• The Journal of Society for e-Business Studies
• /
• v.15 no.4
• /
• pp.219-244
• /
• 2010

The charged broadcasting market has been becoming very competitive to get the limited media consumers since IPTV was introduced to the market. This research analyzed the competition among interactive broadcasting media. We employed the niche theory for comparing IPTV with Cable TV and Satellite TV, which are two major existing broadcasting media. For employing the niche theory, we focused on the gratification-opportunity features of the media caused by the consumers' gratification sought: ease of use, interactivity, variety of content, and economic feasibility. The results showed the extent to which media are utilized, the extent to which each pair of media are perceived as similar, and the competitive superiority between each pair of media on each dimensions. Finally, we examined the competition structure of IPTV and other broadcasting media, and proposed the competitive strategy for IPTV to get an advantages.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.30 no.6B
• /
• pp.406-415
• /
• 2005

The standards which use shared medium like IEEE 802.11 wireless LAN have transmission opportunity by contention in contention period. If there are collisions in contention period, medium access control protocol may solve problem by using backoff algorithm. Backoff algorithm is important part in medium access control, but legacy backoff method which is used under IEEE 802.11 standards is not adjusted when load is heavy because of increasing collisions. In this paper, we propose a new load-based dynamic backoff algorithm in contention-based wireless shared medium to improve throughput of medium and to reduce the number of collisions. Proposed backoff algorithm can increase the network utilization about $20\%$ higher than that of binary exponential backoff algorithm.

• Proceedings of the Korea Society for Simulation Conference
• /
• 1999.10a
• /
• pp.12-17
• /
• 1999

WATM(Wireless ATM)에서의 매체접근제어(Medium Access Control)는 QoS를 보장하기 위해 다양한 방식들이 제안되어 왔다. 현재까지 제안되어 온 매체접근제어 방식들은 시분할 다중화 방식 (TDMA)과 예약경쟁방식을 주로 사용하고 있다. 이때 활용되는 기능에는 QoS를 보장하기 위해 통계적 다중화, 스케쥴링 또는 예약 방식 등이 있는데 경쟁 방식은 아직까지 slotted-ALOHA를 그대로 사용하고 있다. Slotted-ALOHA방식의 단점을 개선하기 위하여 통계적 방식으로 경쟁을 제어하거나 물리적 방식으로 경쟁을 분리시켜 그 효율을 향상 시켜왔으나 우선 순위가 같은 이동국들이 많을 경우에는 해결할 방법이 없었다. 이러한 문제점들은 기지국 중심의 경쟁방식이라는 점이 그 문제를 해결하는데 있어서의 걸림돌이다. 본 논문에서는 이미 슬롯을 할당받은 동료 이동국에게 예약요청을 피기백킹(piggybacking)함으로써 신속하게 슬롯을 할당을 받을 수 있는 분산 경쟁방식을 제안한다.

• Electrical & Electronic Materials
• /
• v.1 no.3
• /
• pp.197-208
• /
• 1988

현재 특히 컴퓨터용 외부 기록매체분야에서 재래식 자성분말 코팅형 매체에 대해서 여러가지 보다 우수한 특성을 가진 경합재료가 경쟁적으로 개발되고 있다. 먼저 면재기록방식의 경우에 괄목할 발전을 하고 있는 것은 Co-Ni-P 및 Co-Ni계 무전해 혹은 스파터된 hard disk용 박막이다. 아직 오버코팅 문제가 완전히 해결되지 않고 그외 기판문제 등에서 개선의 여지가 많지만 그 수요가 급격히 늘고 있다. 그 다음으로 수직기록 방식 매체인데 현재는 Ba-ferrite분말도포매체가 공업적 공정측면에서 산업화에 가깝다. 이는 기존 테이프 메이커들의 설비활용이 가능하고 tribology, 안정성에서 비교적 문제가 적기 때문이다. 그러자 이 재료도 금속분말도포제와 특성이 비슷하고 분말자체 가격도 비슷해서 기존재료와 치열한 경쟁을 이겨야 산업화에 성공할 것으로 생각된다. 이보다 훨씬 고밀도기록이 가능한 소재중에서 Co-Cr수직기록박막이 가장 많이 연구되고 있어서 공업화 가능성이 높지만 head 재료의 개선, tribology 문제해결 등이 선행되어야 공업화가 성공될 것이다. 그러나 선진국 특히 일본, 미국에서 이러한 연구가 엄청나게 많이 진행되고 있어서 빠른 시일내에 산업화가 이루어질 것으로 기대된다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2011.10a
• /
• pp.633-636
• /
• 2011

The paper deals with the performance of contention-based medium access control (MAC) protocols for underwater sensor networks. We extensively analyze the number of received-packets and the end-to-end delay of ALOHA, CSMA, CSMA-RTS-CTS and CSMA-RTS-CTS-ACK protocols using a Qualnet underwater network simulator which accommodates diverse underwater acoustic channel environments. Using simulation results, we support an engineering table to determine an adequate contention-based MAC protocol for underwater sensor networks.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.13 no.5
• /
• pp.995-1002
• /
• 2018

A Contention Access Period(: CAP) with high contention in priority-based MAC protocols can result in higher number of collisions and retransmissions. High-Priority traffic dominates low-priority traffic during CAP depleting low-priority traffic, adversely affecting WBAN throughput, delay, and energy consumption. This paper proposes a Emergency data-First-Priority MAC(: EFP-MAC) superframe structure that is able to reduce contention in the CAP period, and provides a fair chance for low-priority traffic. As a result, the proposed Emergency data-First Priority MAC(; EFP-MAC) The Simulation results show that the proposed MAC achieves lower energy consumption, higher throughput and low latency than the IEEE 802.15.4 standard.

• Journal of Digital Contents Society
• /
• v.9 no.2
• /
• pp.213-223
• /
• 2008

This study attempted to analyze background and industrial difference of RO and SO. RO was launched for solving a problem of terrestrial broadcasting. After solving a problem of terrestrial broadcasting system, RO has played a roll as a local media. On the other hand, SO was launched by government's policy so SO has been protected and brought up by government. Because market of RO and SO is overlap and competitive, RO has been restricted by government for issuing new license and renewal of permission. Presently, environment of media has been changed very dramatically, so various niche media are needed for various customer's needs. In addition, local media are in trouble of playing a role as a public broadcasting service in Korea. Therefore, RO might be a good solution. In this study for the analysis of the user's needs a survey was conducted. This study shows possibility of RO's roll and function as a local media.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 2004.11a
• /
• pp.300-300
• /
• 2004

• (The) Korean Journal of Advertising
• /
• v.27 no.3
• /
• pp.113-139
• /
• 2016

The purpose of this study was to investigate perception of media characteristics inorder to provide a theoretical background for the media mix strategy. Considering the qualitative-vale of each medium, this study conducted a survey consisting of 60 academic and advertising industry experts to examine how they perceive and evaluate the characteristics of TV, radio, newspaper, OOH, Internet, mobile, and digital signage in terms of media effectiveness. The results, first, show that 'media engagement', 'effective reach', and 'behavioral targeting' are three most important indices to assess the media effectiveness. Second, the Internet was best evaluated in its various aspects according to the MAIX model, which gauges the effectiveness of each advertising medium. The study also proved that each advertising medium has unique advantages so that each medium should adopt a strategic positioning to differentiate it from other media. As such, this study provides meaningful evidences to understand the various characteristics and competitive value of advertising media and useful guidelines for media planning.

• Digital Contents
• /
• no.10 s.161
• /
• pp.30-34
• /
• 2006

급변하는 통ㆍ방 융합 시대를 맞아 케이블방송이 새로운 도전에 직면하고 있다. 그 동안 경쟁매체라고 해봐야 지상파와 위성방송 채널 정도였지만 이제 통신과 방송의 융합이라는 거대 조류 속에서 IPTV, TV포털 등 새로운 개념의 방송 서비스와 경쟁해야만 하기 때문이다. 새로운 경쟁자들이 속속 진입하고 있는 방송 시장에서 과연 케이블방송 업계가 수성에 성공할지 관심이 모아지고 있다.