• Title/Summary/Keyword: Dynamic Graph Search

Search Result 29, Processing Time 0.021 seconds

An Efficient Topology/Parameter Control in Evolutionary Design for Multi-domain Engineering Systems

  • Seo, Ki-Sung
    • International Journal of Fuzzy Logic and Intelligent Systems
    • /
    • v.5 no.2
    • /
    • pp.108-113
    • /
    • 2005
  • This paper suggests a control method for an efficient topology/parameter evolution in a bond graph-based GP design framework that automatically synthesizes designs for multi-domain, lumped parameter dynamic systems. We adopt a hierarchical breeding control mechanism with fitness-level-dependent differences to obtain better balancing of topology/parameter search - biased toward topological changes at low fitness levels, and toward parameter changes at high fitness levels. As a testbed for this approach in bond graph synthesis, an eigenvalue assignment problem, which is to find bond graph models exhibiting minimal distance errors from target sets of eigenvalues, was tested and showed improved performance for various sets of eigenvalues.

Hierarchical Structure in Semantic Networks of Japanese Word Associations

  • Miyake, Maki;Joyce, Terry;Jung, Jae-Young;Akama, Hiroyuki
    • Proceedings of the Korean Society for Language and Information Conference
    • /
    • 2007.11a
    • /
    • pp.321-329
    • /
    • 2007
  • This paper reports on the application of network analysis approaches to investigate the characteristics of graph representations of Japanese word associations. Two semantic networks are constructed from two separate Japanese word association databases. The basic statistical features of the networks indicate that they have scale-free and small-world properties and that they exhibit hierarchical organization. A graph clustering method is also applied to the networks with the objective of generating hierarchical structures within the semantic networks. The method is shown to be an efficient tool for analyzing large-scale structures within corpora. As a utilization of the network clustering results, we briefly introduce two web-based applications: the first is a search system that highlights various possible relations between words according to association type, while the second is to present the hierarchical architecture of a semantic network. The systems realize dynamic representations of network structures based on the relationships between words and concepts.

  • PDF

DL-RRT* algorithm for least dose path Re-planning in dynamic radioactive environments

  • Chao, Nan;Liu, Yong-kuo;Xia, Hong;Peng, Min-jun;Ayodeji, Abiodun
    • Nuclear Engineering and Technology
    • /
    • v.51 no.3
    • /
    • pp.825-836
    • /
    • 2019
  • One of the most challenging safety precautions for workers in dynamic, radioactive environments is avoiding radiation sources and sustaining low exposure. This paper presents a sampling-based algorithm, DL-RRT*, for minimum dose walk-path re-planning in radioactive environments, expedient for occupational workers in nuclear facilities to avoid unnecessary radiation exposure. The method combines the principle of random tree star ($RRT^*$) and $D^*$ Lite, and uses the expansion strength of grid search strategy from $D^*$ Lite to quickly find a high-quality initial path to accelerate convergence rate in $RRT^*$. The algorithm inherits probabilistic completeness and asymptotic optimality from $RRT^*$ to refine the existing paths continually by sampling the search-graph obtained from the grid search process. It can not only be applied to continuous cost spaces, but also make full use of the last planning information to avoid global re-planning, so as to improve the efficiency of path planning in frequently changing environments. The effectiveness and superiority of the proposed method was verified by simulating radiation field under varying obstacles and radioactive environments, and the results were compared with $RRT^*$ algorithm output.

Plagiarism Detection Using Dependency Graph Analysis Specialized for JavaScript (자바스크립트에 특화된 프로그램 종속성 그래프를 이용한 표절 탐지)

  • Kim, Shin-Hyong;Han, Tai-Sook
    • Journal of KIISE:Software and Applications
    • /
    • v.37 no.5
    • /
    • pp.394-402
    • /
    • 2010
  • JavaScript is one of the most popular languages to develope web sites and web applications. Since applicationss written in JavaScript are sent to clients as the original source code, they are easily exposed to plagiarists. Therefore, a method to detect plagiarized JavaScript programs is necessary. The conventional program dependency graph(PDG) based approaches are not suitable to analyze JavaScript programs because they do not reflect dynamic features of JavaScript. They also generate false positives in some cases and show inefficiency with large scale search space. We devise a JavaScript specific PDG(JS PDG) that captures dynamic features of JavaScript and propose a JavaScript plagiarism detection method for precise and fast detection. We evaluate the proposed plagiarism detection method with experiment. Our experiments show that our approach can detect false-positives generated by conventional PDG and can prune the plagiarism search space.

Implementation and Evaluation of Path-Finding Algorithm using Abstract Graphs (추상 그래프를 활용한 경로 탐색 알고리즘의 구현 및 성능 평가)

  • Kim, Ji-Soo;Lee, Ji-wan;Cho, Dae-Soo
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
    • /
    • 2009.10a
    • /
    • pp.245-248
    • /
    • 2009
  • Recently, Many studies have been progressing to path-finding with dynamic information on the Terminal Based Navigation System(TBNS). However, the most of existing algorithms are based on $A{\ast}$ algorithm. Path-finding algorithms which use heuristic function may occur a problem of the increase of exploring cost in case of that there is no way determined by heuristic function or there are 2 way more which have almost same cost. In this paper, two abstract graph(AG) that are different method of construction, Homogeneous Node merging($AG^H$) and Connected Node Merging($AG^C$), are implemented. The abstract graph is a simple graph of real road network. The method of using the abstract graph is proposed for reducing dependency of heuristic and exploring cost. In result of evaluation of performance, $AG^C$ has better performance than $AG^H$ at construction cost but $AG^C$ has worse performance than $AG^H$ exploring cost.

  • PDF

Implementation and Evaluation of Path-Finding Algorithm using Abstract Graphs (추상 그래프를 활용한 경로 탐색 알고리즘의 구현 및 성능 평가)

  • Kim, Ji-Soo;Lee, Ji-Wan;Cho, Dae-Soo
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.13 no.11
    • /
    • pp.2367-2372
    • /
    • 2009
  • Recently, Many studies have been progressing to path-finding adapted dynamic information on the Terminal Based Navigation System(TBNS). The algorithms proposed are based on $A^*$ algorithm. Path-finding algorithms which use heuristic function may occur a problem of the increase of exploring cost. Path-finding with an abstract graph which expresses real road network as a simple graph is proposed for reducing dependency of heuristic and exploring cost. In this paper, two abstract graph that are different method of construction, Homogeneous Node merging($AG^H$) and Connected Node Merging($AG^C$), are implemented. In result of evaluation of performance, $AG^C$ has better performance than $AG^H$ at construction cost and the number of node access but $AG^C$ has worse performance than AGH at exploring cost.

Dynamic Adaptive Model for WebMedia Educational Systems based on Discrete Probability Techniques (이산 확률 기법에 기반한 웹미디어 교육 시스템을 위한 동적 적응 모델)

  • Lee, Yoon-Soo
    • Journal of the Korea Computer Industry Society
    • /
    • v.5 no.9
    • /
    • pp.921-928
    • /
    • 2004
  • This paper proposed dynamic adaptive model based on discrete probability distribution function and user profile in web based HyperMedia educational systems. This modelsrepresents application domain to weighted direction graph of dynamic adaptive objects andmodeling user actions using dynamically approach method structured on discrete probability function. Proposed probabilitic analysis can use that presenting potential attribute to useractions that are tracing search actions of user in WebMedia structure. This approach methodscan allocate dynamically appropriate profiles to user.

  • PDF

Hierarchical Stereo Matching with Color Information (영상의 컬러 정보를 이용한 계층적 스테레오 정합)

  • Kim, Tae-June;Yoo, Ji-Sang
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.34 no.3C
    • /
    • pp.279-287
    • /
    • 2009
  • In this paper, a hierarchical stereo matching with color information is proposed. To generate an initial disparity map, feature based stereo matching is carried out and to generate a final disparity map, hierarchical stereo matching is carried out. The boundary (edge) region is obtained by segmenting a given image into R, G, B and White components. From the obtained boundary, disparity is extracted. The initial disparity map is generated when the extracted disparity is spread to the surrounding regions by evaluating autocorrelation from each color region. The initial disparity map is used as an initial value for generating the final disparity map. The final disparity map is generated from each color region by changing the size of a block and the search range. 4 test images that are provided by Middlebury stereo vision are used to evaluate the performance of the proposed algorithm objectively. The experiment results show better performance compared to the Graph-cuts and Dynamic Programming methods. In the final disparity map, about 11% of the disparities for the entire image were inaccurate. It was verified that the boundary for the non-contiguous point was clear in the disparity map.

Large Vocabulary Continuous Speech Recognition Based on Language Model Network (언어 모델 네트워크에 기반한 대어휘 연속 음성 인식)

  • 안동훈;정민화
    • The Journal of the Acoustical Society of Korea
    • /
    • v.21 no.6
    • /
    • pp.543-551
    • /
    • 2002
  • In this paper, we present an efficient decoding method that performs in real time for 20k word continuous speech recognition task. Basic search method is a one-pass Viterbi decoder on the search space constructed from the novel language model network. With the consistent search space representation derived from various language models by the LM network, we incorporate basic pruning strategies, from which tokens alive constitute a dynamic search space. To facilitate post-processing, it produces a word graph and a N-best list subsequently. The decoder is tested on the database of 20k words and evaluated with respect to accuracy and RTF.

Ontology based Educational Systems using Discrete Probability Techniques (이산 확률 기법을 이용한 온톨로지 기반 교육 시스템)

  • Lee, Yoon-Soo
    • Journal of the Korea Society of Computer and Information
    • /
    • v.12 no.1 s.45
    • /
    • pp.17-24
    • /
    • 2007
  • Critical practicality problems are cause to search the presentation and contents according to user request and purpose in previous internet system. Recently, there are a lot of researches about dynamic adaptable ontology based system. We designed ontology based educational system which uses discrete probability and user profile. This system provided advanced usability of contents by ontology and dynamic adaptive model based on discrete probability distribution function and user profile in ontology educational systems. This models represents application domain to weighted direction graph of dynamic adaptive objects and modeling user actions using dynamically approach method structured on discrete probability function. Proposed probability analysis can use that presenting potential attribute to user actions that are tracing search actions of user in ontology structure. This approach methods can allocate dynamically appropriate profiles to user.

  • PDF