The Influence of Single Parameter Changes on Subjective Experience and Ordering Performance of Electrotactile Cues

A cost sensitivity analysis for granular activated carbon using nine design parameters is presented. The cost analysis calculates the change in total annual plant cost for an equivalent percent change in each parameter value. This method is useful for preliminary cost estimates to predict how sensitive plant costs are to changes in design parameters, and to determine which parameters should be more closely evaluated in pilot plant work and final cost estimates.

This paper proposes an efficient algorithm for automatic and optimal tuning of pulse amplitude and width for sequential parameter estimation (SPE) of the neural membrane time constant and input-output (IO) curve parameters in closed-loop electromyography-guided (EMG-guided) controllable transcranial magnetic stimulation (cTMS). The proposed SPE is performed by administering a train of optimally tuned TMS pulses and updating the estimations until a stopping rule is satisfied or the maximum number of pulses is reached. The pulse amplitude is computed by the Fisher information maximization. The pulse width is chosen by maximizing a normalized depolarization factor, which is defined to separate the optimization and tuning of the pulse amplitude and width. The normalized depolarization factor maximization identifies the critical pulse width, which is an important parameter in the identifiability analysis, without any prior neurophysiological or anatomical knowledge of the neural membrane. The effectiveness of the proposed algorithm is evaluated through simulation. The results confirm satisfactory estimation of the membrane time constant and IO curve parameters for the simulation case. By defining the stopping rule based on the satisfaction of the convergence criterion with tolerance of 0.01 for 5 consecutive times for all parameters, the IO curve parameters are estimated with 52 TMS pulses, with absolute relative estimation errors (AREs) of less than 7%. The membrane time constant is estimated with 0.67% ARE, and the pulse width value tends to the critical pulse width with 0.16% ARE with 52 TMS pulses. The results confirm that the pulse width and amplitude can be tuned optimally and automatically to estimate the membrane time constant and IO curve parameters in real-time with closed-loop EMG-guided cTMS.

The purpose of this paper is to investigate the time periodic pulse electroosmotic flow (EOF) of Jeffreys fluids through a parallel plate microchannel. The driving mode of pulse EOF here is considered as a rectangle pulse. Using the method of Laplace transform, the analytical solution of velocity and volumetric flow rate of pulse EOF is derived. The effects of pertinent dimensionless parameters on the velocity and volumetric flow rate are discussed in detail. Results show that the pulse width is a valuable parameter for analyzing the influence of relaxation time and retardation time on magnitude of velocity and volumetric flow rate when the fluid flow reaches the steady state. Increasing the relaxation time reduces he magnitude of velocity and volumetric flow rate at low value pulse width , yet the trend is opposite for larger pulse width . The increase of retardation time will reduce the magnitude of velocity and volumetric flow rate no matter whether the value of pulse width is large or not. Furthermore, the frequency of velocity profile and volumetric flow rate is different because of the different pulse width . With the increase of pulse width , the different change frequency of velocity profile and volumetric flow rate slows down, which means a long cycle time. And as the relaxation time and pulse width grow, the time required for the fluid flow to reach a steady state will become longer. The conclusions have theoretical significance for biofluid based microfluidic transport systems driven by pulsed electric field.

Gain-switched short pulse generation from InAs-InP (1 1 3)B quantum dot laser excited state

A design parameter based update methodology for updating finite models based on the results of experimental dynamics tests is presented. In the proposed method, analyst-selected design parameters are updated with the objective of making realistic changes to a finite element model that will enable the model to more accurately predict the behavior of the structure. This process of 'reconciling' the finite element model with experimental data seeks to bring uncertainty in design parameters into the formulation for realistic updates of the model parameters. The reconciliation process becomes a problem of system identification. Since the finite element model is a spatial model, the high spatial density measurement of the structure's operating shape by the scanning laser-Doppler vibrometer is highly desirable. The reconciliation process updates the selected design parameters by solving a non-linear least-squares problem in which the differences between laser-based velocity measurements and analytically derived structural velocity fields are minimized over the entire structure. In the formulation, design or model parameters with greatest uncertainty are identified first, retaining statistical qualification on the estimates. This method lends itself to cross-validation of the model over the entire structure as well as at several frequencies of interest or over a frequency range. Model order analysis can also be performed within the process to ensure that the correct model is identified. The experimental velocity field is obtained by sinusoidally exciting the test structure at a given frequency and acquiring steady-state velocity data with a scanning laser-Doppler vibrometer. Conceptually, the laser-based measurements are samples of the structure's velocity field of operating shape. The finite element formulation used to generate the analytical steady-state velocity field is derived using either a dynamic stiffness finite element formulation or a static stiffness/mass matrix formulation. The emphasis on operating shapes is a key concept in the process, as it focuses reconciling the finite element model directly with the laser-based measurements. This process avoids the process of comparing mode shapes extracted from the experimental data with eigenvalues and eigenvectors extracted from the finite element model. Thus, the intermediate modal model is eliminated from the reconciliation process. Non-linear optimization algorithms such as sequential quadratic programming or the Nelder-Mead simplex method are used to perform the parameter updates. The ability to impose constraints on parameter changes is useful for keeping the parameters at reasonable values and for preserving system characteristics such as total structure mass. Statistical knowledge of the parameters could also be utilized in this context to penalize large changes from prior parameter estimates.

The performance of analog circuits can be severely degraded to the point of violating design specifications if care is not taken during the layout phase. The authors discuss the importance of the sensitivities of the performance functions with respect to design parameters in guiding the layout process. Sensitivities quantify the performance degradation induced by changes in different design and process parameters. Hence, critical parameters can be easily detected. In this way, the layout design can be controlled in order to avoid excessive changes in these parameters. This will reduce the iterative design process imposed by the standard manual techniques. A new definition for sensitivity which reflects the design constraints is given. The sensitivities are generated, reduced, and compiled in a weighted graph that can be used to control the placement algorithm. >

The article is devoted to the study of temperature errors of the string accelerometer used as part of a strapdown inertial unit. One of the main tasks facing the development of string accelerometers is the problem of compensating temperature effects to eliminate the resulting errors. One of the methods to solve such problems is to provide compensation for changes in the parameters of the string accelerometer, to level the appearance of the instrumental error in measuring the acceleration in the output signal of the device. On the prepared bench base at Scientific and Production Association of Measuring Technology (AO NPO IT) for setting up and conducting experiments, a study of string accelerometers, which are part of the strapdown inertial unit, was carried out. The study consisted of collecting output information from the device during its temperature calibration. During the experiment, the strapdown inertial unit was oriented in space so that its measuring axes of the accelerometer channels were directed alternately vertically upward or vertically downward with a smooth temperature change. The data obtained were analyzed to determine the dependence of the change in the initial vibration frequency of the string accelerometer and the design parameter of the accelerometer on the temperature in the operating temperature range of the device. An assessment of the possible level of efficiency of algorithmic compensation for changes in the accelerometer parameters was also shown. The studies carried out have shown the possibility, due to the algorithmic compensation of the temperature instrumental errors of one-component string accelerometers, to provide the accuracy requirements for the linear acceleration sensor channel of the strapdown inertial unit device in the operating temperature range. In particular, the use of algorithmic compensation for the temperature error of the initial frequency of the accelerometer f 0 reduced the absolute value of the parameter change by more than two orders of magnitude, and the maximum value of the error in approximating the change in the design parameter k from temperature is an order of magnitude less than the value before algorithmic compensation.

When considering digital displacement machines, one of the key elements are the fast switching valves. However, the dynamic requirements and conflicting design objectives mean that designing these fast-switching valves is a complex process, which pushes the technology to the limit. Optimization approaches are therefore required just to find feasible and, secondly, optimal solutions. However, dynamic CFD simulation is required to accurately describe dynamic fluid effects as fluid stiction, -drag and -end damping. This limits the possibilities to use optimization approaches due to the computational burden imposed, the need for dynamic mesh generation, and the design parameterization. Hence, this paper investigates analytical approximations and the error size introduced by simplifying dynamic fluid friction effects into a lumped parameter form. Specifically, the article presents a comprehensive parameter study of selected design parameters’ influence on the fluid forces in fast switching annulus valves, based on both analytical expressions and results derived from dynamic CFD simulations. The focus is primarily on describing the effects and size of the flow forces resulting from changes in parametric design parameters that influence the flow geometry. The results reveal a fair correlation between the fluid force predicted by the rapidly executable lumped model and the CFD model.

In this work, a multibody dynamics model of a wheeled mobile robot is developed to characterize the terrain reaction forces in terms of the physical and control parameters of the system. A common strategy for simulating the motion of mobile robots on soft soil is to compute the soil reaction forces using terramechanics models and to solve a forward dynamics problem by considering the soil reactions as a set of forces applied to the system. This intends to provide an accurate computation of the forces involved in the wheel-soil interaction; however, a series of factors such as the sensitivity of reaction forces to soil parameters limits the applicability of the existing terramechanics models in unstructured environments. We propose an alternative approach which does not rely on the soil properties, but at the same time does not intend to provide an exact computation of wheel-soil interaction forces. The main objective of this approach is to estimate the effect of changes in control and design parameters on the performance of the system, using the information provided by the dynamics model of the vehicle. To this end, the reaction forces for the wheel-terrain interaction in the ideal limit case of pure rolling and no penetration are obtained upon the specification of the motion at the contact points, via kinematic constraints. The validity of the analysis results obtained using the proposed paradigm is verified by simulation runs and experiments. The experimental results suggest that this approach is successful in predicting the variation of a set of important performance indicators in terms of the changes in the parameters of the system.

Abstract: Environmental problems are caused by climatic conditions and the results of sunlight entering buildings that cannot be controlled. Shading device become part of the building and interact directly with the environment and space in the building. Shading device can be applied to buildings to respond to environmental conditions such as solar radiation. Conditioning solar radiation entering buildings can be reduced to reduce building energy use. The results of this simulation show that the length (P) and angle (S) parameters have a significant positive effect on decreasing the intensity of solar radiation. Elements of the Horizontal Louvers type with a change in the value of the Angle (S) parameter from the basic design results in a decrease in radiation intensity of up to 44.3% when the angle changes to 150 with respect to the horizontal wall. In the Brise-Soleil Semi Façade With Louvers type, changing the value of the Length parameter (P) from the basic design results in a decrease in radiation intensity of up to 40.3% in the shading element with a length of 0.8 meters. On the other hand, changes in the distance parameter (J) of the shading element to the horizontal wall tend to increase the intensity of solar radiation. In the Horizontal Louvers type, the change in the parameter Distance (J) to the wall with a distance of 0.3 meters from the horizontal wall results in an increase in intensity of up to 81.1% when compared to the design basis.Keyword: Shading Device, Solar Radiation, Design Parameters, Vertical HousingAbstrak: Permasalahan lingkungan disebabkan oleh kondisi iklim dan akibat sinar matahari yang masuk ke bangunan yang tidak dapat dikendalikan. Perangkat peneduh menjadi bagian dari bangunan dan berinteraksi langsung dengan lingkungan dan ruang di dalam bangunan. Shading device dapat diterapkan pada bangunan untuk merespon kondisi lingkungan seperti radiasi matahari. Pengkondisian radiasi matahari yang masuk ke gedung dapat dikurangi untuk mengurangi penggunaan energi gedung. Hasil simulasi menunjukkan bahwa parameter panjang (P) dan sudut (S) berpengaruh positif signifikan terhadap penurunan intensitas penyinaran matahari. Elemen tipe Horizontal Louvers dengan perubahan nilai parameter Angle (S) dari desain dasar menghasilkan penurunan intensitas radiasi hingga 44,3% ketika sudut berubah menjadi 150 terhadap dinding horizontal. Pada tipe Brise-Soleil Semi Façade With Louvers, perubahan nilai parameter Length (P) dari basic design menghasilkan penurunan intensitas radiasi hingga 40,3% pada shading element dengan panjang 0,8 meter. Sebaliknya, perubahan parameter jarak (J) elemen peneduh ke dinding horizontal cenderung meningkatkan intensitas penyinaran matahari. Pada tipe Horizontal Louvers, perubahan parameter Jarak (J) ke dinding dengan jarak 0,3 meter dari dinding horizontal menghasilkan peningkatan intensitas hingga 81,1% jika dibandingkan dengan desain dasar.Kata Kunci: Elemen Pembayang, Radiasi Matahari, Parameter Desain, Hunian Vertikal

The issue of precision rotor systems regarding the relationship between their dissipative characteristics and changes in design parameters has been investigated. A dynamic model has been identified. The influence of parameter changes on the properties of the system has been studied and analyzed analytically. The sensitivity matrixand interparametric sensitivity have been determined. An analysis of the method of assessing changes in design parameters of a precision rotor system based on the deviation of the components of the phase coordinate vector has been carried out. Solving technological problems to ensure high quality of machines and devices, stability of their operating characteristics and vibration resistance during operation requires conducting research that is no less important than research related to the development of principles of operation, design and selection of parameters. One of the most promising areas for ensuring high performance and reliability of machines and devices is the development of methods of technical diagnostics. The application of the vibration diagnostics method is based on the presence of correlation dependencies of the dynamic characteristics of the entire assembly on the contact pressure in the connection due to a change in the stiffness of the joints. Changing the stiffness of individual elements leads to a change in the reduced stiffness of the assembly, and at the same time, the dynamic characteristics of the artificially created vibration field characteristic of it: frequencies and amplitudes of resonant oscillations, damping indicators, impedance and phase relations. Comparative analysis of these experimental data suggests the possibility of developing a method for assessing the technical condition of fixed contact joints of precision systems by changing their dynamic characteristics. The purpose of the article. The need to study and analyze the impact of parameter changes on the properties of the system analytically, that is, using a known mathematical model of the system. To solve the problem, the most acceptable methods are sensitivity theory. Sensitivity matrices allow us to determine the parameters that are sensitive and invariant to the state vector. This information answers the question of which parameters most determine the vibrational pattern of the object. In addition, determining the sensitivity matrix will allow us to significantly simplify the dynamic model of the system, leaving only those parameters that most determine the vibrational state of the system. In real objects, the mathematical model of which is determined by a system of linear differential equations, the connection of oscillations in different coordinates is characterized by the relationship of parameters. We will determine the parameters of the system, the change of which does not affect other parameters, but significantly affects the state vector of the system, the elements of which can be the values of vibration displacement, vibration velocity and vibration acceleration. We will solve the problem based on the joint consideration of two matrices: the sensitivity of the object and the interparametric sensitivity. Thus, for vibration diagnostics, the method of assessing changes in the design parameters of a precision rotor system by the deviation of the components of the phase coordinate vector (vibrational acceleration, velocity or vibration displacement amplitudes) will be the most obvious. Indeed, any, as small as possible, changes in the design elastic-inertial parameters of the system will necessarily be reflected in its amplitude-frequency characteristic. The effectiveness will depend on the accuracy of measurement of the components of the phase coordinate vector and on the absolute value of the sensitivity of their changes to changes in the design parameters. There is another side to the problem in setting the problem of vibration diagnostics of contact connections in precision instrument making. Determining the diagnosis of the conformity of the design quality should be carried out using a diagnostic system, which means the appropriate information and hardware support in solving this problem. To increase the accuracy and eliminate measurement errors, it is necessary to ensure full automation of the processes of vibration loads, vibration measurement of dynamic characteristics, efficiency and reliability of information and measuring systems. In this case, the most preferred are self-oscillating, including phase-resonant methods of perturbing mechanical vibrations. The use of microcomputer complexes will allow for express analysis to assess the quality of assembly of precision rotor systems directly in production conditions.

This paper considers single-degree-of-freedom, closed-loop linkages with a designated input angle and one design parameter. For a fixed value of the design parameter, a linkage has turning points (dead-input singularities), which break the motion curve into branches such that the motion along each branch can be driven monotonically from the input. As the design parameter changes, the number of branches and their connections, in short the topology of the motion curve, may change at certain critical points. As the design parameter changes, the turning points sweep out a curve we call the “turning curve,” and the critical points are the singularities in this curve with respect to the design parameter. The critical points have succinct geometric interpretations as transition linkages. We present a general method to compute the turning curve and its critical points. As an example, the method is used on a Stephenson II linkage. Additionally, the Stephenson III linkage is revisited where the input angle is able to rotate more than one revolution between singularities. This characteristic is associated with cusps on the turning point curve.

This paper presents a system modeling program, designed for use on a microcomputer, which calculates steady-state pressures and flowrates for a single-phase gas or water system. The program can model flow through 1) well completions using IPR formulas; 2) flow lines (inclined, vertical, or horizontal); 3) fixed orifice chokes; 4) and single- or multi-stage reciprocating compressors. The program uses nodes to identify pressures and node connecting elements to identify flowrates and determine which type of element that is being modeled. The program determines unknown pressures by either sequential or simultaneous methods. In the sequential method the program analyzes each node connecting element individually. The simultaneous solution creates a matrix containing flow balance equations from each node in the system. Next, the program solves this matrix simultaneously to determine values for the unknown pressures and flowrates. The purpose of this paper is to explain the logic of the modeling program and demonstrate its applicability in a microcomputer environment using examples.

The interval between stimulus and response is called reaction time. It measures the sensorimotor function and performance of an individual. It involves stimulus processing, decision making and response programming. Many factors such as age, gender, handedness, physical fitness, sleep, fatigue, distraction, personality type and type of stimulus have been shown to affect reaction time. Thus the aim of this study was to assess the effect of body mass index, handedness and gender on reaction time. A cross-sectional study was conducted in the Department of Physiology, Kathmandu University School of Medical Sciences, from October 2019 to December 2019, among 113 student volunteers. Height and weight were recorded and body mass index was then calculated. In ruler drop method, the students were made to sit with their forearm resting on a flat horizontal table surface, with their open hand at the edge of the surface. When the examiner suspended and released the ruler vertically the students were instructed to catch it as quickly as possible. Females had a faster reaction time than males when testing either hand (178.46±17.56 Vs 195.99±15.67; right hand) and (184.25±17.02 Vs 199.57±15.91; left hand). In females, right hand responded faster than left hand. In both gender, reaction time was faster in normal weight compared to overweight individuals but it was statistically insignificant. Females responded faster than males. Right hand had shorter reaction time than left hand in females. Reaction time was insignificantly prolonged in overweight individuals.

For large computational models, standard deterministic optimization approaches can be prohibitively expensive due to the need to repeatedly evaluate the model. This difficulty is amplified when stochastic aspects of the model are included, such as in reliability based design optimization. This work seeks to alleviate the computational costs of analyzing dynamic systems through employing a surrogate model in place of the full model analysis. The surrogate model of interest is a reduced-order model (ROM), which employs a Galerkin projection of the system response using a computed set of basis functions in order to significantly reduce the number of degrees of freedom in the system. The ROM techniques presented will not only be able to approximate the response accurately at the nominal design, with a significant reduction in computation cost, but will also estimate the response due to a change in design or uncertain variable parameters. Two conceptual approaches will be explored: extended reduced order modeling (EROM) and spanning reduced order modeling (SROM). The difference between these methods is an EROM approximates an updated basis (eigenmodes, singular vectors) for each change in parameters while an SROM uses a single spanning basis for the full parameter space. Different techniques for the computation of the EROM and SROM bases are explored, and the best of these methods are incorporated into the optimization and stochastic analysis of a structural problem, demonstrating the benefit of ROMs.