• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.3
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• pp.991-996
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• 2010

In this paper, we designed a parallel I/O control system using IEEE 1284 operating modes and implemented remote control communication under the internet environment. The IEEE 1284 standard defines an interface compatible with several distinct operation modes and brings higher performance to the PC parallel port. Therefore, parallel port devices become easier to configure and simplify interface because new operating systems bring PnP function to the parallel port with the Device/ID identification sequence. With these enhancements, the parallel port become an even better low-cost, readily available I/O port on the PC.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04a
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• pp.636-638
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• 2000

가장 느린 서비스시템인 I/O의 성능이 전체적인 컴퓨터 시스템의 성능을 결정짓게 된다. 따라서 전반적인 시스템의 성능 향상을 위해서는 I/O의 성능이 높아져야 한다. 분산병렬환경에서 I/O의 성능을 높이기 위해서 parallel I/O를 사용한다. 하위레벨에서 최적화된 병렬 파일시스템을 사용하고, 어플리케이션 레벨에서 병렬 에플리케이션의 개발을 쉽게 해줄 수 있는 인터페이스를 사용하면 더 효과적인 parallel I/O를 구현할 수 있다. 본 논문에서는 MPI에서 병렬 파일시스템인 CrownFS를 지원하도록 하기 위해서 MPI-IO에 CrownFS를 추가하여 병렬환경에서 높은 성능을 나타낼수 있는 parallel I/O 환경을 구현한다.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10b
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• pp.117-119
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• 1998

대용량의 데이터를 다루는 지리정보 시스템은 I/O가 시스템의 병목현상을 발생시킨다. 따라서, I/O의 병렬화로 GIS의 데이터 요구를 만족시키려는 연구가 이루어져 왔다. PR(Parallel R-tree)[1]도 이러한 연구에 속한다. 한편, 지리 정보 시스템의 질의는 영역질의가 대부분이다. 영역질의는 특성상 인접한 객체들의 동시에 요구한다. 그러므로, 인접한 데이터를 물리적으로 인접하게 배치하면 I/O의 성능이 향상된다. 본 논문에서는 인접한 객체를 물리적으로 인접한 위치에 저장하는 방식인 EPR(Enhanced PR)기법과 단말노드 구조를 제안하고 그 성능을 평가하였다.

• Journal of Industrial Technology
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• v.21 no.A
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• pp.97-103
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• 2001

This paper presents the development of the I/O Interface for the real time parallel data communication between controller of a six-axis industrial robot(CRS-A460) and an external computer. The proposed I/O Interface consists of the hardware I/O interface and the software that is downloaded to the robot controller and executed by the controller operating system. The constitution of the digital I/O Port for CRS-A460 robot controller and the digital I/O board for IBM-PC are presented as well as the Process Control Program of the robot controller. The developed protocol for the parallel data communication is described. The data communication is tested, and the performance is analysed. In particular, it is shown that the real-time constraint of the robot controller process is satisfied.

• Journal of Internet Computing and Services
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• v.18 no.2
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• pp.53-60
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• 2017

Since processors are handling inputs and outputs independently on distributed memory computers, different file input/output methods are used. In this paper, we implemented and compared various file I/O methods to show their efficiency on distributed memory parallel computers. The implemented I/O systems are as following: (i) parallel I/O using NFS, (ii) sequential I/O on the host processor and domain decomposition, (iii) MPI-IO. For performance analysis, we used a separated file server and multiple processors on one or two computational servers. The results show the file I/O with NFS for inputs and sequential output with domain composition for outputs are best efficient respectively. The MPI-IO result shows unexpectedly the lowest performance.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.513-516
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• 2007

Because many scientific applications require large data processing, the importance of parallel I/O has been increasingly recognized. Collective I/O is one of the considerable features of parallel I/O and enables application programmers to easily handle their large data volume. In this paper we measure and analyze the performance of original collective I/Os and the subgroup method, the way of using collective I/O of MPI effectively. From the experimental results, we found that the two kinds of subgroup method showed different performance. In terms of collective write operation, the subgroup method caused the performance degradation. However, the subgroup method for collective read showed good performance with small data size.

• Proceedings of the KIEE Conference
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• 1998.07g
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• pp.2327-2329
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• 1998

In this paper, an algorithm to make a configuration system for managing the I/O device of programmable logic controller(PLC) is proposed. Parallel processing architecture is used to deal with a number of I/O devices. From that architecture, a contention problem between processors can arise. To resolve this problem, the configuration system that contains informations about I/O devices is introduced. This configuration system is used to check the contention between processors in the I/O device and also used in program execution.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.37-38
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• 2017

최근 방제 및 예찰과 같은 농작업에 단일 UAV(Unmanned Aerial Vehicle)시스템이 적용되고 있지만, 가반하중과 체공시간 등 기존시스템의 문제가 점차 대두되면서 작업 시간을 보다 단축시키고 작업 효율을 극대화 할 수 있는 농업용 멀티 UAV시스템의 필요성이 증대되고 있다. 본 논문에서는 작업자가 다수의 농업용 UAV를 효과적으로 제어할 수 있는 분산군집제어 알고리즘을 제안하며 알고리즘 검증 및 평가를 위한 시뮬레이터를 소개한다. 분산군집제어는 UAV 제어 계층, VP(Virtual Point) 제어 계층, 원격제어 계층으로 이루어진 3계층 제어구조를 가진다. UAV 제어 계층에서 각 UAV는 point mass로 모델링 되는 VP의 이상적인 경로를 추종하도록 제어한다. VP 제어 계층에서 각 VP는 입력 $p_i(t)=u^c_i+u^o_i+u^{co}_i+u^h_i$-(1)을 받아 제어되는데 여기서, $u^c_i{\in}{\mathbb{R}}^3$는 VP 사이의 충돌방지제어, $u^o_i{\in}{\mathbb{R}}^3$는 장애물과의 충돌방지제어, $u^{co}_i{\in}{\mathbb{R}}^3$는 UAV 상호간의 협조제어, $u^h_i{\in}{\mathbb{R}}^3$는 작업자로부터의 원격제어명령이다. (1)의 제어입력에서 충돌방지제어는 각 $u^i_c:=-{\sum\limits_{j{\in}{\eta}_i}}{\frac {{\partial}{\phi}_{ij}^c({\parallel}p_i-p_j{\parallel})^T}{{\partial}p_i}}$-(2), $u^o_c:=-{\sum\limits_{r{\in}O_i}}{\frac {{\partial}{\phi}_{ir}^o({\parallel}p_i-p^o_r{\parallel})^T}{{\partial}p_i}}$-(3)로 정의되면 ${\phi}^c_{ij}$와 ${\phi}^o_{ir}$는 포텐셜 함수를 나타낸다. 원격제어 계층에서 작업자는 햅틱 인터페이스를 통해 VP의 속도를 제어하게 된다. 이때 스케일변수 ${\lambda}$에 대하여 VP의 원격제어명령은 $u^t_i(t)={\lambda}q(t)$로 정의한다. UAV 시뮬레이터는 리눅스 환경에서 ROS(Robot Operating Systems)를 기반한 3차원 시뮬레이터인 Gazebo상에 구축하였으며, 마스터와 슬레이브 간의 제어 명령은 TCPROS를 통해 서로 주고받는다. UAV는 PX4 기반의 3DR Solo 모델을 사용하였으며 MAVROS를 통해 MAVLink 통신 프로토콜에 접속하여 UAV의 고도, 속도 및 가속도 등의 상태정보를 받을 수 있다. 현재 멀티 드론 시스템을 Gazebo 환경에 구축하였으며, 추후 시뮬레이터 상에 분산군집제어 알고리즘을 구현하여 검증 및 평가를 진행하고자 한다.

• ETRI Journal
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• v.20 no.4
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• pp.301-326
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• 1998

In this paper, we have modeled and evaluated a new parallel processing system called Scalable Parallel computer Architecture based on Xbar (SPAX) for commercial applications. SMP systems are widely used as servers for commercial applications; however, they have very limited scalability. SPAX cost-effectively overcomes the SMP limitation by providing both scalability and application portability. To investigate whether the new architecture satisfies the requirements of commercial applications, we have built a system model and a workload model. The results of the simulation study show that the I/O subsystem becomes the major bottleneck. We found that SPAX can still meet the I/O requirement of the OLTP workload as it supports flexible I/O subsystem. We also investigated what will be the next most important bottleneck in SPAX and how to remove it. We found that the newly developed system network called Xcent-Net will not be a bottleneck in the I/O data path. We also show the optimal configuration that is to be considered for system tuning.

• The Transactions of the Korea Information Processing Society
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• v.7 no.9
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• pp.2827-2835
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• 2000

In recent years, much attention has been focused on improving I/O devices' processing speed which is essential in such large data processing areas as multimedia data processing. And studies on high-performance parallel file systems are considered to be one of such efforts. In this paper, an efficient disk allocation scheme is proposed for high-performance parallel file systems. In other words, the concept of a parallel disk file's parallelism is defined using data declustering characteristic of a given parallel file. With the concept, an efficient disk allocation scheme is proposed which calculates the appropriate degree of data declustering on disks for each parallel file in order to obtain the maximum throughput when more than one parallel file is used at the same time. Since, calculation for obtaining the maximum throughput is too complex as the number of parallel files increases, an approximate disk allocation algorithm is also proposed in this paper. The approximate algorithm is very simple and especially provides very good results when I/O workload is high. In addition, it has shown that the approximate algorithm provides the optimal disk allocation for the maximum throughput when the arrival rate of I/O requests is infinite.