• Title/Summary/Keyword: $A^*$ search algorithm

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Adaptive Ontology Matching Methodology for an Application Area (응용환경 적응을 위한 온톨로지 매칭 방법론에 관한 연구)

  • Kim, Woo-Ju;Ahn, Sung-Jun;Kang, Ju-Young;Park, Sang-Un
    • Journal of Intelligence and Information Systems
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    • v.13 no.4
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    • pp.91-104
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    • 2007
  • Ontology matching technique is one of the most important techniques in the Semantic Web as well as in other areas. Ontology matching algorithm takes two ontologies as input, and finds out the matching relations between the two ontologies by using some parameters in the matching process. Ontology matching is very useful in various areas such as the integration of large-scale ontologies, the implementation of intelligent unified search, and the share of domain knowledge for various applications. In general cases, the performance of ontology matching is estimated by measuring the matching results such as precision and recall regardless of the requirements that came from the matching environment. Therefore, most research focuses on controlling parameters for the optimization of precision and recall separately. In this paper, we focused on the harmony of precision and recall rather than independent performance of each. The purpose of this paper is to propose a methodology that determines parameters for the desired ratio of precision and recall that is appropriate for the requirements of the matching environment.

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Extraction of Intestinal Obstruction in X-Ray Images Using PCM (PCM 클러스터링을 이용한 X-Ray 영상에서 장폐색 추출)

  • Kim, Kwang Baek;Woo, Young Woon
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.24 no.12
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    • pp.1618-1624
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    • 2020
  • Intestinal obstruction diagnosis method based on X-ray can affect objective diagnosis because it includes subjective factors of the examiner. Therefore, in this paper, a detection method of Intestinal Obstruction from X-Ray image using Hough transform and PCM is proposed. The proposed method uses Hough transform to detect straight lines from the extracted ROI of the intestinal obstruction X-Ray image and bowel obstruction is extracted by using air fluid level's morphological characteristic detected by the straight lines. Then, ROI is quantized by applying PCM clustering algorithm to the extracted ROI. From the quantized ROI, cluster group that includes bowel obstruction's characteristic is selected and small bowel regions are extracted by using object search from the selected cluster group. The proposed method of using PCM is applied to 30 X-Ray images of intestinal obstruction patients and setting the initial cluster number of PCM to 4 showed excellent performance in detection and the TPR was 81.47%.

Design and Implementation of Reinforcement Learning Agent Using PPO Algorithim for Match 3 Gameplay (매치 3 게임 플레이를 위한 PPO 알고리즘을 이용한 강화학습 에이전트의 설계 및 구현)

  • Park, Dae-Geun;Lee, Wan-Bok
    • Journal of Convergence for Information Technology
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    • v.11 no.3
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    • pp.1-6
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    • 2021
  • Most of the match-3 puzzle games supports automatic play using the MCTS algorithm. However, implementing reinforcement learning agents is not an easy job because it requires both the knowledge of machine learning and the way of complex interactions within the development environment. This study proposes a method in which we can easily design reinforcement learning agents and implement game play agents by applying PPO(Proximal Policy Optimization) algorithms. And we could identify the performance was increased about 44% than the conventional method. The tools we used are the Unity 3D game engine and Unity ML SDK. The experimental result shows that agents became to learn game rules and make better strategic decisions as experiments go on. On average, the puzzle gameplay agents implemented in this study played puzzle games better than normal people. It is expected that the designed agent could be used to speed up the game level design process.

The Improved Estimation of the Least Upper Bound to Search for RSA's Private key

  • Somsuk, Kritsanapong
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.16 no.6
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    • pp.2074-2093
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    • 2022
  • RSA is known as one of the best techniques for securing secret information across an unsecured network. The private key which is one of private parameters is the aim for attackers. However, it is exceedingly impossible to derive this value without disclosing all unknown parameters. In fact, many methods to recover the private key were proposed, the performance of each algorithm is acceptable for the different cases. For example, Wiener's attack is extremely efficient when the private key is very small. On the other hand, Fermat's factoring can quickly break RSA when the difference between two large prime factors of the modulus is relatively small. In general, if all private parameters are not disclosed, attackers will be able to confirm that the private key is unquestionably inside the scope [3, n - 2], where n is the modulus. However, this scope has already been reduced by increasing the greatest lower bound to [dil, n - 2], where dil ≥ 3. The aim of this paper is to decrease the least upper bound to narrow the scope that the private key will remain within this boundary. After finishing the proposed method, the new scope of the private key can be allocated as [dil, dir], where dir ≤ n - 2. In fact, if the private key is extremely close to the new greatest lower bound, it can be retrieved quickly by performing a brute force attack, in which dir is decreased until it is equal to the private key. The experimental results indicate that the proposed method is extremely effective when the difference between prime factors is close to each other and one of two following requirement holds: the first condition is that the multiplier of Euler totient function is very close to the public key's small value whereas the second condition is that the public key should be large whenever the multiplier is far enough.

Audio Fingerprint Extraction Method Using Multi-Level Quantization Scheme (다중 레벨 양자화 기법을 적용한 오디오 핑거프린트 추출 방법)

  • Song Won-Sik;Park Man-Soo;Kim Hoi-Rin
    • The Journal of the Acoustical Society of Korea
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    • v.25 no.4
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    • pp.151-158
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    • 2006
  • In this paper, we proposed a new audio fingerprint extraction method, based on Philips' music retrieval algorithm, which uses the energy difference of neighboring filter-bank and probabilistic characteristics of music. Since Philips method uses too many filter-banks in limited frequency band, it may cause audio fingerprints to be highly sensitive to additive noises and to have too high correlation between neighboring bands. The proposed method improves robustness to noises by reducing the number of filter-banks while it maintains the discriminative power by representing the energy difference of bands with 2 bits where the quantization levels are determined by probabilistic characteristics. The correlation which exists among 4 different levels in 2 bits is not only utilized in similarity measurement. but also in efficient reduction of searching area. Experiments show that the proposed method is not only more robust to various environmental noises (street, department, car, office, and restaurant), but also takes less time for database search than Philips in the case where music is highly degraded.

Task Balancing Scheme of MPI Gridding for Large-scale LiDAR Data Interpolation (대용량 LiDAR 데이터 보간을 위한 MPI 격자처리 과정의 작업량 발란싱 기법)

  • Kim, Seon-Young;Lee, Hee-Zin;Park, Seung-Kyu;Oh, Sang-Yoon
    • Journal of the Korea Society of Computer and Information
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    • v.19 no.9
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    • pp.1-10
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    • 2014
  • In this paper, we propose MPI gridding algorithm of LiDAR data that minimizes the communication between the cores. The LiDAR data collected from aircraft is a 3D spatial information which is used in various applications. Since there are many cases where the LiDAR data has too high resolution than actually required or non-surface information is included in the data, filtering the raw LiDAR data is required. In order to use the filtered data, the interpolation using the data structure to search adjacent locations is conducted to reconstruct the data. Since the processing time of LiDAR data is directly proportional to the size of it, there have been many studies on the high performance parallel processing system using MPI. However, previously proposed methods in parallel approach possess possible performance degradations such as imbalanced data size among cores or communication overhead for resolving boundary condition inconsistency. We conduct empirical experiments to verify the effectiveness of our proposed algorithm. The results show that the total execution time of the proposed method decreased up to 4.2 times than that of the conventional method on heterogeneous clusters.

AGREEMENT BETWEEN DSM-IV AND ICD-10 DIAGNOSIS ON ATTENTION-DEFICIT/HYPERACTIVITY DISORDER (주의력결핍과잉행동장애에 대한 DSM-IV와 ICD-10 진단의 합의)

  • Lee Soyoung Irene;Jung Han-Yone
    • Journal of the Korean Academy of Child and Adolescent Psychiatry
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    • v.16 no.2
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    • pp.192-198
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    • 2005
  • Objectives : This review examines the extent of harmonization between the Diagnostic and Statistical Manual (fourth edition) (DSM-IV) attention deficit hyperactivity disorder (ADHD) and International Classification of Diseases (tenth edition) (ICD-10) hyperkinetic disorder (HKD). Methods : PubMed review of the clinical literatures from 1980 to March 2005 was undertaken using the search term of ADHD, HKD, DSM, ICD, diagnostic criteria, algorithm, and validity. Results : There continues to be a substantial difference in the prevalence of ADHD and HKD. Based on the limited studies that directly compare the most recent two algorithms of ADHD and HKD, several implications for clinical practice and research are discussed. Conclusion : To understand further if the criteria for DSM-IV and ICD-10 for ADHD and HKD are converged or not, more researches on the validity of ADHD and HKD subtypes should be undertaken.

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A User Authentication System Using Face Analysis and Similarity Comparison (얼굴 분석과 유사도 비교를 이용한 사용자 인증 시스템)

  • Ryu Dong-Yeop;Yim Young-Whan;Yoon Sunnhee;Seo Jeong Min;Lee Chang Hoon;Lee Keunsoo;Lee Sang Moon
    • Journal of Korea Multimedia Society
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    • v.8 no.11
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    • pp.1439-1448
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    • 2005
  • In this paper, after similarity of color information in above toro and geometry position analysis of important characteristic information in face and abstraction object that is inputted detects face area using comparison, describe about method to do user certification using ratio information and hair spring degree. Face abstraction algorithm that use color information has comparative advantages than face abstraction algorithm that use form information because have advantage that is not influenced facial degree or site etc. that tip. Because is based on color information, change of lighting or to keep correct performance because is sensitive about color such as background similar to complexion is difficult. Therefore, can be used more efficiently than method to use color information as that detect characteristic information of eye and lips etc. that is facial importance characteristic element except color information and similarity for each object achieves comparison. This paper proposes system that eye and mouth's similarity that calculate characteristic that is ratio red of each individual after divide face by each individual and is segmentalized giving weight in specification calculation recognize user confirming similarity through search. Could experiment method to propose and know that the awareness rate through analysis with the wave rises.

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Shape Optimization of the Plane Truss Structures with the Statical and Natural Frequency Constraints (정적(靜的) 및 고유진동수(固有振動數) 제약조건식(制約條件式)을 고려(考慮)한 평면(平面) 트러스 구조물(構造物)의 형상최적화(形狀最適化)에 관(關)한 연구(硏究))

  • Lee, Gyu Won;Lee, Gun Tea
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.10 no.2
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    • pp.23-38
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    • 1990
  • In this study, decompositive optimization method of two levels was selected to optimize effectively the geometry of the truss which takes the multi-loading condition, and the allowable stress, bucking stress, displacement and natural frequency constraints into consideration. The algorithm of this study is made up of sectional optimization using the feasible direction method in level 1, and geometrical optimization employing Powell's one-direction search method which menimizes only objictive function in level 2. The results of this study acquired by beenning applied to structural model of the truss are as follows : 1. It is verified that the algorithm of this study effectively converges, independent of the initial geometry of the truss and the applied various constraints. 2. The optimum goemetry of the truss varies more considerably according to the constraints selected. 3. Under the condition of the same design, the weight of the truss can be decreased more considerably by means of optimizing even the geometry of truss than by means of optimizing the section of truss while fixing geometrical configuration of it, even though there might be a little difference according to the initial geometry of the truss and the design condition.

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Design of Real-Time Dead Pixel Detection and Compensation System for Image Quality Enhancement in Mobile Camera (모바일 카메라 화질 개선을 위한 실시간 불량 화소 검출 및 보정 시스템의 설계)

  • Song, Jin-Gun;Ha, Joo-Young;Park, Jung-Hwan;Choi, Won-Tae;Kang, Bong-Soon
    • Journal of the Institute of Convergence Signal Processing
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    • v.8 no.4
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    • pp.237-243
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    • 2007
  • In this paper, we propose the Real-time Dead-Pixel Detection and Compensation System for mobile camera and its hardware architecture. The CMOS image sensors as image input devices are becoming popular due to the demand for miniaturized, low-power and cost-effective imaging systems. However a conventional Dead-Pixel Detection Algorithm is disable to detect neighboring dead pixels and it degrades image quality by wrong detection and compensation. To detect dead pixels the proposed system is classifying dead pixels into Hot pixel and Cold pixel. Also, the proposed algorithm is processing line-detector and $5{\times}5$ window-detector consecutively. The line-detector and window-detector can search dead pixels by using one-dimensional(only horizontal) method in low frequency area and two-dimensional(vertical and diagonal) method in high frequency area, respectively. The experimental result shows that it can detect 99% of dead pixels. It was designed in Verilog hardware description language and total gate count is 23K using TSMC 0.25um ASIC library.

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