• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.8
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• pp.847-853
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• 2011

Filiform hairs that respond to movements of the surrounding medium are the mechanoreceptors commonly found in arthropods and vertebrates. The hairs function as a sensory system for perceiving information produced by prey, predators, or conspecifics. A mathematical model is proposed, and the parametric analyses for the response of artificial filiform hair are conducted to design and predict the performance of a microfabricated device. The results for the Cytop hair, one of the most popular polymer optical fibers (POFs), show that the fundamental mode has a dominant effect on the hair behavior in an oscillating medium flow. The dynamic behavior of sensory hair is also dependent on the physical dimensions such as length and diameter. It is found that the artificial hair with a high elastic modulus does not show a resonance in the biologically important frequency range.

• Convergence Security Journal
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• v.9 no.4
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• pp.7-12
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• 2009

It is very difficult to completely block the DDoS attack, which paralyzes services by depleting resources or occupying the network bandwidth by transmitting a vast amount of traffic to the specific website or server from normal users' PCs that have been already infected by an outside attacker. In order to defense or endure the DDoS attack, we usually use various solutions such as IDS (Intrusion Detection System), IPS (Intrusion Prevention System), ITS (Intrusion Tolerance System), FW (Firewall), and the dedicated security equipment against DDoS attack. However, diverse types of security appliances cause the cost problem, besides, the full function of the equipments are not performed well owing to the unproper setting without considering connectivity among systems. In this paper, we present the effective connectivity of security equipments and countermeasure methodology against DDoS attack. In practice, it is approved by experimentation that this designed methdology is better than existing network structure in the efficiency of block and endurance. Therefore, we would like to propose the effective security control measures responding and enduring against discriminated DDoS attacks through this research.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.9
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• pp.614-619
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• 2014

In WSN (Wireless Sensor Networks) based surveillance system, it needs to know the occurrence of events or objects and their locations, because the data have no meaning without location information. Using traditional 2D localization mechanisms provide good accuracy where altitude is fixed. But the mapping the position estimated by 2D localization to the real world can cause an error. Even though 3D localization mechanisms provide better accuracy than 2D localization, they need four reference nodes at least and high processing overhead. In our surveillance system, it is needed to estimate the height of the detected object in order to determine if the object is human. In this paper, we propose a height estimation mechanism which does not require many reference nodes and high complexity. Finally, we verify the performance of our proposed mechanism through various experiments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.5
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• pp.985-990
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• 2007

The method of enhancing visibility in optical fiber sensor was investigated by improving coherence length of light source. The optical feedback technique is used to enhance coherence length in fiber laser which generates laser in near infrared wavelength region and utilizes low loss characteristics of optical communication grade fiber. In this paper, the effect to coherence length by short and long optical feedback paths are investigated by using Mach-Zehnder interferometer technique. The effect to coherence length by changing optical feedback power and optical modulation are investigated. The spectral drift was calculated by measuring the degree of phase perturbation in unbalanced Mach-Zehnder interferometer having loom path difference. The short optical feedback path was effective to reduce spectral drift to 450kHz/sec and the long optical feedback path in combination with short optical feedback path was found to further reduce spectral drift to 50kHz/sec.

• Journal of Convergence for Information Technology
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• v.8 no.6
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• pp.143-148
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• 2018

In this paper, we propose a personalized user authentication system (PUAS) that can be used in multiple stages in user authentication by customizing the password keyword to be used in user authentication. The proposal concept is that the user oneself defines the password keyword to be used in user authentication so as to cope with a passive retransmission attack which reuses the password obtained when the server system is accessed in user authentication. The authentication phase is also designed so that it can be expanded in multiple stages in a single step. Also, it is designed to store user-defined password related information in an arbitrary encrypted place in the system, thereby designing to disable the illegal access of the network. Therefore, even if an intruder accesses the system using the proposed system, it is possible to generate personal authentication information by generating a password keyword through unique personal information possessed only by an individual and not know the place where the generated authentication information is stored, It has a strong security characteristic.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.10
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• pp.1262-1270
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• 2020

Recently, the smart video surveillance research, which has been receiving increasing attention, has mainly focused on the intruder detection and tracking, and abandoned object detection. On the other hand, research on real-time detection of stolen objects is relatively insufficient compared to its importance. Considering various smart surveillance video application environments, this paper presents two different types of stolen object detection algorithms. We first propose an algorithm that detects theft of statically and dynamically registered surveillance objects using a dual background subtraction model. In addition, we propose another algorithm that detects theft of general surveillance objects by applying the dual background subtraction model and Mask R-CNN-based object segmentation technology. The former algorithm can provide economical theft detection service for pre-registered surveillance objects in low computational power environments, and the latter algorithm can be applied to the theft detection of a wider range of general surveillance objects in environments capable of providing sufficient computational power.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.3
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• pp.135-144
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• 2003

An intrusion detection system shows different result over overall detection area according to its detection characteristics of inner detection algorithms or techniques. To expand detection areas, we requires an integrated detection which can be archived both by deploying a few detection systems which detect different detection areas and by combining their results. In addition to expand detection areas, we need to decrease the workload of security managers by false alarms and improve the correctness by minimizing false alerts which happen during the process of integration. In this paper, a method for aggregation detection use fuzzy inference to integrate a vague detection results which imply the characteristics of detection systems. Their analyzed detection characteristics are expressed as fuzzy membership functions and fuzzy rule bases which are applied through the process of fuzzy control. And, it integrate a vague decision results and minimize the number of false alerts by reflecting the characteristics of detection systems. Also it does minimize inference objects by applying thresholds decided through several experiments.

• Journal of the Institute of Convergence Signal Processing
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• v.22 no.1
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• pp.1-6
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• 2021

Recently, unmanned facilities have been introduced and operated in a way that reduces the cost and development of IT technology. Although unmanned facilities have advantages in terms of efficiency and economy, they have disadvantages such as failure of unmanned facilities and malfunctions, causing damage to facilities caused by intruders, and information leakage. In addition, it is necessary to visit the person in charge at all times to inspect the unmanned facilities, resulting in management costs. In this paper, we designed a system that checks the status of unmanned surveillance facilities in real time to check and automatically recover problems such as malfunctions, and to notify managers of situations by text messages in real time. The system to be designed consists of an integrated network video server (NVR) that receives and determines information on the operation status of the main equipment such as video, sound, and lighting, and a real-time text message using an SMS server.

• Landscaping Tree
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• s.102
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• pp.26-28
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• 2008

최근 환경변화와 국제교류의 확대로 인하여 예전에는 문제가 되지 않았거나, 보이지 않았던 해충들이 문제해충화 되어 우리 주변에서 정원수나 조경수에 피해를 주는 해충들이 있다. 이들은 크게 3가지로 분류되는데 (1)환경의 변화에 의한 잠재해충과 문제해충화 (2) 인간의 욕심에 의해 대면적 식재로 인한 해충의 기회 확대 (3) 국제교류 확대로 인한 외래 해충의 침입 으로 나눌 수 있다. 이번 호에서는 환경변화에 의한 해충의 발생으로 환경스트레스에 의해 식물 자체 내의 방어체계가 무너지면 어떤 특정종이나 일반 해충이 대발생하는데 식물자체 환경 스트레스에 관계하는 jasmonate의 작용 저해, 식물이 자기방어를 위해 분비하는 타감물질(allelopathy)의 분비 억제, 초식성 곤충으로부터 산란억제를 위한 연모의 부족 등 해충의 대발생을 야기 시키는 경우도 있다. 또한 지구온난화로 인한 각종 해충의 대발생은 현재 전 세계적으로 문제가 되고 있다. 기온의 상승으로 곤충의 발육이 빨라져 화기 수가 증가한다거나, 포식자와 피식자의 상호작용의 연결고리가 깨어지는 등 각종 원인으로 인한 최근 발생한 해충을 기술하였다.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2002.11a
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• pp.161-165
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• 2002

최근 증가하고 있는 인터넷 및 기타 네트워크 시스템에 대한 위협은 그 공격의 목적과 기법, 피해의 종류가 늘어남에 따라 효과적인 대응책으로 단순한 기술적 접근 이외에 법률 및 심리, 사회 공학적 접근의 결합적인 대처방안이 강구되어야 할 것이다. 이를 효과적으로 보조할 수 있는 시스템이 Honeypot이다. 하지만 Honeypot 자체는 공격의 위협을 그 즉시 막는데는 별다른 능력이 없기 때문에 Honeypot 시스템의 의도대로 공격자가 속지 않거나 Honeypot의 정보가 다른 보안 도구와 보안 정책 갱신에 이용되기 이전의 공격에 대해서는 취약점을 가지고 있다. 이에 따라 본 논문에서는 기존의 Honeypot이 설치된 시스템의 효과적 활용을 위해 신경망 이론에 기반한 침입 탐지 모듈을 연동하며 이를 통해 초기 공격에 대한 Honeypot 시스템 보호, Honeypot 시스템이 활성화 된 다음의 상호 연동 효과 및 향후 과제 등을 기술한다. 또한 이에 대한 보다 확실한 접근을 위해 Honeypot 시스템을 통해 DDoS를 방어하도록 제안되었던 시스템의 취약점과 이를 효과적으로 해결할 수 있는 방법을 제안한다.