scholarly journals Response of personal exposimeters for exposure assessment in the GSM900 downlink band

2015 ◽  
Vol 34 (4) ◽  
pp. 1076-1084 ◽  
Author(s):  
Arno Thielens ◽  
Sam Agneessens ◽  
Günter Vermeeren ◽  
Leen Verloock ◽  
Hendrik Rogier ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Numerical Simulations ◽  
Electric Fields ◽  
Mobile Communications ◽  
Design Methodology ◽  
Human Subjects ◽  
Far Field ◽  
Percent Confidence Interval ◽  
Global System ◽  
Content Type

Purpose – The purpose of this paper is to numerically determine the distribution of electric fields registered by a personal exposimeter (PEM) used for the Global System for Mobile Communications (GSM) around 900 MHz (GSM900) downlink (DL) band and compare these with calibration measurements of PEMs worn by real human subjects. Design/methodology/approach – Numerical simulations using the Virtual Family Male (VFM) are carried out at 950 MHz in order to determine the electric fields surrounding the phantom in realistic, far-field environments. These electric fields can be used to determine the distribution of a PEM’s response when worn by the VFM. Simultaneously, calibration measurements in an anechoic chamber are carried out using a real PEM worn by two different subjects, in order to determine the PEM’s response experimentally. Findings – Both the numerical simulations and the measurements show that a PEM will on average underestimate the incident electric fields in the GSM900 DL band and that the variation (expressed in terms of the 95 percent confidence interval and the interquartile distance) on its response is relatively large: a 95 percent confidence interval of 22 dB and an interquartile distance of 7.3 dB are found in a realistic environment using numerical simulations, while the calibration measurements show interquartile distances up to 12 dB. In terms of variation there is an excellent agreement between simulations and measurements. Originality/value – This paper proves that numerical simulations may be used as a replacement for the more time- and work-consuming calibration measurements if the variation of a PEM’s response is studied.

Dynamic ease evaluation for 3D garment design

2018 ◽  
Vol 22 (2) ◽  
pp. 209-222
Author(s):  
Fangfang Zhang ◽  
Trevor John Little
Keyword(s):  
Human Body ◽  
Design Methodology ◽  
Human Subjects ◽  
Essential Element ◽  
The Body ◽  
Upper Arm ◽  
Core Element ◽  
Content Type ◽  
Comfort Evaluation ◽  
Garment Design

Purpose 3D garment design technology is developing rapidly thereby creating a need for different approaches to developing the patterns. The purpose of this paper is to evaluate the 3D dynamic ease distribution for a 3D garment design. Design/methodology/approach Standard garments were created from Size 2 to Size 14 for ten human subjects. Landmarks location on both human body and the standard garment under dynamic postures are recorded, and he fit and comfort evaluation of the standard garment were collected from the ten human subjects. Finally, these data were used to evaluate the 3D dynamic ease distribution for a 3D garment design. Findings 3D dynamic ease evaluation is challenging and the findings showed that the upper-arm design is a core element of the whole 3D garment design. The upper arm is not only a connecting part for both front and back pieces of the garment, but is also the main active part of the body, so it is the essential element to affect the comfort and fit of the garment under dynamic postures. Originality/value This research provides a novel 3D ease evaluation by analyzing the landmarks location of both human body and standard garment, and fit and comfort evaluation of the standard garment, which are all carried under dynamic postures.

Dielectric breakdown simulations of an OLTC in a transformer

2014 ◽  
Vol 33 (4) ◽  
pp. 1145-1160 ◽  
Author(s):  
Maximilian Wiesmüller ◽  
Beate Glaser ◽  
Franz Fuchs ◽  
Oliver Sterz
Keyword(s):  
Electric Fields ◽  
Design Methodology ◽  
Dielectric Breakdown ◽  
Power Transformer ◽  
Test Procedures ◽  
Content Type ◽  
Element Simulation ◽  
Standard Design ◽  
Tap Changer ◽  
Load Tap Changer

Purpose – The purpose of this paper is to report on the simulation of an on-load tap-changer (OLTC) in a power transformer. During design and test of the electrical insulation the influence of the environment on the OLTC is normally neglected. The authors investigate how large these influences are. Design/methodology/approach – The environment of the OLTC is taken into account by modeling tap leads in detail as well as transformer windings. The electric fields are computed and resulting breakdown voltages are estimated by using the streamer criterion. The results are compared to the ones of an OLTC without transformer and leads. Findings – For the investigated typical example the influence of the transformer and the tap leads on the internal OLTC insulation is small enough to neglect them during design optimization and test procedures. Originality/value – New is the execution of a finite element simulation and breakdown evaluation of such a complex geometric structure as the complete system consisting of OLTC combined with tap leads and windings. Furthermore, standard design and test procedures used by OLTC manufacturers are justified.

A new approximation for the risk premium with large risks

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Richard Watt ◽  
Philip Gunby
Keyword(s):  
Numerical Simulations ◽  
Risk Premium ◽  
Design Methodology ◽  
Content Type ◽  
True Value ◽  
Risk Neutral ◽  
Risk Neutral Probabilities

PurposeThe Arrow–Pratt approximation to the risk premium is only valid for small risks. In this paper we consider a second approximation, based on risk-neutral probabilities and which requires no greater information than the Arrow–Pratt approximation, that works well for both small and large risks.Design/methodology/approachThe paper is theoretical in nature, although it also provides illustrative numerical simulations.FindingsThe new approximation proposed here appears to be significantly superior to Arrow–Pratt for approximating the true value of the risk premium when the risk is large. It may also approximate better even for relatively small risks.Originality/valueAs far as we are aware, there are no other known approximations for the risk premium when the risk involved is large.

Bounds for increasing multi-state linear k-within-(r,s)-of-(m,n):F lattice system

2018 ◽  
Vol 35 (5) ◽  
pp. 1142-1156
Author(s):  
Taha Radwan
Keyword(s):  
Complex System ◽  
Mobile Communications ◽  
System Reliability ◽  
Design Methodology ◽  
Lattice System ◽  
Content Type ◽  
Numerical Examples ◽  
Oil Pipeline ◽  
Special Cases ◽  
Practical Implications

Purpose A multi-state linear k-within-(r, s)-of-(m, n): F lattice system consists of m×n components arranged in m rows and n columns. The possible states of the system and its components are: 0, 1, 2, …, H. According to k values, the system can be categorized into three special cases: decreasing, increasing and constant. The system reliability of decreasing and constant cases exists. The purpose of this paper is to evaluate the system reliability in increasing case with i.i.d components, where there is no any algorithm for evaluating the system reliability in this case. Design/methodology/approach The Boole-Bonferroni bounds were applied for evaluating the reliability of many systems. In this paper, the author reformulated the second-order Boole-Bonferroni bounds to be suitable for the evaluation of the multi-state system reliability. And the author applied these bounds for deriving the lower bound and upper bound of increasing multi-state linear k-within-(r, s)-of-(m, n): F lattice system. Findings An illustrated example of the proposed bounds and many numerical examples are given. The author tested these examples and concluded the cases that make the new bounds are sharper. Practical implications In this paper, the author considered an important and complex system, the multi-state linear k-within-(r, s)-of-(m, n): F lattice system; it is a model for many applications, for example, telecommunication, radar detection, oil pipeline, mobile communications, inspection procedures and series of microwave towers systems. Originality/value This paper suggests a method for the computation of the bounds of increasing multi-state linear k-within-(r,s)-of-(m,n): F lattice system. Furthermore, the author concluded that the cases that make these bounds are sharper.

Tuning into rebellious matter: affective literacies as more-than-human sonic bodies

2020 ◽  
Vol 19 (4) ◽  
pp. 417-432
Author(s):  
Bessie Patricia Dernikos
Keyword(s):  
Design Methodology ◽  
First Graders ◽  
Human Subjects ◽  
Ways Of Knowing ◽  
The Political ◽  
White Supremacist ◽  
Content Type ◽  
The Social ◽  
Educational Spaces ◽  
Literacy Educators

Purpose The purpose of this paper is to explore the sonic vibrations, infectious rhythms and alternative frequencies that are often unheard and overlooked within mainstream educational spaces, that is, perceptually coded out of legibility by those who read/see/hear the world through “whiteness.” Design/methodology/approach “Plugging into” (Jackson and Mazzei, 2012) posthuman theories of affect (Deleuze and Guattari, 1987; Henriques, 2010) and assemblage (Weheliye, 2014), the author argues that “literate bodies,” along with all forms of matter, continually vibrate, move, swell and rebel (Deleuze, 1990), creating momentum that is often difficult not to get tangled up in. Findings This paper maps out how a specific sociohistorical concept of sound works to affectively orient bodies and impact student becomings, namely, by producing students as un/successful readers and in/human subjects. At the same time, the author attends to the subtle ways by which first graders rebelliously move (d) with alternative sonic frequencies to resist/disrupt mandated literacy curricula and white, patriarchal ways of knowing, being and doing. Originality/value This paper highlights the political nature of sound and how, within mainstream educational spaces, certain sonic frequencies become coded out of white supremacist models for knowledge transmission, which re/produce racialized (gendered, classist, etc.) habits and practices of listening/hearing. Literacy educators are invited to “(re)hear” the social in more just ways (James, 2020) by sensing the affects and effects of more-than-human “sonic bodies” (Henriques, 2011), which redirect us to alternative rhythms, rationalities, habits and practices that challenge normative conceptions of what counts as literacy and who counts as successfully literate.

High gain switched beam Yagi-Uda antenna for millimeter wave communications

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Pramod Kumar Aylapogu ◽  
Madhu Sudan Donga ◽  
Venkatachari D. ◽  
RamaDevi B.
Keyword(s):  
Millimeter Wave ◽  
Mobile Communications ◽  
Design Methodology ◽  
High Gain ◽  
Wireless Devices ◽  
High Efficacy ◽  
Content Type ◽  
Feed Line ◽  
5G Mobile Communications ◽  
Millimeter Wave Communications

Purpose The suggested antenna has a switched mechanism among the successive elements of the radiating patch. The purpose of this paper is to develop high gain and less interference at higher frequencies. Design/methodology/approach The design geometry of the suggested high gain switched beam Yagi-Uda antennas. The constructed antenna has been developed with Rogers Substrate, relative permittivity (εr) of 4.4, tangent of loss 0.0009 and with height of 1.6 mm. The proposed antenna has an input impedance of 50, and it is connected to input feed line with 2 mm. Findings In forthcoming life, the antennas play key role in all the wireless devices, because these devices perform with high gain and high efficacy. Originality/value The pivotal principle of this paper is to accomplish the gain as high, high directivity and interference is low at higher frequencies. Therefore, it is more applicable to 5G mobile communications and millimeter wave communications.

Reconfiguration method of tensegrity units using infinitesimal mechanisms

2019 ◽  
Vol 36 (6) ◽  
pp. 1934-1949 ◽  
Author(s):  
Andrés González ◽  
Ani Luo ◽  
Dongyan Shi
Keyword(s):  
Numerical Simulations ◽  
Equilibrium Problem ◽  
Design Methodology ◽  
Main Idea ◽  
Small Displacement ◽  
Force Density ◽  
Stable Configuration ◽  
String Length ◽  
Content Type ◽  
Tensegrity Structures

Purpose This paper aims to present a reconfiguration strategy for actuated tensegrity structures. The main idea is to use the infinitesimal mechanisms of the structure to generate a path along which the tensegrity can change its shape while maintaining the equilibrium. Design/methodology/approach Combining the force density method with a marching procedure, the solution to the equilibrium problem is given by a set of differential equations. Beginning from an initial stable position, the algorithm calculates a small displacement until a new stable configuration is reached, and recurrently repeats the process during a given interval of time. Findings By means of three numerical simulations and their respective experimental example, the efficacy of this algorithm for reconfiguring the well-known three-bar tensegrity prism along different directions is shown. The proposed method shows efficiency only for small changes of string length. Further work should consider the application of this method to more complex tensegrity structures. Originality/value The advantage of this reconfiguration method is its simplicity for finding new stable positions for tensegrity structures, and the fact that it doesn’t need the information of the material of the structure for the computations.

Symmetrically scaled coexisting behaviors in two types of simple jerk circuits

Circuit World ◽  
2020 ◽  
Vol 47 (1) ◽  
pp. 61-70
Author(s):  
Mengjie Hua ◽  
Shuo Yang ◽  
Quan Xu ◽  
Mo Chen ◽  
Huagan Wu ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Numerical Simulations ◽  
Design Methodology ◽  
Experimental Measurements ◽  
Equilibrium Stability ◽  
Feedback Channel ◽  
Engineering Applications ◽  
Content Type ◽  
Resistive Feedback ◽  
Attraction Basins

Purpose The purpose of this paper is to develop two types of simple jerk circuits and to carry out their dynamical analyses using a unified mathematical model. Design/methodology/approach Two types of simple jerk circuits only involve a nonlinear resistive feedback channel composited by a nonlinear device and an inverter. The nonlinear device is implemented through parallelly connecting two diode-switch-based series branches. According to the classifications of switch states and circuit types, a unified mathematical model is established for these two types of simple jerk circuits, and the origin symmetry and scale proportionality along with the origin equilibrium stability are thereby discussed. The coexisting bifurcation behaviors in the two types of simple jerk systems are revealed by bifurcation plots, and the origin symmetry and scale proportionality are effectively demonstrated by phase plots and attraction basins. Moreover, hardware experimental measurements are performed, from which the captured results well validate the numerical simulations. Findings Two types of simple jerk circuits are unified through parallelly connecting two diode-switch-based series branches and a unified mathematical model with six kinds of nonlinearities is established. Especially, the origin symmetry and scale proportionality for the two types of simple jerk systems are discussed quantitatively. These jerk circuits are all simple and inexpensive, easy to be physically implemented, which are helpful to explore chaos-based engineering applications. Originality/value Unlike previous works, the significant values are that through unifying these two types of simple jerk systems, a unified mathematical model with six kinds of nonlinearities is established, upon which symmetrically scaled coexisting behaviors are numerically disclosed and experimentally demonstrated.

Sampling-based estimation method for parameter estimation in big data business era

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Abdul Alim ◽  
Diwakar Shukla
Keyword(s):  
Machine Learning ◽  
Decision Making ◽  
Big Data ◽  
Confidence Interval ◽  
Design Methodology ◽  
Data Centers ◽  
Alert System ◽  
Present Sample ◽  
Content Type ◽  
Multiple Data Sets

PurposeThis paper aims to present sample-based estimation methodologies to compute the confidence interval for the mean size of the content of material communicated on the digital social media platform in presence of volume, velocity and variety. Confidence interval acts as a tool of machine learning and managerial decision-making for coping up big data.Design/methodology/approachRandom sample-based sampling design methodology is adapted and mean square error is computed on the data set. Confidence intervals are calculated using the simulation over multiple data sets. The smallest length confidence interval is the selection approach for the most efficient in the scenario of big data.FindingsResultants of computations herein help to forecast the future need of web-space at data-centers for anticipation, efficient management, developing a machine learning algorithm for predicting better quality of service to users. Finding supports to develop control limits as an alert system for better use of resources (memory space) at data centers. Suggested methodologies are efficient enough for future prediction in big data setup.Practical implicationsIn IT sector, the startup with the establishment of data centers is the current trend of business. Findings herein may help to develop a forecasting system and alert system for optimal decision-making in the enhancement and share of the business.Originality/valueThe contribution is an original piece of thought, idea and analysis, deriving motivation from references appended.

scholarly journals Modeling of mobile channels using TIMS in IT education

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Martin Rakús ◽  
Peter Farkaš ◽  
Tomáš Páleník
Keyword(s):  
Information Technology ◽  
Undergraduate Students ◽  
Mobile Communications ◽  
Design Methodology ◽  
Line Of Sight ◽  
Content Type ◽  
Hands On ◽  
It Education ◽  
Mobile Channels ◽  
Link Information

PurposeThe purpose of this paper is to directly link information technology (IT) education with real-world phenomena.Design/methodology/approachThe selected objectives are achieved by modeling line of sight (LOS) and nonline of sight (NLOS) mobile channels using corresponding distributions. Within the described experiments, students verify whether modeled generators generate random variables accordingly to the selected distribution. The results of observations are directly compared with theoretical expectations. The methodology was evaluated by students via questionnaires.FindingsThe results show that the proposed methodology can help graduate or undergraduate students better comprehend lectured material from mobile communications or mathematical statistics.Originality/valueThe hands on experience using the EMONA system make the approach original.

Sign in / Sign up

Export Citation Format

Share Document