• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1101-1103
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• 2010

과거 인터넷을 사용하지 않는 시스템의 경우 소프트웨어의 안전성과 강건성은 철도, 국방, 우주, 항공, 원자력 등 오류 없이 수행되어야 하는 임베디드 소프트웨어에 국한되어 있었다. 그러나 인터넷의 발전으로 인터넷을 통한 정보의 교류 및 서비스가 증대하면서 소프트웨어의 보안품질은 개인, 사회, 국가 모두에게 정보보호의 중요성을 더욱 강조하고 있다. 특히 오류 없이 수행되어야 하는 고안전성 소프트웨어의 개발 기법은 이제 응용 소프트웨어의 보안강화 활동에 활용 되고 있다. 시큐어 코딩 (Secure Coding)은 방어적 프로그램(Defensive Programming)을 포함하는 개념으로 소프트웨어의 안전성과 보안성을 향상 시킬 수 있다. 본 논문에서는 C 언어의 취약가능성 유발 명령어를 예를 들고 시큐어 코딩 기법을 적용하여 취약한 코드를 개선하였다. 이러한 개선을 통해 보안 취약성 유발 가능한 코드 부분을 손쉽게 수정하여 소프트웨어 보안품질을 개선할 수 있다.

• The Journal of the Acoustical Society of Korea
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• v.32 no.5
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• pp.377-384
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• 2013

In this paper, performance of COFDM (Coded Orthogonal Frequency Division Multiplexing) which is OFDM with a forward error correction code, is studied in frequency selective fading underwater acoustic communication channel. The OFDM is a multiplexing technique resistant to frequency selective multipath channel. In OFDM, a broadband information signal is transformed into several narrow band signals and transmits narrow band signals whose bandwidths are less than the channel coherence bandwidth. However, its performance is degraded in a specific narrow band signal due to its deep fading by multipath. To mitigate this degradation, COFDM which is OFDM with convolution code as a forward error correction code, is evaluated. The performance of COFDM is found to be better than that of OFDM in multipath channel.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.1
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• pp.45-49
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• 2011

Cooperative multihop communications support effective transmissions over underwater acoustic channels as inferior wireless channels. But the performance of cooperative multihop systems may degrade due to the lack of cooperative nodes at the initial operation time duration. At the initial time duration, the lack of cooperative nodes causes more errors, and the multihop network propagates these errors. In this paper, we apply fountain code to the cooperative multihop system at the initial time duration, and show performance improvements by simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.4
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• pp.659-665
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• 2015

Recent studies on network coding scheme for increasing transmission efficiency of the network has been actively conducted. In this paper, we apply RLNC in sub-packet unit and propose a joint scheme of sub-packet level network coding and LDPC code. The proposed method can have similar ability of network coding and obtain further error correction capability. The simulation results show that the proposed one enhances error correction capability compared to the case using only LDPC when extra packets are received.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.391-394
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• 2022

최근 한국을 포함한 여러 국가들에서 프로그래밍 교육이 중요시 되고 있다. 그러나 이런 상황으로 인해 더 많아진 학생들은 미숙함으로 인해 숙련자에 비해 더 많은 오류를 만나지만 이를 해결하기 위한 디버깅 실력은 아직 미숙하다. 따라서 본 논문에서는 프로그래밍 교육 지원을 위한 초보자용 GUI 디버깅 도우미 UDB (Unity-DeBugger)를 제안한다. UDB는 제출한 학생 코드를 분석하여 반응형 추적표와 오류 로그를 생성하고 이를 기반으로 GUI 및 애니메이션으로 만들어 학생과 상호작용한다. 특히 UDB는 반응형 추적표를 통해 프로그램 안에 있는 변수들의 현재 상태를 보여주고 순방향 추적뿐만 아니라 기존 IDE의 디버깅 도구들과는 다르게 역방향 추적이 가능하다는 큰 특징이 있다. 이런 UDB를 예시 코드에 실제로 적용한 결과를 통해 미숙한 학생도 역방향 추적 기능을 사용하여 오류 원인을 쉽게 찾을 수 있음을 보인다.

• The Journal of the Acoustical Society of Korea
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• v.32 no.1
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• pp.86-94
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• 2013

In this paper, we propose a network coding scheme that is one of the most promising techniques for overcoming transmission errors in underwater acoustic communications. It is assumed that the proposed scheme operates in a Code Division Multiple Access (CDMA) network where multiple sensor nodes share the underwater acoustic channel in both the frequency and the time domains by means of orthogonal codes. The network topology deploys multi-hop transmission with relaying between multiple source nodes and one destination node via multiple relay nodes. The proposed scheme is evaluated in terms of the successful packet delivery ratio of end-to-end transactions under varying packet loss rates. A computer simulation shows that the successful delivery ratio is maintained at over 95% even when the packet loss rate reaches 50%.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.3C
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• pp.315-326
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• 2003

Abstract In this paper, an improved index assignment procedure is proposed to reduce the channel error effect in a communication system employing classified vector quantization(CVQ). The proposed algorithm consists of two parts: inner index assignment (IIA) and cross index assignment (CIA). The II A reduces the distortion resulting from the error in order bits, presenting the identity of each code vector in a subcodebook. The CIA modifies the indexes assigned by the IIA in such a way that the effect of the channel error occurring in class bits, indicating the class information of the code vector, can be minimized. Simulation results show that the proposed algorithms enable a reliable communication over noisy channels even without employing the channel encoding. Index Terms Classified vector quantization, index assignment.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.3
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• pp.495-508
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• 2023

This paper proposes a method to find out the type and location information of Pauli X, Y, Z errors generated in quantum channels using only the quantum information processing part of the multiple-rate quantum turbo short-block code without external help from the classical information processing part. In order to obtain the location information of the Pauli X,Y error, n-auxiliary qubits and n-CNOT gates were inserted into the C[n,k,2] QSBC-QURC encoder. As a result, the maximum coding rate is limited to about 1/2 as the trade-off characteristics. The location information of the Pauli Z error for C[n,k,2] QSBC-QURC was obtained through the Clifford-based stabilizer measurement. The proposed method inherits all other characteristics of C[n,k,2] QSBC-QURC except for the coding rate.

• The KIPS Transactions:PartC
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• v.13C no.7 s.110
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• pp.803-812
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• 2006

This paper analytically evaluates the FEC(Forward Error Correction) symbol size's effect on the performance and energy consumption of 802.11 protocol with the block FEC algorithm over WSN(Wireless Sensor Network). Since the basic recovery unit of block FEC algorithms is symbols not bits, the FEC symbol size affects the packet correction rate even with the same amount of FEC check bits over a given WSN channel. Precisely, when the same amount of FEC check bits are allocated, the small-size symbols are effective over channels with frequent short bursts of propagation errors while the large ones are good at remedying the long rare bursts. To estimate the effect of the FEC symbol site, the paper at first models the WSN channel with Gilbert model based on real packet traces collected over TIP50CM sensor nodes and measures the energy consumed for encoding and decoding the RS (Reed-Solomon) code with various symbol sizes. Based on the WSN channel model and each RS code's energy expenditure, it analytically calculates the transmission efficiency and power consumption of 802.11 equipped with RS code. The computational analysis combined with real experimental data shows that the RS symbol size makes a difference of up to 4.2% in the transmission efficiency and 35% in energy consumption even with the same amount of FEC check bits.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.05a
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• pp.432-435
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• 2022

최근 IT 산업의 지속적인 발전으로 사용자들을 위협하는 악성코드, 피싱, 랜섬웨어와 같은 사이버 공격 또한 계속해서 발전하고 더 지능화되고 있으며 변종 악성코드도 기하급수적으로 늘어나고 있다. 지금까지의 시그니처 패턴 기반의 탐지법으로는 이러한 방대한 양의 알려지지 않은 악성코드를 탐지할 수 없다. 따라서 CNN(Convolutional Neural Network)을 활용하여 악성코드를 탐지하는 기법들이 제안되고 있다. 이에 본 논문에서는 CNN 모델 중 낮은 인식 오류율을 지닌 모델을 선정하여 정확도(Accuracy)와 F1-score 평가 지표를 통해 비교하고자 한다. 두 가지의 악성코드 이미지화 방법을 사용하였으며, 2015 년 이후 ILSVRC 에서 우승을 차지한 모델들과, 추가로 2019 년에 발표된 EfficientNet 을 사용하여 악성코드 이미지를 분류하였다. 그 결과 2 바이트를 한 쌍의 좌표로 변환하여 생성한 256 * 256 크기의 악성코드 이미지를 ResNet-152 모델을 이용해 분류하는 것이 우수한 성능을 보임을 실험적으로 확인하였다.