• Annual Conference of KIPS
• /
• 2008.11a
• /
• pp.1513-1516
• /
• 2008

이동 에이전트는 기존의 클라이언트-서버 환경을 대체하는 분산 컴퓨팅 패러다임이다. 특히 이동 에이전트는 목표를 달성할 때까지 스스로 인터넷 환경을 떠돌며 정보를 수집하고 분석할 수 있도록 설계할 수 있다. 하지만 이동 에이전트가 문제없이 활동하기에 인터넷은 개방적인 환경이며, 많은 경우에 있어 이동 에이전트는 여러 적대적인 호스트들과 접할 수 있다. 이로 인해 이동 에이전트가 안전하게 인터넷상에서 이주 하도록 만드는 것이 큰 관건이 되고 있다. 최근 Volker와 Mehrdad가 이동 에이전트 환경에 있어서 효율적인 접근 제어와 키 관리 메커니즘을 제안하였다. 하지만 이 기법은 이동 에이전트의 이주 대상을 한정시키고, 이주 대상이 많아질수록 키를 관리하는 구조가 커지는 문제점이 있다. 본 논문에서는 이동 에이전트에 역할 모델을 적용함으로써 키 관리에 있어서 그 크기를 줄이고, 인증 센터를 사용하여 이동 에이전트의 이주 대상 호스트를 미리 한정짓지 않도록 하여 이동 에이전트가 자유롭게 이주할 수 있는 접근제어 기법을 제안한다. 본 기법을 이동 에이전트에 적용하면 에이전트의 크기를 줄이고, 이동할 수 있는 호스트의 제약을 줄일 수 있다.

• Analytical Science and Technology
• /
• v.36 no.6
• /
• pp.281-290
• /
• 2023

Zidovudine is an antiretroviral agent prescribed for the prevention and treatment of human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS). It is typically recommended to be used in combination with other antiretroviral drugs. Zidovudine has the potential to generate N-nitrosodimethylamine (NDMA) in the presence of dimethylamine and nitrite salt under acidic reaction conditions during the drug manufacturing process. NDMA is a potent human carcinogen that may be detected in drug substances or drug products. An analytical method was developed to determine NDMA in pharmaceuticals including zidovudine using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The analysis involved reversed-phase chromatography on a Kinetex F5 column with a mobile phase comprising water-acetonitrile mixtures. The detection of positively charged ions was conducted using atmospheric pressure chemical ionization (APCI). The calibration curve demonstrated excellent linearity (r = 0.9997) across the range of 1-50 ng/mL with a highly sensitive limit of detection (LOD) at 0.3 ng/mL. The developed method underwent thorough validation for specificity, linearity, accuracy, precision, robustness, and system suitability. This sensitive and specific analytical method was applied for detecting NDMA in zidovudine drug substance and its formulation currently available in the market, indicating its suitability for drug quality management purposes.

• Annual Conference of KIPS
• /
• 2007.11a
• /
• pp.640-643
• /
• 2007

기업 네트워크에 대한 보안 위협이 지속적으로 발생함에 따라 네트워크 관리가 중요시 되고 있다. 기업 네트워크의 보안성을 강화하기 위해서는 네트워크상의 각 노드에 설치된 보안 소프트웨어나 취약성이 있는 소프트웨어의 업데이트가 요구된다. 그러나, 일반적인 서버/클라이언트 형태의 소프트웨어 업데이트 서비스는 서버의 부하가 크고 시간효율적이지 못하다. 따라서 본 논문에서는 네트워크의 논리적인 형태를 노드의 상태정보에 따라 바이노미얼 트리로 구성하고, 이를 기반으로 이동 에이전트가 각 노드를 순회하며 소프트웨어를 업데이트할 수 있는 시스템을 제안한다. 제안 시스템을 이용함으로써 서버에 집중되는 부하를 줄이면서 빠른 시간 내에 네트워크 상의 모든 노드의 소프트웨어를 업데이트 할 수 있게 된다.

• Annual Conference of KIPS
• /
• 2007.05a
• /
• pp.1163-1166
• /
• 2007

핸드오버가 발생하는 이동망 환경에서 주요 이슈 중 하나는 핸드오버 후 MN(Mobile Node)의 트래픽이 전송될 새로운 경로 상에 자원 재예약을 위한 지연 시간을 최소화하는 것이다. 이를 위해, 데이터 전달 경로가 변경된 경로에서만 자원예약 시그널링이 이루어지도록 CRN(Crossover Node)을 발견하는 것이 중요하다. 이동망 환경에서 자원 재예약을 위한 CRN은 SID(Session ID)를 이용하여 발견될 수 있다. 그러나 HMIPv6 네트워크에서 MAP(Mobility Anchor Point)과 HA(Home Agent)간 군집(Aggregate) 자원 예약이 이루어진 경우에서는 SID를 이용하여 CRN을 발견할 수 없다. 왜냐하면, MN의 핸드오버 후, 종단간 SID는 동일할지라도 이전 MAP과 HA간 설립된 세션의 군집 SID가 새로운 MAP과 HA간 설립된 세션의 군집 SID와 다르기 때문이다. 이에, 본 논문에서는 HMIPv6 네트워크에서의 CRN 발견방안을 제안한다. 제안하는 방안에서는 시그널링 메시지에 이전 군집 세션 정보를 포함하여 전달함으로서 시그널링 메시지가 목적지까지 도달하기 전에 CRN이 발견될 수 있도록 하였다. 제안하는 방안은 군집 자원예약이 갖는 시그널링 및 플로우별 상태 정보 감소 효과를 그대로 유지하면서, MN의 핸드오버 후, 자원 재예약을 위한 지연 시간을 단축시킴으로서 통신 성능을 향상 시킬 수 있을 것으로 기대된다.

• Korean Chemical Engineering Research
• /
• v.49 no.6
• /
• pp.829-834
• /
• 2011

Lysozyme in egg white functions as bacteriolysis agent and ovalbumin plays a role as antigen in immune system. Egg white analysis methods usually include electrophoresis, gel permeation chromatography and reversed-phase HPLC(RP-HPLC). Among them, RP-HPLC was selected for rapid analysis and C18 column(Agilent, USA) was used as HPLC column. Optimum conditions were searched by changing mobile phase and temperature. Capacity factor and resolution were calculated and compared for various elution conditions. In the isocratic elution, mobile phase volume ratio was changed from 30/70/0.1 to 60/40/0.1(Acetonitrile(ACN)/Distilled water(DW)/Trifluoroacetic acid(TFA)). ACN composition was increased by 10% and temperature was set as $20^{\circ}C$. In the gradient elution, ACN/DW ratio was changed from 10/90 to 60/40 during 20 minute and temperature was varied as 20, 30 and $40^{\circ}C$. In the isocratic elution, three peaks were separated at 50/50/0.1. Lysozyme and ovalbumin were confirmed as first and third peak in three peaks respectively. In the gradient elution, four peaks were separated at $30^{\circ}C$. Lysozyme and ovalbumin were confirmed as first peak and third peak in four peaks respectively.

• The KIPS Transactions:PartC
• /
• v.9C no.2
• /
• pp.293-296
• /
• 2002

UP Link is One of the commercial product which converts HTML to HDML convertor in order to show the internet www contents in the mobile environments. When UP browser accesses HTML pages, the agent in the UP Link controls the converter to change the HTML to the HDML, I-Mode, which is developed by NTT-Docomo of Japan, has many contents through the long and stable commercial service. Micro Explorer, which is developed by Stinger project, also has many additional function. In this paper, we designed and implemented WAP convertor which can accept C-HTML contents and mHTML contents. C-HTML format by I-Mode is a subset of HTML format, mHTML format by ME is similar to C-HTML, So the content provides can easily develop C-HTML contents compared with WAP and the other case. Since C-HTML, mHTML and WML are used under the mobile environment, the limited transmission capacity of one page is also similar. In order to make a match table. After that, we apply conversion algorithm on it. If we can not find matched element, we arrange some tags which only can be supported by WML to display in the best shape. By the result, we can convert over 90% contents.

• Journal of Society of Preventive Korean Medicine
• /
• v.4 no.2
• /
• pp.235-241
• /
• 2000

This study was carried out to evaluate cytotoxic effects of Poncirus trifoliata Raf. extract on lymphocytic leukemia tumor (L1210) cell lines. Disruptions in cell organelles were determined by 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl-2H-tetrazoliumbromide (MTT) assay The comparison of Ic50 Values of Poncirus trifoliata Raf. extract in L1210 cell lines showed that their susceptibility to these fractons decreased in the following order: adriamycin > Fr.4> Fr. 6> Fr. 5> Fr. 3> Fr. 1> Fr. 2 by the MTT assay. In order to develop an antumicrobial agent, Poncirus trifoliata Raf. was extracted wit ethanol, and then it was fractionated with several mobile phase. The antitumor activities of fractions of the ethanol soluble extract was investigated. The minimal inhibitory concentrations (MIC) of fractions of the ethanol soluble extract of Poncirus trifoliata Raf. against microorganisms were also examined. Antimicrobial activities of ampicillin and ketoconazole as references were compared to those of fractions of the ethanol soluble extract of Poncirus trifoliata Raf. The antimicrobial activities of all fractions from the extract had growth inhibition activities against gram-positive bacteria, gram-negative bacteria and fungi $(MIC\;>\;200{\mu}g/ml)$. These results suggest that fraction 4 of the ethanol soluble extract of Poncirus trifoliata Raf. possessed the most antitumorous agent.

• Journal of Internet Computing and Services
• /
• v.12 no.4
• /
• pp.135-143
• /
• 2011

The smartphone allows learners to be involved in learning environments in which students actively study from anywhere and at anytime. Because learners can keep engaged in the environment where they can access to the internet, they can efficiently study in transit using various features and functions of smartphone. Smart learning is a unique learning based on mobility and functions of mobile digital devices including searching and sharing information and using various applications. For the effective use of smartphones in e-learning systems, the contents and learning management systems should be designed to meet effective teaching and learning principles, such as interactivity and collaborations. In smart learning, learning contents for effective learning need to be integrated with typical functions of smartphones and to develop small pieces of learning contents according to learning topics. In the case of learning management systems, it should reflect understanding of learners' environment using a PA agent program and provide personalized learning services.

• Knowledge Management Research
• /
• v.21 no.1
• /
• pp.175-195
• /
• 2020

The development of platform service based on the information and communication technology has revolutionized patterns of commercial transactions, driving the growth of global economy. Furthermore, the radical advancement of artificial intelligence(AI) presents the huge potential to innovate almost all the industrial and economic activities. Given these technological developments, the goal of this paper is to investigate AI's impact on the platform service innovation as well as its influence on the business performance. For the goal, this paper presents the review of the types of service innovation, the nature of platform services, and technological characteristics of leading AI technologies, such as chatbot and recommendation system. As an empirical study, this paper performs a multiple case study of Kakao Group which is the leading mobile platform service with the most advanced AI in Korea. To understand the role and effect of AI on Kakao platform service, this study investigated three cases, including chatbot agent of Kakao Bank, Smart Call service of Kakao Taxi, and music recommendation system of Kakao Mellon. The analysis results of the case study show that AI initiated innovations in platform service concepts, service delivery, and customer interface, all of which lead to a significant decrease in the transaction costs and the personalization of services. Finally, for the successful development of AI, this research emphasizes the significance of the accumulation of customer and operational data, the AI human capital, and the design of R&D organization.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.3
• /
• pp.1479-1487
• /
• 2011

In the field of the entire electronic component industry including mobile IT products, the importance of a versatile package with the multifunctional or high capacity memories is gradually increased. Multi Chip Package which has several chips in a single package is frequently used for that purpose. In MCP, epoxy adhesive films play a major role in adhesion between the chips or between chip and substrate. A series of silane coupling agents with a functional group such as epoxy, amine, mercaptan, and isocyanate were applied to the epoxy adhesives and material properties such as wettability and reliability of the adhesives were investigated. From the results, the silane coupling agent with an epoxy functional group showed highest wettability and peel strength in epoxy adhesive. For those reasons, it lead to a superior reliability in the epoxy adhesive against interfacial fracture behaviors through moisture resistance test.