• 제목/요약/키워드: Inversion

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PROBLEMS IN INVERSE SCATTERING-ILLPOSEDNESS, RESOLUTION, LOCAL MINIMA, AND UNIQUENESSE

  • Ra, Jung-Woong
    • 대한수학회논문집
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    • 제16권3호
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    • pp.445-458
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    • 2001
  • The shape and the distribution of material construction of the scatterer may be obtained from its scattered fields by the iterative inversion in the spectral domain. The illposedness, the resolution, and the uniqueness of the inversion are the key problems in the inversion and inter-related. The illposedness is shown to be caused by the evanescent modes which carries and amplifies exponentially the measurement errors in the back-propagation of the measured scattered fields. By filtering out all the evanescent modes in the cost functional defined as the squared difference between the measured and the calculated spatial spectrum of the scattered fields from the iteratively chosen medium parameters of the scatterer, one may regularize the illposedness of the inversion in the expense of the resolution. There exist many local minima of the cost functional for the inversion of the large and the high-contrast scatterer and the hybrid algorithm combining the genetic algorithm and the Levenberg-Marquardt algorithm is shown to find efficiently its global minimum. The resolution of reconstruction obtained by keeping all the propating modes and filtering out the evanescent modes for the regularization becomes 0.5 wavelength. The super resolution may be obtained by keeping the evanescent modes when the measurement error and instance, respectively, are small and near.

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Textual Inversion을 활용한 Adversarial Prompt 생성 기반 Text-to-Image 모델에 대한 멤버십 추론 공격 (Membership Inference Attack against Text-to-Image Model Based on Generating Adversarial Prompt Using Textual Inversion)

  • 오윤주;박소희;최대선
    • 정보보호학회논문지
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    • 제33권6호
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    • pp.1111-1123
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    • 2023
  • 최근 생성 모델이 발전함에 따라 생성 모델을 위협하는 연구도 활발히 진행되고 있다. 본 논문은 Text-to-Image 모델에 대한 멤버십 추론 공격을 위한 새로운 제안 방법을 소개한다. 기존의 Text-to-Image 모델에 대한 멤버십 추론 공격은 쿼리 이미지의 caption으로 단일 이미지를 생성하여 멤버십을 추론하였다. 반면, 본 논문은 Textual Inversion을 통해 쿼리 이미지에 personalization된 임베딩을 사용하고, Adversarial Prompt 생성 방법으로 여러 장의 이미지를 효과적으로 생성하는 멤버십 추론 공격을 제안한다. 또한, Text-to-Image 모델 중 주목받고 있는 Stable Diffusion 모델에 대한 멤버십 추론 공격을 최초로 진행하였으며, 최대 1.00의 Accuracy를 달성한다.

Mass Transfer Modelling of Asymmetric Membrane Formation by Phase Inversion

  • 김제영;이환광;백기전;김성철
    • 한국막학회:학술대회논문집
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    • 한국막학회 1997년도 추계 총회 및 학술발표회
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    • pp.81-82
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    • 1997
  • 1. Introduction : The growth of membrane science was initiated by the invention of asymmetric membrane which can be formed by the technique known as phase inversion. The basic procedure of phase inversion involves casting a thin film of polymer solution onto a suitable substrate followed by immersion in a coagulation bath (quench step). Therefore, events occurring during the quench period, at which time solvent-nonsolvent exchange and eventual polymer precipitation take place, can play a controlling role in the determination of ultimate membrane structure.

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이온 주입시킨 n형 실리콘 반전층에 대한 전자상태의 Self-consistent계산 (Self-consistent Calculation of Electronic States in Implanted n-Type Silicon Inversion Layers)

  • 김충원;한백형
    • 대한전자공학회논문지
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    • 제25권2호
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    • pp.188-195
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    • 1988
  • The electronic states in implanted n-type silicon inversion layers have been calculated by solving Schrodinger and Poisson's equations self-consistently. The results show that implantation affects seriously energy levels, populations, and electron distribution of n-type silicon inversion layers. The calcualted channel charge is in excellent agreement with the experimental data reported elsewhere. This analysis is expected to provide powerful means to evaluate the performance of implanted n-channel MOSTs.

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Small CMOS Temperature Sensor Using MOSFETs in the Intermediate-Inversion Region

  • Park, Tai-Soon;Park, Sang-Gyu
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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    • pp.1086-1087
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    • 2009
  • A small temperature sensor is designed in a 0.35um CMOS process. Transistors operating in the intermediate inversion region are employed in the core of the sensor. This temperature sensor operates in $-50^{\circ}C{\sim}120^{\circ}C$ with ${\pm}2^{\circ}C$ of accuracy after two-point calibration. This temperature sensor can be placed in the active pixel area of a display panel to measure the temperature of the display panel for temperature compensation.

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차분 전력 분석에 안전한 역원기의 설계 (DPA-Resistant Design of the Inverter)

  • 김희석;조영인;한동국;홍석희
    • 한국정보통신설비학회:학술대회논문집
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    • 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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    • pp.340-344
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    • 2008
  • In the block cipher, DPA-resistant masking methods make an appropriation of extremely high cost for the non-linear part. Block ciphers like AES and ARIA use the inversion operation as this non-linear part. This make various countermeasures be proposed for reducing the cost of masking inversion. In this paper, we propose the efficient masking inverter by rearranging the masking inversion operation over the composite field and finding duplicated multiplications.

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Autopilot Design for Agile Missile with Aerodynamic Fin and Thrust Vecotring Control

  • Lee, Ho-Chul;Choi, Yong-Seok;Choi, Jae-Weon
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2003년도 ICCAS
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    • pp.525-530
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    • 2003
  • This paper is concerned with a control allocation strategy using the dynamic inversion which generates the nominal control input trajectories, and autopilot design using the time-varying control technique which is time-varying version of pole placement of linear time-invariant system for an agile missile with aerodynamic fin and thrust vectoring control. Dynamic inversion can decide the amount of the deflection of each control effector, aerodynamic fin and thrust vectoring control, to extract the maximum performance by combining the action of them. Time-varying control technique for autopilot design enhance the robustness of the tracking performance for a reference command. Nonlinear simulations demonstrates the dynamic inversion provides the effective nominal control input trajectories to achieve the angle of attack command, and time-varying control technique exhibits good robustness for a wide range of angle of attack.

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수정된 Levenberg-Marquardt 역산방법에 의한 한반도 남부의 추계학적 지진 요소 평가 (Inversion of Stochastic Earthquake Model Parameters using the Modified Levenberg-Marquardt′s method in Korea)

  • 연관희;;박동희;장천중
    • 한국지진공학회:학술대회논문집
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    • 한국지진공학회 2002년도 춘계 학술발표회 논문집
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    • pp.20-27
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    • 2002
  • Conventional Levenberg-Marquardt's nonlinear inversion method is simply modified by taking into account the second derivatives of the Hessian matrix so as to give robust inversion results. The weight of the second derivative terms is determined by the value of so-called λ in Levenberg-Marquardt's method. The new inversion method is applied to observed data from small-to-moderate earthquakes to simultaneously evaluate the modes parameters of the stochastic point-source model in and around the Korean Peninsula. Best estimates of the stochastic model parameters are obtained along with their statistics and compared with the previous results. Overall characteristics of the model parameters are found to be more of those of interplate than intraplate tectonic region.

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A Case Study on the Development of an Elevated Subsidence Inversion Over a Surface Low Pressure System

  • Kim, Kyung-Eak;Ko, Hye-Young;Heo, Bok-Haeng;Ha, Kyung-Ja
    • 한국지구과학회지
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    • 제31권5호
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    • pp.531-538
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    • 2010
  • This study presents the development of an elevated subsidence inversion over a surface low pressure system, which was formed along the Changma front or Meiu-Baiu front. The results of our analysis strongly suggest that the inversion is dissimilar to those formed in anticyclonic situations but is instead similar to the onion-shaped sounding found in wake low. The present analysis indicates that the observed elevated inversion resulted from the intrusion of stratospheric air associated with tropopause folding.

전기설비용 PET의 절연파괴와 공간전하효과에 관한 연구 (A Study on the Effect of Space Charge and tole Dielectric Breakdown of PEF for Electric Installation)

  • 윤성도;박상현;정학수;서장수;박중순;국상훈
    • 한국조명전기설비학회:학술대회논문집
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    • 한국조명전기설비학회 1992년도 추계학술발표회논문집
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    • pp.37-40
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    • 1992
  • This paper examined the existance behavior of charged particles by measuring polarity inversion current Thermal Stimulate Current (TSC) and analysed appearance mechanism of polarity inversion current Peak and Also investigated relation between ionic space charge format ion and dielectric breakdown by measuring D.C breakdown impulse breakdown D.C - impulse superposition as a sample of FET. As a result. lie found that dielectric breakdown is likely to happen due to ionic space charge at the transient state when applied polarity inversion voltage and that charged partion of TSE Peak at the high temperature was the same as that of polarity inversion current. Also there was no effect on ionic space charge about the dielectric breakdown in stationary state when applied D.C voltage.

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