• 대한기계학회논문집B
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• 제25권3호
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• pp.442-450
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• 2001

Experiments were carried out on agglomeration of bipolarly charged particles in an alternating current electric field. Laboratory-scale setup was built and experiments were conducted at atmospheric condition. DOS(Di-octyl Sebacate) particles with 100% purity were generated by an atomizer. The particles were branched into two, each of which passed through a wire-to-plate type charging section where a positive or a negative DC high voltage was applied and was charged positively or negatively. These bipolarly charged particles together passed through an agglomeration section where an $\pm$20kV AC power was applied between two plates. The resident time in the agglomeration section was adjusted as l sec. Particle sampling was made by a cascade impactor (MOUDI). The effect of agglomeration system on the reduction ratio of particles below l ㎛ was 42∼45%. Effect of AC frequency on the particle size distribution was found insignificant.

• 임상간호연구
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• 제17권3호
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• pp.443-454
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• 2011

Purpose: The purpose of this study was to investigate the predictors of delirium in patients after orthopedic surgery. Methods: Participants were 121 orthopedic surgery patients from one university affiliated hospital located in Seoul. The instrument of Delirium Observation Screening Scale (DOS) developed by Schuurmans et al. (2003) was utilized. Data were collected from September 1st, 2010 to March 31st, 2011 and analyzed using SPSS 12.0 with descriptive statistics, t-test, chi-square test and logistic regression. Results: The delirium in patients after orthopedic surgery was occurred in 9 (7.4%) out of 121 patients. Several factors were associated with the delirium occurrence age, admission route, preadmission Activity of Daily Living (ADL), preadmission hearing aid use, preadmission walking degree, diagnosis, type of surgery, Intensive Care Unit (ICU) stay after surgery, restraint, drainage tube, time of admission to surgery, preoperative albumin and preoperative sodium. Preadmission ADL, preoperative sodium and time of admission to surgery were the significant predictors of the delirium occurrence. Conclusion: Study results may help nurses predicting and detecting delirium early and providing preventive measures to the patients with high risk of delirium after orthopedic surgery.

• Imaging Science in Dentistry
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• 제49권2호
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• pp.171-176
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• 2019

The available methods for veneer evaluation are limited to clinical and radiographic examinations, which may not allow the appropriate identification of failure. In this report, we demonstrate the use of optical coherence tomography (OCT) as a noninvasive diagnostic and follow-up method to evaluate gingival recovery and the adhesive interface in aesthetic oral rehabilitation involving periodontal plastic surgery and ceramic laminate veneers. OCT was efficient for evaluating both soft and hard tissues, as well as the quality of the adhesive interface. In conclusion, OCT was found to be a promising approach for the professional evaluation of aesthetic oral rehabilitation, as it was capable of generating images that enabled the analysis of gingival recovery and the adhesive interface.

• Coupled systems mechanics
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• 제8권2호
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• pp.129-146
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• 2019

The main goal of this work is to develop a numerical simulator to study an isothermal single-phase two-component flow in a naturally fractured oil reservoir, taking into account advection and diffusion effects. We use the Peng-Robinson equation of state with a volume translation to evaluate the properties of the components, and the discretization of the governing partial differential equations is carried out using the Finite Difference Method, along with implicit and first-order upwind schemes. This process leads to a coupled non-linear algebraic system for the unknowns pressure and molar fractions. After a linearization and the use of an operator splitting, the Conjugate Gradient and Bi-conjugated Gradient Stabilized methods are then used to solve two algebraic subsystems, one for the pressure and another for the molar fraction. We studied the effects of fractures in both the flow field and mass transport, as well as in computing time, and the results show that the fractures affect, as expected, the flow creating a thin preferential path for the mass transport.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제24권6호
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• pp.528-534
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• 2021

Purpose: Living-donor liver transplant emerged as an alternative treatment for end stage liver disease due to the lack of cadaveric organs availability that met the demand. In Portugal, pediatric living-donor liver transplant (P-LDLT) was initiated in 2001 in Portugal in order to compensate for the scarcity of cadaveric organs for such cases. The aim of this study was to retrospectively analyze the morbi-mortality of the 28 donors included in P-LDLT program performed at Coimbra's Pediatric Hospital (CHUC), a Portuguese reference center. Methods: We retrospectively collected pertinent donor data and stratified complications according to Clavien's scoring system. Results: In total, 28.6% (n=8) of the donors had surgical complications. According to Clavien-Dindo's classification, two donors had major complications (Clavien grade ≥3), four donors had grade 2 complications, and two donors had grade 1 complications. There were no P-LDLT-related mortalities in the present case series. The most common verified complications were biliary tract injuries and superficial incisional infections, which are consistent with the complications reported in worldwide series. Conclusion: These patients from CHUC shows that donor hepatectomy in P-LDLT is a safe procedure, with low morbidity and without mortality.

• 한국컴퓨터정보학회논문지
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• 제24권10호
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• pp.41-48
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• 2019

2018년 Cui 등은 생체 정보를 사용하는 three-factor 원격 사용자 인증 프로토콜을 제안하였다. Cui 등은 자신들의 인증 프로토콜이 도청 공격, 스마트카드 분실 공격, 특별히 DoS(denial-of-service) 공격에 안전하다고 주장하였다. 또한 그들은 패스워드 추측 공격, 가장 공격, 그리고 익명성 공격 등에 안전하다고 주장하였다. 그러나 본 논문에서는 Cui 등의 인증 프로토콜을 분석하고, 이 인증 프로토콜이 재생 공격, 내부자 공격, 스마트카드 분실 공격, 그리고 사용자 가장 공격 등에 취약함을 보인다. 게다가 우리는 Cui 등의 인증 프로토콜의 설계 오류도 함께 제시한다.

• 정보보호학회논문지
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• 제13권4호
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• pp.3-11
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• 2003

네트워크 및 호스트의 자원을 낭비하는 DOS(Denial of Service) 및 여러 형태의 연결형/비연결형 공격은 전체 네트워크의 성능을 감소시키므로 공격 호스트를 검출하여 제거하는 일은 매우 중요한 요소이다. 공격 호스트를 검출하기 위한 효율적인 방법 중의 하나가 역추적시스템이나, 지금까지 구현된 역추적 시스템은 라우터의 동작 또는 로그 데이터 저장 및 분석에 따라 오버헤드를 야기 시키는 단점이 있다. 그러므로 본 논문에서는 라우터 및 관리자의 동작을 요구하지 않으며, 많은 양의 로그 데이터를 필요로 하지 않는 역추적 시스템을 제안하고 구현하였다. 구현된 시스템은 역추적 서버와 역추적 에이전트로 구성된다. 서버에서 스니핑과 스푸핑 기법을 이용하여 특정 패킷을 전송하면 각 네트워크에 존재하는 에이전트에서 그 패킷을 검출함으로서 근원지 호스트까지의 연결 경로 정보를 획득하여 역추적 서버로 하여금 공격 호스트를 검출할 수 있도록 한다.

• 정보보호학회논문지
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• 제15권5호
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• pp.115-124
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• 2005

본 논문에서는 모바일 노드(mobile node, MN)와 대응노드(correspondent node, CN)사이의 바인딩 업데이트 (binding update, BU) 프로토콜에 대해 기존 프로토콜들에서 알려진 Redirect 공격과 DOS(denial-of service) 공격을 방지하고 효율성을 향상시키기 위해 새로운 BU 프로토콜을 제안한다. 제안 프로토콜에서 홈 에이전트(home agent, HA)는 BU 메시지의 유효성을 확인하는 인증서버(authentication server)의 기능과 MN과 CN를 위한 세션키 분배센터의 기능을 수행한다. 또한 CGA(cryptographically generated address)를 기반으로 한 stateless Diffie-Hellman 키 합의 기법을 소개하고, 제안 프로토콜의 안전성을 기존 프로토콜과 함께 비교하고 분석한다. 제안 프로토콜은 메시지 수, 계산적 오버헤드 측면에서 기존기법보다 효율적이며, Redirect와 DoS 공격으로부터 안전하다.

• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3849-3854
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• 2022

The present work aims to optimize the radiation protection efficiency for ion-selective containers used in the liquid treatment for the nuclear power plant (NPP) cooling cycle. Some naturally occurring rocks were examined as filler materials to reduce absorbed dose and equivalent dos received from the radioactive waste container. Thus, the absorbed dose and equivalent dose were simulated at a distance of 1 m from the surface of the radioactive waste container using the Monte Carlo simulation. Both absorbed dose and equivalent dose rate are reduced by raising the filler thickness. The total absorbed dose is reduced from 7.66E-20 to 1.03E-20 Gy, and the equivalent dose is rate reduced from 183.81 to 24.63 µSv/h, raising the filler thickness between 0 and 17 cm, respectively. Also, the filler type significantly affects the equivalent dose rate, where the redorded equivalent dose rates are 24.63, 24.08, 27.63, 33.80, and 36.08 µSv/h for natural rocks basalt-1, basalt-2, basalt-sill, limestone, and rhyolite, respectively. The mentioned results show that the natural rocks, especially a thicker thickness (i.e., 17 cm thickness) of natural rocks basalt-1 and basalt-2, significantly reduce the gamma emissions from the radioactive wastes inside the modified container. Moreover, using an outer cementation concrete wall of 15 cm causes an additional decrease in the equivalent dose rate received from the container where the equivalent dose rate dropped to 6.63 µSv/h.

• 이베로아메리카
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• 제11권1호
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• pp.39-70
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• 2009

Este estudo tem por objetivo analisar, do ponto de vista da alquimia, O Alquimia, considerado uma das obras mais representativas do escritor brasileiro Paulo Coelho. Para tanto, começamos a observar as características da alquimia à qual o próprio autor disse que dedicava 11 anos para estudá-la por volta da década de 1970 quando o mundo estava sofrendo grandes mudanças sociais. Desta observação, entendemos que, sendo uma projeção do 'inconsciente' conforme diz C. G. Jung, a essência da alquimia consiste resumidamente nos seguintes conceitos: união de elementos opostos, transformação e salvação. A partir daí, tentamos estudar como esses coneitos estão diluídos na estrutura de O Alquimia e como a experiência do Paulo Coelho com a alquimia interioriza-se no mundo literário dele. E entendemos que os conceitos simbólicos da alquimia e as mensagens que a experiência do escritor com a alquimia configura em suas obras literárias compartilham a quase mesma dimensão semântica. Percebemos também que em alguns aspectos as idéias do escritor consolidadas em torno da sua pesquisa da alquimia vão às vezes além dos conceitos genéricos da alquimia, atingindo assim uma dimensão bastante peculiar e fundamental para compreender melhor o seu universo literário: para ele que se declara católico, Deus não é católico nem islâmico, nem budista, nem hinduista. Por exemplo, ele diz que Deus é um só e é que o Seu nome varia dependendo da religião, porque cada religião precisa escolher um nome para chamá-lo.