• 한국콘텐츠학회논문지
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• 제14권9호
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• pp.45-53
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• 2014

본 연구에서는 차세대 ITS로 주목받고 있는 국내외 C-ITS 기술 동향을 현재 국내에서 진행 중인 프로젝트를 중심으로 분석하였으며, 해외 선진국들의 추진 사례를 바탕으로 국내 C-ITS 정책이 기존의 ITS 인프라와의 연계 모색이 미흡함을 지적한다. 이를 극복하기 위한 방안으로, 기존 ITS 인프라가 C-ITS에 대응이 가능하도록 세 가지 방향성을 제시한다. 첫째, 기존 인프라 설비의 성능을 고도화하고 자동화하는 기술을 개발(Performance-enhanced ITS)하고, 둘째, 능동형 센서 및 융합 센서를 개발하여 V2X 통신 기술과 더불어 선제적 안전 운행 지원 기술을 개발(Safety-enhanced ITS)하며, 셋째 Nomadic Device의 보급으로 발생하는 비정형 교통 데이터를 기존 ITS 설비로 수집한 데이터와 융합하여 고급 교통정보를 생성하는 기술 개발(Cloud-ITS)이다. 이와 같이 기존 ITS 인프라에 V2X 통신 환경에 필요한 기능을 추가하고 효율적인 유지관리 기술을 개발한다면 C-ITS에서 추구하는 차량과 차량, 차량과 노변 장비와의 상호 협력적인 기술 기반이 조성되고, 예산의 중복 투자 방지가 가능해져 C-ITS 도입 효과를 극대화할 수 있을 것으로 기대한다.

• 한국지구과학회지
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• 제32권4호
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• pp.402-410
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• 2011

본 논문에서는 IRAS 07280-1829 적외선원과 이를 둘러싸고 있는 분자운에 대해 수행된 $^{12}CO$와 $^{13}CO$ 1-0 분자선 관측결과와 기존의 적외선 자료를 이용하여 이 적외선원의 생성환경에 관해 연구하였다. 관측자료로부터 얻어진 적외선원의 파장별 에너지분포의 기울기(${\alpha}$=1.16)와 복사온도(145 K), 그리고 광도(${\sim}2.9{\times}10^4L_{\odot}$)는 이 적외선 천체가 CLASS I형의 중량급원시성임을 의미한다. 이 적외선원방향에서 관측된 두 CO 분자선에서 보이는 넓은 속도 성분은 분자분출류의 존재를 암시한다. 적외선원을 감싸고 있으리라 짐작되는 분자운A에서 측정된 여기온도는 9-22 K, 질량은 약 ~180 $M_{\odot}$인 것으로 보아 이 분자운이 전형적인 적외선 암흑분자운(Infrared-dark clouds)의 물리적 특성을 가짐을 보았다. 이 분자운의 질량은 비리알 질량보다 10배 이상 작은 값으로 계산되었는데 이것은 여기에 어린 원시성이 이미 생성되고 있다는 관측사실에 모순된다. 이는 아마도 분자운A가 교란운동(turbulence) 혹은 강한 자기장에 의해 지배되는 환경 가운데에 중량급원시성 IRAS 07280-1829을 생성하고 있음을 의미하는 것 일수도 있는 것으로 해석하였다.

• 한국지구과학회지
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• 제30권1호
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• pp.58-68
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• 2009

몬순 기간에 구름의 복사 강제력의 영향을 파악하기 위하여 1998년 4월부터 9월까지 International Satellite Cloud Climatology Project (ISCCP) 구름자료와 GEWEX Asian Monsoon Experiment (GAME) 재분석 자료를 입력 자료로 복사 모델을 수행하여 3차원의 장파 복사 플럭스를 구하였다. 구름에 의한 대기 복사 가열은 구름을 포함한 평균 대기와 맑은 대기에서의 복사 가열율의 차이를 이용하여 계산하였다 구름에 의한 복사 가열율이 아시아 몬순에 미치는 영향을 중점적으로 살펴보았다. 구름에 의한 복사 가열은 인도양에서 최대를 티벳 고원에서 최소를 나타내어, 남북으로 차등 가열의 경도를 나타내었다. 이러한 차등 가열이 대기 순환의 최대 원인임을 고려해볼 때, 인도양과 티벳 고원에서의 구름에 의한 차등 가열의 경도는 해들리 타입의 남북 몬순 순환을 강화시키고 있다. 또한 운정에서의 가열, 운저에서의 냉각의 형태로 나타나는 구름의 복사 가열 분포는, 대기의 불안정성을 높여서 몬순 순환을 증대시킬 수 있는 역할을 하고 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권4호
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• pp.1520-1542
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• 2020

Traditional software testing typically uses many physical resources to manually build various test environments, resulting in high resource costs and long test time due to limited resources, especially for small enterprises. Cloud computing can provide sufficient low-cost virtual resources to alleviate these problems through the virtualization of physical resources. However, the provision of various test environments and services for implementing software testing rapidly and conveniently based on cloud computing is challenging. This paper proposes a multilayer cloud testing model based on cloud computing and implements a hybrid cloud testing system based on virtual machines (VMs) and networks. This system realizes the automatic and rapid creation of test environments and the remote use of test tools and test services. We conduct experiments on this system and evaluate its applicability in terms of the VM provision time, VM performance and virtual network performance. The experimental results demonstrate that the performance of the VMs and virtual networks is satisfactory and that this system can improve the test efficiency and reduce test costs through rapid virtual resource provision and convenient test services.

• Journal of information and communication convergence engineering
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• 제8권4호
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• pp.427-432
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• 2010

The fast-emerging of cloud computing technology today has sufficiently benefited its wide range of users from individuals to large organizations. It carries an attractive characteristic by renting myriad virtual storages, computing resources and platform for users to manipulate their data or utilize the processing resources conveniently over Internet without the need to know the exact underlying infrastructure which is resided remotely at cloud servers. However due to the loss of direct control over the systems/applications, users are concerned about the risks of cloud services if it is truly secured. In the literature, there are cases where attackers masquerade as cloud users, illegally access to their accounts, by stealing the static login password or breaking the poor authentication gate. In this paper, we propose a two-factor authentication framework to enforce cloud services' authentication process, which are Public Key Infrastructure (PKI) authentication and mobile out-of-band (OOB) authentication. We discuss the framework's security analysis in later session and conclude that it is robust to phishing and replay attacks, prohibiting fraud users from accessing to the cloud services.

• 한국IT서비스학회지
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• 제11권1호
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• pp.155-171
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• 2012

With the continuous and outstanding development of information technology(IT), human being is coming to the new computing era which is called cloud computing. This era brings lots of huge benefits also at the same time release the resources of IT infrastructure and data boom for man. In the future no longer, most of IT service providers, enterprises, organizations and systems will adopt this new computing model. There are three main deployment models in cloud computing including public cloud, private cloud and hybrid cloud; each one also has its own cons and pros. While implementing any kind of cloud services, customers have to choose one of three above deployment models. Thus, our paper aims to represent a practical framework to help the adopter select which one will be the best suitable deployment model for their requirements by evaluating each model comprehensively. The framework is built by applying the analytic hierarchy process(AHP), namely benefit-cost-opportunity-risk(BCOR) model as a powerful and effective tool to serve the problem. The gained results hope not only to provide useful information for the readers but also to contribute valuable knowledge to this new area. In addition, it might support the practitioners' effective decision making process in case they meet the same issue and have a positive influence on the increase of right decision for the organization.

• 대한원격탐사학회지
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• 제15권3호
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• pp.239-251
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• 1999

The elimination process of cloud-contaminated pixels is one of important steps before obtaining the accurate parameters of land and ocean surface from AVHRR imagery. We developed a 6step threshold method to detect the cloud-contaminated pixels from NOAA-14/AVHRR datime imagery over land using different combination of channels. This algorithm has two phases : the first is to make a cloud-free characteristic data of land surface using compositing techniques from channel 1 and 5 imagery and a dynamic threshold of brightness temperature, and the second is to identify the each pixel as a cloud-free or cloudy one through 4-step threshold tests. The merits of this method are its simplicity in input data and automation in determining threshold values. The threshold of infrared data is calculated through the combination of brightness temperature of land surface obtained from AVHRR imagery, spatial variance of them and temporal variance of observed land surface temperature. The method detected the could-comtaminated pixels successfully embedded inthe NOAA-14/AVHRR daytime imagery for the August 1 to November 30, 1996 and March 1 to July 30, 1997. This method was evaluated through the comparison with ground-based cloud observations and with the enhanced visible and infrared imagery.

• International Journal of Computer Science & Network Security
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• 제24권6호
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• pp.153-160
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• 2024

Information technology plays an important role in healthcare. The cloud has several applications in the fields of education, social media and medicine. But the advantage of the cloud for medical reasons is very appropriate, especially given the large volume of data generated by healthcare organizations. As in increasingly health organizations adopting towards electronic health records in the cloud which can be accessed around the world for various health issues regarding references, healthcare educational research and etc. Cloud computing has many advantages, such as "flexibility, cost and energy savings, resource sharing and rapid deployment". However, despite the significant benefits of using the cloud computing for health IT, data security, privacy, reliability, integration and portability are some of the main challenges and obstacles for its implementation. Health data are highly confidential records that should not be made available to unauthorized persons to protect the security of patient information. In this paper, we discuss the privacy and security requirement of EHS as well as privacy and security issues of EHS and also focus on a comprehensive review of the current and existing literature on Electronic health that uses a variety of approaches and procedures to handle security and privacy issues. The strengths and weaknesses of some of these methods were mentioned. The significance of security issues in the cloud computing environment is a challenge.

• International Journal of Computer Science & Network Security
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• 제21권11호
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• pp.345-353
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• 2021

Cloud computing represent a new era of computing that's forms through the combination of service-oriented architecture (SOA), Internet and grid computing with virtualization technology. Virtualization is a concept through which every cloud is enable to provide on-demand services to the users. Most IT service provider adopt cloud based services for their users to meet the high demand of computation, as it is most flexible, reliable and scalable technology. Energy based performance tradeoff become the main challenge in cloud computing, as its acceptance and popularity increases day by day. Cloud data centers required a huge amount of power supply to the virtualization of servers for maintain on- demand high computing. High power demand increase the energy cost of service providers as well as it also harm the environment through the emission of CO₂. An optimization of cloud computing based on energy-performance tradeoff is required to obtain the balance between energy saving and QoS (quality of services) policies of cloud. A study about power usage of resources in cloud data centers based on workload assign to them, says that an idle server consume near about 50% of its peak utilization power [1]. Therefore, more number of underutilized servers in any cloud data center is responsible to reduce the energy performance tradeoff. To handle this issue, a lots of research proposed as energy efficient algorithms for minimize the consumption of energy and also maintain the SLA (service level agreement) at a satisfactory level. VM (virtual machine) consolidation is one such technique that ensured about the balance of energy based SLA. In the scope of this paper, we explore reinforcement with fuzzy logic (RFL) for VM consolidation to achieve energy based SLA. In this proposed RFL based active VM consolidation, the primary objective is to manage physical server (PS) nodes in order to avoid over-utilized and under-utilized, and to optimize the placement of VMs. A dynamic threshold (based on RFL) is proposed for over-utilized PS detection. For over-utilized PS, a VM selection policy based on fuzzy logic is proposed, which selects VM for migration to maintain the balance of SLA. Additionally, it incorporate VM placement policy through categorization of non-overutilized servers as- balanced, under-utilized and critical. CloudSim toolkit is used to simulate the proposed work on real-world work load traces of CoMon Project define by PlanetLab. Simulation results shows that the proposed policies is most energy efficient compared to others in terms of reduction in both electricity usage and SLA violation.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.275-278
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• 2002

The recognition of the natural background radiation is important not only for radiological education but also for the promotion of people's scientific view about radiation. We made a "room" on the web showing natural background radiation as part of a VRM (Virtual Radiation Museum). The "room" shows the video images of the tracks of charged particles from natural background radiation, alpha and beta ray track from known sources using a Large Scale Diffusion Cloud Chamber. The purpose of this study is to make clear the origin of a kind of track (named A-track) which is thick and easy to recognize with the length less than several cm in the cloud chamber, and to make numerical explanation of its counting rate. The study was carried out using a Large Scale Diffusion Cloud Chamber (Phywe, Germany) installed in the Niigata Science Museum. The Model RNC (Pylon Electronics, Canada) was used as Rn-222 source. Ra-226 activity in RNC was 111.6 Bq calibrated with NIST protocol. Rn-222 gas was injected into the cloud chamber. Continuous video recording with use of Digital Handycam (SONY, Japan) was carried out for 360 min. after injection of Rn-222 gas. The number of alpha-ray track (alpha track) in the video images was analyzed. The growth and decay curve of the total activity of Rn-222 and its alpha emitting progeny were calculated and compared with the count of the alpha tracks. As a result the alpha tracks formed by Rn-222 injection resemble A-Tracks. The relationship between A-track in the cloud chamber and atmospheric Rn is discussed.