• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.7 no.2
• /
• pp.216-233
• /
• 2013

Conventional optimization designs of wireless networks mainly focus on spectral efficiency (SE) as a performance metric. However, as diverse media services are emerging, a green wireless network, which not only meets the quality of experience (QoE) requirements for users and also improves energy efficiency (EE), is the most appropriate solution. In this paper, we firstly propose the unit QoE per Watt, which is termed QoE efficiency (QEE), as a user-oriented metric to evaluate EE for wireless networks. We then analyze which is the kind of wireless resource given priority to use under different scenarios to obtain an acceptable QEE. Particularly, power, delay and data-rate related to QoE are separately addressed for several typical services, such as file download, video stream and web browsing services. Next, the fundamental tradeoffs are investigated between QEE and SE for wireless networks. Our analytical results are helpful for network design and optimization to strike a good balance between the users perceived QoE and energy consumption.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2003.11a
• /
• pp.23-26
• /
• 2003

3차원 Polygonal Mesh는 그래픽스, 에니메이션, 게임에서 3차원 객체에 대한 표현에 사용되고, 이러한 3차원 모델에 대한 IndexedFaceSet 노드에 3차원 정전정보와 연결정보를 압축하는데 MPEG-4 3DMC를 사용한다. 이러한 연결정보는 다각형의 Mesh 형태로 3차원 모델을 구성하는 정보를 갖는데, 이는 Tepological Surgery 라고 하는 방법을 통해서 2차원의 스트립 단위의 데이터로 분해된다. 이러한 3D 데이터는 방송환경과 같은 재전송이 불가능한 네트워크의 환경에서 유무선 네트워크 상에서 채널문제로 인해서 데이터의 손실이 있게 되면, 복호화 된 데이터는 데이터의 손상이 발생하게 된다. 이러한 현상은 3D 모델의 좌표의 연결정보에 손상을 주게 되고, 여기서 복호화 된 데이터는 스트립 단위로 손상이 발생하게 된다. 이러한 현상은 3차원 모델의 좌표의 연결정보에 손상을 주게 된다. 본 논문은 이러한 3차원 정보의 손상을 효과적으로 복원하기 위한 연구에 관한 것이며, Mesh의 면을 이루는 각 꼭지점의 좌표들의 연결 정보가 손실되지 않는 스트립에서는 약간의 차이는 있을 수 있으나, 완벽한 복원을 하였고, 두 개 이상의 스트립이 붙어서 손상된 경우나, 좌표의 연결 정보가 없는 경우에는 조건에 따라 현저히 좋은 격과를 얻을 수 있었다.

• Journal of IKEEE
• /
• v.22 no.4
• /
• pp.1068-1072
• /
• 2018

In underwater communications, there are many challenges due to energy limitations, long propagation delay, low data rate, and high power loss, unlike terrestrial RF communications. Especially, the propagation delay of underwater acoustic channel is five orders of magnitude higher than in electro-magnetic terrestrial channels due to the low speed of sound(1,500m/s). Thus, the MAC protocols for terrestrial communications are not suitable for underwater network. In this paper, we studied the considerations for MAC protocol in underwater acoustic channel. Here, we concentrated on CSMA based MAC protocols. From the results, we confirmed that the number of control packets has an important effect on the performance in underwater environment. These results would be useful in designing MAC protocols for underwater acoustic communications.

• Archives of design research
• /
• v.18 no.4 s.62
• /
• pp.205-214
• /
• 2005

The purpose of this study is to find an efficient marketing strategy in terms of media channel communications using one specific case study. Results of previous studies have shown that consumers' exposure to TV, newspaper, radio and magazine related to description of corporate image tends to be influential for consumers' product image, which mainly consists of product preference, expertise, and credibility. It means that media strategy should be different, depending on what kinds of image they try to be purposive. In conclusion, we concluded that TV and radio should be the best vehicle for increasing consumers' positive preference rather than those of newspaper and magazine. Newspaper and magazine are also influential in terms of expertise, and newspaper and magazine should be better than TV and radio in terms of credibility. The results of this study should be similar to previous studies in that TV and radio should be more inducing interest, and print media should be more credible than TV and radio.

• Korean journal of communication and information
• /
• v.34
• /
• pp.244-274
• /
• 2006

To explore the social construction of the concept of leadership, image of media mogul depicted in the popular business newspaper, the Wall Street Journal, was analyzed. Then, the reconstructed image of the CEO was compared with the firm's stock price change to see their relationship, if any. This paper focused on the case of Steve Case (previous chairman of AOL Time Warner), who was the leader of the world largest media company. The period for the analysis was three years and five months from his inauguration(January 2000) to the resignation(May 2003). In general, CEO of a firm represents the firm itself. Thus, the image of the CEO is highly transcends to the image of the firm as well. Consequently, the image of CEO might have an impact on the firm's performance. Since business newspaper works as one of the most important information intermediaries in the stock market, the image of CEO constructed in the newspaper might be a critical indicator for the investors. The results revealed that media coverage of Steve Case was commensurate with the financial performance, particularly stock price change of the AOL Time Warner.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.9B
• /
• pp.923-930
• /
• 2009

Digital Rights Management(DRM) is a term that refers technologies for imposing limitations on the use of digital content for protecting media copyright holders. This paper proposes a generic scheme for digital media copy protection that can be applied to any digital media such as audio, video, etc. The scheme will make it very hard to play a copied content on a foreign platform and to guess secret content encryption keys. Unlike other DRM techniques, the scheme uses the stream cipher HC-256 only for encrypting media content and it allows a client to start content playback immediately following its streamed decryption. As to the encryption, it requires to generate several secret keys for each new client(player copy), rather than for each media content, which makes it scalable in terms of managed keys. Also, for simplicity, the scheme supports the popular unlimited-play-after-download policy only, which would eliminate the necessity for deploying separate server or process for licensing.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.34 no.1B
• /
• pp.67-73
• /
• 2009

This paper proposes a new fast vertical handover mechanism to optimize and enhance the existing fast vertical handover HMIPv6(FV-HMIP) mechanism in heterogeneous wireless access networks. The proposed mechanism ad opts the IEEE 802.21 Media Independent Handover Function(MIHF), and thus is called the "MFV-HMIP". The Media Independent Handover Service (MIIS) in the IEEE 802.21 MIHF is extended by including new L3 inform ation to provide domain prefixes of heterogeneous neighbouring mobility anchor points(MAPs). This can eliminate the heterogeneous neighbouring MAP discovery phase in the existing FV-HMIP. Thus, the proposed MFV-HMIP can reduce the signalling traffic over wireless link and increase the possibility of predictive mode operation. Therefore, the proposed MFV-HMIP mechanism can be superior to the existing FV-HMIP mechanism for wireless resource efficiency, handover latency, and packet loss. Through analytic performance evaluations and computer si mulations, the proposed mechanism can be shown to optimize and enhance the existing mechanism.

• Journal of Korean Academy of Nursing
• /
• v.47 no.6
• /
• pp.806-816
• /
• 2017

Purpose: As comprehensive nursing care service has gradually expanded, it has become necessary to explore the various opinions about it. The purpose of this study is to explore the large amount of text data regarding comprehensive nursing care service extracted from online news and social media by applying a semantic network analysis. Methods: The web pages of the Korean Nurses Association (KNA) News, major daily newspapers, and Twitter were crawled by searching the keyword 'comprehensive nursing care service' using Python. A morphological analysis was performed using KoNLPy. Nodes on a 'comprehensive nursing care service' cluster were selected, and frequency, edge weight, and degree centrality were calculated and visualized with Gephi for the semantic network. Results: A total of 536 news pages and 464 tweets were analyzed. In the KNA News and major daily newspapers, 'nursing workforce' and 'nursing service' were highly rated in frequency, edge weight, and degree centrality. On Twitter, the most frequent nodes were 'National Health Insurance Service' and 'comprehensive nursing care service hospital.' The nodes with the highest edge weight were 'national health insurance,' 'wards without caregiver presence,' and 'caregiving costs.' 'National Health Insurance Service' was highest in degree centrality. Conclusion: This study provides an example of how to use atypical big data for a nursing issue through semantic network analysis to explore diverse perspectives surrounding the nursing community through various media sources. Applying semantic network analysis to online big data to gather information regarding various nursing issues would help to explore opinions for formulating and implementing nursing policies.

• Korean journal of communication and information
• /
• v.36
• /
• pp.348-373
• /
• 2006

In the era of digital media, one of the most distinctive characteristics is the activity what audience play. This characteristic can be particularly demonstrated in the case of PPV(Pay-Per-View) use. Since this service is related with payment by audience according to each behaviour of their own media use. In doing so, this paper explores the characteristics and behavioral pattern in PPV use. In particular, the study tries to predict from the result that which trait of characteristic can explain the adoption of PPV. The analytical result shows that PPV users are much more active in gathering information as well as achieving the diversity in terms of program choice compared to non PPV users. At the same time, PPV users are prone to be unsatisfied against the other media and naturally willing to adopt the new media. PPV users are much more keen to use toward age related programme classification system in order to protect their children from inappropriate programmes. The variable of participational behaviour is the most relevant variable to predict the degree of PPV use, however, it fails to predict to distinguish the PPV users group from non PPV users group. It maybe given as a conclusion that PPV users are much more active in not only choosing their own program they like to watch but also planning ahead for maximising their pleasure from viewing.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.40 no.3
• /
• pp.506-515
• /
• 2015

In this paper, we propose a group playback synchronization method using adaptive synchronization delay time by the bit rate of media to synchronize a play position of streaming media between mobile smart devices. This method consists of streaming server-side and client-side synchronization algorithms based on synchronization delay time which includes connection time, control packet transmission time, streaming data buffering time, and synchronization processing time. We implement the Android media player application with synchronization support using the proposed algorithms and present the result of performance evaluation.