• Annual Conference of KIPS
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• 2010.11a
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• pp.264-267
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• 2010

현대의 시스템들은 매우 복잡해지고 있으며 그 규모 또한 점점 커지고 있다. 또한 기술의 발달로 서로 상호작용하는 시스템들이 많아졌으며, 비즈니스적 요구 사항의 증가로 인해 통합되는 시스템들도 많아지고 있다. 시스템의 유지 보수는 비용과 노력 등 시간이 갈수록 고객과 개발자에게 더 많은 부담이 되고 있다. 때문에 자율 컴퓨팅 시스템이 제안되었다. 자율 컴퓨팅 시스템은 시스템 스스로가 자신을 관리하는 자가 적응하는 시스템이다. 이러한 자율 컴퓨팅이 이루어 지기 위해서는 데이터베이스화 된 시스템의 결함 정보, 각 결함에 따른 하나 이상의 전략이 존재하여 적절한 선택을 할 수 있도록 하여야 한다. 본 논문은 OCL 을 기반으로 하여 설계 단계의 시스템 모델에서 예상 가능한 결함 정보를 추출하여 결함 리스트를 생성하는 연구를 내용으로 한다. 이를 통하여 개발자는 효율적으로 자가 적응 시스템을 구축할 수 있다. 그리고 연구의 효율성을 검증하기 위해 ATM 시스템을 대상으로 평가를 한다.

• The KIPS Transactions:PartA
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• v.13A no.6 s.103
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• pp.495-500
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• 2006

The role of autonomic and intelligent agents in various environments is getting more important as demand on ubiquitous computing grows. The agents exchange information using the ACL (Agent Communication Language) to autonomously solve the problems. In this paper we propose a way of efficient interoperability technique between the agent framework built based on the international standard FIPA(Foundation for Intelligent Physical Agents) and the CORBA event service-based information bus adapter developed by us. The design and implementation of EMTI (Efficient Message Transport Interface) allowing communication between the information bus adapter which is non-agent platform and JADE platform are presented and its performance is evaluated by letting them exchange a large amount of messages.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.8
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• pp.507-516
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• 2013

Mobile devices have limited computing power and resources. Since mobile devices are equipped with rich network connectivity, an approach to subscribe cloud services can effectively remedy the problem, which is called Mobile Cloud Computing (MCC). Most works on MCC depend on a method to offload functional components at runtime. However, these works only consider the limited verion of offloading to a pre-defined, designated node. Moveover, there is the limitation of managing services subscribed by applications. To provide a comprehensive and practical solution for MCC, in this paper, we propose a self-stabilizing process and its management-related methods. The proposed process is based on an autonomic computing paradigm and works with diverse quality remedy actions such as migration or replicating services. And, we devise a pratical offloading mechanism which is still in an initial stage of the study. The proposed offloading mechanism is based on our proposed MCC meta-model. By adopting the self-stabilization process for MCC, many of the technical issues are effectively resolved, and mobile cloud environments can maintain consistent levels of quality in autonomous manner.

• The KIPS Transactions:PartA
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• v.12A no.5 s.95
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• pp.395-404
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• 2005

There have been large concerns about survivability defined as the capability of a system to perform a mission-critical role, in a timely manner, in the presence of attacks, failures. In particular, One of the most important core technologies required for the design of the ITS(Intrusion Tolerance System) that performs continuously minimal essential services even when the computer system is partially compromised because of intrusions is the survivability one of In included the dependability analysis of a reliability and availability etc. quantitative dependability analysis of the In. In this Paper, we applied self-healing mechanism utilizing two factors of self-healing mechanism (fault model and system response), the core technology of autonomic computing to secure the protection power of the ITS and consisted of a state transition diagram of the ITS composed of a primary server and a backup server. We also defined the survivability, availability, and downtime cost of the ITS, and then performed studies on simulation experiments and two cases of vulnerability attack. Simulation results show that intrusion tolerance capability at the initial state is more important than coping capability at the attack state in terms of the dependability enhancement.

• Journal of Pharmacopuncture
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• v.19 no.3
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• pp.207-212
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• 2016

Objectives: Acupuncture treatments are safe and effective for a wide variety of diseases involving autonomic dysregulation. Heart rate variability (HRV) is a noninvasive method for assessing sympathovagal balance. The low frequency/high frequency (LF/HF) spectral power ratio is an index of sympathovagal influence on heart rate and of cardiovascular health. This study tests the hypothesis that from rest to 30% to 50% of peak oxygen consumption, the nonlinear Conte-Zbilut-Federici (CZF) method of computing the LF/HF ratio is a more reliable index of changes in the HRV than linear methods are. Methods: The subjects of this study were 10 healthy young adults. Electrocardiogram RR intervals were measured during 6-minute periods of rest and aerobic exercise on a cycle ergometer at 30% and 50% of peak oxygen consumption ($VO_{2peak}$). Results: The frequency domain CZF computations of the LF/HF ratio and the time domain computations of the standard deviation of normal-to-normal intervals (SDNN) decreased sequentially from rest to 30% $VO_{2peak}$ (P < 0.001) to 50% $VO_{2peak}$ (P < 0.05). The SDNN and the CZF computations of the LF/HF ratio were positively correlated (Pearson's r = 0.75, P < 0.001). fast Fourier transform (FFT), autoregressive (AR) and Lomb periodogram computations of the LF/HF ratio increased only from rest to 50% $VO_{2peak}$. Conclusion: Computations of the LF/HF ratio by using the nonlinear CZF method appear to be more sensitive to changes in physical activity than computations of the LF/HF ratio by using linear methods. Future studies should determine whether the CZF computation of the LF/HF ratio improves evaluations of pharmacopuncture and other treatment modalities.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.1
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• pp.86-90
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• 2008

Ubiquitous Smart pace connects many kinds of smart object to satisfy user's demands. Thus, not only excessive loads but also resource collisions occur among service objects while configurating services to fulfill the user's request. After all, as malfunction occurs between service objects, it offers wrong service to user or does not respond to service request. To solve these problems, Ubiquitous Smart Space is observed by monitoring system of function, performance, and status of objects. Therefore, optimized function, performance and duality of service of smart space service for user should be improved by recording log and analyzing recorded the log. In this paper, we suggest a novel monitoring system to optimize performance according to pattern of diverse services and execute self-recovery on system down and malfunction.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.5
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• pp.260-270
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• 2007

Owing to the improved wireless communication technologies, it is possible to provide streaming service of multimedia with PDAs and mobile phones in addition to desktop PCs. Since mobile client devices have low computing power and low network bandwidth due to wireless network, the transcoding technology to adapt media for mobile client devices considering their characteristics is necessary. However, since mobile clients use wireless network and the wireless network have less stable bandwidth according to distance from AP and environments, it is hard to support stable QoS to mobile clients. In this paper, we propose a dynamic bit rate control method for transcoding in order to supprot stable QoS of streaming media service to mobile clients via wireless network. The proposed method is shown to serve seamless streaming media service with adaptive bit rate control according to state of wireless network in real time and to reduce transmission failure from experiment.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.8
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• pp.1368-1387
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• 2011

In recent years, ubiquitous and pervasive scenarios have emerged as a complex ecosystem where differentiated software/hardware components interoperate wirelessly and seamlessly. The goal is to enable users to continuously access services and contents, and to always get the best out of their current environment and available resources. In such dynamic and flexible scenarios, the need emerges for flexible and general solutions for continuous runtime self-reconfiguration and self-optimization of ubiquitous support software systems. This paper proposes a fully reconfigurable middleware approach that aims at reconfiguring complex software systems made up of heterogeneous off-the-shelf components from both functional and non-functional perspectives. Our middleware can also extend already existing and non-reconfigurable middleware/applications in an easy and flexible way, with no need to re-design them. The proposed design principles have been practically applied to the implementation of a runtime self-reconfigurable middleware called Off-The-Shelf Ready To Go (OTS-RTG), implemented on top of iPOJO. The reported experimental results both exhibit a limited overhead and show the wide applicability of the proposed solution to many application scenarios, including complex, industrial, Enterprise Service Bus-based ones.

• Journal of Internet of Things and Convergence
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• v.1 no.1
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• pp.21-25
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• 2015

The Internet of Thing (IoT) will be a very important core technology to implement Intelligent Smart Home Network and it will take charge of an important role connected to Smart Phone, Cloud Computing in the Ubiquitous environment. In this paper, Internal Autonomous Regulation by human autonomic nervous system was studied and its core mechanism was applied to the design of IoT based Autonomous Regulation System for Intelligent Smart Home Network. We proposed an autonomous regulating mechanism in which the factors of Temperature, Humidity and Illumination are automatically adjusted as they communicate with the connected things.

• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.923-930
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• 2004

Wireless sensor networks is a core technology of ubiquitous computing which enables the network to aware the different kind of context by integrating exiting wired/wireless infranet with various sensor devices and connecting collected environmental data with applications. However it needs an energy-efficient approach in network layer to maintain the dynamic ad hoc network and to maximize the network lifetime by using energy constrained node. Cluster-based data aggregation and routing are energy-efficient solution judging from architecture of sensor networks and characteristics of data. In this paper. we propose a new distributed clustering algorithm in using distance from the sink. This algorithm shows that it can balance energy dissipation among nodes while minimizing the overhead. We verify that our clustering is more en-ergy-efficient and thus prolongs the network lifetime in comparing our proposed clustering to existing probabilistic clustering for sensor network via simulation.