Low-area Bit-parallel Systolic Array for Multiplication and Square over Finite Fields

Keewon Kim(김기원) 한국컴퓨터정보학회 2020 韓國컴퓨터情報學會論文誌 Vol.25 No.2

본 논문은 유한체상의 곱셈과 제곱을 동시에 실행 가능한 알고리즘에서 공통적인 연산 부분을 도출하고, 순차적인 처리를 통해서 하드웨어를 감소시키고 공간면에서 효율적인 비트-병렬 시스톨릭 어레이를 제안한다. 제안한 시스톨릭 어레이는 기존의 어레이에 비해 적은 공간 및 공간-시간 복잡도(area-time complexity)를 가진다. 기존의 구조들과 비교하면, 제안한 시스톨릭 어레이는 공간 복잡도면에서 Choi-Lee, Kim-Kim의 시스톨릭 어레이의 약 48%, 44% 감소되었으며, 공간-시간 복잡도면에서 약 74%, 44% 가량 감소되었다. 따라서 제안한 시스톨릭 어레이는 VLSI 구현에 적합하며 사물인터넷과 같이 하드웨어 제약이 있는 환경에서 기초적인 구성 요소로 적용할 수 있다. In this paper, we derive a common computational part in an algorithm that can simultaneously perform multiplication and square over finite fields, and propose a low-area bit-parallel systolic array that reduces hardware through sequential processing. The proposed systolic array has less space and area-time (AT) complexity than the existing related arrays. In detail, the proposed systolic array saves about 48% and 44% of Choi-Lee and Kim-Kim’s systolic arrays in terms of area complexity, and about 74% and 44% in AT complexity. Therefore, the proposed systolic array is suitable for VLSI implementation and can be applied as a basic component in hardware constrained environment such as IoT.

유한체상의 여분기저를 사용한 효율적인 멀티플렉서 기반 AB² 곱셈기

김기원(Keewon Kim) 한국컴퓨터정보학회 2020 韓國컴퓨터情報學會論文誌 Vol.25 No.1

본 논문에서는 유한체상의 여분 기저(redundant basis)를 사용한 모듈러 AB² 곱셈을 수행하는 멀티플렉서(multiplexer) 기반의 기법을 제안한다. 그리고 제안한 기법을 사용하여 효율적인 멀티플렉서 기반의 세미-시스톨릭(semi-systolic) AB² 곱셈기를 제안한다. 모듈러 AB² 곱셈기의 셀 내부의 연산을 멀티플렉서로 처리할 수 있는 수식을 유도한다. 멀티플렉서를 이용하여 셀을 구현하여, 셀의 지연시간을 감소시킨다. 기존의 구조들과 비교하면, 제안한 AB² 곱셈기는 Liu 등, Lee 등, Ting 등, 및 Kim-Kim의 곱셈기들의 AT 복잡도보다 약 80.9%, 61.8%, 61.8%, 및 9.5% 가량이 감소되었다. 따라서, 제안한 곱셈기는 VLSI(very large scale integration) 구현에 적합하며 다양한 응용에 쉽게 적용할 수 있다. In this paper, we propose a multiplexer based scheme that performs modular AB² multiplication using redundant basis over finite field. Then we propose an efficient multiplexer based semi-systolic AB² multiplier using proposed scheme. We derive a method that allows the multiplexers to perform the operations in the cell of the modular AB2 multiplier. The cell of the multiplier is implemented using multiplexers to reduce cell latency. As compared to the existing related structures, the proposed AB² multiplier saves about 80.9%, 61.8%, 61.8%, and 9.5% AT complexity of the multipliers of Liu et al., Lee et al., Ting et al., and Kim-Kim, respectively. Therefore, the proposed multiplier is well suited for VLSI implementation and can be easily applied to various applications.

유한체상의 효율적인 세미-시스톨릭 AB² 곱셈기

김기원(Keewon Kim) 한국컴퓨터정보학회 2020 韓國컴퓨터情報學會論文誌 Vol.25 No.1

본 논문에서는 유한체상의 SPB(shifted polynomial basis)를 사용한 효율적인 AB² 곱셈 알고리즘을 제안한다. SPB의 특징을 이용하여, AB² 곱셈을 위한 수식을 두 부분으로 분할하였다. 분할된 두 수식은 동시에 실행가능하며, 이를 병렬로 처리하는 알고리즘을 도출하였다. 그리고 제안한 알고리즘을 기반으로 효율적인 세미-시스톨릭(semi-systolic) AB² 곱셈기를 제안한다. 제안한 곱셈기는 기존의 곱셈기에 비해 낮은 공간-시간 복잡도(area-time complexity)를 가진다. 기존의 구조들과 비교하면, 제안한 AB² 곱셈기는 공간-시간 복잡도면에서 Wei, Wang-Guo, Kim-Lee, 및 Choi-Lee의 곱셈기들의 약 94%, 87%, 86%, 및 83% 가량이 감소되었다. 따라서 제안한 곱셈기는 VLSI(very large scale integration) 구현에 적합하며 다양한 응용의 기초적인 구성 요소로 쉽게 적용할 수 있다. In this paper, we propose an efficient AB² multiplication algorithm using SPB(shifted polynomial basis) over finite fields. Using the feature of the SPB, we split the equation for AB² multiplication into two parts. The two partitioned equations are executable at the same time, and we derive an algorithm that processes them in parallel. Then we propose an efficient semi-systolic AB² multiplier based on the proposed algorithm. The proposed multiplier has less area-time (AT) complexity than related multipliers. In detail, the proposed AB² multiplier saves about 94%, 87%, 86% and 83% of the AT complexity of the multipliers of Wei, Wang-Guo, Kim-Lee, Choi-Lee, respectively. Therefore, the proposed multiplier is suitable for VLSI implementation and can be easily adopted as the basic building block for various applications.

Bias voltage dependence of magnetic tunnel junctions comprising double barriers and CoFe/NiFeSiB/CoFe free layer

Kim, You Song,Chun, Byong Sun,Kim, Deok-kee,Hwang, Jae Yeon,Kim, Soon Sub,Rhee, J.R.,Kim, Keewon,Kim, Taewan,Kim, Young Keun IEEE 2006 IEEE transactions on magnetics Vol.42 No.10

The typical double-barrier magnetic tunnel junction (DMTJ) structure examined in this paper consists of a Ta 45/Ru 9.5/IrMn 10/CoFe 7/AlO<SUB>x</SUB>/free layer/AlO<SUB>x</SUB>/CoFe 7/IrMn 10/Ru 60 (nm). The free layer consists of an Ni<SUB>16</SUB>Fe<SUB>62</SUB>Si<SUB>8</SUB>B<SUB>14</SUB> 7 nm, Co<SUB>90</SUB>Fe<SUB>10</SUB> (fcc) 7 nm, or CoFe t<SUB>1</SUB>/NiFeSiB t<SUB>2</SUB>/CoFe t<SUB>1</SUB> layer in which the thicknesses t<SUB>1</SUB> and t<SUB>2</SUB> are varied. The DMTJ with an NiFeSiB-free layer had a tunneling magnetoresistance (TMR) of 28%, an area-resistance product (RA) of 86 k Ω μm<SUP>2</SUP>, a coercivity (H<SUB>c</SUB>) of 11 Oe, and an interlayer coupling field (H<SUB>i</SUB>) of 20 Oe. To improve the TMR ratio and RA, a DMTJ comprising an amorphous NiFeSiB layer that could partially substitute for the CoFe free layer was investigated. This hybrid DMTJ had a TMR of 30%, an RA of 68 k Ωμ m<SUP>2</SUP>, and a H<SUB>c</SUB> of 11 Oe, but an increased H<SUB>i</SUB> of 37 Oe. We confirmed by atomic force microscopy and transmission electron microscopy that H<SUB>i</SUB> increased as the thickness of NiFeSiB decreased. When the amorphous NiFeSiB layer was thick, it was effective in retarding the columnar growth which usually induces a wavy interface. However, if the NiFeSiB layer was thin, the roughness was increased and H<SUB>i</SUB> became large because of the magnetostatic Ne´el coupling.

Submicron-Sized MRAM Array with Local Field Switching Architecture

Keewon Kim,Injun Hwang,Tae-Wan Kim,Ji Young Bae,Young Jin Cho,Kwang-Seok Kim,Sung Hoon Choa 한국자기학회 2007 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

Chemically Homogeneous and Thermally Robust Ni_1–<i>x</i>Pt_<i>x</i>Si Film Formed Under a Non-Equilibrium Melting/Quenching Condition

Kim, Jinbum,Choi, Seongheum,Park, Taejin,Kim, Jinyong,Kim, Chulsung,Cha, Taeho,Lee, Hyangsook,Lee, Eunha,Won, Jung Yeon,Lee, Hyung-Ik,Hyun, Sangjin,Kim, Sunjung,Shin, Dongsuk,Kim, Yihwan,Kwon, Keewon American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.1

<P>To synthesize a thermally robust Ni1-xPtxSi film suitable for ultrashallow junctions in advanced metal-oxide-semiconductor field-effect transistors, we used a continuous laser beam to carry out millisecond annealing (MSA) on a preformed Ni-rich silicide film at a-local surface temperature above 1000 degrees C while heating the substrate to initiate a phase transition. The melting and quenching process by this unique high-temperature MSA process formed a Ni1-xPtxSi film with homogeneous Pt distribution across the entire film thickness. After additional substantial thermal treatment up to 800 degrees C, the noble Ni1-xPtxSi film maintained a low-resistive phase without agglomeration and even exhibited interface flattening with the underlying Si substrate.</P>

상지동맥 혈관계의 모델링과 혈유동의 전산수치해석

김기원(Keewon Kim),김재욱(Jaeuk U. Kim),백현만(Hyun Man Beak),김성균(Sung Kyun Kim) 대한기계학회 2016 大韓機械學會論文集B Vol.40 No.4

하지혈관에 비해 상지혈관질환은 드물기 때문에 상지혈관계에 대한 실험적, 수치해석적 연구는 매우 드물다. 본 논문에서는 최초로 MRA 영상데이터로부터 한국 성인 왼팔의 혈관계, 상완동맥에서 1 ㎜ 이상의 손가락동맥들에 이르는, 3차원 컴퓨터 모델을 제작하였다. 이 모델에 대해 수치해석을 수행하여 정상, 주기유동에 대한 속도장, 압력장을 계산하였고 주요 분지관에서의 유량분배와 벽전단응력분포에 대해 분석하였다. Since arterial disease in the upper extremity is less common than that in the lower extremity, experimental and numerical investigations related to upper extremity have been rarely performed. We created a three-dimensional model of the arteries, larger than approximately 1 mm, in a Korean adult"s left hand (from brachial to digital arteries), from 3T magnetic resonance imaging (MRI) data. For the first time, a three-dimensional computational fluid dynamic method was employed to investigate blood flow velocity, blood pressure variation, and wall shear stress (WSS) on this complicated artery system. Investigations were done on physiological blood flows near the branches of radial and deep palmar arch arteries, and ulnar and superficial palmar arch arteries. The flow is assumed to be laminar and the fluid is assumed to be Newtonian, with density and viscosity properties of plasma.

상지 동맥혈관계의 혈유동 전산수치해석

김기원(Keewon Kim),전영선(Young Sun Jeon),이균범(Kyun Bum Lee),김재욱(Jeauk U. Kim),김성균(Sung Kyun Kim) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11

Development of a female animal model for anatomical and functional assessment of the pelvic autonomic nerves in women

( Seungmee Lee ),( Se Jeong Kim ),( Maria Lee ),( Hee Seung Kim ),( Keewon Kim ),( Seung-bum Ryoo ),( Jeong-hwa Seo ),( Sang Youn Kim ),( Ji Won Park ),( Kyoung Sup Hong ),( Hak Jae Kim ),( Chang Wook 대한산부인과학회 2016 대한산부인과학회 학술대회 Vol.102 No.-

목적: Although nerve-sparing surgery has been introduced for female patients with the pelvic tumors, its efficacy is still controversial because of no consensus of the surgical technique and a lack of the physiologic understanding of the pelvic autonomic nerves. Thus, we developed a female animal model for anatomical and functional assessment of the pelvic autonomic nerves in women. 방법: We used female domestic swine, weighing 25 to 30 kg. All procedures were performed under sterile conditions, and anesthetic procedure was induced with ketamine and maintained with enflurane inhalation through intubation. We sacrificed three swine for the anatomical assessment, and eight swine for the functional assessment of the pelvic autonomic nerves. Moreover, we developed a new stimulation system using a bipolar instrument and peripheral nerve stimulator, and made a new monitoring system for evaluating contraction of bladder, vagina and rectum. 결과: Like human, we found bilateral sympathetic trunk and ganglions run beside aorta and inferior vena cava, and thin fibers from sympathetic ganglions joins together to become the superior hypogastric nerve on the aortic bifurcation, which runs bilaterally as the inferior hypogastric nerves. Moreover, we found parasympathetic nerves from S2-S4, which join together with inferior hypogastric nerves and form the pelvic plexus. Then, we found the rectal, vesical and uterine branches of the pelvic plexus. For the functional assessment, we simulated the pelvic parasympathetic nerves, and then found regular contraction in bladder and rectum. On the other hand, sympathetic nerve stimulation decreased the contraction. However, vaginal contraction was different. These results were similar to those from five patients with cervical cancer whose functions of the pelvic autonomic nerves were evaluated during surgery. 결론: The female swine model may be adequate for the anatomical and functional assessment of the pelvic autonomic nerves in women.

Analysis of Deregistration Attacks in 5G Standalone Non-Public Network

Keewon Kim(김기원),Kyungmin Park(박경민),Tae-Keun Park(박태근) 한국컴퓨터정보학회 2021 韓國컴퓨터情報學會論文誌 Vol.26 No.9

본 논문에서는 5G SNPN (Standalone Non-Public Network)에서 등록 해제 공격(Deregistration Attack)의 가능 여부를 3GPP 표준 문서에 근거하여 분석한다. 등록 해제 공격에서 공격자는 AMF(Access and Mobility Management Function)에 정상적으로 등록되어 있는 UE로 가장하여 스푸핑된 RRC (Radio Resource Control) 연결을 설정을 시도하여 AMF가 기존의 UE의 등록을 해제하게 한다. 기존의 등록 해제 공격은 UE가 등록되어 있는 AMF에게 스푸핑된 RRC 연결을 시도하는데, 본 논문에서는 추가적으로, 사용자가 등록 되어 있는 AMF와는 다른 새로운 AMF에게 공격자가 스푸핑된 RRC 연결 설정을 시도하였을 때에도, 등록 해제 공격이 가능한지 분석한다. 분석 결과, 5G 이동통신 네트워크 시스템이 3GPP 표준을 충실히 준수하여 구현된 경우에는 UE의 등록 해제공격은 불가능한 것으로 판단된다. In this paper, we analyze the possibility of deregistration attack in 5G SNPN (Standalone Non-Public Network) based on 3GPP standard document. In the deregistraion attack, the attacker pretends to be a UE that is normally registered with AMF (Access and Mobility Management Function) and attempts to establish a spoofed RRC (Radio Resource Control) connection, causing AMF to deregister the existing UE. The existing deregistration attack attempts a spoofed RRC connection to the AMF in which the UE is registered. In addition, this paper analyzes whether deregistration attack is possible even when an attacker attempts to establish a spoofed RRC connection to a new AMF that is different from the registered AMF. When the 5G mobile communication network system is implemented by faithfully complying with the 3GPP standard, it is determined that a deregistration attack of a UE is impossible.