• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.7
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• pp.1213-1223
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• 1994

VSATs(Very Small Aperture Terminals) have introduced new concepts in satellite business communications and are typically used in a star network configuration to provide information directly to the user`s premise. The characteristics of this system are low earth station costs, easy in stallation, compact, and very high flexibility for a varierty of applications (Credit Checks, Electronic Mail, Video Conferencing, Reservation System, Database Inquires, Order Entry, etc.). So, the requests of VSAT service have considerably enlarged. The link design of a VSAT network using Korea Sat. is discussed in this paper. This paper is intended to collect in a convient way the principle formula and reference data necessary to make overall performance calcurations and to calcurate antenna size. HPA power size and link margin of earth stations for satellite communications systems. Generally, because the antenna size of the Hub station in the VSAT system is bigger than the Remote station, the method of power allocations of inbound and outbound carriers is utilized in this paper. The size of Hub station and Remote station are assumed to be 3.7m and 1.2m. respectively.

• Journal of Korea Game Society
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• v.14 no.5
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• pp.117-126
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• 2014

There are various kinds of applications if one can develop a remote execution system using for legacy 3D APIs. It can be used in implementing a cloud gaming service based on the real-time video streaming technology. Or, it can also be used in implementing a GPU virtualization for simultaneously rendering of many different 3D applications. The OpenGL API consists of independent global functions while the Direct3D API consists of Microsoft COM-based interfaces and their member functions, which makes the implementation of remote rendering system more difficult. The purpose of the paper is to show the applicability of the technology to any legacy 3D API by successfully designing and implementing a remote rendering system using the Direct3D API. It applies the implementation to a sample Direct3D application and also performs a few experimentations to show the technical feasibility.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.751-757
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• 2021

In this paper, we proposed a pipeline system for holographic image production in a web server-based environment. There are time and spatial constraints for the existing holographic image production. The purpose of the proposed system is to obtain high-quality holographic images by reducing accessibility to users. It is a structure in which a video captured by a user in a web environment is transmitted to a server and converted into a frame for holographic image production through post-production. For high-quality holographic image acquisition, post-processing uses a deep learning-based algorithm. The proposed system provides various service tools in the web environment for user convenience. Through this method, the user's accessibility is improved when producing holographic images because images are taken in a web environment rather than in a limited space.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.3 no.6
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• pp.575-596
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• 2009

Facing limited network resources such as bandwidth and processing capability, the Internet will have congestion from time to time. In this paper, we propose a scheme to maximize the total utility offered by the network to the end user during congested times. We believe the only way to achieve our goal is to make the scheme application-aware, that is, to take advantage of the characteristics of the application. To make our scheme scalable, it is designed to be class-based. Traffic from applications with similar characteristics is classified into the same class. We adopted the RED queue management mechanism to adaptively control the traffic belonging to the same class. To achieve the optimal utility, the traffic belonging to different classes should be controlled differently. By adjusting link bandwidth assignments of different classes, the scheme can achieve the goal and adapt to the changes of dynamical incoming traffic. We use the control theoretical approach to analyze our scheme. In this paper, we focus on optimizing the control on two types of traffic flows: TCP and Simple UDP (SUDP, modeling audio or video applications based on UDP). We derive the differential equations to model the dynamics of SUDP traffic flows and drive stability conditions for the system with both SUDP and TCP traffic flows. In our study, we also find analytical results on the TCP traffic stable point are not accurate, so we derived new formulas on the TCP traffic stable point. We verified the proposed scheme with extensive NS2 simulations.

• ETRI Journal
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• v.32 no.6
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• pp.854-862
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• 2010

One-way delay variation (OWDV) has become increasingly of interest to researchers as a way to evaluate network state and service quality, especially for real-time and streaming services such as voice-over-Internet-protocol (VoIP) and video. Many schemes for OWDV measurement require clock synchronization through the global-positioning system (GPS) or network time protocol. In clock-synchronized approaches, the accuracy of OWDV measurement depends on the accuracy of the clock synchronization. GPS provides highly accurate clock synchronization. However, the deployment of GPS on legacy network equipment might be slow and costly. This paper proposes a method for measuring OWDV that dispenses with clock synchronization. The clock synchronization problem is mainly caused by clock skew. The proposed approach is based on the measurement of inter-packet delay and accumulated OWDV. This paper shows the performance of the proposed scheme via simulations and through experiments in a VoIP network. The presented simulation and measurement results indicate that clock skew can be efficiently measured and removed and that OWDV can be measured without requiring clock synchronization.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.1
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• pp.69-75
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• 2020

This paper introduces the parking guide service developed to address the inconvenience of parking in areas where demand for parking spaces is high, such as busy streets and tourist attractions. Due to difficulties in measuring and developing the actual parking lot while driving the car, we created a temporary parking lot and created Arduino RC Car to replace the actual car. Video processing based on Open CV allows users to identify the entire parking lot, parking space, and completed parking space, and track moving cars, and this information has been developed to enable users to see through the application. The application allows the user to book the desired parking space and introduce a way-finding algorithm to guide them through the optimal path to the selected parking compartment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.1
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• pp.192-196
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• 2010

Due to a development of a modem technology as Power Line Communication(PLC) over 200 Mbps, the high-speed multi-media data trasmission could be currently possible. The strength of the PLC has no more additional wiring work. PLC has also possible to high quality data transmission with currently electrical cable. It has a various strong point campare with existing wire and wireless communication technologies. In This paper we develop a high quality media transmitter-receiver based on merging the HomePlug AV, which is 200 Mbps class PLC technology and HDMI Interface technology. The video function was used for the VEDEO TEST GENERATOR in order to a property valuation. Smart Live 6 software were used for the assessment of audio property. As the result of measurement of the HD class images by capturing from the receiver of the PLC, the quality of images couldn't be confirm any deterioration, which has compared with original reflections. In case of audio part as the result of confirmation of the Phase, Magnitude, it has been confirmed that over 90% of nomal transmition and receiving of acoustic signal. It can be possible to have HD class Media service through the PLC.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.142-146
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• 2007

Digital Rights Management (DRM) technology has been widely used for protecting the digital contents over the recent years. But the digital contents protected by DRM are vulnerable to various video memory capture programs when DRM packaged contents are decrypted on the consumers' multimedia devices. To make up for this kind of DRM security holes the Forensic Marking (FM) technology is being deployed into the content protection area. Most leading DRM companies as well as big electronics companies like Thomson and Philips already have commercial FM solutions. Forensic Marking technology uses the digital watermarking to insert the user information such as user id, content playing time and etc. into the decrypted and decoded content at the playback time on the consumer devices. When the content containing watermarked user information (Forensic Mark) is illegally captured and distributed over the Internet, the FM detection system takes out the inserted FM from the illegal contents and informs contents service providers of the illegal hacker's information. In this paper the requirements and test conditions are discussed for the commercial Forensic Marking systems.

• The Transactions of the Korea Information Processing Society
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• v.6 no.1
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• pp.203-215
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• 1999

Recently with the rapid development of data communication products and service industry, the system on behalf of users for multimedia services such as VoD(Video on Demand), Teleshopping are at the height of development, However, if the new style products and services do not conform to the international standard, the products will come to lose the competitive power in the market. Therefore, it is essential to have conformance testing considered the properties of related protocol for the interoperability of the products and services. As a systematic and efficient conformance testing method of new products in respect of the main protocol of DAVIC(Digital Audio Visual Council) standard, this paper presents the protocol test methodology and architecture ; a single protocol stack an the related protocol stacks testing.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.2
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• pp.419-426
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• 2018

Ecotourism refers to tourism that senses and observes superior natural resources, cultural resources and history around. Today, as the current leisure patterns of the people change, a healing trip to find nature is being activated. In this paper, we propose a platform design and construction for providing ecotourism information. In the proposed platform, first, the image file of the eco-tourism objects taken every day from the image capture device is collected, converted into a video, uploaded to the server, then, when the tourist arrives at the eco-tourism object, It is designed to be able to watch.