• 한국군사과학기술학회지
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• 제13권4호
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• pp.577-585
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• 2010

The Military Tactical Communication technology for effective network-centric warfare is developing. Targeting broadband wireless transmission, core technology for connection, and Transmission technology that secure survivability under High-speed Movement environment. On the one hand, Tactical data communication system that reflects military characteristic is developing on the base of Legacy communication equipment which is used in the field. Because almost every military units in the field have used voice to communicate which lower efficiency of operation, they have made effort to Substitute voice communication which delays military Operation Tempo to digital communication. The Communications environment of troops in Forward edge of battle field area is very poor. Especially in terms of limited frequency allocation and bandwidth. Therefore, improving the efficiency of frequency is essential for Military Tactical Communication. This paper is about The Data Compression Method for increase of Efficiency in Tactical Data Communication over Legacy Radios which are UHF, VHF, HF Radio. I proposed and proved the most efficient Data Compression Method that reflects military characteristic, after analyzing the experimentation, which simulate CAS(Close Air Support mission) data transmission between Pilot and TACP.

• Journal of Positioning, Navigation, and Timing
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• 제9권4호
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• pp.293-304
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• 2020

In this paper, various modulation techniques, including the legacy Global Navigation Satellite System (GNSS) signal modulation techniques, are introduced and the spectral characteristics and correlation characteristics of signals with various modulation techniques are analyzed based on numerical simulation. With the development of various GNSS services, the limited frequency band has become increasingly saturated, and issues of interoperability and compatibility have emerged in the new GNSS design. Since the efficient allocation of frequency resources is closely related to spectrum design, modulation techniques are one of the important signal design parameters of new signal design. Signal modulation techniques are closely related to various figure of merits (FoMs) as well as spectrum characteristic, and in some cases there is a complicated trade-off between FoMs. Thus, the FoMs associated with modulation technology should be analyzed and the best signal candidates should be chosen carefully via the trade-off analysis for FoMs. In this paper, we define the modulation technique based on Phase Shift Keying (PSK), Binary Offset Carrier (BOC) and Continuous Phase Modulation (CPM) for the design of KPS signals, and the FoMs of signals in terms of spectrum and correlation function are evaluated. Signals with various modulation techniques are implemented through a numerical simulation, and the relevant FoMs are analyzed.

• 응용통계연구
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• 제35권1호
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• pp.147-159
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• 2022

오늘날 다양한 소셜 미디어 플랫폼이 널리 퍼져 있고 사람들은 그들의 일상생활 속에서 밀접하게 그러한 플랫폼들을 이용하고 있다. 이에 따라, 많은 수의 구독자, 시청, 댓글 등을 보유한 인플루언서들은 우리 사회 속에서 큰 영향력을 가지게 되었다. 이러한 추세에 따라 많은 회사들은 그들의 상품과 서비스 판매의 촉진을 위한 마케팅 목적으로 인플루언서들을 적극 활용하고 있다. 본 연구에서는 게임 마케팅을 위한 비디오에서 인플루언서들의 스피치를 추출하고 텍스트화하여 이를 텍스트 마이닝 기술을 이용하여 탐색적으로 분석한다. 분석에 있어, 성공한 마케팅 비디오와 실패한 마케팅 비디오를 구분하고 성공, 실패한 마케팅 비디오에서 인플루언서들의 언어적 특징들을 비교 분석한다.

• 대한조현병학회지
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• 제23권2호
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• pp.58-64
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• 2020

Objectives: In this study, we conducted an exploratory analysis of the current media trends on schizophrenia using text-mining methods. Methods: First, web-crawling techniques extracted text data from 575 news articles in 10 major newspapers between 2018 and 2019, which were selected by searching "schizophrenia" in the Naver News. We had developed document-term matrix (DTM) and/or term-document matrix (TDM) through pre-processing techniques. Through the use of DTM and TDM, frequency analysis, co-occurrence network analysis, and topic model analysis were conducted. Results: Frequency analysis showed that keywords such as "police," "mental illness," "admission," "patient," "crime," "apartment," "lethal weapon," "treatment," "Jinju," and "residents" were frequently mentioned in news articles on schizophrenia. Within the article text, many of these keywords were highly correlated with the term "schizophrenia" and were also interconnected with each other in the co-occurrence network. The latent Dirichlet allocation model presented 10 topics comprising a combination of keywords: "police-Jinju," "hospital-admission," "research-finding," "care-center," "schizophrenia-symptom," "society-issue," "family-mind," "woman-school," and "disabled-facilities." Conclusion: The results of the present study highlight that in recent years, the media has been reporting violence in patients with schizophrenia, thereby raising an important issue of hospitalization and community management of patients with schizophrenia.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권8호
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• pp.2736-2750
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• 2022

As demands for the maritime communications increase, a variety of functions and information are required to exchange via elements of maritime systems, which leads communication traffic increases in maritime frequency bands, especially in VHF (Very High Frequency) band. Thus, effective resource management is crucial to the future maritime communication systems not only to the typical terrestrial communication systems. VHF data exchange system (VDES) enables to utilize more flexible configuration according to the communication condition. This paper focuses on the VDES communication system among VDES terminals such as shore stations, ship stations and aids to navigation (AtoN) to address efficient resource allocation. We propose a resource management method considering a MIMO (Multiple Input Multiple Output) technique in VDES, which has been widely used for modern terrestrial wireless networks but not for marine environments by scheduling the essential communication resources. We introduce the general channel model in marine environment and give two metrics, spectral and the energy efficiencies to examine our resource scheduling algorithm. Based on the simulation results and analysis, the proposed method provides a possibility to enhance spectral and energy efficiencies. Additionally, we present a trade-off relationship between spectral and energy efficiencies. Furthermore, we examine the resource efficiencies related to the imperfect channel estimation.

• 동서간호학연구지
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• 제29권2호
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• pp.185-195
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• 2023

Purpose: The purpose of this study is to analyze changes of child welfare policies and provide insights based on the collection and classification of newspaper articles. Methods: Articles related to child welfare policies were collected from 1990, during the Kim, Young-sam administration, to May 9, 2022, under the Moon, Jae-in administration. K-Means clustering and keyword Term Frequency-Inverse Document Frequency analysis were utilized to cluster and analyze newspaper articles with similar themes. Results: The administrations of Kim, Young-sam, Kim, Dae-jung, Roh, Moo-hyun, and Park, Geun-hye were classified into two clusters, and the Lee, Myung-bak and Moon, Jae-in administrations were classified into three clusters. Conclusion: South Korea's child welfare policies have focused on ensuring the safety and healthy development of children through diverse policies initiatives over the years. However, challenges related to child protection and child abuse persist. This requires additional resources and budget allocation. It is important to establish a comprehensive support system for children and families, including comprehensive nursing support.

• 대한전자공학회논문지TC
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• 제49권5호
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• pp.1-6
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• 2012

최근의 스마트 라이프를 추구하는 경향은 자동차 활용에도 영향을 미치게 되었다. 자동차의 안전성 향상에 대한 만족도가 부족한 상황에서 첨단 통신, 제어 및 센싱 기술을 활용하여 운전자 및 도로 이용자의 안전성, 운전효율성 및 편리성을 향상시키는 차세대 스마트 자동차 서비스 개발이 진행되고 있다. 이러한 스마트 자동차 서비스용 통신기술로 특화되어 개발되고 있는 기술이 바로 WAVE(Wireless Access in Vehicular Environment)이다. 이와 관련하여 해외 업체들은 차량간 통신 기술인 WAVE 관련 부품, 플랫폼, 플랫폼 및 안전 서비스를 개발하고 있다. 국내 ITS 업체들도 관련 기술 확보 및 제품 개발을 추진하고 있지만 국내에는 WAVE용 주파수가 할당되어 있지 않다. 본 연구에서는 국내 WAVE 주파수 할당 여부를 판단하기 위해 필요한 기초 자료인 ITS 관련 표준화 동향, 국내외 ITS용 주파수 할당 현황, 국내 WAVE 주파수 할당시 문제점 및 주파수 간섭과 관련한 실험 결과를 토대로 국내 현실에 적합한 정책적 방향을 제시한다.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.1950-1957
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• 2015

Modern wind generators (WGs) are forced or encouraged to participate in frequency control in the form of inertial and/or primary control to improve the frequency stability of power systems. To participate in primary control, WGs should perform deloaded operation that maintains reserve power using speed and/or pitch-angle control. This paper proposes an optimization formulation that allocates the required reserve to WGs to maximize the kinetic energy (KE) stored in a wind power plant (WPP). The proposed optimization formulation considers the rotor speed margin of each WG to the maximum speed limit, which is different from each other because of the wake effects in a WPP. As a result, the proposed formulation allows a WG with a lower rotor speed to retain more KE in the WPP. The performance of the proposed formulation was investigated in a 100-MW WPP consisting of 20 units of 5-MW permanent magnet synchronous generators using an EMTP-RV simulator. The results show that the proposed formulation retains the maximum amount of KE with the same reserve and successfully increases the frequency nadir in a power system by releasing the stored KE in a WPP in the case of a disturbance.

• Journal of Communications and Networks
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• 제7권2호
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• pp.115-125
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• 2005

This paper discusses how to effectively design a next-generation wireless communication system that can possibly provide very high data-rate transmissions and versatile quality services. In order to accommodate the sophisticated user requirements and diversified user environments of the next-generation systems, it should be designed to take an efficient and flexible structure for multiple access and resource allocation. In addition, the design should be optimized for cost-effective usage of resources and for efficient operation in a multi-cell environment. As orthogonal frequency division multiple access (OFDMA) has turned out in recent researches to be one of the most promising multiple access techniques that can possibly meet all those requirements through efficient radio spectrum utilization, we take OFDMA as the basic framework in the next-generation wireless communications system design. So, in this paper, we focus on introducing an OFDMA-based downlink system design that employs the techniques of hybrid multiple access (HMA) and frequency group (FG) in conjunction with intra-frequency group averaging (IFGA). The HMA technique combines various multiple access schemes on the basis of OFDMA system, adopting the multiple access scheme that best fits to the given user condition in terms of mobility, service, and environment. The FG concept and IFGA technique help to reduce the feedback overhead of OFDMA system and the other-cell interference (OCI) problem by grouping the sub-carriers based on coherence band-widths and by harmonizing the channel condition and OCI of the grouped sub-carriers.

• 한국통신학회논문지
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• 제36권8A호
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• pp.730-740
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• 2011

현재 국내 라디오 방송은 디지털 방식이 아닌 아날로그 방식을 통해 서비스 되고 있다. 아날로그 방식은 디지털 방식에 비해 주파수 효율이 저하되는 등의 기술적인 한계를 가지고 있다. 디지털 라디오 방식중 하나인 HD Radio는 기존의 아날로그 스펙트럼 양 옆에 디지털 데이터가 실리는 방식으로 기존 아날로그 주파수의 재배치 없이 디지털 신호를 전송할 수 있다는 장점이 있다. 만약 아날로그와 디지털 신호가 동시에 존재하기 때문에 서로간에 간섭이 발생하면 원활한 수신이 불가능하므로 HD Radio와 기존FM방송 간의 간섭을 정확히 분석해야한다. 본 논문에서는 강릉 지역 괘방산 송신소를 기준으로 하고 전국의 103.5MHz 및 +-400kHz 이내의 주파수를 사용하는 기지국을 간섭국으로 지정하여 HD Radio 채널 배치 구조를 분석하였다. 본 논문을 통해 독자는 디지털 라디오 시스템의 주파수 간섭에 대한 참신한 정보를 얻을 수 있으리라 본다.