• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.364-364
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• 2000

Timed Petri Net(TPN) is one of methods to model and to analyze Discrete Event Dynamic Systems(DEDSs) with real time values. It has two time values, earliest firing time ($\alpha$$_{i}$) and latest firing time ($\beta$$_{I}$) for the each transition. A transition of TPN is fired at arbitrary time of time interval ($\alpha$$_{I}$, $\beta$$_{i}$). Uncertainty of firing time gives difficulty to analyze and estimate a modeled system. In this paper, we proposed the Fuzzy Transition Timed Petri Net(FTTPN) with fuzzy theory to determine the optimal transition time (${\gamma}$$_{i}$). The transition firing time (${\gamma}$$_{i}$) of FTTPN is determined from fuzzy controller which is modeled with information of state transition. Each of the traffic signal controllers are modeled using the proposed method and timed petri net. And its Performance is evaluated by simulation of traffic signal controller. controller.

• Smart Structures and Systems
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• 제29권1호
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• pp.1-16
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• 2022

Despite recent breakthroughs in deep learning and computer vision fields, the pixel-wise identification of tiny objects in high-resolution images with complex disturbances remains challenging. This study proposes a modified U-net for tiny crack segmentation in real-world steel-box-girder bridges. The modified U-net adopts the common U-net framework and a novel Self-Attention-Self-Adaption (SASA) neuron as the fundamental computing element. The Self-Attention module applies softmax and gate operations to obtain the attention vector. It enables the neuron to focus on the most significant receptive fields when processing large-scale feature maps. The Self-Adaption module consists of a multiplayer perceptron subnet and achieves deeper feature extraction inside a single neuron. For data augmentation, a grid-based crack random elastic deformation (CRED) algorithm is designed to enrich the diversities and irregular shapes of distributed cracks. Grid-based uniform control nodes are first set on both input images and binary labels, random offsets are then employed on these control nodes, and bilinear interpolation is performed for the rest pixels. The proposed SASA neuron and CRED algorithm are simultaneously deployed to train the modified U-net. 200 raw images with a high resolution of 4928 × 3264 are collected, 160 for training and the rest 40 for the test. 512 × 512 patches are generated from the original images by a sliding window with an overlap of 256 as inputs. Results show that the average IoU between the recognized and ground-truth cracks reaches 0.409, which is 29.8% higher than the regular U-net. A five-fold cross-validation study is performed to verify that the proposed method is robust to different training and test images. Ablation experiments further demonstrate the effectiveness of the proposed SASA neuron and CRED algorithm. Promotions of the average IoU individually utilizing the SASA and CRED module add up to the final promotion of the full model, indicating that the SASA and CRED modules contribute to the different stages of model and data in the training process.

• 한국항행학회논문지
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• 제21권2호
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• pp.187-192
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• 2017

단일 모드 광섬유 (SMF; single mode fiber)의 길이와 중계 구간 당 잉여 분산 (RDPS; residual dispersion per span)이 랜덤하게 분포하는 광 위상 공액과 결합된 분산 제어 (DM; dispersion management)가 적용된 장거리 (50 fiber spans ${\times}80km$) 전송 링크에서 SMF와 분산 보상 광섬유 (DCF; dispersion compensating fiber) 배열과 전체 잉여 분산 (NRD; net residual dispersion)을 조절하는 위치에 따른 왜곡된 WDM 채널의 보상 특성을 수치적으로 분석해 보았다. NRD 조절 위치는 중계 구간을 구성하는 SMF와 DCF의 배열과 관계되어 있지만, NRD 조절의 구체적 위치보다 중계 구간을 이루는 SMF와 DCF의 배열이 WDM 채널의 수신 성능에 영향을 미치는 것을 확인하였다.

• 한국멀티미디어학회논문지
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• 제10권6호
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• pp.745-753
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• 2007

The wireless medium is known to be time-varying which could affect and result to a poor network's performance. As a solution, an opportunistic scheduling and power control algorithm based on IEEE 802.11 MAC protocol is proposed in this paper. The algorithm opportunistically exploits the channel condition for better network performance. Convex optimization problems were also formulated i.e. the overall transmission power of the system is minimized and the "net-utility" of he system is maximized. We have proven that an optimal transmission power vector may exist, satisfying the maximum power and SINR constraints at all receivers, thereby minimizing overall transmission power and maximizing net-utility of the system.

• Nuclear Engineering and Technology
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• 제44권8호
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• pp.929-938
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• 2012

The Computerized Procedure System (CPS) is one of the primary operating support systems in the digital Main Control Room. The CPS displays procedure on the computer screen in the form of a flow chart, and displays plant operating information along with procedure instructions. It also supports operator decision making by providing a system decision. A procedure flow should be correct and reliable, as an error would lead to operator misjudgment and inadequate control. In this paper we present a modeling for the CPS that enables formal verification based on Petri nets. The proposed State Token Petri Nets (STPN) also support modeling of a procedure flow that has various interruptions by the operator, according to the plant condition. STPN modeling is compared with Coloured Petri net when they are applied to Emergency Operating Computerized Procedure. A converting program for Computerized Procedure (CP) to STPN has been also developed. The formal verification and validation methods of CP with STPN increase the safety of a nuclear power plant and provide digital quality assurance means that are needed when the role and function of the CPS is increasing.

• 한국위성정보통신학회논문지
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• 제12권2호
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• pp.71-78
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• 2017

망 중립성은 ISP가 이용자에게 비차별성, 상호접속성, 접근성을 보장하여 누구든지 통제나 간섭 없이 동등한 서비스를 받을 수 있도록 하는 개념이다. 그러나 현재 인터넷 망은 P2P 서비스 확산과 실시간 대용량 비디오 스트리밍 서비스와 같이 버퍼링에 민감한 서비스에서 트래픽이 급증하고 있다. 이를 관리하기 위해 ISP가 서비스를 간섭, 변경, 통제하는 등 망 중립성을 훼손하면서, 망 중립성에 대한 논쟁이 끊임없이 발생하고 있다. 따라서 본 논문에서는 망 중립성의 원칙과 개념, 이에 대한 국내외의 입법 정책현황을 비교 분석하고, 이를 기반으로 국내 망 중립성 가이드라인의 쟁점사항과 개선방안을 제시한다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2006년도 춘계학술발표대회
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• pp.227-230
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• 2006

인터넷이라는 물리적 네트워크 인프라가 점차 안정화된 후, 인터넷 서비스 사용자의 기하급수적 확대로 인한 서비스되는 콘텐츠의 양의 빅뱅 속에서 관련된 콘텐츠와 서비스의 효율적인 관리의 필요성이 절실히 대두되었다. 이에 IT 전반에 걸쳐 화두로 등장한 이슈가 바로 CMS의 도입이다. 이에 본 논문에서는 CMS의 정의와 그 필요성과 도입효과에 대해서 살펴보고, 다른 일반적인 시스템과 비교하여.Net Framework 환경에서의 CMS 구현의 특징과 장점에 대해서 살펴보고 실제로 한국형 환경에 걸맞게 구현한 K-Contents Pathfinder System에서 커스터마이즈된 Control, Placeholder, Work flow들의 기능에 대해서 요약 설명한다.

• 한국전자거래학회지
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• 제1권1호
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• pp.227-247
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• 1996

Presented in this paper is a control model for developing virtual factory simulator, which is being operated under the distributed environment. The control model consists of production activity plan and information flows. To incorporate elements of the characteristics of the distributed control system, we suggested a collaboration model. This model is working under the client/server architecture, and also designed for cooperative-distributed shop control(CDSC) system in order to exploit several advantages of client/server architecture. Collaboration among each agent(or client) is done through negotiation and task sharing. Based on a contract net model, the CDSC system has three kinds of agents-order agent, resource agent, and communication forwarding agent. Each agent performs shop scheduling and control through negotiation on contract net. No node in CDSC system can have authority over other node. A bidding scheme is employed far negotiation between order agent and resource agents. The CDSC system can support re-negotiation among resource agents and an algorithm for re-negotiation is also developed. Experimental results are shown to advocate the effectiveness of the CDSC system for CIM environments.

• 인터넷정보학회논문지
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• 제3권4호
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• pp.19-26
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• 2002

본 논문에서는 워크플로우 관리 시스템의 빌드타임 기능에 속하는 모델링 시스템을 다중 에이전트 기반으로 구현하였다. 본 논문에서 제안된 다중 에이전트 기반 워크플로우 모델링 시스템은 클라이언트의 경량을 위하여 자바를 이용하였으며, 프로세스 정의에 필요한 세션, 조직, 관련데이터, 응용프로그램 속성들을 별도의 에이전트로 구성하였다 또한, 프로세스 정의를 위한 모델은 ICN(Information Control Net)을 이용하여 작성된 모델의 문법(syntax)를 검증하였으며, 타 워크플로우 엔진과의 연동을 위하여 WfMC에서 정의된 인터페이스 형태인 WPDL로 import/export할 수 있는 기능을 제공한다.

• 한국IT서비스학회지
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• 제14권4호
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• pp.221-236
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• 2015

Application software is delivered to customers as a form of service at cloud environment. A cloud service provider is a marketplace between supply side (application providers) and demand side (customers). Cloud service providers have to validate applications to be included in their service portfolio. Not only performance, security, networking, compliances should be checked but also business contract, authentication should be provided. Organization customers are more sensitive to these validation criteria and process. We study the Internet2 NET+, which is a successful cloud marketplace of applications for research and education organizations. This case study shows us three things : (i) a cloud marketplace's application management process : selection, validation, transition to service, customization of applications (ii) what a cloud marketplace has for its infrastructure like authentication, security, access control etc. (iii) what a cloud marketplace has as its governance structure. This case study will provide informative analysis of Internet2 NET, a profit-making vertical and buyer's marketplace (education industry). And we will get some strategic implications for planning and implementing cloud marketplaces.