• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.48 no.12
• /
• pp.969-976
• /
• 2020

Urban Air Mobility is attracting attention as a future innovation industry around the world, and leading industries are considering the application of composite materials for structural robustness and lightening in the designing and manufacturing new concept eVTOL aircraft. To apply composite materials to the new concept of eVTO aircraft, this paper was analyzed about composite material qualification system of FAA & EASA and institutionalized by Korea Government, including the procedures and methods, the organization to carry out the material verification for domestic conditions. The domestic composite material qualification system will not only make it easier for manufacturers of eVTOL aircraft with a new concept to apply composite materials to domestic aircraft through pre-material qualification, but also reduce the burden of material qualification within the period of type certification. In addition, domestic manufacturers of composite materials with qualified material quality and performance will be easy to enter for domestic aircraft applications and composite material manufacturers with experience in applying to aircraft will have a positive impact on overseas exports. This system will be able to promote the development eVTOL aircraft industry of a new concept and enhance international credibility of made aircraft in Korea.

• The Transactions of the Korea Information Processing Society
• /
• v.5 no.11
• /
• pp.2921-2929
• /
• 1998

We propose an efficient off-line electronic cash system based on the certificate issued by Certificate Authority. It satisfies all the basic requirements for electronic payment system such as cash unforgeability, cash anonymity, double spending detection, no framing, etc. Our proposed system is very computationally efficient in the sense that: (1) the number of exponentiation operation imposed on the user during withdrawal phase is much smaller than any existing off-line electronic cash schemes, (2) all the computation of user's during withdrawal phase can be performed by off-line pre-processing. So the proposed system is suitable to be implemented by smart cards in both memory and computation.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.11A
• /
• pp.1047-1055
• /
• 2005

One of major characteristics in wireless LAN is terminal's frequent mobility, so it makes many overheads in the process of authentications repeatedly at each handoffs. So I propose IAPP(Inter Access Point Protocol) of IEEE 802.11f, modified context block and 4 way handshake of IEEE 802.11i, in order to implement secure and rapid handoff. The context block. I proposed, doesn't makes any communication with RADIUS server at handoff period. Therefore, it guarantee higher efficiency than existing handoff mechanisms. Also it can improve security vulnerability by padding authentication field in the context block for providing in advance against Replay and DoS(Denial of Service) attacks.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
• /
• 2003.12a
• /
• pp.393-398
• /
• 2003

본 논문에서는 사용자 인증에 사용되는 패스워드 검증자의 안전성을 더욱 보강한 새로운 패스워드 검증자 기반 키 분배 프로토콜을 제안한다 기존 패스워드 기반 키 분배프로토콜 방식은 네트워크 상에서 패스워드의 안전한 전송이 어려웠고, 패스워드 파일의 안전한 보호가 어렵다는 문제가 있었다. 이에 패스워드 파일을 그대로 서버에 저장하지 않고 패스워드를 사용하여 생성한 검증자(verifier)를 저장하게 함으로써 패스워드파일을 보다 안전하게 보호할 수 있게 되었으며, 서버가 사용자의 패스워드를 알지 못하더라도 검증자를 사용한 증명방식을 통해 사용자를 인증할 수 있게 되었다. 본 논문에서는 사용자와 서버의 비밀정보로 만든 새로운 형태의 검증자를 사용하고, 사용자는 다른 저장정보 없이 기억하고 있는 ID와 패스워드만을 사용하여 키 분배를 수행하는 패스워드 검증자 기반 키 분배 프로토콜을 제안한다. 제안하는 프로토콜의 안전성 분석을 위해 active impersonation과 forward secrecy, man-in-the-middle attack, off-line dictionary attack 등의 공격 모델을 적용하였다.

• Convergence Security Journal
• /
• v.17 no.5
• /
• pp.71-76
• /
• 2017

Today, it is an information society where a large number of users access and view important data in a large number of information assets as needed. In this complexity, techniques related Identify Management are being applied, in order to verify authorized user access to important information assets and manage of history. But, the ability access to sensitive information using account has the disadvantage of being able to open the way for information to the attacker when it is hijacked. Thus, in this paper, we propose a secure Identify Management System that can control the use of accounts based on the attitude of the account holder, but also enhances the security and does not hinder the convenience.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.18 no.5
• /
• pp.125-134
• /
• 2008

A great number of RFID authentication protocols have been proposed for the secure RFID system. These are typically divided into three types according to primitive that they use : Hash-based, Re-encryption based, and XORing-based protocol. The well-known attacks in RFID system are eavesdropping. impersonating, location tracking, and so on. However, existing protocols could not provide security against above attacks, or it was not efficient to search for tags on database. Therefore, in this paper we present a protocol which is secure against above attacks by using hash function and makes Database search tags easily by attaining the state information of previous session through the shared values with all tags and database.

• Korean Journal of Childcare and Education
• /
• v.11 no.1
• /
• pp.501-521
• /
• 2015

This study aims to examine the effects of the main eight items amended in the 2013 child care center accreditation system and to provide suggestions. The participants in the study were 200 child care center teachers and staff; 150 professionals consisting of public officials in charge of child care, members for the accreditation committee, and inspectors at the site; and 144 parents. They participated in an on-line questionnaire survey conducted during the end of February, 2014. The survey questions regarding the eight changed items were the same to all the three participating groups, and three more questions were asked to child care center teachers and staff. The collected data were analyzed with frequencies and percentages to present general recognition level. For a group comparison, analysis of variance was first performed among 3 professional groups, all of which has the same size. When there was not a statistically significant difference among the three groups, the second analysis of variance was done among three groups of professionals including the three groups, teachers and staff, and parents. The results showed that there were differences in recognition among the groups regarding each changed item in the 2013 child care center accreditation system, but overall, the groups evaluated the main amendments positively and the changes were considered appropriate and necessary. However, it was found that in-depth reviews are needed of procedure unification to check the basics to require legal compliance; management of unaccredited centers such as valid period reduction and no accreditation, or limit for re-accreditation application; and the burdens of child care centers about surprise visits and notice of inspection dates in advance.

• Proceedings of the Korean Radioactive Waste Society Conference
• /
• 2005.06a
• /
• pp.205-210
• /
• 2005

The proposed regulation for low and intermediate level radioactive waste disposal facility, scheduled to be revised, recommends that the waste generator should verify the radioactive waste conforms to the disposal requirements before disposing of it. According to the regulation, the radionuclide concentration of the radioactive waste, and its physical and chemical characteristics and safety must be confirmed prior to the disposal of low and intermediate level radioactive wastes, and the waste generator is required to deliver this information to the disposal facility operator. In addition, the disposal facility operator must assess the safety of the disposal site to establish the SWAC (Site Specific Waste Acceptance Criteria) in consideration of the characteristics of the site, whereas the waste generator must comply with the criteria in managing, disposing of and delivering low and intermediate level radioactive wastes. To abide by the afore-mentioned regulation and criteria, the waste generator must verify that the radioactive wastes to be disposed of are suitable for disposal before they are transported to the disposal facility, and to this end a radioactive waste certification program must be developed. This study conducted an in-depth analysis of the radioactive waste certification programs enforced in countries advanced in atomic energy to develop a draft of a certification program applicable to local power plants, and the program is currently applied as pilot to Uljin Power Plants No. 1 & 2 to prove its applicability. This study is going to analyze the results of the pilot application with a view to developing a radioactive waste certification program suitable to local conditions.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.3
• /
• pp.1054-1060
• /
• 2013

Fuel tank of a rotorcraft has a great influence on the survivability of crews. For a long time, US army has tried to develop the proper material for fuel cell of a military rotorcraft. As a result, the design specification of fuel cell, MIL-T-27422A, was issued for the first time on 1961. Through a few revisions, it has been developed to ML-DTL-27422D in 2007. It should be assured that fuel cell satisfies the requirement defined in MIL-DTL-27422D. The qualification test of this specification is classified into Phase I test for material and Phase II for fuel cell itself. This paper studies test conditions and procedures of slosh & vibration, gunfire resistance and crash impact test. They are considered as the most important tests which have a high possibility of failure. The rational consideration of this paper can improve the ability for estimating not only the validity of test procedure and test condition but test result. Based on the rational consideration, it is expected that the ability of the systematic development can be improved.

• 한국항공운항학회:학술대회논문집
• /
• 2016.05a
• /
• pp.245-248
• /
• 2016

현대의 항공테러는 단순한 항공기 납치뿐만 아니라 항공기의 공중 폭파, 항공기에 대한 미사일 공격, 공항과 승객에 대한 공격, 그리고 항공 외부 시설에 대한 공격 등 실로 다양한 형태로 자행되고 있다. 항공 교통에서의 불법 방해행위를 사전에 방지하기 위해서는 출발지의 보안 검색이 무엇보다도 중요하며, 이를 위해서 사전 예방적 선제적 항공보안관리 체계 전환, 출입부터 탑승까지 전 과정을 프로세스화한 점검활동 강화, 국제권고기준 항공보안장비 보유와 첨단화 등 미래 변화에 대한 능동적 대처뿐만 아니라 정확한 보안검색과 고객편의의 융합을 통해 세계 최고 공항으로 지향하며, 행동탐지기법의 도입을 통해 일상적이고 포괄적인 보안검색 운영의 약점을 보완하여 항공보안 강화의 토대를 마련해야 하고, 불법 방해행위의 억지를 위해 2015년부터 새롭게 실시하는 국제민간항공기구 상시 모니터링 제도의 항공보안 평가(USAP-CMA) 방식을 적극 검토하여 국정원 공항공사 항공사 등 관련기관 정보 공유, 지속적인 모니터링 및 국내 국제민간항공기구(ICAO) 인증 항공 보안평가관 등과 철저히 대비한 세부 대응 계획을 수립하고 항공보안 전문가 육성을 강구하여야 한다.