• Journal of Aerospace System Engineering
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• v.14 no.1
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• pp.54-61
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• 2020

For operating military aircraft, military certificate of airworthiness (MCA) must be obtained from military authority. Among procedures of general airworthiness certification, there is a military type certification process that aircraft design complies with military airworthiness certification criteria. The Surion is the first military rotorcraft which has obtained military type certificate, production validation and airworthiness certificate in Korea, and the Surion derivatives for special mission are being operated for government services. Based on Aviation Safety Act, in order to operate the Surion derivatives (military aircraft) for special purpose (such as emergency patient transportation and firefighting), the issuance of special airworthiness certificates was needed from civil airworthiness authority, and the restricted category type certification (RTC) is one of design approvals for special airworthiness certification to be streamlined. This study discussed the procedures for acquiring RTC for special purpose operation of the Surion derivatives classified as military derived aircraft, and suggested procedural ideas to improve Korean RTC system.

• Journal of Aerospace System Engineering
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• v.15 no.3
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• pp.93-98
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• 2021

In Europe, it is necessary to fulfil the type certification criteria by the European Aviation Safety Agency (EASA) when developing an aircraft engine. According to type certification criteria, a 150 hours endurance test should be performed to verify the stability of the engine structure under the engine's operating limit conditions. The type certification criteria for the 150 hour endurance test are specified in JAR-E, which is the EASA type certification. Currently, the Arriel 2L2 engine is being developed in cooperation with a foreign manufacturer, and a 150 hours endurance test was performed. In this study, a 150 hours endurance test procedure is conducted in consideration of the operation characteristics of the currently developed engine.

• The Journal of Aerospace Industry
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• s.56
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• pp.45-60
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• 2001

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.06a
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• pp.209-218
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• 2002

보안의 형식검증은 시스템의 초기 상태를 정의하고 트랜잭션을 통해 그 상태를 추적하며 보안을 위해 각 상태를 체크하는 과정이다. 보안 증명이 잘못될 수 있는 경우는 시스템의 초기상태를 정의할 때와 상태가 안전하기 위한 조건을 정의할 때인데, 본 논문에서는 상태 트랜잭션을 위해 BAN 논리를 이용하여 대표적인 지불프로토콜인 NetBill 프로토콜에 대한 형식기법을 제안하였으며, 보안 프로토콜의 증명을 위해 BAN 논리의 확장을 제시했다. 이러한 확장된 연구결과는 원자성, 익명성 및 프라이버시와 같은 다른 중요한 보안의 특성을 증명하기 위해 이용될 수 있다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.201-204
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• 2017

An comparative analysis between two engine type certification specifications which are FAR Part 33 and EASA CS-E has been performed to provide fundamental information for validity assessment of civil certified engine when it is installed to a military rotorcraft. The analysis result has been used to build a traceability information between CS-E and MIL-HDBK-516C by which the substantiation data for engine type certification can be used as parts of aircraft propulsion system airworthiness substantiation.

• Journal of Advanced Navigation Technology
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• v.25 no.3
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• pp.185-193
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• 2021

The system needs to be modified to improve the performance of the aircraft in operation or to satisfy the requirements of related laws. Appropriate standards are required for the technical skills for remodeling the aircraft system, design verification for airworthiness of the aircraft, and supplemental type certification (STC) certification procedures for type certification. This study analyzes the current status and demand of domestic aircraft remodeling, examines the current supplementary type certification procedure, and diagnoses the problem. In addition, as a result of researching measures to improve remodeling technology and certification capabilities to extend the life of the aircraft, improvements in the education system were derived to improve the domestic additional type certification process, such as approval of remodeling agencies and appointment of qualifications for each professional technician.

• Journal of Educational Research in Mathematics
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• v.23 no.2
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• pp.173-192
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• 2013

It may be replacement proofs with understanding and explaining geometrical properties that was a remarkable change in school geometry of 2009 revised national curriculum for mathematics. That comes from the difficulties which students have experienced in learning proofs. This study focuses on one of those difficulties which are caused by the forms of proofs: using letters for designating some sides or angles in writing proofs and understanding some long sentences of proofs. To overcome it, this study aims to investigate the applicability of Byrne's method which uses coloured diagrams instead of letters. For this purpose, the proofs of three geometrical properties were taught to middle school students by Byrne's visual method using the original source, dynamic representations, and the teacher's manual drawing, respectively. Consequently, the applicability of Byrne's method was discussed based on its strengths and its weaknesses by analysing the results of students' worksheets and interviews and their teacher's interview. This analysis shows that Byrne's method may be helpful for students' understanding of given geometrical proofs rather than writing proofs.

• School Mathematics
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• v.15 no.3
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• pp.651-665
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• 2013

The aim of this study is to find how unformal proof activities contribute to solving problems successfully and to confirm the role of teachers in the progress. For this, we developed a task that can help students communicate actively with the concept of unformal proof activities and conducted a case lesson with 6 graders in Elementary school. The study shows that unformal proof activities contribute to constructing representations which are needed to solve math problems, setting up plans for problem-solving and finding right answers accordingly as well as verifying the appropriation of the answers. However, to get more out of it, teachers need to develop a variety of tasks that can stimulate students and also help them talk as actively as they can manage to find right answers. Furthermore, encouraging their guessing and deepening their thought with appropriate remarks and utterances are also very important part of what teachers need to have in order to get more positive effect from these activities.

• Journal of Aerospace System Engineering
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• v.15 no.3
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• pp.20-29
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• 2021

As the feasibility of urban air mobility (UAM) service using electric vertical take-off and landing (eVTOL) aircraft increases due to aircraft electrification, distributed propulsion, and artificial intelligence technologies, the U.S. and European aeronautical societies have been improving their certification system and regulations for the type certification of eVTOL. The improved certification system is expected to be ready in the near future, after the European Union Aviation Safety Agency (EASA) proposed the VTOL Special Condition, SC-VTOL in 2019. However, the current domestic certification system is still insufficient to properly respond to eVTOL. This study investigated the development trends of foreign eVTOL and certification systems, identified considerations to improve the domestic certification system, and proposed the measures for type certificates and type certificates validation of eVTOL based on the comparison between SC-VTOL and Korea airworthiness standards (KAS).

• School Mathematics
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• v.13 no.3
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• pp.501-524
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• 2011

The purpose of this study was to develop teaching-learning materials for informal activities geared toward teaching the nature and structure of proof, to make a case analysis of the application of the developed instructional materials to students in an elementary gifted class, to discuss the feasibility of proof education for gifted elementary students and to give some suggestions on that proof education. It's ultimately meant to help improve the proof abilities of elementary gifted students. After the characteristics of the eight selected gifted elementary students were analyzed, instructional materials of nine sessions were developed to let them learn about the nature and structure of proof by utilizing informal activities. And then they took a lesson two times by using the instructional materials, and how they responded to that education was checked. An analysis framework was produced to assess how they solved the given proof problems, and another analysis framework was made to evaluate their understanding of the structure and nature of proof. In order to see whether they showed any improvement in proof abilities, their proof abilities and proof attitude were tested after they took lessons. And then they were asked to write how they felt, and there appeared seven kinds of significant responses when their writings were analyzed. Their responses proved the possibility of proof education for gifted elementary students, and seven suggestions were given on that education.