Electromagnetic band‐gap structured printed antennas: A feature‐oriented survey

Wireless communication systems are playing an important role in different sectors of human society. Printed antennas are considered as the critical enabling technologies for these systems. The technology related to the design and development of printed antennas have been continuously improved from the structural view of configuration to antenna features improvement. Electromagnetic bandgap (EBG) structures have played a significant role in improving the features of printed antennas. In this paper, authors have restricted a feature–oriented comprehensive survey on EBG‐structured printed antennas. This type of survey is primarily required for the beginner working on EBG structures/EBG‐structured printed antennas. Such a survey process is rarely carried out in the open literature to the best of authors' knowledge. The proposed survey process is confined only to five different feature classifications; bandwidth improvement, gain improvement, dual‐band/multi‐band characteristics, band‐notch characteristics, and compact and low profile, respectively.     

Estimating the number of components with defects post‐release that showed no defects in testing

Components that have defects after release, but not during testing, are very undesirable as they point to ‘holes’ in the testing process. Either new components were not tested enough, or old ones were broken during enhancements and defects slipped through testing undetected. The latter is particularly pernicious, since customers are less forgiving when existing functionality is no longer working than when a new feature is not working quite properly. Rather than using capture–recapture models and curve‐fitting methods to estimate the number of remaining defects after inspection, these methods are adapted to estimate the number of components with post‐release defects that have no defects in testing. A simple experience‐based method is used as a basis for comparison. The estimates can then be used to make decisions on whether or not to stop testing and release software. While most investigations so far have been experimental or have used virtual inspections to do a statistical validation, the investigation presented in this paper is a case study. This case study evaluates how well the capture–recapture, curve‐fitting and experience‐based methods work in practice. The results show that the methods work quite well. A further benefit of these techniques is that they can be applied to new systems for which no historical data are available and to releases that are very different from each other. Copyright © 2002 John Wiley & Sons, Ltd.     

Computers that recognise and respond to user emotion: theoretical and practical implications

Prototypes of interactive computer systems have been built that can begin to detect and label aspects of human emotional expression, and that respond to users experiencing frustration and other negative emotions with emotionally supportive interactions, demonstrating components of human skills such as active listening, empathy, and sympathy. These working systems support the prediction that a computer can begin to undo some of the negative feelings it causes by helping a user manage his or her emotional state. This paper clarifies the philosophy of this new approach to human–computer interaction: deliberately recognising and responding to an individual user's emotions in ways, that help users meet their needs. We define user needs in a broader perspective than has been hitherto discussed in the HCI community, to include emotional and social needs, and examine technology's emerging capability to address and support such needs. We raise and discuss potential concerns and objections regarding this technology, and describe several opportunities for future work.     

Fast simulation‐driven feature‐based design optimization of compact dual‐band microstrip branch‐line coupler

Design of miniaturized microwave components is a challenging task. On one hand, due to considerable electromagnetic (EM) cross‐couplings in highly compressed layouts full‐wave EM analysis is necessary for accurate evaluation of the structure performance. Conversely, high‐fidelity EM simulation is computationally expensive so that automated determination of the structure dimensions may be prohibitive when using conventional numerical optimization routines. In this article, computationally efficient simulation‐driven design of a miniaturized dual‐band microstrip branch‐line coupler is presented. The optimization methodology relies on suitably extracted features of a highly nonlinear response of the coupler structure under design. The design objectives are formulated in terms of the feature point locations, and the optimization is carried out iteratively with the linear model of the features utilized as a fast predictor. The entire process is embedded in the trust‐region framework as convergence safeguard. Owing to only slightly nonlinear dependence of the features on the geometry parameters of the circuit at hand, the optimized design satisfying prescribed performance requirements is obtained at the low computational cost of only 24 high‐fidelity EM simulations of the structure. Experimental validation of the fabricated coupler prototype is also provided. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:13–20, 2016.     

A Design Thinking Rationality Framework: Framing and Solving Design Problems in Early Concept Generation

The concept of “Design Thinking” opens up debate regarding the prevalent human–computer interaction design practice. This article focuses specifically on the cognitive processes of designers during their early design activities. Two groups of designers—experts and novices—were asked to develop a fictitious vacuum cleaner. We then examined the different ways in which these groups manage their design thinking processes and how the groups choose design concepts. The empirical study revealed that expert designers are effective at framing design problems. They make quick decisions (through the use of the affect heuristic) but are more wedded to their own previously developed design concepts, which they do not change in subsequent design stages. In contrast, novice designers are less skilled in framing new design problems but better able to renounce their initial design concepts. These diverse design thinking approaches are linked to potential problems. We then discuss how to address these concerns in conjunction with empathy for the artifact (i.e., artifact empathy via the mediated self) or user (i.e., user empathy via the simulated self), problem framing with second-order semantic connotations, and irrationality when analyzing design solutions. Finally, we propose a design thinking rationality framework that can establish a designer's view of design activities and thereby assist designers educated in both creative and rational design decisions.     

Social facilitation effect in search and decision‐making components of visual inspection

This study aimed to examine the effect of social presence on the performance of the search and decision‐making components of visual inspection. A within‐subject design experiment was conducted. Participants performed easy and difficult search and decision‐making tasks in alone and audience‐present conditions with search time, decision time, decision accuracy rates, and subjective arousal level in both components measured. Results indicated that the presence of an audience shortened (lengthened) the response time in easy (difficult) search and decision‐making components but did not influence decision accuracy rates. The social facilitation intensity in the search component was stronger than that in the decision‐making component. For both components, the performance impairment in difficult tasks was stronger than the performance improvement in easy tasks, and arousal was greater in the audience‐present condition than when working alone. The findings helped clarify the influential mechanisms of the social facilitation effect in visual inspection tasks.     

MEMS variable‐capacitor phase shifters part I: Loaded‐line phase shifter

This article describes the design and characterization of a continuously variable loaded‐line phase shifter using micro‐electro‐mechanical system (MEMS) variable capacitors as phase shifting components. The design and characterization of micro‐electro‐mechanical system (MEMS) variable capacitors for operation at 26.5 GHz is described. A lumped‐element model is obtained from measurements and physical consideration. Experimental results show a capacitance‐tuning ratio of 3.7:1. The capacitor's characterization results are used for designing the phase shifter. A phase shift of 40.5° at 26.5 GHz for a loaded‐line type has been measured. There is good agreement between simulated and measured results. A companion article (Part II) describes the application of these variable capacitors to the design of reflection‐type phase shifters. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 321–337, 2003.     

OPTIMAL MECHANISM DESIGN AND DYNAMIC ANALYSIS OF A 3‐LEG 6‐DOF LINEAR MOTOR BASED PARALLEL MANIPULATOR

This paper presents the optimal mechanism design and dynamic analysis of a prototype 3‐leg 6‐DOF (degree‐of‐freedom) parallel manipulator. Inverse kinematics, forward kinematics, inverse dynamics and working space characterizing the platform motion are derived. In the presented architecture, the base platform has three linear slideways individually actuated by a synchronous linear servo motor, and each extensible vertical link connecting the upper and base platforms is actuated by an inductive AC servo motor. The linear motors contribute high‐speed movements to the upper platform. This kind of architecture using hybrid (linear and AC) motors yields high level performance of motions, especially in the working space. The novel result of maximal working angles is the significant contribution of this architecture. The Taguchi Experimental Method is applied to design the optimal mechanism of the platform system, and the result is used as the actual data to build this system.     

Fixed‐structure robust controller design for chatter mitigation in high‐speed milling

Chatter is an instability phenomenon in high‐speed milling that limits machining productivity by the induction of tool vibrations, inferior machining accuracy, noise, and wear of machine components. In this paper, a fixed‐structure active chatter control design methodology is proposed, which enables dedicated shaping of the chatter stability boundary such that working points of higher machining productivity become feasible while avoiding chatter. The control design problem is cast into a nonsmooth optimization problem, which is solved using bundle methods. Using this approach, fixed‐structure dynamic (delayed) output feedback controllers can be synthesized. Distinct benefits of this approach are the a priori fixing of the controller order, the limitation of the control action, and the fact that no finite‐dimensional model approximations and online chatter estimation techniques are required. All these benefits are important in milling practice. Representative examples illustrate the power of the proposed methodology in terms of increasing the chatter‐free depth of cut, thereby enabling significant increases in machining productivity. Copyright © 2014 John Wiley & Sons, Ltd.     

Multipolarization antenna design and analysis of on‐body communication

On‐body communications show highly polarization selectivity in both radio channels and antennas due to the complex body coupling and scattering effects, and full‐space dimension link distribution. To mitigate the polarization variation of on‐body communication links, multipolarization antennas are proposed to adaptively capture the on‐body channel polarization components. In this article, a tri‐polarization antenna design is introduced with its performance evaluated on a simplified three‐layered human chest model including skin, fat, and muscle tissues. The return loss, frequency response, and the radiation pattern of designed antenna are found to be affected by the relative orientation and distance between the antennas and the trunk, indicating the necessity of the antenna emplacement optimization for realistic on‐body communication devices.     

Computer‐Aided Ergonomic Analysis for Assembly Unit of an Agricultural Device

In many applications, those who work on assembly processes are required to work in nonergonomic stances. Incorrect positions may cause strain and persistent problems. In addition, strain in workers’ bodies also has a negative effect on labor productivity. Ergonomics should be applied to avoid this kind of negative impact on workers’ health as well as productivity. Ergonomics introduces the basic principles of system productivity and human‐machine‐environment relationship. With a series of computer‐aided ergonomics analysis (CAEA), necessary precautions can be taken in advance by determining the undesirable stances. Through CAEA, productivity for machinery and comfort for people can be ensured by creating an efficient working environment without causing health problems for workers who work in production. In this study, in an agricultural equipment producing company, current working positions of a worker carrying out tasks during the assembly of wheel hay rakes, have been evaluated via the CATIA Ergonomic Analysis Module. On the basis of the results, the design of the assembly unit was ergonomically improved. As a result of the improvement in the working environment, unfavorable stance positions were avoided and production time was decreased by 60%.     

DRAMA MANAGEMENT AND PLAYER MODELING FOR INTERACTIVE FICTION GAMES

A growing research community is working toward employing drama management components in story‐based games. These components gently guide the story toward a narrative arc that improves the player's gaming experience. In this article we evaluate a novel drama management approach deployed in an interactive fiction game called Anchorhead. This approach uses player's feedback as the basis for guiding the personalization of the interaction. The results indicate that adding our Case‐based Drama manaGer (C‐DraGer) to the game guides the players through the interaction and provides a better overall player experience. Unlike previous approaches to drama management, this article focuses on exhibiting the success of our approach by evaluating results using human players in a real game implementation. Based on this work, we report several insights on drama management which were possible only due to an evaluation with real players.     

Converting command‐line applications into binary components

A binary component is a separately compiled program that can be used as a part of a larger program. Binary components generally conform to an accepted technology such as JavaBeans or ActiveX, and generally support a rich program interface containing properties, methods and events. Binary components are generally used in a graphical user interface (GUI) environment. There are a number of benefits to be realized by converting command‐line software into binary components. The most important of these is that GUI environments are more popular and more familiar to most people than command‐line environments. Using binary components can greatly simplify a GUI implementation, to the point where it is only slightly more complicated than a typical command‐line implementation. However there are benefits that go beyond mere convenience. Binary components have much richer interfaces than command‐line programs. Binary components are service‐oriented rather than task‐oriented. A task‐oriented program has a main routine that is devoted to accomplishing a single task. A service‐oriented component has no main routine or main function, but instead provides a variety of services to its clients. Binary components can be easily integrated with one another, which permits a design where each major feature of an application is implemented in a different component. Such a design encourages software reuse at the component level and facilitates low‐impact feature upgrades. We first delineate a design‐pattern‐based methodology for converting command‐line programs into components. We then illustrate these principles using two projects, a simulation system for digital circuits, and a data generation system for software and hardware testing. Copyright © 2005 John Wiley & Sons, Ltd.     

Building design‐time and run‐time knowledge for QoS‐based component assembly

Modern software systems are required to dynamically adapt to changing workloads, scenarios, and objectives and to achieve a certain Quality of Service (QoS). Guaranteeing QoS requirements is not trivial, as run‐time uncertainty might invalidate the design‐time rationale, where software components have been selected by means of off‐line analysis. In this work, we propose a QoS‐based feedback approach that makes a combined use of design‐time predictions and run‐time measurements to manage QoS data over time and support software architects while selecting software components that best fit QoS requirements. We illustrate the feasibility and efficacy of the approach on a case study, where the quantitative evaluation shows how the analysis effectively identifies the sources of QoS violations and indicates possible solutions to achieve QoS requirements.     

Display panel design of a general utility helicopter by applying quantitative and qualitative approaches

The flight deck is the ultimate human–machine interface application. It uses human senses of touch and sight in a safety‐critical situation. Display systems, present on a flight deck, are complex environments causing excessive mental workload, and the consequences of errors can be catastrophic. To prevent any human error, a user‐friendly display panel must be designed. In this research the best natural dialog between the crew and interface is considered while reflecting user perspective to design by applying quantitative and qualitative approaches; in this way, proper positions of analogue indicators on the front of the display panel are determined. Multi‐Criteria Decision Making algorithms are employed as a quantitative approach. To test whether the decision‐making preferences are consistent with a quasi‐concave, a quasi‐convex, and a linear utility function, a combined algorithm is applied. Due to the form of utility function, an algorithm finding the most preferred alternative of decision making is used. The aim of this approach is to find an order in which to locate each indicator to suitable classes. Card‐Sorting methodology is used for the qualitative research of the same problem. Results of two different approaches are compared. © 2009 Wiley Periodicals, Inc.     

Human performance assessment of a single air traffic controller conducting multiple remote tower operations

The innovative concept of multiple remote tower operations (MRTO) can maximize cost savings by applying video panorama‐based remote tower working positions, which can facilitate fewer air traffic controllers (ATCO) to provide the air traffic services (ATS) function for more airports. Five subject‐matter experts, qualified remote tower ATCOs, participated in this research work by applying the human error template (HET) and comparing workload between physical tower operations and MRTO using NASA‐TLX (Task Load Index). The results demonstrate that augmented visualization provided sufficient technical support for a single ATCO to perform tasks originally designed to be performed by four ATCOs, however, the demands of the associated multiple tasks induced significant workload. There were significant differences in ATCOs’ mental demand, temporal demand, effort, and frustration between MRTO and physical tower operations. This innovative technology may induce human–computer interaction (HCI) issues that impact ATCO's perceived workload. This creates a need for further research on how to manage ATCO's workload in a multiple remote tower environment. This research work provided scientific evidence that MRTO can achieve the objectives of Single European Sky Air Traffic Management Research program. The findings can be applied to both ATCO training design and remote tower system design.     

Numerically efficient algorithm for compact microwave device optimization with flexible sensitivity updating scheme

An efficient trust‐region algorithm with flexible sensitivity updating management scheme for electromagnetic (EM)‐driven design optimization of compact microwave components is proposed. During the optimization process, updating of selected columns of the circuit response Jacobian is performed using a rank‐one Broyden formula (BF) replacing finite differentiation (FD). The FD update is omitted for directions sufficiently well aligned with the recent design relocation. As the algorithm converges, the alignment threshold is gradually reduced so that the condition for using BF becomes less stringent. This allows for further reduction of the number of EM simulations involved in the optimization process. The presented flexible Jacobian update scheme allows for considerable reduction of the computational cost with only slight degradation of the design quality. Robustness of the presented algorithm is validated through multiple optimization runs from random initial designs. The verification experiments are conducted for a range of microwave components, including a compact microstrip coupler as well as a three‐section compact microwave resonant cell‐based impedance transformer. The effects of the alignment threshold value on the computational efficiency of the algorithm and the design quality are investigated. Significant savings reaching 50% as compared to the reference algorithm are demonstrated.     

Improved trust‐region gradient‐search algorithm for accelerated optimization of wideband antenna input characteristics

Full‐wave electromagnetic (EM) simulation models are ubiquitous in carrying out design closure of antenna structures. Yet, EM‐based design is expensive due to a large number of analyses necessary to yield an optimized design. Computational savings can be achieved using, for example, adjoint sensitivities, surrogate‐assisted procedures, design space dimensionality reduction, or similar sophisticated means. In this article, a simple modification of a rudimentary trust‐region‐embedded gradient search with numerical derivatives is proposed for reduced‐cost optimization of input characteristics of wideband antennas. The approach exploits information and history of relative changes of the design (as compared with the trust region size) during algorithm iterations to control the updates of components of the antenna response Jacobian, specifically, to execute them only if necessary. It is demonstrated that the proposed framework may lead to over 50% savings over the reference algorithm with only minor degradation of the design quality, specifically, up to 0.3 dB (or <3%). Numerical results are supported by experimental validation of the optimized antenna designs. The presented algorithm can be utilized as a stand‐alone optimization routine or as a building block of surrogate‐assisted procedures.     

A state‐of‐art review on band‐notch characteristics in UWB antennas

Ultra‐wideband technology has experienced a rapid growth over the last decade for its contribution in different sectors of human society. Printed antennas are considered as preferred platform for implementing this technology because of its alluring characteristics like light weight, low cost, ease of fabrication, integration capability with other systems, etc. Antennas developed for ultra‐wideband applications are desired to have notch characteristics for avoiding interference with other existing radio communication systems. The techniques related to design and developments of printed band‐notched antennas are continuously upgraded for improving the antenna performance. In this article, a comprehensive review has been carried out on ultra‐wideband antennas with band notch characteristics proposed in around last decade. The band notched UWB antennas available in the literature have broadly been classified into five different categories based on their notch characteristics like single band‐notch, dual band‐notch, triple band‐notch, quad/multiple band‐notch, and reconfigurable/tunable band‐notch, respectively. This review exercise may be helpful for beginners working on ultra‐wideband band‐notched antennas and also such a review process is not available in the open literature to the best of author's knowledge.     

Analysis of scalable two‐π equivalent‐circuit model for on‐chip spiral inductors

High‐accuracy inductor model is vital for the success of RF/mm‐wave circuit design. In this article, the development of two‐π scalable model with four ladder skin effect structure has been described in detail. For the scalable compact circuit modeling, a set of formulas by which all of the compact circuit elements can be calculated according to the components geometric dimensions and process parameters will be given. The proposed modeling method is regarded as full scalable as all the component parameters are calculated by physical equations or revise equations. A series of spiral inductors with various geometries have been fabricated with 0.13 μm SiGe BiCMOS aluminum process to verify the model. Excellent agreements are obtained between the measured data and calculation form the proposed model up to frequencies above self‐resonant. This scalable 28‐element two‐π model enables to accurately characterize RF behaviors of on‐chip spiral inductors and optimize the inductor performance. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:93–100, 2015.