• 스마트미디어저널
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• 제6권3호
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• pp.21-28
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• 2017

u-fitness 기반 운동관리와 관련된 민감한 신체 정보의 양이 폭발적으로 증가하고 있기 때문에 클라우드 서비스의 활용에 대한 관심이 날로 증가하고 있다. 그러나 클라우드 서버는 자신의 서버에 저장된 정보에 불법적으로 접근할 수 있으며, 누가 그 정보의 소유자인지를 알아낼 수 있고, 스토리지에 저장된 정보 간의 연관성을 불법적으로 추론할 수 있다. 또한 클라우드 서버는 저장된 정보에 대해 수정, 삭제 같은 소유자의 정당한 연산 요청에 대해 불이행할 수 있으며, 자체의 오작동으로 인해 정보를 분실하거나 손상시킬 수 있다. 따라서 우리는 클라우드 서버를 전적으로 신뢰할 수 없기 때문에 클라우드 서버를 사용하기 위해서는 위와 같은 문제들을 해결해야 한다. 우리는 클라우드 컴퓨팅 환경에서 u-Fitness 기반 운동관리를 위한 소유자의 프라이버시를 보장하는 프로토콜을 제안한다. 그리고 제안한 구조가 실제 환경에서 적용 가능함을 보안 분석과 성능 분석을 통해 보인다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권2호
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• pp.312-334
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• 2023

In large-scale computing, cloud computing plays an important role by sharing globally-distributed resources. The evolution of cloud has taken place in the development of data centers and numerous servers across the globe. But the cloud information centers incur huge operational costs, consume high electricity and emit tons of dioxides. It is possible for the cloud suppliers to leverage their resources and decrease the consumption of energy through various methods such as dynamic consolidation of Virtual Machines (VMs), by keeping idle nodes in sleep mode and mistreatment of live migration. But the performance may get affected in case of harsh consolidation of VMs. So, it is a desired trait to have associate degree energy-performance exchange without compromising the quality of service while at the same time reducing the power consumption. This research article details a number of novel algorithms that dynamically consolidate the VMs in cloud information centers. The primary objective of the study is to leverage the computing resources to its best and reduce the energy consumption way behind the Service Level Agreement (SLA)drawbacks relevant to CPU load, RAM capacity and information measure. The proposed VM consolidation Algorithm (PVMCA) is contained of four algorithms: over loaded host detection algorithm, VM selection algorithm, VM placement algorithm, and under loading host detection algorithm. PVMCA is dynamic because it uses dynamic thresholds instead of static thresholds values, which makes it suggestion for real, unpredictable workloads common in cloud data centers. Also, the Algorithms are adaptive because it inevitably adjusts its behavior based on the studies of historical data of host resource utilization for any application with diverse workload patterns. Finally, the proposed algorithm is online because the algorithms are achieved run time and make an action in response to each request. The proposed algorithms' efficiency was validated through different simulations of extensive nature. The output analysis depicts the projected algorithms scaled back the energy consumption up to some considerable level besides ensuring proper SLA. On the basis of the project algorithms, the energy consumption got reduced by 22% while there was an improvement observed in SLA up to 80% compared to other benchmark algorithms.

• 대기
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• 제25권1호
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• pp.117-127
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• 2015

The presences of clouds significantly influence the accuracy of ozone retrievals from satellite measurements. This study focuses on the influence of clouds on Ozone Monitoring instrument (OMI) ozone profile retrieval based on an optimal estimation. There are two operational OMI cloud products; OMCLDO2, based on absorption in $O_2-O_2$ at 477 nm, and OMCLDRR, based on filling in Fraunhofer lines by rotational Raman scattering (RRS) at 350 nm. Firstly, we characterize differences between $O_2-O_2$ and RRS effective cloud pressures using MODIS cloud optical thickness (COT), and then compare ozone profile retrievals with different cloud input data. $O_2-O_2$ cloud pressures are significantly smaller than RRS by ~200 hPa in thin clouds, which corresponds to either low COT or cloud fraction (CF). On the other hand, the effect of Optical centroid pressure (OCP) on ozone retrievals becomes significant at high CF. Tropospheric ozone retrievals could differ by up to ${\pm}10$ DU with the different cloud inputs. The layer column ozone below 300 hPa shows the cloud-induced ozone retrieval error of more than 20%. Finally, OMI total ozone is validated with respect to Brewer ground-based total ozone. A better agreement is observed when $O_2-O_2$ cloud data are used in OMI ozone profile retrieval algorithm. This is distinctly observed at low OCP and high CF.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 춘계학술대회
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• pp.277-280
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• 2011

2006년 클라우드 컴퓨팅(Cloud Computing)의 개념이 등장하고, 최근 IT업계는 이 클라우드 컴퓨팅에 주목하고 있다. 클라우드 시장은 여러 업체의 참여로 날로 증가세에 있고, 근래에는 모바일 클라우드 컴퓨팅(Mobile Cloud Computing)의 가능성이 대두되고 있다. 모바일 시장은 피쳐폰(Feature Phone) 중심에서 아이폰 및 안드로이드기반의 스마트폰으로 급속히 바뀌고 있으며, 2011년 현재 국내 스마트폰 가입자는 1천만명을 넘은 것으로 집계될 만큼 그 성장세는 폭발적이다. 본 연구에서는 현재 스마트폰에서 이용가능한 국내외 모바일 클라우드 서비스의 종류와 실태를 알아보고, 나아가 현 시점에서의 모바일 클라우드 컴퓨팅 문제점과 그 해결책을 제시해보고자 한다.

• 한국컴퓨터정보학회논문지
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• 제24권5호
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• pp.49-58
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• 2019

In this paper, we propose an edge cloud platform architecture for implementing smart factory. The edge cloud platform is one of edge computing architecture which is mainly focusing on the efficient computing between IoT devices and central cloud. So far, edge computing has put emphasis on reducing latency, bandwidth and computing cost in areas like smart homes and self-driving cars. On the other hand, in this paper, we suggest not only common functional architecture of edge system but also light weight cloud based architecture to apply to the specialized requirements of smart factory. Cloud based edge architecture has many advantages in terms of scalability and reliability of resources and operation of various independent edge functions compare to typical edge system architecture. To make sure the availability of edge cloud platform in smart factory, we also analyze requirements of smart factory edge. We redefine requirements from a 4M1E(man, machine, material, method, element) perspective which are essentially needed to be digitalized and intelligent for physical operation of smart factory. Based on these requirements, we suggest layered(IoT Gateway, Edge Cloud, Central Cloud) application and data architecture. we also propose edge cloud platform architecture using lightweight container virtualization technology. Finally, we validate its implementation effects with case study. we apply proposed edge cloud architecture to the real manufacturing process and compare to existing equipment engineering system. As a result, we prove that the response performance of the proposed approach was improved by 84 to 92% better than existing method.

• 천문학회지
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• 제34권1호
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• pp.1-8
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• 2001

We present a fast reduction method of survey data obtained using a single-dish radio telescope. Along with a brief review of classical method, a new method of identification and elimination of negative and positive bad channels are introduced using cloud identification code and several IRAF (Image Reduction and Analysis Facility) tasks relating statistics. Removing of several ripple patterns using Fourier Transform is also discussed. It is found that BACKGROUND task within IRAF is very efficient for fitting and subtraction of base-line with varying functions. Cloud identification method along with the possibility of its application for analysis of cloud structure is described, and future data reduction method is discussed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권8호
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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 Astronomy and Space Sciences
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• 제28권1호
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• pp.13-16
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• 2011

The $CH_3OH$ $4_2-5_1$ E transition was observed toward the Sgr B2 region, including the Principal Cloud and its surroundings. This methanol transition shows an extended emission along the 2'N cloud, which is believed to be colliding with the Principal Cloud and may trigger the massive star formation in this cloud. This extended methanol emission may also suggest that the 2'N cloud is under shocks. We derive total methanol column density $N(CH_3OH)\;=\;2.9{\pm}0.3{\times}10^{14}\;cm^{-2}$ toward the peak position of the extended emission. The fractional abundance of methanol is about 10.9, relative to the estimated total $H_2$ abundance, which is similar to the methanol abundances in quiet gas phase.

• 정보와 통신
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• 제28권10호
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• pp.3-10
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• 2011

The increasing ubiquity of wireless networks and decreasing cost of hardware is fueling a proliferation of mobile devices. These devices are enabling a new revolution in mobile technology, not only running locally on them, but running on cloud as a service as well. From web browsing, email, or video conferencing, presentations to movie and music entertainment or games, multimedia applications, mobile cloud enables providing such diverse applications. Many technologies have been designed to address the limited hardware and performance in thin client PC. However, with the assorted network and graphic condition, those proposed technologies is obligated to alter aim to adapt mobile cloud. In this paper, we provide a survey of client technology on a Server that can be sufficed the requirements of Mobile Cloud. We also analyze each technology and classify with its individual difficulties and challenges.

• 한국컴퓨터정보학회논문지
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• 제22권12호
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• pp.179-186
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• 2017

Managing students' data is a high prioritized duty of the university administration since most of the school affairs are proceed based on that database. Universities have invested in IT assets such as servers, storage, database, and networks. However, continuing investment in IT infrastructure is impossible due to limited budget and rapid changes in the educational environment. As cloud computing diffuse, universities are trying to reduce costs and improve efficiency by increasing server utilization, unlike when physically investing. We designed a hypothetical academic information management system based on cloud computing by utilizing the advanced server virtualization technology. This administrative cloud system allows universities to improve the availability of the system with low cost. The system demonstrates its flexibility of using data resources and immediacy of resumption.