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The purpose of this paper is to describe a modified Hilbert‐based fractal antenna for ultra wideband (UWB) wireless applications. Simulation results show excellent multi‐band characteristics for UWB wireless applications.

A Hilbert curve‐based fractal is optimised for self‐replicating, space‐filling and self‐avoiding properties. In the proposed design, the Hilbert curve is applied to a rectangle as an initial iteration and maintained for the later iterations. Additionally, a Yagi‐like strip is removed from the second iteration of the Hilbert patch and a hexagonal portion is removed from the substrate to achieve good optimization. The antenna feed is created through a micro‐strip line with a feeding section. Finally, a partial ground plane technique is used for improved impedance matching characteristics. A finite element method (FEM) is used to simulate the modified Hilbert model with commercially available Ansoft HFSS software.

The proposed antenna is miniaturized (39 mm length×30 mm width) and has multi‐band characteristics. The simulation results show that the antenna has a reflection coefficient characteristic of <−10 dB, a linear phase reflection coefficient, better than 65 percent radiation efficiency, 2.2‐4 dBi antenna gain and nearly omni‐directional radiation pattern properties over the UWB bandwidth (3.1‐10.6 GHz).

The antenna shows promising characteristics for the full 7.5 GHz UWB bandwidth. In addition, the performance is achieved by using laceration techniques on the Hilbert patch and substrate, respectively. A partial ground plane ensures impedance matching of 50 over full UWB bandwidth. The simulation analysis of the modified Hilbert fractal antenna design constitutes the main contribution of the paper.

A vertically stacked, three layer hybrid Hilbert fractal geometry and serpentine radiator-based patch antenna is proposed and characterized for medical implant applications at the Industrial, Scientific and Medical band (2.4-2.48 GHz). Antenna parameters are optimised to achieve miniaturized, biocompatible and stable transmission characteristics. The paper aims to discuss these issues.

Human tissue effects on the antenna electrical characteristics were simulated with a three-layer (skin, fat and muscle) human tissue model with the dimensions of 180×70×60 mm3 (width×height×thickness mm3). Different stacked substrates are utilized for the satisfactory characteristics. Two identical radiating patches are printed on Roger 3,010 (ε _r=10.2) and Alumina (ε _r=9.4) substrate materials, respectively. In addition, various superstrate materials are considered and simulated to prevent short circuit the antenna while having a direct contact with the metallization, and achieve biocompatibility. Finally, superstrate material of Zirconia (ε _r=29) is used to achieve biocompatibility and long-life. A finite element method is used to simulate the proposed hybrid model with commercially available Ansoft HFSS software.

The antenna is miniaturized, having dimensions of 10×8.4×2 mm3 (width×height×thickness mm3). The resonance frequency of the antenna is 2.4 GHz with a bandwidth of 100 MHz at return loss (S11) of better than −10 dB characteristics. Overall, the proposed antenna have 50 Ω impedance matching, −21 dB far field antenna gain, single-plane omni-directional radiation pattern properties and incident power of 5.3 mW to adhere Specific Absorption Rate regulation limit.

Vertically stacked three layer hybrid design have miniaturized characteristics, wide bandwidth, biocompatible, and stable characteristics in three layer human tissue model make this antenna suitable for implant biomedical monitor systems. The advanced simulation analysis of the proposed design constitutes the main contribution of the paper.

The use of choice-based, matched, and other stratified sample designs is common in auditing research. However, it is not widely appreciated that the data analysis for these studies has to take into account the non-random nature of sample selection in these designs. A choice-based, matched or otherwise stratified sample is a nonrandom sample that must be analyzed using conditional analysis techniques. We review five research streams in the auditing area. These streams include work on determinants of audit litigation, audit fees, auditor reporting in financially distressed firms, audit quality and auditor switches. Cram, Karan, and Stuart (CKS) (2009) demonstrated the accuracy of conditional analysis, compared to unconditional analysis, of nonrandom samples through the use of simulations, replications, and mathematical proofs. Papers since published have continued to rely upon questionable research, however, and it is hard for researchers to identify what is the reliability of a given work. We complement and extend CKS (2009) by identifying audit papers in selected research streams whose results will likely differ if the data gathered are analyzed using conditional analysis techniques. Thus research can be advanced either by replication and reanalysis, or by refocus of new research upon issues that should no longer be viewed as settled.

To maintain and enhance innovation performance, many firms nowadays look for resources from external sources such as strategic alliances and regional network embeddedness. While considering the important interdependencies among different alliances, research has established an alliance portfolio perspective. From an alliance portfolio perspective, firms can consciously configure the dimensions of their alliance portfolios such as partner characteristics, relational properties, or structural properties. However, within the context of alliance portfolio configuration, the role of regional networks has been largely overlooked. As most high-tech firms are regionally clustered, this is an important research gap. In addressing this gap, this study explores the link between regional network density, alliance portfolio configuration, and its contribution to firm innovation performance. We examine how regional network density and alliance partner diversity influences firm level innovation output. We also investigate the moderating effect of overall network partner status and partner diversity on the link between regional network density and innovation performance. Our empirical evidence is derived from a longitudinal quantitative study of 1,233 German biotechnology firms. We find that regional network density and alliance partner diversity has an inverted U-shape effect on firm level innovation performance. However, overall network status as well as alliance partner diversity negatively moderates the link between regional network density and innovation output. Thus, our study contributes to a better understanding of the link between regional networks, alliance portfolio configuration, and firm level innovation performance.

The Bureau of Economics in the Federal Trade Commission has a three-part role in the Agency and the strength of its functions changed over time depending on the preferences and ideology of the FTC’s leaders, developments in the field of economics, and the tenor of the times. The over-riding current role is to provide well considered, unbiased economic advice regarding antitrust and consumer protection law enforcement cases to the legal staff and the Commission. The second role, which long ago was primary, is to provide reports on investigations of various industries to the public and public officials. This role was more recently called research or “policy R&D”. A third role is to advocate for competition and markets both domestically and internationally. As a practical matter, the provision of economic advice to the FTC and to the legal staff has required that the economists wear “two hats,” helping the legal staff investigate cases and provide evidence to support law enforcement cases while also providing advice to the legal bureaus and to the Commission on which cases to pursue (thus providing “a second set of eyes” to evaluate cases). There is sometimes a tension in those functions because building a case is not the same as evaluating a case. Economists and the Bureau of Economics have provided such services to the FTC for over 100 years proving that a sub-organization can survive while playing roles that sometimes conflict. Such a life is not, however, always easy or fun.

Until recently, motivation has been considered to be an individual phenomenon. Motivational theorists have accordingly conceptualised key constructs in individualistic terms and emphasised the individual origins and nature of motivation, although they have also long recognised that contextual or social factors have a significant influence on these individual processes. Recently this conceptualisation has been questioned as theorists have suggested, after Vygotsky, that motivation, like learning and thinking, might be social in nature. This idea was first suggested by Sivan (1986) more than twenty years ago but it received a major impetus with the publication of an article by Hickey (1997) eleven years later. Since that time interest in the social nature of motivation has grown as a small number of book chapters and journal articles have been published and conference papers have been presented on the topic. Although some motivational theorists remain sceptical (e.g. Winne, 2004) of this theoretical development, the inclusion of a section on sociocultural approaches to motivation in Perry, Turner, and Meyer's (2006) chapter on classrooms as contexts for motivating learning in the 2nd edition of the Handbook of Educational Psychology suggests that this perspective is being seriously considered by motivational researchers. Similarly, the inclusion of a chapter (Walker, in press-b) on the sociocultural approach to motivation in the 3rd edition of the International Encyclopedia of Education indicates that this approach has achieved some recognition.

The chapter presents a theoretical framework that deals with the basic question of how networks and industries coevolve. We draw upon the structural and relational perspectives of networks to theorize about changes occurring in interfirm networks over time and the coevolutionary linkage of these changes to the industry life cycle. We further extend the widely accepted industry life cycle model by claiming that industry-specific evolutionary patterns impact the structure of the network’s relations, which in turn lead to diversification in the sources of innovation and to variation in the patterns of industrial evolution.

Entrepreneurship education has been largely treated as a pedagogical “black box.” Despite the emergence of popular entrepreneurship models such as business planning, the lean startup, or business model canvas, neither theoretical nor pedagogical foundations are typically evident. This limits the accumulation of useful evidence that could inform better teaching practices. In this chapter, we develop a set of conceptual models anchored in learning theory regarding how entrepreneurship education should be taught to students. These conceptual models are built on the techniques of entrepreneurship pedagogy such as experiential education. They are developed for three groups of students: students without any entrepreneurship experience, students with previous entrepreneurship experience, and students who are currently running their start-ups. A set of potential variables that could be used for course evaluation purposes is also included. The proposed models meet the needs of students with different levels of entrepreneurship experience. Theoretically, we demonstrate that entrepreneurship students should not be treated as a homogeneous group, as they have different levels of startup experience and different educational needs. Lecturers of entrepreneurship programs could choose the suitable model proposed in this chapter in teaching based on the characteristics of their students. The chapter provides novel insights with regard to how entrepreneurship programs should be designed for students with different levels of entrepreneurship experience.

In this chapter, we will look at how the indirect approach can enable us to find a way to learn about young people's lives. The setting for this chapter is informal youth work, reminding us of the value of a wide range of practices with young people, and the findings are equally relevant to formal and informal education as guiding principles for good practice. We will look at the skillful interactions practitioners establish with young people and how they can be developed and promoted. Reflective practice for practitioners is identified as beneficial in adding the value of young people's voice, whilst building relationships. The nature of young people's participation and power is argued to benefit from a co-constructed and socio-cultural understanding; majoring on the importance of context, indirect method and equality literacy framework. We will suggest how the indirect approach can improve young people's lives in schools and/or youth provision.