• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.2 s.314
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• pp.32-38
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• 2007

This paper represents a Doherty amplifier (DPA) with analog predistorter (PD) to improve the linearity of the DPA while preserving the high efficiency. A third-order PD cancels fifth-order intermodulation (IM5) as well as third-order intermodulation (IM3) components by their same phase difference in the PD and DPA. This is accomplished by independently controlling their phase by using the phase-controlled error generator in the PD. Also, we confirm the phase-control ability of the error generator experimentally with a simple and accurate phase measurement setup. For experimental verification, a third-order PD has been implemented and tested in a 180-W DPA at the wide-band code division multiple access (WCDMA) band of 2.11-2.17 GHz. Two-tone test results show that significant cancellation of IM3 and IM5 components can be obtained. For four-carrier WCDMA applications, significant adjacent channel leakage ratio (ACLR) improvement is achieved over a wide range of output power levels. This technique is cost-effective and convenient due to its simple structure, compact size, and three control parameters.

• Journal of the Korean Society for Precision Engineering
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• v.6 no.4
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• pp.52-60
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• 1989

In order to control the transient torsional vibration of rotational shaft system, the torsional stiffness of it has been taken into account in modelling the plant. In this paper the observer and controller has been designed in two ways. One is to consider the torsional stiffness and the other is to idealize the rotational shaft as rigid body. The third order observer considering torsional stiffness shows stable response on computer simulation. When the observer is designed on assumption of the rotational shaft being rigid body, the reduced order observer shows stable response whereas the full order observer shows unstable response.

• Current Optics and Photonics
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• v.6 no.6
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• pp.576-582
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• 2022

Plasmonic high-order harmonic generation (HHG) is used in nanoscale optical applications because it can help in realizing a compact coherent ultrashort pulse generator on the nanoscale, using plasmonic field enhancement. The plasmonic amplification of nanostructures induces nonlinear optical phenomena such as second-order harmonic generation, third-order harmonic generation, frequency mixing, and HHG. This amplification also causes damage to the structure itself. In this study, the plasmonic amplification according to the design of a metal-coated sapphire conical structure is theoretically calculated, and we analyze the effects of this optical amplification on HHG and damage to the sample.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.1B
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• pp.1-6
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• 2005

Communication network is in a transition toward the NGN (Next Generation Networks) to accommodate the explosive demand of new services. The NGN allows the third-party application provisioning by defining the networks as layers of Services, Distributed Processing Environment and Transport. Especially, the Service layer can further be divided into Application and Service Component layer. In order to realize the third-party application provisioning, the Parlay Group has adopted an open Parlay API as an interface between the Application and the Service Component layer. Using Parlay API, the third parties may develop and deploy the IT-based applications at the Application layer exploiting the service components located within network operators' domain. In this paper, we present the implementation details about the Third Party Call Control (TPCC) Service using the third-party service logic based on Parlay API and Parlay X API, when SIP is used as a signaling protocol in Transport layer. Also, we compare the performance evaluation of both implementations.

• The Korean Journal of Air & Space Law and Policy
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• v.23 no.1
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• pp.3-32
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• 2008

In proportion to recent developments in aviation technology and growth of the air transport market, the risk of damages to third parties caused by aircrafts and the likelihood of unlawful interference on an aircraft in flight has grown larger. The war risk insurance market was paralyzed by the 9/11 terror event. And if another event on the scale of 9/11 occurs, compensations for third party damages will be impossible. Recognizing the need to modernize the existing legal framework and the absence of a globally accepted authority that deals with third party liability and compensation for catastrophic damage caused by acts of unlawful interference, the ICAO and various countries have discussed a liability and compensation system that can protect both third party victims and the aviation industry for the 7 years. In conclusion, in order to provide adequate protection for victims and the appropriate protection for air transport systems including air carriers, work on modernizing the Rome Convention should be continued and the new Convention should be finalized in the near future. Korea has not ratified the relevant international treaties, i.e. Rome Convention 1933, 1952 and 1978, and has no local laws which regulate the damage caused by aircraft to third parties on land. Consequently, it has to depend on the domestic civil tort laws. Most of the advanced countries in aviation such as the United States, England, Germany, France and even China, have incorporated the International Conventions to their national air law and governed carriers third party liability within their jurisdiction. The Ministry of Justice organized the Special Enactment Committee for Air Transport chapter under Commercial Law. The Air Transport chapter, which currently includes third party liability, is in the process of instituting new legislation. In conclusion, to settle such problems through local law, it is necessary to enact as soon as possible domestic legislation on the civil liability of the air carrier which has been connected with third party liability and aviation insurance.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.6
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• pp.71-78
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• 1989

The imput-output relations for nonlinear systems can be explicitly represented by the Volterra series and they can be characterized by the Volterra kernels. This study is concerned with modeling an elastomer force-displacement relation due to step inputs by utilizing the truncated Volterra series. Since it is practically impossible to apply step inputs that have infinite slope at zero time, the loads due to constant penetration(displacement) rate followed by constant penetration inputs are measured as an alternative approach and estimated for step inputs and then utilized for the truncated Volterra series models. One second order and one third order truncated Volterra series models have been employed to model the force-displacement relation which is one of the prominent properties to characterize the viscoelastic material. The third order truncated Volterra series model has better results, compared with those of the second order truncated Volterra series model.

• Bulletin of the Korean Chemical Society
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• v.8 no.5
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• pp.408-414
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• 1987

The rate of bromine-exchange reaction between antimony tribromide and ${\alpha}-phenyl-n-butyl$ bromide in nitrobenzene has been determined, using antimony tribromide labelled with Br-82. The results indicate that the exchange reaction follows the first-order kinetics with respect to the organic bromide, and either the second- or first-order kinetics with respect to antimony tribromide depending on its concentration. The third-order rate constant obtained was 7.50 ${\times}10^{-2}l^2mol^{-2}s^{-1}$ at 28$^{\circ}$C. Similar study on the bromine-exchange reaction between antimony tribromide and ${\alpha}$-phenyl-i-butyl bromide has also been carried out. The results of the study show the same kinetic orders as the ones observed with $\alpha$-phenyl-n-butyl bromide. The third-order rate constant observed was 2.40 ${\times} 10^{-2} l^2mol^{-2}s^{-1}$ at 28$^{\circ}$C. The activation energy, the enthalpy of activation and the entropy of activation for the two exchange reactions mentioned above have been determined. The reaction mechanisms for the exchange reactions are discussed.

• Steel and Composite Structures
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• v.43 no.1
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• pp.1-17
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• 2022

The free and forced nonlinear dynamic behaviors of Porous Functionally Graded Material (PFGM) plates are examined by means of a High-Order Implicit Algorithm (HOIA). The formulation is developed using the Third-order Shear Deformation Theory (TSDT). Unlike previous works, the formulation is written without resorting to any homogenization technique neither rule of mixture nor considering FGM as a laminated composite, and the distribution of the porosity is assumed to be gradually variable through the thickness of the PFGM plates. Using the Hamilton principle, we establish the governing equations of motion. The Finite Element Method (FEM) is used to compute approximations of the resulting equations; FEM is adopted using a four-node quadrilateral finite element with seven Degrees Of Freedom (DOF) per node. Nonlinear equations are solved by a HOIA. The accuracy and the performance of the proposed approach are verified by presenting comparisons with literature results for vibration natural frequencies and dynamic response of PFGM plates under external loading. The influences of porosity volume fraction, porosity distribution, slenderness ratio and other parameters on the vibrations of PFGM plate are explored. The results demonstrate the significant impact of different physical and geometrical parameters on the vibration behavior of the PFGM plate.

• The Korean Journal of Community Living Science
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• v.16 no.3
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• pp.75-85
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• 2005

This study was performed to clarify which variables affected a mother‘s empathic behavior shown in a mother-child play session. Mother’s empathy was videotaped and recorded during mother-child twenty minute play sessions. The variables considered in the research were the mother‘s parenting stress, age and education level, and the child’s sex and birth order. Twenty four mothers volunteered to participate in this study. The age of their children was restricted to 5 years. The results were as follows; First, mothers were verbally more accepting to their second or third child, and allowed their second of third child to lead more than their first child. And older mothers were more likely to accept their children's lead. Seconds, the mothers' parenting stress for acceptance of their children and stress of depression were higher in college graduate mothers than high school graduate mothers. Third, the mother's empathy and level of parenting stress did not show any significant relationships.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.75-75
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• 2003

All published and newly observed times of minimum light of the massive, early-type eclipsing binary star AH Cep were analyzed. After subtracting the light time effect due to the well-known third body from the residuals of the observed times of minimum light, it was found that the second-order Ο-C residuals varied in a cyclical way. It was assumed that the secondary oscillations were produced by a light time effect due to a fourth body so all the times of minimum light were reanalyzed with a differential least-squares scheme in order to obtain the light time orbits due to both the third and fourth bodies. The periods, eccentricities, semi-amplitudes of the light time orbits for the third and fourth-bodies were derived as : P$\_$3/=68.$\^$y/3 and P$\_$4/=9.$\^$y/3, e$_3$=0.53 and e$_4$=0.83, K$_3$=0.$\^$d/0585 and K$_4$=0.$\^$d/0045, respectively. The analysis of the radial velocities of AH Cep published so far, do not conflict with the hypothesis of the multiplicity of the system but their accuracies are not high enough to be useful to support the interpretation. Other properties of the distant bodies are discussed for assorted possible inclinations of their orbits.