• Communications for Statistical Applications and Methods
• /
• v.11 no.3
• /
• pp.609-617
• /
• 2004

To present graph of probability densities, many softwares and graphical tools use methods that link points or straight lines. However, the methods can't display exactly and smoothly the graph and are not efficient from the viewpoint of process time. One method to overcome these shortcomings is utilizing interpolation methods. In these methods, selecting the number and location of knots is an important factor. This article proposes an algorithm to select knots for graphically presenting densities and implements graph components based on the algorithm.

• International Journal of Contents
• /
• v.17 no.3
• /
• pp.1-14
• /
• 2021

Since the outbreak of the coronavirus disease 2019 (COVID-19) pandemic, a lot of efforts have been made in the field of data science to help combat against this disease. Among them, forecasting the number of cases of infection is a crucial problem to predict the development of the pandemic. Many deep learning-based models can be applied to solve this type of time series problem. In this research, we would like to take a step forward to incorporate spatial data (geography) with time series data to forecast the cases of region-level infection simultaneously. Specifically, we model a single spatio-temporal graph, in which nodes represent the geographic regions, spatial edges represent the distance between each pair of regions, and temporal edges indicate the node features through time. We evaluate this approach in COVID-19 in a Korean dataset, and we show a decrease of approximately 10% in both RMSE and MAE, and a significant boost to the training speed compared to the baseline models. Moreover, the training efficiency allows this approach to be extended for a large-scale spatio-temporal dataset.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2021.06a
• /
• pp.204-207
• /
• 2021

LiDAR 장비 및 SfM 과 MVS 방법을 이용하여 생성된 point cloud 와 mesh 에는 항상 노이즈가 포함되어 있다. 이러한 노이즈를 제거하기 위해선 노이즈와 edge 를 효과적으로 구분해낼 수 있어야 한다. 노이즈를 제거하기 위해 mesh 로부터 edge 를 먼저 구분해낸 후 edge 에 해당하는 영역과 평면에 해당하는 영역에 서로 다른 필터를 사용하는 많은 연구들이 있지만 강한 노이즈가 포함된 mesh 에서는 edge를 잘 구분해내지 못하는 문제가 존재한다. 이러한 방법들은 mesh 로부터 edge 를 구분해내는 알고리즘의 성능이 노이즈를 제거하는 전체 알고리즘의 성능에 큰 영향을 주기 때문에 강한 노이즈에서도 edge 를 잘 구분해낼 수 있는 알고리즘이 필요하다. 본 논문에서는 PCA 와 graph-cut 을 이용하여 강한 노이즈가 포함된 mesh 에서 edge 영역을 추출하는 알고리즘을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2023.05a
• /
• pp.386-388
• /
• 2023

본 논문은 고성능 스토리지를 사용하는 환경에서 대규모 그래프를 분석을 위한 GPU 기반 그래프 분석 엔진의 I/O 최적화 전략을 제안한다. 사전 실험을 통해 최신 GPU 기반 그래프 엔진인 RealGraph^GPU 가 고성능 스토리지의 대역폭을 충분히 활용하지 못하고 있음을 발견하였다. 이를 개선하기 위해 (1) User-space I/O, (2) Asynchronous I/O 두 가지 최적화 전략을 적용하였으며, 실험을 통해 두 전략이 RealGraphGPU 의 그래프 분석 성능 향상시키는 데 효과적임을 확인하였다.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.33 no.3
• /
• pp.17-28
• /
• 2008

The Steiner arborescence problem is known to be NP-hard. The objective of this problem is to find a minimal Steiner tree which starts from a designated node and spans all given terminal nodes. This paper proposes a method based on a two-step procedure to solve this problem efficiently. In the first step, graph reduction rules eliminate useless nodes and arcs which do not contribute to make an optimal solution. In the second step. ant colony algorithm with use of Prim's algorithm is used to solve the Steiner arborescence problem in the reduced graph. The proposed method based on a two-step procedure is tested in the five test problems. The results show that this method finds the optimal solutions to the tested problems within 50 seconds. The algorithm can be applied to undirected Steiner tree problems with minor changes. 18 problems taken from Beasley are used to compare the performances of the proposed algorithm and Singh et al.'s algorithm. The results show that the proposed algorithm generates better solutions than the algorithm compared.

• ETRI Journal
• /
• v.9 no.1
• /
• pp.84-96
• /
• 1987

The equality relation is very important in mechanical theorem proving procedures. A proposed inference rule called RHU-resolution is intended to extend the hyperparamodulation[23, 9] by introducing a bidirectional proof search that simultaneously employs a forward reasoning and a backward reasoning, and generalize it by incorporating beneflts of extended hyper steps with a preprocessing process, that includes a subsumption check in an equality graph and a high level planning. The forward reasoning in RHU-resolution may replace the role of the function substitution link.[9] That is, RHU-deduction without the function substitution link gets a proof. In order to control explosive generation of positive equalities by the forward reasoning, we haue put some restrictions on input clauses and k-pd links, and also have included a control strategy for a positive-positive linkage, like the set-of-support concept, A linking path between two end terms can be found by simple checking of linked unifiability using the concept of a linked unification. We tried to prevent redundant resolvents from generating by preprocessing using a subsumption check in the subsumption based eauality graph(SPD-Graph)so that the search space for possible RHU-resolution may be reduced.

• ETRI Journal
• /
• v.39 no.4
• /
• pp.592-604
• /
• 2017

Intrusion detection is very important for network situation awareness. While a few methods have been proposed to detect network intrusion, they cannot directly and effectively utilize semi-quantitative information consisting of expert knowledge and quantitative data. Hence, this paper proposes a new detection model based on a directed acyclic graph (DAG) and a belief rule base (BRB). In the proposed model, called DAG-BRB, the DAG is employed to construct a multi-layered BRB model that can avoid explosion of combinations of rule number because of a large number of types of intrusion. To obtain the optimal parameters of the DAG-BRB model, an improved constraint covariance matrix adaption evolution strategy (CMA-ES) is developed that can effectively solve the constraint problem in the BRB. A case study was used to test the efficiency of the proposed DAG-BRB. The results showed that compared with other detection models, the DAG-BRB model has a higher detection rate and can be used in real networks.

• Journal of Information Technology Services
• /
• v.12 no.1
• /
• pp.247-257
• /
• 2013

A narrative structure is essential for a story generator to create a story plot. In digital storytelling system, a narrative structure can be generally designed as a tree or a graph, and the story generator in the digital storytelling system creates continuous story plots based on the narrative structure. When a narrative structure is designed with a tree or a graph, it is hard for the story generator to create various kinds of story-plots due to the inflexible nature of a tree or graph structure. It may result in degrading the quality of story-plots to provide similar story-plot to various kind of user. In this paper, we proposed an approach to create a story-plot based on association analysis of data mining to overcome the disadvantage. In detail, we defined a narrative structure which consists of narrative patterns, and then implemented a story generator which creates a story-plot using the proposed narrative structure. As a result, we confirmed that implemented story generator was able to create a story-plot according to understanding level of user in case study.

• The KIPS Transactions:PartB
• /
• v.19B no.1
• /
• pp.37-42
• /
• 2012

The pseudo relevance feedback suggests that frequent words at the top documents are related to initial query. However, the main drawback associated with the term frequency method is the fact that it relies on feature independence, and disregards any dependencies that may exist between words in the text. In this paper, we propose query expansion based on word graph using term proximity. It supplements term frequency method. On TREC WT10g test collection, experimental results in MAP(Mean Average Precision) show that the proposed method achieved 6.4% improvement over language model.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.16 no.1
• /
• pp.94-100
• /
• 2006

Computing paradigm shift to internet-based one has accelerated the use of XML in diverse applications. This phenomena has made the explosive increases of XML data and it triggered many active researches in maintaining very huge amount of XML data in turn. In this paper we present a persistent graph-based XML indexing lot data-centric XML data. In our approach we use 3 graphs to represent XML indexes and XML data itself. They are schema graph, data graph index. And then we have mapped those graphs to B+-trees the persistency. With our approach we can achieve linear query execution time with the increase of XML sizes.