• Journal of Broadcast Engineering
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• v.14 no.6
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• pp.796-806
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• 2009

SVC (Scalable Video Coding) is a new video coding standard to provide convergence media service in heterogeneous environments with different networks and diverse terminals through spatial-temporal-quality combined flexible scalabilities. This paper presents the performance analysis on packet loss in the delivery of SVC over IP networks and an efficient adaptation method to packet loss caused by buffer overflow. In particular, SVC with MGS (Medium Grained Scalability) as well as spatial and temporal scalabilities is addressed in the consideration of packet-based adaptation since finer adaptation is possible with a sufficient numbers of quality layers in MGS. The effect on spatio-temporal quality due to the packet loss of SVC with MGS is evaluated. In order to minimize quality degradation resulted by packet loss, the proposed adaptation of MGS based SVC first sets adaptation unit of AU (Access Unit) or GOP corresponding to allowed delay and then selectively discards packets in order of importance in terms of layer dependency. In the experiment, the effects of packet loss on quantitative qualities are analyzed and the effectiveness of the proposed adaptation to packet loss is shown.

• Korean Journal of Plant Resources
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• v.21 no.3
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• pp.184-191
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• 2008

This experiments were carried out to find out the effects of different explant materials, kinds and concentration of plant growth regulators, and total nitrogen and sucrose contents on the in vitro regeneration of Abeliophyllum distichum Nakai. The effects of growth regulators on regeneration from 3 explant sources (leaf, internode and node) were more or less same. Leaf explants produced only callus with 2ip (Isopentenyladenine) and NAA (Naphthaleneacetic acid) treatment and other regulators had no effects. Test with internode explants yielded about same results but callus was obtained with 2,4-D (2,4-Dichlorophenoxyacetic acid). Node explants resulted in shoot regeneration by all regulator treatment except NAA and 2,4-D, but control also showed similar results. Callus formation from internode and node explants was vigorous by 2ip, zeatin, and 2,4-D treatments and high NAA concentration resulted in higher callus formation. In this experiment, various mixed treatment of growth regulators were also employed, using node as explant material. Shoot regeneration was obtained with BA (Benzyl adenine) + NAA treatments but the results were comparable with control. Generally shoot and root regeneration was poor with all combined treatment except 2ip + NAA and 2,4-D + NAA. However, callus was formed readily with all treatments. In this experiment, combined treatments of regulators were applied on the callus derived from singular regulator treatment. The results showed no shoot and root regeneration with any combination of 2,4-D, IAA (Indoleacetic acid) and NAA, but soft milky white callus was formed in all the treatments. No shoot and root regeneration was observed with any combination of 2iP, NAA and IAA, but somewhat hard, light green callus was formed in all the treatments. Callus formation decreased with high kinetin concentration in case of kinetin + NAA treatment. The experiments with total nitrogen content of media showed that low concentrations of 15 and 30mM were effective for the shoot and root regeneration. Sucrose experiment demonstrated shoot regeneration with 1${\sim}$4% concentration, and root and callus formation with 2${\sim}$4%. No root and callus formation was observed with 0 and 1% sucrose.

• Smart Media Journal
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• v.8 no.2
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• pp.29-38
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• 2019

With the advancement of information and communication technology, tactical networks are continuously being converted to All-IP future tactical networks that integrate all application services based on Internet protocol. Futuristic tactical mesh network is built with tactical WAN (wide area network) nodes that are inter-connected by a mesh structure. In order to guarantee QoS (quality of service) of application services, tactical service mesh (TSM) is suggested as an intermediate layer between infrastructure and application layers for futuristic tactical mesh network. The tactical service mesh requires dynamic QoS monitoring and control for intelligent QoS coordination. However, legacy networking nodes used for existing tactical networks are difficult to support these functionality due to inflexible monitoring support. In order to resolve such matter, we propose a tactical mesh WAN node as a hardware/software co-designed networking node in this paper. The tactical mesh WAN node is conceptually designed to have multi-access networking interfaces and virtualized networking switches by leveraging the DANOS whitebox server/switch. In addition, we explain how to apply eBPF-based traffic monitoring to the tactical mesh WAN node and verify the traffic monitoring feasibility for supporting QoS coordination of tactical-mesh traffic.

• Journal of Broadcast Engineering
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• v.23 no.6
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• pp.790-799
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• 2018

UHD broadcasting based on ATSC 3.0 is being implemented in Korea, and discussion on mobile broadcasting based on ATSC 3.0 is underway. The ATSC 3.0 standard introduces internet protocol based standards in order to facilitate the implementation of conventional broadcasting services as well as broadcasting and communication convergence services interlocking with communication services. In this process, various requirements for the receiver have been derived, and factors to consider for developing the receiver product have also increased. ATSC 3.0 broadcasting is currently in the introduction stage of the service, and additional technology development and product implementation related to the receiver should proceed until the full-scale market is formed. In this regard, this paper describes the considerations for developing UHD receiver based on ATSC 3.0 and the test procedure for verifying developed receiver.

• Journal of Broadcast Engineering
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• v.23 no.5
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• pp.682-692
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• 2018

In this paper, we propose an ARQ packet error control scheme using multiple threads in delivering massive capacity of multimedia based on MMT(MPEG Media Transport) protocol. On the sending side, each frame that constitutes an image is packetized into MMT packets based on MMT protocol. The header of the packet stores the sequence number of the frames contained in the packet and the time of presentation information. The payload of the packet stores the direct information that comprises the frame. The generated MMT packet is transmitted to the IP network. The receiving side checks if any error has occurred in the received packet. For any identified error, it controls the error through ARQ error control scheme and reconfigure the frame according to the information stored in the header of the received packet. At this point, a multi-threading based transport design is constructed so that each thread takes over a single frame, which increases the transmission efficiency of massive capacity multimedia. The efficiency of the multi-threading transport method is verified by solving the problems that might arise when using a single-thread approach if packets with errors are retransmitted.

• Journal of Forest and Environmental Science
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• v.29 no.4
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• pp.275-281
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• 2013

To establish in vitro nodal culture conditions of Echinosophora koreensis Nakai, one of rare and endangered species famous for beautiful flowers in the Korean Peninsula, the influence of plant growth regulators (PGRs) on shooting and rooting from in vitro shoots was investigated. In shoot multiplication, addition of 6-benzylaminopurine (BA) to the half-strength Driver and Kuniyuki's media in the range of 2.22 to 8.88 ${\mu}M $induced 2.5 to 2.7 shoots per axillary bud; and addition of 2.27 ${\mu}M $ thidiazuron (TDZ) produced 3.2 shoots, during 4 weeks of culture, while zeatin and isopentenyl adenine (2ip) were not effective on shoot multiplication as observed from several combination treatments of BA with other PGRs. Shoots established were smaller than 2 cm in length, in most of the treatments. while in BA 8.88 ${\mu}M $ treatment more than 30% of shoots were longer than 2 cm and shorter than 4 cm. In rooting, naphthalene acetic acid (NAA) from 5.37 to 21.48 ${\mu}M $ showed the rooting rate from 40.0 to 62.5%. Indole butyric acid (IBA) addition had little effect on rooting (<10%), although some roots in IBA-containing media were longer than those in NAA. Micropropagation from axillary buds of nodular explants was applicable and promising to multiplication and conservation of Echinosophora koreensis Nakai.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.152-154
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• 2012

2011년 3월 11일 일본 혼슈 센타이 부근 해역에서 발생한 규모 9.0의 지진에 의한 쓰나미로 동북부 지역에 엄청난 피해가 발생함에 따라 우리나라에서도 지진을 비롯한 각종 대규모 자연재해 대비를 위해 재난방송에 대한 체계를 전반적으로 재점검해야 한다는 의견이 나오고 있다. 지금까지 우리는 재난이 발생하면 TV나 라디오 등 전통적인 매체에 의존하고 있으며 실제 이러한 매체는 지금까지 국민들에게 신속하게 재난정보를 알리는 중요하고도 충실한 역할을 담당해 오고 있다. 그러나 지난해 일본의 쓰나미와 같이 인간의 능력으로 감당하기 힘든 대규모 재난이 발생하였을 경우 이러한 전통적인 재난 방송 매체만으론 역 부족이 될 수 있고, 실제로 일본에서 효과를 나타낸 것은 인터넷 전화(VoIP)와 SNS(Social Network Service) 등 뉴미디어로 구글, 페이스 북과 국내의 NHN, 다음 등은 실종자 정보와 피난처 정보를 제공하고 피해자의 안위를 확인할 수 있는 서비스 하는 등 필요한 정보를 실시간으로 알리는 새로운 매체로 큰 역할을 했다는 평가를 받았다. 본 논문에서는 뉴미디어를 재난방송 전달 매체로 활용하기 위해 현재 운영되고 있는 재난방송 체계 및 시스템의 조사를 통해 개선되어야 할 사항을 도출한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1144-1147
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• 2009

멀티미디어의 방송 서비스 제공하기 위해서 IP 멀티캐스트의 대안으로써 현재의 인터넷 환경에서도 동시 접속자 수의 제한과 자원 낭비 문제를 효과적으로 해결할 수 있는 다양한 오버레이 멀티캐스트 기법이 제시되고 있다. 본 논문에서는 멀티미디어의 방송 서비스 제공을 위한 병렬 미디어 스트리밍 서버(PMSS : Parallel Media Streaming Server)시스템에 대해 알아보고 오버레이 멀티캐스트 트리 구성 방안으로 분산형 Tree-First 기반의 Spanning tree 구조의 하나인 TBCP기법에 대해 설명하고, TBCP기법의 한계점을 극복하기 위한 오버레이 멀티캐스트 기반의 알고리즘 적용한 효율적이고 향상된 성능을 제공하는 miniOverlay Broadcasting Control Protocol (mOBCP)에 대해 알아본다. 또 제안한 mOBCP 멀티캐스트 기법을 기반으로 PMSS를 이용하여 오버레이 방송 서비스를 제공하는 방안에 제시한다. 성능 비교는 Single 서버와 PMSS로 멀티미디어 방송 서비스를 제공했을 때의 지연시간(Latency)를 비교해 보고 mOBCP기법과 TBCP기법을 PMSS 시스템에서 적용하여 사용자 요구량에 따른 서비스 받는대 걸리는 지연시간을 비교함으로써 제안된 기법의 효율성을 보여주고 있다.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.60-60
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• 2020

To establish in vitro axillary bud culture conditions of Echinosophora koreensis Nakai, one of Korean endemic endangered species famous for beautiful flowers, we tested the influence of plant growth regulators (PGRs) in shooting and rooting stage from in vitro plants. In shoot multiplication, addition of 6-benzylaminopurine (BA) to the media induced 2.5 to 3 shoots per bud during 4 weeks of culture. And media including 0.5 mg L^-1 thidiazuron (TDZ) produced 3 to 4 shoots per bud. However, zeatin and isopentenyl adenine (2-ip) were not successful to increase shoot number, and the combination treatments of BA with other PGRs were also not effective. Shoots were smaller than 2 cm in length, in most of the treatments. In rooting, naphthalene acetic acid (NAA) treatments in the range of 0.5 to 4.0 mg L^-1 appeared to increase rooting rate by 10% to 60% approximately when compared with the control but roots developed with callus clusters. Indole butyric acid (IBA) addition had little effect on rooting (below 10%), while some roots were longer than in NAA treatments and some shoots were longer on high IBA concentrations (4.0 to 8.0 mg L^-1). It is suggested that micropropagation is a highly applicable and promising to multiplication and conservation of rare and endangered endemic species.

• Journal of Broadcast Engineering
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• v.17 no.2
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• pp.207-222
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• 2012

Recently, many consumer electronics manufacturers have produced 3D devices such as 3DTVs and 3D monitors as interests in a stereoscopic video service are getting increased. However, most of 3D services are focused on local storage or bandwidth guaranteed service since 3D stereoscopic video service require bandwidth more stable and larger. This property causes difficulties in seamless stereoscopic video streaming services under IP based open network environment that cannot guarantee quality of services. In order to achieve a seamless video streaming service the international standard organization MPEG (Moving Pictures Experts Group) has developed the adaptive HTTP streaming technology called as DASH (Dynamic Adaptive Streaming over HTTP). However, the DASH doesn't have obvious scheme which can express the two elementary video streams based service-compatible stereoscopic contents in one segment. Therefore, this paper proposes a scheme of efficient 3D adaptive streaming service based on the DASH, which covers not only frame-packing stereoscopic contents but also service-compatible ones. The 3D adaptive HTTP streaming scheme introduced in this paper is able to provide 3D contents with various qualities to user and also has benefit that single 3D content can be applied to a variety of devices.