• Current Optics and Photonics
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• v.4 no.3
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• pp.174-185
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• 2020

Multiscattering occurs when a laser transmits into dense atmosphere targets (e.g. fogs, smoke or clouds), which can cause depolarization effects even though the scattering particles are spherical. In addition, multiscattering effects have additional information about microphysical properties of scatterers. Thus, multiscattering can be utilized to study the microphysical properties of the liquid water cloud. In this paper, a Monte Carlo method was used to simulate multi-scattering transmission properties of Lidar signals in the cloud. The results showed the slope of the degree of linear polarization (SLDLP) can be used to invert the extinction coefficient, and then the cloud effective size (CES) and the liquid water content (LWC) may be easily obtained by using the extinction coefficient and saturation of the degree of linear polarization (SADLP). Based on calculation results, a microphysical properties inversion method for a liquid cloud was presented. An innovative multiscattering polarization Lidar (MSPL) system was constructed to measure the LWC and CES of the liquid cloud, and a new method based on the polarization splitting ratio of the Polarization Beam Splitter (PBS) was developed to calibrate the polarization channels of MSPL. By analyzing the typical observation data of MSPL observation in the northern suburbs of Nanjing, China, the LWC and CES of the liquid water cloud were obtained. Comparisons between the results from the MSPL, MODIS and the Microwave radar data showed that, the microphysical properties of liquid cloud could be retrieved by combining our MSPL and the inversion method.

• Journal of Platform Technology
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• v.9 no.2
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• pp.10-25
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• 2021

Although many studies have been conducted on risk analysis and evaluation in the on-premises environment in information security, studies on effective methodologies of risk analysis and evaluation for cloud computing systems are lacking. In 2015, the Cloud Computing Development Act was enacted, which served as an opportunity to promote the introduction of cloud computing. However, due to the increase in security incidents in the cloud computing system, activation is insufficient. In addition, the cloud computing system is not being actively introduced because of the difficulty in understanding the cloud computing system technology of the person in charge who intends to introduce the cloud computing system. In this regard, this study presented an effective risk analysis and evaluation method by examining the characteristics, concepts, and models of cloud computing systems and analyzing how these characteristics affect risk analysis and evaluation.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.169-171
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• 2013

Cloud computing provides access to big volumes of data and computational resources through various services. Cloud computing also supports to process these volumes of data using set of computers. Cloud computing can satisfy resource requirements through virtualization technology. Eucalyptus is an open source cloud computing environment helps the users to setup their own private cloud based on virtualization. In this paper, monitoring of virtual machines is explained with the eucalyptus cloud setup.

• The Journal of Society for e-Business Studies
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• v.18 no.3
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• pp.1-15
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• 2013

Recently, many companies have been interested in the cloud computing as a new IT service. They have believed that the technology enables them to save cost and enhance productivity. However, because of the management and operational problems of the technology, they hesitate to adopt the technology into their businesses rapidly. The developed countries in the IT field, such as USA, UK, and Japan, have deployed various policies to promote the use of the cloud computing in their countries. The Korean Government also has started investing a lot of resources to make the technology used widely. This study examines the current status of the Korean Government's technology policies for the cloud computing by using three analysis frameworks, which can be used to identify the government's roles in government-leading technology initiatives. The results show that the Korean Government's current policies have focused on service providers, not service consumers, and focused on public sectors, not private sectors. The unbalanced policies might interfere with the rapid and massive adoption of the cloud computing.

• Journal of Information Technology Services
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• v.11 no.3
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• pp.287-304
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• 2012

Cloud computing, which means a new way of deploying information technology(IT) in organizations as a service and charging per use, has a deep impact on organizations' IT accessibility, agility and efficiency of its usage. More than that, the emergence of cloud computing surpasses a mere technological innovation, making business model innovation possible. We call this innovation realized by could computing a cloud business model. This study develops a comprehensive framework of business model, first, and then defines and analyzes the cloud business model through this framework. This study also examines the case of M-Pesa mobile payment as a cloud business model in which a new value creation and profit realization schemes have been realized and industry value network has changed. Finally, this study discusses the business implications from this new business model.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.12
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• pp.5780-5802
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• 2017

Cloud computing system consists of distributed resources in a dynamic and decentralized environment. Therefore, using cloud computing resources efficiently and getting the maximum profits are still challenging problems to the cloud service providers and cloud service users. It is important to provide the efficient scheduling. To schedule cloud resources, numerous heuristic algorithms such as Particle Swarm Optimization (PSO), Genetic Algorithm (GA), Ant Colony Optimization (ACO), Cuckoo Search (CS) algorithms have been adopted. The paper proposes a Modified Particle Swarm Optimization (MPSO) algorithm to solve the above mentioned issues. We first formulate an optimization problem and propose a Modified PSO optimization technique. The performance of MPSO was evaluated against PSO, and GA. Our experimental results show that the proposed MPSO minimizes the task execution time, and maximizes the resource utilization rate.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.9
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• pp.4280-4300
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• 2017

The fact that cloud computing services have been proposed in recent years, organizations and individuals face with various challenges and problems such as how to migrate applications and software platforms into cloud or how to ensure security of migrated applications. This study reviews the current challenges and open issues in cloud computing, with the focus on autonomic resource management especially in federated clouds. In addition, this study provides recommendations and research roadmaps for scientific activities, as well as potential improvements in federated cloud computing. This survey study covers results achieved through 190 literatures including books, journal and conference papers, industrial reports, forums, and project reports. A solution is proposed for autonomic resource management in the federated clouds, using machine learning and statistical analysis in order to provide better and efficient resource management.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.3
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• pp.70-76
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• 2012

This research tested how the perceived risk and the trust affect the usage intention of the cloud computing. To this end, this research setups a research model and tests it with the statistic tools. In order to build the model, TAM (Technology Acceptance Model) and UTAUT (Unified Theory of Acceptance and Use of Technology) were employed and, the factors such as the perceived risk, the trust and the intention of the cloud computing use were derived. This research finds that the perceived risk does not affect the intention of usage. Also the perceived risk has the negative effect for the trust. Thus this research has the following suggestions.

• International Journal of Computer Science & Network Security
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• v.23 no.10
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• pp.73-80
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• 2023

The recent growth in the use of mobile devices has contributed to increased computing and storage requirements. Cloud computing has been used over the past decade to cater to computational and storage needs over the internet. However, the use of various mobile applications like Augmented Reality (AR), M2M Communications, V2X Communications, and the Internet of Things (IoT) led to the emergence of mobile cloud computing (MCC). All data from mobile devices is offloaded and computed on the cloud, removing all limitations incorporated with mobile devices. However, delays induced by the location of data centers led to the birth of edge computing technologies. In this paper, we discuss one of the edge computing technologies, i.e., cloudlet. Cloudlet brings the cloud close to the end-user leading to reduced delay and response time. An algorithm is proposed for scheduling tasks on cloudlet by considering VM's load. Simulation results indicate that the proposed algorithm provides 12% and 29% improvement over EMACS and QRR while balancing the load.

• Journal of Computing Science and Engineering
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• v.9 no.3
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• pp.119-133
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• 2015

While cloud computing is gaining popularity, diverse security and privacy issues are emerging that hinder the rapid adoption of this new computing paradigm. And the development of defensive solutions is lagging behind. To ensure a secure and trustworthy cloud environment it is essential to identify the limitations of existing solutions and envision directions for future research. In this paper, we have surveyed critical security and privacy challenges in cloud computing, categorized diverse existing solutions, compared their strengths and limitations, and envisioned future research directions.