• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.35-40
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• 2019

It is important to constantly provide service in real-time multimedia applications using multicast. Transmission path reconstruction occurs in hybrid multicast using Internet Protocol (IP) multicast and ALM in order to adapt the network status to things like congestion. So, there is a problem in which real-time QoS is reduced, caused by an increase in end-to-end delay. In this paper, we want to solve this problem through multi-layer transmission path construction. In the proposed method, we deploy the control server and application layer overlay host (ALOH) in each multicast domain (MD) for hybrid multicast construction. After the control server receives the control information from an ALOH that joins the MD, it makes a group based on the hop count and sends it to the ALOH in each MD. The ALOH in the MD performs the role of sending the packet to another ALOH and constructs the multi-layered transmission path in order of priority by using control information that is received from the control server and based on the delay between neighboring ALOHs. When congestion occurs in, or is absent from, the ALOH in the upper MD, the ALOH selects the path with the highest priority in order to reduce end-to-end delay. Simulation results show that the proposed method could reduce the end-to-end delay to less than 289 ms, on average, under congestion status.

• Journal of Broadcast Engineering
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• v.17 no.4
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• pp.640-658
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• 2012

One of the existing terrestrial multi-channel DTV service frameworks, called KoreaView, provides four programs, composed of MPEG-2 based one HD video and H.264/AVC based three SD videos within one single 6MHz frequency bandwidth. However the additional 3 SD videos can not provide enough quality due to its reduced spatial resolution and low target bitrates. In this paper, we propose a framework, which is called a terrestrial multi-channel high quality hybrid DTV service, to overcome such a weakness of KoreaView services. In the proposed framework, the three additional SD videos are encoded based on an H.264/SVC Spatial Base layer, which is compliant with H.264/AVC, and are delivered via broadcasting networks. On the other hand, and the corresponding three additional HD videos are encoded based on an H.264/SVC Spatial Enhancement layer, which are transmitted over broadband networks such as Internet, thus allowing the three additional videos for users with better quality of experience. In order to verify the effectiveness of the proposed framework, various experimental results are provided for real video contents being used for DTV services. First, the experimental results show that, when the SD sequences are encoded by the H.264/SVC Spatial Base layer at a target bitrate of 1.5Mbps, the resulting PSNR values are ranged from 34.5dB to 42.9dB, which is a sufficient level of service quality. Also it is noted that 690kbps-8,200kbps are needed for the HD test sequences when they are encoded in the H.264/SVC Spatial Enhancement layer at similar PSNR values for the same HD sequences encoded by MPEG-2 at a target bitrate of 12 Mbps.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.11
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• pp.1004-1013
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• 2012

The legacy voice broadcast systems are used to broadcast the voice over an entire space or a specific zone. these broadcast systems generate unnecessary noise and waste of resources. In this paper, we propose a ubiquitous voice message broadcast system called uPaging, by combining the technique of location-awareness and the voice message delivery service in ubiquitous sensor network environment. In uPaging system, the wire/wireless hybrid network is used to implement the network system. Also, in order to actualize the location-awareness service, we use the Bidirectional Location ID-Exchange protocol was suggested by our previous research. the uPaging system can deliver the voice to a selected user or the location in which the user is present by this location awareness.

• Spatial Information Research
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• v.17 no.2
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• pp.171-181
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• 2009

In Web2.0 environment, with advanced platform technologies, global vendors such as Google, Microsoft and Yahoo provide competitive geospatial services based on global map and satellite image. But the relatively low level of platform technologies has not rapidly increased the land information and geospatial service markets in Korea. For the ubiquitous next generation Internet, as a one of the R&D projects by Korean Land Spatialization Group, the project for platform technologies has being made to provide customized land information and geospatial service. The platform technologies can be categorized for streamming, mashup and geosearch. More specifically, the 2D/3D Hybird streamming engine, mashup engine for u-GIS service and next generation search engine for land information have being developed. In this context, the strategies for efficient development and use of geoweb platform technologies are required. This study surveys the present geospatial products and services using of platform technologies to propose the strategies for efficient development and use of platform technologies. The strategies for efficient development and use of platform technologies can be proposed focusing on target market and each of platform technologies.

• Journal of KIISE
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• v.45 no.3
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• pp.211-223
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• 2018

In this paper, we propose a robot-centered direction relation representation and the relevant reasoning methods for indoor service robots. Many conventional works on qualitative spatial reasoning, when deciding the relative direction relation of the target object, are based on the use of position information only. These reasoning methods may infer an incorrect direction relation of the target object relative to the robot, since they do not take into consideration the heading direction of the robot itself as the base object. In this paper, we present a robot-centered direction relation representation and the reasoning methods. When deciding the relative directional relationship of target objects based on the robot in an indoor environment, the proposed methods make use of the orientation information as well as the position information of the robot. The robot-centered reasoning methods are implemented by extending the existing cone-based, matrix-based, and hybrid methods which utilized only the position information of two objects. In various experiments with both the physical Turtlebot and the simulated one, the proposed representation and reasoning methods displayed their high performance and applicability.

• Journal of Digital Convergence
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• v.13 no.7
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• pp.333-340
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• 2015

Mileage system in some online media, I have a lot of use. In addition, there are a lot of companies that are making money by using the mileage system. A mileage system is the first airline in such a way that the service in the late 1980s, many states now listed sungineung and features. In addition, there are many industries that reported good results using a mileage system used by carriers in other industries. However, mileage of the current game industry has not been introduced, it is not the service by using the concept of point returning to the user is purely a function of mileage. So a lot of developed payment systems in the mobile industry since 2010, proposed a better and more current online payment systems industry has an easy hybrid revenue model for mobile games service convergence mileage using this system.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.1
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• pp.39-46
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• 2012

We can adapt telemedicine systems in advancement of information technology capabilities and increase of network bandwidth. The telemedicine service can be applied to a public health center, a school, a prison and islands in lacks of medical equipments and medical staffs. The telemedicine services which can be provided high quality medical services. We designed the multiple control server system consisting 3 sub-function, patients and doctors name list, network types, connection states and computer equipments. The telemedicine link configuration was decided as 'Flowing', or 'By-passing' in accordance the network type and bandwidth of patient systems or doctor systems. The multiple control server system was performed the best communication configuration over heterogeneous networks. This system was achieved high quality telemedicine services through dynamic wired and wireless networks at any time. This study represented a hybrid multimedia telemedicine system over heterogeneous networks. We expected that the designed system could provide not only the high quality services, tele-diagnosis and tele-consultation, but also the effective emergency telemedicine services to multi-patients in the heterogeneous network environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.12
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• pp.2811-2817
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• 2010

In this paper we propose the QAC-MAC that supports Quality of Service(QoS) and saves energy resources of the sensor node, and hence prolonging the lifetime of the sensor network with multiple sink nodes. Generally, the nodes nearest to the sink node often experience heavy congestion since all data is forwarded toward the sink through those nodes. So this critically effects on the delay-constraint data traffics. QAC-MAC uses a hybrid mechanism that adapts scheduled scheme for medium access and scheduling and unscheduled scheme based on TDMA for no data collision transmission. Generally speaking, characteristics of the real-time traffic with higher priority tends to be bursty and has same destination. QAC-MAC adapts cross-layer concept to rearrange the data transmission order in each sensor node's queue, saves energy consumption by allowing few nodes in data transmission, and prolongs the network lifetime.

• Journal of the Korean Society for Railway
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• v.18 no.5
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• pp.471-480
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• 2015

Reliance on road transport in domestic logistics can lead to intensified congestion and greenhouse gas emissions due to the rise in oil prices, any increase in logistics costs can have a high social cost. The government policy on Low Carbon Green Growth is seeking to take advantage of the railway system. However, existing railway transport logistics systems, for reasons such as low speed, low track capacity constraints, and the impossibility of implementing a Door to Door system, make it difficult to activate a railway logistics program. As a result of this study, a national R&D project to develop a High-Speed Passenger/Baggage Mixed Train(Hy-SoBex) utilizing the rail capacity constraints to overcome the difficulties of linking an air cargo and freight railway logistics system, we propose a variety of service models and select the optimal service model.

• Electronics and Telecommunications Trends
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• v.31 no.3
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• pp.81-90
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• 2016

현재, 극장 사운드를 중심으로 객체기반 오디오 기술을 포함하는 하이브리드 포맷의 사운드 서비스가 점차 확산되고 있으며, 미국, 유럽, 한국 등에서는 차세대 방송용 오디오에 객체기반 오디오 기술의 도입을 적극적으로 고려하고 있다. 객체기반 오디오 기술은 콘텐츠의 제작단계에서 재생환경을 고려할 필요가 없고, 현장의 음향을 신호와 3차원 공간정보로 구분하여 음향공간의 정보를 그대로 표현함으로써, 재생단말에서 3차원 공간정보를 활용하여 재생할 수 있게 한다. 이러한 객체기반 실감음향 기술개발을 위해서는 편리한 제작 및 3차원 공간정보 표현 기술이 필요하며, 청취환경에서는 객체기반 실감음향 콘텐츠를 제작자의 의도대로 렌더링할 수 있는 재생 및 제어 기술이 필요하다. 이에 객체기반 실감음향 기술이 포함되는 하이브리드 오디오 기술의 현황에 대하여 살펴보고자 한다.