• 융합보안논문지
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• 제16권7호
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• pp.61-68
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• 2016

국네트워크를 통한 데이터의 공유로 인해 각종 분야에서 첨단 응용 연구 성과를 보여 왔다. 그만큼 이에 적합한 안정적 데이터 공유 환경의 필요성 역시 꾸준히 제기되었다. 본 연구에서는 이러한 필요성에 따라 등장한 여러 성과 중 일방향 통신 지향 프로토콜에 대해 다룬다. 이 프로토콜은 오직 일방향만으로 데이터를 전송토록 하는 체계이다. 이는 불확실하고 잠재적인 위협 요소로부터 시스템을 지켜낼 가능성이 높아지지만, 데이터에 대한 확인/응답(ACK) 패킷을 전혀 받을 수 없다. 따라서 TCP, ICMP와 같은 양방향 프로토콜이 제대로 작동하면서 실질적인 통신이 이루어지도록 해야 한다. 이에 따라 본 연구에서는 인터페이스 계층, 인터넷 계층, 전송 계층에 대해서 각각 존재하는 프로토콜별 가능한 시나리오에 대해 분석하고 각각의 해결방법에 대해 접근하였다.

• 한국전자파학회논문지
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• 제22권1호
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• pp.24-29
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• 2011

네트워크 부호화를 이용한 양 방향 중계 기법은 기존의 단 방향 중계 프로토콜보다 송신 시간을 줄임으로써 전송량을 높일 수 있는 장점을 가지며, 부호화 협력 프로토콜은 물리층에서 이루어지는 부호화를 적용한 알고리즘으로 프로토콜의 신뢰성을 높일 수 있는 장점을 가진다. 본 논문에서는 이러한 두 프로토콜의 장점을 결합한 양 방향 중계 네트워크에서의 부호화 협력 프로토콜을 제안하였다. 제안하는 프로토콜이 기존의 양 방향 증폭후 재전송 프로토콜보다 우수한 신뢰성과 전송량을 가지며, 기존의 양 방향 하이브리드 복호 후 재전송 프로토콜과 동일한 전송량을 가지면서 보다 우수한 신뢰성을 가짐을 시뮬레이션 결과를 통해 증명한다.

• 정보보호학회논문지
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• 제27권5호
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• pp.1129-1140
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• 2017

물리적 단방향 송신만을 허용하는 단방향 전송 시스템은 백워드 링크를 물리적으로 제거하여 외부에서 네트워크를 통한 침입을 원천 차단한다. 이러한 단방향 전송 시스템은 역방향 송신 또는 양방향 통신이 필요한 환경에서는 적용하기 어렵다. 본 논문에서는 outbound TCP 양방향 통신을 허용하는 제한적 양방향 통신 시스템(LimTway, Limited Two-way communications system)을 제안한다. LimTway는 포워드 및 백워드 단방향 링크를 사용하며, 포워드 단방향 링크는 outbound UDP 트래픽의 단방향 송신을 위해 항상 활성화 상태로 유지되는 반면, 백워드 단방향 링크는 허용된 outbound TCP 세션이 설립된 동안만 활성화된다. 백워드 단방향 링크가 활성화 상태인 기간 동안 발생할 수 있는 외부로부터의 침입을 차단하기 위해, outbound TCP 트래픽 및 outbound UDP 단방향 트래픽만을 허용하도록 소프트웨어를 설계하였다.

• 대한임베디드공학회논문지
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• 제5권4호
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• pp.234-242
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• 2010

Two-way ranging methods such as TWR and SDS-TWR have been considered for many ranging systems because these methods are useful in the absence of synchronization. To estimate the location of a mobile node, complicated ranging procedures consisting of ranging frames between an anchor node and the mobile node are performed. Supporting multiple mobile nodes such as a few hundreds or thousands and several anchor nodes, the ranging procedures have the fatal disadvantage of processing delay and inefficient traffic bandwidth. On the other hand, the one-way ranging method is simple and fast, but susceptible to network synchronization. In this paper, we propose a method to modify asynchronous ranging equations to establish exact frequency or frequency offset, a method to estimate frequencies or frequency offsets, and a method to establish post-facto synchronization with anchor nodes. The synchronization for a node pair is adapted using instantaneous time information and corresponding difference of distances can be determined. We evaluate the performance of TWR, SDS-TWR and proposed ranging algorithms.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2016년도 제54차 하계학술대회논문집 24권2호
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• pp.51-54
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• 2016

In computer vision especially in image processing, it has become popular to apply deep convolutional networks for supervised learning. Convolutional networks have shown a state of the art results in classification, object recognition, detection as well as semantic segmentation. However, supervised learning has two major disadvantages. One is it requires huge amount of labeled data to get high accuracy, the second one is to train so much data takes quite a bit long time. On the other hand, unsupervised learning can handle these problems more cheaper way. In this paper we show efficient way to learn features for classification in an unsupervised way. The network trained layer-wise, used backpropagation and our network learns features from unlabeled data. Our approach shows better results on Caltech-256 and STL-10 dataset.

• 항공우주시스템공학회지
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• 제14권6호
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• pp.26-35
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• 2020

The national satellite operation network, which supports multiple satellites, was designated as a Critical Information Infrastructure (CII) in 2017. The network was designed independently from the control network and the information network to enhance physical security. Planning is underway to establish a bidirectional data interface between networks. The data transmission system allows data flow only to the physical layer and the data link layer; hence, only one file can be transferred at any one time. This means that when large amounts of data are being transmitted, no other data can be sent simultaneously in urgent situations. Thus, this paper discusses the design of flexible packets for the transmission of data between networks in an environment where physical security has been enhanced through network separation and based on this, presents a method for transmitting data effectively.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1602-1605
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• 2005

An audit tracer is one of the last ways to defend an attack for network equipments. Firewall and IDS which block off an attack in advance are active way and audit tracing is passive way which analogizes a type and a situation of an attack from log after an attack. This paper explains importance of audit trace function in network equipment for security and defines events which we must leave by security audit log. We design and implement security audit system for secure router. This paper explains the reason why we separate general audit log and security audit log.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.270-273
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• 1999

This paper describes the characteristics of two methods about providing information needed for propulsion device control in train. The one is to use new way using the communication network for transmission of control information, the other is traditional way using hardwire connection. And this paper describes the communication interface technique between TCMS(Train Control and Monitoring System) and VVVF inverter system with LonWorks network adapted to SMG line 6 which has been developed. With this technique, an inertia load test carried out for the traction control environment and it is expecting a field test at SMG line 6.

• 제어로봇시스템학회논문지
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• 제19권2호
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• pp.125-130
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• 2013

Compared to OWR (One-Way Ranging) method that requires precise network time synchronization, TWR (Two-Way Ranging) method has advantages in building an indoor WPAN (Wireless Personal Area Network) location system with lower cost. However, clock offsets of nodes in WPAN system should be eliminated or compensated to improve location accuracy of the TWR method. Because conventional clock offset elimination methods requires multiple TWR transactions to reduce clock offset, they produce network traffic burden instead. This paper presents a clock offset estimation method that can reduce clock offset error with a single TWR transaction. After relative clock offsets of sensor nodes are estimated, clock offsets of mobile tags are estimated using a single TWR communication. Simulation results show that location accuracy of the proposed method is almost similar to the conventional clock offset elimination method, while its network traffic is about a half of the conventional method.

• 산업공학
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• 제14권1호
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• pp.30-38
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• 2001

Logistics network management has become one of the most important sources of competitive advantage regarding logistics cost and customer service in numerous business segments. Logistics network simulation is a powerful analysis method for designing and planning the logistics network optimally in an integrated way. This paper introduces a logistics network simulator, LONSIM, developed by author. LONSIM deploys a mix of simulation and optimization functions to model and analysis logistics network issues such as facility location, inventory policy, manufacturing policy, transportation mode, warehouse assignment, supplier assignment, order processing priority rule, and vehicle routes. LONSIM is built with AweSim 2.1 and Visual Basic 6.0, and executed in windows environment.