that single-state variables such as size or age do not describe performance in our species. Internal constraints substantially reduce growth after a decrease in size, and the age of modules that remain determines the timing of reproductive onset and fecundity. A knowledge of the size history of individuals, including any decreases in size, is necessary to accurately describe life histories and population dynamics in this modular organism. Our results have major consequences for established methods for modeling the demography of modular organisms. [ABSTRACT FROM AUTHOR]

Void ratio has traditionally been used as a state variable for predicting the liquefaction behaviour of soils under the critical state soil mechanics framework. Recent publications show that void ratio may not be a good state variable for characterizing sand with fines. An alternative state variable referred to as the equivalent granular void ratio has been proposed to resolve this problem. To calculate this alternative state variable, a b parameter is needed. This b parameter represents the fraction of fines that actively participate in the force structure of the solid skeleton. However, predicting the value of b is problematic. Most, if not all, of the b values reported were determined by case-specific back-analysis, that is, the b value was selected so that a single correlation between equivalent granular void ratio and the measured steady state strength (or cyclic resistance) could be achieved. This paper examines the factors affecting the b value based on published work on binary packing. This leads to a simple semi-empirical equation for predicting the value of b based on fines size and fines content. Published data appear to be in support of the proposed equation. A series of experiments were conducted on a specially designed sand–fines type to provide additional validation of the proposed equation and to reinforce the use of equivalent granular void ratio in a more generalized context. [ABSTRACT FROM AUTHOR]

Void ratio has been used as a state variable for predicting the liquefaction behaviour of soils under the critical state, sometimes also referred to as the steady state, framework. Recent publications show that void ratio may not be a good parameter for characterising sand with fines because the steady state line (or curve) in the e-log(p') space moves downward with increase in fines content until it reaches a threshold value referred to as the threshold fines content (TFC). Recently, an alternative state variable, referred to as the equivalent granular void ratio, has been proposed to resolve this problem. To calculate this alternative state variable, an additional parameter 'b' is needed. This parameter 'b' represents the fraction of fines that actively participate in the force structure of the solid skeleton. However, predicting the 'b' value is problematic. This paper examines the factors affecting the 'b' value based on published work on binary packing. This leads to a simple semi-empirical equation for predicting the 'b' value based on fines size and fines content. The proposed equations were evaluated with published data sets. Then, the concept of an equivalent granular steady state line is proposed. This concept was used to predict the location of SSLs for sand with different fines content from either the SSL of clean sand or the SSL of sand with a given fines content. The predictions agree well with experimental results. [ABSTRACT FROM AUTHOR]

Abstract: This paper investigates, experimentally and numerically, the effect of various surface treatments on the thermo-mechanical response of aluminum cylindrical missiles during warm water quenching. The surface coating treatments include specialized solutions of aluminum oxide, aluminum silicate hydroxide, and phosphate wetting agents, among others. It is shown that these surface treatments can have a strong impact on the wettability of the aluminum surface, the promotion of nucleate boiling and the magnitude of the residual stresses in the metal after quench. Temperature histories recorded during quench allowed surface heat-transfer coefficients to be computed using an inverse heat-transfer code, and the thermal data was later used in a FE code to predict the mechanical deformation and the residual stress state after quench. Comparisons of experimental data with FE results are included for selected cases. [Copyright &y& Elsevier]

Abstract: Parameter identification of chaos system based on unknown parameter observer is discussed generally. Based on the work of Guan et al. [X.P. Guan, H.P. Peng, L.X. Li, et al., Acta Phys. Sinica 50 (2001) 26], the design of unknown parameter observer is improved. The application of the improved approach is extended greatly. The works in some literatures [X.P. Guan, H.P. Peng, L.X. Li, et al., Acta Phys. Sinica 50 (2001) 26; J.H. Lü, S.C. Zhang, Phys. Lett. A 286 (2001) 148; X.Q. Wu, J.A. Lu, Chaos Solitons Fractals 18 (2003) 721; J. Liu, S.H. Chen, J. Xie, Chaos Solitons Fractals 19 (2004) 533] are only the special cases of our Corollaries 1 and 2. Some observers for Lü system and a new chaos system are designed to test our improved method, and simulations results demonstrate the effectiveness and feasibility of the improved approach. [Copyright &y& Elsevier]

Abstract: We examined various spatiotemporal patterns evolving in deformed adhesives during peeling. The patterns are regarded as a spatiotemporal distribution of a tunnel structure formed by the deformed adhesive, and are classified into the following four types: (A) uniform pattern with tunnel structure, (B) uniform pattern without tunnel structure, (C) striped pattern alternating between A and B in time, and (D) spatiotemporal pattern made by the coexistence of two regions with and without the tunnel structure. We are able to reproduce these patterns and the mechanical and statistical behaviors by constructing a model with a state variable representing the stability of the tunnel structure. The essential factor of the pattern formation is the competition between a local asymmetric interaction and a global coupling of the state variables. [Copyright &y& Elsevier]

Abstract: In this Note, the generalized standard approach is proposed as a consistent gradient theory to include the gradients of the temperature and of the internal parameter in the set of state variables. This theory is derived from a global point of view, developing the basic ideas of continuum thermodynamics. It leads to the appropriate expressions of the entropy and of the internal energy in terms of the free energy in the case of temperature gradient. The local governing equations of the proposed thermodynamical approach are derived. The formalism of the dissipation potential can be applied in the same spirit as in the classical description from the dissipation analysis. To cite this article: Q.-S. Nguyen, S. Andrieux, C. R. Mecanique 333 (2005). [Copyright &y& Elsevier]

In this paper, the possibility of using the gradients of the temperature and of the internal parameters as additional state variables in Continuum Thermodynamics is considered. The expressions of the two principles are discussed and Clausius–Duhem inequality is derived under an appropriate statement of the internal entropy production. Several formulations are proposed and compared to existing results in the literature. To cite this article: P. Ireman, Q.S. Nguyen, C. R. Mecanique 332 (2004). [Copyright &y& Elsevier]

A novel approach to model the system test phase of the software life cycle is presented. This approach is based on concepts and techniques from control theory and is useful in computing the effort required to reduce the number of errors and the schedule slippage under a changing process environment. Results from these computations are used, and possibly revised, at specific checkpoints in a feedback-control structure to meet the schedule and quality objectives. Two case studies were conducted to study the behavior of the proposed model. One study reported here uses data from a commercial project. The outcome from these two studies suggests that the proposed model might well be the first significant milestone along the road to a formal and practical theory of software process control. [ABSTRACT FROM AUTHOR]

As an application to active RC circuits in second-generation current conveyors (CCII), the simultaneous configuration of the lowpass, high-pass, bandpass, all-pass, and band-elimination filters (LPF, HPF, BPF, APF, BEF) is accomplished by changing the state variables in an arbitrary biquadratic transfer function. For BEF, a lowpass notch (LPN) filter (as a lowpass-type BEF) and a high-pass notch (HPN) filter (as a high-pass-type BEF) were obtained. The constructed circuits are made of five plus-type CCIIs and can be cascaded. The sensitivity of the passive components and the sensitivity to the voltage-transfer coefficient and current-transfer coefficient of the CCII are relatively small. Two types of filter circuits possible for simultaneous configuration are actually fabricated. For one of them, experimental results near 10 kHz, which is a relatively low frequency, are obtained and for the other, results near 100 kHz, a relatively high frequency, are obtained. In each case, the characteristics of the LPF, HPF, BPF, APF, BEF, as well as LPN and HPN, were obtained with Q of 0.7, 1.0, 5.0, and 10.0. In the APF, somewhat nonflat responses are observed near the pole frequency ωο depending on the setting of Q. This case was analyzed. Element sensitivity also was investigated. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 3, 80(1): 1–16, 1997 [ABSTRACT FROM AUTHOR]

This note points out a problem in the multi‐move sampler as proposed by Shephard & Pitt (1997) and provides an alternative correct formulation. [ABSTRACT FROM AUTHOR]

We assessed the potential rates of two microbial processes, cellulose decomposition potential (CDP) and hydrolytic activity, to explore the relationship of these functional measurements with several state variables of organic matter. Samples were collected from two interstitial sites in the main channel of the Rhone River and 10 sites on the alluvial floodplain representing five habitat types defined by sediment size (fine versus coarse sediments) and interstitial water origin (surface water versus groundwater). Although sites with fine sediments had more interstitial total organic matter, refractory and biodegradable dissolved organic carbon concentrations did not differ among habitat types. Unlike the floodplain, the main channel had high CDP andlow hydrolytic activity. In the floodplain, functional measurements varied consistently, and both CDP and hydrolytic activity were lowestat the sites with coarse sediments. Our data imply that microbially mediated processes are different in the main channel and the floodplain and that low levels of organic matter in the coarse sediments are probably due to slow rates of accrual rather than rapid rates of decomposition. Furthermore, the lack of correlation between functional variables and dissolved organic carbon concentrations illustrates the dangers of interpreting ecosystem processes or ecological integrity based solely on state variables. [ABSTRACT FROM AUTHOR]