Synthetic antiferromagnetic spintronics

Duine, R. A.,Lee, Kyung-Jin,Parkin, Stuart S. P.,Stiles, M. D. Nature Publishing Group UK 2018 NATURE PHYSICS Vol.14 No.3

<P>Spintronic and nanomagnetic devices often derive their functionality from layers of different materials and the interfaces between them. We discuss the opportunities that arise from synthetic antiferromagnets consisting of two or more ferromagnetic layers that are separated by metallic spacers or tunnel barriers and have antiparallel magnetizations.</P>

Non-Universal Aspects of Electromotive Forces Induced by Domain-Wall Motion

Rambert Duine 한국자기학회 2010 한국자기학회 학술연구발표회 논문개요집 Vol.2010 No.12

New perspectives for Rashba spin–orbit coupling

Manchon, A.,Koo, H. C.,Nitta, J.,Frolov, S. M.,Duine, R. A. Nature Publishing Group, a division of Macmillan P 2015 Nature materials Vol.14 No.9

In 1984, Bychkov and Rashba introduced a simple form of spin–orbit coupling to explain the peculiarities of electron spin resonance in two-dimensional semiconductors. Over the past 30 years, Rashba spin–orbit coupling has inspired a vast number of predictions, discoveries and innovative concepts far beyond semiconductors. The past decade has been particularly creative, with the realizations of manipulating spin orientation by moving electrons in space, controlling electron trajectories using spin as a steering wheel, and the discovery of new topological classes of materials. This progress has reinvigorated the interest of physicists and materials scientists in the development of inversion asymmetric structures, ranging from layered graphene-like materials to cold atoms. This Review discusses relevant recent and ongoing realizations of Rashba physics in condensed matter.

Kinetic and Spectral Investigations on $Ca^{2+}$ - and Sr$^{2+}$ -containing Methanol Dehydrogenases

Kim, Si-Wouk,Kim, Chun-Sung,Lee, Jung-Sup,Koh, Moon-Joo,Yang, Song-Suk,Duine, Johannis-A.,Kim, Young-Min The Microbiological Society of Korea 1997 The journal of microbiology Vol.35 No.3

Bothl $Ca^{2+}$ and Sr$^{2+}$-containing methanol dehydrogenases (MDH) were purified to homogeneity with yields of 48% and 42%, respectively, from Methylabacillus methanolovorus sp. strain SK5. Most of the biochemical and structural properties were similar to each other. However, some differences were found: (1) although the overall shape of the absorption spectrum of Sr$^{2+}$-MDH was very similar to that of $Ca^{2+}$-MDH, the absorption intensity originating from the cofactor in Sr$^{2+}$. MDH was higher than that in $Ca^{2+}$-MDH. Small blue shift of the maximum was also observed. These are probably due to a difference in redox state of the cofactors in $Ca^{2+}$ and Sr$^{2+}$-MDH; (2) Sr$^{2+}$-MDH was more heat-stable than $Ca^{2+}$-MDH above 56$^{\circ}C$; (3) the V$_{max}$ values for the methanol-dependent activities of Sr$^{2+}$- and $Ca^{2+}$-MDH in the presence of 3 mM KCN were 2.038 and 808 nmol/mg protein/min, respectively. In addition, the $K_{m}$ values of Sr$^{2+}$ and $Ca^{2+}$ MDH for methanol were 12 and 21 $\mu$M, respectively; (4) the endogenous activity of $Ca^{2+}$-MDH was more sensitive than that of Sr$^{2+}$-MDH in the presence of cyanide; (5) Diethyl pyrocarbonate treatment increased the enzyme activities of $Ca^{2+}$- and Sr$^{2+}$-MDH 4.2- and 1.4-folds, respectively. These results indicate that Sr$^{2+}$ stabilizes the structural conformation and enhances the activity of MDH more than $Ca^{2+}$.

City logistics through the canals? A simulation study on freight waterborne transport in the inner-city of Amsterdam

J.H.R. van Duin,R. Kortmann,S.L. van den Boogaard 서울시립대학교 도시과학연구원 2014 도시과학국제저널 Vol.18 No.2

This study investigates whether distributing goods across the water to the city of Amsterdam can be a potential future solution considering the busy traffic of the pleasure crafts and touring boats on the canals. A simulation model was developed to analyse the logistics performances and traffic influences for different fleet size configurations. The simulation tests have shown that four vessels are needed to guarantee the requested delivery times, a sufficient loading rate (82%) was generated for each ship, and no significant delays will happen due to interaction with other water traffic. Conclusion of this study is that a waterborne city logistics concept through the canals of Amsterdam has demonstrated the capability to reduce congestion in the inner-city and is able to satisfy the delivery requirements of the shopkeepers without significant interference with other waterborne traffic.

Ontology-based multi-agent system for urban freight transportation

Nilesh Anand,Ron van Duin,Lori Tavasszy 서울시립대학교 도시과학연구원 2014 도시과학국제저널 Vol.18 No.2

Congestion, pollution, and safety are some of the most worrisome side-effects of the urban goods movement activities. These problems are generally attributed to the underlying characteristics of the domain such as heterogeneous stakeholders, their conflicting objectives and resulting distributed decision-making. Such autonomous decision-making stakeholders do not efficiently cooperate and coordinate while performing city logistics activities. The ensuing inefficient use of resources (e.g. goods delivery vehicle, time, etc.) gives rise to the above-mentioned problems. To reduce the negative externalities of urban goods movement, we first must understand the decision-making process of the city logistics stakeholder under different situations. Agent-based simulation modelling technique is such an approach where distributed decision-making of the multiple stakeholders can be included by modelling each entity as an autonomous agent. In this paper, we propose the use of a knowledge data model of urban freight domain – city logistics ontology – to develop an agent-based model. City logistics ontology is a knowledge model which includes city logistics entities (e.g. stakeholders, resources, etc.) and relationships between them in a structured form. The paper focuses on the usefulness of ontology in the development of agent-based model for city logistics domain, and attempts to demonstrate the effectiveness of agent technology in analysing the urban freight decision-making processes.

A Combine-Correct-Combine Scheme for Optimizing Dissimilarity-Based Classifiers

Kim, S.-W.,Duin, R.P.W. SPRINGER-VERLAG 2009 Lecture Notes in Computer Science Vol.5856 No.-

Creation of Stepwise Concentration Gradient in Picoliter Droplets for Parallel Reactions of Matrix Metalloproteinase II and IX

Jambovane, Sachin,Kim, Duck Jong,Duin, Evert C.,Kim, Se-Kwon,Hong, Jong Wook American Chemical Society 2011 ANALYTICAL CHEMISTRY - Vol.83 No.9

<P>We present a new methodology for generating a stepwise concentration gradient in a series of microdroplets by using monolithic micro valves that act as “faucets” in micrometer-scale. A distinct concentration gradient of a substrate was generated for the determination of the kinetic parameters of two different enzymes using only 10 picoliter-scale droplets. With a single experiment on a chip, we obtained <I>K</I><SUB>M</SUB> and <I>k</I><SUB>cat</SUB> values of matrix metalloproteinase 2 (MMP-2) and matrix metalloproteinase 9 (MMP-9), and compared the catalytic competence of the two enzymes. The present system and method are highly suitable for applications where the reagents or samples are limited and precious.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancham/2011/ancham.2011.83.issue-9/ac103217p/production/images/medium/ac-2010-03217p_0002.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ac103217p'>ACS Electronic Supporting Info</A></P>

Log-Scale Dose Response of Inhibitors on a Chip

Yun, Jae Young,Jambovane, Sachin,Kim, Se-Kwon,Cho, Sung-Hak,Duin, Evert C.,Hong, Jong Wook American Chemical Society 2011 ANALYTICAL CHEMISTRY - Vol.83 No.16

<P>We demonstrate the accommodation of log-scale concentration gradients of inhibitors on a single microfluidic chip with a semidirect dilution capability of reagents for the determination of the half-inhibitory concentration or IC<SUB>50</SUB>. The chip provides a unique tool for hosting a wide-range of concentration gradient for studies that require an equal distribution of measuring points on a logarithmic scale. Using Matrix metalloproteinase IX and three of its inhibitors, marimastat, batimastat, and CP471474, we evaluated the IC<SUB>50</SUB> of each inhibitor with a single experiment. The present work could be applied to the systematic study of biochemical binding and inhibition processes particularly in the field of mechanistic enzymology and the pharmaceutical industry.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancham/2011/ancham.2011.83.issue-16/ac201177g/production/images/medium/ac-2011-01177g_0002.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/ac201177g'>ACS Electronic Supporting Info</A></P>

다단계 퓨전기법을 이용한 비유사도 기반 식별기의 최적화

김상운(Sang-Woon Kim),로버트 듀인(Robert P. W. Duin) 대한전자공학회 2008 電子工學會論文誌-CI (Computer and Information) Vol.45 No.5

얼굴인식 등과 같은 고차원 식별문제에서는 샘플패턴의 수가 패턴의 차원보다 작아지게 된다. 이러한 상황에서 차원을 축소하기위해 선형판별분석법을 적용할 경우, 희소성(Small Sample Size: SSS)문제가 발생한다. 최근, SSS 문제를 해결하기 위하여 비유사도에 기반 한 식별법(Dissimilarity-Based Classification: DBC)을 이용하는 방법이 검토되었다. DBC에서는 특징벡터 대신에 학습 샘플들로부터 추출한 프로토타입들과의 비유사도를 측정하여 입력 패턴을 식별하는 방법이다. 본 논문에서는 비유사도 표현단계와 DBC 학습단계에서 퓨전기법을 중복 적용하는 다단계 퓨전기법(Multi-level Fusion Strategies: MFS)으로 DBCs를 최적화시키는 방법을 제안한다. 제안 방법을 벤취마크 얼굴영상 데이터베이스를 대상으로 실험한 결과, 식별률을 향상시킬 수 있음을 확인하였다. For high-dimensional classification tasks, such as face recognition, the number of samples is smaller than the dimensionality of the samples. In such cases, a problem encountered in linear discriminant analysis-based methods for dimension reduction is what is known as the small sample size (SSS) problem. Recently, to solve the SSS problem, a way of employing a dissimilarity-based classification(DBC) has been investigated. In DBC, an object is represented based on the dissimilarity measures among representatives extracted from training samples instead of the feature vector itself. In this paper, we propose a new method of optimizing DBCs using multi-level fusion strategies(MFS), in which fusion strategies are employed to represent features as well as to design classifiers. Our experimental results for benchmark face databases demonstrate that the proposed scheme achieves further improved classification accuracies.