• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제10권1호
• /
• pp.61-69
• /
• 2006

단 한 번의 인증으로 여러 시스템을 자유롭게 사용할 수 있는 SSO(Single Sign-On)기술은 단일 인증이라는 편이성과 최근 PKI기반의 강력한 보안 기능까지 갖추게 되어 기업에게 주목 받는 대상이 되었다. 최근에는 SSO기술을 기반으로 한 EAM이라는 권한관리 시스템이 등장하여 현재의 기업 IT 인프라 시스템의 효율성과 안정성을 증대시켰다. 본 논문에서는 SSO 기본 개념과 기존 SSO시스템의 특징을 분석하고, 다중 순환자를 통해 인증시 부하를 분산시킨 PKI 기반의 SSO 모델을 제안한다.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2012년도 추계학술발표대회
• /
• pp.877-880
• /
• 2012

정보통신기술의 발전으로 기업의 내에서만 업무를 하던 시대에서 벗어나 언제 어디서나 손쉽게 업무를 수행할 수 있는 스마트워크 환경이 가능하게 되었다. 특히 모바일 디바이스의 성능 발전과 급속한 보급은 스마트워크를 이용하는 환경이 다양해지는 계기가 되었고 이로 인해 동일한 사용자라 할지라도 스마트워크에 접근하는 방법이나 환경이 동적으로 변경 될 수 있다. 이러한 특성은 보안 위협의 유형도 다양하게 하여 기업 내부의 정보를 보호하기 어렵게 만들었다. 이로 인해 기존의 사용자 정보 중심의 통합 인증 관리시스템인 EAM(Extranet Access Management)만으로 다양한 위협에 대응하기에는 부족하게 되었다. 이에 본 논문에서는 기존 EAM 시스템의 한계를 알아보고 스마트워크 환경에서 사용자 정보 외에 디바이스, 네트워크, 위치 정보를 활용하여 접근 시의 환경에 따라 사용자의 권한도 동적으로 생성하는 방식을 제안한다.

• Composites Research
• /
• 제24권3호
• /
• pp.17-24
• /
• 2011

Ag/Cu층에서 발생하는 misfit 전위를 분석하기 위하여, EAM기법을 활용한 나노인덴테이션 해석을 수행하였다. N$\'{o}$se-Hoover 서모스텟 조건에 의거하여, 2-5nm 정도의 두께를 갖는 필름층에 구형 인덴터로 압입하였다. 해석결과는 misfit 전위에 대한 상대적인 압입위치가, 4nm이하의 필름에 대하여 영향을 미치는 것으로 나타났다. 전위에 의한 슬립 발생할 때 탄성에너지 변화는 Ag/Cu의 연화의 중요한 변수로 작용하며, 각각의 경우에 대하여 임계필름두께에 대해서도 고찰하였다.

• Communications for Statistical Applications and Methods
• /
• 제17권3호
• /
• pp.367-376
• /
• 2010

최근 확산모형의 추정을 위한 매우 다양한 방법론들이 제시되고 연구 되어 왔다. 본 연구에서는 제안된 확산모형의 추정 방법 중에서, 안장점근사법을 이용한 확산모형의 모수 추정방법에 대하여 살펴보게 되고, 가장 단순한 형태의 안장점근사법인 단일항 안장점근사법의 사용을 제안하게 된다. 단일항 안장점근사법은 오일러근사법과 마찬가지로 계산속도가 빠르고, 다양한 모형에 적용이 가능하면서도 최대우도추정량과 마찬가지로 성능이 우수한 특성을 갖고 있음을 살펴보게 된다. OU 확산모형을 대상으로 한 시뮬레이션 연구를 통하여 단일항 안장점근사를 이용한 추정량과 다른 추정량들과의 성질을 비교한다.

• 대한금속재료학회지
• /
• 제49권6호
• /
• pp.425-439
• /
• 2011

A review of the development history of interatomic potential models for ionic materials was carried out paying attention to the way of future development of an interatomic potential model that can cover ionic, covalent and metallic bonding materials simultaneously. Earlier pair potential models based on fixed point charges with and without considering the electronic polarization effect were found to satisfactorily describe the fundamental physical properties of crystalline oxides (Ti oxides, $SiO_2$, for example) and their polymorphs, However, pair potential models are limited in dealing with pure elements such as Ti or Si. Another limitation of the fixed point charge model is that it cannot describe the charge variation on individual atoms depending on the local atomic environment. Those limitations lead to the development of many-body potential models(EAM or Tersoff), a charge equilibration (Qeq) model, and a combination of a many-body potential model and the Qeq model. EAM+Qeq can be applied to metal oxides, while Tersoff+Qeq can be applied to Si oxides. As a means to describe reactions between Si oxides and metallic elements, the combination of 2NN MEAM that can describe both covalent and metallic elements and the Qeq model is proposed.

• ETRI Journal
• /
• 제45권1호
• /
• pp.163-170
• /
• 2023

We report an electroabsorption modulator (EAM)-integrated distributed Bragg reflector laser diode (DBR-LD) capable of supporting a high data rate and a wide wavelength tuning. The DBR-LD contains two tuning elements, plasma and heater tunings, both of which are implemented in the DBR section, which have blue-shift and red-shift in the Bragg wavelength through a current injection, respectively. The light created from the DBR-LD is intensity-modulated through the EAM voltage, which is integrated monolithically with the DBRLD using a butt-joint coupling method. The fabricated chip shows a threshold current of approximately 8 mA, tuning range of greater than 30 nm, and static extinction ratio of higher than 20 dB while maintaining a side mode suppression ratio of greater than 40 dB under a window of 1550 nm. To evaluate its modulation properties, the chip was bonded onto a mount including a radiofrequency line and a load resistor showing clear eye openings at data rates of 25 Gb/s nonreturn-to-zero and 50 Gb/s pulse amplitude modulation 4-level, respectively.

• 대한방사선기술학회지:방사선기술과학
• /
• 제45권6호
• /
• pp.483-489
• /
• 2022

This study proposes a new skull lateral examination, and provides an improved examination environment for patients and radiologists. The study was divided into three groups. One group was divided into the SID (source to image receptor distance) 110 ㎝ and 180 ㎝ in the skull lateral posture, the other group The other group was divided into an position in contact with the detector and an position without contact with the detector, and the other group was divided into male and female groups, considering that the difference in shoulder width between adult males and females would affect the dose and image quality. For dose evaluation, the ESD (entrance surface dose) was measured at the EAM (external auditory meatus), and the conditions were applied equally at 70 ㎸p, 200 ㎃, and 10 ㎃s. For image quality evaluation, SNR (signal to noise ratio) and CNR (contrast to noise ratio) were measured in frontal sinus, EAM, and sella turcica. As a result of ESD comparison, when sid 110 ㎝ to sid 180 ㎝ was changed among the three groups, ESD values decreased the most to 729.18±4.62 μ㏉ and 224.18±0.74 μ㏉ at 180 ㎝ (p<0.01). The values of SNR and CNR were statistically significant (p<0.01), but there was no qualitative difference. This shows that when the SID is 180 ㎝, it is possible to reduce the dose without lowering the image quality. So, It is suggested that the SID 180 ㎝ is used without contacting the detector when examining the skull lateral.

• Journal of Pharmaceutical Investigation
• /
• 제10권4호
• /
• pp.23-29
• /
• 1980

Ampicillin-polyvinylpyrrolidone coprcipitates, 1 : 5 ratio w/w, were prepared by the solvent method to increase the solubility and dissolution rate of ampicillin anhydrous. It was found that the solubility and dissolution rate of the coprecipitate were higher than that of ampicillin anhydrous, mechanical mixture of ampicillin and polyvinylpyrrolidone in powder state. The intrinsic, dissolution rate, G, are $1.15{\times}10^{-4}\;mole\;cm^{-2}\;min^{-1}$ for the coprecipitate, $1.09{\times}10^{-5}\;mole\;cm^{-2}\;min^{-1}$ for ampicillin anhydrous, and the activation energy of the coprecipitate and ampicillin anhydrous are $9.091{\times}10^3cal/mole$ and $1.854{\times}10^3cal/mole$, respectively.

• Journal of the Optical Society of Korea
• /
• 제19권4호
• /
• pp.371-375
• /
• 2015

The impact of equivalent optical bandwidth on the performance of a system using a reflective electroabsorption modulator (R-EAM) based optical source has been experimentally evaluated with signals operating at 2.5 Gb/s and beyond. The equivalent optical bandwidth of our source with a broadband seed light was simply adjusted by using a bandwidth tunable optical filter. From the measurements, we have estimated the required equivalent optical bandwidth of our source for an error-free transmission (@ bit-error-rate of $10^{-12}$) and a forward error correction (FEC) threshold of $2{\times}10^{-4}$.

• 한국진공학회지
• /
• 제4권S2호
• /
• pp.139-147
• /
• 1995

The mechanism of the ionized cluster beam deposition has been studied using Molecular Dynamics Simulation. The Embedded Atom Method(EAM) potential were used in the simulation. The impact of a Au95-cluster on Au(100) substrate was studied for the impact energies 0.15-10eV/atom. The dependency of the impact energy of cluster beam was observed. For the cluster energy impact of 10eV per atom, the defects on surface were created and the cluster embedded into substrate as an amorphous state. For the energy of 0.5eV per atom, the defect free homoepitaxial growth was observed and atomic scale nucleation was formated, which are in good agreement with experiment. Thus molecular dynamics simulation is very useful to study the mechanism of the ionized cluster beam deposition.