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It is often appealing to assume that existing solutions can be directly applied to emerging engineering domains. Unfortunately, careful investigation of the unique challenges presented by new domains exposes its idiosyncrasies, thus often requiring new approaches and solutions. In this paper, we argue that the “smart” grid, replacing its incredibly successful and reliable predecessor, poses a series of new security challenges, among others, that require novel approaches to the field of cyber security. We will call this new field cyber–physical security. The tight coupling between information and communication technologies and physical systems introduces new security concerns, requiring a rethinking of the commonly used objectives and methods. Existing security approaches are either inapplicable, not viable, insufficiently scalable, incompatible, or simply inadequate to address the challenges posed by highly complex environments such as the smart grid. A concerted effort by the entire industry, the research community, and the policy makers is required to achieve the vision of a secure smart grid infrastructure. [ABSTRACT FROM PUBLISHER]

“Multisourcing” has emerged as an important strategy for global information technology (IT) service outsourcing in today's turbulent business environment. The existing literature on IT service provides only limited insights into this phenomenon. However, in the manufacturing domain, a similar concept, supply base management, has been extensively studied. In this paper, we integrate related research in IT service and manufacturing to explore how firms can successfully pursue global multisourcing strategy in IT service. Specifically, we first conceptualize a firm's multisourcing supply base along the dimensions of breadth and depth and theorize about the impact of these two dimensions on outsourcing outcomes. Second, based on this framework, we analyze four configurations of multisourcing supply base. Finally, we conduct case studies of two global financial services firms to illustrate the configurations and identify patterns of evolution of global multisourcing strategy in customized information systems development. [ABSTRACT FROM PUBLISHER]

In this paper, we review recent developments in the field of outsourcing and offshoring and the implications for engineering management. We examine three aspects involved in outsourcing and offshoring, namely, sourcing models, coordination, and value extracted from outsourcing projects. We conclude that additional research is needed on recent trends in outsourcing and the impact of such change process on the practice of engineering management. [ABSTRACT FROM PUBLISHER]

The globalization of complex engineering services has resulted in physically dispersed teams that can no longer rely on the traditional and familiar oral transmission of engineering expertise nor can they assume knowledge of their team members’ culture. Yet, such teams need to be able coordinate effectively the dispersed knowledge of team members. We know little about how cultural differences among engineering team members impact the coordination of dispersed knowledge, so called transactive memory systems (TMSs)—or “who knows what” and “who knows who knows what.” In this paper, we present a longitudinal case study of a dispersed, cross-cultural team involving U.S. and Romanian engineers. The cultural differences in values, practices, and institutions had a major impact on TMS indicators of specialization, coordination, and credibility. The paper demonstrates how the cultural differences impeded TMS development. The results provide insight into TMS as an implicit coordination mechanism in a global team. We provide advice in terms of interventions that can promote the development of TMS in a culturally diverse team. [ABSTRACT FROM PUBLISHER]

This paper describes the structure and the underlying rationale of a new course dedicated to capability maturity model integration (CMMI)-directed design of wireless sensor networks (WSNs)-based biomedical applications that stresses: 1) engineering-, medico-engineering-, and informatics-related issues; 2) design for general- and special-purpose systems; and 3) the creation of synergistic effects that enable formation of entrepreneurial multidisciplinary teams able to organize and implement the development of these health-related pervasive computing applications. Formal education so far still focuses on treating only strictly separated and specialized topic areas. However, as the need for cooperation and mutual learning between students oriented toward different fields grows, the need for a multidisciplinary educational approach becomes more and more important. For a technical education to be complete, it is no longer enough to train scientists and engineers solely in technical areas. In development and implementation of technology-driven applications, multidisciplinary issues should be properly addressed in the academic sense. The interdisciplinary understanding and synergy achieved are tested through examinations and workshops. The transdisciplinary knowledge improvement is also statistically evaluated, using a system of metrics developed experimentally. [ABSTRACT FROM AUTHOR]

Effective engineering-change management (ECM) is a real challenge in mechanical engineering industry and manufacturing companies. Computer-aided design systems are usually connected to other systems such as ERP or product data management, but currently this integration does not provide effective means to manage engineering change (EC). While communication between multidisciplinary teams working on a project is known to have a significantly positive impact on the ECM, the communication between disciplines is generally performed solely through message exchange. Experts could feel the need to meet to agree on the requested changes, which in turn translates into longer design and manufacturing processes. There is a need for a system that assists human experts in making decisions about ECs. Such a system will considerably reduce the processing time following a change-request procedure. This paper proposes a collaborative tool named EchoMag, which assists designers and experts during the change-management process. The proposed system ensures the coherence of data between the various disciplines involved in the change process. EchoMag also assists experts in making decisions by proposing alternative solutions when change requests are not agreed upon. Software agents were used to implement EchoMag for which a prototype was developed. Results of the implementation are discussed. [ABSTRACT FROM PUBLISHER]

Forecasting the diffusion of innovations plays a major role in managing technology development and in engineering management overall. In this paper, we extend the conventional Bass model stochastically by specifying the error process of sales as log-normal and mean-reverting. Our model satisfies the following reasonable properties, which are generally ignored in the existing literature: sales cannot be negative, the error process can have a memory, and sales fluctuate more when they are high and less when they are low. The conventional and widely used model that assumes normally distributed error term does not have these properties. We address how to forecast properly under the log-normal and mean-reverting error process, and show analytically and numerically that in our extended model sales forecasts can substantially alter conventional Bass forecasts. We also analyze the model empirically, showing that our extension can improve the accuracy of future sales forecasts. [ABSTRACT FROM PUBLISHER]

Fit represents a central concept for organizational design, but extant research maintains a static focus on fit, a focus that is incommensurate with the fundamentally dynamic nature of organizations and their environments. Most key organizational environments are inherently dynamic; hence, the corresponding organizational designs required for fit are necessarily dynamic too. The problem is, the dynamics of fit are not addressed well by extant theory in organization and management sciences. Alternatively, organizations can be viewed as systems of purposeful design, and designing organizations to maintain fit and respond to dynamic environments over time may be informed well by theory and practice in engineering fields where such design is well established. In this paper, we abstract to the level of airplane design, and we utilize the dynamical language and integrated system of concepts, definitions, and interrelationships from the engineering field Aerodynamics to extend organization and management sciences and address the problem of organizational design in a dynamic context. We begin with a focused summary of the literature regarding the nature of organizational fitness. We then outline a conceptual model adapted to organizational design from Aerodynamics, and we summarize the key aerodynamics concepts stability and maneuverability to inform our conceptualization in terms of both airplane and organization design. This paper enables us to articulate a set of propositions and measures that form a basis for empirical testing. This paper also reveals important, dynamic organizational design tradeoffs and implications, and it shows how such conceptualization can elucidate new insights via comparison with and extension to extant theory. [ABSTRACT FROM PUBLISHER]

The article discusses various reports published within the issue, including articles on microelectromechanical systems, presented at the CWMEMS '05 workshop, and other articles written oby students presented at the IEEE Canadian Conference on Electrical and Computer Engineering.

This paper proposes a boundary analysis method for reliability and economic assessment in distribution systems. The main purpose is to deal with uncertainties of input data, especially when statistical information is unavailable or insufficient. The presented method uses interval numbers to enclose variability and incertitude in reliability and economic parameters, and provides the estimates on upper and lower bounds of reliability and economic indices. The proposed method has been applied to real-life distribution reinforcement projects. Case studies demonstrated effectiveness and efficiency of the method. [ABSTRACT FROM AUTHOR]

This paper presents both analytical models and Monte Carlo simulations concerning strain engineering in n-type silicon FinFETs. Our analysis identifies the stress configurations and the physical mechanisms able to produce a significant stress-induced mobility enhancement and provides the insight necessary for device optimization. We first derive analytical expressions for the stress-induced changes of the subband minima and of the transport masses, which clearly identify the stress components leading to mobility improvements. Then, we present multisubband Monte Carlo mobility simulations, which confirm the potentials for remarkable stress-induced mobility enhancements in n-FinFETs. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to evaluate the impact of process-induced stress on the generation current of fully strained Si1-x Gex source/drain junctions. The Ge content of the compressively strained SiGe epitaxial layer plays a key role the tensile stress levels present in the underlying Si substrate. Current-voltage (I-V) measurements were employed to further investigate the leakage current enhancement due to the stress-induced bandgap narrowing in the Si depletion region, when extended defects are formed. An empirical approach is proposed to describe the Ge content dependence of the bandgap-shrinkage-induced leakage current. An increase of the intrinsic carrier concentration as a function of the stress mismatch is observed. Moreover, the role of the epilayer thickness in the generation current is also discussed. [ABSTRACT FROM AUTHOR]

This paper presents an equivalent-circuit model of an asymmetric disc-type ultrasonic motor and discusses its applications in the evaluation of the motor's characteristics. The modeling process is based on the mechanical vibrations of the piezoelectric ceramic disk in both the radial (tangential) and coupling directions, the rigid body assumption of the rotor, and the assumption of a single contact point between the stator and the rotor with the most significant lateral elliptic motion effect. The overall model is composed of three admittance-type equivalent circuit models of the metal back plate, the stator, and the rotor. The advantages of the model are exemplified by comparing the numerical and experimental results, thereby showing that the model may be useful and pragmatic for electrical engineers in designing, simulating, and characterizing such motors. [ABSTRACT FROM AUTHOR]

This paper describes how to calibrate a four- terminal-pair (4TP) LCR meter at the right (90°) angle. The LCR meter uses the right angle signal to process a synchronous detector as a vector signal receiver. The right-angle calibration method uses, at a minimum, one variable-phase signal generator (SG) and a phase shift circuit. The SG does not require a precision right angle, but it does need good phase stability. The described phase shifter provides the required differential phase of nearly the right angle. As a result, the right-angle phase deviation of the LCR meter is better than 65 μrad (0.223′) with 37-μrad (0.127′) uncertainty at 10 MHz. This method is also applicable to the phase calibration of a vector network analyzer. [ABSTRACT FROM AUTHOR]

In power distribution networks the load varies within any given time frame. It may, therefore, seem that a good approach to reduce losses would be the solving of a network reconfiguration problem to suit each of the significant load variations. However, frequent changes in configuration can trigger outages or cause transient problems; they are best avoided. A recent formulation of this problem explicitly considers load variations and proposes to restrain frequent reconfigurations by assuming that network topologies will remain unchanged for a given planning period. This formulation leads to a much larger optimization problem than that traditionally used for network reconfiguration; moreover, it requires a new approach to optimization which is capable of dealing with energy flows instead of only instantaneous power flows. Such an approach is proposed in this paper, which discusses the design of an adaptive hybrid genetic algorithm that fulfills these new requirements. Key concepts in evolutionary computation and analysis of distribution systems are explored to develop this new algorithm. Application to real case studies certifies its benefits. [ABSTRACT FROM AUTHOR]

Deregulation of the electric power industry has introduced new uncertainties for market participants and made planning of transmission expansion more difficult. More flexible transmission expansion plans are needed, to cope with the increased risks. In this paper, a novel planning approach is proposed to meet the above challenge. In our approach, the planning process is modeled as a mixed integer nonlinear programming (MINLP) problem, so that conflicting objectives can be optimized simultaneously. To minimize planning risks, our method identifies several scenarios based on statistics and expert knowledge; the most flexible expansion plan is selected as the plan that has least adaptation cost. The proposed method is tested with the IEEE 14-bus system. Promising results are obtained to demonstrate the effectiveness of our method. [ABSTRACT FROM AUTHOR]

The objective of this paper is to present a new fuzzy logic method for midterm energy forecasting. The proposed method properly transforms the input variables to differences or relative differences, in order to predict energy values not included in the training set and to use a minimal number of patterns. The input variables, the number of the triangular membership functions and their base widths are simultaneously selected by an optimization process. The standard deviation is calculated analytically by mathematical expressions based on the membership functions. Results from an extensive application of the method to the Greek power system and for different categories of customers are compared to those obtained from the application of standard regression methods and artificial neural networks (ANN). [ABSTRACT FROM AUTHOR]

This paper describes use of a multiobjective optimization method, elitist nondominated sorting genetic algorithm version II (NSGA-II), to the generation expansion planning (GEP) problem. The proposed model provides for decision maker choice from among the different trade-off solutions. Two different problem formulations are considered. In one formulation, the first objective is to minimize cost; the second objective is to minimize sum of normalized constraint violations. In the other formulation, the first objective is to minimize investment cost; the second objective is to minimize outage cost (or maximize reliability). Virtual mapping procedure is introduced to improve the performance of NSGA-II. The GEP problem considered is a test system for a six-year planning horizon having five types of candidate units. The results are compared and validated. [ABSTRACT FROM AUTHOR]

Wind-diesel systems represent a proactive step towards sustainable remote communities. However, for high ratios of wind energy, the necessity of a dump load and the diesel operating constraints need to be considered. Energy storage systems offer a means of optimizing energy use and further reducing consumption of diesel fuel. This paper proposes a methodology for storage sizing based on stochastic optimization. The problem is formulated and solved using representative data. The dependence of storage sizing and the cost of delivered energy on wind penetration levels, storage efficiency, and diesel operating strategies are considered. Results demonstrate that for high wind penetration, the availability of storage, together with an appropriate diesel operating approach, can result in significant cost savings in terms of fuel and operating costs. [ABSTRACT FROM AUTHOR]

In this paper, a primary frequency control strategy based on fuzzy logic, designed for variable-speed wind generators, is proposed and tested on a 2.2-kW test bench. The fuzzy logic supervisor ensures a regular primary reserve for a large range of wind speeds without any wind speed measurement. This supervisor controls simultaneously the generator torque and the pitch angle to keep the primary reserve; it determines in real time the generator power reference value. The fuzzy logic supervisor is compared to a simpler strategy, based only on the control of the generator torque. This classical strategy ensures a regular power reserve only when the wind generator operates at full load, and the generator power reference needs to be determined previously or by the network manager. A procedure for implementing a fuzzy logic supervisor in real time is proposed. The experiments indicate the regularity of the power reserve and the ability to contribute to frequency control. [ABSTRACT FROM AUTHOR]

This paper presents a new approach for finding the sequence of events that may lead to catastrophic failure in a power system. The probable sequences (of events) leading to catastrophic failures are identified using risk indices which incorporate the severity as well as the probability of the contingencies. Probable collapse sequences are identified offline for different possible loading conditions using a modified fast decoupled load flow method which considers the voltage and frequency dependence of loads and generator regulation characteristics and stored in a knowledge base. Pattern recognition method and fuzzy estimation are used for online identification of collapse sequences for any operating condition from the stored database (knowledge base). [ABSTRACT FROM AUTHOR]

This paper proposes a new control approach for a unified power flow controller (UPFC) for power system oscillation damping. This control is simple to implement, yet is valid over a wide range of operating conditions. It is also effective in the presence of multiple modes of oscillation. The proposed control is implemented in several test systems and is compared against a traditional PI control. [ABSTRACT FROM AUTHOR]

In this paper, dead band control algorithms using a performance index of the load tap changing (LTC) tap position are proposed to reduce the tap changing operation times. The performance index is defined as the customer voltage quality with the tap position of LTC transformer. In addition, dead band control algorithms using the load diversity values of the feeders are proposed. The mathematical formulations of the proposed dead band control algorithms are introduced. A sample case study is shown to verify the effectiveness of the proposed dead band control algorithms. [ABSTRACT FROM AUTHOR]

In order that the supply of electric power remain stable and sustainable, a certain level of power quality must be maintained while securing energy resources and resolving environmental issues. The distributed generation (DG) has become an essential and indispensable element of such distribution systems from both an environmental and an energy security perspective. However, the installation of DGs in distribution systems may cause variations of voltage on distribution feeder because the DG power outputs may change randomly and dramatically. Generally, the sending voltage at substation in distribution systems can be regulated by an under load tap changer (ULTC) designed to maintain customers' receiving voltages within a predetermined range. Voltage regulation performed by ULTC calls for two parameters: the equivalent impedance and the load center voltage. Therefore, in distribution networks with DG interconnections, these parameters should be designed with attention not only to load variations but also to DG outputs. This paper proposes a method for designing ULTC parameters with reference to variations in DG output. The proposed algorithm is tested with IEEE 13-node system and Korean model network. The results demonstrate the validity of the proposed design method for varying DG distribution. [ABSTRACT FROM AUTHOR]

In a competitive electricity market, price forecasts are important for market participants. However, electricity price is a complex signal due to its nonlinearity, nonstationarity, and time variant behavior. In spite of much research in this area, more accurate and robust price forecast methods are still required. In this paper, a combination of a feature selection technique and cascaded neuro-evolutionary algorithm (CNEA) is proposed for this purpose. The feature selection method is an improved version of the mutual information (MI) technique. The CNEA is composed of cascaded forecasters where each forecaster consists of a neural network (NN) and an evolutionary algorithm (EA). An iterative search procedure is also incorporated in our solution strategy to fine-tune the adjustable parameters of both the MI technique and CNEA. The price forecast accuracy of the proposed method is evaluated by means of real data from the Pennsylvania-New Jersey-Maryland (PJM) and Spanish electricity markets. The method is also compared with some of the most recent price forecast techniques. [ABSTRACT FROM AUTHOR]

As power systems becoming more closely interconnected and are being deregulated in energy markets, distributed simulations among different dispatch centers are highly required for online full system analysis and control applications. In this paper a new algorithm for distributed transient stability simulation of interconnected power systems is presented. Based on a Jacobian-free Newton-GMRES(m) method, this algorithm requires only exchanges of states of boundary buses among different regions. Therefore, it has strong scalability in distributed computing environments built on heterogeneous computing resources. Moreover, several accelerating methods are developed to enhance its efficiency, including continuous preconditioning with adaptive preconditioners, predicting boundary conditions and multistep coordination. The standard IEEE 39-bus system and a real power system with 1165 buses were used as test systems. The test results show that these accelerating methods greatly enhance the convergence rate of the proposed algorithm and reduce communication costs remarkably, which proves the novel algorithm is feasible and can be adopted in wide area networks with high-latency. [ABSTRACT FROM AUTHOR]

The paper proposes a systematic scheme for building compact and transparent fuzzy rule-based classifiers for rapid stability assessment; the classifiers are initialized by large accurate decision trees (DTs). The approach starts by selecting strategic monitoring buses where phasor measurement units (PMUs) are placed to capture wide-area response signals in real-time operation. These measurements are processed in the time and frequency domains for extracting selected decision features such as the peak spectral density of the angle, frequency and their dot product evaluated over the grid areas. These so-called wide-area severity indices (WASI) are reliable time-varying stability indicators that form the basis of an effective classification system. Large-size DTs are used to generate initial accurate classification boundaries for decision making as early as 1 s or 2 s after fault clearing. From the DT classification boundaries, fuzzy membership functions (MFs) are developed and the corresponding fuzzy rule base is formulated parsimoniously by eliminating redundant MFs and rules using a similarity measure. The resulting fuzzy-rule classifiers are successfully tested for systemwise and area-wise contingencies based on a large database of detailed simulations of the Hydro-Quebec grid and are further confirmed on actual measurements recorded with existing wide-area measurements (WAMS). [ABSTRACT FROM AUTHOR]

Electromagnetic transient program (EMTP) simulators are being widely used in power system dynamics studies. However, their capability in real-time simulation of power systems is compromised due to the small time step used and relatively slow simulation speed. The shifted frequency analysis (SFA) is then proposed to accelerate the EMTP simulations for power system dynamics. The objective of this paper is to extend the SFA method [7] to model the induction machines in EMTP. By analyzing the relationship between rotor and stator physical variables, a phase-coordinate model with lower number of equations is first derived. Based on this, an SFA model is proposed as a general purpose model capable of simulating both fast transients and slow dynamics. Case study results have confirmed the SFA induction machine model is a valuable component for real-time EMTP simulations. It is observed that the SFA model is in excess of 70 times faster than the standard EMTP model when simulating dynamics with frequency spectra close to the fundamental power frequency. [ABSTRACT FROM AUTHOR]

This paper describes a methodology to identify potential conflicts among power flow control devices that may slow down or impair convergence. The proposed methodology is based on the eigenvalue analysis of the sparse Jacobian matrix associated with the Newton power flow with controls. Practically identical results are obtained from a smaller control sensitivity matrix. The implementation in a power flow program has been tested using both small- and large-scale systems. The results presented validate and clearly indicate the effectiveness of the proposed technique. [ABSTRACT FROM AUTHOR]

Many applications in modern distribution management systems (DMS) need the support of robust and reliable radial power flow analysis. In this connection, although radial power flow solution algorithms are widely proposed in the literature, their application is often complicated by the presence of uncertainties affecting the distribution network operation. The effect of these uncertainties could affect the power flow solution to a considerable extent. A comprehensive tolerance analysis is therefore required in order to incorporate the effect of data uncertainties into power flow analysis. To address this problem, in this paper the employment of interval constraint propagation (ICP) is proposed. ICP is an effective technique for refining enclosures to solutions of nonlinear systems of equations by merging interval mathematic and constraint propagation techniques. Several numerical results are presented and discussed in order to assess the effectiveness of the proposed methodology as an alternative to sampling-based technique, in radial power flow analysis. [ABSTRACT FROM AUTHOR]

The paper addresses the problem of predicting hourly load demand using adaptive artificial neural networks (ANNs). A particle swarm optimization (PSO) algorithm is employed to adjust the network's weights in the training phase of the ANNs. The advantage of using a PSO algorithm over other conventional training algorithms such as the back-propagation (BP) is that potential solutions will be flown through the problem hyperspace with accelerated movement towards the best solution. Thus the training phase should result in obtaining the weights configuration associated with the minimum output error. Data are wavelet transformed during the preprocessing stage and then inserted into the neural network to extract redundant information from the load curve. This results in better load characterization which creates a more reliable forecasting model. The transformed data of historical load and weather information were trained and tested over various periods of time. The generalized error estimation is done by using the reverse part of the data as a "test" set. The results were compared with traditional BP algorithm and offered a high forecasting precision. [ABSTRACT FROM AUTHOR]

Room acoustics is an important but difficult part of room design. Good design is achieved more on the basis of acoustic expertise than on pure engineering design. Among the reasons for this situation are the limitations due to acoustic measurement system design and the difficulties in solving inverse acoustic room problems given acoustic requirements. This paper investigates the means for improving the room acoustic measurement system and for validating simulation approaches for room acoustics design. [ABSTRACT FROM AUTHOR]

International standard bodies have specified an instrument capable of detecting and assessing the severity of lighting flicker, which is called a flickermeter. However, a deficiency with regard to flicker caused by high-frequency interharmonics has been reported in the recent literature. In this paper, another deficiency of the International Electrotechnical Commission (IEC) flickermeter with regard to low-frequency interharmonics, whose frequencies are below the difference between the fundamental frequency and the cutoff frequency of a bandpass filter of the IEC standard flickermeter, will be discussed and illustrated based on analysis and numerical experiments. A new approach based on down-up sampling in the discrete-time sample domain is also proposed to address the flicker-detection problem associated with interharmonics. We demonstrate the efficacy of the proposed method by a comparison with the current flickermeter standard in the presence of interharmonics. [ABSTRACT FROM AUTHOR]

This article reports that several changes in the periodical "IEEE Transactions on Software Engineering," published as of February 01, 2004, will make the processing of articles more timely and more effective. First, the length restriction on submitted manuscripts has been removed. This should allow authors to document results in appropriate length papers. Despite the change, authors are encouraged to keep papers as short as possible. Second, Transactions on Software Engineering manuscript management has been moved to the Web-based Manuscript Central system. This system makes all aspects of manuscript processing much more efficient and it allows everybody involved in processing papers, including authors, to obtain details of the state of manuscripts as they are processed. Third, preprints in the future will be available online two months before the issue cover date. Software remains a critical industry to the world. The impact of software is tremendous, both when it works and when it doesn't.

The article announces awards given to educators of electrical engineering including the 2008 Chen-To Tai Distinguished Educator Award to Weng Cho Chew, the 2008 John Kraus Antenna Award to Daniel H. Schaubert, and the 2008 R. W. P. King Award to Ashwin K. Iyer.

Understanding the business (interaction) protocol supported by a service is very important for both clients and service providers: It allows developers to know how to write clients that interact with a service, and it allows development tools and runtime middleware to deliver functionalities that simplifies the service development life cycle. It also greatly facilitates the monitoring, visualization, and aggregation of interaction data. This paper presents an approach for discovering protocol models from real-world service interaction logs. It presents a novel discovery algorithm, which is widely applicable, robust to different kinds of imperfections often present in real-world service logs, and able to derive protocols of small sizes targeted for human understanding. As interring the most precise and concise model is not always possible from imperfect service logs using purely automated method, the paper presents a novel method for user-driven refinement of the discovered protocol models. The proposed approach has been implemented and experimental results show its viability on both synthetic and real-world data sets. [ABSTRACT FROM AUTHOR]

The flatness measurement of a large 2-D flat work- piece such as a satellite solar panel substrate is a key problem in its manufacturing process. Based on the current measuring methods and the actual engineering project, a new noncontact high-precision, low-cost large 2-D flat workpiece flatness measuring system is developed, in which the techniques of oblique optical triangle measuring structure, virtual measurement datum plane, and error self-correction are adopted. By means of the oblique optical triangle measuring structure that is first proposed, the measuring area and resolution of the measuring system can be greatly increased. Meanwhile, on the basis of the techniques of virtual measurement datum plane and error self-correction, the noncontact high-precision, low-cost flatness measurement can be realized on a nonprecise large metallic platform. Experimental results on the satellite solar panel substrate indicate the correctness and effectiveness of the proposed noncontact flatness-measuring system of the large 2-D flat workpiece. Although the specific application of the satellite solar panel substrate is presented in this paper, the proposed measurement techniques and measuring system could be applied independent of the nature or use of the large 2-D flat workpieces. [ABSTRACT FROM AUTHOR]

This paper presents a new concept of removing impulse noise through primary implicant elimination (PIE) applied to a logical system representation of the data. Applicable to binary and grayscale images, errors are corrected efficiently, in terms of the number of computations and memory requirements, while the fine details of the image are mostly preserved. Three filtering algorithms are presented: a general form in addition to iterative and switching variations. Experimental results on salt-and-pepper impulse noise, as well as on random-valued impulse noise, are compared against the performance of traditional median-based filters (both regular and switching) and are shown to be most successful in the often difficult case of when the original image contains many detailed patterns. [ABSTRACT FROM AUTHOR]

Porous media modeling is relevant in several applications, such as agricultural engineering, where soil compaction analysis requires the estimation of soil transport properties. For example, the prediction of root growing patterns and their environmental impact is usually measured by analyzing soil fluid infiltration capacity and water retention. Recently, tomographic images have been used in nondestructive tests of soil. However, using such images is challenging for two reasons: 1) Tomographic images are usually noisy, which complicates their segmentation, and 2) modeling the soil structure requires establishing adjacency relations among neighboring tomographic slices, which has a significant computational cost due to the combinatorial nature of this problem. In this paper, we propose a solution for both problems. The experimental results show that soil samples can be analyzed and classified with significant accuracy using our proposed approach. [ABSTRACT FROM AUTHOR]

Engineering return stroke models can be categorized either as current generation (traveling current source type) models or current propagation (transmission line type) models. The current generation models are described among other parameters by a corona current distributed along the channel. Recent studies show that there is equivalence between the models of current generation and current propagation types. Due to this equivalence, any engineering return stroke model of current propagation type can be described in terms of an equivalent corona current per unit channel length. The measurements conducted within 10-500 m from triggered lightning flashes show that the electric field of subsequent return strokes at these distances flattens within 15 µs or so. In this paper, the constraints imposed by this feature on the temporal and spatial variation of the equivalent corona current are investigated. The results show that in order for the close fields to flatten within 15 µs or so, the equivalent corona current, should be bipolar and the corona current wave shape at late times should be identical to that of the longitudinal current time derivative. This is in contrast to most of the engineering models of current generation type, in which the corona current is assumed to be unipolar [ABSTRACT FROM AUTHOR]

Tests of up to three simultaneously firing 40-cm NASA's Evolutionary Xenon Thrusters took place at NASA Glenn Research Center. In addition to numerous engineering tests, the experiment was instrumented to measure plasma properties in the interacting plumes, charge exchange return current to the active and dormant thrusters, and current and plasma properties at various locations. This paper describes the use of Nascap-2k to calculate plume potentials and charge exchange ion return currents to active and dormant ion optics and to diagnostic probes. Calculations were performed varying the numbers of active thrusters, thruster power levels, and gimbaling. The results were extrapolated to space conditions. Despite several simplifying assumptions, we obtained good agreement with experimental results. No major problems associated with multiple thruster operation were found. [ABSTRACT FROM AUTHOR]

Industrial control engineers continue to make extensive use of ladder logic for programming programmable logic controllers (PLCs) although the limitations of the language are well recognized. Evaluations of alternative approaches have been conducted in academia but industrial users have shown little enthusiasm for the recommendations. This work addresses this by conducting an experimental evaluation using a range, of skilled and unskilled participants to establish which of four software design methodologies is best suited to the support of flexible manufacture in a small program through an experiment in which "right first time" rates and completion time are measured. Unlike earlier work which had an emphasis on program creation, this paper reports on process modification. The object modelling tool tested, Enterprise Controls, was found to be the most effective methodology under study with the highest "right first time" rate as well as demonstrating a 80% time saving over traditional relay ladder logic. This was closely matched by step-based ladder logic, provided the concept is used correctly. Areas for further work include the assessment of program development time during setup and control performance in use. [ABSTRACT FROM AUTHOR]

In this paper, we propose an intelligent stationary system of uninterrupted noncontact temperature measurement and detection of overheated bearings in trains. The proposed mea- surement system is a stand-alone class, based on remote infrared (IR) measurement and recognition of the hot lid of axle bearing. The measurement system is useful for continuous maintenance without traffic interruption. It consists of three parts: 1) the measurement device; 2) the alert device; and 3) a PC with a virtual instrument and appropriate database. The measurement device is based on an IR detector installed on both railway sides on the same axis as the wheel axle. The whole system is installed at three locations, which are located 500 m apart. The communication among system parts is done using RS-232/485 interfaces and radio modems. This system has a vital role in safe railroad operations, preventive maintenance, and damage avOidance of axle wheel bearings in railways. [ABSTRACT FROM AUTHOR]

This paper investigates issues related to practical implementation of the one-quarter of cycle-based estimation method [here called delayed signal cancellation (DSC)] for online detection of positive and negative sequence components of three-phase quantities. The detection error due to non-ideal sampling frequency is calculated. Furthermore, the effect of the DSC method on estimation when harmonic components are present in the input signal is analyzed. It is shown how harmonics transfer through the DSC and how a non-ideal sampling frequency affects the estimation of the harmonics. Experimental verification of the analytical results is presented. [ABSTRACT FROM AUTHOR]

Quantum-dot Cellular Automata (QCA) has been widely advocated as a new device architecture for nanotechnology. QCA systems require extremely low power, together with the potential for high density and regularity. These features make QCA an attractive technology for manufacturing memories in which the paradigm of memory-in-motion can be fully exploited. This paper proposes a novel serial memory architecture for QCA implementation. This architecture is based on utilizing new building blocks (referred to as tiles) in the storage and input/output circuitry of the memory. The QCA paradigm of memory-in- motion is accomplished using a novel arrangement in the storage loop and timing/clocking; a three-zone memory tile is proposed by which information is moved across a concatenation of tiles by utilizing a two-level clocking mechanism. Clocking zones are shared between memory cells and the length of the QCA line of a clocking zone is independent of the word size. QCA circuits for address decoding and input/output for simplification of the Read/Write operations are discussed in detail. An extensive comparison of the proposed architecture and previous QCA serial memories is pursued in terms of latency, timing, clocking requirements, and hardware complexity. [ABSTRACT FROM AUTHOR]

In the last decade, distributed generation, with its various technologies, has increased its presence in the energy mix presenting distribution networks with challenges in terms of evaluating the technical impacts that require a wide range of network operational effects to be qualified and quantified. The inherent time-varying behavior of demand and distributed generation (particularly when renewable sources are used), need to be taken into account since considering critical scenarios of loading and generation may mask the impacts. One means of dealing with such complexity is through the use of indices that indicate the benefit or otherwise of connections at a given location and for a given horizon. This paper presents a multiobjective performance index for distribution networks with time-varying distributed generation which consider a number of technical issues. The approach has been applied to a medium voltage distribution network considering hourly demand and wind speeds. Results show that this proposal has a better response to the natural behavior of loads and generation than solely considering a single operation scenario. [ABSTRACT FROM AUTHOR]

This paper investigates voltage and reactive power control in distribution systems and how the presence of synchronous machine-based distributed generation (DG) affects the control. A proper coordination among the onload tap changer (OLTC), substation switched capacitors and feeder-switched capacitors in order to obtain optimum voltage and reactive power control is proposed. It is assumed that there is no communication link between the OLTC and the capacitors, a normal case in distribution system operation these days. The results indicate that the proposed method decreases the number of OLTC operations, losses, and voltage fluctuations in distribution systems, with and without DG present. The power-flow reversal due to the lJG is shown not to interfere with the effectiveness of the OLTC operation. Further, it is also shown that as long as the available capacitors are enough to compensate the reactive power demand, the DG operation mode does not give a significant effect to the distribution system losses. However, DG operating at a constant voltage is beneficial for a significant reduction of OLTC operation and voltage fluctuation in the distribution system. [ABSTRACT FROM AUTHOR]

Increased realism in software engineering experiments is often promoted as an important means of increasing generalizability and industrial relevance. In this context, artificiality, e.g., the use of constructed tasks in place of realistic tasks, is seen as a threat. In this paper, we examine the opposite view that deliberately introduced artificial design elements may increase knowledge gain and enhance both generalizability and relevance. In the first part of this paper, we identify and evaluate arguments and examples in favor of and against deliberately introducing artificiality into software engineering experiments. We find that there are good arguments in favor of deliberately introducing artificial design elements to 1) isolate basic mechanisms, 2) establish the existence of phenomena, 3) enable generalization from particularly unfavorable to more favorable conditions (persistence of phenomena), and 4) relate experiments to theory. In the second part of this paper, we summarize a content analysis of articles that report software engineering experiments published over a 10-year period from 1993 to 2002. The analysis reveals a striving for realism and external validity, but little awareness of for what and when various degrees of artificiality and realism are appropriate. Furthermore, much of the focus on realism seems to be based on a narrow understanding of the nature of generalization. We conclude that an increased awareness and deliberation as to when and for what purposes both artificial and realistic design elements are applied is valuable for better knowledge gain and quality in empirical software engineering experiments. We also conclude that time spent on studies that have obvious threats to validity that are due to artificiality might be better spent on studies that investigate research questions for which artificiality is a strength rather than a weakness. However, arguments in favor of artificial design elements should not be used to justify studies that are badly designed or that have research questions of low relevance. [ABSTRACT FROM AUTHOR]

The investment in an automated fabric defect detection system is more than economical when reduction in labor cost and associated benefits are considered. The development of a fully automated web inspection system requires robust and efficient fabric defect detection algorithms. The inspection of real fabric defects is particularly challenging due to the large number of fabric defect classes, which are characterized by their vagueness and ambiguity. Numerous techniques have been developed to detect fabric defects and the purpose of this paper is to categorize and/or describe these algorithms. This paper attempts to present the first survey on fabric defect detection techniques presented in about 160 references. Categorization of fabric defect detection techniques is useful in evaluating the qualities of identified features. The characterization of real fabric surfaces using their structure and primitive set has not yet been successful. Therefore, on the basis of the nature of features from the fabric surfaces, the pro- posed approaches have been characterized into three categories; statistical, spectral and model-based. In order to evaluate the state-of-the-art, the limitations of several promising techniques are identified and performances are analyzed in the context of their demonstrated results and intended application. The conclusions from this paper also suggest that the combination of statistical, spectral and model-based approaches can give better results than any single approach, and is suggested for further research. [ABSTRACT FROM AUTHOR]

Reflective thinking and learning skills are essential for engineers in the knowledge economy. This paper describes an approach to develop these and other transferable skills through individual and collaborative reflective learning using open-source software. The learning activities and an open-source e-portfolio system called Dotfolio were tested by freshman engineering students. Findings from a survey-based study, which investigated students' beliefs about reflective learning and their expectations and experiences related to the task and open-source tool, are reported. From the be- ginning of the semester the students understood the significance of reflective learning and chose to work with the tool. However, they were less positive about the collaboration with peers during this activity. At the end of the semester, students were significantly more positive about the tool, but even more negative about the collaboration. The main problems encountered by the tutors and learners were plagiarism and a tension between the privacy of students' reflections and knowledge sharing. The open-source modular architecture allowed for the use of student and tutor feedback for the addition of new features that addressed their concerns. [ABSTRACT FROM AUTHOR]