• Journal of Korea Multimedia Society
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• v.25 no.2
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• pp.197-205
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• 2022

The Cyber Physical System(CPS) is an important concept in achieving SMSs(Smart Manufacturing Systems). Generally, CPS consists of physical and virtual elements. The former involves manufacturing devices in the field space, whereas the latter includes the technologies such as network, data collection and analysis, security, and monitoring and control technologies in the cyber space. Currently, all these elements are being integrated for achieving SMSs in which we can control and analyze various kinds of producing and diagnostic issues in the cyber space without the need for human intervention. In this study, we focus on implementing a production equipment monitoring system related to building a SMS. First, we describe the development of a fog-based gateway system that links physical manufacturing devices with virtual elements. This system also interacts with the cloud server in a multimedia network environment. Second, we explain the proposed network infrastructure to implement a monitoring system operating on a cloud server. Then, we discuss our monitoring applications, and explain the experience of how to apply the ML(Machine Learning) method for predictive diagnostics.

• IEMEK Journal of Embedded Systems and Applications
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• v.7 no.5
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• pp.267-275
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• 2012

In this paper, we present the model-based autonomic computing framework for a cyber-physical system which provides a self-management and a self-adaptation characteristics. A development process using this framework consists of two phases: a design phase in which a developer models faults, normal status constrains, and goals of the CPS, and an operational phase in which an autonomic computing engine operates monitor-analysis-plan-execute(MAPE) cycle for managed resources of the CPS. We design a hierachical architecture for autonomic computing engines and adopt the Model Reference Adaptive Control(MRAC) as a basic feedback loop model to separate goals and resource management. According to the GroundVehicle example, we demonstrate the effectiveness of the framework.

• IEMEK Journal of Embedded Systems and Applications
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• v.7 no.6
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• pp.311-321
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• 2012

When developing a CPS, since it is nature of CPS to interact with a physical system, CPS should be verified during its development process by real-time simulation supporting timely interactions between the simulator and existing implemented hardwares. Furthermore, when a part of a simulated system is implemented to real hardwares, i.e., incremental development, the simulator should aware changes of the simulated system and apply it automatically without manual description of the changes for effective development. For this, we suggest a real-time simulation framework including the concept of 'port' which abstracts communication details between the tasks, and a scheduling algorithm for guaranteeing 'real-time correctness' of the simulator.

• Economic and Environmental Geology
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• v.50 no.5
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• pp.363-373
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• 2017

In the present study, adaptability of cyber-physical system (CPS) for risk management of $CO_2$ storage site is examined and the subagging regression (SBR) method is proposed as a key component of the cyber-twin to estimate the risk due to potential $CO_2$ leakage. For these purposes, $CO_2$ concentration data monitored from a controlled $CO_2$ release field experiment is employed to validate the potentialities of the SBR method. From the validation study, it is found that the SBR method has robust estimation capability by showing minimal influence from anomalous measurements, and makes stable and sound predictions for the forthcoming $CO_2$ concentration trend. In addition, the method is found to be well suited as a tool of operational risk assessment based on real-time monitoring data due to the computational efficiency. The overall results suggest that the SBR method has potential to be an important component comprising the cyber twin of CPS for risk management of $CO_2$ storage site.

• IEMEK Journal of Embedded Systems and Applications
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• v.7 no.5
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• pp.241-246
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• 2012

As the convergence between the conventional physical systems and IT computing resource is increased, the new paradigm of embedded system called Cyber Physical System (CPS) emerged. CPSs have many sensors, actuators and computing devices to understand and to control the physical system. As these all components are tightly coupled each other, standardized middleware such as Data Distribution Service (DDS) is considered to be deployed. But DDS takes too long time to discover each other in the large-scal CPS environment and has not precise specification of its execution architecture to provide efficient data exchange. In this paper, we design the efficient DDS architecture for development with interoperability to provide the high reliable data distribution. in real-time and propose the communication entity discovery procedure.

• KIPS Transactions on Software and Data Engineering
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• v.10 no.8
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• pp.287-300
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• 2021

Collaborative Cyber-Physical Systems (CCPS) are those systems that contain tightly coupled physical and cyber components, massively interconnected subsystems, and collaborate to achieve a common goal. The safety of a single Cyber-Physical System (CPS) can be achieved by following the safety standards such as ISO 26262 and IEC 61508 or by applying hazard analysis techniques. However, due to the complex, highly interconnected, heterogeneous, and collaborative nature of CCPS, a fault in one CPS's components can trigger many other faults in other collaborating CPSs. Therefore, a safety assurance technique based on fault criticality analysis would require to ensure safety in CCPS. This paper presents a Fault Criticality Matrix (FCM) implemented in our tool called CPSTracer, which contains several data such as identified fault, fault criticality, safety guard, etc. The proposed FCM is based on composite hazard analysis and content-based relationships among the hazard analysis artifacts, and ensures that the safety guard controls the identified faults at design time; thus, we can effectively manage and control the fault at the design phase to ensure the safe development of CPSs. To justify our approach, we introduce a case study on the Platooning system (a collaborative CPS). We perform the criticality analysis of the Platooning system using FCM in our developed tool. After the detailed fault criticality analysis, we investigate the results to check the appropriateness and effectiveness with two research questions. Also, by performing simulation for the Platooning, we showed that the rate of collision of the Platooning system without using FCM was quite high as compared to the rate of collisions of the system after analyzing the fault criticality using FCM.

• Journal of KIISE
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• v.45 no.1
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• pp.36-44
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• 2018

Due to the advent of the 4th Industrial Revolution, it is imperative that we aggressively continue to develop state-of-the-art, cutting edge ICT technology relative to autonomous vehicles, intelligent robots, and so forth. Especially, systems based on convergence IT are being developed in the form of CPSs (Cyber Physical Systems) that interwork with sensors and actuators. Since conventional CPS specification only expresses behavior of one system, specification for collaboration and diversity of CPS systems with characteristics of hyper-connectivity and hyper-convergence in the 4th Industrial Revolution has been insufficiently presented. Additionally, behavioral modeling of CPSs that considers more collaborative characteristics has been unachieved in real-time application domains. This study defines the non-functional requirements that should be identified in developing embedded software for real-time constrained collaborating CPSs. These requirements are derived from ISO 25010 standard and formally specified based on state-based timed process. Defined non-functional requirements may be reused to develop the requirements for new embedded software for CPS, that may lead to quality improvement of CPS.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.225-228
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• 2016

CPS(Cyber Physical System)는 사이버 세계(cyber world)와 물리적 세계(physical word)를 연결하여, 현실과 사이버의 정보를 융합 분석하고, 분석한 데이터를 현실에 Feedback 하는 자동적이고 지능적인 제어 시스템이다. 이러한 CPS는 빅데이터를 분석하여 사용자에게 알맞은 정보를 제공해 주며 딥러닝(Deep Learning)을 통해 정확하고 세밀한 Feedback을 제공하는 등 이종 복합 시스템 간의 고신뢰성과 실시간성을 보장하는 무결점 자율 제어 시스템으로 주목 받고 있다. 실생활에서는 의료, 헬스케어, 교통, 에너지, 홈, 국방, 재난대응, 농업, 제조 등에서 폭 넓게 사용되고 있다. 해외에서는 이와 같은 CPS를 이용해 한 분야에 세밀하게 접목시켜 발전을 도모하며, CPS에 의해 변혁되는 데이터 구동형 사회를 준비하고 있다. 하지만, 이러한 CPS를 사용할 때, 보안의 문제점으로 대규모 정전사태가 발생하고, 생명을 위협하는 등의 취약점 또한 드러나고 있어 이에 대한 보안의 중요성과 CPS의 적용분야를 파악하여 전반적인 보안 문제점을 분석하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.05a
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• pp.305-307
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• 2023

현재 제조업에서 설비 라인 증축 및 최적화를 위해서는 공정 분석과 설비 시스템 테스트가 요구되며, 많은 시간과 비용이 소요된다. 이러한 문제를 해결하기 위해, 가상의 설비모델을 이용해 설비검증과 라인 테스트를 수행할 수 있는 다양한 CPS(Cyber Physical System)가 연구되고 있다. 본 논문에서는 다양한 설비 이해관계자 사이의 상호운용성을 확보하기 위해 독일의 Industry 4.0에서 제안한 표준 설비 명세인 AAS(Asset Administration Shell)를 활용한 CPS 구현을 제안한다. SMT(Surface Mounting Technology) 라인 중 Screen Printer를 대상으로, 총 3개의 서브 모델(Sub model)과 17개의 속성(Property)을 AAS 명세하고 이를 이용한 CPS를 구현하는 사례연구를 수행했다. 제안 방법은 표준명세를 활용한 제조 분야 CPS 구현에 적용될 수 있다.

• Convergence Security Journal
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• v.19 no.2
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• pp.59-72
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• 2019

In this day and age physical and cyber boundaries have converged due to the development of new technologies, such as the Internet of Things (IoT) and the Cyber Physical System (CPS). As the relationship between physical system and cyber technology strengthens, more diverse and complex forms of risk emerge. As a result, it is becoming difficult for single organization or government to fully handle this situation alone and cooperation based on information sharing and the strengthening of active defense systems are needed. Shifting to a system in which information suitable for various entities can be shared and automatically responded to is also necessary. Therefore, this study tries to find improvements for the current system of threat information collecting and sharing that can actively and practically maintain cyber defense posture, focusing particularly on the structuring of information sharing platforms. To achieve our objective, we use a risk communication theory from the safety field and propose a new platform by combining an action-oriented security process model.