scholarly journals On the Design of Conical Antennas for Broadband Impedance Matching Performance

2017 ◽  
Vol 2017 ◽  
pp. 1-13
Author(s):  
Francisco Estêvão Simão Pereira ◽  
Maurício Henrique Costa Dias
Keyword(s):  
Input Impedance ◽  
Impedance Matching ◽  
Closed Form Solution ◽  
Form Solution ◽  
Geometrical Parameters ◽  
Performance Potential ◽  
Biconical Antenna ◽  
Matching Performance ◽  
Design Perspective ◽  
The Impact

In the scope of broadband radiators, the biconical antenna, or its monopole conical counterpart, is long known to be a proper choice. One common form of such radiator, the spherically capped conical antenna (SCCA), has closed-form solution to its input impedance, from which the broadband performance potential is easily verified. Nonetheless, from the design perspective, apart from a few clues inferred from existing solutions, little is found to accurately guide the choice of the main geometrical parameters of the antenna that will enable it to comply with a set of imposed bandwidth requirements. This paper proposes a simple 10-step sequence to derive conical or biconical antenna design charts. These charts provide straightforward information on the geometrical limits within which the required antenna impedance matching broadband performance is achieved. The method is assessed for the SCCA and the open conical antenna (OCA) using theoretical and simulated estimates of the input impedance. A discussion on the impact of the cap and the feed gap is included.

scholarly journals On the impact of antenna diversity in IEEE 802.11b DCF with capture

2004 ◽  
Vol 17 (1) ◽  
pp. 41-52
Author(s):  
Zoran Velkov-Hadzi ◽  
Boris Spasenovski
Keyword(s):  
Closed Form ◽  
Closed Form Solution ◽  
Access Point ◽  
Form Solution ◽  
Capture Probability ◽  
Antenna Diversity ◽  
Ieee 802.11B ◽  
Selection Diversity ◽  
Maximum Selection ◽  
The Impact

In this paper, we examined the influence of capture effect with L-fold antenna diversity at the Access Point over IEEE 802.11b DCF. We obtained an exact closed-form solution for the conditional capture probability in case of ideal selection diversity, and an approximate closed-form solution for the conditional capture probability in case of maximum selection diversity in a Rayleigh-faded channel. Obtained analytical expressions have general significance and can be applied for any other multiple access wireless network. We also analytically evaluated saturation throughput increase of the IEEE 802.11b DCF protocol exposed to capture.

Analysis of Simply-Supported Orthotropic Cylindrical Shells Subject to Lateral Impact Loads

1990 ◽  
Vol 57 (2) ◽  
pp. 376-382 ◽  
Author(s):  
A. P. Christoforou ◽  
S. R. Swanson
Keyword(s):  
Cylindrical Shells ◽  
Closed Form Solution ◽  
Double Fourier Series ◽  
Form Solution ◽  
Lateral Impact ◽  
Simply Supported ◽  
Response Characteristics ◽  
Simple Support ◽  
The Impact ◽  
Approximate Procedure

An analytic solution is given for the problem of simply-supported orthotropic cylindrical shells subject to impact loading. The closed-form solution has not been obtained previously. The analysis is based on an expansion of the loads, displacements, and rotations in a double Fourier series which satisfies the end boundary conditions of simple support. Each expansion is assumed to be separable into a function of time and a function of position. By neglecting in-plane and rotary inertia the problem becomes a second-order ordinary differential equation in time for the Fourier coefficients of the radial deflection. For a given loading impulse the solution can be found by invoking the convolution integral. The results show that for impact by a heavy mass, the solution is equivalent to that obtained by an approximate procedure of neglecting the mass of the shell, which leads to a simple simple-degree-of-freedom analysis. For problems of impact by smaller masses, the higher response frequencies of the cylinder become important. The results show the importance of dynamic effects in the predicted impact duration, peak force, and peak deflection relative to the quasi-static response. The results show that the response amplitude varies linearly with the impact velocity, but the response characteristics depend on the mass of the impactor and the mass and stiffness of the cylinder.

A closed-form solution to eye-to-hand calibration towards visual grasping

2014 ◽  
Vol 41 (6) ◽  
pp. 567-574 ◽  
Author(s):  
Hui Pan ◽  
Na Li Wang ◽  
Yin Shi Qin
Keyword(s):  
Closed Form ◽  
Design Methodology ◽  
Closed Form Solution ◽  
Form Solution ◽  
Content Type ◽  
The Impact ◽  
Calibration Plane

Purpose – The purpose of this paper is to propose a method that calibrates the hand-eye relationship for eye-to-hand configuration and afterwards a rectification to improve the accuracy of general calibration. Design/methodology/approach – The hand-eye calibration of eye-to-hand configuration is summarized as a equation AX = XB which is the same as in eye-in-hand calibration. A closed-form solution is derived. To abate the impact of noise, a rectification is conducted after the general calibration. Findings – Simulation and actual experiments confirm that the accuracy of calibration is obviously improved. Originality/value – Only a calibration plane is required for the hand-eye calibration. Taking the impact of noise into account, a rectification is carried out after the general calibration and, as a result, that the accuracy is obviously improved. The method can be applied in many actual applications.

scholarly journals Optimal control of an inventory system under whole sale price changes

2019 ◽  
Author(s):  
Ata Allah Taleizadeh ◽  
Hamidreza Zarei ◽  
Shib Sankar Sana
Keyword(s):  
Closed Form Solution ◽  
Form Solution ◽  
Price Changes ◽  
Total Saving ◽  
Ordering Policy ◽  
Decision Variables ◽  
Optimal Ordering Policy ◽  
Optimal Ordering ◽  
The Impact ◽  
Special Order

Nowadays business owners use lots of incentive schemes to make customers buy more products. In this paper optimal ordering policy for customers is obtained when the manufacturer increases the purchasing price or temporary decreases it. Offering a special sale from the manufacturer is probabilistic and shortage occurs as partial backlogging. In this paper, the initial level of inventory when the purchasing price changes is not equal to zero. With respect to the assumptions, the amount of special order quantity, the shortage quantity, and the expected total saving from making an special order is optimized for the customer. The optimal amount of decision variables are obtained by maximizing the expected total saving function and a closed-form solution is derived. Several numerical examples are solved and sensitivity analysis is performed to prove the applicability of the proposed model. Finally, the impact of some parameters of the model including the demand, the probability of making a special order, the future prices, and the initial inventory is investigated. Optimal ordering policy for the customers is obtained in cases when an announced price increase occurs and when the prices temporarily decrease.

scholarly journals Bilateral Defaultable Financial Derivatives Pricing and Credit Valuation Adjustment

2019 ◽  
Author(s):  
Tim Xiao
Keyword(s):  
Interest Rates ◽  
Closed Form Solution ◽  
Financial Derivatives ◽  
Form Solution ◽  
Reduced Form ◽  
Derivatives Pricing ◽  
Default Time ◽  
Form Model ◽  
The One ◽  
The Impact

The one-side defaultable financial derivatives valuation problems have been studied extensively, but the valuation of bilateral derivatives with asymmetric credit qualities is still lacking convincing mechanism. This paper presents an analytical model for valuing derivatives subject to default by both counterparties. The default-free interest rates are modeled by the Market Models, while the default time is modeled by the reduced-form model as the first jump of a time-inhomogeneous Poisson process. All quantities modeled are market-observable. The closed-form solution gives us a better understanding of the impact of the credit asymmetry on swap value, credit value adjustment, swap rate and swap spread.

scholarly journals Bilateral Defaultable Financial Derivatives Pricing and Credit Valuation Adjustment

2019 ◽  
Author(s):  
Tim Xiao
Keyword(s):  
Interest Rates ◽  
Closed Form Solution ◽  
Financial Derivatives ◽  
Form Solution ◽  
Reduced Form ◽  
Derivatives Pricing ◽  
Default Time ◽  
Form Model ◽  
The One ◽  
The Impact

The one-side defaultable financial derivatives valuation problems have been studied extensively, but the valuation of bilateral derivatives with asymmetric credit qualities is still lacking convincing mechanism. This paper presents an analytical model for valuing derivatives subject to default by both counterparties. The default-free interest rates are modeled by the Market Models, while the default time is modeled by the reduced-form model as the first jump of a time-inhomogeneous Poisson process. All quantities modeled are market-observable. The closed-form solution gives us a better understanding of the impact of the credit asymmetry on swap value, credit value adjustment, swap rate and swap spread.

scholarly journals Performance Evaluation of Alternative Relative Orientation Procedures for UAV-based Imagery with Prior Flight Trajectory Information

2016 ◽  
Vol XLI-B3 ◽  
pp. 21-25 ◽  
Author(s):  
F. He ◽  
A. Habib
Keyword(s):  
Low Cost ◽  
Closed Form Solution ◽  
Experimental Tests ◽  
Form Solution ◽  
Relative Orientation ◽  
Conjugate Points ◽  
Flying Height ◽  
Reliable Estimate ◽  
Comparative Performance ◽  
The Impact

Thanks to recent advances at the hardware (e.g., emergence of reliable platforms at low cost) and software (e.g., automated identification of conjugate points in overlapping images) levels, UAV-based 3D reconstruction has been widely used in various applications. However, mitigating the impact of outliers in automatically matched points in UAV imagery, especially when dealing with scenes that has poor and/or repetitive texture, remains to be a challenging task. In spite of the fact that existing literature has already demonstrated that incorporating prior motion information can play an important role in increasing the reliability of the matching process, there is a lack of methodologies that are mainly suited for UAV imagery. Assuming the availability of prior information regarding the trajectory of a UAV-platform, this paper presents a two-point approach for reliable estimation of Relative Orientation Parameters (ROPs) of UAV-based images. This approach is based on the assumption that the UAV platform is moving at a constant flying height while maintaining the camera in a nadir-looking orientation. For this flight scenario, a closed-form solution that can be derived using a minimum of two pairs of conjugate points is established. In order to evaluate the performance of the proposed approach, experimental tests using real stereo-pairs acquired from different UAV platforms have been conducted. The derived results from the comparative performance analysis against the Nistér five-point approach demonstrate that the proposed two-point approach is capable of providing reliable estimate of the ROPs from UAV-based imagery in the presence of poor and/or repetitive texture with high percentage of matching outliers.

scholarly journals A Network-Based Impact Measure for Propagated Losses in a Supply Chain Network Consisting of Resilient Components

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Jesus Felix Bayta Valenzuela ◽  
Xiuju Fu ◽  
Gaoxi Xiao ◽  
Rick Siow Mong Goh
Keyword(s):  
Supply Chain ◽  
Numerical Study ◽  
Random Network ◽  
Continuous Distribution ◽  
Closed Form Solution ◽  
Form Solution ◽  
Supply Chain Network ◽  
Impact Measure ◽  
Focal Company ◽  
The Impact

The topology of a supply chain network affects the impacts of disruptions in it. We formulate a network-based measure of the impact of a disruption loss in a supply chain propagating downstream from an originating node. The measure takes into account the loss profile of the originating node, the structure of the supply network, and the resilience of the network components. We obtain an analytical expression for the impact measure under a beta-distributed initial loss (generalizable to any continuous distribution supported on the interval 0,1), under a breakthrough scenario (in which a fraction of the initial production loss reaches a focal company downstream as opposed to containment upstream or at the originating point). Furthermore, we obtain a closed-form solution for a supply chain network with a k-ary tree topology; a numerical study is performed for a scale-free network and a random network. Our proposed approach enables the evaluation of potential losses for a focal company considering its supply chain network structure, which may help the company to plan or redesign a robust and resilient network in response to different types of disruptions.

A Closed-Form Solution for the Global Quadratic Hedging of Options under Geometric Gaussian Random Walks

2019 ◽  
Keyword(s):  
Closed Form ◽  
Recursive Algorithm ◽  
Closed Form Solution ◽  
Form Solution ◽  
Closed Form Expression ◽  
Problem Solution ◽  
Underlying Asset ◽  
Quadratic Hedging ◽  
Hedging Problem ◽  
The Impact

This study obtains a closed-form solution for the discrete-time global quadratic hedging problem of Schweizer (1995) applied to vanilla European options under the geometric Gaussian random walk model for the underlying asset. This extends the work of Rémillard and Rubenthaler (2013), who obtained closed-form formulas for some components of the hedging problem solution. Coefficients embedded in the closed-form expression can be computed either directly or through a recursive algorithm. The author also presents a brief sensitivity analysis to determine the impact of the underlying asset drift and the hedging portfolio rebalancing frequency on the optimal hedging capital and the initial hedge ratio.

Sign in / Sign up

Export Citation Format

Share Document