• 한국지구과학회지
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• 제43권4호
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• pp.498-510
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• 2022

Cloud-aerosol interactions are one of the paramount but least understood forcing factors in climate systems. Generally, an increase in the concentration of aerosols increases the concentration of cloud droplet numbers, implying that clouds tend to persist for longer than usual, suppressing precipitation in the warm boundary layer. The cloud lifetime effect has been the center of discussion in the scientific community, partly because of the lack of cloud life cycle observations and partly because of cloud problems. In this study, the precipitation susceptibility (S_o) matrix was employed to estimate the aerosols' effect on precipitation, while the non-aerosol effect is minimized. The S_o was calculated for the typical coupled, well-mixed maritime stratocumulus decks and giant cloud condensation nucleus (GCCN) seeded clouds. The GCCN-artificially introduced to the marine stratocumulus cloud decks-is shown to initiate precipitation and reduces S_o to approximately zero, demonstrating the cloud lifetime hypothesis. The results suggest that the response of precipitation to changes in GCCN must be considered for accurate prediction of aerosol-cloud-precipitation interaction by model studies

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권7호
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• pp.3026-3049
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• 2016

Cloud computing promises high performance and cost-efficiency. However, most cloud infrastructures operate at a low utilization, which greatly adheres cost effectiveness. Previous works focus on seeking efficient virtual machine (VM) consolidation strategies to increase the utilization of virtual resources in production environment, but overlook the under-utilization of backup virtual resources. We propose a heuristic time sharing policy of backup VMs derived from the restless multi-armed bandit problem. The proposed policy achieves increasing backup virtual resources utilization and providing high availability. Both the results in simulation and prototype system experiments show that the traditional 1:1 backup provision can be extended to 1:M (M≫1) between the backup VMs and the service VMs, and the utilization of backup VMs can be enhanced significantly.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2012년도 추계학술발표대회
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• pp.239-240
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• 2012

When users access to use the computing resources in the cloud, they expect specific quality of service (QoS) which should be guaranteed by the service provider. Meanwhile, the service provider should adopt proper schemes to enhance the resource utilization. In this thesis, we propose the MapChem-Broker which aims to satisfy users' QoS requirements as well as enhance the resource utilization by controlling the provision of VM resources in the cloud. On the experimental cloud testbed, we compare the proposed scheme with an existing one for VM resource provisioning. Results show that the proposed scheme outperforms the existing one.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2020년도 추계학술발표대회
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• pp.78-79
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• 2020

최근 하드웨어의 성능 및 소프트웨어 기술이 비약적으로 발전하면서 컴퓨팅을 위한 인프라 환경이 클라우드 기술 기반으로 활발하게 연구, 개발되고 있다. 이에 본 논문에서는 슈퍼컴퓨터로 대표되는 고성능 컴퓨팅을 분야에서 클라우드 기반 인프라 및 서비스를 제공하기 위한 KI Cloud 플랫폼을 소개한다. KI Cloud 플랫폼은 VM 기반으로 IaaS 서비스를 제공하고, 컨테이너 기술을 기반으로 HPC 사용자를 위한 PaaS 서비스를 제공하는 통합 플랫폼으로 설계 및 개발되었다.

• Journal of Internet Technology
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• 제19권6호
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• pp.1741-1752
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• 2018

The best known software developers all offer cloud storage services. Microsoft offers Onedrive to its users, Apple offers iCloud Drive and Google offers Google Drive or GDrive. The battle between these software developers is ongoing and they will always strive to give the best services to their users. It is not only technology that is evolving, however, but also ways in which security can be breached and data abused. The security of information on the Internet is increasingly at risk and there are many threats to cloud storage platforms. This research used the mobile forensics approach to help in identifying and analyzing user behavior that may occur while using GDrive application for cybercrime. The novelty of comparison and analyzing methods performed in this research can help to find remnant data from all activities performed by GDrive users in Android smartphones. Hence, this proposed method can assist investigators in finding remnant data on GDrive client and can provide knowledge for legal practitioners.

• 융합보안논문지
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• 제13권4호
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• pp.93-100
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• 2013

2012년 시스코가 발간한 '시스코 글로벌 클라우드 인덱스 2011-2016'에 따르면 전 세계 데이터 센터 트래픽은 2016년까지 4배 가량 증가하고, 클라우드 트래픽은 6배 가량 증가할 것이라고 전망했다. 이처럼 급증하는 데이터 센터의 트래픽 대부분은 데이터 센터 및 클라우드 컴퓨팅 워크로드로 인해 발생된다. 국방부는 지난 2010년, '2012 정보화사업계획'의 일환으로 2014년까지 클라우드 컴퓨팅 기술이 포함된 국방통합정보관리소를 구축하기로 결정하였고, 현재 추진 중에 있다. 국방통합정보관리소(메가 센터) 구축 시 반드시 고려해야 할 요소 중 하나가 클라우드 컴퓨팅 트래픽이다. 국방 클라우드 컴퓨팅 시스템이 구축되고 난 이후 국방 클라우드 트래픽은 꾸준히 증가할 것이다. 본 논문에서는 국방 클라우드 컴퓨팅 시범체계를 모델로 CloudAnalyst 시뮬레이션 툴을 이용하여 클라우드 트래픽 증가에 따른 서비스 가용성을 분석하였다. 3개 시나리오를 구성하여 시뮬레이션 수행 결과, 현재 시점에서 2016년까지 예측되는 클라우드 트래픽 성장률만큼 클라우드 워크로드가 증가하여도 국방 클라우드 시범체계는 서비스 가용성을 충족한다는 결론을 도출하였다.

• Journal of Multimedia Information System
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• 제2권1호
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• pp.143-152
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• 2015

Multimedia services in the cloud have become a popular trend in the big data environment. However, how to efficiently schedule a large number of multimedia services in the cloud is still an open and challengeable problem. Current cloud-based scheduling algorithms exist the following problems: 1) the content of the multimedia is ignored, and 2) the cloud platform is a known parameter, which makes current solutions are difficult to utilize practically. To resolve the above issues completely, in this work, we propose a novel distributed multimedia scheduling to satisfy the objectives: 1) Develop a general cloud-based multimedia scheduling model which is able to apply to different multimedia applications and service platforms; 2) Design a distributed scheduling algorithm in which each user makes a decision based on its local information without knowing the others' information; 3) The computational complexity of the proposed scheduling algorithm is low and it is asymptotically optimal in any case. Numerous simulations have demonstrated that the proposed scheduling can work well in all the cloud service environments.

• Journal of Information Processing Systems
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• 제10권1호
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• pp.132-144
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• 2014

Information always comes with security and risk problems. There is the saying that, "The tall tree catches much wind," and the risks from cloud services will absolutely be more varied and more severe. Nowadays, handling these risks is no longer just a technology problem. So far, a good deal of literature that focuses on risk or security management and frameworks in information systems has already been submitted. This paper analyzes the causal risk factors in cloud environments through critical success factors, from a business perspective. We then integrated these critical success factors into a business model for information security by mapping out 10 principles related to cloud risks. Thus, we were able to figure out which aspects should be given more consideration in the actual transactions of cloud services, and were able to make a business-level and general-risk control model for cloud computing.

• International Journal of Computer Science & Network Security
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• 제22권2호
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• pp.290-296
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• 2022

Big Data is a data analysis technology empowered by late advances in innovations and engineering. In any case, big data involves a colossal responsibility of equipment and handling assets, making reception expenses of big data innovation restrictive to little and medium estimated organizations. Cloud computing offers the guarantee of big data execution to little and medium measured organizations. Big Data preparing is performed through a programming worldview known as MapReduce. Normally, execution of the MapReduce worldview requires organized joined stockpiling and equal preparing. The computing needs of MapReduce writing computer programs are frequently past what little and medium measured business can submit. Cloud computing is on-request network admittance to computing assets, given by an external element. Normal arrangement models for cloud computing incorporate platform as a service (PaaS), software as a service (SaaS), framework as a service (IaaS), and equipment as a service (HaaS).

• 융합정보논문지
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• 제8권6호
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• pp.173-186
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• 2018

클라우드 서비스가 확대되고 있지만, 많은 이용자들은 클라우드 서비스의 도입에 어려움을 겪고 있다. 이는 이용자 입장에서 어떤 클라우드 서비스를 신뢰할 수 있는지에 대한 정보가 없기 때문이다. 클라우드 서비스수준협약(클라우드 SLA)은 클라우드 서비스를 제공하는 공급자와 이용자간에 서비스의 품질과 성능 등을 포함한 정성적인 지표와 정량적 지표를 이용하여 협의하는 것이다. 이 연구에서는 클라우드 서비스 사업자의 서비스 수준을 향상하고 이용자를 보호하기 위해 국내 클라우드 산업에 적용할 수 있는 클라우드 SLA를 위한 프레임워크 제안하고 이를 이용하여 국내 클라우드 산업에 적용할 수 있는 클라우드 SLA의 세부 구성항목을 도출하고자 한다. 이를 통해 정부의 "클라우드컴퓨팅 발전 및 이용자 보호에 관한 법률" 체계하의 클라우드 서비스 제공자와 이용자간의 신뢰도 향상을 위한 정책적 활용은 물론 궁극적으로 국내 클라우드 서비스의 품질 성능 수준 향상 및 이용자 신뢰기반 조성을 통해 클라우드 서비스의 활성화를 기대한다.