• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.36 no.7
• /
• pp.695-702
• /
• 2008

Flow instability in the rocket turbo pump systems can be caused by various elements such as valve, orifice and venturi and etc. The formation of cavitation specially in the propellant feeding system can trigger the mass flow and pressure oscillation due to cyclic formation and depletion of cavitations. If the cryogenic propellant are used, which is very sensitive to temperature variation, the change of propellant properties due to thermodynamic effect should be accounted for in the flow analysis. This study focuses on the formation of cryogenic cavitation adopting MUSHY IDM model suggested by Shyy and coworkers. Also, the flow instability is investigated with developed numerical code in the downstream of orifice flow. To this end, three different orifices are selected and investigated by the numerical calculation.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2014.11a
• /
• pp.516-519
• /
• 2014

Cloud computing is an up-and-coming paradigm shift transforming computing models from a technology to a utility. However, security concerns related to privacy, confidentiality and trust are among the issues that threaten the wide deployment of cloud computing. With the advancement of ubiquitous mobile-based clients, the ubiquity of the model suggests a higher integration in our day to day life and this leads to a rise in security issues. To strengthen the access control of cloud resources, most organizations are acquiring Identity Management Systems (IDM). This paper presents one of the most popular IDM systems, specifically OAuth, working in the scope of Mobile Cloud Computing which has many weaknesses in its protocol flow. OAuth is a Delegated Authorization protocol, and not an Authentication protocol and this is where the problem lies. This could lead to very poor security decisions around authentication when the basic OAuth flow is adhered to. OAuth provides an access token to a client, so that it can access a protected resource, based on the permission of the resource owner. Many researchers have opted to implement OpenlD alongside OAuth so as to solve this problem. But OpenlD similarly has several security flows. This paper presents scenarios of how insecure implementations of OAuth can be abused maliciously. We incorporate an authentication protocol to verify the identities before authorization is carried out.

• International Journal of Railway
• /
• v.8 no.1
• /
• pp.5-9
• /
• 2015

Reliability based limit state design method is replacing traditional deterministic designs such as allowable stress design and/or ultimate strength design methods in world trends. European design code(Eurocode) has adopted limit state design, and Korea road bridge design standard has also recently been transferred to limit state design method. In this trend, Korea railroad design standard is also preparing for adopting the same design concept. While safety factors are determined empirically in traditional design, load combinations as well as load factors are determined by solving limit state equations. General partial safety factors are evaluated by using AFORM(Advanced First Order Reliability Method) in the reliability based limit state design method. In this study sensitivity analysis is carried out for a dead load factor and a live load factor. Relative precisions of the dead load and the live load factors are discussed prior to the AFORM analysis. Furthermore the sectional forces of design and the material quantities required by two different design methods are compared for a PSC box girder railway bridge.

• Electronics and Telecommunications Trends
• /
• v.22 no.4 s.106
• /
• pp.144-155
• /
• 2007

본 논문에서는 웹 환경에서 개인정보를 안전하게 관리할 수 있는 기술을 소개한다. 프라이버시와 관련된 기술을 분류하고, 웹 환경에서 적용될 수 있는 정책 기반 프라이버시 기술인 P3P, EPAL, XACML을 설명한다. 또한 이 기술을 활용한 마이크로소프트 인터넷 익스플로러의 P3P 기능, AT&T의 웹 브라우저용 P3P 사용자 에이전트 privacy bird, 그리고 identity 관리 시스템 환경에서 XACML을 이용한 ETRI IDMS의 privacy controller에 대하여 자세히 기술한다. 그리고 상기 기술의 장단점을 비교하여 향후 해결해야 할 점을 고찰한다.

• Defense and Technology
• /
• no.11 s.297
• /
• pp.56-61
• /
• 2003

Longbow Apache의 밀리미터파 사통 레이더는 최첨단의 광학 체계조차 장님으로 만드는 연기와 날씨도 침투한다. 애초에 특수 작전용 Black Hawk와 Chinook에 탑재된 통합 RF Countermeasures는 대공 레이더를 식별하고 위치확인 후 교란한다. IDM(Improved Data Modem), 내장된 GPS 관성 항법장치 그리고 초지평선 HF 무전기가 헬기편대에 포함되서 미래전투체계(FCS)와 UAV(Unmanned Aerial Vehicle)의 정보를 실시간으로 이용할 수 있게 한다. 게다가 AWACS와 JSTARS같은 공군의 공중 레이더, 혹은 해군의 네트워크 중심의 전장 공간 같은 데 있는 해상 센서를 통해 전체적으로 파악된 영상까지도 가능하게 될 것이다.

• Proceedings of the IEEK Conference
• /
• 2003.11b
• /
• pp.211-214
• /
• 2003

In this paper, we intend to find user's TV program choosing pattern and, recommend programs that he/she wants. So we suggest item dependency map which express relation between chosen program. Using an algorithm that we suggest, we can recommend an program, which a user has not saw yet but maybe is likely to interested in. Item dependency map is used as patterns for association in hopfield network so we can extract users global program choosing pattern only using users partial information. Hopfield network can extract global information from sub-information. Our algorithm can predict user's inclination and recommend an user necessary information.

• Review of KIISC
• /
• v.21 no.4
• /
• pp.40-46
• /
• 2011

인터넷상에서 무분별한 주민등록번호 사용을 최소화하여 명의도용 등의 피해를 방지하기 위하여 2005년부터 아이핀을 개발하여 보급중이며, 특히 아이핀 서비스를 대폭 개선한 아이핀 2.0이후에는 도입하는 웹사이트와 이용자가 급증하는 상황이다. 본 논문에서는 아이핀이 단순히 웹사이트 회원가입시 실명확인을 대체하는 수단을 넘어 인터넷상에서 국민 전체가 안전하고 편리하게 사용할 수 있는 디지털 ID가 되기 위한 발전 전략을 제시하고자 한다.

• Journal of Acupuncture Research
• /
• v.25 no.6
• /
• pp.1-12
• /
• 2008

Objectives : Joongjeo($TE_3$) Supplementation Aekmoon($TE_2$) Draining is a method belongs to Ohaeng-acupuncture, using directional supplementation and draining. Methods : This study was designed to investigate the effects of $TE_3$ supplementation $TE_2$ draining on changes in cerebral blood flow(rCBF) and mean arterial blood pressure(MABP) in normal rats. For these reasons, the present author investigated rCBF and MABP using laser doppler flowmeter in normal rats. In addtion, the present author also investigated action mechanisms of $TE_3$ supplementation $TE_3$ draining on changes in rCBF and MABP too. Results : In this results, $TE_3$ supplementation $TE_2$ draining elevated rCBF in time-dependent manner, but MABP levels decresed by $TE_3$ supplementation $TE_2$ draining. Pre-treatment with indomethacin (IDM), an inhibitor of cyclooxygenase, inhibited increase of rCBF effectively. But pre-treatment with methylene blue(MTB), an inhibitor of guanylate cyclase, decreased rCBF levels. In addition, pre-treatment with IDM also decreased MABP levels, but pre-treatement with MTB increased MABP levels. Conclusions : In conclusion, these results suggest that $TE_3$ supplementation $TE_2$ draining is effective to treat patient with disease related to cerebral ischemia, because $TE_3$ supplementation $TE_2$ draining can increase rCBF. In addition, the mechanisms are thought to be related to guanylate cyclase pathways.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.11 no.12
• /
• pp.2287-2297
• /
• 2007

The proposed ANIDS(Advanced Network Intrusion Detection System) which is network-based IDS using Association Rule Mining, collects the packets on the network, analyze the associations of the packets, generates the pattern graph by using the highly associated packets using Association Rule Mining, and detects the intrusion by using the generated pattern graph. ANIDS consists of PMM(Packet Management Module) collecting and managing packets, PGGM(Pattern Graph Generate Module) generating pattern graphs, and IDM(Intrusion Detection Module) detecting intrusions. Specially, PGGM finds the candidate packets of Association Rule large than $Sup_{min}$ using Apriori algorithm, measures the Confidence of Association Rule, and generates pattern graph of association rules large than $Conf_{min}$. ANIDS reduces the false positive by using pattern graph even before finalizing the new pattern graph, the pattern graph which is being generated is compared with the existing one stored in DB. If they are the same, we can estimate it is an intrusion. Therefore, this paper can reduce the speed of intrusion detection and the false positive and increase the detection ratio of intrusion.

• International conference on construction engineering and project management
• /
• 2020.12a
• /
• pp.157-166
• /
• 2020

Automated rebar fabrication, which requires effective information exchange between model designers and fabricators, has brought the integration and interoperability of data from different sources to the notice of both academics and industry practitioners. Industry Foundation Classes (IFC) was one of the most commonly used data formats to represent the semantic information of prefabricated components in buildings, whereas the data format utilized by rebar fabrication machine is BundesVereinigung der Bausoftware (BVBS), which is a numerical data structure exchanging reinforcement information through ASCII encoded files. Seamless transformation between IFC and BVBS empowers the automated rebar fabrication and improve the construction productivity. In order to improve data interoperability between IFC and BVBS, this study presents an IFC extension based on the attributes required by automated rebar fabrication machines with the help of Information Delivery Manual (IDM) and Model View Definition (MVD). IDM is applied to describe and display the information needed for the design, construction and operation of projects, whereas MVD is a subset of IFC schema used to describe the automated rebar fabrication workflow. Firstly, with a rich pool of vocabularies practitioners, OmniClass is used in information exchange between IFC and BVBS, providing a hierarchy classification structure for reinforcing elements. Then, using International Framework for Dictionaries (IFD), the usage of each attribute is defined in a more consistent manner to assist the data mapping process. Besides, in order to address missing information within automated fabrication process, a schematic data mapping diagram has been made to deliver IFC information from BIM models to BVBS format for better data interoperability among different software agents. A case study based on the data mapping will be presented to demonstrate the proposed IFC extension and how it could assist/facilitate the information management.