• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.138-140
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• 2012

타임드 오토마타 모델 기반 개발 방법을 지원하는 TIMES 도구는 실시간 소프트웨어에 대한 타임드 오토마타 모델 명세, 시뮬레이션, 검증, BrickOS 기반 코드 생성을 지원한다. 하지만 BrickOS 기반 코드는 엄격한 실시간 제약성 만족을 지원하지 않아서 실시간 내장형 소프트웨어 개발에 그대로 사용하기가 어렵다. 본 논문에서는 타임드 오토마타 모델로부터 실시간 내장형 소프트웨어 구현에 사용될 수 있는 VxWorks 기반 코드를 체계적으로 생성하기 위한 방법을 제안한다. TIMES 도구를 사용해 자동 생성된 BrickOS 기반 코드에서 플랫폼 독립적인 코드는 활용하고, 플랫폼 의존적인 코드들을 분류해 내어 각각 VxWorks 기반 코드로 변환하는 방법을 제안한다. 내장형 소프트웨어 개발시 타임드 오토마타 모델 기반 개발 방법의 적용 가능성을 확인하기 위해 변환 항목들을 통해 생성된 VxWorks 기반 코드에 대한 테스트를 수행하고 결과를 분석한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.9
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• pp.2022-2028
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• 2015

SpaceWire is a standard for high-speed links and networks between spacecraft components, which was invented for better, cheaper and faster on-board data handling in spacecraft. The standard defines timecode and its distribution which can be used for time synchronization among the nodes in a SpaceWire network. A timecode output from the time master which provides standard time over a SpaceWire network travels through links and routers to reach every nodes. While traveling, a timecode suffers from transmission delay and jitter which cause some difference in time synchronization among nodes. In this work, a simulator was developed using OMNeT++ to simulate the operation of a SpaceWire network and some analyses were performed on the transmission delay and jitter accompanied with a transmission of a timecode. The result will be used in the near future for the research of a precise time synchronization technique over a SpaceWire network.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.715-718
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• 2016

SpaceWire invented for on-board data handling in a spacecraft has Time-Code defined for time synchronization over SpaceWire network. Delay and jitter of the transmission of Time-Code caused when a Time-Code travels through a network are the main reasons of time synchronization error. This work proposes a scheme that can reduce the time synchronization error by using extended Time-Codes. The proposed scheme can remove both transmission jitter and transmission delay. The scheme will be validated in a simulation environment built with OMNeT++.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.4
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• pp.724-730
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• 2017

SpaceWire invented for spacecrafts has Time-Code defined for time synchronization over SpaceWire network. A Time-Code suffers transmission delay of 14[bit-period] and jitter up to 10[bit-period] whenever it passes through a SpaceWire link, which is the primary cause of time synchronization error. This work presents a simple method to improve the time synchronization which uses two extended Time-Codes. Nodes on a SpaceWire network can find how much delay and jitter a received Time-Code has suffered while it passes through the network, and they can correct time synchronization error with this information. The proposed method was validated in a simulation environment developed based on OMNeT++. The simulation result showed that time synchronization error less than a few bit-periods can be achieved. The proposed method is cost effective and suitable for small-scale SpaceWire network systems.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.3
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• pp.443-454
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• 2020

The JavaScript engine is a module that receives JavaScript code as input and processes it, among many functions that are loaded into web browsers and display web pages. Many fuzzing test studies have been conducted as vulnerabilities in JavaScript engines could threaten the system security of end-users running JavaScript through browsers. Some of them have increased fuzzing efficiency by guiding test coverage in JavaScript engines, but no coverage guided fuzzing of optimized, dynamically generated machine code was attempted. Optimized JavaScript codes are difficult to perform sufficient iterative testing through fuzzing due to the function of runtime guards to free the code in the event of exceptional control flow. To solve these problems, this paper proposes a method of performing fuzzing tests on optimized machine code by avoiding deoptimization. In addition, we propose a method to measure the coverage of runtime-guards by the dynamic binary instrumentation and to guide increment of runtime-guard coverage. In our experiment, our method has outperformed the existing method at two measures: runtime coverage and iteration by time.

• Journal of KIISE
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• v.44 no.12
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• pp.1307-1312
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• 2017

Due to their convergence with state-of-the-art ICT technologies, the complexity and reliability demands of industrial automation systems have been rapidly increasing. In recent years, to cope with these demands, several research works have been carried out to adopt formal methods to the application development cycle at the early design stage. In this paper, we propose an automated code generation framework for industrial automation applications, based on a timed automata model. As a case study, we developed a formal model for a traffic light control system and verified the timing properties described in the specification. We finally demonstrated that the operation of a test-bed based on the auto-generated native code was identical to that of the model specification.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.32 no.4
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• pp.72-84
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• 2014

• Proceedings of the Korean Information Science Society Conference
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• 2003.04c
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• pp.91-93
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• 2003

급격히 발전해 온 엔터프라이즈 환경에 대하여 체계적으로 소프트웨어 개발 패러다임이 변하고 있다. 이종 플랫폼, 나아가 이종 개발 플랫폼을 자유로이 연동시킬 수 있는 개발 방법에 대한 필요성이 대두되면서 MDA 개념이 등장하였다. MDA는 프로그래밍 언어 흑은 런타임 플랫폼에 독립적인 모델에 의해 개발하는 방식으로, 개발된 모델을 특정 플랫폼에 알맞은 형태로 변환함으로써 개발 모델 및 코드의 재사용성을 극대화한다. 본 논문에서는 MDA 개발에 있어서 특정 플랫폼에 알맞은 코드를 생성하기 위한 기능과 그 설계 방안을 논한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.4B
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• pp.278-287
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• 2012

In this paper, we propose an allocation scheme for variable message packings to increase efficiency of military operation using Link-16 which is well-known for tactical data link by delivering imagery information rapidly. We propose a variable message packing scheme using COC waveform to support variable data rate under some coverage limitation. Variety of message packing makes Link-16 vary transmission rate appropriately for tactical environment. We also propose a allocation scheme to assign message packing to time slot properly. Finally we verify the performance and superiority of proposed ideas by simulations.

• Review of KIISC
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• v.32 no.3
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• pp.27-31
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• 2022

랜섬웨어 침해사고의 감염대상의 규모를 가리지 않는 특성과 폭발적인 증가세로 인해 전 세계적인 대응방안 마련의 공감대가 형성된 지 오래이다. 침해사고 분석 관점에서 랜섬웨어 사고는 기존 침해사고와 달리 랜섬웨어 악성코드가 사용되었다는 가장 큰 특징 이 외에 별다른 차이가 없다. 여타 침해사고와 동일하게 공격 도구를 생산하고 인프라를 구축하는 단계부터, 타겟 시스템으로의 최초 침투, 권한 상승, 내부 전파를 거쳐 최종적으로 랜섬웨어 악성코드가 실행되는 흐름을 보인다. 한편, 랜섬웨어 공격조직은 보다 원활한 공격을 위하여 점차 분업화, 조직화되는 동향을 보이기 때문에 공급 사슬을 차단하려는 노력도 수반되어야 한다. 본고에서는 랜섬웨어 위협을 공격 타임라인으로 나누어, 산학연관에서 어떠한 방향으로 대응 노력을 기울이고 있는지 소개한다.