• Proceedings of the Korea Information Processing Society Conference
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• 2004.11a
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• pp.51-54
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• 2004

시멘틱 웹은 기존의 웹과는 달리 정보의 의미가 정의되고, 이들 간의 의미적 연결을 지원한다는 특징이 있어서, 최근 차세대 웹으로 부각되고 있다. 이러한 의미적 연결을 위해서 시맨틱 웹의 기반인 온톨로지가 필요하다. 온톨로지는 리소스에 대한 메타데이터를 정의하여 의미적 연결이 가능하게 하므로 효율적인 정보 검색이 가능하다. 이 논문에서는 정보 검색의 효율을 증가시키기 위해서 시맨틱 웹의 핵심인 온톨로지 기반의 정보 검색 시스템을 제안한다. 쇼핑 사이트에서 효율적인 마케팅을 위해 사용자의 구매 패턴을 조사하여 고객에게 알맞은 정보 추천을 하기 위한 것을 목적으로 한다. 온톨로지의 구축은 XTM을 기반으로 토픽맵을 이용하였다. 그리고 온톨로지를 기반으로, 사용자의 구매패턴을 찾아서 정확한 정보 전달을 위해서 데이터 마이닝 기법을 이용하였다. 빈발패턴 트리 기법을 기반으로 하는 멀티 레벨 멀티 디멘션 빈발 패턴 마이닝 알고리즘을 이용하여 사용자 패턴을 분석하여 정보 검색에 효율을 기하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.593-596
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• 2021

본 논문에서는 지형의 고도와 기울기를 고려하여 사운드의 확산과 회절을 인터렉티브하게 표현할 수 있는 사운드 합성 기법을 제안한다. 우리의 접근 방식은 광선 추적법(Raytracing)을 기반으로 소리의 크기를 보여줄 수 있는 사운드 강도 맵을 빠르게 계산한다. 지형의 고도와 기울기 값을 고려하여 소리의 강도 맵에 가중치를 적용하여, 결과적으로 지형의 지오메트리 분석인 큰 계산 과정을 피하고 지형을 고려한 소리의 크기를 인터렉티브하게 업데이트한다. 이 과정에서 소리의 근원지에 따른 고도 간의 격차를 계산하여 소리의 크기를 자동으로 감쇠시키며, 주변 지형의 공간 기울기를 기반으로 기울기의 차에 따라 소리의 크기를 자동으로 감쇠시킨다. 본 논문에서 제안하는 방법을 이용한 소리는 실제 높낮이가 있는 현실의 지형에서 듣는 소리의 전파 및 감쇠와 유사한 형태를 보여주며, 소리의 위치에 따라서 소리 감소 패턴이 변경되고, 또한, 지형에 따라서 소리의 크기가 제어되는 결과를 보여준다.

• Annual Conference on Human and Language Technology
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• 2020.10a
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• pp.563-568
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• 2020

본 연구에서는 블랙박스로 알려진 딥러닝 모델에 설명 근거를 제공할 수 있는 설명자 모델을 적용해 보았다. 영화평 감성 분석을 위해 MLP, CNN으로 구성된 딥러닝 모델과 결정트리의 앙상블인 Gradient Boosting 모델을 이용하여 감성 분류기를 구축하였다. 설명자 모델로는 기울기(gradient)을 기반으로 하는 IG와 레이어 사이의 가중치(weight)을 기반으로 하는 CAM, 그리고 설명가능한 대리 모델을 이용하는 LIME과 입력 속성에 대한 선형모델을 추정하는 SHAP을 사용하였다. 설명자 모델의 특성을 보기 위하여 히트맵과 관련성 높은 N개의 속성을 추출해 보았다. 설명자가 제공하는 기여도에 따라 입력 속성을 제거해 가며 분류기 성능 변화를 측정하는 정량적 평가도 수행하였다. 또한, 사람의 판단 근거와의 일치도를 살펴볼 수 있는 '설명 근거 정확도'라는 새로운 평가 방법을 제안하여 적용해 보았다.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.1
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• pp.9-20
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• 2005

Recently, the MPEG-7 standard a multimedia content description standard is wide]y used for content based image/video retrieval systems. However, since the descriptors standardized in MPEG-7 are usually multidimensional and the problem called 'Curse of dimensionality', previously proposed indexing methods(for example, multidimensional indexing methods, dimensionality reduction methods, filtering methods, and so on) could not be used to effectively index the multimedia database represented in MPEG-7. This paper proposes an efficient multimedia data indexing mechanism reflecting the characteristics of MPEG-7 visual descriptors. In the proposed indexing mechanism, the descriptor is transformed into a histogram of some attributes. By representing the value of each bin as a binary number, the histogram itself that is a visual descriptor for the object in multimedia database could be represented as a bit string. Bit strings for all objects in multimedia database are collected to form an index file, bitmap index, in the proposed indexing mechanism. By XORing them with the descriptors for query object, the candidate solutions for similarity search could be computed easily and they are checked again with query object to precisely compute the similarity with exact metric such as Ll-norm. These indexing and searching mechanisms are efficient because the filtering process is performed by simple bit-operation and it reduces the search space dramatically. Upon experimental results with more than 100,000 real images, the proposed indexing and searching mechanisms are about IS times faster than the sequential searching with more than 90% accuracy.

• Journal of KIISE:Databases
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• v.30 no.3
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• pp.225-236
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• 2003

MOLAP systems store data in a multidimensional away called a 'cube' and access them using way indexes. When a cube is placed into disk, it can be Partitioned into a set of chunks of the same side length. Such a cube storage scheme is called the chunk-based MOLAP cube storage scheme. It gives data clustering effect so that all the dimensions are guaranteed to get a fair chance in terms of the query processing speed. In order to achieve high space utilization, sparse chunks are further compressed. Due to data compression, the relative position of chunks cannot be obtained in constant time without using indexes. In this paper, we propose a bitmap index for chunk-based MOLAP cubes. The index can be constructed along with the corresponding cube generation. The relative position of chunks is retained in the index so that chunk retrieval can be done in constant time. We placed in an index block as many chunks as possible so that the number of index searches is minimized for OLAP operations such as range queries. We showed the proposed index is efficient by comparing it with multidimensional indexes such as UB-tree and grid file in terms of time and space.

• Journal of Internet Computing and Services
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• v.15 no.6
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• pp.99-106
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• 2014

Generation and analysis methods have been proposed in recent years, such as using a natural language and formal language processing, artificial intelligence algorithms based knowledge model is effective meaning. its semantic based knowledge model has been used effective decision making tree and problem solving about specific context. and it was based on static generation and regression analysis, trend analysis with behavioral model, simulation support for macroeconomic forecasting mode on especially in a variety of complex systems and social network analysis. In this study, in this sense, integrating knowledge-based models, This paper propose a text mining derived from the inter-Topic model Integrated formal methods and Algorithms. First, a method for converting automatically knowledge map is derived from text mining keyword map and integrate it into the semantic knowledge model for this purpose. This paper propose an algorithm to derive a method of projecting a significant topic map from the map and the keyword semantically equivalent model. Integrated semantic-based knowledge model is available.

• Journal of the Korea Society of Computer and Information
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• v.15 no.10
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• pp.11-17
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• 2010

Mobile device, one of typical devices in ubiquitous environment, is received attention owing to portability. In these days, technical researches on a kind of the device are focusing on applications of smart phone. For example, the techniques using geographical position and applied instances such as augmented reality techniques are gradually increasing. That makes data processing important. Mobile application services for users also require various application techniques based on moving objects. In addition, they require the techniques that processed data are needed to be shown in visualization. However, this is reality that it lacks of showing visualization works to improve the understanding of thing what it is. To reduce or solve the problems, in this paper we show the results to implement the R tree based 3 dimension index architecture in visualization. Further, we implemented and present creating objects, showing in 3D for the objects, catching spatial position on a node map through mini map function and improving the understanding of R tree by visualizing.

• Journal of KIISE:Databases
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• v.27 no.1
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• pp.13-21
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• 2000

Online analytical processing (OLAP) systems are introduced to support decision support systems. Many researches focussed on efficient processing of aggregate functions that usually occur in OLAP queries. However, most previous researches in the literature are deal with the situation in which aggregate functions arc applied to all the values in a given range. Since those approaches utilize characteristic of aggregate functions applied to a range, they are difficult to be applied to a muitipoint query that is a query considering only some points in a given range. In this paper, we propose the Ranking Index and the flanking Decision Tree (RDT) for efficient evaluation of multipoints MAX/MIN queries. The ranking of possible MAX/MIN values are computed with RDT Then MAX/MIN values can be acquired from the Ranking Index. We show through experiments that our method provides high performance in most situations. In other words, the proposed method is robust as well as efficient. A single common set of precomputed results for both MAX and MIN values is another advantage of the proposed method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.8
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• pp.1213-1225
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• 1993

Hypermedia systems have the browsing mechanism using links and provide navigation tools to retrieve and represent multimedia information. In this study we designed and implemented a hypermedia system which has the hierarchical group and local map for effective navigation. We also propose the clustering mechanism which constructs a cluster tree and uses this knowledge for navigation. The system has been designed to integrate the browsing and searching function of the hypermedia system for efficient multimedia information retrieval and user-interface. This system can be used to develop hypermedia application systems in the area of encyclopedia, reference document information, electronic dictionary and electronic book.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.4 s.304
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• pp.95-102
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• 2005

In this paper, we propose a user friendly object-based image retrieval system using the interaction between cortex and hippocampus. Most existing ways of queries in content-based image retrieval rely on query by example or query by sketch. But these methods of queries are not adequate to needs of people's various queries because they are not easy for people to use and restrict. We propose a method of automatic color object extraction using CSB tree map(Color and Spatial based Binary をn map). Extracted objects were transformed to bit stream representing information such as color, size and location by region labelling algorithm and they are learned by the hippocampal neural network using the interplay between cortex and hippocampus. The cells of exciting at peculiar features in brain generate the special sign when people recognize some patterns. The existing neural networks treat each attribute of features evenly. Proposed hippocampal neural network makes an adaptive fast content-based image retrieval system using excitatory learning method that forwards important features to long-term memories and inhibitory teaming method that forwards unimportant features to short-term memories controlled by impression.