• Proceedings of the Korean Information Science Society Conference
• /
• 1998.10c
• /
• pp.556-558
• /
• 1998

이미지 분석이나 데이터 베이스 인덱싱 또는 종이 문서를 전자 문서화 하는 문제는컴퓨터 비젼 응용분야에서 중요 관심사가 되어왔다. 이러한 문제들을 처리하기 위해서는 제일 먼저 이미지와 문자가 혼합되어 있는 문서에서 자동으로 문자와 이미지들을 분리해 내는 과정이 필수 적이다. 본 논문에서는 신문이나 광고등에서 볼 수 있는 이미지, 음각 문자와 양각 문자가 섞여 있는 문서에서 문자만을 추출하는 알고리즘을 제안한다. 이 알고리즘은 Run-length code를 이용하여 문자나 이미지의 경계선(bound) 모양의 특징을 추출하여 음각 문자와 이미지, 양각 문자를 구분한다. 그리고 추출된 글자들을 3차원 공간상에 매핑한 후 3차원 면적 가중치 그래프를 이용하여 관련된 단어들로 묶어주는 3차원 그룹핑 알고리즘을 제시한다. 실험결과로는 추출된 문자와 그룹핑된 결과를 보여준다.

• The KIPS Transactions:PartB
• /
• v.19B no.3
• /
• pp.189-194
• /
• 2012

In this paper, we propose a query expansion method based on word graphs using pseudo-relevant and pseudo non-relevant documents to achieve performance improvement in information retrieval. The initially retrieved documents are classified into a core cluster when a document includes core query terms extracted by query term combinations and the degree of query term proximity. Otherwise, documents are classified into a non-core cluster. The documents that belong to a core query cluster can be seen as pseudo-relevant documents, and the documents that belong to a non-core cluster can be seen as pseudo non-relevant documents. Each cluster is represented as a graph which has nodes and edges. Each node represents a term and each edge represents proximity between the term and a query term. The term weight is calculated by subtracting the term weight in the non-core cluster graph from the term weight in the core cluster graph. It means that a term with a high weight in a non-core cluster graph should not be considered as an expanded term. Expansion terms are selected according to the term weights. Experimental results on TREC WT10g test collection show that the proposed method achieves 9.4% improvement over the language model in mean average precision.

• The Journal of the Korea Contents Association
• /
• v.18 no.3
• /
• pp.70-80
• /
• 2018

Due to the recent development of social media and mobile devices, graph data have been using in various fields. In addition, caching techniques for reducing I/O costs in the process of large capacity graph data have been studied. In this paper, we propose a multi-layer caching scheme considering the connectivity of the graph, which is the characteristics of the graph topology, and the history of the past subgraph usage. The proposed scheme divides a cache into Used Data Cache and Prefetched Cache. The Used Data Cache maintains data by weights according to the frequently used sub-graph patterns. The Prefetched Cache maintains the neighbor data of the recently used data that are not used. In order to extract the graph patterns, their past history information is used. Since the frequently used sub-graphs have high probabilities to be reused, they are cached. It uses a strategy to replace new data with less likely data to be used if the memory is full. Through the performance evaluation, we prove that the proposed caching scheme is superior to the existing cache management scheme.

• The Journal of the Korea Contents Association
• /
• v.9 no.2
• /
• pp.142-151
• /
• 2009

Previous document clustering method, NSTC measures similarities between two document pairs using TF-IDF during web document clustering. In this paper, we propose new similarity measure using common phrase-based relational graph, not TF-IDF. This method suggests that weighting common phrases by relational graph presenting relationship among common phrases in document collection. And experimental results indicate that proposed method is more effective in clustering document collection than NSTC.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2013.11a
• /
• pp.1528-1531
• /
• 2013

본 논문은 스테레오 시각에서 3차원 정보를 얻기 위해 bilateral filter를 이용한 그래프 컷 기반의 다해상도 스테레오 영상 정합 방법을 제안하고자 한다. 제안한 방법은 변위도에서 물체의 경계를 명확히 구분하기 위해 bilateral filter를 이용하여 그래프의 각 노드들을 연결하는 경로의 가중치를 결정하고 정합 비용을 통합한다. 정합 과정에서 계산복잡도를 줄이기 위해 계층적 다해상도 구조를 적용하여 영상 피라미드를 만들고, 정합의 정확성을 향상시키기 위해 정합 영역에 변위 평활성과 같은 제약 조건을 적용하여 변위를 전파하는 방법을 사용한다. 실험을 통해 제안한 방법이 변위 탐색 시간을 감소시킬 뿐만 아니라 기존의 그래프 컷의 단점을 보완할 수 있음을 확인하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2022.11a
• /
• pp.354-356
• /
• 2022

소셜 네트워크 및 웹 데이터와 같은 대규모 그래프 데이터를 처리하기 위해 병렬 처리 기반의 기법들이 많이 사용되어 왔다. 본 연구에서는 그래프 형식의 대규모 교통 데이터를 하둡 맵리듀스를 이용하여 처리하는 효과적인 기법을 제안한다. 제안하는 방식에서는 도시의 유동 인구 흐름을 가중치로 고려할 수 있도록 Weighted PageRank 알고리즘을 기반으로 하는 병렬 그래프 알고리즘을 사용하며, 해당 알고리즘을 하둡 맵리듀스에 적용하여 주거 및 근무지 등의 지역을 분류하도록 결과를 분석하였다. 제안 기법을 통한 분석 결과를 기반으로 지역 간 유동 인구 그래프 데이터에서 각 도시의 영향력을 측정하는 페이지랭크, 하둡 맵리듀스 기반의 기법을 제시한다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.26 no.7B
• /
• pp.996-1005
• /
• 2001

본 논문에서는 ASIC 벤더의 셀 라이브러리와 MUX-based FPGA에 있는 고정된 입력을 갖는 연결구조의 수를 최소화하는 하드웨어 할당 알고리듬을 제안한다. 제안된 할당 알고리듬은 연산자간을 연결하는 신호선이 반복적으로 이용되어 연결 신호선 수가 최소가 될 수 있도록 연산자를 할당한다. 연결 구조를 고려한 이분할 그래프에 가중치를 설정하고 변수와 레지스터간의 최대 가중치 매칭을 구함으로써 레지스터 할당을 수행한다. 또한 연결구조에 대한 멀티플렉서의 중복 입력을 제거하고 연산자에 연결된 멀티플렉서간의 입력을 교환하는 입력 정렬 과정으로 연결구조를 최소화한다. 벤치마크 실험을 통하여 제안된 알고리즘의 효용성을 보인다.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.6
• /
• pp.165-173
• /
• 2012

Given a connected, weighted, and undirected graph, the Minimum Spanning Tree (MST) should have minimum sum of weights, connected all vertices, and without any cycle taking place. Borůvka Algorithm is firstly suggested as an algorithm to evaluate the MST, but it is not widely used rather than Prim and Kruskal algorithms. Borůvka algorithm selects the Minimum Weight Edge (MWE) from each vertex with distinct weights in $1^{st}$ stage, and selects the MWE from each MSF (Minimum Spanning Forest) in $2^{nd}$ stage. But the cycle check and the number of MSF in $1^{st}$ stage and $2^{nd}$ stage are difficult to implication by computer program even if it is easy to verify visually. This paper suggests the generalized Borůvka Algorithm, This algorithm selects all of the same MWEs for each vertex, then checks the cycle and constructs MSF for ascending sorted MWEs. Kruskal method bring into this process. if the number of MSF greats then 1, this algorithm selects MWE from ascending sorted inter-MSF edges. The generalized Borůvka algorithm is verified its application by being applied to the 7 graphs with the many minimum weights or distinct weight edges for any vertex. As a result, the generalized Borůvka algorithm is less required for cycle verification then the Kruskal algorithm. Therefore, the generalized Borůvka algorithm is more fast to obtain MST then Kruskal algorithm.

• The Transactions of the Korea Information Processing Society
• /
• v.3 no.4
• /
• pp.766-780
• /
• 1996

This paper presents a mapping scheme for parallel processing using an accurate characterization of the communication overhead. A set of objective functions is formulated to evaluate the optimality of mapping a problem graph into a system graph. One of them is especially suitable for real-time applications of parallel processing. These objective functions are different from the conventional objective functions in that the edges in the problem graph are weighted and the actual distance rather than the nominal distance for the edges in the system graph is employed. This facilitates a more accurate qualification of the communication overhead. An efficient mapping scheme has been developed for the objective functions, where two levels of assignment optimization procedures are employed: initial assignment and pairwise exchange. The mapping scheme has been tested using the hypercube as a system graph.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.26 no.1
• /
• pp.128-133
• /
• 2022

This paper deals with the graph in which the weights of edges are given the distances between two end vertices on a metric space. In particular, we will study about a path P with n vertices for these graphs. We obtain a new graph $\bar{P}$ by augmenting an edge to P. Then the length of the shortest path between two vertices on $\bar{P}$ is considered and we focus on the maximum of these lengths. This maximum is called the diameter of the graph $\bar{P}$. We wish to find the augmented edge to minimize the diameter of $\bar{P}$. Especially, for an arbitrary real number λ > 0, we should determine whether the diameter of $\bar{P}$ is less than or equal to λ and we propose an O(n)-time algorithm for this problem, which improves on the time complexity O(nlogn) previously known. Using this decision algorithm, for the length D of P, we provide an O(nlogD)-time algorithm to find the minimum of the diameter of $\bar{P}$.