• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.487-488
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• 2009

지난 50년 동안 TV 방송은 우리의 문화와 생활에 중요한 영향력을 가져왔다. 시청자들의 더욱 많은 콘텐츠와 서비스에 대한 요구는 급증하였다. 이전 방송서비스는 지상파, 케이블, 위성, DMB를 통하여 제공되었다. 최근 IP망을 통한 IPTV는 새롭고 다양한 서비스가 제공될 것으로 기대되어 시청자들을 충족시킬 수 있을 것으로 기대된다. 대표적인 인터넷 방송의 특징인 양방향성은 기존의 방송들과의 차이점으로서 새로운 서비스 기술개발이 이루어지고 있다. 본 논문에서는 기존의 광고 서비스의 단점을 보완하여 인터넷 방송에서의 양방향성 이점을 이용한 개인별 맞춤형 타깃 광고 방송시스템을 설계 및 구현하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.4C
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• pp.417-425
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• 2006

This Paper Proposes a method of building a panoramic video from several videos captured from adjacent cameras. The panoramic image which constructed from adjacent and overlapped images is used for photogrammetry, satellite photo or many computer graphic applications. The perspective transformation, which is estimated from the appropriate corresponding pairs of images, can be used to construct the panoramic image without unwarranted distortion and its quality is decided by how to find the features needed for transform estimation. We used the corner points for the corresponding features, and morphological structures were utilized for fast and robust corner detection. We used the criterion of the corner strength, which guarantees the robust detection of the corner in most situations. For the transformation, 8 parameters were estimated from perspective equations which use matched points of adjacent images, and bilinear color blending was used to construct a soapless panoramic video. The experiments showed that the proposed method yields fast results with good quality under various conditions.

• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.80-85
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• 2015

In this paper, we present, an indstrial RFID layered microstrip patch antenna is designed using an inset feed method in order to improve recognition rates in a long distance as tags are attached to metal object by improving a problem of feeding power in fabricating metal tags and reducing effects of metallic object. The inset feed shows a distinctive characteristic that has no separation between emitters and feed lines differing from a structure with the conventional inductive coupling feed. This structure makes possible to produce a type that presents a low antenna height and enables impedance coupling for tag chips. Although it shows a difficulty in the impedance coupling due to increases in the parasite capacitance between a ground plane and an emitter in an antenna according to decreases in the height of a tag antenna, it may become a merit in designing the tag antenna because the antenna impedance can be determined as an inductive manner if a shorted structure is used for feeding power. Therefore, in this paper the microstrip patch antenna is designed as a modified type and applies the inset feed in order to reduce effects of metallic objects where the antenna is be attached. Also, the antenna uses a multi-layer structure that includes a metal plate between radiator and ground instead of using a single layer.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.9A
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• pp.924-933
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• 2008

This paper proposes a novel LDPC code decoder architecture to improve throughput for DVB-S2, a second generation standard of ETSI for satellite broad-band applications. The proposed architecture clusters 360 bitnodes and checknodes into groups utilizing the property of IRA-LDPC code. Functional modules which perform calculations for bitnode groups and checknode groups have local memories and store the messages from the other type of functional modules connected by edges at their local memories. The proposed architecture can avoid memory conflicts by accessing stored messages sequentially, hence, increases throughput in the proposed DVB-S2 LDPC code decoder architecture. The proposed architecture was synthesized using the TSMC 90nm technology. Synthesis results show that throughput of the proposed architecture is improved by 104% and 478%, respectively, when compared with those of the architectures proposed by F. Kienle and J. Dielissen.

• Aerospace Engineering and Technology
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• v.12 no.1
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• pp.120-127
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• 2013

Recently, In Aerospace area the interest of open source software is increasing. One of examples is celestia that is used for visualizing space environment with 3D. Celestia that is open source software has many advantages. First is very easy to use, second is that it can extend new features easily with script language. It is very useful to extend with other systems. But, celestia has a few of remote control features from remote site. In this paper I describe design and implementation of remote control module using UDP communication protocol between celestia and GenSim that is satellite simulation software developed by KARI and describe the problem and solution items are found during development duration.

• Journal of Aerospace System Engineering
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• v.17 no.4
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• pp.1-9
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• 2023

Recently, as Synthetic Aperture Radar (SAR), communication, and signal surveillance missions of spacecraft have become more advanced, research has been actively conducted on the deployable large mesh antenna system with excellent storage efficiency compared to the deployment area, and light weight. Deployable Mesh antennae are characterized by an increase in the number of Openings Per Inch (OPI), which is a measure of mesh weaving density as the mission frequency band increases, and this OPI change directly affects the thermal optical properties of the mesh antenna, so research on this is required. In this paper, to verify the thermal relationship between the optical properties of the mesh and antenna reflector, thermal sensitivity analysis between the mesh and the antenna reflector is performed by in-orbit thermal analysis with various optical characteristics of the mesh based on existing overseas research cases. In addition, the temperature gradient effect of the mesh reflector is analyzed.

• Journal of Satellite, Information and Communications
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• v.6 no.1
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• pp.86-96
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• 2011

In this paper we propose a Pre-rake system applied with a frequency domain equalizer in TDD/CDMA multi-code transmission. The Pre-rake system has been well known technique in TDD/CDMA to make a receiver simple. However, it still has residual losses of path diversity and signal to noise ratio (SNR). However, gathering all the residual paths demands an additional hardware such as a rake combiner at the receiver. For the reason Pre/Post-rake system has already been proposed at up/downlink correlated channel conditionunder the assumption of noisier channel. There is a trade-off between the first purpose of Pre-rake that makes hardware simple at the receiver and the performance improvement. From the point the frequency domain equalizer (FDE) can be considered in Pre/Post-rake to supply the receiver with the flexible equalizing methods with rather reduced complexity compared with time domain rake combiner or equalizers. Pre-rake itself increases the number of multipath, which results from the convolution of Pre-rake filter and wireless channel, and FDE must be well matched to Pre/Post-rake, while it considers the relationship of hardware complexity and the performance. In this paper, the Pre-rake/Post-FDE system is introduced at TDD/CDMA multi-code transmission. In addition, the cyclic prefix reduction method in the proposed system is introduced, and the theoretical analysis to the proposed system is given by assuming Gaussian approximation, and finally the numerical simulation results are provided.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.4
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• pp.45-54
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• 2012

Location-based services with GPS positioning technology as a key technology, but recognizing the current location through satellite communication is not possible in an indoor location-aware technology, low-power short-range communication is primarily made of the study. Especially, as Chirp Spread Spectrum(CSS) based location-aware approach for low-power physical layer IEEE802.15.4a is selected as a standard, Ranging distance estimation techniques and data transfer speed enhancements have been more developed. It is known that the distance measured by CSS ranging has quite a lot of noise as well as its bias. However, the noise problem can be adjusted by modeling the non-zero mean noise value by a scaling factor which corresponds to the change of magnitude of a measured distance vector. In this paper, we propose a localization system using the CSS signal to measure distance for a mobile node taken a measurement of the exact coordinates. By applying the extended kalman filter and least mean squares method, the localization system is faster, more stable. Finally, we evaluate the reliability and accuracy of the proposed algorithm's performance by the experiment for the realization of localization system.

• The Journal of the Korea Contents Association
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• v.14 no.8
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• pp.342-364
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• 2014

The purpose of this paper is to provide an answer for the following question: What are the major shifts and implications of the unprecedently competitive and rapidly changing media ecosystem in the era of N-screen and OTT services? I've attempted to understand the complex and competitive nexus among media from an historical context by focusing on the displacement vs. complement thesis. The TPC model by Han has been employed for the analysis of the current dynamics of US media industries by triangulating three areas: Technology/industry, public policy and consumer/culture. More specifically, the US media landscape is initially divided into two competitive turfs - the competitors equipped with OTT services and the legacy media industry, and then the traditional media industry was grouped again into PayTV group(telecom service providers with IPTV and mobile TV, cable/Satellite TV networks) and Free (over-the-air) TV networks. Six major shifts were identified by the analysis: power shift in telecom carriers, power shifts in TV industry, Telecom/OTT partnership, time shifts, place shifts, and finally business model shifts.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.1-6
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• 2020

UAV (Unmanned Aerial Vehicles) are used widely for military purposes because they are more economical than general manned aircraft and satellites, and have easy access to the object. Recently, owing to the development of IT technology, UAV equipped with various sensors have been released, and their use is increasing in a wide range of fields, such as surveying, agriculture, meteorological observation, communication, broadcasting, and sports. An increasing number of studies and attempts have made use of it. On the other hand, existing research was related mostly to photogrammetry, but there has been a lack of analytical research on LiDAR (Light Detection And Ranging). Therefore, this study examined the characteristics of a UAV LiDAR sensor for the application of a geospatial information field. In this study, the performance of commercialized LiDAR sensors, such as the acquisition speed and the number of echoes, was investigated, and data acquisition and analysis were conducted by selecting Surveyor Ultra and VX15 models with similar accuracy and data acquisition distances. As a result, a DSM of each study site was generated for each sensor, and the characteristics of data density, precision, and acquisition of ground data from vegetation areas were presented through comparison. In addition, the UAV LiDAR sensor showed an accuracy of 0.03m ~ 0.05m. Hence, it is necessary to select equipment considering the characteristics of data for effective use. In the future, the use of UAV LiDAR may be suggested if additional data can be obtained and analyzed for various areas, such as urban areas and forest areas.