• Smart Media Journal
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• v.13 no.4
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• pp.33-48
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• 2024

With the advent of 5G, characterized by Enhanced Mobile Broadband (eMBB), Ultra-Reliable Low Latency Communications (URLLC), and Massive Machine Type Communications (mMTC), efficient network management and service provision are becoming increasingly critical. This paper proposes a novel approach to address key challenges of 5G networks, namely ultra-high speed, ultra-low latency, and ultra-reliability, while dynamically optimizing network slicing and resource allocation using machine learning (ML) and deep learning (DL) techniques. The proposed methodology utilizes prediction models for network traffic and resource allocation, and employs Federated Learning (FL) techniques to simultaneously optimize network bandwidth, latency, and enhance privacy and security. Specifically, this paper extensively covers the implementation methods of various algorithms and models such as Random Forest and LSTM, thereby presenting methodologies for the automation and intelligence of 5G network operations. Finally, the performance enhancement effects achievable by applying ML and DL to 5G networks are validated through performance evaluation and analysis, and solutions for network slicing and resource management optimization are proposed for various industrial applications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.2
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• pp.213-219
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• 2012

Recently, we are simultaneously exposed by various electromagnetic sources due to an increase of mobile communication services. However, EMF(Electric, Magnetic and Electromagnetic Field) study has been performed mainly about only single frequency. The objective of this paper is to develop an multiple-frequency exposure system for in vitro experiment. The exposure unit for in vitro experiments was designed by radial transmission line type to get broadband characteristics to generate signals of CDMA at 836.5 MHz and WCDMA at 1950 MHz frequency simultaneously. The modulated signals were delivered to the conical antenna through amplifier, digital attenuator and RF combiner. SAR values were obtained by the averaged values of 3 measured values at 9 points in petri dish using the fiber optic temperature probe. The measured return loss was under -15 dB. For 1 W input power, the mean value and standard deviation of SAR were $0.105{\pm}0.019$ for the CDMA frequency and $0.262{\pm}0.055$ for the WCDMA frequency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.2 s.105
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• pp.89-94
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• 2006

A compact microstrip band-selective filter for ultra-wideband(UWB) radio system is proposed. The filter combines the traditional short-circuited stub highpass filter and coupled resonator band-stop filter on both sides of the mitered 50-ohm microstrip line. To realize the pseudo-highpass filtering characteristic over UWB frequency band(3.1 GHz to 10.6 GHz), a distributed highpass filter scheme is adopted. Three coupled resonators are utilized to obtain the band stop function at the desired frequency band. By meandering the coupled resonators, there is $29\;\%$ size reduction in footprint compared to the traditional band-stop filter using L-shaped resonators. The measured results show that the filter has a wide passband of $146.7\;\%$(2.1 GHz to 10.15 GHz) with low insertion loss and the stop band of $10.04\;\%$(5.2 GHz to 5.75 GHz) for 3-dB bandwidth. The measured group delay is less than 0.7 ns within the passband except the rejection band.

• Korean Security Journal
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• no.10
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• pp.323-354
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• 2005

As with the vast array of computer technology and its rapid development, along with the entry of the internet as one of the necessities of life, the so-called cyber space has become a vital component of our modern day living. While such cyber space has provided the society with much convenience and utility as to the gathering and acquiring of information, crimes involving cyber space has accordingly increased in both number and form, Nevertheless, the conventional law as existed before the development of the cyber space were unable to meet the demands of this new breed of crime, which inevitably led to the gap in the government ability to punish such criminals, Thus, in response to the rising number of cyber crimes, a large number of nations have either created or is in the process of committing human and financial resources to strengthen the investigative powers relating to cyber crimes and creating a new area of prohibiting such crimes. As a overview of cyber crime, (1)defines the terms, describes features of cyber crime, (2)explains the international prevention necessity of cyber crime, and (3)the necessity of legislating the cyber crime Fundamental Act (4)the recognition of the evidential values on the confiscated electronic records and reviews types of cyber crime including cyberterror. Lastly, emphasizes necessity on international cooperation for prevention of cyber crime as usual.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.10
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• pp.709-721
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• 2006

The traditional broadcasting services over terrestrial, satellite and cable media have been unidirectional mass media regardless of TV viewer's preferences. Recently ich media streaming has become possible via the broadb and networks. Furthermore, since bidirectional communication is possible, personalcasting such as personalized streaming services has been emerging by taking into account the user's preference on content genres, viewing times and actors/actresses etc. Accordingly, personal media becomes an important means for content provision service in addition to the traditional broadcasting service as mass media. In this paper, we introduce a user profile reasoning method for target advertisement which is considered an important application in personalcasting service. The proposed user profile reasoning method predicts an unknown TV viewer's gender and ages by analyzing TV Viewing history data. Based on the estimated user's gender and ages, a target advertisement is provided with TV Anytime metadata. A proposed target advertisement system is developed based on the user profile reasoning and the target advertisement selection method. To show the effectiveness of our proposed methods, we present a plenty of experimental results by using realistic TV viewing history data.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.11
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• pp.1275-1284
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• 2010

100 MHz bandwidth and 1 Gbit/s data speed are needed in LTE-advanced for the next generation mobile communication system. Therefore, spectrum aggregation method has been studied recently to extend usable frequency bands. Also bandwidth utilization is increased since vacant frequencies are used to communicate. However, transceiver structure requires the digital RF and SDR. Therefore, frequency synthesizer and PA must operate over wide-bandwidth and RF impairments also increases in transceiver. Uplink of LTE advanced uses DFT-S OFDM using plural power amplifier. The effect of ICI increases in frequency domain of receiver due to phase noise and IQ imbalance. In this paper, we analyze influences of ICI in frequency domain of receiver considering phase noise and IQ imbalance in multiband system. Also, we separate phase noise and IQ imbalance effect from channel response in frequency domain of uplink system. And we propose a method to estimate the channel exactly and to compensate IQ imbalance and phase noise. Simulation result shows that the proposed method achieves the 2 dB performance gain of BER=$10^{-4}$.

• Proceedings of the Korean Society of Community Living Science Conference
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• 2009.09a
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• pp.106-106
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• 2009

영국에서는 농촌문제의 심각성과 범정부적 대책 마련에 대한 부처간 인식 공유가 증가함에 따라 2000년 "농촌백서"에 '농촌서비스 표준화(Rural Services Standard, RSS)'를 제정하였다. RSS는 농촌 주민의 삶의 질 제고와 복지 서비스 향상을 위해 달성할 주요 서비스의 National Minimum을 의미한다. 매년 RSS 운용에 대한 지속적인 모니터링을 통하여 내용을 매년 업데이트 하고 있다. 교육 및 아동서비스, 광대역 통신, 사회적 돌봄, 우체국 서비스, 보건, 인터넷 접속, 긴급 서비스, 교통의 8개분야 13개 서비스 기준을 설정 제시하고 있다. 우리의 경우도 농촌 주민의 삶의 질 향상을 위한 범정부적 투자가 이루어져 왔지만 농촌지역의 사회서비스 기준을 도시와 비교해 보면 아직도 부족한 부분이 많이 있다. 농촌 인구가 감소되고 있는 상황에서 지속적인 하드웨어 중심적 투자에 대한 의문제기와 함께 농촌 주민들이 최소한의 공적 서비스를 활용할 수 있는 기반이 되어야한다는 의견이 대립되고 있는 가운데 그 해결책을 찾기 위하여 '농촌 서비스 기준'을 설정하자는 논의가 추진되고 있다. 이에 본 연구에서는 인구 5만 이상 군지역에 속하는 경상북도 울진군 기성면 척산리를 중심으로 농촌 정주지원 서비스 요구사항을 분석하였다. 척산리에는 총가구 187호 363명이 거주하고 있으며 지난 3년간 인구 이동이 전혀 없었다. 주민들의 연령대는 50~60대가 가장 많으며 척산 3리가 가장 고령화 되어 있는 것으로 나타났다. 교통 환경은 좋은 편이었는데 기성공용버스 정류장에 10곳 이상의 차편이 있고 7번 국도가 있어 타 지역으로 이동도 용이하였다. 마을에 보건/의료를 담당하는 곳은 보건진료소뿐이었으며 잦은 외근과 구급약 부족 등으로 불편을 호소하고 있었다. 응급상황 발생시 수송 가능한 응급체계는 갖춰져 있지 않았고 노인들이 가장 많이 이용하는 물리 치료실은 일주일에 3번 개방하기에 불편하다고 하였다. 3층 건물의 복지회관이 있으나 장날(5일장; 1일, 5일)만 개방되어 이용에 한계가 있었고 마을주민을 위해 운영되는 프로그램은 없었다. 논농사 중심의 경제생활이었고, 부녀회와 청년회 등은 면단위 또는 행정리로 묶어서 운영하고 있었다. 주민들은 울진군 면소재지 중 척산리에만 약국이 없어 불편한 사항이 많기에 약국, 물리치료실의 상시 개방을 필요로 하였으며 장날을 이용한 노인대상 영화상영, 강연회 등 다양한 문화프로그램 운영을 희망하였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.1 s.343
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• pp.111-120
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• 2006

In this paper, a node architecture of WDM metro network for connecting broadband access networks to converge wire/wireless networks. In consideration of the proposed node architecture and network requirements we proposed and evaluated medium access control protocols. We review WDM related technologies of sub-carrier multiplexing and optical components in order to resolve the bottleneck between optical backbone networks md access networks, and a access node architecture sharing common wavelength is introduced. Source-stripping (SS) MAC protocol Is evaluated under the proposed functional node architecture. DS+IS (Destination-Stripping and Source-Stripping) and DS+IS (Destination-Stripping and Intermediate-Stripping) MAC protocols are described to increase the slot-reuse factor which is low on SS MAC protocol. The key function of new MAC protocols regards the optical switch module of proposed node architecture and helps intermediate or source access nodes for dropping slots to destinations of different wavelength group. Thus, slot-reuse factor increases as the MAC protocols reduce the unnecessary ring-rotation of transferred slots. We use a numerical analysis to expect bandwidth efficiency and maximum throughput by slot-reuse factor Throughput network simulation, the verification of throughput, queuing delay, and transmission fairness are compared among MAC protocols.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.8
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• pp.745-753
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• 2011

In this paper, the planar monopole antenna for multi-band service is proposed. The proposed antenna, which is a rectangular patch antenna with a U-shaped slit based on a monopole antenna for wide bandwidth characteristic, is designed and analyzed. The antenna size has been miniaturized by using the U-shaped slit. The frequency characteristics are modified and optimized by varying specific parameters. To obtain desired frequency bands, the U-shaped slit and patch lines have been applied. Whole antenna dimensions including the ground plane are $35{\times}50{\times}1\;mm^3$, and the antenna part size is $35{\times}27\;mm^2$. It is fabricated on the FR-4 substrate(${\epsilon}_r=4.4$) using a microstrip line of $50{\Omega}$ for impedance matching. For the measured results, the impedance bandwidth below a VSWR of 2 is 790~916 MHz, 1.74~2.14 GHz, and 2.36~3.13 GHz. The fabricated antenna is satisfied with the aimed impedance bandwidth in GSM/DCS/US-PCS/UMTS/Bluetooth/S-DMB applications.

• Journal of the Korea Society of Computer and Information
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• v.20 no.6
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• pp.59-76
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• 2015

Recent wide spread of embedded devices and technology growth of broadband communication has led to rapid increase in the volume of created and managed data. As a result, data centers have to increase the storage capacity cost-effectively to store the created data. Data deduplication is one way to save the storage space by removing redundant data. This work propose IO extent based deduplication schemes called CORE-Dedup that exploits content-preserving access locality. We acquire IO traces from block device layer in virtual machine host, and compare the deduplication performance of chunking method between the fixed size and IO extent based. At multiple workload of 10 user's compile in virtual machine environment, the result shows that 4 KB fixed size chunking and IO extent based chunking use chunk index 14500 and 1700, respectively. The deduplication rate account for 60.4% and 57.6% on fixed size and IO extent chunking, respectively.