• 대한전자공학회논문지TC
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• 제43권10호
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• pp.1-7
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• 2006

다중 송수신 안테나 시스템에서 비트 오류 확률 성능면에서 최적의 기법으로 알려진 ML(Maximum-Likelihood) 복호기를 구현하기 위해 격자 복호 기법이 제안되었다. 그러한 격자 복호 기법에 기반한 복호기에는 구 복호기, K-best 복호기 등이 있으며, K-best 검출 기법은 격자 복호 기법의 실제 구현에 가장 적합하지만 오차 전달 현상에 의한 성능 저하라는 단점이 있다. 본 논문에서는 이러한 K-best 검출 기법의 단점을 보완해 비트 오류 확률 성능을 개선하고 평균 연산량을 낮춘 적응 K-best 기법을 제안하였다.

• 정보처리학회논문지C
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• 제10C권6호
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• pp.717-726
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• 2003

본 논문에서 우리는 방대한 패킷 데이터로부터 침입탐지를 위한 규칙들을 자동으로 생성하는 방법으로 기존 연관규칙을 연역적 알고리즘을 분석하고, 그 결과를 기반으로 침입탐지 시스템에 적용되기 위한 침입 패턴 규칙들을 빠르게 생성할 수 있도록 연연적 알고리즘을 제안하였다. 본 논문에서 제안한고 있는 연역적 알고리즘은 대량의 데이터를 항목별로 분류하고 제거하는 클러스터링 개념에 적합하도록 설계하였다. 이 알고리즘은 적용될 침입탐지 시스템 패턴 생성 및 분석 모듈 방식에 직접적으로 연계되어 있으며, 이것은 침입탐지 시스템에 관한 패턴관리를 위한 규칙 데이터베이스를 구축함으로서 응용범위의 확장은 물론 기존 침입탐지 시스템의 탐지속도를 높일 수 있다. 제안된 연역적 알고리즘의 패텅 생성 기법은 침입탐지 시스템에서 생성되는 데이터의 지원율에 따라 적절히 변경될 수 있는 알고리즘을 사용하였으며, 이 기법에 의한 규칙 생성율의 향상에 따른 규칙생성 속도개선 가능성에 대해 알고리즘 시뮬레이션을 통하여 분석하였다.

• 한국IT서비스학회지
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• 제15권2호
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• pp.157-167
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• 2016

Task environment for enterprises and public institutions are moving into cyberspace-based environment and structing the LTE wireless network. The applications "App" operated in the LTE wireless network are mostly being developed with Android-based. But Android-based malwares are surging and they are the potential DDoS attacks. DDoS attack is a major information security threat and a means of cyber attacks. DDoS attacks are difficult to detect in advance and to defense effectively. To this end, a DMZ is set up in front of a network infrastructure and a particular server for defensive information security. Because There is the proliferation of mobile devices and apps, and the activation of android diversify DDoS attack methods. a DMZ is a limit to detect and to protect against DDoS attacks. This paper proposes an information security method to detect and Protect DDoS attacks from the terminal phase using a Preemptive military strategy concept. and then DDoS attack detection and protection app is implemented and proved its effectiveness by reducing web service request and memory usage. DDoS attack detection and protecting will ensure the efficiency of the mobile network resources. This method is necessary for a continuous usage of a wireless network environment for the national security and disaster control.

• 한국정보과학회논문지:시스템및이론
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• 제34권10호
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• pp.474-492
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• 2007

단백질 상호작용 네트워크는 생체 내에서 특정 역할을 담당하는 패스웨이나 복합체와 같은 중요한 의미의 많은 기능 모듈들을 포함하고 있다. 본 논문에서는 이 기능 모듈들과 정합될 수 있는 개념 모듈을 정의하고 이를 기반으로 원하는 기능 모듈들을 개념적으로 표현하고 효율적으로 탐색할 수 있는 새로운 방법을 제안한다. 개념 모듈은 트리플들과 이들 사이의 연산자로 이루어진 표현 규칙에 의해 정의 되며 탐색하고자 하는 기능 모듈들의 구조를 개념적으로 표현한다. 이 표현 규칙에서의 트리플은 한 기능 모듈을 구성하는 단백질들 사이의 구체적인 상호작용 관계를, 연산자는 트리플들 사이의 구조적인 연관 관계를 각각 개념적으로 정의한다. 또한, 사용자는 사전에 표현 규칙에 의해 잘 정의된 개념들을 조합하여 새로운 의미의 복합 개념 모듈을 정의할 수도 있다. 복합 개념 모듈은 복잡한 기능 모듈들의 개념적 구조를 보다 정교하게 표현할 수 있기 때문에, 사용자 탐색 질의의 의미적 표현력을 획기적으로 높일 수 있다. 정의된 규칙들은 XML로 관리될 수 있어 다른 종류의 단백질 상호작용 네트워크에서 사용자가 유사한 모듈들을 탐색하기 위해 쉽게 적용 가능하다. 본 논문에서는 또한, 구조적으로 복잡한 규칙들을 직관적으로 표현하고 효율적으로 탐색하기 위한 시각화된 질의 환경도 구현하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권9호
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• pp.3712-3729
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• 2020

Smoke detection is helpful for early fire detection. With its large coverage area and low cost, vision-based smoke detection technology is the main research direction of outdoor smoke detection. We propose a two-stage smoke detection method combined with block Deep Normalization and Convolutional Neural Network (DNCNN) and visual change image. In the first stage, each suspected smoke region is detected from each frame of the images by using block DNCNN. According to the physical characteristics of smoke diffusion, a concept of visual change image is put forward in this paper, which is constructed by the video motion change state of the suspected smoke regions, and can describe the physical diffusion characteristics of smoke in the time and space domains. In the second stage, the Support Vector Machine (SVM) classifier is used to classify the Histogram of Oriented Gradients (HOG) features of visual change images of the suspected smoke regions, in this way to reduce the false alarm caused by the smoke-like objects such as cloud and fog. Simulation experiments are carried out on two public datasets of smoke. Results show that the accuracy and recall rate of smoke detection are high, and the false alarm rate is much lower than that of other comparison methods.

• Smart Structures and Systems
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• 제4권6호
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• pp.779-794
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• 2008

Observer-based fault detection and isolation (FDI) filter design method is a model-based method. By carefully choosing the observer gain, the residual outputs can be projected onto different independent subspaces. Each subspace corresponds to the monitored structural element so that the projected residual will be nonzero when the associated structural element is damaged and zero when there is no damage. The key point of detection filter design is how to find an appropriate observer gain. This problem can be interpreted in a geometric framework and is found to be equivalent to the problem of finding a decentralized static output feedback gain. But, it is still a challenging task to find the decentralized controller by either analytical or numerical methods because its solution set is, generally, non-convex. In this paper, the concept of detection filter and iterative LMI technique for decentralized controller design are combined to develop an algorithm to compute the observer gain. It can be used to monitor structural element state: healthy or damaged. The simulation results show that the developed method can successfully identify structural damages.

• Structural Engineering and Mechanics
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• 제67권4호
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• pp.327-336
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• 2018

In this study, an efficient damage index is proposed to identify multiple damage cases in structural systems using the concepts of frequency response function (FRF) matrix and strain energy of a structure. The index is defined based on the change of strain energy of an element due to damage. For obtaining the strain energy stored in elements, the columnar coefficients of the FRF matrix is used. The new indicator is named here as frequency response function strain energy based index (FRFSEBI). In order to assess the performance of the proposed index for structural damage detection, some benchmark structures having a number of damage scenarios are considered. Numerical results demonstrate that the proposed index even with considering noise can accurately identify the actual location and approximate severity of the damage. In order to demonstrate the high efficiency of the proposed damage index, its performance is also compared with that of the flexibility strain energy based index (FSEBI) provided in the literature.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2011년도 추계학술발표대회
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• pp.351-354
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• 2011

This paper discusses on facial features extraction based on proposed skin color model. Different parts of face from input image are segmented based on skin color model. Moreover, this paper also discusses on concept to detect the eye and mouth position on face. A height and width ratio (${\delta}=1.1618$) based technique is also proposed to accurate detection of face region from the segmented image. Finally, we have cropped the desired part of the face. This exactly exacted face part is useful for face recognition and detection, facial feature analysis and expression analysis. Experimental results of propose method shows that the proposed method is robust and accurate.

• 대한전기학회논문지
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• 제36권9호
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• pp.678-684
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• 1987

The identification problem of instrument faults in PWR pressurizer is considered. The instrument failure detection technique in this paper consists of two filters, a normal-mode Kalman filter which estimates plant states in normal operation and a bias estimator which estimates the magnitudes and directions of bias faults. The concept of threshold based on the residual of a Kalman filter in normal operation is introduced. The bias estimator is driven when the absolute value of residual exceeds the threshold. The suggested failure detection algorithm is applied to a PWR pressurizer. Computer simulations show that the prompt detection of bias fault can be performed very successfully when there exist instrument faults.

• Computers and Concrete
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• 제2권6호
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• pp.481-498
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• 2005

A wavelet based approach is proposed for structural damage detection in beams, plate and delamination of composite plates. Wavelet theory is applied here for crack identification of a beam element with a transverse on edge non-propagating open crack. Finite difference method was used for generating a general displacement equation for the cracked beam in the first example. In the second and third example, damage is detected from the deformed shape of a loaded simply supported plate applying the wavelet theory. Delamination in composite plate is identified using wavelet theory in the fourth example. The main concept used is the breaking down of the dynamic signal of a structural response into a series of local basis function called wavelets, so as to detect the special characteristics of the structure by scaling and transformation property of wavelets. In the light of the results obtained, limitations of the proposed method as well as suggestions for future work are presented. Results show great promise of wavelet approach for damage detection and structural health monitoring.