• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권1호
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• pp.38-57
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• 2016

Service discovery is one of the major challenges in cloud computing environment with a large number of service providers and heterogeneous services. Non-uniform naming conventions, varied types and features of services make cloud service discovery a grueling problem. With the proliferation of cloud services, it has been laborious to find services, especially from Internet-based service repositories. To address this issue, services are crawled and clustered according to their similarity. The clustered services are maintained as a catalogue in which the data published on the cloud provider's website are stored in a standard format. As there is no standard specification and a description language for cloud services, new efficient and intelligent mechanisms to discover cloud services are strongly required and desired. This paper also proposes a key-value representation to describe cloud services in a formal way and to facilitate matching between offered services and demand. Since naïve users prefer to have a query in natural language, semantic approaches are used to close the gap between the ambiguous user requirements and the service specifications. Experimental evaluation measured in terms of precision and recall of retrieved services shows that the proposed approach outperforms existing methods.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권3호
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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.

• 한국대기환경학회지
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• 제22권2호
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• pp.235-247
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• 2006

Aerosol indirect radiative forcing of climate change is considered the most uncertain forcing of climate change over the industrial period, despite numerous studies demonstrating such modification of cloud properties and several studies quantifying resulting changes in shortwave radiative fluxes. Detection of this effect is made difficult by the large inherent variability in cloud liquid water path (LWP): the dominant controlling influence of LWP on optical depth and albedo masks any aerosol influences. Here we have used ground-based remote sensing of cloud optical depth (${\tau}_c$) by narrowband radiometry and LWP by microwave radiometry to determine the dependence of optical depth on LWP, thereby permitting examination of aerosol influence. The method is limited to complete overcast conditions with liquid-phase single layer clouds, as determined mainly by millimeter wave cloud radar. The results demonstrate substantial (factor of 2) day-to-day variation in cloud drop effective radius at the ARM Southern Great Plains site that is weakly associated with variation in aerosol loading as characterized by light-scattering coefficient at the surface. The substantial scatter suggests the importance of meteorological influences on cloud drop size as well, which should be analyzed in the further intensive studies. Meanwhile, it is notable that the decrease in cloud drop effective radius results in marked increase in cloud albedo.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권9호
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• pp.4197-4219
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• 2017

Cloud computing is a new service to provide dynamic, scalable virtual resource services via the Internet. Cloud market is available to multiple cloud computing resource providers and users communicate with each other and participate in market transactions. However, since cloud computing is facing with more and more security issues, how to complete the allocation process effectively and securely become a problem urgently to be solved. In this paper, we firstly analyze the cloud resource allocation problem and propose a mathematic model based on combinatorial double auction. Secondly, we introduce a trust evaluation mechanism into our model and combine genetic algorithm with simulated annealing algorithm to increase the efficiency and security of cloud service. Finally, by doing the overall simulation, we prove that our model is highly effective in the allocation of cloud resources.

• International Journal of Internet, Broadcasting and Communication
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• 제7권1호
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• pp.42-48
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• 2015

Generally, the current commercial cloud system is hosted by the centralization large datacenter. However, the other clouding forms existed and one of them is the P2P cloud. The P2P Cloud is a distributed systems, is freedom to join and leave and is possible to provide the IaaS. Commonly, P2P Cloud System is based on Pure-P2P System. Since a number of connection paths exist, it has a high reliability and easily scalability of the network. However, there are disadvantages of the slow rate of route because of looking up the all peers in order to search for the peer. In this paper, it proposes the P2P cloud system based on super-peer P2P. Super-peer P2P system has fast routing time, because of searching for cluster unit and it also can has high reliability and high scalability. We designs the super Peer cloud service and proposes the system model and Resource Allocation Algorithm for IaaS in Super peer P2P environment.

• 한국IT서비스학회지
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• 제11권1호
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• pp.173-196
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• 2012

Cloud computing is provided on demand service via the internet, allowing users to pay for the service they actually use. Since cloud computing is emerging stage in industry, many companies and government consider adopting the cloud computing. Actually a variety of factors may influence on the adopting decision making of cloud computing. The objective of this study is to explore the significant factors affecting the adoption decision of enterprise cloud computing. A research model has been suggested based on TOE framework and outsourcing decision framework. Based on 302 data collected from managers in various industries, the major findings are following. First, the benefit factors of cloud computing service such as agility and cost reduction have direct and positive effects on adoption of the service. Second, lock-in as a risk factor of cloud computing service has a negative effect while security has not. Third, both internal and external environment factors have positive effects on adoption of the service.

• 전자통신동향분석
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• 제35권3호
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• pp.45-54
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• 2020

The cloud computing industry has focused on establishing a cloud-based business environment for enterprises with efforts to convert using their own on-premise computing infrastructures to using cloud services. With these efforts, using cloud services has become natural, especially for the IT industry. The cloud computing industry is moving toward proliferation of the cloud computing environment into various evolving industries. Along with industrial trends, new technical trends such as edge computing and multi-cloud are emerging. These trends are expected to create new business models and develop related service ecosystems, providing new opportunities for service providers and new experiences for users. A mong those emerging technologies, multi-cloud technology is expected to realize unlimited global cloud computing resources by unifying cloud resources from multiple public cloud service providers. In this paper, we introduce the concept and related trends of multi-cloud technology. Subsequently, we analyze the main functionalities and several use cases of multi-cloud technology. Finally, we summarize the effects and usefulness of multi-cloud technology in the domestic cloud industry.

• 한국IT서비스학회지
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• 제23권1호
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• pp.27-35
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• 2024

In accordance with the cloud conversion of public sector information systems and the implementation of cloud native introduction policies, review items were presented to review the cloud native of information systems for stable and efficient cloud native deployment. By presenting cloud native considerations when promoting a project, we propose a plan to flexibly respond to policy and business changes and improve development quality and productivity to operate cloud services stably. In order for information project managers to switch to a cloud-native-based information system in order to efficiently utilize the cloud as a cloud, they must decide whether to introduce cloud-native through suitability review questions and sufficiently review development and operation costs and efficiency to promote the project. As a result of conducting a focus group interview (FGI) with a council of cloud native experts, there was an opinion that information systems can be operated in a cloud-native manner even with a monolithic structure. By fully considering the circumstances of each system, development quality and productivity, we expect to be able to operate improved to provide a stable cloud service.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권6호
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• pp.2463-2482
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• 2016

Cloud services are often provisioned to their customers using user-friendly web browsers with flexible and rich plug-in environments. Delay is one of the fundamental performance metrics of these web-based services. Commonly-used network measurement tools usually only measure network delay and it may be difficult to infer the web-delay performance using only network layer measurement approaches. In this paper, we propose to evaluate the application layer delay in a browser-based network measurement platform using engineered scripts. We conducted a delay measurement study using instrumented scripts in the proposed browser-based measurement platform. Our investigation included a comparison study of three browser-scripting delay measurement methods, including Java applet, JSP and Flash ActionScript. We developed a browser-based delay measurement testbed over the Internet so that different delay measurement tools could be evaluated in the same real network environment including typical Internet paths and the Baidu cloud. We also decomposed the components of the end-to-end delay process of the above measurements to reveal the difference and relationship between the network-layer delay and the application-layer delay. Our measurement results characterize the stochastic properties of the application-layer delay over real Internet paths, and how these properties vary from the underlying network layer delay. This browser-scripting measurement approach can be easily deployed on different cloud service platforms to inspect their application-layer delay performance between end clients and the cloud platforms. Our measurement results may provide insights into designing new cloud services with enhanced quality-of-experience perceived by cloud users.

• 인터넷정보학회논문지
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• 제15권1호
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• pp.113-123
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• 2014

세계적인 경기불황의 여파로 수많은 기업들은 IT 인프라에 대한 초기 구축비용 및 유지보수비용 부담을 상당부분 경감시킴으로써 비용을 절감하기 위해 클라우드 컴퓨팅 도입을 서두르고 있다. 비교적 보수적인 준정부기관의 경우도 지난 수년간의 선진화 사업으로 인해 유연해진 조직 및 경영구조로 전화하고 있고, 지방이전에 따른 스마트 워크의 필요성으로 인해 클라우드 기반의 스마트워크 서비스에 대한 논의 및 준비가 한창이다. 본 연구는 준 정부 기관에서 조직원들의 클라우드 기반 스마트워크에 대한 선호도, 특징, 성향, 중점사항 등을 조사하여 이를 유형화하여 향후 준 정부 기관의 클라우드 스마트워크 서비스 발전방안을 제시하였다. 준정부기관의 클라우드 기반 스마트워크 서비스는 편리 추구형, 집중력 추구형, 협업 추구형 등 세 가지로 유형화 되었다.