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This paper aims to present a low-cost, edge-fed, windmill-shaped, notch-band eliminator, circular monopole antenna which is practically loaded with a complementary split ring resonator (CSRR) in the middle of the radiating conductor and also uses a partial ground to obtain wide-band performance.

To compensate for the reduced value of gain and reflection coefficient because of the full (complete) ground plane at the bottom of the substrate, the antenna is further loaded with a partial ground and a CSRR. The reduction in the length of ground near the feed line improves the impedance bandwidth, and introduced CSRR results in improved gain with an additional resonance spike. This results in a peak gain 3.895dBi at the designed frequency 2.45 GHz. The extending of three arms in the circular patch not only led to an increase of peak gain by 4.044dBi but also eliminated the notch band and improved the fractional bandwidth 1.65–2.92 GHz.

The work reports a –10dB bandwidth from 1.63 GHz to 2.91 GHz, which covers traditional coverage applications and new specific uses applications such as narrow LTE bands for future internet of things (NB-IoT) machine-to-machine communications 1.8/1.9/2.1/2.3/2.5/2.6 GHz, industry, automation and business-critical cases (2.1/2.3/2.6 GHz), industrial, society and medical applications such as Wi-MAX (3.5 GHz), Wi-Fi3 (2.45 GHz), GSM (1.9 GHz), public safety band, Bluetooth (2.40–2.485 GHz), Zigbee (2.40–2.48Ghz), industrial scientific medical (ISM) band (2.4–2.5 GHz), WCDMA (1.9, 2.1 GHz), 3 G (2.1 GHz), 4 G LTE (2.1–2.5 GHz) and other personal communication services applications. The estimated RLC electrical equivalent circuit is also presented at the end.

Because of full coverage of Bluetooth, Zigbee, WiFi3 and ISM band, the proposed fabricated antenna is suitable for low power, low data rate and wireless/wired short-range IoT-enabled medical applications.

The antenna is fabricated on a piece (66.4 mm × 66.4 mm × 1.6 mm) of low-cost low profile FR-4 epoxy substrate (0.54 λ_g × 0.54 λ_g) with a dielectric constant of 4.4, a loss tangent of 0.02 and a thickness of 1.6 mm. The antenna reflection coefficient, impedance and VSWR are tested on the Keysight technology (N9917A) vector network analyzer, and the radiation pattern is measured in an anechoic chamber.

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 compact low-cost antenna structure is proposed to augment the impedance-bandwidth in mm-wave range. Beside it, the paper also aimed to enhance high gain for n260 and n261-bands, suitable for futuristic communication systems.

Design consists of radiating patch and a partial ground plane with semi-circle arc for smooth flow of current. The lower corners of patch are gradually clipped away to make the patch nearly elliptical. Further, two tilted slots at an angle α = 15° are etched at the edges of the patch to augment bandwidth for mm-wave range. These slots divert the periphery current of semi elliptical patch towards center portion of antenna which ensures the participation in radiation of central portion of patch. The upper corners are also clipped away to limit the copper losses and smoothly flow of current. The proposed antenna is designed using HFSS and it is structured on inexpensive FR4 substrate of size 27.5 × 20 mm².

It supports enormous −10 dB bandwidth of 5.86–40GHz (148.89%) even though use of high loss-tangent material and high gain for 28 GHz (27.50–28.35 GHz) n261–band and 37 GHz (37–38.6 GHz) and 39 GHz (38.6–40GHz) n260–bands with a peak-gain of 8.76 dBi, 10.8 dBi and 9.92 dBi, respectively.

The proposed methodology of design is very useful to enhance impedance bandwidth to cover all C–, X–, Ku–, K– and Ka–band even though use of low cost material with high loss tangent. In recent literature, the designs were implemented with a costly material and having very low loss tangent and covers partial suggest bands.

This study aims to propose a door detection method based on the door properties in both depth and gray-level images. It can further help blind people (or mobile robots) find the doorway to their destination.

The proposed method uses the hierarchical point–line region principle with majority vote to encode the surface features pixel by pixel, and then dominant scene entities line by line, and finally the prioritized scene entities in the center, left and right of the observed scene.

This approach is very robust for noise and random misclassification in pixel, line and region levels and provides sufficient information for the pathway in the front and on the left and right of a scene. The proposed robot vision-assist system can be worn by visually impaired people or mounted on mobile robots. It provides more complete information about the surrounding environment to guide safely and effectively the user to the destination.

In this study, the proposed robot vision scheme provides detailed configurations of the environment encountered in daily life, including stairs (up and down), curbs/steps (up and down), obstacles, overheads, potholes/gutters, hazards and accessible ground. All these scene entities detected in the environment provide the blind people (or mobile robots) more complete information for better decision-making of their own. This paper also proposes, especially, a door detection method based on the door’s features in both depth and gray-level images. It can further help blind people find the doorway to their destination in an unfamiliar environment.

The purpose of this paper is to present a new dual-band printed monopole antenna with a partial ground with two notched bands based on electromagnetic band gap (EBG) structures. A new type of EBG antenna with radiation patterns and antenna gains over the operating bands has been developed.

The proposed antenna consists of a pair of EBG structures using a transmission line model. The proposed antenna is designed on an FR4 substrate with a thickness of 1 mm and permittivity (e_r) = 4.3.

The measured results show good dual-band operations with −10 dB impedance bandwidths of 9.1 and 36.2 per cent centered at 2.45 and 6.364 GHz, respectively, which covers the wireless local area network (WLAN) operating bands.

A new type of EBG antenna with radiation patterns and antenna gains over the operating bands has been developed.

Self-service technologies (SST) have become more and more pervasive in retail to facilitate autonomous checkout. In this context, customers play an active role and, as such, can be considered as “partial employees.” Partial employees have to perform a wide range of tasks, get rewarded for their work and need to understand the terms of the exchange, all without being subject to a formalized contract. In this research, the authors suggest that partial employees go through a process of organizational socialization that allows them to define the psychological contract they hold with the organization.

In order to investigate the psychological contracts of partial employees, 324 Canadian customers using SST completed an online questionnaire, in which their SST use, psychological contract fulfillment and organizational socialization were measured.

Descriptive analyses highlight that customers as partial employees build a psychological contract with their most frequent retailer, as they perceive not only retailer inducements but also their own contributions. Multiple linear regressions suggest that organizational socialization favors psychological contract fulfillment, but that specific dimensions of organizational socialization are important for employer inducements vs. employee contributions. Moreover, results suggest that the frequency of use of SST as well as the patronage positively predicts psychological contract fulfillment.

This research investigates a specific situation of unconventional employment – that of customers as partial employees with organizations. It contributes to the literature on the psychological contract by broadening its application to new relations and to the literature on customer management by reemphasizing the relevance of the psychological contract in this domain.

This research has the potential to contribute to the understanding of the sustainable ground handling operations framework. Ramp operations as the main system of ground handling include critical services for aircraft/airlines. The purpose of this study is to identify the risk factors in ramp operations for all related stakeholders’ awareness to enhance flight safety. Classifying risk factors, the four main performance fields under risk taxonomy is determined. Thus, managers may allocate resources effectively to handle related threats for corporate sustainability.

New taxonomy with human performance value indicators, which sources from the environment is developed. New developed taxonomy is entitled as “environmental value approach,” which represents environmental value-based approach. The developed new risk factors taxonomy is divided into groups such as ramp personnel, organizational, sustainability-based risk factors: triple view and ergonomics obtained from an extensive literature review and experts’ opinions in the field of human performance.

The findings of this research show that managers need a risk management-oriented approach to manage the human factor affecting performance and sustainability. The newly developed taxonomy offers not only identifying the sources of unsafe operational risk factors but also using as a decision-support tool to manage risks for achieving their sustainability goals. When managerial decisions are made according to risk taxonomy and managing these risks, then corporate performance and individual performance may improve.

The new taxonomy presents the performance-based management of the human factor with a holistic and systematic risk management-based approach. There is no risk taxonomy study designed considering ramp operations and sustainability-based human factor performance.

The purpose of this paper is to evaluate the co-seismic and post-seismic behaviors of an existed soil-foundation system in an actual alternately layered sand/silt ground including pore water pressure, acceleration response, and displacement et al. during and after earthquake.

The evaluation is performed by finite element method and the simulation is performed using an effective stress-based 2D/3D soil-water coupling program DBLEAVES. The calculation is carried out through static-dynamic-static three steps. The soil behavior is described by a new rotational kinematic hardening elasto-plastic cyclic mobility constitutive model, while the footing and foundation are modeled as elastic rigid elements.

The shallow (short-pile type) foundation has a better capacity of resisting ground liquefaction but large differential settlement occurred. Moreover, most part of the differential settlement occurred during earthquake motion. Attention should be paid not only to the liquefaction behavior of the ground during the earthquake motion, but also the long-term settlement after earthquake should be given serious consideration.

The co-seismic and post-seismic behavior of a complex ground which contains sand and silt layers, especially long-term settlement over a period of several weeks or even years after the earthquake, has been clarified sufficiently. In some critical condition, even if the seismic resistance is satisfied with the design code for building, detailed calculation may reveal the risk of under estimation of differential settlement that may give rise to serious problems.

Earth retaining and structural foundation works are commonly built from rolled steel piling products which are designed and manufactured to cover a wide range of structural applications. Product data must not only provide design and application information, but also steel corrosion rates in the full range of service environments and, in this context, the corrosion of steel piling has been extensively studied both from examinations of actual structures and from more fundamental studies. Corrosion researches cover both corrosion‐protected and bare steel piling and, in order to appreciate fully the value of these researches, a simplified but adequate explanation of steel corrosion is given.

Compact and wideband antennas are the need of modern wireless systems that preferably work with compact, low-profile and easy-to-install devices that provide a wider coverage of operating frequencies. The purpose of this paper is to propose a novel compact and ultrawideband (UWB) microstrip patch antenna intended for high frequency wireless applications.

A square microstrip patch antenna was initially modeled on finite element method-based electromagnetic simulation tool high frequency structure simulator. It was then loaded with a rectangular slit and Koch snowflake-shaped fractal notches for bandwidth enhancement. The fabricated prototype was tested by using vector network analyzer from Agilent Technologies, N5247A, Santa Clara, California, United States (US).

The designed Koch fractal patch antenna is highly compact with dimensions of 10 × 10 mm only and possesses UWB characteristics with multiple resonances in the operating band. The −10 dB measured impedance bandwidth was observed to be approximately 13.65 GHz in the frequency range (23.20–36.85 GHz).

Owing to its simple and compact structure, positive and substantial gain values, high radiation efficiency and stable radiation patterns throughout the frequency band of interest, the proposed antenna is a suitable candidate for high frequency wireless applications in the K (18–27 GHz) and Ka (26.5–40 GHz) microwave bands.