• Journal of the Korean Institute of Intelligent Systems
• /
• v.23 no.6
• /
• pp.558-564
• /
• 2013

Wireless sensor networks (WSNs) contain limited energy resources and are left in open environments. Since these sensor nodes are self-operated, attacks such as sinkhole attacks are possible as they can be compromised by an adversary. The sinkhole attack may cause to change initially constructed routing paths, and capture of significant information at the compromised node. A localized encryption and authentication protocol (LEAP) has been proposed to authenticate packets and node states by using four types of keys against the sinkhole attack. Even though this novel approach can securely transmits the packets to a base station, the packets are forwarded along the constructed paths without checking the next hop node states. In this paper, we propose the next hop node selection method to cater this problem. Our proposed method evaluates the next hop node considering three factors (i.e., remaining energy level, number of shared keys, and number of filtered false packets). When the suitability criterion for next hop node selection is satisfied against a fix threshold value, the packet is forwarded to the next hop node. We aim to enhance energy efficiency and a detour of attacked areas to be effectively selected Experimental results demonstrate validity of the proposed method with up to 6% energy saving against the sinkhole attack as compared to the LEAP.

• KIISE Transactions on Computing Practices
• /
• v.23 no.9
• /
• pp.535-541
• /
• 2017

Today, the scale of the computer software market has increased, and massive sized software has been developed to satisfy diverse requirements. In this context, software complexity is increasing and the quality of software is becoming more difficult to manage. In particular, software reuse is important for the improvement of the environments of legacy systems and new system development. In this paper, we propose a method to reuse modules that are certified by quality. Reusable levels are divided into code area (method, class, and component), project domain, and business levels. Based on the coupling and cohesion of software complexity, we propose a reusable module extraction mechanism with reusability metrics, which constructs a visualization of the "reusable module's chunk" based on the method and class levels. By applying reverse engineering to legacy projects, it is possible to identify reusable modules/objects/chunks. If these modules/objects/chunks are to be reused to develop an extension system or similar new system, we need to ensure software reliability in order to reduce the time and cost of software development.

• Journal of Aerospace System Engineering
• /
• v.12 no.4
• /
• pp.1-8
• /
• 2018

The state of registry issues a type certificate validation (TCV) based on the satisfactory evidence that the product (aircraft, engine, and propeller) is in compliance with the appropriate airworthiness requirements. The Korean government performs an evaluation to determine whether the product complies with Korean airworthiness standards for issuing TCV according to the Korean aviation safety law. Recently, the Validation Principles Working Group (VPWG) has developed a risk-based model for validation of civil aeronautical products. Also, VPWG proposed to incorporate this validation model into the corresponding ICAO Standards and Recommended Practices and guidance material. In this paper, we have reviewed the validation model and discussed improvements in the validation process.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.31 no.10
• /
• pp.97-104
• /
• 2003

This paper addresses EMC test results for the EQM Communications & Broadcasting Satellite(CBS) Ka-band Payload System. The aim of the EMC test is to verify that the payload system has no effect on the other system and is not affected by the external field. The compliance of EMC system requirements was verified by the analysis and measurement of the emission level from the payload system. The variation of performance by noise injection was measured to inspect the susceptibility of the payload system. The analysis and test results also showed that the electromagnetic interference has no serious effect on the overall payload system performance. It is confirmed that the EQM CBS Ka-band payload system can be operable in the space environment from the EMC performance's viewpoint. It is also obtained that better performance can be acquired by improving waveguide design and integration method.

• The Transactions of the Korea Information Processing Society
• /
• v.4 no.2
• /
• pp.543-551
• /
• 1997

Many areas of human activities are computerized with the wide spread use of computers and communication networks.Electrinic voting is an important social activity in democtatic society.The realization of electronic democracy is based on the sectrity of edectronic voting scheme.Therefore, it is necessary to use the cryto-graphic technique for secure electronic voting scheme.Therefore, it is necessary to use the cryto-graghic technique for secure election.In this stusy, an dedctronic voting scheme sutiable for large election is proposed.In order to make practi-cal volting scheme, we assume that the voting authorization center is trustful and the chaum's anonymous com-munication channel[6] prepared before the election day.The center authorizes the ballot of eligible voter by using the ID based digital signature scheme in the registeation stage.During the voting stage, undeniable chal-lenge/ response prorocol is performed between the center and the boters to ensure that the intemediate voting results should not affect the entire.The proprsed scheme fully conforms to the requirments of large scale election such as privacy of the voters, fairness, unresuability, unforgeability and eligbility.

• Journal of Advanced Navigation Technology
• /
• v.27 no.6
• /
• pp.821-827
• /
• 2023

In this study, the aircraft technical standards of the Korea and the United States were analyzed to derive the dynamometer test procedure required to prove the compatibility for flight test certification of the metal brake pad for transport aircraft. Since the design modification of the brake systems is classified as a major change, the STC(Supplemental Type Certificate) and the PMA(Parts Manufacturer Approval) are required. In accordance with the TSO-C135a, the technical standard order for brake system in the United States, the design landing-stop test, accelerate-stop test, and most severe landing stop test were selected among the test items for flight test. The conditions for the dynamometer test are determined according to the specifications provided by aircraft manufacturer, and the brake pad condition, deceleration, and the number of test are defined according to the TSO-C135a.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2010.05a
• /
• pp.7-7
• /
• 2010

형상기억합금은 합금이 갖는 형상기억효과 및 초탄성효과 때문에 학문적으로 공업적으로 큰 흥미를 끌어왔다. 형상 기억효과는 Au-Cd 합금과 Cu-Zn 합금에서 최초로 발견되었지만 당시에는 크게 주목을 받지 못하였다. 그 후 1962년 Ti-Ni 합금에서 형상기억효과가 발견된 이래로 크게 주목을 받게 되었고, 곧바로 상용화를 위한 노력이 이어져 리벳, 열엔진, 커플링, 회로차단기 등에 적용이 시도되었다. 현재까지 약 300여종에 이르는 형상기억합금이 개발되어 있지만 형상기억효과의 안정성, 우수성, 내식성, 가공성, 내피로성, 내마모성이 우수한 Ti-Ni 합금이 가장 실용화에 적합한 합금으로 인식되고 있다. Ti-Ni합금은 1960년대에 개발되었지만 의료분야에 적용되기 시작한 것은 1980년대이고, 그 후 미국의 FDA가 Ti-Ni 합금으로 제조된 몇몇 3급(Class III) 임플란트를 인증하면서 시장규모도 폭발적으로 증가하고 있다. 일본의 경우 1980년대 초부터 Ti-Ni 합금을 치과용 임플란트로써 사용하여 왔, 독일, 중국, 러시아도 1980년대부터 임상에 적용해 왔다. 우리나라는 2004년 식약청(식품의약안정청)으로부터 제조 및 판매가 허가되어 현재 실제 임상에 적용되고 있다. 이와 같이 Ti-Ni 합금이 의료용 금속재료로서 널리 쓰이게 된 가장 근본적인 이유는 말할 나위 없이 합금이 갖는 형상기억효과 및 초탄성효과 때문이다. 본 강연에서는 Ti-Ni 합금을 의료용 금속재료의 입장에서 재조명해보고, 본 합금이 의료용 금속재료로서 어떠한 장점이 있으며, 그러한 장점을 의료분야에서 어떻게 응용하고 있는가에 대해 소개하고자 한다. 또한 의료용 Ti-Ni 합금에서 향후 개선되어야 할 요소에 대해서도 논의하고자 한다.

• Proceedings of the KSR Conference
• /
• 2008.06a
• /
• pp.603-609
• /
• 2008

Nowadays, double-system of TFM(Track-side Functional Modules) developed instead of single-system in use of high speed line to acquisition more availability. Safety Law for Railroad recommend to quality certification of development and general railway machines. It is important to select metrics which form the bases for testing software products. A number of package software development part do not open source cords, so testing external characteristic vectors having relationship with metrics. In this paper, review the process for the TFM Point Modules, Universal Modules and Switchers, think about the test methode of circuit boards output performance by using TFM tester and Simulators.

• Journal of Digital Convergence
• /
• v.11 no.3
• /
• pp.279-284
• /
• 2013

Wireless access network section needs strong security which supports high data rate and mobility not to invade patient's privacy by exposing patient's sensitive biometric from automatic implantable device that is adapted to u-healthcare service. This paper builds test bed and performs assessment and measurement of security ability of WiMAX network to transmit and receive mobile patient's biometric by building WiMAX network in wireless access network not to expose paitne's biometirc at wireless access network section to the third person. Specially, this paper compares and assesses data security, MAC control message security, handover conection delay, and frame loss and bandwidth of ECDH at the layer of WiMAX security compliance, WiMAX MAC IPSec, and MAC.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2000.04a
• /
• pp.615-619
• /
• 2000

최근 급증하고 있는 인터넷 전자상거래의 가장 필수적인 부분이 전자지불 시스템이다. 전자적으로 처리되는 지불시스템은 사용자의 익명성 보장, 지불정보의 위조 및 재사용방지 등의 특징을 가지며, 거래 주체들간의 신뢰구축을 위한 상호 인증이 요구된다. 디지털 기술의 발달로 소액의 디지털 상품들이 많이 등장함에 따라 소액 상품만을 결제하기 위한 소액지불 시스템의 필요성이 증대되면서, Millicent, PayWord, MicroMint, MPTP 등의 소액 지불 시스템들이 연구되었으나 아직 효과적으로 사용되지 못하고 있다. 이러한 소액 지불 시스템의 경우에는 소비자가 한 상점에서 연속적인 거래를 수행하는데 따르는 비용을 먼저 생각해야 한다. 그 이유는 소액거래를 하는 대부분의 소비자들은 여러 개의 상품을 연속적으로 구입하는 경향을 가지기 때문이다. 또한 거래 주체간의 대금결제의 편의성을 도모하기위한 선불방식에 대한 연구가 필요하다. 그러나, 기존의 소액 지불 시스템들은 연속거래에 있어 제한적이거나 소비자의 신용을 기반으로 한 후불방식을 채택하고 있어 소비자의 화폐남용에 대한 자원낭비의 문제를 안고있다. 이에 본 논문에서는 Hash Chain을 이용하여 연속거래에 적합한 선불방식의 소액전자지불 시스템을 제안한다.