• Journal of Korea Game Society
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• v.11 no.1
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• pp.131-138
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• 2011

Recently in terrain rendeing, most researches introduce mipmap-based out-of-core methods for handling large sized DEM data which does not fit in main memory of general computer. However, mipmap-based LOD(level-of-detail) methods occur geometric errors which appear in data simplifying the higher LOD level. These geometric errors cause geometric popping effects where LOD level changes when viewpoint moves. In this paper, we propose vertex cohesion map for reducing geometric error. In preprocessing step, we generate vertex cohesion map, which is a texture that stores the vectors. By these vectors, each vertex will be cohered into the position in which the difference of gradient value is bigger than others. Therefore in terrain rendering, using vertex cohesion map can dramatically reduce the geometry popping effects rather than using mipmap.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.9A
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• pp.1442-1450
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• 1999

In this paper, we present an efficient hardware architecture for the frame memory of the MPEG-2 video encoder. Both the total size of internal buffers and the number of logic gates are reduced by the proposed memory map which can provide an effective interface between MPEG-2 video encoder and the external DRAM. Furthermore, the proposed scheme can reduce the DRAM access time. To realize the frame memory hardware,$0.5\mu\textrm{m}$, VTI, vemn5a3 standard cell library is used. VHDL simulator and logic synthesis tool are used for hardware design and RTL (register transfer level) function verification. The frame memory hardware emulator of the proposed architecture is designed for gate-level function verification. It is expected that the proposed frame memory hardware using VHDL can achieve suitable performance for MPEG-2 MP@ML.

• The KIPS Transactions:PartD
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• v.16D no.6
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• pp.845-850
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• 2009

Use of XML data has been increased with growth of Web 2.0 environment. XML is recognized its advantages by using based technology of RSS or ATOM for transferring information from blogs and news feed. Bitmap clustering is a method to keep index in main memory based on Relational DBMS, and which performed better than the other XML indexing methods during the evaluation. Existing method generates too many clusters, and it causes deterioration of result of searching quality. This paper proposes k-Bitmap clustering method that can generate user defined k clusters to solve above-mentioned problem. The proposed method also keeps additional inverted index for searching excluded terms from representative bits of k-Bitmap. We performed evaluation and the result shows that the users can control the number of clusters. Also our method has high recall value in single term search, and it guarantees the searching result includes all related documents for its query with keeping two indices.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.135-141
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• 2012

To reduce frame memory size usage in LCD overdrive, block truncation coding (BTC) image compression is commonly used. For maximization of compression ratio, BTC image compression is need to compress bitmap or quantization data. In this paper, for high compression ratio, we propose CMBQ-BTC (CMBQ : compression method bitmap data and quantization data) algorithm. Experimental results show that proposed algorithm is efficient as compared with PSNR and compression ratio of the conventional BTC method.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.05a
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• pp.19-22
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• 2005

XML은 비즈니스 메시징, 웹사이트 정보 통합, 그리고 카탈로그 통합 등의 분야에서 다양한 데이터를 표현하기 위한 포맷으로 급격하게 성장했다. 그러나 XML 데이터의 형태가 고정되어 있지 않기 때문에 전통적인 질의 방법이 항상 정확한 결과를 보여주지는 않는다. 또한 객체 지향 DBMS가 이 영역에 적합한지의 여부는 아직 명확하지 않다. 따라서 XML 데이터를 효율적으로 검색하기 위해 기존의 관계형 DBMS와 연계하여 구조 유사성을 기반으로 하는 검색 기법이 연구되고 있다. 그 중 문서, 경로, 단어로 구성된 3차원 비트맵 인덱스를 이용한 검색 시스템은 다른 XML 문서 검색 시스템보다 훨씬 빠른 수행 속도를 보여주지만, 3차원의 메모리 구조를 사용하여 많은 저장공간을 필요로 하는 단점이 있다. 본 논문에서는 XML 문서를 저장할 때 경로들 사이의 유사성을 이용하여 XML 데이터의 경로를 통합하는 기법에 대해 소개한다. 이렇게 통합된 경로를 이용하여 생성하는 3차원 비트맵 인덱스는 그 크기가 상당히 줄어들게 되고, 기존의 연구에서 보여주었던 문제점들을 해결하게 되었다.

• Journal of KIISE
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• v.42 no.3
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• pp.307-319
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• 2015

Current ontology studies use the Hadoop distributed storage framework to perform map-reduce algorithm-based reasoning for scalable ontologies. In this paper, however, we propose a novel approach for scalable Web Ontology Language (OWL) Horst Lite ontology reasoning, based on distributed cluster memories. Rule-based reasoning, which is frequently used for scalable ontologies, iteratively executes triple-format ontology rules, until the inferred data no longer exists. Therefore, when the scalable ontology reasoning is performed on computer hard drives, the ontology reasoner suffers from performance limitations. In order to overcome this drawback, we propose an approach that loads the ontologies into distributed cluster memories, using Spark (a memory-based distributed computing framework), which executes the ontology reasoning. In order to implement an appropriate OWL Horst Lite ontology reasoning system on Spark, our method divides the scalable ontologies into blocks, loads each block into the cluster nodes, and subsequently handles the data in the distributed memories. We used the Lehigh University Benchmark, which is used to evaluate ontology inference and search speed, to experimentally evaluate the methods suggested in this paper, which we applied to LUBM8000 (1.1 billion triples, 155 gigabytes). When compared with WebPIE, a representative mapreduce algorithm-based scalable ontology reasoner, the proposed approach showed a throughput improvement of 320% (62k/s) over WebPIE (19k/s).

• Journal of Digital Contents Society
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• v.11 no.1
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• pp.91-97
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• 2010

Flash memory has been used by many digital devices for data storage, exploiting the advantages of non-volatility, low power, stability, and so on, with the help of high integrity, large capacity, and low price. As the fast growing popularity of flash memory, the density of it increases so significantly that its entire address mapping table becomes too big to be stored in SRAM. This paper proposes the associated page address cache with an efficient table management scheme for hybrid flash translation layer mapping. For this purpose, all tables are integrated into a map block containing entire physical page tables. Simulation results show that the proposed scheme can save the extra memory areas and decrease the searching time with less 2.5% of miss ratio on PC workload and can decrease the write overhead by performing write operation 33% out of total writes requested.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06d
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• pp.46-48
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• 2006

현재 컴퓨터에서 사용되는 수의 체계는 컴퓨터의 메모리구조에서 사용하기 가장 알맞은 2진법과16진법이며 여러 프로그램들에서 효율적으로 사용되어 왔다. 그러나 어떠한 수의 체계든지 프로그램의 성질에 따라 예외적으로 드러나는 비효율적인 특성을 가지고 있다. 본 논문에서, 우리는 라우팅 관점에서의 2진법과 16진법의 예외적인 부분을 이용한 새로운 라우팅 어드레스의 표기법을 제안하며, 제안된 어드레스의 표기법을 이용한 라우팅 테이블과 라우팅 어드레스맵을 구성, 최소한의 메모리를 사용하여 센서네트워크 상에서 효율적인 Ad-Hoc 양방향 라우팅 방식을 구현하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06a
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• pp.176-178
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• 2012

낸드 플래시 메모리는 FTL의 페이지 re-mapping 동작으로 인하여 특정 페이지가 무효화되었음에도 불구하고 물리적으로 소거되지 않은 상태로 낸드 플래시 공간을 점유하는 문제가 발생할 수 있다. 플래시 저장장치의 제어기는 플래시 기반 저장장치의 지속적인 쓰기 성능 유지와 저장 용량 확보를 위해 무효 페이지를 물리적으로 제거하고 유효 페이지를 수집하는 가비지 컬렉션 연산을 수행한다. 따라서 다수의 블록을 대상으로 가비지 컬렉션 연산을 수행할 경우, 많은 페이지 복사와 블록 삭제 연산들로 인한 저장장치 지연현상이 발생할 수 있다. 본 논문에서는 낸드 플래시 저장장치에 적용 가능한 효과적인 가비지 컬렉션 메커니즘을 제안한다. 선점방식 가비지 컬렉션 기법은 블록 맵의 데이터 구조를 간단히 수정하여, 단일 블록을 대상으로 가비지 컬렉션을 수행한다. 이 기법의 유효성은 페이지 복사와 블록 삭제 연산을 세부 단위로 분할하여 처리가 가능하므로 가비지 컬렉션이 수행되는 도중에 요청되는 호스트의 요청에 기민하게 응답가능하다는 것이다.

• Journal of Internet Computing and Services
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• v.3 no.6
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• pp.35-41
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• 2002

The Car Navigation System(CNS) requires lots of memory and calculating time because it works on the large and complex digital map. And the traffic circumstances vary time by time, so the traffic informations should be processed if we want to get mere realistic result. This paper proposes an effective path searching algorithm which uses less memories and calculating time by applying directional information between the starting place and destination place and by using realtime traffic informations.