• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.6
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• pp.584-590
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• 2003

In this paper, the numerical characteristics of the recently developed Envelope ADI-FDTD are investigated. Through numerical simulations, it is shown that the unconditional stability of the Envelope ADI-FDTD is independent of time step size and we can get better dispersion accuracy than the traditional ADI-FDTD by analyzing the envelope of the signal. This fact gives the opportunity for extending the temporal step size to the Nyquist limit in certain cases. Numerical results show that the Envelope ADI-FDTD can be used as an efficient electromagnetic analysis tool especially in the single frequency or band limited systems.

• Journal of the Korean Data and Information Science Society
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• v.12 no.2
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• pp.35-45
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• 2001

We introduce a new percentile envelope for diagnosing supernormality in regression analysis. Furthermore, we compare this percentile envelope, which is much simpler and easier, with Atkinson's and Flack and Flores' envelopes. Using percentile envelope, we investigate characteristics of normal probability plots with envelope for error distributions when supernormality is occurred. We give cautions that test result for normality assumption of errors can be reached the wrong conclusion by supernormality.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.3
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• pp.40-47
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• 2009

This paper presents new drain bias scheme for the linearity enhancement of envelope tacking power amplifiers for W-CDMA base-stations. In the conventional envelope tracking power amplifiers, the drain bias voltage is lowered close to the knee voltage of transistor, resulting in the severe linearity degradation. To solve this problem, it is proposed in this paper that the amplifier is biased in the conventional class AB mode with a fixed drain bias voltage if the input envelope is low and in the envelope tracking mode otherwise. Moreover, the drain bias in the envelope tracking mode is newly determined to minimized the distortion. To verify the effectiveness of the proposed bias scheme, simulation is performed on the W-CDMA based-station envelope tracking power amplifier using class AB Si-LDMOS power amplifier. It is shown from the simulation that the proposed bias scheme allows a drastic linearity enhancement with the comparable efficiency enough to meet the requirement of W-CDMA base-station without additional linearization techniques.

• The Journal of Korean Society of Virology
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• v.26 no.2
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• pp.141-150
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• 1996

본 연구에서는 $CD4^+$ T 세포를 일회성으로 감염시킬 수 있고 $CD4^+$ T 세포에 HIV-1 envelope 유전자를 전달할 수 있는 바이러스 입자를 생산하는 HIV-1 complementation system을 개발하였고 이 system을 이용하여 $CD4^+$ T 세포에 선택적으로 HIV-1 envelope 당단백질을 발현시켰다. 이 system은 Gag/Gag-Pol expressor와 Env expressor로 구성되어있다. Gag/Gag-Pol expressor는 바이러스 입자 생산에 필요한 구조단백질과 기능단백질을 발현시키지만 packaging signal이 결핍되어 바이러스 입자로 유전자가 들어가지 못하도록 제조되었다. Env expressor는 Tat, Rev와 envelope 당단백질을 발현시키고 packaging signal을 갖고 있어 바이러스 입자로 envelope 유전자가 들어가도록 제조되었다. Gag/Gag-Pol expressor로부터 Gag와 Gag-Pol의 발현은 Rev 단백질을 요구하였고 Env expressor로부터 Rev 단백질 이 제공될 때 Gag와 Gag-Pol 단백질은 효율적으로 발현되었다. Gag/Gag-Pol과 Env expressor로 cotransfection된 COS-1 세포에서 $CD4^+$ T 세포를 일회성으로 감염시킬 수 있는 바이러스 입자가 생산되었다. 생산된 바이러스 입자는 $CD4^+$ T 세포에 HIV-1 envelope 유전자를 전달하여 envelope 당단백질을 발현시켰고 복제 가능한 자손 바이러스의 생성을 유도하지 못하였다. 본 연구에서 개발된 방법은 $CD4^+$ T 세포에서 envelope 당단백질의 기능을 분석하고 관심 있는 유전자를 $CD4^+$ T 세포에 전달하는 바이러스 입자의 생산에 이용할 수 있다.

• Bulletin of the Korean Mathematical Society
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• v.44 no.4
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• pp.589-596
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• 2007

In this paper we prove that the extension of pure injective module is pure injective if and only if the cotorsion envelope and the pure injective envelope of any R-module M are isomorphic over M. And we prove that if the product of pure injective envelopes of flat modules is a pure injective envelope and the product of flat covers is a flat cover, then the product of cotorsion envelopes is a cotorsion envelope.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.2
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• pp.63-68
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• 2015

This paper presents the algorithm for envelope protection of helicopters. The algorithm consists of two feedback control loops: inner loop and outer loop. As an inner loop control, model following control is designed to meet the ADS-33 handling qualities specification by minimizing the tracking errors between the responses of the actual model and those of the command filter. In order to implement envelope protection, saturation limiter is imposed to command channels in command filter, whose limits are computed corresponding to the envelope limit. Fast model predictive control is designed as an outer loop control to deal with saturation constraints generated by the inner loop envelope protection and also imposed by outer loop envelope protection variables. Simulation results show that the proposed algorithm yields good envelope protection performance.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.8
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• pp.693-700
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• 2007

We can predict spatial acoustic pressure distribution on the plane of interest by using acoustic holography. However, the information embedded in the distribution plot is usually much more than what we need: for example, source locations and their overall propagation pattern. One possible candidate to solve the problem is complex envelope analysis. Complex envelope analysis extracts slowly-varying envelope signal from a band signal. We have attempted to extend this method to space domain so that we can have spatial information that we need. We have to modulate two dimensional data for obtaining spatial envelope. Although spatial modulation basically follows the same concept that is used in time domain, the algorithm for the spatial modulation turns out to be different from temporal modulation. We briefly describe temporal complex envelope analysis and extend it to spatial envelope of 2-D acoustic field by introducing geometric transformation. In the end, the results of applying the spatial envelope to the holography are envisaged and verified.

• Korean Journal of Computational Design and Engineering
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• v.6 no.2
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• pp.89-100
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• 2001

Swept volume is the sweeping region of moving objects. It is used in various applications such as interference detection in assembly design, visualization of manipulator motions in robotics, simulation of the volume removal by a cutter in NC machining. The shape of swept volume is defined by the envelope, which is determined by the boundary of moving objects and its direction of motion. In order to implement the generation of swept volume, researchers have taken much effort to develop the techniques how to generate the envelope. However, their results are confined to envelope generated only in simple shape objects, such as polyhedra or quadric surfaces. This study provided the envelope generation algorithm of NURBS objects. Characteristic points were obtained by applying the geometric conditions of envelope to NURBS equations, and then characteristic curves were created by means of interpolating those points. Silhouette edges were determined in the following procedures. First, two adjacent surfaces which have the same edge were found from B-Rep data. Then, by taking the scalar product of velocity vector of a point on that edge with each normal vector on two surfaces, silhouette edges were discriminated. Finally, envelope was generated along moving direction in the form of ruled surfaces by using both the partial information between initial and final position of objects affecting envelope along with characteristic curves and silhouette edge. Since this developed algorithm can be applied not only to NURBS objects but also to their Boolean objects, it can be used effectively in various applications.

• Applied Microscopy
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• v.41 no.1
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• pp.13-20
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• 2011

The ultrastructure of the matured egg envelope in Pond smelt, Hypomesus nipponensis belonging to Osmeridae, Osmeriformes were investigated by routine light and electron microscopes. The matured egg have two egg envelopes and have a single micropyle, which is thought to the pathway of sperm in the area of the animal pole. An outer egg envelope was surrounded by a follicular layer and outer surface of inner egg envelope have structure with high electron density. Also, the inner egg envelope consisted of 6 horizontal lamellae with higher electron density alternating with 5 interlamellae of lower electron density. Many grooves distributed on the outer surface of outer egg envelope, and the outer surface of inner egg envelope was covered by amorphous structures. In conclusion, the egg of teleost is surrounded by one egg envelope according to the studies on morphology of egg envelope up to the present. The fact that have two egg envelopes is a species specificity of Pond smelt and these ultrastructural characters of egg envelope can be utilized in taxonomy of teleost.

• Journal of Ocean Engineering and Technology
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• v.30 no.2
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• pp.134-140
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• 2016

An envelope protection system is a control system that allows a submarine to operate freely using its own operational envelope without exceeding the structural limit, dynamic limit, and control input limit. In this paper, an envelope protection system for the pitch angle of a submarine is designed using a dynamic trim algorithm. A linear quadratic regulator and artificial neural network are used for the true dynamics approximation. A submarine maneuvering simulation program developed using experimental data is used to validate the designed envelope protection system. Simulation results show the effectiveness of the designed envelope protection system.