• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.3
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• pp.1362-1376
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• 2016

A cloud computing system can be characterized by the provision of resources in the form of services to third parties on a leased, usage-based basis, as well as the private infrastructures maintained and utilized by individual organizations. To attain the desired reliability and energy efficiency in a cloud data center, trade-offs need to be carried out between system performance and power consumption. Resolving these conflicting goals is often the major challenge encountered in the design of optimization strategies for cloud data centers. The work presented in this paper is directed towards the development of an Energy-efficient and Performance-aware Cloud System equipped with strategies for dynamic switching of optimization approach. Moreover, a platform is also provided for the deployment of a Wind Farm CMS (Condition Monitoring System) which allows ubiquitous access. Due to the geographically-dispersed nature of wind farms, the CMS can take advantage of the cloud's highly scalable architecture in order to keep a reliable and efficient operation capable of handling multiple simultaneous users and huge amount of monitoring data. Using the proposed cloud architecture, a Wind Farm CMS is deployed in a virtual platform to monitor and evaluate the aging conditions of the turbine's major components in concurrent, yet isolated working environments.

• The Journal of Korean Institute of Next Generation Computing
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• v.13 no.5
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• pp.80-92
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• 2017

The popularity of cloud computing has led to the emergence of various types of cloud services, and the hybrid cloud, a deployment model that integrates public cloud and private cloud and offset their shortcomings, is in the spotlight recently. However, the complexity of different clouds integration and the lack of related integration solutions have delayed the adoption of hybrid cloud and cloud strategy by companies and organizations. Therefore, in this paper, we propose a cloud integration mechanism to solve the integration complexity problem. The cloud integration mechanism proposed in this paper consists of integration script that solves the cloud integration by the script based on the hybrid cloud function, a process of creating and executing it, and a script creation model applying the software design pattern. By integrating the various cloud services, we can quickly generate scripts that meet the user's needs. It is expected that the introduction of hybrid cloud and the acquisition of cloud strategy can be accelerated through this proposed integration mechanism.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.3
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• pp.1523-1545
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• 2019

Cloud computing is now a widespread and economical option when data owners need to outsource or share their data. Designing secure and efficient data access control mechanism is one of the most challenging issues in cloud storage service. Anonymous broadcast encryption is a promising solution for its advantages in the respects of computation cost and communication overload. We bring forward an efficient anonymous identity-based broadcast encryption construction combined its application to the data access control mechanism in cloud storage service. The lengths for public parameters, user private key and ciphertext in the proposed scheme are all constant. Compared with the existing schemes, in terms of encrypting and decrypting computation cost, the construction of our scheme is more efficient. Furthermore, the proposed scheme is proved to achieve adaptive security against chosen-ciphertext attack adversaries in the standard model. Therefore, the proposed scheme is feasible for the system of data access control in cloud storage service.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.3
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• pp.482-488
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• 2012

Desktop is offered to each individual in Educational environments of school or academy, as the users are increasing, the more Desktop is required for each person. Huge Desktop accession resulted in many problems including difficulty of management, Software and Hardware cost rising, cramped places, power consumption increasing and etc. To solve those problems, we focus into uprising technology solution, such as Multi Computer, Desktop Virtualization, and DaaS(Desktop as a Service). In this paper, existing problems that can dramatically improve the private cloud computing for desktop virtualization with the requirements of the system were analyzed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.9
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• pp.4165-4187
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• 2016

As an emerging technology, cloud computing is a revolution in information technology that attracts significant attention from both public and private sectors. In this paper, we proposed a dynamic approach for live migration to obviate overloaded machines. This approach is applied on OpenStack, which rapidly grows in an open source cloud computing platform. We conducted a cost-aware dynamic live migration for virtual machines (VMs) at an appropriate time to obviate the violation of service level agreement (SLA) before it happens. We conducted a preemptive migration to offload physical machine (PM) before the overload situation depending on the predictive method. We have carried out a distributed model, a predictive method, and a dynamic threshold policy, which are efficient for the scalable environment as cloud computing. Experimental results have indicated that our model succeeded in avoiding the overload at a suitable time. The simulation results from our solution remarked the very efficient reduction of VM migrations and SLA violation, which could help cloud providers to deliver a good quality of service (QoS).

• Journal of Convergence for Information Technology
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• v.9 no.9
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• pp.33-37
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• 2019

According to the enforcement of the Cloud Computing Development and User Protection Act, a new paradigm called as Cloud Computing is coming to the fore among public and private domestic enterprises. Therefore, domestic companies should develop SaaS products specialized for the domestic market and try to preempt the IaaS market ahead of global companies. Now we are facing a necessity to combine all the cloud systems in Korean government to operate seamlessly in a harmony. In this paper, we will look at the prospect of future development of related industry through cloud computing concept and G-cloud's cloud management system (G-CMS). G-CMS can be seen as the first system to comprehensively manage heterogeneous Unix virtualization systems. G-CMS can also save costs by managing heterogeneous virtualization systems in data centers.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.8
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• pp.3455-3473
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• 2016

Cloud computing is a paradigm in which information is permanently stored in servers on the Internet and cached temporarily on clients. Virtual private network (VPN) is the most widely used technology for secure cloud access. Unfortunately, VPN-based cloud services become unavailable when a VPN failure occurs. In this paper, we propose a new scheme to improve the availability of VPN connections against such failures, called high-availability virtual communication (HAVC). Unlike most of the multipath transmission schemes in the literature, the proposed scheme is implemented by using a virtualization technique, and its protocol functions are independent of existing networks - potential clients are not required to modify their applications or operating systems. Simulation results show that the HAVC can not only tolerate VPN failures but also achieve high transmission performance.

• Journal of Internet Computing and Services
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• v.16 no.1
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• pp.91-100
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• 2015

Recently many companies began to feel the pressures of cost savings due to the global recession, so they have been interested in the Cloud Computing. Cloud Computing is one of using method of IT resources through the network. Users can borrow softwares or hardwares instead of buying them. Many people expect remarkable growth in Cloud Computing industry because of it's effectiveness. But Cloud Computing industry is still at an early stage. Especially, people who in the public sector hesitate to adopt Cloud Computing Services due to security issues and their conservative views. Also, they just have limited understanding, so we need to investigate what they really know and understand. Researches about the Cloud Computing generally focus on technical issues, so we can hardly find researches reference for decision making in considering the services. The study aims to investigate diverse factors for agencies' adoption decisions, such as benefits, costs, and risk in developing the most ideal type of cloud computing service for them, and performs priority analyses by applying ANP (Analytic Network Process). The results identify that features pertaining to the risk properties were considered the most significant factors. According to this research, the usage of private cloud computing services may prove to be appropriate for public environment in Korea. The study will hopefully provide the guideline to many governmental agencies and service providers, and assist the related authorities with cloud computing policy in coming up with the relevant regulations.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.5
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• pp.282-296
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• 2013

With the emergence of cloud computing, more and more sensitive user data are outsourced to remote storage servers. The privacy of users' access pattern to the data should be protected to prevent un-trusted storage servers from inferring users' private information or launching stealthy attacks. Meanwhile, the privacy protection schemes should be efficient as cloud users often use thin client devices to access the data. In this paper, we propose a lightweight scheme to protect the privacy of data access pattern. Comparing with existing state-of-the-art solutions, our scheme incurs less communication and computational overhead, requires significantly less storage space at the user side, while consuming similar storage space at the server. Rigorous proofs and extensive evaluations have been conducted to show that the proposed scheme can hide the data access pattern effectively in the long run after a reasonable number of accesses have been made.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.304-307
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• 2015

Virtualization lacks capabilities for enabling the application to scale efficiently because of new applications components which are raised to be configured on demand. In this paper, we propose an architecture that affords mobile app based on nomadic smartphone using not only mobile cloud computing-cloudlet architecture but also a dedicated platform that relies on using virtual private mobile networks to provide reliable connectivity through Long Term Evolution (LTE) wireless communication. The design architecture lies with how the cloudlet host discovers service and sends out the cloudlet IP and port while locating the user mobile device. We demonstrate the effectiveness of the proposed architecture by implementing an android application responsible of real time analysis by using a vehicle to applications smart phones interface approach that considers the smartphones to act as a remote users which passes driver inputs and delivers outputs from external applications.