• Title, Summary, Keyword: 채널유형

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A Study on the MAC Protocol to Reduce the Delay Time in Aeronautical Mobile Communication (항공이동통신에서의 지연 시간 감소를 위한 MAC 프로토콜에 대한 연구)

  • Kim, Yong Joong;Kang, Seok Yub;Lim, Hyeong Yeol;Park, Hyo Dal
    • The Journal of Advanced Navigation Technology
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    • v.6 no.1
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    • pp.1-9
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    • 2002
  • 본 논문은 현재 무선 LAN 환경에서 적용되고 있는 매체접근제어 프로토콜인 IEEE 802.11 CSMA/CA를 이용함으로써, 음성 위주의 항공이동통신에서 음성과 데이터 채널을 통합하여 사용하도록 하고 있다. 또한, 표준으로 제정되어 있는 기존의 CSMA/CA 매체접근제어 프로토콜에 대한 이해를 바탕으로 성능 개선 방안을 제안하였으며, 이를 바탕으로 채널 효율을 향상시켰다. IEEE 802.11 매체접근제어(MAC, Medium Access Control) 프로토콜은 데이터 유형에 따라 채널을 두 개의 구간(PCF와 DCF 구간)으로 나누어 전송하도록 하고 있다. 본 논문에서는, 데이터 유형별로 적용되는 구간 중, DCF 구간에서의 패킷간의 충돌 가능성을 줄임으로써 데이터 전송 효율을 높이는데 주안점을 두고 있다. 제안 방안으로는 경쟁 구간에서의 전송에서 충돌에 따른 손실을 보완할 수 있도록 Wireless Window Protocol(이하, WWP)을 적용한 후 전송 과정을 제어하였다. Hidden 터미널의 영향이 적으므로 가시권내 통신에 적합한 기존의 2-Way CSMA/CA 프로토콜을 항공통신에 적용하여 상태 천이 과정을 5개에서 6개로 세분화하였고, 주어진 확률에 의하여 나누어진 두 개의 그룹별로 상태 천이 과정을 다르게 적용하였다. 따라서, 채널이 한 항공기에 의해 점유되는 PCF를 제외한, DCF 구간에서의 데이터 전송 효율을 높일 수 있었다. 시뮬레이션은 채널 대역폭과 패킷 크기 등을 파라미터 값으로 하여 수행하였으며, 시뮬레이션 결과 CSMA/CA에 비해 새로 제안한 알고리즘이 데이터 전송 과정에서 발생하는 충돌 가능성을 감소시킴으로써 성능이 향상됨을 알 수 있었다.

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Improvement and Performance Evaluation of Uplink Scheduling Method for the High-speed Portable Internet System (휴대인터넷에서 상향링크 스케줄링 방법의 개선 및 성능 평가)

  • Kim, Kyung-Hee;Baek, Jang-Hyun
    • Journal of the Korea Society for Simulation
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    • v.15 no.2
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    • pp.41-50
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    • 2006
  • The high-speed portable internet service will be served in Korea sooner or later. However, the scheduling method for the packets of various service classes has not been determined clearly yet. An effective packet scheduling for various service classes requiring different QoS is necessary to increase the efficiency of radio channels that are the limiting resource. This paper proposes an improved uplink scheduling method to accommodate more calls and enhance channel efficiency. Suggested scheduling method reflects different channel conditions considering terminal's location within a cell to increase the transmission rate and utility of the channels. According to our simulation results, our proposed scheduling method shows a good performance in the aspect of throughput and capacity of uplink channels.

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Temperature Compensation of 8 Channel DWDM Multiplexer Using All Optical fiber Mach-Zehnder Structure (전광섬유형 8채널 DWDM용 광다중화기의 온도보상 특성)

  • Chang, Jin-Hyeon;Jung, Jin-Ho;Kim, Young-Kwon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.30 no.8A
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    • pp.697-704
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    • 2005
  • In this paper, Passive Temperature Compensation Technology is apply to 8-channel Optical multiplexer with 1000Hz channel spacing. The 8-channel multiplexer is fabricated by connecting three cascaded Mach Zehnder Interferometer(MZI) of optical fiber type, and each interferometer has the wavelength interval of 100GHz, 2000Hz and 4000Hz, respectively. Furthermore, to acquire uniform insertion loss, it is fabricated by using Wavelength Flatten Coupler(WFC) in which the variation of insertion loss is low. $CO_2$ laser to adjust precisely the wavelength. The optical fiber is very sensitive in the thermal variation around. Thus, When fabrication the prototype, it is applied a technique to compensate the optical thermal effect because the center wavelength at the output is shifted according to the thermal variation around. In summary, The prototype composed by eight cascaded MZI has an insertion loss of 5.5 dB, the bandwidth of 0.8nm at 0.5 dB point, and channel crosstalk of 25 dB. Furthermore, the loss dependent on polarization is measured as 0.06dB. Consequently, the output wavelength is shifted within 0.05 m when the surrounding temperature varies until $60^{\circ}C$

Study on the Type of Selecting Channels through the On-Line about Restaurant Information by Baby Boomer Consumers (베이비부머 소비자의 온라인을 통한 외식정보채널유형 선택에 관한 연구)

  • Choi, Soo Ji
    • 한국노년학
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    • v.36 no.3
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    • pp.711-726
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    • 2016
  • The purpose of this study was to analyze to 1) the differences according to demographic characteristics 2) select the type-specific communities online channels of the baby boomer customers group, who ever search for restaurant information through on-line for the previous three months. The study was based on a total of 280 samples obtained from on-line networking service users in a metropolitan area from April 15 to 30, 2016. The major findings are as follows. The data were analysed using frequency, factor analysis, cluster analysis and ${\chi}^2test$. According to the results of factor analysis, on-line utilizing attributes were separated into three factors: commitment of useful information, activity of leading on-line, and habit. The based on a factor analysis, cluster analysis was adopted to segment baby boomer customers. The identified four clusters showed in using on-line: type of active utilization, habit, seeking information and passive utilization. The clusters had significant differences in gender and monthly income by demographics. All of four clusters selected blog, face book, twitter in turn through the personal on-line channels. Cluster type of active utilization and habit selected restaurant home pages, restaurant blog, restaurant face book, restaurant twitter in turn through the public on-line channels. Cluster type of seeking information and passively utilization selected restaurant home pages, restaurant blog, restaurant twitter, restaurant face book in turn through the public on-line channels. Implications and future research were also discussed.

Exploring the Technology Fit of Digital Media on Product Shopping Task (디지털 매체 기술과 제품 구매 태스크의 적합성 탐색)

  • Han, Hyun-Soo;Joung, Seok-In
    • The Journal of Society for e-Business Studies
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    • v.16 no.4
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    • pp.283-299
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    • 2011
  • In this paper, we draw upon Task-Technology Fit theory to investigate the fit attributes which impacted on customer preference over three virtual shopping channels which included TV home shopping, Internet shopping, and broadband applications, i.e. IPTV. The fit attributes also reflected the product category contingency, which is classified based on the degree of quality assessing difficulty on the web, such as quasi-commodity, look and feel goods, and look and feel with variable quality goods. Using the collected survey data, we employed stepwise regression analysis to validate the fit attributes in the context of performing virtual shopping task via those three distinctive media technologies. Furthermore, through ANOVA test with Duncan statistics, we reported comparative intensity of the valid fit attributes across the product categories and distinct media technologies. The results validated four critical fit attributes and significant distinctions among product categories and three virtual shopping channels. The findings provide practical insights in distribution channel design exploiting digital convergence technologies.

A comparison study on price discount of bi-national product (복합원산지제품의 가격할인에 대한 비교연구)

  • Lee, Jiwon;Jin, Sungmin;Kang, Inwon
    • International Commerce and Information Review
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    • v.18 no.2
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    • pp.169-194
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    • 2016
  • This study aims to explain the cause of price differences of bi-national products based on consumer response of product type, distribution channel, and consumer nationality, respectively. Specifically this study investigated whether price discount and distribution channel affect consumer evaluation by luxury and non-luxury product type. In the case of bi-national product toward the non-luxury, price discount had positive influence on preference, regardless of distribution channel. By revealing the influence of price discount on bi-national products on consumer response of product type and distribution channel respectively, the study suggests meaningful implications for the strategic management of bi-national products.

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Estimation of Channel Capacity for Data Traffic Transmission (데이터 트래픽 특성을 고려한 적정 채널 용량 산정)

  • Park, Hyun Min
    • The Journal of the Korea Contents Association
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    • v.17 no.3
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    • pp.589-595
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    • 2017
  • We present an estimation model for optimal channel capacity required to data traffic transmission. The optimal channel capacity should be calculated in order to satisfy the permitted transmission delay of each wireless data services. Considering the discrete-time operation of digital communication systems and batch arrival of packet-switched traffic for various wireless services, $Geo^x$/G/1 non-preemptive priority queueing model is analyzed. Based on the heuristic interpretation of the mean waiting time, the mean waiting times of various data packets which have the service priority. Using the mean waiting times of service classes, we propose the procedure of determining the optimal channel capacity to satisfy the quality of service requirement of the mean delay of wireless services. We look forward to applying our results to improvement in wireless data services and economic operation of the network facilities.

Exploring Types of Verbal Violence Through Speech Analysis on Non-facing Channels (비대면 채널에서의 음성분석을 통한 언어폭력 유형 탐색)

  • Kim, Jongseon;Ahn, Seongjin
    • The Journal of Korean Association of Computer Education
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    • v.23 no.3
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    • pp.71-79
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    • 2020
  • This study investigates the rising issue of verbal violence at non-facing channels. Focus Group Interview(FGI) was conducted to examine verbal violence occurred during emotional labors in real-life cases. In addition, the distribution of verbal violence in the conversation was confirmed through a new big data technology called Speech Analysis(SA). The result findings highlighted the two perspectives as below. First, verbal violence occurred through calls, is classified into personal insult, swearing/verbal abuse, unreasonable demand, (sexual) harassment and intimidation/threat. Second, Speech Analysis result exhibited the most frequently appeared verbal violence were personal insult and swearing/verbal abuse. Informal language use and speaking in disrespectable manner was the highest rate in personal insult category. Moreover general cursing was the highest rate in swearing/verbal abuse category. In particular, the rate of using curse language was the highest in overall cases of verbal violence. This study summarizes the types of verbal violence that occur in non-facing channels and suggests a need for further investigation on how verbal stress affects working environment for emotional labor.

The Effect of E-Finance on Bank Performance and Its Determinants in Korea (전자금융채널의 경영성과에의 영향 및 결정요인 연구)

  • Kim, Hoe-Sook;Choi, Seung-Bin
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.6 no.2
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    • pp.25-50
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    • 2011
  • The purpose of this study is to investigate the difference of performance between banks with electronic-based banking service and banks without electronic-based banking service in Korea. The performance indicators we use are DEA efficiency and profitability such as NI, ROA and ROE. The findings are that the performance of bank with electronic banking service are significantly different from that of bank without electronic banking service in DEA efficiency, financial efficiency(cost and revenue) and profitability. But there are some differences among the type of electronic-based service channel that banks provide. The banking channels comprise two major groups: the traditional channels and e-channels. E-channels provide cost-saving for banks and their clients. Among them, only card-related ATM significantly affects the profitability of banks in the positive direction, and technical efficiency also affects the bank's profitability. But the others do not affect.

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Performance Evaluation of Dual Mode Packet Data Service in the IMT-2000 System (IMT-2000에서 이중 모드 패킷 데이터 서비스의 성능 분석)

  • 반태원;이상민;조유제
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.26 no.9A
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    • pp.1592-1600
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    • 2001
  • 본 논문에서는 IMT-2000을 위한 이중 모드 패킷 전송 방식에 대한 성능을 분석하고, 동적 임계치 설정을 이용한 이중 모드 패킷 전송 방식을 제안한다. 먼저, 다양한 채널 환경과 트래픽 유형을 고려하여, 공용 채널과 전용채널 간의 모드 전환을 위한 임계치의 변화에 따른 성능의 변화를 고찰하였다. 성능 분석 결과, 채널 환경과 트래픽 형태에 따라서 스위칭 임계치 설정이 매우 중요하며, 성능에 큰 영향을 미치게 된다는 것을 알 수 있었다. 그리고, 이중 모드 방식에서 스위칭 임계치를 동적으로 설정하는 방식을 제안하고 시뮬레이션을 통해 성능을 분석하였다. 제안된 동적 임계치를 사용할 경우에 채널 상황이나 트래픽 특성 변화에 적응적으로 대처할 수 있어, 전반적으로 고정 임계치 방식보다 성능이 크게 개선됨을 알 수 있었다.

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