VERTICAL TYPE TRANSISTOR WITH HETERO-JUNCTION STRUCTURE AND METHOD FOR MANUFACTURING SAME

본 발명의 일 실시예에 따른 이종접합 구조의 수직형 트랜지스터 제조 방법은, 제1 전자 이동도를 가지는 제1 물질로 구성되는 제1 레이어, 상기 제1 전자 이동도 보다 큰 제2 전자 이동도를 가지는 제2 물질로 구성되는 제2 레이어 및 상기 제1 물질로 구성되는 제3 레이어를 포함하는 다층 구조를 생성하는 단계와, 상기 다층 구조에 대해 수직으로 소스(source), 드레인(drain), 게이트(gate)를 형성하여 수직형 트랜지스터를 제조하는 단계를 포함할 수 있다

지수함수 기반 S-Box의 선형 독립 이차 방정식의 수에 관한 연구

학위논문(석사) - 한국과학기술원 : 정보보호대학원, 2024.2,[i, 22 p. :]One of the important factors that determines the security of an S-box on the point of view of algebraic attacks is the number of linearly independent multivariate quadratic equations on $\mathbb{F}_2$ it satisfies. Many previous researches analyzed the equations on $\mathbb{F}_2$ of S-boxes based on power functions, as they can be used to build an S-box of an arbitrary size. Courtois et al.\ proved the number of equations for an inverse S-box of arbitrary size, and expanding upon that, Nawaz et al.\ presented an algorithm to count the number of equations for an S-box based on an arbitrary power function. In this paper, we extend the previous results to apply to $\mathbb{F}_{2^m}(m \ne 1, m|n)$, a subfield of $\mathbb{F}_{2^n}$. We first present an algorithm to count the number of quadratic equations of an S-box on the subfield. Next, we give proof that for one of the most frequently used S-boxes, the inverse S-box set on $\mathbb{F}_{2^n}$, the number of linearly independent quadratic equations on $\mathbb{F}_{2^m}$ is given as $n/m-1$. We expect to be able to apply the principles of algebraic attacks and analysis on subfields to new types of attacks which has not been researched before.한국과학기술원 :정보보호대학원

MEMS 배열을 이용한 초음파 집속 빔 설계 및 특성

학위논문(석사) - 한국과학기술원 : 전기및전자공학과, 2014.2, [ viii, 55 p. ]Ultrasound has recently received increased attention and acceptance as the therapeutic device. Especially non-invasive stimulation using focused ultrasound has been a promising field in therapeutic application. A non-invasive treatment has advantages over alternative surgical procedures or insertion of needles which carry with them the risk of infection and pain. With recent advancements in focused ultrasound (FUS) technique, focused acoustic energy can be delivered to specific areas of biological tissues, as small as a few millimeters in diameter. However, there are limitations in which conventional piezoelectric transducers used in above applications. Challenging issues in single bulk piezoelectric transducer, such as fixed focal depth, impedance matching layer, and high voltage requirement have been effectively handled by MEMS. A significant advantage of using the MEMS is that large transducer arrays can be implemented in a small area. This enables the delivery of high acoustic power to the target area without generating high pressure on the surface of the transducer. This thesis presents optimal configuration of MEMS array which effectively stimulate targeted local area, by using MATLAB code simulation based on Rayleigh-Sommerfeld integral. As a preliminary step, A 15 by 15 pMUT rectangular array was used to verify simulation model. Beam profile measurements on this transducer made in an acoustic tank were compared with the beam profile predicted by simulation. The results showed good agreement with the simulation results. The acoustic focal region (AFR), the region bounded by the intensity contour lying 3 dB below the peak intensity, was located 1.775mm in the z-axis direction from the surface of the transducer. At the AFR, I_spta from the simulation showed the largest value of 739 mW/한국과학기술원 : 전기및전자공학과

Wireless power transfer apparatus for implantable medical device in human body using focused ultrasound beamforming technique

본 발명은 초음파 빔포밍 기술을 이용하여 인체 내에 이식된 의료장치로의 무선전력전송장치에 관한 기술로서, 빔형성부는 지연시간이 특정 순서로 계산된 구동 신호들을 위상배열 초음파 트랜스듀서에 출력하고 상기 위상배열 초음파 트랜스듀서는 구동 신호의 지연시간에 따라 출력하는 초음파 빔들의 초점 위치를 변화시키고 인체 내부의 의료용 이식장치로 초음파 빔들을 집속시켜 전기로 변환하여 충전장치에 전력을 충전하는 초음파 빔포밍 기술을 이용한 인체 내에 이식된 의료장치로의 무선전력전송장치에 관한 기술이다