Search

The editor reflects on the special issue of the periodical which is based on the 2012 International Microwave Symposium held on June 17-22, 2012 in Montreal, Quebec. He mentions that due to increased number of submissions to the special issue, it has been divided into two issues the first one was published in December 2012, and the next one in January 2013. He adds that the aim behind including conference papers in the issue is to present results that might help improve engineering designs.

Torsional oscillations greatly affect performance and. determine the bandwidth (BW) and damping of speed loops. Backlash due to gear reducers can also contribute to the triggering of oscillations, especially when the drive runs at very low load torque. This paper presents a detailed evaluation of these effects in typical electromechanical drive trains applied to paper machine sections. The cases evaluated consider torsional oscillations in two-mass and three-mass systems, and the effect of shaft diameter and length on the resonant frequencies of three typical paper machine sections. Time-domain response plots are evaluated to show the effect of speed response overshoot, reducer backlash, and step or ramp speed commands. Based on these results, mechanical design guidelines are given for the most significant drive train components in order to minimize torsional oscillations of the speed-controlled drive system. [ABSTRACT FROM AUTHOR]

In this paper, a variation of the congestion situation is considered and a new game, the congestion game with player-specific (CGPS) utility functions, is proposed. This paper is motivated by some application scenarios that rule out the possibility of employing the existing game model to study such congestion situations. The CGPS game is characterized by adding a player-specific term and a weighted parameter with respect to the utility function. By using the semitensor product of matrices, the algebraic representation of the CGPS game is given and the existence of the weighted potential function is proved. Finally, the results are applied to solve the service chain composition problem in network function virtualization (NFV) and to analyze the effect of player-specific function on service chain configuration in NFV. Note to Practitioners—This paper is motivated by resource allocation problems in congestion networks where strategic users behave selfishly and aim at optimizing their own individual utility in the absence of a central controller. Compared with the centralized algorithms of poor reliability and scalability, game-theoretic control provides a promising distributed approach for resource allocation. In the game-theoretic framework, the existence and seeking of the desired solution are important issues. In this paper, a novel model is established to extend the utility functions space guaranteeing the existence of the solution. The developed utility design is used to capture users’ different sensitivities to the effects of the network system. Simultaneously, it is more meaningful from the view of engineering to design the utility functions so that the desirable behavior is reachable. We also give an explicit scheme to seek the desired solution. The proposed model is finally applied to the service chain composition problem in NFV, of which the aim is to find the best service chain of users that accommodates their individual requirements. The proposed model shows reliable and effective. [ABSTRACT FROM AUTHOR]

In this paper, we apply a level-set (LS) topological optimization (TO) algorithm to the design of multi-material heatsinks suitable for electronics thermal management. This approach is intended to exploit the potential of metal powder additive manufacturing technologies, which enable the fabrication of complex designs. This paper details the state-of-the-art in TO before defining a numerical framework for optimization of two-material and three-material based heatsink designs. The modeling framework is then applied to design a pure copper and a copper–aluminum heatsink for a simplified electronics cooling scenario and the performance of these designs are compared. The benefits and drawbacks of the implemented approach are discussed, along with enhancements that could be integrated within the framework. A benchmarking study is also detailed, which compares the performance of topologically optimized heatsink against a conventional pin-fin heatsink. This is the first time that TO methods have been assessed for multi-material heatsink design where both conduction and convection are included in the analysis. Hence, the reported paper is novel in its application of a state-of-the-art LS topology optimization algorithm to design multi-material structures subject to forced convective cooling. This paper is intended to demonstrate the applicability of TO to the design of multi-material heatsinks fabricated using additive manufacturing processes and succeeds in this objective. This paper also discusses challenges, which need to be addressed in order to progress this modeling as a design approach for practical engineering situations. The presented methodology is able to design thermal management structures from a combination of aluminum and copper that perform similar to pure copper but utilizing less expensive materials, resulting in a cost-benefit for electronics manufacturers. [ABSTRACT FROM AUTHOR]

This paper has introduced two important indexes, turn-off surge voltage (TSV) on power switch and peak positive pole potential (PPPP) of storage batteries, which can be used to evaluate switching transient process of high-voltage energy storage system. Research on them is of great significance to power switch choice and high-voltage isolation design in engineering applications. Power switch response process at the turning off moment and transient process in freewheel stage have been analyzed by the established small-signal model of single power switch; then, a power switch test platform for hybrid energy storage system was built to verify it. Taking pulsed-power supply charging device with a novel inductor of low resistance and high inductance as a research object, this paper has analyzed dynamic process of the TSV and the PPPP at the turning off moment through establishing state space model of the whole system. Comparison shows that the numerical curves match the simulated curves well. Finally, the exactness of the employed model has been further verified in two pulse capacitor charging experiments. [ABSTRACT FROM AUTHOR]

This paper presents a seven-port modulator capable of switching the polarization state of the transmitting signal. Similar to the six-port modulator, the proposed device modulates the carrier signal through the reflection coefficients generated by four variable loads. The additional seventh port allows feeding two antennas or a dual-port antenna. The loads control both the complex envelope and the polarization of the transmitted carrier signal. The mathematical model of the device, developed in this paper, is applied to analyze its performance and different modes of operation. For validation, a prototype is manufactured for a center frequency of 1575.42 MHz. It is used to generate M-quadratic-amplitude modulation at different polarizations. The signals recorded at the output of the prototype show good agreement with the values predicted by the model. [ABSTRACT FROM AUTHOR]

Production systems include both discrete part and batch operations, where an individual part is manufactured in a discrete operation, and a group of parts are processed simultaneously, i.e., in a batch, on one machine for a batch operation. Many manufacturing industries, such as battery, aircraft, and automotive, consist of mixed batch and discrete part operations, referred to as batch-discrete lines. Although such operations are widely encountered, analytical studies of these systems are limited in current literature. In this paper, a systems approach is presented to model and analyze batch-discrete lines. First, a Bernoulli machine reliability model for a two-machine batch-discrete system is introduced. Using a virtual buffer to represent the batch processing feature, performance evaluation formulae are derived and system properties are investigated. Using them, improvement analyses and bottleneck identification are presented. Then, the model is extended to systems with a quality inspection device under different control policies. To illustrate the applicability of the model, a case study in a composite part production process is described. Such a work delivers a quantitative tool for production engineers and managers to design, analyze, and improve batch-discrete manufacturing systems. Note to Practitioners—Many manufacturing systems in aircraft, automotive, battery, medical device, and defense industries include both batch operation and discrete part processing machines. In a batch operation, multiple parts are manufactured simultaneously on a batch machine, while a single part is made in a discrete part machine. Production lines with mixed batch and discrete part operations are named as batch-discrete systems. Analysis and improvement of such systems are critical to ensure high productivity and quality. However, accurate modeling and analysis of batch-discrete systems are lacking in current literature. To bridge this gap, a novel methodology is presented in this paper. Using a Bernoulli reliability machine model with a virtual buffer concept, performance measures are derived for batch-discrete two-machine lines, as well as the reversed discrete-batch lines. Then system properties, such as monotonicity, interchangeability, and reversibility, are investigated, followed by improvement analysis under constraints and bottleneck analysis. By extending to systems with quality inspections, two quality control policies, to scrap either the current batch or the whole inventory after detecting a degraded part, are studied. In addition, a case study of heating (batch) and trimming (discrete) operations in composite panel production lines is presented, and improvement strategies are investigated, to illustrate how to apply the model and analysis in practice. [ABSTRACT FROM AUTHOR]

Sliding contact of electromagnetic railgun affects launch accuracy, launch efficiency, and rail life. The research on sliding contact of electromagnetic railgun is very important to the theory and engineering design. However, the whole process of electromagnetic launch is high speed and big current and high heat. The state of sliding contact is complicated. The whole process is also transient process. The stage division of sliding contact is vague, and there is no definite definition about stage division. In this paper, the theoretical analysis of sliding electric contact process is introduced, and the design test is carried out to verify it. The whole launch process of electromagnetic railgun is divided into three stages: dry friction contact, liquefied layer contact, and high-speed unstable contact. The line density 15 kA/mm is defined as the critical point between dry friction stage and liquefaction stage. The armature speed 1300 m/s is defined as critical point between the liquefied contact layer and the high-speed unstable contact stage, which provides reference for the study of sliding contact in the future. [ABSTRACT FROM AUTHOR]

The sliding electrical contact performance of the electromagnetic railgun is the main factor affecting the launch accuracy, launch efficiency, and working life of the electromagnetic railgun. The objective evaluation of the sliding electrical contact performance of the electromagnetic railgun is crucial for the research of the electromagnetic railgun theory and engineering design. Because the sliding electrical contact process of the electromagnetic rail gun is complex, the mechanism and performance requirements of the launcher in different phases are different, so it is difficult to evaluate according to the unified standard. In this paper, the whole launch process is divided into three phases: dry friction, liquefaction layer, and high-speed instability. The sliding electrical contact mechanism of these three phases is analyzed separately, and the evaluation model is established, respectively. Then, the theoretical analysis, expert evaluation, and experimental data statistics are used to comprehensively determine the weight system of the three phases. Finally, the comprehensive evaluation model of the three phases is established. The validity of the above-mentioned model is verified by the actual launch test. The evaluation method of this model has practical significance for the scientific research, engineering design, and model development of the electromagnetic rail gun. [ABSTRACT FROM AUTHOR]

The objective of this paper is to advance the state of the art of aggressive space mapping (ASM) by demonstrating how, for resonant structures, and microwave filters in particular, an ASM-based optimization procedure may converge to the desired target performance in just one step. This behavior is first justified in physical terms, using the electromagnetic cavity perturbation theory, and is then investigated numerically. Several practical filter design demonstrations are also presented. This paper is concluded with a conceptual definition of Space Alignment in the context of ASM. [ABSTRACT FROM AUTHOR]

Error injection has become critically important for testing the reliability of newly designed hardware systems. Evaluating how a design under test (DUT) reacts to different error-injection methodologies is essential for verification engineers to design dependable universal verification methodology (UVM) scoreboards for error-detection purposes. The first main contribution of this paper is to decide on the feasibility and compatibility of some error-injection techniques when used with networks-on-chip (NoC) platforms for simulation and hardware emulation environments. We target a UVM-based error-injection and detection environment with reusable components. Proposed techniques, introducing both positive and negative test scenarios, are applied to two examples of NoC components: 1) a base router and 2) Daniel router. Base router is a simple case study to prove proposed schemes, whereas Daniel router is a complex reconfigurable open-source case study. Daniel router provides the ability to change router architecture with some parameters and applied algorithms. The second main contribution of this paper is to integrate a full UVM environment with various verification approaches. Target approaches include error injection and detection using reusable and generic UVM environment and components for NoC. Network response is inspected according to error type and methodology. Finally, the proposed UVM environment is used to test and verify an ${N}\,\,{\times }\,\,{N}\,\,2$ -D network composed of base routers or Daniel routers. [ABSTRACT FROM AUTHOR]

The terms module and modularity are not part of the technical taxonomy in any of the systems engineering standards, which do not regard a module as a part of the formal system breakdown structure. In this paper, we redefine the term module as a unit composed of a set of components with a set of specific interfaces. This unit serves one or more purely nonfunctional goals, such as flexibility, evolvability, manufacturability, testability, and maintainability. According to this definition, a configuration item, a subsystem, an assembly, a subassembly, or a component can all be regarded as modules as they can serve nonfunctional goals. The important assertion here is that a module's boundaries do not necessarily coincide with those dictated by the functional or spatial system decomposition and hierarchy. The aim of this paper is to lay the foundations for the future standardization of various engineering design processes based on modularity for nonfunctional benefits. A clear definition of the terms module and modularity can assist systems designers and developers to optimize the value of a modular system. This research highlights the present inconsistencies in the field of modular system design and puts forward some critical questions, which will shape the future research into this field. [ABSTRACT FROM AUTHOR]

Named entity recognition (NER) is the task to identify mentions of rigid designators from text belonging to predefined semantic types such as person, location, organization etc. NER always serves as the foundation for many natural language applications such as question answering, text summarization, and machine translation. Early NER systems got a huge success in achieving good performance with the cost of human engineering in designing domain-specific features and rules. In recent years, deep learning, empowered by continuous real-valued vector representations and semantic composition through nonlinear processing, has been employed in NER systems, yielding stat-of-the-art performance. In this paper, we provide a comprehensive review on existing deep learning techniques for NER. We first introduce NER resources, including tagged NER corpora and off-the-shelf NER tools. Then, we systematically categorize existing works based on a taxonomy along three axes: distributed representations for input, context encoder, and tag decoder. Next, we survey the most representative methods for recent applied techniques of deep learning in new NER problem settings and applications. Finally, we present readers with the challenges faced by NER systems and outline future directions in this area. [ABSTRACT FROM AUTHOR]

The twenty-one papers in this special section focus on bringing the ideas of the worldwide research community working on various disturbance/uncertainty estimation and rejection methods in different engineering sectors into common platform and to present the latest advances and developments in design methods for disturbance/uncertainty estimation, design methods for disturbance/uncertainty attenuation, stability and performance analysis, practical implementation, and various case studies of the applications of these techniques. [ABSTRACT FROM PUBLISHER]

Robust design optimization aims to find solutions that are competent and reliable under given uncertainties. While such uncertainties can emerge from a number of sources (imprecise variable values, errors in performance estimates, varying environmental conditions, etc.), this paper focuses on problems where uncertainties emanate from design variables. In commercial designs, being reliable is often of more practical value than being globally best (but unreliable). Robust optimization poses three key challenges: 1) appropriate formulation of the problem ; 2) accurate estimation of the “robustness” measure; and 3) efficient means to identify the set of tradeoff robust solutions with an affordable computational cost. In this paper, four different problem formulations for robust optimization are presented and analyzed. The proposed formulations offer a set of tradeoff solutions with robustness from two perspectives—feasibility robustness, i.e., robustness against failure and performance robustness, i.e., robustness assuring good performance. The approach also provides means to identify critical constraints or performance functions that affect the overall robustness. The problem is posed as a many-objective optimization problem and a decomposition-based evolutionary approach is used for solving it. The performance of the proposed approach and the consequences of using different formulations are illustrated using two numerical examples and four engineering problems. [ABSTRACT FROM PUBLISHER]

In this paper, the impact of donor and acceptor states at the Schottky interface of fully recessed AlGaN/GaN Schottky diode is physically modeled using device TCAD and detailed experiments. This allowed us to develop physical insights into recessed AlGaN/GaN diode’s reverse breakdown, reverse leakage, and ON-state performance as a function of interface states and provided design guidelines to engineer fully recessed AlGaN/GaN Schottky diode for the maximum reverse breakdown and least reverse leakage without compromising its ON-state performance. It has been observed that donor states are responsible for high reverse leakage and reduced breakdown performance in Schottky diodes. On the other hand, the presence of acceptor states at the interface improves the diode leakage and breakdown voltage. Experiments involve a number of dry and wet surface treatments to: 1) validate computational findings and 2) find ways to cure or passivate donor states affected Schottky interface/recessed region. The introduction of acceptor traps at the Schottky interface has been proposed and experimentally verified using the Fluorine implant to cure donor state-affected Schottky interface, which improves the breakdown and reverse leakage characteristics significantly. [ABSTRACT FROM AUTHOR]

Multi-phase topology optimization (TO) is able to determine the optimal distribution of two or more different materials in combination under some volume or weight constraints and is a very common problem in the engineering design area. To perform multi-phase TO, a new methodology based on the multi-label graph cut theorem is proposed in this paper. More specifically, the multi-label expansion move included in the theorem is able to solve the multi-phase TO problem without requiring a large amount of memory and time. According to the numerical results as reported, the proposed methodology can find the optimal topology of a multi-phase materials distribution with a significant improvement in the performance parameter. [ABSTRACT FROM AUTHOR]

The paper presents a novel approach for a gradient-less free-form optimization of engineering problems. The main feature of the approach is that it enables optimization of the engineering problems without calculation of an adjoint problem. This provides a fast and robust optimization of 3-D problems in practical engineering. In this paper we present the basic idea behind this technique followed by the example of the indirect optimization of the TEAM benchmark problem No. 25. [ABSTRACT FROM AUTHOR]

Reliability and cost are two most important issues in network design optimization that is extensively applied into various optimization problems such as supply chain network design, telecommunication network design, and transportation engineering. This paper proposes an efficient deterministic optimization approach for solving the problem of designing a reliable network. The problem discussed in this paper considers the minimization of the total cost subject to demand, flow balance, and capacity constraints while simultaneously employing mitigation resources to reduce the risk of network failures. Such a problem is typically formulated as a nonconvex mixed-integer program that cannot be easily solved to obtain a global optimum. The proposed optimization method transforms the original nonconvex program into a mixed-integer linear program by linearization techniques and is thus guaranteed to reach a global optimum. In addition, an extended model of minimizing the total weighted loss subject to resource constraints is discussed and globally solved by the proposed method. Experimental results show that the proposed approach effectively solves the reliable network design problem with the minimal total cost or the minimal total weighted loss under an appropriate allocation of mitigation resources. [ABSTRACT FROM AUTHOR]

Successful recovery from a disrupted state to maintain optimal performance is a key feature that a resilient complex engineered system should have. In the engineering design community, the current focus of engineering resilience research is primarily directed toward improving overall system performance in the presence of likelihood failures. Little attention has been given to the study of how the system responds during and/or after the occurrence of a failure event. This paper proposes the use of control theory as a strategy to enable resilient behavior in complex engineered systems. Control theory has various benefits in its application to a resilient engineered system, with the main advantage being its ability to regulate and govern system states, even while the failure is taking place. In the context of implementation within a complex engineered system, such a controller should be designed such that, when a disturbance occurs, the controller should simultaneously be able to take timely action to correct the shift in system performance. To date, the fusion of control theory with engineering resilience has not been explored in-depth by the engineering design community. This paper, thus, presents a resilience modeling and analysis approach using fundamental control theory. The resilience of a power distribution system is employed as a case study to demonstrate the effectiveness of the proposed approach. The presented study also expects to aid in the concurrent development of resilience functions in complex engineered systems under uncertainty. [ABSTRACT FROM PUBLISHER]

Through silicon via (TSV) cross coupling can seriously degrade circuit performance of 3-D ICs if it is not considered during design. In this paper, we propose two algorithms which combine coupling-aware TSV placement with shield insertion to yield better results than either technique alone. We first introduce an algorithm for TSV placement assuming a fixed standard cell placement. The result of this algorithm is a 13% reduction in worst case coupling across all TSV pairs and a 90% reduction in the total number of TSV pairs violating an imposed coupling threshold. We then introduce a second algorithm that perturbs a given standard cell and TSV placement to improve coupling. This second algorithm yields a 17% reduction in worst case coupling and removes all coupling violations. Both algorithms cause wirelength (WL) to increase no more than 5%. Our algorithms offer a large improvement to TSV–TSV coupling at the expense of only a meager degradation of total WL, and in many designs and applications this trade-off is well justified. [ABSTRACT FROM PUBLISHER]

The article discusses various papers published within the issue including "Modeling Co-Construction Processes in a Socio-Technical Framework to Support Collaborative Engineering Design," "Collaborative Service Systems: A Mutualism-Based New Service Design Methodology," and "Maintenance Chain Integration Using Petri-Net Enabled Multi-Agent System Modeling and Implementation Approach."

The article presents highlights from the Design Automation Conference (DAC) held in June of 2007 in San Diego, California. The technical theme was automobile electronics. Keynote speakers included Lawrence Burns from General Motors Corp. and Oh-Hyun Kwon of Samsung. Out of 713 technical papers submitted, 161 were presented.

Engineering designs can involve multiple stages, where at each stage, the design models are incrementally modified and optimized. In contrast to traditional dynamic optimization problems, where the changes are caused by some objective factors, the changes in such incremental optimization problems (IOPs) are usually caused by the modifications made by the decision makers during the design process. While existing work in the literature is mainly focused on traditional dynamic optimization, little research has been dedicated to solving such IOPs. In this paper, we study how to adopt cooperative coevolution to efficiently solve a specific type of IOPs, namely, those with increasing decision variables. First, we present a benchmark function generator on the basis of some basic formulations of IOPs with increasing decision variables and exploitable modular structure. Then, we propose a contribution-based cooperative coevolutionary framework coupled with an incremental grouping method for dealing with them. On one hand, the benchmark function generator is capable of generating various benchmark functions with various characteristics. On the other hand, the proposed framework is promising in solving such problems in terms of both optimization accuracy and computational efficiency. In addition, the proposed method is further assessed using a real-world application, i.e., the design optimization of a stepped cantilever beam. [ABSTRACT FROM AUTHOR]

Since the problem of power integrity has become a critical issue that limits design performance, obtaining the supply current waveforms at early design stages is essential to achieve efficient reduction of supply noise. Therefore, a high-level current macro model is proposed by Bodapati and Najm for logic blocks to provide fast current waveform estimation at register-transfer level (RTL). However, due to the different arrival time of internal signals, modeling the supply current of the entire logic block accurately as specific fixed templates is difficult. This paper thus proposes a levelized high-level current model for logic blocks. By merging gates with similar arrival time as a super-gate and recording its current waveforms separately, obtaining more accurate supply current waveforms is possible by using a unified model, even for multipeak cases. This paper also proposes a frequency-domain waveform transformation method to consider the effects of nonideal supply resistance on the supply current waveform. As shown in the experimental results, the peak error and waveform correlation of the proposed current model are significantly improved compared to the results of the single-stage current model. Using accurate supply current waveforms can also help obtain precise IR-drop estimation in RTL simulations for early system evaluation. [ABSTRACT FROM PUBLISHER]

This paper presents the service value method (SVM) as a novel means to gather and interpret end-user needs, aspirations, and contextual factors to improve engineering design practice of energy access systems for the Global South. The method adopts a service-oriented approach and consists of a rapid and effective field exercise to gather qualitative and quantitative data from end users in focus groups. This exercise is suitable for enabling end-user participation in Global South contexts. The data are interpreted as service maps that capture end-user preferences to inform tradeoffs of different design criteria, guiding the preliminary design of the energy system. The method ensures end-user needs and contexts are integrated into the design process early on. A case study is presented, where the SVM was used to design solar nanogrids in Kenya and Bangladesh. [ABSTRACT FROM AUTHOR]

The launching process of multistage synchronous induction coilgun (MSSICG) is a complex process involving multifield coupling, so it is time-consuming to iteratively optimize its structural parameters by stochastic optimization algorithm. A nonlinear regression modeling method of MSSICG based on mainstream machine learning methods is proposed in this paper. Rooted in the current filament model (CFM) verified by prototype experiment, the sample set for training and testing could be obtained by a hybrid experimental design method. The least-squares support vector machine (LSSVM), the kernel extreme learning machine (KELM), and the eco state network (ESN) were employed to learn the training samples. In order to improve the accuracy of the prediction model, the chicken swarm optimization (CSO) was introduced to pretrain the hyperparameters of the LSSVM and the KELM as well as the parameters of the dynamic reservoir of the ESN. The results show that the predictive modeling of MSSICG based on CSO-KELM has better accuracy and generalization performance. Based on the obtained regression model, the CSO algorithm was used to optimize the structural parameters of a five-stage coilgun. It turns out that the optimization based on nonparametric model has higher computational efficiency than the optimization method which requires large-scale iterative calculation. This provides a novel idea for the engineering design of the MSSICG. [ABSTRACT FROM AUTHOR]

The sliding electrical contact performance of electromagnetic railgun is the main factor affecting the launch accuracy, launch efficiency, and working life of electromagnetic railguns. The research on the evaluation of sliding electrical contact performance of electromagnetic railgun is crucial for the research of electromagnetic railgun theory and engineering design. In this paper, a lumped evaluation model based on the normalized index of the resistance heat loss and frictional resistance loss of the electromagnetic railgun armature–rail interface is established, and the actual launch test of a certain launcher is evaluated to verify the lumped evaluation model. It can provide a reference for the theoretical and engineering application research of the sliding electromagnetic contact performance of the subsequent electromagnetic railgun. [ABSTRACT FROM AUTHOR]

This paper presents a built-in self-test (BIST)-based scheme for fault diagnosis that can be used to identify permanent failures in embedded read-only memories. The proposed approach offers a simple test flow and does not require intensive interactions between a BIST controller and a tester. The scheme rests on partitioning of rows and columns of the memory array by employing low cost test logic. It is designed to meet requirements of at-speed test thus enabling detection of timing defects. Experimental results confirm high diagnostic accuracy of the proposed scheme and its time efficiency. [ABSTRACT FROM AUTHOR]

Servo and mechanical approaches are presented in this paper with a view to minimize repeatable runout (RRO) components of track-following position error signal (PES) in high Track Per Inch (TPI) hard disk drives. Harmonics of the RRO are identified and classified in the context of real-time RRO and written-in RRO harmonics. Combination of experimental PES measurements, relative analytical models, and practical servo and mechanical design methods is presented and systematically discussed in this paper. [ABSTRACT FROM AUTHOR]

This paper presents a patient transfer apparatus between bed and stretcher. This apparatus makes it possible for the nurse to move weak, injured, or paralyzed patient from bed to stretcher, or vice versa, alone. Moreover, the suffering, stress, and uneasy feeling of the patient can be alleviated. This paper describes the specification, mechanical design, control system, and motion control of the apparatus. A special devised mechanism is developed, and a new servo system is used in this control system. The control principle and algorithm of the new servo system are proposed, and the motion-control method and safety function of the apparatus are described. The experimental results and evaluation indicated the effectiveness of this system. [ABSTRACT FROM AUTHOR]

The article presents a new method for rapid construction of large-scale executable railway models. Computer systems for railway systems suffer from poor integration and lack of explicit understanding of the large amount of static and dynamic information in the railway. It is shown in this paper, how a component-oriented approach makes it easy to construct and refine basic railway models by effective methods.

This article discusses requirements analysis, multiphase prototyping, and effective use of commercial off-the-shelf technologies to improve communication and situation awareness in nursing teams. It describes a wearable prototype with only a person-month of development time,, using existing electronic meeting technologies for its multimodal communication platform. Research questions include the type of methodologies that are useful for prototyping pervasive computing systems.

Beginning fall 2001, the Electrical Engineering Department at Texas A&M University, College Station, significantly altered the instructional philosophy of the ELEN 214 Electric Circuit Theory course by introducing more engineering design into the curriculum and adopting the WebCT-based interactive homework submission system. This paper will discuss the use of the Quiz tool within WebCT for the construction of question banks and their publication to a WebCT server. An example, deriving mathematical expressions, which describes electric circuit behavior and helps customize the homework problems to each individual student, are discussed. In other words, in a class of 200 students, each student is presented with an individual homework assignment with a unique set of problems not repeated to anyone else via WebCT. A help desk staffed by senior undergraduates assists the course students in completing the WebCT-based homework on time. WebCT is an essential ingredient in the delivery of the course. The approach presented in this paper can be adapted to any other course in engineering/science that involves mathematical calculations. So far, the course evaluations suggest that the students are more motivated and excited about electrical and computer engineering as a career. [ABSTRACT FROM AUTHOR]

This paper develops control design technology for active shape control of reflective surfaces using large spatially distributed actuator arrays. The potential applications are in astronomy, adaptive optic, beam control, space-based imaging, and other optics and imaging applications. In a very large lightweight active reflector, surface shape (figure) might be controlled by an array of actuators and sensors that counts millions of cells. The control technology discussed in this paper is scalable to these large array dimensions. This paper develops a classically motivated design methodology for distributed localized control laws of very large actuator/sensor arrays. The methodology uses standard PI-compensation, plus lags and/or notch-filters, to deal with temporal dynamics in each actuator channel. It achieves scalability to very large array sizes by imposing spatially localized fixed-form constraints on the control law structure. In this setup, the entire spatial-temporal design model can be transformed, via Laplace transforms in time and two-dimensional (2-D) discrete Fourier transforms in space, to produce a family of dynamic systems whose closed-loop characteristics can be subjected to standard classical control-engineering specifications, including stability, performance, and robustness. These specifications can be satisfied for all members of the family by solving linear programs (LPs) to find parameters of the fixed-form structure. The veracity of this methodology is illustrated with a design example loosely resembling an actively controlled reflector whose local deformations are controlled by a hexagonal array of actuator/sensor cells. [ABSTRACT FROM AUTHOR]

This paper will explore applied risk analysis techniques used during the development and application of industrial machines. The method discussed is used to help define the hazard to be addressed, apply a quantitative value to the hazard, evaluate the applied quantitative value with consistent benchmarks, record the mitigating next steps or record that the estimated residual risk is below the established benchmark and that the process is complete. The method will include hazards identified from the machine design and those that occur from the mitigating methods. This paper, while identifying some resources, does not address generic risk analysis technology. [ABSTRACT FROM AUTHOR]

This paper presents a formal systematic optimization process to plate-fins heat sink design for dissipating the maximum heat generation from electronic component by applying the entropy generation rate to obtain the highest heat transfer efficiency. The design investigations demonstrate the thermal performance with horizontal inlet cooling stream is slightly superior to that with vertical inlet cooling stream. However, the design of vertical inlet stream model can yields to a less structural mass (volume) required than that of horizontal inlet stream model under the same amount of heat dissipation. In this paper, the constrained optimization of plate-fins heat sink design with vertical inlet stream model is developed to achieve enhanced thermal performance. The number of fins and the aspect ratio are the most responsive factors for influencing thermal performances. The heat sink used on AMD Thunderbird 1-GHz processor has been examined and redesigned by presenting optimization methodology. The optimal thermal analysis has a very good agreement to the both of vendors' announced information and using simulation of parabolic hyperbolic or elliptic numerical integration code series (PHOENICS). The optimum design that minimizes entropy generation rate in this paper primarily applied three criteria for plate-fins heat sink optimal design: 1) formal constrained nonlinear programming to obtain the maximum heat dissipation; 2) prescribed heat dissipation; 3) prescribed surface temperature. As a result, the thermal performance can be notably improved; both the sink size and structural mass can apparently be reduced through the presented design method and process. This analysis and design methodology can be further applied to other finned type heat sink designs. [ABSTRACT FROM AUTHOR]

Drastic increases in the scale and complexity of engineered systems present many new challenges for the product development (PD) and engineering design communities. PD is characterized by the development of large, multidisciplinary, and networked systems that cannot be embraced by a single group or organization. Appropriate PD management principles can circumvent many of the difficulties that arise during the PD process. In this article, the author presents an integrative literature review that includes theories, models, and tools that can be used to manage complex PD. The review is structured around three PD analysis domains: product, people, and process. The review does not identify all the publications in any one PD domain, but instead addresses critical issues that exist within each domain and at the intersection of these domains. By reviewing these representative papers and creating a critical discussion around them, the intent is to provide an overview of the available theories, models, and tools for PD practitioners, while simultaneously identifying opportunities for future research. [ABSTRACT FROM AUTHOR]

Introduction: Teachers of English for specific purposes (ESP) face challenges when helping engineering students to comprehend discipline-specific reading materials because these students have not been exposed to engineering reading materials at the secondary-school level. This study examines how to best create Science, Technology, Engineering and Mathematics (STEM)-specific, student-friendly reading materials for engineering learners to make the transition from general topics to engineering topics comfortable. About the case: Working at affiliated colleges of Anna University, Chennai, India, we substituted reading materials for those used in textbooks to improve our students’ receptivity to reading classes. We discuss reading as a skill, the level of reading comprehension needed in the engineering context, and its relevance to technical and professional communication. Situating the case: The study focuses on the need to design materials for the engineering classroom. Methods: Our methods include a present-situation analysis to examine the challenges that teachers encounter, and analysis of qualitative feedback on the reading materials and activities introduced in the classroom. Results and discussion: The paper includes our experiences in designing reading materials: conducting the present-situation analysis, finding and designing appropriate reading materials, creating and implementing reading activities, and collecting feedback. The responses of the learners indicate that introducing STEM-specific material may increase the learners’ participation and improve their comprehension skills. Conclusion: The study shows that STEM-specific, student-friendly reading materials fostered a positive attitude and improved, high-level comprehension. [ABSTRACT FROM AUTHOR]

In this paper, we make the case for an increased focus on teaching an understanding of societal context and the integral role it plays in energy infrastructure design. Power system design education is inadequate in terms of holistic understanding of the non-technical aspects of a client-society in the development of energy infrastructure solutions. These are reflected in many failed designs, primarily designed by student engineers as part of capstone projects, senior design projects, or extra-curricular work through humanitarian-oriented programs administered by NGOs. We are developing coursework that introduces students to the complexities involved in the practice of engineering in rural communities at the international level. [ABSTRACT FROM AUTHOR]

This paper proposes a new kind of photonic crystal waveguide (PCW) called asymmetric oval-shaped-hole PCW (AOPCW). In this PCW, 20 structural parameters are considered, which provides a very flexible PCW to design. The large number of variables makes the design process of this new PCW almost impossible by the current manual try and error methods. Therefore, the AOPCW is optimized automatically by the artificial intelligence optimization technique in three phases. First, the AOPCW is optimized to maximize normalized delay-bandwidth product. Second, it is optimized with respect to two objectives: averaged of group index (\overline n_g ) and normalized bandwidth $(\Delta \omega /\omega _0)$. Third, group velocity dispersion is also considered in addition to the two objectives in the second phase, so AOPCW is optimized with respect to three objectives. In all of the three phases, a band mixing avoidance mechanism is also considered and handled. The comparative study of the optimized designs proves that the proposed AOPCW is able to substantially outperform the current PCW structures in the literature. This paper also considers and discusses time-domain simulation issues of the PCW-based optical buffer. [ABSTRACT FROM PUBLISHER]

The aim of this paper is to show the results of various experimental tests carried out on synchronous reluctance (REL) motors with different rotor geometries, as proposed in technical literature. The impact of the assistance of ferrite permanent-magnet (PM) inset in the flux barriers is considered: PM-assisted REL motors are compared with synchronous REL motors, highlighting the main benefits of the former solution. The effect of the rotor skewing and of adopting asymmetric geometries of the flux barriers to reduce the torque ripple is investigated by means of several tests. The impact of the lamination is also considered, as far as the overload capability is concerned. In addition to the experimental tests, a finite-element model is adopted to predict the performance of the motors. The predicted results are compared with the experimental ones in a wide operating range, showing a good agreement. [ABSTRACT FROM AUTHOR]

With the increasingly high demand for well-trained power systems engineers, the University of Pittsburgh has partnered with Eaton in the creation of the new Electric Power Systems Laboratory at the Swanson School of Engineering. This laboratory demands the capability to perform a wide variety of experimental procedures while providing students and researchers with a seamless working environment. To accomplish that goal, a novel lab workbench was developed. This lab workbench integrates the load banks necessary for laboratory procedures with advanced metering, controls and safety features, and contains them within a work station ideally suited for the laboratory space. This paper details the development of those lab workbenches, from concept, to design, to prototype construction, to testing. Additionally, this work describes planned classroom experiments utilizing the developed bench. Ultimately the realized workbench demonstrates its capability to be reconfigured to suit the demands of both education as well as new research projects for undergraduate and graduate studies. [ABSTRACT FROM PUBLISHER]

This paper presents a modified Damage Equalization Method with statistical features for life estimation of dielectrics. The paper postulates damage as a random variable, which resulted in establishing a relationship between the Weibull scale, shape parameters and the endurance coefficient ‘n’ of inverse power law. By the modified DEM (m-DEM), for the first time, a range of values of n for each material is proposed, which is useful for design engineers. Until now, the endurance coefficient of inverse power law and strength constant were treated as constants. Here, it is shown that these coefficients do have statistical features or variations. Experiments are conducted on oil impregnated paper and LDPE samples using accelerated step-stresses for life estimation. The results of the estimation of endurance coefficient are compared with existing methods and reasonable conclusions are drawn in favor of the proposed method. [ABSTRACT FROM AUTHOR]

Design of distributed embedded systems is a challenging task and it requires raising the level of abstraction to overcome the complexity of the design. In particular, modeling languages and semantic specification are necessary to address network description at high level of abstraction. Starting from this abstraction view, model manipulation is needed to explore various design alternatives and code generation is required for their simulation. In this paper, we propose the use of unified modeling language diagrams combined with a formal computational model as a key solution to specify requirements, generate design alternatives, and code for simulation. This paper proposes a formal framework and supporting tools to represent the application requirements, the library of network components, the environment description, and the rules to compose them. The framework allows to generate code for design validation by simulation and provides back annotation mechanism of the simulation results to refine the original model. [ABSTRACT FROM PUBLISHER]

Monolithic 3D (M3D) is an emerging technology that enables integration density which is orders of magnitude higher than that offered by through-silicon-vias. In this paper, we demonstrate that a modified 2D placement technique coupled with a post-placement partitioning step is sufficient to produce high-quality M3D placement solutions. We also present a commercial router-based monolithic intertier via insertion methodology that improves the routability of M3D ICs. We demonstrate that, unlike in 2D ICs, the routing supply and demand in M3D ICs are not completely independent of each other. We develop a routing demand model for M3D ICs, and use it to develop an O(N) min-overflow partitioner that enhances routability by off-loading demand from one tier to another. This technique reduces the routed wirelength and the power delay product by up to 7.44% and 4.31%, respectively. This allows a two-tier M3D IC to achieve, on average, 19.9% and 11.8% improvement in routed wirelength and power delay product over 2D, even with reduced metal layer usage. [ABSTRACT FROM PUBLISHER]

Binary sequence sets with asymptotically optimal auto/cross correlation peak sidelobe level (PSL) growth have been known in the literature for a long time, and their construction has been studied both analytically and numerically. In contrast, it has been a long-standing problem whether we can construct a family of binary sequences whose auto-correlation PSL grows in an optimal manner. In this paper, we devise a construction method of binary sequences with asymptotically optimal PSL growth from the sequence sets with good correlation properties. A key component of the design follows from the observation that if the PSL of the sequence set grows optimally or nearly optimally, then the PSL of the constructed binary sequence will experience a similar growth as a consequence. The proposed construction is simple-to-implement, and is shown to be accomplished in polynomial time. With such a construction, we not only bridge the gap between analytical construction and computational search, but also pave the way to settle the long-standing design problem of binary sequences with an optimal growth of the auto-correlation PSL. [ABSTRACT FROM AUTHOR]

The China fusion engineering test reactor is a new tokamak device. The central solenoid (CS) model coil, which is responsible for developing and verifying the key manufacturing methods of a superconducting magnet, is now under engineering design. The rating current of the coil is 47.65 kA and total magnetically stored energy reaches 407 MJ, so a quench protection is required to discharge this huge stored energy. This paper gives a description of the quench protection of CS model coil. The circuit of the quench protection system is designed, which consists of the direct current circuit breaker, discharge resistor, diode, and fuse. The main parameters of these components were selected. The control system of quench protection is also introduced. [ABSTRACT FROM AUTHOR]