scholarly journals A Multiband Diversity Antenna System for Compact Mobile/Wireless Devices: Modeling and Performance Evaluation

2008 ◽  
Vol 2008 ◽  
pp. 1-7 ◽  
Author(s):  
M. Karaboikis ◽  
V. Papamichael ◽  
C. Soras ◽  
V. Makios
Keyword(s):  
Local Area ◽  
Antenna System ◽  
Maximal Ratio Combining ◽  
Method Of Moment ◽  
Wireless Devices ◽  
Worst Case ◽  
Operational Characteristics ◽  
Monopole Antennas ◽  
And Performance ◽  
Diversity Antenna

A novel compact multiband diversity antenna system appropriate for integration onto space-limited devices is presented. It comprises three pairs of printed fractal Minkowski and Koch monopole antennas which resonate in the 1.67–2, 2.3–2.56 and 4.55–5.55 GHz bands, respectively, supporting thus a large variety of wireless technologies for mobile and wireless local area networks (WLANs) applications. The operational characteristics of the antenna system were extracted by simulation using a method-of-moment- (MoM-) based electromagnetic field solver. The diversity performance in a uniform multipath environment under the maximal-ratio combining (MRC) scheme is also evaluated for the two extreme modes of operation, that is, when all three antenna pairs operate simultaneously (worst case) and when only one pair is active while the others being open-circuited (best case). The calculated effective diversity gain (EDG) for the worst/best case is 5.8/6.4, 5.8/7.2 and 7.1/7.5 dB for the 1.8, 2.4 and 5.2 GHz frequencies, respectively.

A printed multiband MIMO antenna with decoupling element

2019 ◽  
Vol 11 (4) ◽  
pp. 413-419 ◽  
Author(s):  
Ziyu Xu ◽  
Qisheng Zhang ◽  
Linyan Guo
Keyword(s):  
Mutual Coupling ◽  
Surface Current ◽  
Antenna System ◽  
Antenna Element ◽  
Coupling Mechanism ◽  
Mimo Antenna ◽  
Resonant Modes ◽  
Monopole Antennas ◽  
Input Multiple Output ◽  
Ground Plate

AbstractA printed multiband Multi-Input Multiple-Output (MIMO) antenna is proposed in this paper. This MIMO antenna system comprises two symmetric printed monopole antennas. Each antenna element consists of multiple bend lines, producing four resonant modes and covering the GSM900, PCS, LTE2300, and 5G bands. Simulated and measured results prove that the proposed MIMO antenna can be applied to traditional 2G, 3G, 4G, and present 5G mobile communication. By etching four inverted L-shaped grooves on its ground plate, mutual coupling between the adjacent antenna elements has been suppressed. This makes the |S21| at all four resonant modes is lower than −40 dB. In addition, its low coupling mechanism has been analyzed by surface current distribution. The designed multiband MIMO antenna provides an idea of reference to realize low mutual coupling between antenna elements, which is also realizable in infrared or optical regimes with appropriate designs.

Does corporate governance affect the performance of Islamic banks? New insight into Islamic countries

2020 ◽  
Vol 20 (6) ◽  
pp. 1073-1090 ◽  
Author(s):  
Ejaz Aslam ◽  
Razali Haron
Keyword(s):  
Corporate Governance ◽  
Audit Committee ◽  
Positive Impact ◽  
Islamic Banks ◽  
Governance Mechanism ◽  
Method Of Moment ◽  
Content Type ◽  
Return On Equity ◽  
Islamic Countries ◽  
And Performance

Purpose Corporate governance plays a significant role to overcome agency issues and develop the culture of transparency and openness. In this context, this paper aims to examine how corporate governance mechanisms affect the performance of Islamic banks (IBs). Design/methodology/approach Stepwise, two-step system generalize method of moment estimation technique is used in the analysis in which control variables are added into the model sequentially. This study used data on 129 IBs from 29 Islamic countries (Middle East, South Asia and Southeast Asia) during the period of 2008 to 2017. Findings The findings suggest that the audit committee (AUDC) and Shariah board (SB) have positive impact on the performance of IBs (return on assets and return on equity). However, board size and risk management committee have negative and significant effect on the performance of IBs. CEO duality and non-executive directors have mixed relationship with the performance of IBs. These results support the argument that IBs need to improve their financial performance through appropriate governance mechanism. Research limitations/implications The findings of the study added a new dimension to the governance research that could be a valuable source of knowledge for policymakers and regulators to improve the existing governance mechanism for better performance of IBs. Originality/value The study fills the gap in the literature by addressing the issue of corporate governance on performance of IBs across countries. Agency theory is discussed to explain the relationship between corporate governance mechanism and performance.

scholarly journals Use of simulation model for measurement of MilkRun system performance

2019 ◽  
Vol 9 (1) ◽  
pp. 600-605 ◽  
Author(s):  
Gabriel Fedorko ◽  
Martin Vasil ◽  
Michaela Bartosova
Keyword(s):  
Simulation Model ◽  
Production Systems ◽  
Operational Performance ◽  
Transport Systems ◽  
Indirect Methods ◽  
Operational Characteristics ◽  
Wide Range ◽  
Effective Operation ◽  
And Performance ◽  
Plant Simulation

AbstractIntra-plant transport systems within their operation directly impact on the performance of production systems. For their effective operation, it is, therefore, necessary to realize evaluation of operational performance and effectivity. For the realization of this type of evaluation, in addition to a wide range of sensors that can be difficult for installation and operation, we can also use indirect methods that are equally able to provide reliable operational characteristics. Indirect analytical methods are presented above all by the approach which is based on the use of simulation methods. The method of computer simulation provides a wide range of options for the evaluation of efficiency and performance. The paper describes the use of a simulation model created in the program Tecnomatix Plant Simulation for analyzing the supply of production workplaces within the MilkRun system.

Rhombus-Shaped Cross-Slot and Notched Loaded Microstrip Patch Antenna

2020 ◽  
pp. 102-111
Author(s):  
Gaurav Varma ◽  
Rishabh Kumar Baudh
Keyword(s):  
Patch Antenna ◽  
Wireless Local Area Network ◽  
Local Area Network ◽  
Dielectric Material ◽  
Local Area ◽  
Microstrip Patch Antenna ◽  
Area Network ◽  
Method Of Moment ◽  
Microstrip Patch ◽  
Ring Shape

The aim is to design a Rhombus microstrip patch antenna. The antenna operates at FL=1.447 GHz to FH=2.382 GHz frequency for wireless local area network (WLAN). This antenna operates at f=1.914 GHz resonant frequency. In microstrip patch antenna, many types of shapes like circular, triangular, rectangular, square, ring shape, etc. are used, but in this design a rectangular shape is used. In proposed antenna, the accuracy and efficiency are increased. Integral equation three-dimensional (3D) software (IE3D) is used for the optimize of the rhombus cross-slotted antenna design. The IE3D uses a full wave method of moment simulator. This antenna fabricated on FR4 glass epoxy double-sided copper dielectric material with relative permittivity of ∈ =4.4, thickness h= 1.60mm, and loss tangent is 0.013.

Initial Price Strategies of Polish Micro and Small Enterprises

2017 ◽  
pp. 126-143
Author(s):  
Mariusz Maciejczak ◽  
Adrian Słodki
Keyword(s):  
Game Theory ◽  
Point Of View ◽  
Medium Size ◽  
Small Enterprises ◽  
Small Companies ◽  
Case Scenario ◽  
Worst Case ◽  
The Game Theory ◽  
Real Market ◽  
And Performance

The sector of micro, small and medium size enterprises is important for any economy. It is important also for Poland. Analyzing the industrial organization of this sector it was confirmed that the owners and managers of such companies are applying strategies, which are rational from their point of view, but not from the perspective of real market conditions. It is argued therefore that the game theory is for them a solution in enhancing competences and performance of their organizations. Based on randomized sample of Polish micro and small companies the paper aimed to find out if the managers apply the game theory rationales when choosing price strategy when enter the market. It was confirmed that they do not and that they don't play Nash equilibrium in the strategic interaction when it comes to the price level. There was applied maxmin strategy, which maximises the worst - case scenario from the game. Thus there is a real chance that if entrepreneurs would analyze the situation with respect of game theory, their strategies would be more accurate and provide better outcomes.

scholarly journals SLFAT: Client-Side Evil Twin Detection Approach Based on Arrival Time of Special Length Frames

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Qian Lu ◽  
Haipeng Qu ◽  
Yuzhan Ouyang ◽  
Jiahui Zhang
Keyword(s):  
Arrival Time ◽  
Access Point ◽  
Local Area ◽  
Security Threats ◽  
Wireless Devices ◽  
High Detection Rate ◽  
Malicious Adversary ◽  
Detection Approach ◽  
Client Side ◽  
Very High

In general, the IEEE 802.11 network identifiers used by wireless access points (APs) can be easily spoofed. Accordingly, a malicious adversary is able to clone the identity information of a legitimate AP (LAP) to launch evil twin attacks (ETAs). The evil twin is a class of rogue access point (RAP) that masquerades as a LAP and allures Wi-Fi victims’ traffic. It enables an attacker with little effort and expenditure to eavesdrop or manipulate wireless communications. Due to the characteristics of strong concealment, high confusion, great harmfulness, and easy implementation, the ETA has become one of the most severe security threats in Wireless Local Area Networks (WLANs). Here, we propose a novel client-side approach, Speical Length Frames Arrival Time (SLFAT), to detect the ETA, which utilizes the same gateway as the LAP. By monitoring the traffic emitted by target APs at a detection node, SLFAT extracts the arrival time of the special frames with the same length to determine the evil twin’s forwarding behavior. SLFAT is passive, lightweight, efficient, hard to be escaped. It allows users to independently detect ETA on ordinary wireless devices. Through implementation and evaluation in our study, SLFAT achieves a very high detection rate in distinguishing evil twins from LAPs.

scholarly journals Power and Area Efficient Clock Stretching and Critical Path Reshaping for Error Resilience

2019 ◽  
Vol 9 (1) ◽  
pp. 5
Author(s):  
Mini Jayakrishnan ◽  
Alan Chang ◽  
Tony Tae-Hyoung Kim
Keyword(s):  
Critical Path ◽  
Error Resilience ◽  
Cost Effective ◽  
Advanced Technology ◽  
Worst Case ◽  
Flip Flop ◽  
Smart Products ◽  
Run Time ◽  
Critical Paths ◽  
And Performance

Energy efficient semiconductor chips are in high demand to cater the needs of today’s smart products. Advanced technology nodes insert high design margins to deal with rising variations at the cost of power, area and performance. Existing run time resilience techniques are not cost effective due to the additional circuits involved. In this paper, we propose a design time resilience technique using a clock stretched flip-flop to redistribute the available slack in the processor pipeline to the critical paths. We use the opportunistic slack to redesign the critical fan in logic using logic reshaping, better than worst case sigma corner libraries and multi-bit flip-flops to achieve power and area savings. Experimental results prove that we can tune the logic and the library to get significant power and area savings of 69% and 15% in the execute pipeline stage of the processor compared to the traditional worst-case design. Whereas, existing run time resilience hardware results in 36% and 2% power and area overhead respectively.

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