• Journal of Korea Multimedia Society
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• v.7 no.2
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• pp.187-193
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• 2004

Wireless networks play a very important role in communications today. For example, wireless networks today provide from the basic services like e-mail and FTP to the multimedia applications like Web service. It is obvious that QoS requirements to these diverse applications over wireless networks will continue as in wired networks. Much research has been done to develop QoS supporting algorithms on Internet. But due to the limited bandwidth and varying channel states of the wireless networks, it is difficult to support differentiated service over wireless networks. In this paper we propose the modified wireless token ring protocol supporting QoS to the real-time traffic service node over Internet environments in which non-real-time and real-time traffic service nodes coexist. In the proposed algorithm, the real-time traffic service node gets the priority to take token over the non-real-time traffic service node. So the proposed algorithm support quick transmission of the real-time traffic service node. And this advantage can be obtained with minor modification of the legacy wireless token ing protocol to support QoS. We also consider the lost token recovery mechanism.

• Journal of the Korea Convergence Society
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• v.9 no.8
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• pp.33-39
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• 2018

In the Internet of Things (IoT) era, objects are connected to each other by wired and wireless networks, and information is exchanged whenever necessary. Channel and network environments change over time; thus, a carrier sensing function that identifies whether signals containing information are present in the channel is essential. The carrier sensing circuit of a wireless communication system determines the receiver sensitivity, and the receiver sensitivity is closely related to the service coverage and service quality of the system. As the receiver sensitivity decreases, the service coverage increases but it becomes sensitive to noise. However, as the receiver sensitivity increases, the service coverage decreases but it becomes insensitive to the noise. Therefore, carrier sensing design and optimization are very important from the viewpoint of the receiver sensitivity and noise sensitivity. This paper proposes an effective carrier sensing technique from the viewpoint of the receiver sensitivity for the long range IoT.

• Journal of Internet Computing and Services
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• v.3 no.5
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• pp.63-72
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• 2002

Recently, construction of infrastructure for mobile internet has been progressed very rapidly including various mobile terminals. Therefore, many service models on mobile internet have been appeared and the methods to reuse the existing huge wired web contents have been studied with many-sided ways. In this paper we classify the related technologies published up to now and make a comparison among their strengths and weaknesses, For this purpose, Technologies are classified according to authoring time, authoring place, and processing level of contents. The automatic contents re-authoring technology is examined in particular and we propose a new contents re-authoring method in which the function of compressing selected information is added in order to complement the existing contents re-authoring methods.

• The Journal of Information Technology
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• v.8 no.3
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• pp.131-142
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• 2005

The principles on which the Internet was designed and has evolved were first laid out in an explicit way 20 years age. The basic principle is that in layered communications network such as the Internet, functions should always be implemented at the end systems whenever the option exists. This applies to all functions that can be implemented either in the network or at the end systems. End-to-end arguments have recently been reexamined as the Internet and its uses have evolved, and a new set of requirements has begun to emerge. In addition to these, it add a new, and perhaps more important, requirement to this list in the case of heterogeneous networks: the proliferation of unpredictable wireless networks. Wireless networks must cope with dynamic link conditions not present in wired infrastructures, which place a heavy burden on quality of service management solutions. Managing QoS in the face of constantly changing operating conditions demands dynamic management approaches that span multiple layers in the protocol stack. Such as cross-layer design approaches have recently received attention in the context of cellular and mobile special networks. This article introduce the notion of network predictability and describe its relationship to achievable QoS. This relationship is used to propose a framework for cross layer design that can be used to guide development efforts and direct investment decisions for future networks.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.127-134
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• 2011

Recently, the wireless data communication infrastructure appearing before the footlights crosses the limit in the wire and develop into the fast speed. Particularly, the issue about the u-Healthcare service using this increases. And the investigation of the quality guarantee of the wireless data network is important for the smooth service providing. However, the quality control research about the wireless network is insufficient because the existing research performs the quality control between the termination about the wired network continually. This paper presented the mobile service quality measurement reference considering the radio environment,that is the method for satisfying the quality guarantee of the wireless data network user offered the u-Healthcare service as the research about this and user needs. For this purpose, wireless data quality measurement indicator and standard was selected. The quality measure evaluation plan was presented according to the service. And each service presented the quality index especially.

• Journal of Advanced Navigation Technology
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• v.12 no.4
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• pp.350-356
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• 2008

The recent networks are trending toward wireless networks. So wireless internet used to service of wired networks. But wireless networks can't show same performance of wired networks. Therefore, we are must concerned about Routing Protocol for improvement of a weak point of physical feature. But many researchers are not focusing on developing Routing Protocol. In this paper, we improve on AODV(Ad-hoc On-demand Distance Vector) for Wireless Mesh Networks. And it analyzed the result of simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.7
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• pp.467-476
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• 2014

Recently, various services which use the fused form of broadcasting and communication are being offered over the Internet globally. To provide various interactive services through connected smart TV on wired or wireless network, the seamless multimedia service is key feature. In this paper, Dynamic Adaptive Streaming over HTTP (DASH)is adopted to develop cost-effective adaptive streaming system for Open Hybrid TV(OHTV) service. This system can provide seamless adaptive streaming service for IP VOD, Video Clips, Ad insertion which are defined in OHTV.

• Journal of The Korean Association of Information Education
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• v.9 no.3
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• pp.533-548
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• 2005

According to the increasing of the internet infrastructure and growth of contents technology, the users can access an education service at anytime and anywhere. In a field of English education, especially, internet technology has enabled learners to communicate with their teachers and multimedia contents technology has been able to provide learner not only lots of interests, but also good effect on English learning. In this paper, we propose a method diagnosing learner's level by using some question-items, which consist of item's type and item's function. Futhermore, the proposed system can support three devices which are PC, PDA, and Mobile Phone on wired and wireless internet communication environments. Also, the system provides multimedia contents including flash movies, image, and audio contents. We have applied the system into real classroom, and we verified that the question-items that system provides has no problem, and our method could improve each learner skill on English education. Therefore, we expect that learner who uses the proposed system will get level-based English learning service at anytime and anywhere.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.1B
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• pp.7-16
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• 2005

Resource Reservation Protocol(RSVP) can provide Quality-of-Service(QoS) guarantees for real-time services in wired networks. However, RSVP suffers from mobility problem in the mobile Internet. Therefore, to provide seamless QoS services, it is needed that a mobile node makes a reservation everywhere it visits. Recently, many protocols have been proposed to provide QoS guarantees through advance resource reservation. But, these proposals have problems with a waste of bandwidth and the signaling overhead due to advance resource reservation. In this paper, we propose new advance resevation protocol, Proportional Aggregate RSVP(PA-RSVP) to minimize the resource reservation bandwidth and the signaling overhead in the mobile Intemet while providing QoS guarantees. Based on the performance evaluation, we show that the proposed protocol provides an improved performance over existing protocols under various system conditions.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.648-653
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• 2008

With development of mobile communications terminal and expansion of mobile Internet, a large number of users can use mobile web contents at anytime and anywhere and will demand service of greater contents. Due to such demand, many studies are being carried out on transcoding contents so that wired web contents can be used in mobile web. However, transcoding and creation of mobile web contents involve difficulties because specifications available from telecommunications companies and mobile terminals have not been standardized. Especially, in order for serving dynamic object of wired web page contents to dynamically change according to time or user, it is required not only to program scripts to suit each terminal, but also to transcode the resources used in advance. For solution to this problem, this study uses the hierarchy structure of DOM (document object model) to display structural characteristics of wired web page. In other words, this study proposes the following technique Wired web pages are analyzed and the results are established as data structure. Then, dynamic object is extracted and the domain is indexed so that, when serving mobile web page, information can be extracted at the indexed position to create mobile web contents for service on real-time basis.