• Journal of Computing Science and Engineering
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• 제5권1호
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• pp.19-31
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• 2011

In this paper, we propose two new routing schemes for double-layered peer-to-peer systems; a shorter-lower mobility routing scheme and a reverse path routing scheme. The shorter-lower mobility routing scheme first chooses shortest routing paths among possible routing paths and selects the path associated with the relay peer who has lower mobility to improve the reliability of the system. The reverse path routing scheme carries out unicasting (instead of multicasting) based on the reverse path information that can be obtained during the initial file search to further reduce network traffic. The experimental results showed that a double-layered peer-topeer system with the proposed hybrid scheme improved the reliability of the system about 1.5% over the hop count scheme and reduced network traffic by about 0.5% compared to the hop count scheme.

• 한국정밀공학회지
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• 제23권2호
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• pp.191-198
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• 2006

Dieless CNC forming is an innovative technology which can form various materials with complex shape by numerically controlled incremental forming process. In this paper, a method of NC tool path generation based on an STL file for dieless CNC forming is proposed. Tool trajectory adopts the principle of layered manufacturing in rapid prototyping technology, but it is necessary to consider STL offset because of the ball shaped tool with a radius. Vertex offset method which enables to compute offset STL directly is engaged for STL offset. The offseted STL is sliced by cutting planes to generate contouring tool path. Algorithm is implemented on a computer and experimented on a dieless CNC forming machine to show its validity.

• 한국정보통신학회논문지
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• 제11권7호
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• pp.1311-1317
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• 2007

최근 인터넷의 폭발적인 성장과 인기로 인하여, 인터넷상에서 정보의 교환이 매우 빠르게 증가하고 있다. 또한 XML은 인터넷상에서 정보교환의 수단인 동시에 표준으로서 자리를 잡아 가고 있다. 따라서 본 논문에서는 경로-지향 질의어를 평가하기 위한 새로운 인덱싱 기법과 사용자들에게 편리한 XML문서 검색 결과를 제공하기 위한 경로-지향 질의 처리 시스템의 설계 및 구현을 제공한다. 제안된 인덱싱 기법은 XML문서의 검색 성능을 향상시키기 위하여 이진 트라이 구조와 경로서명 파일을 결합하였다.

• 정보보호학회논문지
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• 제25권3호
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• pp.573-583
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• 2015

앰캐시(Amcache.hve) 파일은 프로그램 호환성 관리자(Program Compatibility Assistant)와 관련된 레지스트리 하이브 파일로 응용 프로그램의 실행정보를 저장한다. 이 파일을 통해서 응용 프로그램의 실행경로, 최초 실행시간을 확인할 수 있을 뿐 아니라, 삭제시간까지 추정할 수 있다. 응용 프로그램의 최초 설치시간 및 삭제시간까지 확인할 수 있기 때문에 프리패치(Prefetch) 파일, 아이콘캐시(Iconcache.db) 파일 분석과 병행하면 응용 프로그램의 전체적인 타임라인을 구성할 수 있다. 또한, 앰캐시 파일은 안티포렌식 프로그램, 포터블 프로그램 및 외장저장장치 흔적을 기록하고 있어 디지털 포렌식 관점에서 중요한 아티팩트이다. 본 논문에서는 앰캐시 파일의 특성과 응용 프로그램 삭제시간 추정 등 디지털 포렌식 기술로서의 활용방안을 제시한다.

• 농업과학연구
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• 제42권1호
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• pp.63-71
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• 2015

Path planning is an essential part for traveling and mowing of autonomous lawn mower tractors. Objectives of the paper were to analyze operation patterns by a skilled farmer, to extract and optimize waypoints, and to demonstrate generation of formatted planned path for autonomous lawn mower tractors. A 27-HP mower tractor was operated by a skilled farmer on grass fields. To measure tractor travel and operation characteristics, an RTK-GPS antenna with a 6-cm RMS error, an inertia motion sensing unit, a gyro compass, a wheel angle sensor, and a mower on/off sensor were mounted on the mower tractor, and all the data were collected at a 10-Hz rate. All the sensor data were transferred through a software program to show the status immediately on the notebook. Planned path was generated using the program parameter settings, mileage and time calculations, and the travel path was plotted using developed software. Based on the human operation patterns, path planning algorithm was suggested for autonomous mower tractor. Finally path generation was demonstrated in a formatted file and graphic display. After optimizing the path planning, a decrease in distance about 13% and saving of the working time about 30% was achieved. Field test data showed some overlap, especially in the turning areas. Results of the study would be useful to implement an autonomous mower tractor, but further research needs to improve the performance.

• International Journal of Precision Engineering and Manufacturing
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• 제4권5호
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• pp.27-33
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• 2003

G-code, another name of ISO6983, has been a popular commanding language for operating machine tools. This G-code, however, limits the usage of today's fast evolving high-performance hardware. For intelligent machines, the communications between machine and CAD/CAM departments become important, but the loss of information during generating G-code makes the production department isolated. The new standard for operating machine tools, named STEP-NC is just about to be standardized as ISO14649. As this new standard stores CAD/CAM information as well as operation commands of CNC machines, and this characteristic makes this machine able to exchange information with other departments. In this research, the new CNC machine operated by STEP-NC was built and tested. Unlike other prototypes of STEP-NC milling machines, this system uses the STEP-NC file in XML file form as data input. This machine loads information from XML file and deals with XML file structure. It is possible for this machine to exchange information to other databases using XML. The STEP-NC milling machines in this research loads information from the XML file, makes tool paths for two5D features with information of STEP-NC, and machines automatically without making G-code. All software is programmed with Visual $C^{++}$, and the milling machine is built with table milling machine, step motors, and motion control board for PC that can be directly controlled by Visual $C^{++}$ commands. All software and hardware modules are independent from each other; it allows convenient substitution and expansion of the milling machine. Example 1 in ISO14649-11 having the full geometry and machining information and example 2 having only the geometry and tool information were used to test the automatic machining capability of this system.

• 디지털콘텐츠학회 논문지
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• 제14권2호
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• pp.247-254
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• 2013

PRAM, FRAM, MRAM 등 스토리지 클래스 메모리(SCM)는 가까운 미래에 접근 속도는 DRAM에 용량은 플래시 메모리에 근접할 것으로 예상된다. 따라서 SCM이 컴퓨터 시스템에서 메모리(DRAM)뿐만 아니라 스토리지(하드디스크 혹은 플래시 메모리)를 대체할 수 있을 것이다. 이 논문에서는 SCM 기반 컴퓨터 시스템을 위한 효율적인 파일 접근 프레임워크를 제안한다. 제안하는 프레임워크는 SCM에 파일 저장을 위한 영역과 메모리 사용을 위한 영역을 구분하지 않는다. 또한 제안하는 프레임워크는 파일 관리를 위하여 단일 데이터 접근 경로, 파일 매핑을 통한 제로 카피 데이터 읽기, 카피 온 라이트 기반 데이터 쓰기, 다수 페이지 프리 폴팅 등 다양한 메모리 관련 기술들을 사용한다. 주요 실험 결과를 통해서 논문에서 제안하는 프레임워크는 SCM 기반 컴퓨터 시스템의 운영체제 디자인을 위한 초석이 될 것이다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1469-1473
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• 2004

We suggest how to program off-line robot path along shoes' outsole shape in the footwear buffing process by a 5-axis microscribe system like robot arms. This microscribe system developed consists a 5-axis robot link with a turn table, signal processing circuit, PC and an application software program. It makes a robot path on the shoe's upper through the movement of a microscribe with many joints. To do this, first it reads 5-encoder's pulse values while a robot arm points a shoes' outsole shape from the initial status. This system developed calculates the encoder pulse values for the robot arm's rotation and transmits the angle pulse values to the PC through a circuit. Then, Denavit-Hartenberg's(D-H) direct kinematics is used to make the global coordinate from robot joint one. The determinant is obtained with kinematics equation and D-H variable representation. To drive the kinematics equation, we have to set up the standard coordinates first. The many links and the more complicated structure cause the difficult kinematics problem to solve in the geometrical way. Thus, we can solve the robot's kinematics problems efficiently and systematically by Denavit-Hartenberg's representation. Finally, with the coordinate values calculated above, it can draw a buffing gauge-line on the upper. Also, it can program off-line robot path on the shoes' upper. We are subjected to obtaining shoes' outline points, which are 2 outlines coupled with the points and the normal vector based on the points. These data is supposed to be transformed into .dxf file to be used for data of automatic buffing robot. This system developed is simulated by using spline curves coupled with each point from dxf file in Autocad. As a result of applying this system to the buffing robot in the flexible footwear manufacturing system, it can be used effectively to program the path of a real buffing robot.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제4권5호
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• pp.799-818
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• 2010

In traditional unstructured P2P file sharing network, each peer establishes connections with a certain number of randomly chosen other peers. This would lead to redundant traffic and P2P network partition in mobile ad hoc network (MANET). We propose an approach to construct an efficient unstructured P2P overlay over MANET using underlying cluster-based routing (CBRP). One of the peers in the P2P network is used as a root-peer to connect all peers. Each peer maintains connection with physically closer peers such that it can reach the root-peer. The peer constructs a minimum-spanning tree consisting of itself, its directly connected neighbor peers and 2-hop away neighbor peers to remove far away redundant links and to build an overlay closer to the physical network. Due to on-demand nature of inter-cluster routing of CBRP, the positioning algorithm for MANET is used to retrieve the file by a peer from the source peer via shorter path in the physical network. We can show by simulation that our approach performs better in comparison with the existing approach.

• 융합보안논문지
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• 제13권4호
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• pp.109-115
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• 2013

인터넷망을 이용한 정보 전달의 대표적인 수단인 이메일 서비스 등을 통한 보안위협이 급증하고 있다. 이러한 보안위협의 공격 경로는 첨부된 문서파일에 악성코드를 삽입하고, 해당 응용프로그램의 취약점을 이용하여 사용자의 시스템을 감염시키게 된다. 따라서 본 연구에서는 파일 전송과정에서 위장악성코드의 감염을 차단하기 위해, 논리적 망 분리인 FTS(File Transfer System)를 이용한 무결성 검증 및 행위기반 탐지 시스템을 제안하고, 기존의 보안기법과의 비교 및 검증하고자 한다.