• Proceedings of the IEEK Conference
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• 2000.11c
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• pp.77-80
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• 2000

본 논문에서는 JPEG 영상을 인터넷상에서 효율적으로 전송하기 위한 Partial Access를 지원하는 JPEG 변환 처리 기술을 제안한다. 네트웍 상에서 영상을 전부 전송하지 않고 클라이언트의 브라우져의 디스플레이에 필요한 부분만을 실시간으로 전송한다면 전체 네트웍 효율을 높일 수 있다. 이를 위해서는 영상을 Partial Access 할 수 있어야 한다. 또한, 본 논문에서 제안한 Partial Access 기능이 추가된 JPEG 영상은 기존의 JPEG과 완전 호환되며, 클라이언트는 기존의 일반 웹 브라우져를 그대로 사용할 수 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.643-646
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• 2005

본 논문에서는 IP 통신망의 특성을 고려하여 IP 망 기반의 방송 서비스를 위한 효율적인 EPG 데이터 전송 방안을 제안한다. EPG 정보를 사용자 요구 특성을 고려하여 여러 그룹으로 분할하고 이에 대해 OOB 채널을 통한 멀티캐스트 전송 방식과 사용자 별 요구 및 응답 처리를 통한 유니캐스트 전송 방식을 혼합 적용한다. 또한 서비스 요구 상황에 따라 두 방식을 동적으로 선택 및 변경함으로써 EPG 시스템의 서버 자원과 네트워크 대역폭을 효율적으로 활용할 수 있다.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1992.11a
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• pp.165-179
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• 1992

영지식 대화증명은 인증자(prover)가 비밀정보를 노출시키지 않으면서, 검증자(verifier)와 대화를 통해서 이 비밀정보를 알고 있음을 검증자에게 증명하는 방법이다. 본 논문에서는 ElGamal 암호 알고리듬을 이용하여 메세지 전송과 개인 인중이 동시에 가능한 순방향 영지식 증명 프로토콜과 역방향 영지식 증명 프로토콜을 제안한다. 그리고 전송효율을 송신한 전비트와 정보비트와의 비로 정의하여 각각의 프로토콜의 전송효율을 계산한다.

• Journal of Broadcast Engineering
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• v.16 no.5
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• pp.811-823
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• 2011

This paper proposes an efficient transmission method for the panoramic multimedia contents. The panoramic video provides wide sight and various view-point to the user. The traditional methods of the panoramic multimedia content transmission has several limitations, as follow; A client suffers a long initial delay time to play a panoramic video when it is transmitted through a limited bandwidth network, because the panoramic video has larger data size than a general video. And if a client's display device has limited resolution, such as mobile phone, laptop PC monitor, etc. it can not display the entire panoramic video that has a wide view video sequence. So, in order to overcome the obstacles, this paper proposes an efficient transmission of panoramic multimedia contents. This method will increase the transmission efficiency throughout the technique of the scene description in MPEG-4 system. Also we demonstrated the efficiency of the proposed method by comparison with existing methods.

• Journal of Internet Computing and Services
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• v.8 no.2
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• pp.43-54
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• 2007

The effective power consumption is the primary issue in a sensor network which consists of the sensor nodes with limited battery power. So, most of the MAC protocols in sensor networks have been designed with the consideration of energy efficiency. Generally, these protocols make use of the listen and sleep mode periodically. However, this approach inevitably causes a long transmission delay on the data forwarding path, which is mainly resulted from the sleep time of the receiver node. This paper deals with a design of DT-MAC(Data Transmission centric MAC) protocol, with minimizes the data transmission delay while it forces each node to consume its energy efficiently. Thus, a node received a packet converts its remained sleep time to the pseudo_listen time, in which the node is able to transmit a packet. With benefit of the pseudo_listen period, the data transmission delay along with the data forwarding path will be shortened as much as it possible. Therefore, DT-MAC protocol is very suitable to the various applications which require a real time sensing data such as disaster and fire alarm.

• Journal of the Institute of Convergence Signal Processing
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• v.20 no.2
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• pp.111-117
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• 2019

We investigated the variations in the magnetic-field distribution and power transmission efficiency, resulting from changes in the relative positions of the transmitting and receiving coils, for electromagnetic-induction-type wireless power transmission using an elliptical receive coil. Results of simulations using a high-frequency structure simulator were compared to actual measurement results. The simulations showed that the transmission efficiency could be maintained relatively stable even if the alignment between the transmitting and receiving coils was changed to some extent. When the centre of the receiving coil was perfectly aligned with the centre of the transmitting coil, the transmission efficiency was the maximum; however, the degree of decrease in the transmission efficiency was small even if the centre of the receiving coil moved by ± 10mm from the centre of the transmitting coil. Therefore, it is expected that the performance of the wireless power transmission system will not be degraded significantly even if perfect alignment is not maintained. The results suggested a standardized application method of wireless transmission in the utilization of wireless power for implantable sensors.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.4
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• pp.3-9
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• 2017

Due to difficulties of continuous electric power provision to underwater communication nodes, the efficient power usage is highly required in underwater network protocol. In this paper, we studied the energy efficient MAC(Medium Access Control) protocol for underwater network supporting mobile nodes such as UUV(Unmanned Underwater Vehicle) and AUV(Autonomous Underwater Vehicle). The mobile nodes could waste the electric power in vain when the receiver moves out of the radio propagation coverage during the data exchange and thus the transmitted data fails in reaching the receiver. Expecially, such a failure is much more obvious in underwater acoustic channels since the propagation delay is about $10^5$ times slower than in terrestrial radio channels. This proposed mobility-MAC controls the data dropping stochastically in the Dropping Zone by considering the receiver's location and moving velocity. In conclusion, this selective dropping method not only improves latency and throughput by reducing invalid droppings but also boosts power efficiency by valid droppings.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.12B
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• pp.1076-1086
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• 2006

In providing video-on-demand (VoD) services to a number of clients through networks, the bandwidth requirements of video transmission restrict VoD services. For this reason, many significant broadcasting-based VoD schemes have been proposed to efficiently support services. However, the broadcasting-based VoD schemes approach needs frequency channel hopping, using many channels at the same time and managing many segments of a video. These make it difficult to implement. In this paper, we propose a Harmonic Staggered broadcasting scheme which has a simple structure and substantially improved VoD efficiency. The numerical results demonstrate that the viewer's waiting time of the Harmonic Staggered broadcasting scheme is close to the harmonic broadcasting scheme and the maximum buffer requirements of this can be adapted for demanding rate by adjusting the short front part of a video sizes.

• Journal of Korea Spatial Information System Society
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• v.12 no.1
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• pp.10-17
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• 2010

Sensor nodes used in Geosensor network are resource limited and power constrained. So it is necessary to research on routing protocols to gather data by using energy efficiently. Wireless sensor networks collect data gathered from sensor nodes by transfering it to the sink using multihop. However, it has two problems. First, the existing works require unnecessary data transmission for choosing a proper parent node to transfer data. Secondly, they have a large number of data transmission because each sensor node has a different path. To solves the problems, we, in this paper, propose a designated path based data aggregation scheme for efficient energy management in WSNs. The proposed scheme can reduce unnecessary data transmission by pre-determining a set of paths and can enable all the sensor nodes to participate in gathering data by running them in round-robin fashion. We show from performance analysis that the proposed scheme is more energy efficient than the existing directed diffusion(DD) and the hierarchical data aggregation(HDA).

• Journal of Internet Computing and Services
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• v.9 no.5
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• pp.131-140
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• 2008

In this paper, we present a data dissemination protocol that guarantees energy-efficient data transmission and maximizes network lifetime. SPMS that outperforms the well-known protocol SPIN uses the shortest path to minimize the energy consumption. However, since it repeatedly uses the same path, maximizing the network lifetime is impossible. In this paper, we propose a protocol for data dissemination called the protocol Considering Between Energy and Distance (ConBED). It solves the network lifetime problem using the residual energy and the distance between nodes to determine a path for data dissemination. The simulation results show that ConBED guarantees energy-efficient transmission and increases the network lifetime by approximately 69% than that of SPMS.