• 한국사이버테러정보전학회:학술대회논문집
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• 한국사이버테러정보전학회 2004년도 제1회 춘계학술발표대회
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• pp.233-239
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• 2004

본 논문에서는 현재 네트워크 환경에서 Stepping Stones을 이용한 경유지 우회 공격에 대한 침입자 추적 메커니즘을 제안한다. 침입자는 피해시스템에서 공격자의 IP주소 노출을 피하기 위하여 피해시스템을 직접 공격하지 않고 Stepping stone을 이용하여 경유지 우회 공격을 수행한다. 우리는 이와 같은 경유지 우회 공격 발생 시 공격자의 IP주소의 추적을 목적으로 한다. 침입자 추적은 크게 두 가지 분류로 나뉘어 진다. 첫째는 IP Packet traceback, 둘째는 Connection traceback 이다. 본 논문에서는 Connection traceback에 공격을 다루며, 운영체제의 프로세스 구조를 이용하여 공격자 또는 Stepping stone(경유지)을 구분하여 침입자의 위치를 추적한다.

• 한국군사과학기술학회지
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• 제17권3호
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• pp.358-363
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• 2014

In this paper, we present two constructions of the attribute-based broadcast encryption(ABBE) algorithm. Attribute-based encryption(ABE) algorithm enables an access control mechanism over encrypted data by specifying access policies among private keys and ciphertexts. ABBE algorithm can be used to construct ABE algorithm with revocation mechanism. Revocation has a useful property that revocation can be done without affecting any non-revoked uers. The main difference between our algorithm and the classical ones derived from the complete subtree paradigm which is apt for military hierarchy. Our algorithm improve the efficiency from the previously best ABBE algorithm, in particular, our algorithm allows one to select or revoke users by sending ciphertext of constant size with respect to the number of attributes and by storing logarithm secret key size of the number of users. Therefore, our algorithm can be an option to applications where computation cost is a top priority and can be applied to military technologies in the near future.

• 한국광학회지
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• 제26권4호
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• pp.187-194
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• 2015

비정형(anamorphic) 렌즈가 적용된 적외선 광각 카메라 광학계를 제안하고 제작을 통해 그 유용성을 입증하였다. 개발된 적외선 카메라는 비정형 렌즈를 이용하여 수평방향에 대해서는 100도 이상의 넓은 시계를 제공하면서 수직방향에 대해서는 수평시계보다 큰 배율을 갖게 함으로써 증가된 해상도를 통해 장비의 광역 감시 및 탐지 능력을 동시에 향상시키는 특징을 갖는다. 또한 광기구적 자동 비열화 방법을 제안하고 시스템에 적용하여 그 성능 및 활용성을 확인하였다.

• BMB Reports
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• 제37권6호
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• pp.735-740
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• 2004

Hepatitis C virus (HCV) is a causal agent of the chronic liver infection. To understand HCV morphogenesis, we studied the assembly of HCV structural proteins in insect cells. We constructed recombinant baculovirus expression vectors consisting of either HCV core alone, core-E1, or core-E1-E2. These structural proteins were expressed in insect cells and were examined to assemble into particles. Neither core-E1 nor core-E1-E2 was capable of assembling into virus-like particles (VLPs). It was surprising that the core protein alone was assembled into core-like particles. These particles were released into the culture medium as early as 2 days after infection. In our system, HCV structural proteins including envelope proteins did not assemble into VLPs. Instead, the core protein itself has the intrinsic capacity to assemble into amorphous core-like particles. Furthermore, released core particles were associated with HCV RNA, indicating that core proteins were assembled into nucleocapsids. These results suggest that HCV may utilize a unique core release mechanism to evade the hosts defense mechanism, thus contributing to the persistence of HCV infection.

• 대한물리치료과학회지
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• 제9권1호
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• pp.153-158
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• 2002

Pain, which is the most significant issue for the physical therapist, is the cause of various diseases until it disappears, and results in a lot of obstructions to treatment. Pain is very complicated. It is a subjective symptom that informs of a pathologic condition in the body, and one of the unpleasant experiences that people have. It is accompanied with anxiety and fear. Many researchers including Krause(1987) have identified the pain mechanism based on pain perception for many centuries and they have suggested many theories as they believed that pain management was possible. Reviewing the contents of psychoanalysis, uncontrollable pain that can't be explained is described as a defense mechanism to an unconscious psychological conflict. That is, mental pain is transferred to the body and the pain becomes unbearable. What is important is, like Keefe(1992) said, that the pain experience itself is primary stress and one should cope with it, whatever the cause of the pain. This paper investigates the background of the psychological theory of pain. Based on the efforts of previous studies, the next research generation will understand the treatment process for pain more dearly and will contribute to the prevention and protection from pain that humans undergo.

• International Journal of Aeronautical and Space Sciences
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• 제16권1호
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• pp.50-63
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• 2015

Explosive bolts are one of pyrotechnic release devices, which are highly reliable and efficient for a built-in release. Among them, ridge-cut explosive bolts which utilize shock wave generated by detonation to separate bolt body produce minimal fragments, little swelling and clean breaks. In this study, separation phenomena of ridge-cut explosive bolts or ridge-cut mechanism are computationally analyzed using Hydrocodes. To analyze separation mechanism of ridge-cut explosive bolts, fluid-structure interactions with complex material modeling are essential. For modeling of high explosives (RDX and PETN), Euler elements with Jones-Wilkins-Lee E.O.S. are utilized. For Lagrange elements of bolt body structures, shock E.O.S., Johnson-Cook strength model, and principal stress failure criteria are used. From the computational analysis of the author's explosive bolt model, computational analysis framework is verified and perfected with tuned failure criteria. Practical design improvements are also suggested based on a parametric study. Some design parameters, such as explosive weights, ridge angle, and ridge position, are chosen that might affect the separation reliability; and analysis is carried out for several designs. The results of this study provide useful information to avoid unnecessary separation experiments related with design parameters.

• 한국식물학회:학술대회논문집
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• 한국식물학회 1999년도 제13회 식물생명공학심포지움 New Approaches to Understand Gene Function in Plants and Application to Plant Biotechnology
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• pp.79-84
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• 1999

Oxidative stress is one of the major environmental stresses to plants. Reactive oxygen species (ROS) generated during metabolic processes damage cellular functions and consequently lead to cell death. Fortunately plants have in vivo defense system by which the ROS is scavenged by enzymes such as superoxide dismutase (SOD) and ascorbate peroxidase (APX). In attempts to understand the protection mechanism of plant against oxidative stress, we developed transgenic tobacco (Nicotiana tabacum cv. Xanthi) plansts thet expressed both SOD and APX in chloroplast using Agrobacterum-mediated transformation and evaluated their protection capabilities against methyl viologen (MV, paraquat) -mediated oxidative damage. Three double transformants (CAI, CA2, and CA3) expressed the chimeric CuZnSOD and chimeric APX in chloroplast, and one transformant (AM) expressed the chimeric APX and chimeric MnSOD in chloroplast. In addition, we obtained three lines of transformants (C/Al, C/A2, and A/C) that expressed the APX and SOD than control plants, and more resistant to oxidative stress caused by MV. TRansformants (C/A and A/C) overexpressing MnSOD, CuZnSOD and APX at the same time showed the highest resistance to MV-mediated oxidative stress among the transformants.

• Biomolecules & Therapeutics
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• 제29권4호
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• pp.353-364
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• 2021

The gastrointestinal (GI) tract is a series of hollow organs that is responsible for the digestion and absorption of ingested foods and the excretion of waste. Any changes in the GI tract can lead to GI disorders. GI disorders are highly prevalent in the population and account for substantial morbidity, mortality, and healthcare utilization. GI disorders can be functional, or organic with structural changes. Functional GI disorders include functional dyspepsia and irritable bowel syndrome. Organic GI disorders include inflammation of the GI tract due to chronic infection, drugs, trauma, and other causes. Recent studies have highlighted a new explanatory mechanism for GI disorders. It has been suggested that autophagy, an intracellular homeostatic mechanism, also plays an important role in the pathogenesis of GI disorders. Autophagy has three primary forms: macroautophagy, microautophagy, and chaperone-mediated autophagy. It may affect intestinal homeostasis, host defense against intestinal pathogens, regulation of the gut microbiota, and innate and adaptive immunity. Drugs targeting autophagy could, therefore, have therapeutic potential for treating GI disorders. In this review, we provide an overview of current understanding regarding the evidence for autophagy in GI diseases and updates on potential treatments, including drugs and complementary and alternative medicines.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제18권6호
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• pp.1431-1448
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• 2024

Complexity science is a new stage in the development of systems science that is the frontier areas of contemporary scientific development. Complexity science takes complex systems as the research object, which has attracted widespread attention from researchers in the fields of economy, control, management, and society. In recent years, with the rapid development of science and technology and people's deepening understanding for the theory of complex systems, the systems are no longer an object with a single function, but the systems are composed of multiple individuals with autonomous capabilities through cooperative and cooperation, namely multi-agent system (MAS). Currently, MAS is one of the main models for studying such complex systems. The intelligent control is to break the traditional multi-agent fault-tolerant control (FTC) concept and produce a new type of compensation mechanism. In this paper, the applications of fault-tolerant control methods for MASs are presented, and a discussion is given about development and challenges in this field.

• Current Optics and Photonics
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• 제8권5호
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• pp.463-471
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• 2024

Multimode fibers (MMFs) possess high information throughput and small core diameter, making them highly promising for applications such as endoscopy and communication. However, modal dispersion hinders the direct use of MMFs for image transmission. By training neural networks on time-series waveforms collected from MMFs it is possible to reconstruct images, transforming blurred speckle patterns into recognizable images. This paper proposes a fully convolutional neural-network model, MSMDFNet, for image restoration in MMFs. The network employs an encoder-decoder architecture, integrating multiscale convolutional modules in the decoding layers to enhance the receptive field for feature extraction. Additionally, attention mechanisms are incorporated from both spatial and channel dimensions, to improve the network's feature-perception capabilities. The algorithm demonstrates excellent performance on MNIST and Fashion-MNIST datasets collected through MMFs, showing significant improvements in various metrics such as SSIM.