• Journal of Multimedia Information System
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• v.1 no.2
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• pp.127-132
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• 2014

The transverse electromagnetic (TEM) cells are widely used for electromagnetic compatibility (EMC) testing and field probe calibrations. We propose the verification of TEM mode with statistical method using a four-port TEM cell. The verification results are compared with Normal, Rayleigh, and Gamma distribution. As a result, the 75 % quantile of the Rayleigh distribution is excellent agreement with the true quantiles for a number of calibration points.

• ETRI Journal
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• v.28 no.4
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• pp.506-508
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• 2006

A frequency selective surface (FSS), whose unit cell consists of a ternary tree loop loaded with a modified tripole, is proposed to block multiple frequency bands. Target frequency bands correspond to Korean personal communication services, cellular mobile communication, and 2.4 GHz industrial, scientific, and medical bands. Through the adjustment of inter-element and inter-unit cell gaps, and adjustment of the length of elements, we present an FSS design method that makes the precise tuning of multiple resonance frequencies possible. Additionally, to verify the validity of our approach, simulation results obtained from a commercial software tool and experimental data are also presented.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.5
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• pp.139-145
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• 2010

In this paper, we propose robust cell ID detection algorithm and SNR estimation algorithm applicable to mobile base station, which can be operated independently. The proposed cell ID estimation uses signal subspace to estimate cell IDs used in cell. The proposed SNR estimation algorithm uses number of noise subspace vectors and the corresponding eigen-vectors. Through the computer simulations, we showed that performance of the proposed cell ID detection and SNR estimation algorithms are superior to existing correlation based algorithms. Also we showed that the proposed algorithm is suitable to fast moving channel in high background noise and strong interference signal.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.7
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• pp.1256-1262
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• 2008

In mobile broadcasting networks, handover is an important issue to support seamless mobility. DVB-H(Digital Video Broadcasting for Handheld) standard was developed to enhance mobile features for DVB-T(Digital Video Broadcasting -Terrestrial) standard. This paper proposes new approaches for improving handover performance in the DVB-H networks. The proposed handover schemes are targeted to two different DVB-H receivers: One is for the receivers equipped with GPS devices. The other is for ones without GPS support. The first handover approach modifies the cell description table (CDT) proposed in the literature [1]. The second proposes a novel estimation technique of predefined handover region based on a new handover map table (HMT). This new handover approach estimates a predefined handover region with the measured RSSI(Received Signal Strength Indication) signal patterns. Using proposed handover algorithm, we can reduce time and power consumption. Through the computer simulations, we evaluate the performance of handover algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.8
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• pp.1574-1581
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• 2007

DVB-H (Digital Video Broadcasting for Handhold) is a new standard, currently being developed for a portable digital broadcasting, which enhance the multimedia broadcasting service in the Euroapean standard DVB-T (DVB-Terrestrial). Seamless mobility and power saving are essential requirements in the DVB-H system. To support seamless mobility, DVB-H system should provides seamless handover for mobile stations in the MFN (multi frequency network). For seamless handover, the receiver should monitor neighboring cells and it increases the power consumption. And so, power efficient sell searching algorithm for seamless handover is required. In this paper, we propose hypothesis feeling based handover algorithm to enhance the power efficiency by using the fast cell searching, and analyze the performance of handover schemes through the numerical evaluation and simulation.

• Journal of Broadcast Engineering
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• v.27 no.5
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• pp.762-772
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• 2022

Current disaster alert broadcasting based on mobile communication systems targets personal mobile terminals such as smartphones. However, smart cities require IoT-based services such as smart homes and offices. Therefore, when severe disasters such as earthquakes occur, smart cities must quickly perform appropriate control and respond to buildings and factories. For this, a disaster warning broadcasting technique for IoT terminals for smart cities is required. In this paper, we propose a disaster alert transmission method based on 4G/5G mobile communication for IoT terminals for smart cities. The proposed method effectively utilizes the image display method for CBS, a cell-based broadcasting service, and shows the superiority of the proposed approach through simulation.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.104-120
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• 2022

In severe disaster situations, Emergency alert provide information for people to survive. However, the only device that can receive the Cell Broadcasting Service (CBS) of the Korean Public Alert System (KPAS), the Public Warning System (PWS), is Smart Phone and Receiving the disaster information is very limited. Therefore, this paper proposes a solution to the problem. First, we discover problems through the analysis of KPAS, and second, we propose Smart Watch and Navigation as devices to receive Emergency alert. The devices can receive disaster information through Bluetooth communication from Smart Phone and provide content such as disaster-related images and videos. Based on the proposed items, the application was developed, and as a result of the test, Smart Phone provided more disaster information like images and videos than current emergency alert, and the method of notification of emergency alert was varied. And Smart Watch and Navigation received disaster information successfully through Smart Phone, which also provided various disaster information like images and videos. The developed application has expanded functionally than the existing emergency alert and can benefit many people in emergency situations.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.04a
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• pp.810-812
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• 2015

문자인식 즉 OCR(Optical Character Recognition)기술은 광학적으로 인식할 수 있는 문자를 컴퓨터가 읽을 수 있도록 하는 기술을 뜻한다. 문자인식의 근간이 되는 방법은 스트링 매칭 기법이 사용되어 왔지만 한글의 경우 자음, 모음, 자음 조합으로 만 가지 유형이 넘고, 더욱이 상용한자와 영어를 섞어 쓰기 때문에 오인식되는 경우가 많다. 본 논문에서는 한글이 수직선, 수평선, 사선과 같이 방향성이 강한 선소들로 구성되어 있다는 점을 이용하여 한글의 인식률을 높이는 방법을 제안하였다.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.3
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• pp.113-120
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• 2024

Recently, case presentations using AI functions such as ChatGPT are increasing in many industrial fields. As AI-based results emerge even in the areas of images and videos, traditional animation production tools are in need of significant changes. Unreal Engine is the tool that adapts most quickly to these changes, proposing a new animation production workflow by integrating tools such as Metahuman and Marvelous Designer. Working with realistic metahumans allows for the production of realistic and natural movements, such as those captured through motion capture data. Implementing this approach presents many challenges for production tools that adhere to traditional methods. In this study, we investigated the differences between the cell animation workflow and the computer graphics animation production workflow. We compared and analyzed whether these differences could be reduced by creating sample movements using character rigs in Maya and Cascadeur tools. Our results showed that a similar cell animation workflow could be constructed using the Cascadeur tool. To improve the accuracy of our conclusions, we created large, action-packed short animations to demonstrate and validate our findings.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.105-117
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• 2015

In this paper, we consider 19 cells with the two tiers for polar-rectangular coordinates (PRCs) and provide the cell edge performance of cellular networks based on distance from cell center i.e., BS (base station). When FFR is applied(or adopted) to cell edge, it is expected that BS cooperation, or a coordinated multipoint (CoMP) multiple access strategy will further improve the system performance. We proposed a new method to evaluate the sum rate capacity of the MIMO DC of multicell system. We improve the performance of cell edge users for intercell interference cancelation in cooperative downlink multicell systems. Simulation results show that the proposed scheme outperforms the reference schemes, in terms of cell edge SINR (signal-to-interference-noise ratio) with a minimal impact on the network path loss exponent. We show 13 dB improvements in cell-edge SINR by using reuse of three relative to reuse of one. BS cooperation has been proposed to mitigate the cell edge effect.