• Title/Summary/Keyword: 무선 방송

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Broadcast Method based on Data Access Frequencies and Semantic Relationships in Mobile Computing Environments (이동컴퓨팅 환경에서 데이타의 접근빈도 및 시맨틱 관계를 고려한 방송 방법)

  • 최성환;정성원;이송이
    • Journal of KIISE:Databases
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    • v.30 no.5
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    • pp.476-493
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    • 2003
  • Data broadcast is an effective data transmission method from a data base server to numerous mobile clients due to the restrictions on mobile environment such as low wireless communication bandwidth and energy shortage of mobile devices. There are various broadcast methods based on clients' data access frequencies or semantic relationship of data. The broadcast schedule based only on the access frequencies does not consider semantic relations of data, so that when a client needs to access a series of semantically related data, the client has to listen to the wireless channel for a long time. On the other hand, the broadcast schedule based only on semantic relationship of data makes data access time longer when clients highly request specific data which are not semantically related but frequently accessed. In this paper, we present an efficient data broadcast method based on not only data access frequencies but also semantic relationship to improve mobile clients' query response time. The new hybrid broadcast method we propose creates a data broadcast schedule according to the data access frequencies and then the schedule is adjusted to reflect semantic relationship of data. We show our method is efficient by experimental performance analysis.

Data Allocation for Multiple Broadcast Channels (다중 방송채널을 위한 데이타 할당)

  • Jung Sungwon;Nam Seunghoon;Jeong Horyun;Lee Wontaek
    • Journal of KIISE:Databases
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    • v.33 no.1
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    • pp.86-101
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    • 2006
  • The bandwidth of channel and the power of the mobile devices are limited on a wireless environment. In this case, data broadcast has become an excellent technique for efficient data dissemination. A significant amount of researches have been done on generating an efficient broadcast program of a set of data items with different access frequencies over multiple wireless broadcast channels as well as single wireless broadcast channel. In this paper, an efficient data allocation method over multiple wireless broadcasting channels is explored. In the traditional approaches, a set of data items are partitioned into a number of channel based on their access probabilities. However, these approaches ignore a variation of access probabilities of data items allocated in each channel. In practice, it is difficult to have many broadcast channels and thus each channel need to broadcast many data items. Therefore, if a set of data items broadcast in each channel have different repetition frequencies based on their access frequencies, it will give much better performance than the traditional approaches. In this paper, we propose an adaptive data allocation technique based on data access probabilities over multiple broadcast channels. Our proposed technique allows the adaptation of repetition frequency of each data item within each channel by taking its access probabilities into at count.

Study of Local Area Weather Condition Monitoring System in WSN (WSN기반의 국지적 기상모니터링 시스템 고찰)

  • Chung, Wan-Young;Jung, Sang-Joong;Kim, Jong-Jin;Kwon, Tae-Ha
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.05a
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    • pp.271-276
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    • 2009
  • An local area weather condition monitoring system to minimize many disasters from the sudden change of weather condition in local and mountain area is proposed. Firstly, the comparison of present state of the related monitoring systems and the possibility of realization with some merits are investigated. Moreover, this paper present direction of local area weather condition monitoring system based on integration of wireless sensor network and CDMA network following some case study. Through the efficient integration of both networks, the measured weather condition data from sensors can be transmitted to the server or mobile to monitor with high reliability. The proposed monitoring system will guide new type of project in wireless sensor network and support alarm service of the sudden change of weather condition to mobile user from central official regulations.

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The Hague Convention on Jurisdiction and Enforcement, of Judgments

  • Park, Yu-Sun
    • Journal of Arbitration Studies
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    • v.16 no.1
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    • pp.343-373
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    • 2006
  • 지적재산권의 속지주의 원칙에 따라 전통적으로 지적재산권의 침해에 있어서 결과의 발생이 없는 행위지를 침해지로 인정하지 않았다. 어문과 예술작품을 보호하기 위해 1886년 체결된 베른협약(Berne Convention for the Protection of Literary and Artistic Works) 제5조 제1항은 저작자가 베른협약에 따라 보호되는 저작물에 관하여 본국 이외의 동맹국에서 각 법률이 현재 또는 장래에 자국민에게 부여하는 권리 및 이 협약이 특별히 부여하는 권리를 향유한다고 규정하여 내국민대우원칙을 천명하고 있다. 또한 베른협약 제5조 제2항은 저작권의 보호와 향유는 저작물의 본국에서 보호가 존재하는 여부와 관계가 없이, 보호의 범위와 저작자의 권리를 보호하기 위하여 주어지는 구제의 방법은 오로지 보호가 주장되는 국가의 법률의 지배를 받는다라고 규정하여 저작권 침해가 발행한 국가의 법률의 적용을 명시하고 있다. 인터넷과 무선통신 기술의 발달은 저작물을 디지탈 형식으로 실시간에 전세계에 배포하는 것을 가능하게 하였다. 특히 저작물의 인터넷상에서의 배포는 다국적 저작권 침해행위를 야기하여, 저작권자가 다수의 국가에서 저작권 침해소송을 제기하여 판결을 집행하는 것이 필요하게 되었다. 헤이그국제사법회의(Hague Conference on Private International Law)에서 1992년부터 논의되어 온 민사 및 상사사건의 국제재판관할과 외국판결에 관한 협약(Convention on Jurisdiction and Foreign Judgment in Civil and Commercial Matters)에서 채택된1999년의 예비초안(preliminary draft) 및 2001년 외교회의에서 수정된 잠정초안(Interim text) (이하 헤이그 협약 )은 저작권자가 저작권침해행위가 발생한 각 국가에서 저작권 침해행위를 금지하는 소송을 제기할 필요없이, 동 협약의 한 가맹국가의 법원의 저작권침해금지판결을 다른 가맹국가에서도 집행할 수 있는 가능성을 제시해 주는데 의미가 있다. 헤이그 협약 제10조는 불법행위(torts)에 관한 일반적인 재판관할에 관한 규정을 두고 있으며, 저작권침해에 관한 분쟁은 동 조항의 적용을 받는다. 제10조에 의해 당사자는 가해행위지 국가의 법원 또는 결과발생지 국가의 법원에서 소송을 제기할 수 있다. 결과발생지의 경우 제10조 1항 (b)는 피고가 자신의 행위가 본국의 법규에 비추어 동일한 성격의 손해를 초래할 수 있다라고 합리적으로 예견할 수 없었던 경우에 본 조항의 적용을 배제하고 있다. 인터넷을 통한 저작권침해의 경우, 피고가 자신의 국가의 법규하에서 합법적으로 저작물을 웹사이트에 게시하였으나, 그 행위가 다운로딩이 행해진 국가에서 불법인 경우, 피고는 저작권침해를 예견할 수 없었으므로 이에 문제가 제기된다. iCrave TV사건에서, 피고인 캐나다회사가 미국 및 캐나다에서 방송되는 텔레비젼 방송 프로그램을 자신의 웹사이트에 게시하여 이용자들로 하여금 컴퓨터를 통하여 방송을 재시청 할 수 있도록 하였는데 이는 캐나다에서 합법인 반면에 미국에서는 저작권 침해에 해당한다. 피고는 방송 프로그램을 인터넷상에서 재방송하는 것은 캐나다법상 합법이므로 저작권침해를 예견할 수 없었다고 주장하면서, 해당 사이트에 오직 캐나다 거주자만의 접속을 허용하고 미국 거주자의 접속을 제한하는 일련의 Click-Wrap 계약과 스크린 장치를 제공하였다고 주장하였다. 본 사건 피고의 주장을 받아들인다고 가정할 때, 제10조 1항(b)에 의해 원고는 결과발생지인 미국법원의 재판관할을 강제할 수 없을 것이다. 지적재산권을 둘러싼 분쟁에 관한 재판관할과 국제법상의 판결의 승인 및 집행의 통일성을 기하기 위하여 2001년 1월 세계지적재산권기구(World Intellectual Property Organization)가 제안한 WIPO 협약초안(Draft Convention on Jurisdiction and Recognition of Judgments in Intellectual Property Matters)은 헤이그 협약이 재판관할과 판결의 승인 및 집행에 대한 일반적인 접근을 하고 있는 점에 반하여 지적재산권자의 보호라는 측면을 고려하여 지적재산권침해소송에 국제재판관할권을 규정하고 있다. WIPO 협약초안 제6조는 저작권자가 저작권 침해를 막기 위한 합리적인 조치를 취한 국가에서 저작권 침해소송을 피할 수 있다고 규정하고 있다. 따라서 본 조항에 의할 경우, iCrave TV사건의 피고는 미국에서의 저작권 침해소송을 회피할 수 있을 것이다. 이상과 같이 헤이그 협약이 외국판결의 승인 및 집행을 가능하게 하고 있음에도 불구하고, 외국법원의 판결이 다수의 가맹국가에서 집행되지 못하는 가장 큰 장애는 대다수의 국가들이 외국법원의 판결이 공서양속(Public Policy)에 반하는 경우 판결을 승인하지 않는 예외규정을 두고 있기 때문이다. 미국의 경우, Uniform Recognition Act와 Restatement(Third) of Foreign Relations에 따른 공서양속의 예외규정(Public Policy exception)은 외국법원의 판결의 승인을 부인하는 근거가 된다. Yahoo! 사건에서 Yahoo! Inc.의 옥션 사이트를 통해 독일 나치 소장물의 판매가 이루어졌는데, 프랑스 형법상 이는 범죄행위에 해당하므로, 프랑스 법원은Yahoo! Inc.에게 프랑스 이용자가 당해 옥션 사이트에 접속할 수 없도록 모든 가능한 조치를 취할 것을 명하였다. 이에 미국 법원은 프랑스 법원의 판결은 Yahoo! Inc.의 미국헌법 제1 수정(First Amendment)의 언론의 자유(freedom of speech)에 반하므로 판결의 집행을 거부하였는데 이는 공서양속의 예외규정을 보여주는 예이다. 헤이그 협약 제28조와 WIPO 협약초안 제25조 또한 공서양속의 예외규정을 두고 있다. 본 논문은 인터넷과 통신기술의 발달로 야기되는 다국적 저작권 침해사건에서 한 국가의 법원의 저작권 침해금지판결이 다수의 국가에서 승인 및 집행될 수 있는 능성을 헤이그 협약과 WIPO 협약초안 및 미국판결을 중심으로 살펴보았다. 국제적으로 통일된 저작권법이 존재하지 않고 외국 판결의 승인을 부인하는 예외조항과 외국판결의 집행에 관한 각국의 이해관계와 준거법의 해석이 다른 현시점에서 지적재산권의 속지주의를 뛰어넘어 외국법원의 판결을 국제적으로 집행하는 것은 다소 어려움이 있어 보이나 국제적인 집행가능성의 열쇠를 제시하는 헤이그 협약과 장래의 국제조약에 그 기대를 걸어볼 수 있겠다.

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A Review Essay on Legal Mechanisms for Orbital Slot Allocation (정지궤도슬롯의 법적 배분기제에 관한 논고)

  • Jung, Joon-Sik;Hwang, Ho-Won
    • The Korean Journal of Air & Space Law and Policy
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    • v.29 no.1
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    • pp.199-236
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    • 2014
  • This paper analyses from the perspective of distributive justice the legal mechanisms for international allocation of orbital slots, which are of co-owned nature and thereby limited natural resources in outer space. The allocative function is delegated to the International Telecommunication Union. The Radio Regulation, amongst such other legal instruments as the Constitution and Convention, by which the ITU and contracting States thereof abides, dictates how the orbital positions are distributed. Thus, the RR is thoroughly reviewed in the essay. The mechanisms are in a broad sense categorized into two systems: 'a posteriori system' where the 'first come, first served' principle prevails; and 'a priori system' designed to foster the utilisation of the slots by those who lack space resources and are, in especial, likely to be marginalised under the former system. The argument proceeds on the premise that a posteriori system places the under-resourced States in unfavourable positions in the securement of the slots. In contrast with this notion, seven factors were instantiated for an assertion that the degradation of the distributive justice derived from the 'first come, first served' rule, which lays the foundation for the system, could be either mitigated or counterbalanced by the alleged exceptions to the rule. However, the author of this essay argues for counterevidences against the factors and thereby demonstrating that the principle still remains as an overwhelming doctrine, posing a threat to the pursuit of fair allocation. The elements he set forth are as in the following: 1) that the 'first come, first served' principle only applies to assignments capable of causing harmful interferences; 2) the interoperability of the principle with the 'rule of conformity' with the all the ITU instruments; 3) the viability of alternative registrations, as an exception of the application of the principle, on the condition of provisional and informational purposes; 4) another reference that matters in deciding the priority: the types of services in the TFA; 5) the Rule of Procedure H40 proclaiming a ban on taking advantage of coming first to the Register; 6) the technical factors and equity-oriented norms under international and municipal laws along with; 7) the changes of 'basic characteristics' of registered assignments. The second half of this essay illustrates by examining the relevant Annexes to the Regulation that the planned allocation, i.e., a priori system, bear the structured flaws that hinder the fulfillment of the original purpose of the system. The Broadcasting and Fixed Satellite Systems are the reviewed Plans in which the 'first come, first served' principle re-emerges in the end as a determining factor to grant the 'right to international recognition' to administrations including those who has not the allotted portions in the Plan.

An Efficient Cache Consistency Method for Mobile Clients in Wireless Environments (무선 환경에서의 이동 클라이언트를 위한 효율적인 캐시 일관성 유지 방안)

  • 송원민;정성원
    • Journal of KIISE:Databases
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    • v.30 no.6
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    • pp.606-628
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    • 2003
  • Recently, there have been many research efforts reported in the literature that focus on the cache consistency problems of mobile clients resulting from their frequent disconnections with a server in mobile environments. To cope with this problem, a number of methods based on the invalidation report scheme has been proposed. However, these proposed methods are sensitive to the disconnection time of mobile clients and independent of the frequency of data updates in the server. As a result, although the number of data updated in the server is small, the traditional methods can not guarantee the cache consistency of mobile clients if their disconnection time is over the time period the invalidation report is allowed to cover. In this paper, we propose an efficient cache consistency method called CCI(Cost-based Cache Invalidation) for mobile clients that take into account not only the disconnection time but also the frequencies of data updates in the server We also present an in-depth experimental analysis by comparing CCI method with BT(Broadcasting Time stamp) method based on Invalidation Report.

Architecture of an LDPC Decoder for DVB-S2 using reuse Technique of processing units and Memory Relocation (연산기와 메모리 재사용을 이용한 효율적인 DVB-S2 규격의 LDPC 복호기 구조)

  • Park Jae-Geun;Lee Chan-Ho
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.43 no.9 s.351
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    • pp.31-37
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    • 2006
  • Low-density parity-check (LDPC) codes are recently emerged due to its excellent performance. The standard for European high definition satellite digital video broadcast, DVB-S2 has adopted LDPC codes as a channel coding scheme. This paper proposes a DVB-S2 LDPC decoder architecture using a hybrid parity check matrix which is efficient in hardware implementation for both decoders and encoders. The hybrid H-matrices are constructed so that both the semi-random technique and the partly parallel structure can be applied to design encoders and decoders. Using the hybrid H-matrix scheme, the architecture of LDPC decoder for DVB-S2 can be very practical and efficient. In addition, we show a new Variable Node processor Unit (VNU) architecture to reuse the VNU for various code rates and optimized block memory placement to reuse. We design a DVB-S2 LDPC decoder of code rate 1/2 usng the proposed architecture. We estimate the performance of the DVB-S2 LDPC decoder and compare it with other decoders.

Design of an Efficient LDPC Codec for Hardware Implementation (하드웨어 구현에 적합한 효율적인 LDPC 코덱의 설계)

  • Lee Chan-Ho;Park Jae-Geun
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.43 no.7 s.349
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    • pp.50-57
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    • 2006
  • Low-density parity-check (LDPC) codes are recently emerged due to its excellent performance. However, the parity check (H) matrices of the previous works are not adequate for hardware implementation of encoders or decoders. This paper proposes a hybrid parity check matrix which is efficient in hardware implementation of both decoders and encoders. The hybrid H-matrices are constructed so that both the semi-random technique and the partly parallel structure can be applied to design encoders and decoders. Using the proposed methods, the implementation of encoders can become practical while keeping the hardware complexity of the partly parallel decoder structures. An encoder and a decoder are designed using Verilog-HDL and compared with the previous results.

Time Analysis of Structural Element and Theme Association of Television News Imagery (텔레비전 뉴스 영상의 구조적 요소와 주제연관성 시계열 분석)

  • Park, Dug-Chun
    • The Journal of the Korea Contents Association
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    • v.11 no.7
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    • pp.100-109
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    • 2011
  • This thesis is a content analysis on whether the proportion of structural element and theme association of television news imagery is different, depending on the historical background, and on what it means, which can be the index of scene-based and realistic report. Most researches of television news are horizontal studies of the same period, making light of vertical studies reflecting the change of age. Therefore, This study analyzed 729 items composed of 11,945 shots extracted from MBC Newsdesk from 1987, to 2007, the samples of which were extracted by systematic random sampling with five years' interval. This content analysis found out that there was high proportion of scene-based and realistic report such as 'sound-bite', 'event footage', 'direct matching' in the year 1987, 2007, and high proportion of 'corroboration shot', 'file footage', 'indirect reference', 'literal matching only' in the year 1997, which revealed the fact that reality-based report had not been faithfully accomplished in 1997.

Modeling & Performance Analysis of the MAC Protocol for VDL in the Aeronautical Mobile Communication System (항공이동통신 시스템에서 VDL을 위한 MAC 프로토콜 모델링 및 성능 분석)

  • Kim, Yong-Joong;Park, Hyo-Dal
    • Journal of Advanced Navigation Technology
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    • v.13 no.3
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    • pp.327-336
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    • 2009
  • This paper analysis the STDMA protocol in aviation wireless data communications and carry out the performance analysis with simulation. The STDMA protocol that is currently being used in VDL Mode-4 has TDMA system characteristics, which provides time-division into several slots per one frame. The results of modeled STDMA protocol's data channel analysis show approximate 0.7 channel throughput at the transmission probabilities 0.045, 0.2, and 0.3 in the aspects of channel throughput. The delay time are 2.32434sec, 2.0293sec, and 2.12128sec respectively. These results shows the good stability in spite of variable transmission probabilities. Consequently, it is expected that STDMA protocol would be used properly for domestic communication demands and supervision system improvement by means of applying this to point-to-point communication and data/location broadcasting as a fundamental technology in CNS/ATM.

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