• 제목/요약/키워드: prefix expansion

검색결과 6건 처리시간 0.024초

A Hybrid Prefix Cashing Scheme for Efficient IP Address Lookup

  • Kim, Jinsoo;Kim, Junghwan
    • 한국컴퓨터정보학회논문지
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    • 제20권12호
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    • pp.45-52
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    • 2015
  • We propose a hybrid prefix caching scheme to enable high speed IP address lookup. All prefixes loaded in a prefix cache should not be overlapped in address range for correct IP lookup. So, every non-leaf prefix needs to be expanded not so as to be overlapped. The shorter expanded prefix is more preferable because it can cover wider address range just as an single entry in a prefix cache. We exploits advantages of two dynamic prefix expansion techniques, bounded prefix expansion technique and bitmap-based prefix expansion technique. The proposed scheme uses dual bound values whereas just one bound value is used in bounded prefix expansion. Our elaborated technique make the dual bound values be associated with several subtries flexibly using bitmap information, rather than with fixed subtries. We evaluate the performance of the proposed scheme in terms of the average length of the expanded prefixes and cache miss ratio. The experiment results show the proposed scheme has lower cache miss ratio than other previous schemes including both bounded prefix expansion and bitmap-based expansion irrespective of the cache size.

Bitmap-based Prefix Caching for Fast IP Lookup

  • Kim, Jinsoo;Ko, Myeong-Cheol;Nam, Junghyun;Kim, Junghwan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제8권3호
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    • pp.873-889
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    • 2014
  • IP address lookup is very crucial in performance of routers. Several works have been done on prefix caching to enhance the performance of IP address lookup. Since a prefix represents a range of IP addresses, a prefix cache shows better performance than an IP address cache. However, not every prefix is cacheable in itself. In a prefix cache it causes false hit to cache a non-leaf prefix because there is possibly the longer matching prefix in the routing table. Prefix expansion techniques such as complete prefix tree expansion (CPTE) make it possible to cache the non-leaf prefixes as the expanded forms, but it is hard to manage the expanded prefixes. The expanded prefixes sometimes incur a great deal of update overhead in a routing table. We propose a bitmap-based prefix cache (BMCache) to provide low update overhead as well as low cache miss ratio. The proposed scheme does not have any expanded prefixes in the routing table, but it can expand a non-leaf prefix using a bitmap on caching time. The trace-driven simulation shows that BMCache has very low miss ratio in spite of its low update overhead compared to other schemes.

IP 주소 검색에서 블룸 필터를 사용한 다중 해싱 구조 (Multiple Hashing Architecture using Bloom Filter for IP Address Lookup)

  • 박경혜;임혜숙
    • 한국정보과학회논문지:데이타베이스
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    • 제36권2호
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    • pp.84-98
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    • 2009
  • 라우터의 포워팅 성능을 향상시키기 위해 많은 IP 주소 검색 알고리즘들이 연구되어 오고 있다. 기존에 제안된 블룸 필터를 이용한 IP 주소 검색 구조는 프리픽스 길이별로 블룸 필터 및 해시 테이블을 따로 가지고 있어 구현이 복잡하며, 프리픽스 길이 별 해시 테이블의 개수를 줄이기 위하여 프리적스의 복사가 불가피한 단점을 지닌다. 멀티 다중 해시 테이블을 이용한 병렬 해싱 구조는 프리픽스의 길이별로 해시 테이블을 구성하고, 다중 해싱 함수를 사용하여 모든 프리픽스 길이에 대하여 병렬 검색하는 구조로서 검색 성능이 뛰어나나 병렬 검색 구조이므로 구현이 또한 복잡하다. 본 논문에서는 단일 블룸 필터에 다양한 길이의 프리픽스를 모두 저장하는 통합 블룸 필터와 단일 테이블에 모든 길이의 프리픽스를 모두 저장하는 통합 다중-해시 테이블을 사용하여 구현이 간단하면서도 검색성능이 뛰어난 새로운 IP 주소 검색 구조를 제안한다. 실제 백본 라우터에서 쓰이는 데이타를 이용하여 시뮬레이션을 수행한 결과 $15000{\sim}220000$개의 엔트리를 갖는 라우팅 테이블에 대하여 평균 1.04-1.17번의 메모리 접근으로 IP 주소검색이 가능함을 보였다.

K콘텐츠에서 K푸드 표상 양상과 효과 (Representational aspects and effects of K-food in K-content)

  • 유재응;이현경
    • 문화기술의 융합
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    • 제10권1호
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    • pp.165-170
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    • 2024
  • 'K콘텐츠'가 글로벌하게 각광받고 있다. 'K'라는 접두어가 유행하면서 K푸드에 대한 관심도 높아졌다. K콘텐츠에 대한 다양한 연구가 이루어지고 있지만, K푸드에 대한 연구는 아직 일천하다. K푸드에 대한 언급이나 기사 등은 주로 국내 브랜드의 해외 진출, 마케팅 현황, 매출에 국한되어 있고, 소수의 연구논문도 특정 브랜드의 해외 진출사례를 다루고 있을 뿐이다. 본고는 국내에서 제작된 예능과 드라마 프로그램에서 K푸드가 어떤 방식으로 표상되고 있으며 그 효과가 무엇인지 실증적인 작품을 통해 분석하고자 한다. 음식을 소재로 한 예능 프로그램 중 K콘텐츠로서 경쟁력이 갖고 있는 것은 외국인의 한식 체험을 다룬 것으로 보인다. 여기에는 한국을 방문한 외국인이 한국 문화체험의 일환으로 한식을 경험하는 방식이나 해외에 나가 일시적으로 식당을 차려 현지인들에게 한식을 판매하는 유형이 대표적이다. 그런데 이런 예능의 문제점은 '국뽕' 정서를 바탕으로 하고 있기 때문에 장기적인 소구력은 부족하다는 것이다. K콘텐츠 속 K푸드의 노출은 엄청난 광고 효과를 창출한다. K푸드를 소재로 한 K콘텐츠의 현황과 분석은 향후 프로그램 제작의 방향과 K푸드의 정체성 확립에 도움을 줄 수 있다고 판단된다.

패킷 필터링 시스템에서 범위 규칙의 효율적 TCAM 엔트리 변환 알고리즘 연구 (A Study on the Efficient Algorithm for Converting Range Matching Rules into TCAM Entries in the Packet Filtering System)

  • 김용권;조현묵;최진규;이규호;기장근
    • 전기전자학회논문지
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    • 제9권1호
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    • pp.19-30
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    • 2005
  • 패킷 분류란 규정된 규칙과 입력된 패킷의 헤더 필드를 검색하여 매칭 여부를 판단하는 것으로 하드웨어적인 패킷 필터링 시스템은 일반적으로 Ternary Content Addressable Memory를 사용하여 구현된다. 하지만 TCAM은 구조적인 특성으로 인해 범위 규칙을 효율적으로 분류할 수 없기 때문에 기존의 필터링 시스템에서는 주어진 범위를 대표할 수 있는 prefix 형태의 값으로 범위를 변환하고 변환된 값을 TCAM 엔트리에 저장하여 패킷 필터링 을 수행하며, 이 경우 범위 규칙의 필드가 W비트일 때 최대 2W-2 개의 엔트리가 필요하다 범위 규칙이 일반적으로 패킷 헤더 필드 중 소스포트와 목적지포드 필드에 사용되는 것을 고려하면 하나의 규칙이 최대 900개의 엔트리를 점유하게 된다. 본 논문에서는 범위 규칙을 TCAM 엔트리로 변환시 점유 엔트리 수를 줄이기 위해 범위 규칙을 대칭성을 가지는 그레이 코드로 변환한 후 범위를 대표할 수 있는 TCAM 엔트리로 변환하는 알고리즘을 제시하였다. 제안된 알고리즘은 최대 2W-4 개의 TCAM 엔트리로 변환되며, 모든 범위에 대해 기존의 방법 보다 항상 더 적은 수의 TCAM 엔트리를 생성한다 또한 negation 범위에 대해서도 효율적으로 적용 할 수 있다. 시뮬레이션 결과 16 비트의 범위 매칭에 대해 기존의 방법보다 제안된 알고리즘이 평균 7%의 TCAM 엔트리를 감소시킬 수 있으며, 패킷의 소스와 목적지 포트를 동시에 고려하는 경우 평균 14%를 절감할 수 있고, 실제 사용되고 있는 침입탐지 프로그램의 범위 규칙에 적용시킨 결과 10% 정도의 TCAM 엔트리를 절약할 수 있음을 보였다.

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현대회화에서의 형태와 물질 -Digital Transfiguration에 관한 연구- (Digital painting: Image transfonnation, simulation, heterologie and transfonnation)

  • 정숙영
    • 조형예술학연구
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    • 제10권
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    • pp.161-181
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    • 2006
  • The words which appeared in my theoretical study and work are image transformation to digital painting, simulation, heterologie and transfiguration, etc. Firstly, let's look into 'digital era' or 'new media era'. Nowadays, the image world including painting within the rapid social and cultural change, which is called as digital era, is having the dramatic change. Together with the development of scientific technology, large number of events which was deemed to be impossible is happening as real in image world Moreover, these changes in image world is greatly influencing to our life. The word which compresses this change of image world and shows is 'digital'. Digit, which means fingers in Latin, indicates separately changing signal, and to be more narrow, it indicates the continual signal of '0' and ' 1' in computer. The opposite word is 'analogue'. As analogue is the word meaning 'infer' or 'similarity', it indicates the signal or form which continuously changes along the series of time when it is compared to digital. Instead of analogue, digital is embossed as a major ruler along the whole area of our current culture. In whole culture and art area, and in whole generalscience, digital is appearing as it has the modernism and importance. The prefix, 'digital', e.g. digital media, digital culture, digital design, digital philosophy, etc, is treated as the synonym of modernism and something new. This advent of digital results the innovative change to the image world, creates the new beauty experience which we could not experience before, and forecasts the formation of advanced art and expansion of creative area. Various intellectual activities using computer is developing the whole world with making the infrastructure. Computer in painting work immediately accomplishes the idea of painters, takes part in simulation work, contingency such as abrupt reversal, extraction, twisting, shaking, obscureness, overlapping, etc, and timing to stimulate the creativity of painters, and provides digital formative language which enables new visual experience to the audience. When the change of digital era, the image appeared in my work is shown in 'transfiguration' like drawing. The word, 'transfiguration' does not indicate the completed and fixed real substance but indicate endlessly moving and floating shape. Thus, this concept is opposite to the substantial consideration, so that various concepts which is able to replace this in accordance with the similar cases are also exist such as change, deterioration, mutation, deformity of appearance and morphing which is frequently used in computer as a technical word. These concepts are not clearly classified, and variably and complicatedly related. Transfiguration basically means the denial of "objectivity' and '(continual) stagnation' or deviation from those. This phenomenon is appeared through the all art schools of art ever since the realism is denied in the 19th century. It is called as 'deformation' in case of expressionism, futurism, cubism, etc, in the beginning of the century, which its former indication is mostly preserved within the process of structural deviation and which has the realistic limit which should be preserved. On the contrary, dramatic transfiguration which has been showing in the modern era through surrealism is different in the point that dramatic transfiguration tends to show the deterioration and deviation rather than the preservation of indicated object. From this point, transfiguration coming out from morphing using computer deteriorates and hides the reality and furthermore, it replaces the 'reality'. Moreover, transfiguration is closely approached to the world of fake or 'imaginary' simulation world of Baudrillard. According to Baudrillard, the image hides and deteriorates the reality, and furthermore, expresses 'not existing' to 'imaginary' under the name of transfiguration. Certain reality, that is, image which is absent from the reality is created and overflowed, so that it finally replaces the reality. This is simulation as it is said by Baudrillard. In turn, Georges Bataille discusses about the image which is produced by digital technology in terms of heterologie. Image of heterologie is the visual signal which is established with the media. Image of media is to have the continuous characteristics of produce, extinction, and transformation, and its clear boundary between images becomes meaningless. The meaning of composition, excess, violation, etc of digital image is explained to heterological study or heteologie suggested as important meaning of Georges Bataille who is a heretic philosopher. As the form and image of mutation shows the shape in accordance with mechanical production, heterologie is introduced as very low materialism (or bas materialisme), in this theory. Heterologie as low materialism which is gradually changing is developing as a different concept and analysis because of the change of time in the late 20s century beside high or low meaning. Including my image, all images non-standardizes and transforms the code. However, reappearance and non-standardization of this code does not seem to be simple. The problem of transformation caused by transfiguration which appears in my digital drawing painting, simulation, heterologie, etc, are the continual problems. Moreover, the subject such as existence of human being, distance from the real life, politics and social problems are being extended to actual research and various expressing work. Especially, individual image world is established by digital painting transfiguration technique, and its change and review start to have the durability. The consciousness of observers who look at the image is changing the subject. Together with theoretical research, researchers are to establish the first step to approach to various image change of digital era painting through transfiguration technique using our realistic and historical image.

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