• Transactions of the KSME C: Technology and Education
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• v.1 no.1
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• pp.33-38
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• 2013

Offshore drilling refers to a mechanical process where a wellbore is drilled through a seabed. It is typically carried out in order to explore for and subsequently extract petroleum which lies in rock formations beneath the seabed. There are many different type of facilities from which offshore drilling operations take place. These include bottom founded drilling rigs, combined drilling and production facilities either bottom founded or floating platforms, and deepwater mobile offshore drilling units including semi-submersibles and drillships. These are capable of operating in water depths up to 3,000 m. In this paper, we introduce the drilling system, which is mounted on the offshore drilling facilities.

• Journal of Korean Society of Steel Construction
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• v.29 no.2
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• pp.99-110
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• 2017

This paper presents the study of the bending behavior of mooring chain links for keeping the position of the offshore floating structures. In general, chain links have been thought as the axial members due to the fundamental boundary condition. But, the flexural stiffness can be induced to the contact surface between chain links when friction occurs at the surface of the chain links due to high tensile force. Especially, the mooring chains for offshore floating platforms are highly tensioned. If the floater suffers rotational motion and the mooring chain links are highly tensioned, the rotation between contact links, induced by the floater rotation, generates the bending moment and relevant stresses due to the unexpected bending stiffness. In 2005, the mooring chain links for the Girassol Buoy Platform were failed after just 5 months after facility installation, and the accident investigation research concluded the chain failure was mainly caused by the fatigue due to the unexpected bending stress fluctuation. This study investigates the pattern of the induced bending stiffness and stresses of the highly tensioned chain links by nonlinear finite element analysis.

• The Journal of the Korea Contents Association
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• v.17 no.10
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• pp.686-695
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• 2017

Advancement in media technology has brought about changes to the scene of ethnic minority media. As now platforms started to convey information about mother country as well as new nation. This study examines the actual status of Korean minority broadcasting companies and promoting its competitiveness through interviews and survey of media companies. The result shows that Korean ethnic broadcasting market is facing severe competition and decrease in profit by entering Korean terrestrial TV companies. Therefore, supports of Korean government is essential for promoting competitiveness of Korean minority media companies. Through voces of Korean minority media companies, we will search for find out solutions : support of production cost, supply of Korean programs, and training programs for promoting the capability of production staffs.

• International Journal of Contents
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• v.13 no.2
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• pp.29-34
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• 2017

Cloud computing is becoming an effective and efficient way of computing resources and computing service integration. Through centralized management of resources and services, cloud computing delivers hosted services over the internet, such that access to shared hardware, software, applications, information, and all resources is elastically provided to the consumer on-demand. The main enabling technology for cloud computing is virtualization. Virtualization software creates a temporarily simulated or extended version of computing and network resources. The objectives of virtualization are as follows: first, to fully utilize the shared resources by applying partitioning and time-sharing; second, to centralize resource management; third, to enhance cloud data center agility and provide the required scalability and elasticity for on-demand capabilities; fourth, to improve testing and running software diagnostics on different operating platforms; and fifth, to improve the portability of applications and workload migration capabilities. One of the key features of cloud computing is elasticity. It enables users to create and remove virtual computing resources dynamically according to the changing demand, but it is not easy to make a decision regarding the right amount of resources. Indeed, proper provisioning of the resources to applications is an important issue in IaaS cloud computing. Most web applications encounter large and fluctuating task requests. In predictable situations, the resources can be provisioned in advance through capacity planning techniques. But in case of unplanned and spike requests, it would be desirable to automatically scale the resources, called auto-scaling, which adjusts the resources allocated to applications based on its need at any given time. This would free the user from the burden of deciding how many resources are necessary each time. In this work, we propose an analytical and efficient VM-level scaling scheme by modeling each VM in a data center as an M/M/1 processor sharing queue. Our proposed VM-level scaling scheme is validated via a numerical experiment.

• The Journal of the Korea Contents Association
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• v.13 no.8
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• pp.28-35
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• 2013

Recently, cloud data management has been actively studied along with the development of a cloud computing technology that can process large amounts of data at a lower cost. However, the existing cloud computing platforms do not guarantee interoperability according to the construction environments of users because they do not provide technical and political openness. In other words, in order for users to receive the related services, they use services provided by only one vendor. In this paper, we design and implement a storage interface that supports the international standard CDMI in order to retrieve, update, and delete data in could environments. These interfaces provide the functionality required for developers who want to build and use the cloud storage without special restrictions. In addition, we verify the operability and usability of CDMI international standard through the implementation of the proposed system.

• The Journal of the Korea Contents Association
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• v.9 no.10
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• pp.22-31
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• 2009

Although the amount of UCC(user created content) rapidly grows nowadays, there are various problems in authoring, distribution and management of this abundant content because the platforms for fabrication and replaying content are not compatible and the authoring environments are not sufficiently interoperable with other site or with each other. In this paper, we propose a CPMS(content publication and management system) scheme improved in interoperability to solve these problems, and we design a novel system enhancing the efficiency and speed of content distribution and management by minimizing the repetitions in the processes of production, reshaping, and publication. Moreover the proposed system adopts an improved content management technology by changing from simple point-to-point method to the centralized distribution method, and as for the service scheme, we change from the site link method to the database link method, and we also take duplex interlink scheme instead of simplex one. We finally compare the proposed system to the conventional ones as points of view of compatibility and interoperability to prove the improved performance of our system.

• The Journal of the Korea Contents Association
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• v.16 no.5
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• pp.1-12
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• 2016

Internet of Things (IoTs) technologies have been computerized information generated from a variety of objects and humans, and have been applied to various fields by connecting via the Internet. In order to compensate for the marginal characteristics of IoT smart devices, such as low-power, limited processing and capacities, combining IoT and cloud computing technologies is now established itself as one of the paradigms. In this paper, we look at the definition, features and services of IoT and cloud computing technology, and we investigate and analyze the conversing needs of IoT and could computing, existing conversion paradigms, convergence cases, and platforms. In results, there are challenges to be solved, even though the cloud technologies complement a number of restrictions of IoT and offer various advantages such as scalability, interoperability, reliability, efficiency, availability, security, ease of access, ease of use, and reduced cost of deployment. We analyze the new research issues of convergence paradigm, and finally suggest a research challenges for convergence.

• Journal of Information Technology Services
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• v.11 no.3
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• pp.161-175
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• 2012

A novel concept of ICT based service, which is called N-device service, is proposed and implemented in the form of N-device smart education services. The N-device services are different from the existing N-screen services in terms of the number of devices a user is using for a specific service at the same time. A N-device service consists of several smart devices which are different in size, software and hardware platform, mobility, manufacturer and the like by fully utilizing the characteristic of each device. The major and unique features of N-device services are analyzed and depicted in a strict way. Those are shared role for each device, service by configurable device, one sensor multiple use, real-time data sharing, role shifting and new market creation. It is turned out that the N-device service is more human centric compared with existing ICT based services and can give richer digital experience to users because non-existent services become possible with the new concept. However, there exist several barriers to be implemented and commercialized in the real world. Those include high development cost and time, small market and different application platforms of devices. These barriers can be overcome by technical advances and cooperation between relevant parties. The smart education is very prominent area, in which the novel concept can be applied with high priority because Korean government announced its plan to boost up new educational services with big budget and these are acceptable by enthusiastic Korean parents and students. That's why the N-device service is implemented in the education area, which is called as "livessam(live teacher)," with four smart devices, IPTV, tablet PC, PC and smart phone. By providing both detailed service scenario and techniques, we shows that the novel education service is technically feasible and acceptable by teachers and students.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.5
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• pp.1105-1110
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• 2000

In the past high cost and complex system configuration often discouraged hospitals from building teleradiology system or PACS(Picture Archiving and Communication System). But new standard platforms enable us to construct the same system with very low cost and simple configurations. internet as a communication channel made us overcome the regional limit and communication cost, and WWW technologies simplified the complex problems on the software developments, configurations and installations. So whoever has a Web browser to access internet can review medical images at anywhere. And we adopted DICOM technology which is a standard for medical imaging, thus we could resolve the interface problems among medical imaging systems such as modalities or archives. The implementation is comprised of three part DICOM/WWW interface subsystem, image format conversion subsystem and viewing applets which are displayed on users WWW browsers. In addition, Teleradiology intrenet PACS system includes DICOM converter that non-DICOM file format converts standard file format.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.5
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• pp.1097-1103
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• 2015

In order to build network infrastructure to implement the aforementioned advantages enabling smart device users to work anywhere, professional support and expensive VPN devices are required. This is a barrier to supplying VPN devices to small and medium-sized institutes. To address this issue, this study aims to implement OpenVPN, OpenSSH and iproute based on the OpenWRT platform which is an embedded OS for open networks in affordable open wired/wireless gateway H/W platforms to support the inter-network VPN. In addition, the network environment can be maintained optimal by applying a "multi-queuing real-time traffic shaping technology" to VPN tunnels, although channel quality changes.