• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.376-378
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• 2004

인터넷의 사용이 날로 증가함에 따라 전자상거래가 인터넷을 통해 활발하게 이루어지는데 있어서 금융권 및 각종 기타 기관에서는 인증서 기반의 전자서명을 사용하고 있다. 이러한 인증서 기반의 시스템은 궁극적으로 SSO(Single Sign-On)를 지향하는데, 동일 인증기관 내의 모든 서비스는 단 한 번의 접속으로 모두 사용할 수 있게 하는 것이 그 목적이다. 그러나 SSO는 동일 인증기관이라는 제약사항이 따르기 때문에 인터넷을 이용하는 사용자들이 각 인증기관별로 인증서를 따로 관리하게 되는 불편함이 생기게 된다. 따라서 본 논문에서는 OASIS에서 발표한 SAML을 이용하여 다른 이질적인 인증기관간의 인증을 통합 할 수 있는 방법을 제시하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05c
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• pp.2181-2184
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• 2003

전자상거래, Single Sign On, 전자문서교환 등 웹 기반의 사이버 교환이 급증하는 오늘날 상대방의 신뢰를 보증해 줄 수 있는 수단으로 인증서의 사용이 필수적이다. 인증서는 인증기관을 신뢰한다는 가정에서 사용되기 때문에 통신개체 사이에서 보다 정확한 인증이 필요하다. 본 논문에서는 공개키 기반구조에서 인증서를 사용하는 모든 암호시스템 분야에 응용될 수 있는 인증 및 키 복구 메커니즘을 설계하였다. 서버와 사용자간에 인증서를 기반으로 공개키 암호에 의한 인증과 세션 암호 키 분배, 그리고 응용 자원서버들과의 비밀통신에서 암호 키의 유실을 고려한 키 복구 지원 프로토콜을 제안하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.400-402
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• 2004

EAM(Enterprise Access Management)은 SSO(Single Sign On)와 사용자 역할기반의 세분화된 접근관리를 제공하는 적극적 시스템 인증, 제어관리 솔루션으로 EAM 도입을 위해서는 중요한 자원들의 안전한 보관 관리가 필수적이다. 이를 위해 각 기업이나 그룹에서는 XML을 기반으로 한 여러 보안기술을 도입하고 있지만 현재 XML 정보 보안 기술을 중심으로 한 EAM시스템의 구현은 그 기반이 미미한 실정이며 표준에 따른 시스템의 고려도 미약한 실정이다. 특히 XML 정보보호기술과 기존 보안기술인 공개키 기반구조(Public Hey infrastructure, PKI), 권한관리구조 PMI(Privilege Management infrastructure)등과 같은 인증기술과의 상호연동기술에 관한 연구가 부족한 상태이다 이에 본 논문은 표준 XML 정보 보호기술 중 대표적인 기술인 XACML(extensible Access Control Markup Language)과 PMI를 연동한 안전한 EAM 통합 접근 시스템 구축 방안에 대친 연구하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.1253-1256
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• 2004

기존의 기업환경에서의 싱글사인온은 비싼 구현과 높은 관리 비용, 확장성의 제약성 등의 단점이 있었으며, 특히 보안을 떨어뜨릴 수 있는 요인이 될 수 있었으나, 최근 새로운 기술들의 등장과 인프라 및 인증 관리 인식의 발전으로 현재의 싱글사인온은 기업에게 주목 받는 대상이 되었다. 본 논문에서는 지금까지 발표된 싱글사인온의 아키텍쳐 및 통합모델들을 나열하고 기업의 환경에 적절한 모델을 선택하는 지침을 제시한다.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.39
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• pp.1.1-1.7
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• 2017

Background: Multiple myeloma (MM) is characterized by a neoplastic proliferation of plasma cells primarily in the bone marrow. Bisphosphonates (BP) are used as supportive therapy in the management of MM. This study aimed to analyze the incidence, risk factors, and clinical outcomes of medication-related necrosis of the jaw (MRONJ) in MM patients. Methods: One hundred thirty MM patients who had previous dental evaluations were retrospectively reviewed. Based on several findings, we applied the staging and treatment strategies on MRONJ. We analyzed gender, age, type of BP, incidence, and local etiological factors and assessed the relationship between these factors and the clinical findings at the first oral examination. Results: MRONJ was found in nine male patients (6.9%). The mean patient age was 62.2 years. The median BP administration time was 19 months. Seven patients were treated with a combination of IV zoledronate and pamidronate, and two patients received single-agent therapy. The lesions were predominantly located in the mandible (n = 8), and the most common predisposing dental factor was a history of prior extraction (n = 6). Half of the MRONJ were related to diseases found on the initial dental screen. Patients with MRONJ were treated with infection control and antibiotic therapy. When comparing between the MRONJ stage and each factor (sign, location, etiologic factor, BP type, treatment, and outcome), there were no significant differences between stages, except for between the stage and sign (with or without purulence). Conclusions: For prevention of MRONJ, we recommend routine dental examinations and treatment prior to starting BP therapy.

• Bulletin of the Korean Chemical Society
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• v.29 no.6
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• pp.1195-1198
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• 2008

Kinetic studies of the additions of benzylamines to a noncyclic dicarbonyl group activated olefin, methyl $\alpha$-acetyl-$\beta$ -phenylacrylates (MAP), in acetonitrile at 30.0 ${^{\circ}C}$ are reported. The rates are lower than those for the cyclic dicarbonyl group activated olefins. The addition occurs in a single step with concurrent formation of the $C_\alpha$ -N and $C_\beta$ -H bonds through a four-center hydrogen bonded transition state. The kinetic isotope effects ($k_H/k_D$ > 1.0) measured with deuterated benzylamines ($XC_6H_4CH_2ND_2$) increase with a stronger electron acceptor substituent ($\delta\sigma$ X > 0) which is the same trend as those found for other dicarbonyl group activated series (1-4). The sign and magnitude of the cross-interaction constant, ρXY, is comparable to those for the normal bond formation processes in the $S_N2$ and addition reactions. The relatively low ${\Delta}H^\neq$ and large negative ${\Delta}S^\neq$ values are also consistent with the mechanism proposed.

• Bulletin of the Korean Chemical Society
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• v.23 no.10
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• pp.1459-1462
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• 2002

The kinetics of the addition of X-substituted benzylamines (BA) to Y-substituted Benzylideneacetylacetones (BAA) have been investigated in acetonitrile at $25.0^{\circ}C$. The reaction is studied under pseudo-first-order conditions by keeping a large excess of BA over BAA. The addition of BA to BAA occurs in a single step in which the addition of BA to $C_\alpha$ of BAA and proton transfer from BA to $C_\beta$ of BAA take place concurrently with a four-membered cyclic transition state structure. The magnitude of the Hammett ($p_X$) and Bronsted ($\beta_x$) coefficients are rather small suggesting an early tansition state (TS). The sign and magnitude of the cross-interaction constant, $p_{XY}$ (= -0.49), is comparatible to those found in the normal bond formation processes in the $S_N2$ and addition reactions. The normal kinetic isotope effect ($K_H/K_D$ > 1.0) and relatively low $\Delta$H^{${\neq}$}$ and large negative $\Delta$S^{${\neq}$}$ values are also consistent with the mechanism proposed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.1
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• pp.9-16
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• 2020

The objective of this study is to propose closed-form solutions to the free vibration response of single-degree-of-freedom (SDOF) systems, as part of fundamental research on dynamic systems with Coulomb friction. The motion of a dynamic system with Coulomb friction is described by a nonlinear differential equation, and, due to the variation in the sign of friction force term with the direction of motion, it is difficult to obtain the closed-form solution. To solve this problem, the nonlinear differential equation is directly computed by numerical integration, or an approximated solution is indirectly obtained using a linear differential equation wherein the damping effect due to Coulomb friction is replaced by an equivalent viscous damping term. However, these conventional methods do not provide a closed-form solution from a mathematical point of view. In this regard, closed-form solutions to the free vibration response of SDOF systems with Coulomb friction are derived herein by considering that the sign of the friction force term is reversed in each half-cycle of motion and by expanding it to the entire time history using the power series function. In addition, for a given initial condition, both the number of free vibration half-cycles and the response at the instant when free vibration motion stops are predicted under the condition that the motion of free vibration is stopped when the amplitude of the friction force is higher than that of the restoring force due to stiffness.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.24 no.2
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• pp.135-144
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• 2021

Purpose: Although ultrasonography is the gold standard of diagnosing intussusception, plain abdomen radiograph (AXR) is often used to make differential diagnosis for pediatric patients with abdominal pain. In intussusception patients, we aimed to analyze the AXR and clinical data to determine the characteristics of early AXR findings associated with diagnosis of intussusception and recurrence after reduction. Methods: Between January 2011 and June 2018, 446 patients diagnosed with intussusception based on International Classification of Diseases-10 code of K56.1 were admitted. We retrospectively reviewed medical records of 398 patients who received air reduction; 51 of them have recurred after initial reduction. We evaluated six AXR features including absent ascending colon gas, absent transverse colon gas, target sign, meniscus sign, mass, and ileus. Clinical data and AXR features were compared between single episode and recurrence groups. Results: Two groups did not show significant differences regarding clinical data. Mean time to recurrence from air reduction was 3.4±3.2 days. Absent ascending colon gas (63.9%) was the most common feature in intussusception, followed by mass (29.1%). All of six AXR features were observed more frequently in the recurrence group. Absent transverse colon gas was the most closely associated AXR finding for recurrence (odds ratio, 2.964; 95% confidence interval, 1.327-6.618; p=0.008). Conclusion: In our study, absence of ascending colon gas was the most frequently seen AXR factor in intussusception patients. Extended and careful observation after reduction may be beneficial if such finding on AXR is found in intussusception patients.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.163-168
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• 2003

Analytical approach is applied to predict temperature of satellite box under worst hot condition from fairing jettison to separation. The box is tried to solve analytically which is exposed to known environmental heating condition and has internal heating and irradiation to space. For a single thermal mass, governing equation for temperature is simplified to 1st order ordinary differential equation(ODE) by several assumptions. Two cases are considered. The one is for constant mass box and the other is for mass-varying box. Each case has three different analytical solution by sign of constant term in ODE. One analytical solution for constant mass is applied to physical launch stage condition. It is concluded that the present analytical method can be used to quick predict the temperature of a satellite box and check whether a satellite is safe against space environment during launch stage.