• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.7B
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• pp.1252-1260
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• 1999

The HFC network has a architecture of a star topology in fiber optic trunks, and tree and branch topology is used in the part of coaxial cable. It is well known that the HFC upstream channel is noisy. Ingress, common mode distortion and impulse noise exist in the upstream channel. In order to provide Quality of Service(QoS) to users with real-time data such as voice, video and interactive services, the evolving IEEE 802.14 standard for HFC networks must include an effective priority scheme. The scheme separates and resolves collisions between stations in a priority order. It is important to simulate protocols under a practical environment. The proposed algorithm in this paper is simulated with the assumption that the collision detector made certain mistake due to noises. Simulation results show that the proposed algorithm is more efficient than existing tree-based algorithm under practical environment.

• Journal of Korea Multimedia Society
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• v.12 no.9
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• pp.1201-1209
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• 2009

Recently, the convergence of the telecommunications industry through the development of network media has brought along interactive data services in addition to the traditional broadcast services by providing direct connections between the users and the broadcasters. This can be easily achieved by the combination of existing network technology and multimedia technology, but in reality, as seen in the actual implementation of IPVT, it's difficult to provide satisfactory levels of service to users due to issues of network bandwidth and problems of streaming system. In particular, a network which is able to fully support Qos/QoE, and also a fast enough channel changing technology that is satisfactory to the user, are prerequisites for IPTV success. Therefore this thesis proposes a fast channel changing technique to delivery enhanced IPTV user experience. Recent IP set-top-boxes use only a small portion of the CPU to feed Ethernet packets to the hardware decoder and play them. Thus, by making IP set-top-boxes share cached channel information and content with each other, reducing the load on the server and enhancing the channel changing time is made possible.

• Journal of the Korean Society for information Management
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• v.34 no.1
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• pp.73-110
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• 2017

This study explores the effectiveness and applications of event collection programs, which are integrated programs with event experience and collection experience as a cooperation model that combines school education and library resources as course-related materials. For the purpose, a triangulated analysis with both quantitative and qualitative data was conducted. As a result, This study examined an event collection program's effectiveness which were positive effects on the participated students' reading and perceptions on the roles of their school libraries. The event collection supported the students to self-construct their knowledge by exploring information with the provision of a collection with various materials on a topic, which would be hardly provided within the traditional library subject classification, and that the event collection program could be a useful tool for self-directed reading due to its promotion of interaction, sharing, and participation among materials and the participated students by functional factors of experiential marketing.

• Journal of Korea Multimedia Society
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• v.13 no.7
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• pp.933-942
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• 2010

The convergence of the telecommunication industry through the combination of existing network technology and multimedia technology has brought along interactive data services in addition to the traditional broadcast services by providing direct connections between the users and the broadcasters. The interactive data service technology has developed a network which is able to fully support QoS and also a fast enough channel changing technology that is satisfactory to the user, are prerequisites for IPTV success, to provide satisfactory levels of service to exist users. However the current server-client system can't support all increasing needs of users. To overcome these limitations, P2P based IPTV service is currently under researched. Therefore, this thesis proposes a logical view based copy-ahead technique for P2P IPTV to improve the performance of IPTV system.

• The KIPS Transactions:PartB
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• v.14B no.1 s.111
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• pp.23-32
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• 2007

Nowadays, XML has been favored by many companies internally and externally as a means of sharing and distributing data, due to its open-architectural structure. XML-GL, a graphical query language for document has the advantage of containing both structuring and defining of itself. By incorporating UML an XML document can become object-oriented and can be represented by graphical means. This paper proposes a XML-GL query modeling solution by using UML class diagrams. In order for the modeled objects to be properly restricted, the Object Constraint Language has been defined. This process converts XML documents into Object-Oriented data and combined with UML class diagrams, searches for XML documents can be increased.

• The Journal of the Korea Contents Association
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• v.15 no.12
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• pp.650-659
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• 2015

This study reports on the perspectives of Korean Chinese Japanese students (KS CS JS) on learning English at multi-cultural classrooms in Korea. The participants were 32 KS, 10 CS, and 14 JS in EFL writing classes, and the data comprised open-ended questionnaires and interviews. In analyzing the data, 'Intentional content analysis' and 'Critical discourse analysis' were adopted. The findings show that the learning of English in Korea was supported by 80% of JS, 71.9% of KS, and 50% of CS. The highest satisfaction of JS was caused by rich interactions with others. English speaking was the most difficult area for all the groups. Whereas KS (43.8%) used only Korean, CS and JS used both English and Korean for communication. Most KS (78.1%) hesitated to socialize with foreign students despite their wishes. These findings suggest that a variety of programs should be developed so that students share different cultures and use more English in the multi-cultural Korean context.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.12
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• pp.2911-2918
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• 2014

Nowadays, most Internet servers run on virtual a network which connects each virtual machine, to process large amounts of data on single physical computer. The virtual machines for their own purposes are interconnected to other virtual server systems with various types of operating systems. Each virtual server may share one physical computer resources and operates at a service seamlessly to each other. Sometimes even the virtual machines are implemented using a method that lease the physical IT resources without purchasing physical server. Therefore, a virtual switch is needed to improve the performance when a large number of virtual machines operate on physical server. In this study, the implementation and investigation was performed for the virtual switches, OpenvSwitch and DPDKvSwitch, in order to provide the necessary high-performance cloud services to creative business.

• The KIPS Transactions:PartB
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• v.13B no.2 s.105
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• pp.139-148
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• 2006

In the collaborative product design environment, the communication between designers is important to capture design intents and to share a common view among the different but semantically similar terms. The Semantic Web supports integrated and uniform access to information sources and services as well as intelligent applications by the explicit representation of the semantics buried in ontology. Ontologies provide a source of shared and precisely defined terms that can be used to describe web resources and improve their accessibility to automated processes. Therefore, employing ontologies on assembly modeling makes assembly knowledge accurate and machine interpretable. In this paper, we propose a framework of semantic assembly modeling using ontologies to share design information. An assembly modeling ontology plays as a formal, explicit specification of a shared conceptualization of assembly design modeling. In this paper, implicit assembly constraints are explicitly represented using OWL (Web Ontology Language) and SWRL (Semantic Web Rule Language). The assembly ontology also captures design rationale including joint intent and spatial relationships.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.1
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• pp.125-129
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• 2010

Stateless computing supports a mobility of computing environment easily. It is becoming a major technology for securing personal user's information on shared computing environment. With the advance of virtualization technology and cloud computing, stateless computing is an essential part of personal computing environment connectivity (user's setting and data is stored in remote server or some storage, and it can be restored at any computing environment) In this paper, we propose uPC player that supports stateless computing execution environment on Windows. uPC player provides Windows operating system to user by using an uPC OS virtualization module. In this paper, we leverage how uPC player is designed and implemented for supporting a stateless computing execution environment. uPC player provides a desktop switch between host-system execution environment and uPC virtual execution environment. And it needs just one second for loading uPC virtual execution environment by using OS virtualization-based technique.

• Journal of Information Management
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• v.36 no.3
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• pp.71-95
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• 2005

Interoperability and collaborations have become essential factors for developing a digital library. TEL, the European Library, is a new Pan-European service which gives access to the combined resources of the national libraries in Europe, and also TEL is the name of a project to implement TEL service. The vision of TEL stems from the characteristics that the national libraries offer, which is the comprehensiveness of collection, the national libraries' holdings of outstanding historical and special collection, reliability of information and high quality. Moreover, the national libraries are in a unique position to invest in creating added value to the digitized documents and to show the cultural diversity between EU members. From the viewpoint of digital library techniques, TEL explored some advanced methodologies to guarantee the interoperability between heterogenious collections and libraries. In this study, we examine the development of TEL including publisher relations, metadata developments, and retrieval features.