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This paper proposes a new method to improve re performance of intra-field interpolation which is the mos~ important element of deinterlacing method. Traditional edge- based methods were poor at determining accurate edge iirection which decides interpolation performance. The 7roposed method decides the direction and slope of edge based on locally adaptive-thresholded binary image to mprove efficiency and accuracy, and it also increased the ~orizontal size of search window to 15 for better direction ietermination at gentle slope. Compared to traditional edge- based methods, interpolation based on binary image, which is ,`enerated using the proposed method, leads to great erformance improvement. With computer simulations for a ~`ariety of images, this paper shows the new approach is much ~etter than traditional methods.. [ABSTRACT FROM AUTHOR]

This paper presents an implementation of an ~daptive beamformer in a hands-free unit. The proposec~ ~daptive beamformer suppresses stationary noise an~ nterference sound. The adaptive beamformer and acoustic `cho canceller were implemented in a compact hands-free mit with a low-cost DSP. Experimental results demonstrate he noise reduction performance of the hands-free unit'. [ABSTRACT FROM AUTHOR]

The article offers information on the publication of "IEEE Transactions on Computational Social System" and topics covered under the publication which include modeling, simulation and understanding of social system from computational perspectives. The article covered in the publication include social network dynamics, social intelligence and cognition, and computational behavior modeling.

In this paper, characteristic model-based modeling and control approaches for complex dynamical networks based on sampled data are studied. It shows that the characteristic model, in which underline network topological structures are simplified, can provide a straightforward and implicit description for network dynamics. The induced parameter estimation method can further make the model adaptive and purely data-driven. Moreover, a control law based on this model is also proposed to govern the network dynamics. Finally, the theoretical results are verified through numerical simulations of modeling and stabilizing a dynamical network. [ABSTRACT FROM AUTHOR]

How animals navigate in their cross-continental migration has puzzled scientists for centuries. To date, the mechanism behind this mysterious navigation remains unclear. In this paper, a hypothesis is developed and computer simulations have been performed to investigate long-distance animal navigation. Simulation results show that animals may be able to complete their long-distance navigation by observing a spatial angle included by the geomagnetic field line and a geographic direction, without necessarily knowing any prior landmark information. Our results not only match existing observation reports in detail on the long-distance migration routes of animals, but also are able to explain the conflicting evidence on the role of geomagnetic field in animal navigation. We think our results could help reveal the actual mechanism of animal navigation. This paper also provides a potential solution for global and local area navigation of mankind and machines assisted by artificial sensors. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new clustered structure for a multiway relay network (MWRN) with $G$ clusters, $N$ users per cluster, one intracluster relay per cluster, and a single intercluster relay. The proposed structure allows private information exchange among users within a certain cluster through the corresponding intracluster relay and only public information exchange among users in different clusters through the intercluster relay. In this paper, we quantify the dominating error events in the proposed clustered MWRN and derive the expressions for the probability of these error events. Then, we use these expressions to derive the average bit error rate (BER) of a clustered MWRN. It is shown that clustering in an MWRN improves the error performance by reducing the number of dominating error events and, in effect, reducing error propagation, compared with the nonclustered counterpart. The analysis proves that the average BER of a clustered MWRN is minimized when the number of clusters and the number of users per cluster are chosen to be the closest possible factors of the total number of users, i.e., $L=GN$. Finally, numerical simulation results are provided to verify the validity of the analysis. [ABSTRACT FROM AUTHOR]

This paper proposes a novel finite-memory (FM) estimation method for vehicle roll and road bank angles. We consider a three-degree-of-freedom model based on bicycle and vehicle roll models, where there exist uncertainties in the model parameters. The existing estimation methods may show poor performance for the considered model with uncertainties. The accumulated errors, which might be caused by modeling uncertainties and numerical errors, may degrade the performance of existing methods because they use all past measurements. To overcome the weaknesses of the existing methods, a new FM estimation method is proposed and can prevent accumulated errors by using recent finite measurements. Both the simulation and experimental results show that the proposed estimation method ensures more reliable and accurate performance than the existing methods under various driving conditions. [ABSTRACT FROM AUTHOR]

To improve the interception performance in missile guidance applications, this paper proposes a novel control strategy for the integrated guidance and control design subject to input constraints. The system constraints are translated into a restriction in an invariant set, which is then enforced by manipulating the derivative of the applied reference. For the integrated system in the presence of disturbances and parametric uncertainties, disturbance observers are applied to estimate the lumped disturbances existing in each loop. The quadratic stability via dynamic surface control is guaranteed, and an ellipsoidal approximation of the invariant set is obtained, which can be enlarged to allow some degree of the input saturation. The effectiveness of the proposed scheme is illustrated using numerical simulations against a maneuvering target. [ABSTRACT FROM AUTHOR]

Real-time globally consistent camera localization is critical for visual simultaneous localization and mapping (SLAM) applications. Regardless the popularity of high efficient pose graph optimization as a backend in SLAM, its deficiency in accuracy can hardly benefit the reconstruction application. An alternative solution for the sake of high accuracy would be global registration, which minimizes the alignment error of all the corresponding observations, yet suffers from high complexity due to the tremendous observations that need to be considered. In this paper, we start by analyzing the complexity bottleneck of global point cloud registration problem, i.e., each observation (three-dimensional point feature) has to be linearized based on its local coordinate (camera poses), which however is nonlinear and dynamically changing, resulting in extensive computation during optimization. We further prove that such nonlinearity can be decoupled into linear component (feature position) and nonlinear components (camera poses), where the former linear one can be effectively represented by its compact second-order statistics, while the latter nonlinear one merely requires six degrees of freedom for each camera pose. Benefiting from the decoupled representation, the complexity can be significantly reduced without sacrifice in accuracy. Experiments show that the proposed algorithm achieves globally consistent pose estimation in real-time via CPU computing, and owns comparable accuracy as state-of-the-art that use GPU computing, enabling the practical usage of globally consistent RGB-D SLAM on highly computationally constrained devices. [ABSTRACT FROM AUTHOR]

With the development of science technology, ferrofluid seal has been intensively applied in mechanical industry, but more and more larger sealing stages are needed. At present, the literature mostly concentrated on numerical analysis with few pole pieces ferrofluid seals and focused on the critical pressure value in one-stage magnetic fluid seal, lacking of numerical simulation and experimental validation on the static pressure of multi-stage ferrofluid seals. On this basis, the analysis of larger number of sealing stages is presented. And numerical simulation along with experiment investigation was used to study the seal capacity of ferrofluids in different seal gaps and different seal stages in this paper. The results show that the theoretical value is well coincident with experimental value when the sealing gap is less than 0.2 mm. Increase the number of the pole tooth can significantly improve the seal capacity of ferrofluid seal, but the sealing pressure of ferrofluids does not increase linearly with the addition of the number of pole teeth. For the new structure, the pressure of one-stage pole tooth has more than doubled as the sealing clearance is 0.2 mm and 3.5 times increase when the sealing gap is 0.3 mm. [ABSTRACT FROM AUTHOR]

This paper investigates the control design approach for perching maneuvers of fixed-wing aircraft in the presence of both initial deviations and mismatched disturbances. The highly nonlinear longitudinal dynamics is transformed into a piecewise linear model. A disturbance observer is designed and a piecewise linear controller using the estimates of disturbances is constructed. System stability and disturbance attenuation are analyzed theoretically. Simulation results demonstrate the effectiveness of the proposed control approach. [ABSTRACT FROM AUTHOR]

This paper presents a quasi-static surface-based partial element equivalent circuit (PEEC) model for electromagnetic problems consisting of coupled conductors and heterogeneous dielectrics of finite size. The PEEC model is based on the surface equivalent principle. Unlike the traditional surface-based PEEC models, in which the integral equations are set up by enforcing the field continuity in the true field region, the homogeneous integral equations in this model are obtained by enforcing the tangential null field condition in the null field regions. Simplified integral equations are obtained under the quasi-static assumption, in which the circuit elements carrying electric currents and magnetic charges on the dielectric surfaces are vanished. Consequently, the size of the subcircuit describing dielectrics is reduced significantly compared to the full-wave surface-PEEC (S-PEEC) model. Since the quasi-static S-PEEC model only contains frequency-independent circuit elements, it can be conveniently used for time-domain simulation. Three numerical examples are presented to validate the new PEEC model for typical embedded RF passive components, packaging and interconnection problems in both the frequency domain and the time domain. Excellent agreement is observed between the results of the proposed PEEC model, S-PEEC model, and those of commercial software within the quasi-static frequency range. [ABSTRACT FROM AUTHOR]

Fast-growing interests in safe and effective robot–environment interactions stimulated global investigations on soft robotics. The inherent compliance of soft robots ensures promising safety features but drastically reduces force capability, thereby complicating system modeling and control. To tackle these limitations, a soft robotic joint with enhanced strength, servo performance, and impact behavior shaping is proposed in this paper, based on novel three-dimensional-printed soft origami rotary actuators. The complete workflow is presented from the concept of origami design and analytical modeling, joint design, fabrication, control, and validation experiments. The proposed approach facilitates a fully customizable joint design towards the desired force capability and motion range. Validation results from models and experiments using multiple fabricated prototypes proved the excellent performance linearity and superior force capability, with 18.5-N·m maximum torque under 180 kPa, and 300-g self-weight. The behavior shaping capability is achieved by a low-level joint-angle servo and a high-level variable-stiffness regulation; this significantly reduces the impact torque by 53% and ensures powerful and safe interactions. The comprehensive guidelines provide insightful references for soft robotic design for wider robotic applications. [ABSTRACT FROM AUTHOR]

This paper studies the automatic carrier landing control problem of aircrafts with the system dynamics of nonlinearity and multivariable coupling, by applying preview control scheme. An automatic carrier landing system is developed, including a particle filtering based flight deck motion prediction, a corrected reference glide slope generation and an integrated guidance and control modules. A preview control algorithm is presented to guarantee the optimal tracking performance, and simulations demonstrate the better carrier landing performance under the deck motion and airwake disturbances, comparing with the proportional–integral–derivative control scheme. [ABSTRACT FROM AUTHOR]

The trigger circuitry is critical for trace-based post-silicon debug, which detects specified events or event sequences to initiate or stop the tracing. In this paper, we propose a resource efficient trigger design for the post-silicon debug which integrates several different detection schemes to improve the detect ability. The design reuses the trace buffer to store the trigger set for event detection or store the transitions of the generated finite state machine for event sequence detection, which converts the trigger detection into simple read operations to the trace buffer and equality matching operations. Simulation and emulation are both used to validate the usability of the design. In comparison with the prior trigger circuits with the same trigger width, the proposed method provides much more powerful detect ability and configurability for complicated trigger conditions, and needs lower area overhead. [ABSTRACT FROM AUTHOR]

This paper presents a new reliability-based incremental phasor measurement unit (PMU) placement method via an enumeration-based integer linear programming optimization approach. By evaluating the proposed reliability indices for node and system observability, incremental PMUs are sequentially placed on the locations where the reliability of entire system's observability can be best improved at each step. As a result, a pre-set desired reliability of the system's observability can be achieved while using the minimal number of PMUs. The proposed method is generic and flexible in a way that different kinds of failures that impact the reliability of system observability can be easily included in the method. The 1st-order and 2nd-order failures of PMUs and lines are considered in this paper. The proposed method is validated using a 4-node system, the IEEE 14-node system and the IEEE RTS 96 test system. Simulation results show that the proposed method is effective and efficient in enhancing the reliability of observability for any system regardless of what the initial PMU placement of the system may be. [ABSTRACT FROM AUTHOR]

Because the coefficient matrix is dense in the electromagnetic-field-analysis models of coated conductors using current vector potentials, the analyses of large-scale coils require a large amount of memory and long computation time. In this paper, we introduce hierarchical matrices by using the HACApK library in order to reduce both memory consumption and computation time. The effect of the method with respect to memory consumption and computation time is examined in numerical tests using a pancake coil wound with a coated conductor. The effect of parallel computations is also examined. Finally, we analyzed a large-scale magnet, with 1.5 million unknown values. [ABSTRACT FROM AUTHOR]

In the framework of the project where space in a cryostat is strictly limited, the high temperature superconductor (HTS) segments of the current leads have to be placed horizontally and in a scattered magnetic field. We developed the current leads optimization model for such conditions. In this paper, we present the results of optimization for 2000AHTS current leads, comprised of 2G HTS tapes and able to work in the magnetic field up to 2 T. The optimal parameters of the current leads segments have been determined using a numerical simulation. In order to approach the maximum efficiency, it is necessary to have a very good heat exchange between the current leads and evaporating helium gas. The impact of the external magnetic field on the heat leak from current leads into liquid helium is studied. [ABSTRACT FROM AUTHOR]

Magnetic resonance electrical property tomography (MR-EPT) has significant potential for the estimation of the electrical properties (EPs) of tissue, which are essential for the calculation of specific absorption rates (SAR), a critical safety factor requiring monitoring and controlling in applications of ultrahigh field magnetic resonance imaging. In this paper, a novel, efficient method based on integral equations is proposed for the calculation of the EPs and the RF-coil-induced \boldsymbolB\boldsymbol{z} field. An inverse problem framework is first constructed to include the forward problem operator, while the EPs are reconstructed by using a nonlinear conjugate gradient method. The RF-coil-induced \boldsymbolB\boldsymbol{z} component is then calculated based on the achieved EPs and the forward operator. The proposed MR-EPT algorithm improves upon and differs from the existing methods in three aspects. First, a three-dimensional algorithm with improved efficiency is proposed. The higher efficiency arises from using a fast integral equation solver as well as an approximation of initial solution. Second, in addition to the EP values, the proposed method calculates the RF-coil-induced \boldsymbolB\boldsymbol{z} component, which is usually neglected in the existing MR-EPT algorithms. Here, we show that considering this \boldsymbolB\boldsymbol{z} field can significantly improve the accuracy of the SAR calculation. Finally, in contrast to differential approaches, the proposed method is more robust against noisy measurement of the transmit magnetic fields, because of the nature of the integral equations. The proposed method is verified through a full-wave simulation and an anatomically accurate numerical brain model, demonstrating its accuracy and efficiency. [ABSTRACT FROM AUTHOR]

This paper proposes an iterative learning control (ILC) scheme for a dual-mode flyback inverter operating in both discontinuous conduction mode (DCM) and continuous conduction mode (CCM). In dealing with more than 200-W power applications, the dual-mode flyback inverter takes advantage of both DCM and CCM operations. However, it is difficult to control the output current because the system gain is quite low in DCM and the system transfer function has a right-half plane zero in CCM. To overcome the problems occurring in DCM and CCM operations, we propose an ILC scheme with multiple phase-lead compensation. The ILC is proposed to achieve accurate reference tracking and to reject periodic disturbances. The multiple phase-lead compensation technique is then employed to compensate for the effect of different system dynamics. As a theoretical result, we derive the asymptotic stability of the closed-loop system. We also performed the numerical simulations and experimental tests to validate the proposed control approach. [ABSTRACT FROM AUTHOR]

This paper describes the development of a modern power system laboratory within a Bologna Declaration compliant curriculum at the Department of Energy and Power Systems, Faculty of Electrical Engineering and Computing, University of Zagreb. The paper describes laboratory components and provides insight into the experiments that students are required to perform. The laboratory course is divided into three major components: power system simulations, computer simulations and high voltage. Power system simulations are performed on a miniature real-world power system that can be synchronized to the actual power system. Computer simulations are performed both on commercially available software solutions commonly used by power utilities and consulting companies, and on software tools developed at the Department of Energy and Power Systems. High voltage exercises are performed in the High Voltage Laboratory, where students are familiarized with high voltage phenomena. Results of student questionnaires collected over the previous four years are analyzed. This feedback, together with industry experts' observations and suggestions, provides the basis for improvements that are constantly introduced. [ABSTRACT FROM PUBLISHER]

This paper presents a methodology for modeling the deployment of implantable devices used in minimally invasive vascular interventions. Motivated by the clinical need to perform preinterventional rehearsals of a stent deployment, we have developed methods enabling virtual device placement inside arteries, under the constraint of real-time application. This requirement of rapid execution narrowed down the search for a suitable method to the concept of a dynamic mesh. Inspired by the idea of a mesh of springs, we have found a novel way to apply it to stent modeling. The experiments conducted in this paper investigate properties of the stent models based on three different spring types: lineal, semitorsional, and torsional springs. Furthermore, this paper compares the results of various deployment scenarios for two different classes of devices: a stent graft and a flow diverter. The presented results can be of a high-potential clinical value, enabling the predictive evaluation of the outcome of a stent deployment treatment. [ABSTRACT FROM PUBLISHER]

For the simulation of the human exposure to magnetoquasi-static fields of inductive power transfer (IPT) systems two domain decomposition methods—the coupled scaled-frequency finite-difference time-domain (SF-FDTD) method and the co-simulation SF-FDTD method—are presented in this paper. Using both Huygens’ principle and the SF-FDTD method, a two-step approach is developed resulting in two different simulation schemes, the coupled SF-FDTD method and the co-simulation SF-FDTD method, respectively. These two-step schemes are able to replace high-dimensional monolithic exposure simulation models by problems of smaller size with less computer memory demand. An exposure scenario, including an IPT system, a car, and a high-resolution human body voxel model, is modeled and simulated using both methods. A full-scale monolithic SF-FDTD simulation is used as reference and its results—i.e., the body-internal electric field strengths—are compared with the results of the presented two-step methods. The maximum of the body-internal electric field strength (voxel average) is determined and compared to basic restrictions given by the international commission on nonionizing radiation protection. [ABSTRACT FROM AUTHOR]

Charge accumulation on a solid insulator surface is one of the critical factors for the development of dc gas-insulated equipment since it will lead to the overstress of polymeric insulation due to local field distortion and enhancement. Therefore, it is important to study the charge accumulation phenomenon on spacer surface under dc field. For decades, researchers have made tremendous progress on this subject by measurement and simulation. However, measurement results are quite different by different researchers due to various electrode configurations and experimental conditions. Further, most researchers use potential to represent charge density, which is not rigorous in that many charge density distribution details are hidden behind the potential. As for pure numerical simulation, reports are rather academic and sometimes cannot accord with the real fact. In this paper, attempts are made to characterize the charge accumulation patterns on spacer surface in HVDC gas-insulated system. Surface charge distributions on a model GIL spacer in 0.1 MPa air under DC voltage are obtained by an advanced measurement method, from which the dominant uniform charging pattern and random charge speckles are separated. Mechanism responsible for the dominant uniform charging pattern is discussed with the aid of a simulation model. Results indicate that, in a well-cleaned system, the electric current through the spacer bulk is the principal factor, but gas conduction is not negligible due to some inevitable ion sources. Highly localized pockets of charge are also observed, which are referred to as speckles. They may originate from micro discharges due to tiny metal particles on the spacer surface or microscopic protrusions on the electrodes. [ABSTRACT FROM PUBLISHER]

This paper investigates the performance of a cognitive hybrid satellite–terrestrial network, where the primary satellite communication network and the secondary terrestrial mobile network coexist, provided that the interference temperature constraint is satisfied. By using the Meijer-G functions, the exact closed-form expression of the outage probability (OP) for the secondary network is first derived. Then, the asymptotic result in a high-signal-to-noise-ratio (SNR) regime is presented to reveal the diversity order and coding gain of the considered system. Finally, computer simulations are carried out to confirm the theoretical results and reveal that a more loose interference constraint or heavier shadowing severity of a satellite interference link leads to a reduced OP, whereas stronger satellite interference power poses a detrimental effect on the outage performance. [ABSTRACT FROM AUTHOR]

Various methods have been proposed for monitoring continuously varying event-region scenarios using wireless sensor networks (WSNs). However, these methods use either a centralized approach, in which a powerful control center is used to reconstruct the entire random field, or a semi-centralized approach, in which extensive real-value data exchange takes place among the sensors. By contrast, this paper proposes a two-phase distributed dynamic event-region detection scheme for WSNs characterized by a space-time Markov random field with a particular Gibbs distribution. In Phase I of the proposed scheme, each sensor makes an initial decision in accordance with its current Gaussian corrupted observation and previous decision. In Phase II, the nodes update their decisions based on the decision information received from their neighbors. Notably, the proposed scheme has a low-communication-rate characteristic, and is thus ideally suited to WSN applications. The performance of the proposed scheme is compared with that of a semicentralized detection scheme by means of computer simulations. [ABSTRACT FROM PUBLISHER]

We consider multi-source energy harvesting communication systems, where the energy harvested from two independent processes is used for the transmission of the data packets. The data packets arrive randomly and wait in a queue for accumulation of sufficient energy and for service completion of previously arrived packets. Thus, the data queue dynamics are influenced jointly by the energy arrival process, the data arrival process, and the data service process. This coupling between the data and energy queues makes an exact system analysis extremely hard, and has led researchers to resort to either computationally intensive numerical solutions or to make simplifying approximations. In this paper, we employ Diphase, a two phase queueing formulation, which decouples the wait stages for the energy arrival process and the service process, to derive closed-form expressions for the average packet delay and the probability of data packet loss due to buffer overflow. These expressions are shown to be exact when the service time is negligible, and robust for a relatively wide range of values of the average service time. We show that these expressions are useful in selecting system design parameters, which maximize the throughput while meeting the required quality of service constraints. [ABSTRACT FROM PUBLISHER]

Numerical simulation of anechoic chambers is an important topic nowadays, since it can provide useful data about the performance of an electromagnetic compatibility site. However, the mathematical nature of the problem, the physical dimensions of the simulated sites, and the frequency ranges pose nontrivial challenges to the numerical simulation. Computational requirements, in particular, will quickly become unmanageable if adequate techniques are not employed. In this paper, we describe a novel approach, based on equivalent elements, that enables the simulation of large chambers with modest computational resources. The method is then validated against 558 real measurement results. [ABSTRACT FROM AUTHOR]

In this paper, we consider a noncoherent amplify-and-forward (AF) half-duplex cooperative relay system, where the channel gains are completely unknown at the destination. For such a system, the currently available design of noncoherent unitary space-time block codes for the multiple-input—multiple-output (MIMO) systems cannot be applied because of the signal matrix having a certain triangular structure. In this paper, we propose the design of full-diversity nonunitary and unitary diagonal distributed space-time block codes for the noncoherent AF half-duplex protocol. We prove that both the nonunitary and unitary codes enable the unique identification of the channel and transmitted signals in the noise-free case for any given nonzero received signals, as well as full noncoherent diversity in the noise case for the least square error (LSE) receiver. Computer simulations show that our unitary code obtains about 5-dB signal-to-noise-ratio (SNR) gains at the symbol error rate of 10^-5 over the precoded training scheme and the differential coding scheme. [ABSTRACT FROM PUBLISHER]

In this paper, we propose a new rewiring approach for distribution networks called randomized local rewiring (RLR). We evaluate the robustness of original and rewired distribution networks using new metrics and show that the choice of a network topology can affect its robustness considerably. Some supply and distribution networks exhibit characteristics similar to those of scale-free networks. Simulation results show that applying RLR to such distribution networks can improve the network robustness on the supply availability and network connectivity metrics when both random and targeted disruptions are likely to occur. A unique feature of our model is a tunable rewiring parameter, which makes it possible to design networks with the same performance on the supply availability, network connectivity, and average delivery efficiency metrics in the presence of both types of disruptions. This paper will describe the robustness metrics and the new approach, illustrate the experimental results in the context of a military logistic and a retailer’s distribution network, and discuss the insights gained about choosing the right topology for achieving higher robustness. [ABSTRACT FROM PUBLISHER]

This paper proposes a simple and novel method of designing and developing high-linearity linear variable differential transformer (LVDT)-based displacement sensing systems. Conventionally, precise adjustment of windings is made to enhance the linearity range of LVDTs. The tedious job of pitch adjustment of windings of LVDTs can be overcome by using the proposed method. A functional link artificial neural network has been successfully used in this paper for nonlinear compensation of the LVDT. The effectiveness of the proposed method is demonstrated through computer simulation with the experimental data of two different LVDT. The complete algorithm with the practical setup for the development of a linear LVDT is presented in this paper. [ABSTRACT FROM AUTHOR]

Integrated Systems Health Management (ISHM) consists of processes managing erroneous conditions that systems may encounter during their operational life by either designing out failures early on or defending and mitigating any possible failures. A successful implementation of ISHM consists of the following four components: data sensors, computations, data sinks, and visualization modules. In this paper, we explore the use of virtual reality (VR) platforms as a candidate for developing ISHM visualization modules. VR allows for a complete and spatially accurate 3-D model of a system to be displayed in real time. It provides a medium for improved data assimilation and analysis through its core tenants of immersion, interaction, and navigation. Furthermore, VR allows for integrating graphical, functional, and measurement data in the same platform-providing for the development of subsequent risk-analysis modules. The research objectives of this paper are focused on creating a detailed visual model of a multisensor rocket engine test facility inside a VR platform and demonstrating the capability of the VR platform in integrating graphical, measurement, and health data in an immersive, navigable, and interactive manner. A human-based performance evaluation of the VR platform is also presented. These research objectives are addressed using an example of a multisensor rocket-engine portable test stand at the National Aeronautics and Space Administration (NASA) Stennis Space Center's E-3 test facility. [ABSTRACT FROM AUTHOR]

Multiple-input-multiple-output (MIMO) receivers with direct-conversion radio-frequency (RF) architecture are investigated in this paper. Direct conversion is a low-cost RF design that requires fewer external components in chip implementation. Nevertheless, it introduces extra RF impairments such as I-Q imbalance and dc offset in addition to frequency offset that is commonly encountered in all RF architectures. This paper proposes to do the joint least squares (LS) estimation of frequency, dc offset, I-Q imbalance, and a channel in MIMO receivers to improve performance; frequency-dependent and frequency-independent I-Q imbalances are included. Previously, RF impairments were separately estimated in MIMO receivers, which leads to inferior performance. In particular, a receiver architecture that facilitates the joint estimation of the frequency, the dc offset, the I-Q imbalance, and the channel is proposed. The LS criterion is then applied to obtain the joint estimators, with a special training-sequence design to reduce complexity. Simplified estimators on the frequency and dc offset are also proposed with almost no loss in performance. Finally, the estimators are shown through analysis to be unbiased and approach the Cramér-Rao lower bound (CRLB) for signal-to-noise ratios (SNRs) of interest. The analysis is verified by computer simulations. [ABSTRACT FROM AUTHOR]

This paper presents a novel initial value compensation (IVC) using an additional input for semi-closed control systems. The authors have already proposed the IVC approach using the additional input for residual vibration suppression in the fast and precise positioning control. In the approach, however, an essential subject has remained, i.e., the positioning control in the load side could not satisfy the required performance because the systems have been constructed under the assumption of a semi-closed control system. An improvement of the control performance in load position, therefore, is discussed in this paper, where the appropriate assignments of poles and zeros in IVC are ensured, considering the transfer functions of position in both sensor and load for the control initial values. The effectiveness of the proposed approach has been verified by numerical simulations and experiments using a prototype. [ABSTRACT FROM AUTHOR]

The interplay between decision-making and decision-support tools has proven puzzling for many years. One of the most popular decision-support tools, what-if analysis, is no exception. Decades of empirical studies have found positive, negative, and null effects. In this paper, we contrast the marginal-analysis decision-making strategy enabled by what-if with the anchoring and adjustment decision-making strategies prevalent among unaided decision makers. By using an aggregate production planning decision task, we develop a Monte Carlo simulation to model 1000 independent what-if decision-making episodes across a myriad of conditions. Results mirror and explain seemingly contradictory findings across multiple prior experiments. Thus, this paper formalizes a simulation approach that expands the scope of previous findings regarding unaided versus what-if analysis aided decision making and suggests that relative performance is quite sensitive to task conditions. In this light, then, performance effect differences in past research are to be expected. While our analysis involves a single task context, the larger and more important point is that, even within a single task context, performance differences between unaided and aided decision making are emergent. [ABSTRACT FROM AUTHOR]

This paper describes methods and issues related to interfacing electromagnetic transient simulation programs with general mathematical algorithms, which are either custom-developed by the user or are available through other mathematical analysis platforms. Various interfacing types and techniques are described along with potential areas of application. Implementation methods are detailed for each type of interface as well. This paper presents several interfacing examples from a wide variety of applications, including advanced switching schemes for power converters and controller implementation. [ABSTRACT FROM AUTHOR]

This paper presents an integrated model for recognizing power-quality disturbances (PQD) using a novel wavelet multiclass support vector machine (WMSVM). The so-called support vector machine (SVM) is an effective classification tool. It is deemed to process binary classification problems. This paper combined linear SVM and the disturbances-versus-normal approach to form the multiclass SVM which is capable of processing multiple classification problems. Various disturbance events were tested for WMSVM and the wavelet-based multilayer-perceptron neural network was used for comparison. A simplified network architecture and shortened processing time can be seen for WMSVM. [ABSTRACT FROM AUTHOR]

In this paper a detailed description, an analysis, and an assessment of a frequency-domain technique highly applicable to power systems transient analysis (i.e., the numerical Laplace transform) are presented. The errors due to truncation and sampling when converting a frequency-domain signal to the time domain are analyzed. Additionally, the use of odd and regular sampling is discussed. Two major goals of the paper are the revival of the mentioned technique and its friendly description for power systems engineers. As an application, a transmission-line transient is presented. [ABSTRACT FROM AUTHOR]

Due to their ability to provide reactive power support and control active power flow, voltage-sourced-converter (VSC)-based flexible ac transmission system controllers can be used to improve the power transfer capability of congested transmission lines. A converter-based controller structure has the inherent feature to be used to provide shunt or series compensations. This inherent feature is utilized in the convertible static compensator installed at the New York Power Authority's Marcy substation, which can operate in 11 configurations of shunt and series compensations. Moreover, each configuration can be operated in different control modes. The paper presents a novel approach to model converter-based transmission controllers for load-flow calculations. The paper focuses on modeling converter-based controllers when two or more VSCs are coupled to a dc link (e.g., unified power-flow controller (UPFC), interline power-flow controller, and a generalized unified power-flow controller). This approach also allows efficient implementation of various VSC operating limits, where one or more VSCs are loaded to their rated capacity. A computer program incorporating this approach is developed to illustrate the maximum dispatchability of UPFC and IPFC in a large power system. [ABSTRACT FROM AUTHOR]

This paper presents the method for taking into consideration the influence of metallic installations surrounding the feeding line on the ground fault current distribution in supplied substations. When a ground fault occurs in a substation supplied by a cable line, these installations can significantly participate in reducing the part of the ground fault current emanating through the grounding system of this substation into the surrounding earth. Since only this part of the ground fault current creates potentials on the grounding system, this also means the reduction of all potential differences (touch and step voltages) appearing during the ground fault inside and in the vicinity of the supplied substation. However, current analytical expressions for the determination of the cable line reduction factor do not take into consideration this favorable effect. It is also not possible to determine it by direct measurements. This paper presents a method which enables us to achieve this by using the results of reduction factor measurements and by modeling surrounding metallic installations as a single equivalent conductor, cylindrical in form and parallel with the cable line. [ABSTRACT FROM AUTHOR]

This paper presents the output power control of a wind energy conversion system (WECS) based on a permanent magnet synchronous generator (PMSG). It is assumed that the considered wind module integrates a stand-alone hybrid generation system, jointly with a battery bank, a variable ac load, and other generation subsystems. The operation strategy of the hybrid system determines two possible operation modes for the WECS, depending on the power requirements of the load and the wind availability. The paper deals with the design of a combined high- order sliding mode (HOSM) controller for the power control of the WECS on both operational modes. The main features of the obtained controller are its chattering-free behavior, its finite-time reaching phase, its simplicity, and its robustness with respect to external disturbances and unmodeled dynamics. The performance of the closed-loop system is assessed through representative computer simulations. [ABSTRACT FROM AUTHOR]

This paper provides the analytical equation for the charge collection from a collecting region with a finite dimension. Electron-beam-induced current has widely been used for semiconductor characterization. The availability of analytical expressions would further enhance the study and development of various measurement techniques. Nevertheless, most devices are fabricated with junctions that have finite dimensions, which are usually either L shaped or U shaped. For these cases, the analytical expressions are lacking. This paper provides the derivation of the electric current profile when an electron beam scans from within the collecting region for these two cases. The computation was verified with a semiconductor device simulation program on a computer and was found to be in good agreement. This paper then gives a discussion on the effects of certain parameters such as the junction depth and junction width, the diffusion length, and the depth of the generation volume. [ABSTRACT FROM AUTHOR]

This paper presents research on the modeling of the design of measuring systems (MS) with time-limited data flow. A new method of describing the MS model based on Petri Nets (PNs) and the Colored PN Tools environment is proposed. This paper provides an overall description of the formal and informal methods that can be used while designing systems. [ABSTRACT FROM AUTHOR]

In this paper, the stability of n-channel 4H-silicon carbide (SiC) DMOSFETs with junction termination extension (JTE) was assessed by measuring the breakdown voltage (BV) of these devices before and after bias stress at a high temperature. The BY slumped after the DMOSFET was bias stressed at 1200 V for 2 hat 175 °C, and the slumped BY dynamically recovered to the prestress value during the poststress period. Computer simulation suggests that the BV slump and its recovery are dominated by the positive charge trapping/detrapping phenomena at the SiC/field oxide interface in the JTE structure, rather than the trapping/detrapping at the SiC/gate oxide interface in the cell structure. A positive interface charge of approximately one-third of the sheet dopant concentration of the JTE region, lowers BV by 150 V, which is the typical measured BY slump of the DMOSFETs of this paper. [ABSTRACT FROM AUTHOR]

Ablation strategies to prevent episodes of paroxysmal atrial fibrillation (AF) have been subject to many clinical studies. The issues mainly concern pattern and transmurality of the lesions. This paper investigates ten different ablation strategies on a multilayered 3-D anatomical model of the atria with respect to 23 different setups of AF initiation in a biophysical computer model. There were 495 simulations carried out showing that circumferential lesions around the pulmonary veins (PVs) yield the highest success rate if at least two additional linear lesions are carried out. The findings compare with clinical studies as well as with other computer simulations. The anatomy and the setup of ectopic beats play an important role in the initiation and maintenance of AF as well as the resulting therapy. The computer model presented in this paper is a suitable tool to investigate different ablation strategies. By including individual patient anatomy and electrophysiological measurement, the model could be parameterized to yield an effective tool for future investigation of tailored ablation strategies and their effects on atrial fibrillation. [ABSTRACT FROM AUTHOR]

Voltage fluctuations and interharmonics have an inherent relationship. The magnitude of voltage waveform can fluctuate if it contains interharmonics. Although the impact of voltage fluctuation caused by a single interharmonic has been understood due to recent research activities, little knowledge is available on the impact of a pair of interharmonics. In reality interharmonics often appear in pairs. The objective of this paper is to investigate voltage fluctuations caused by a pair of interharmonics. Using rms and peak values as indices, the amount of voltage fluctuations caused by a pair of interharmonics is determined. Analytical formulas to estimate the impact are developed. One of the interesting findings of this work is that the voltage fluctuation impact of a pair of interharmonics can be equivalenced into that produced by one interharmonic component. This paper also presents potential applications of the findings. [ABSTRACT FROM AUTHOR]

The paper presents the small-signal stability analysis of ac/dc system with a novel discrete-time HVDC converter model based on multirate sampling. The complete ac/dc system model has been developed in state space framework in modular fashion along with suitable interface of various subsystems involved. The model development is proposed in generalized framework and any degree of detail can be easily included. The sample case study has been carried out for the ac network in which an HVDC link is embedded. The studies reported in this paper are very much confirmatory as the model-based control design is concerned and the same has been validated through detailed nonlinear digital simulation. The model can be effectively utilized for stability study of two terminal systems. [ABSTRACT FROM AUTHOR]

Software energy estimation is a critical step in the design of energy-efficient embedded systems. Instruction-level simulation techniques, despite several advances, remain too slow for iterative use in system-level exploration and for embedded systems with high software complexity. In this paper, we propose a methodology called hybrid simulation, which combines instruction set simulation with selective native execution (execution of some parts of the program directly on the simulation host computer). Hybrid simulation attempts to overcome the disadvantages of instruction-level simulation (low speed) and pure native execution (estimation accuracy and inapplicability to target-dependent code) while exploiting their advantages. In order to perform the energy estimation for natively executed subprograms, hybrid simulation leverages previously developed techniques for software energy macromodeling. This paper identifies and addresses the main challenges involved in hybrid simulation, including control/data transfer and memory synchronization between instruction set simulation and native execution domains, estimation errors due to macromodeling, and simulation overheads for switching between domains. We present an automatic tool flow for hybrid simulation, which analyzes a given program and selects functions for native execution in order to achieve maximum estimation efficiency while limiting estimation error. Our tool generates native ‘drop-in’ modules that are linked into the instruction set simulator (ISS) and simulation ‘stubs’ that are linked with the application to facilitate hybrid simulation. We have applied the proposed hybrid simulation methodology to a variety of embedded software programs, resulting in average speedups of 25.2× (maximum of 124×) and estimation error of only 3% (maximum of 6%), as compared to one of the fastest publicly available ISSs. [ABSTRACT FROM AUTHOR]

This paper presents a new technique for online identification of an induction motor rotor time constant. The technique is designed for a shaft-sensorless indirect field-oriented control induction motor drive with a model reference adaptive system (MRAS)-based speed estimator. The MRAS estimator is sensitive to the changes in the rotor time constant, and online identification of that parameter is essential. If rotor parameter error exists, it does not only change the achieved rotor speed, but it also changes the dynamic behavior of the whole field control and speed estimation structure. The proposed rotor parameter update is exactly based on the newly introduced dynamic model of the potentially detuned MRAS-based speed estimator. The technique avoids the use of test signals and rather extracts the needed information from the ever-present signal jitter, which is inherent to the current and speed servo loops. This paper demonstrates that the phase angle difference between some spectral components of selected small signals within the speed estimator can be used for rotor parameter update. Computer simulations and experiments are performed under a variety of conditions to validate the effectiveness of the proposed rotor parameter update technique. [ABSTRACT FROM AUTHOR]