• Title/Summary/Keyword: inaccuracy

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A Study of Error Analysis for Post Evaluation System on the Construction Projects (건설공사 사후평가시스템 입력오류 분석에 관한 연구)

  • Kim, Kyong-Hoon;Lee, Du-Heon;Kim, Tae-Yeong
    • Korean Journal of Construction Engineering and Management
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    • v.16 no.2
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    • pp.77-85
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    • 2015
  • The data are often missed and many errors of the data are generated in the input process for the post evaluation system on the construction projects, and the reliability of the data falls down much. Accordingly, the detailed analysis about missing and error of data was conducted to ensure reliability of the analysis results about post evaluation on the construction projects. As results in this study, a lot of input data were missed at the initial construction phase, and the data errors were found in the inaccuracy of reference reports, the lack of understanding about input data, and the failure of KRW unit.

Theoretical Benefits and Research Findings Underlying the Use of Microcomputer-Based Laboratory in Science Teaching

  • Han, Hyo-Soon
    • Journal of The Korean Association For Science Education
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    • v.22 no.5
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    • pp.957-969
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    • 2002
  • Theoretical benefits and research findings on the use of Microcomputer-based Laboratory (MBL) are considered for using MBL in a way that will be of benefit to students and teachers, and discussed as a whole for further synthesis, including the formulation of a research agenda for future consensus-based action. Based on the findings obtained from a comprehensive review of the literature, using a systematic approach, the uses of MBL were compared and contrasted for advancing understanding of the teaching and learning processes in science and mathematics. A number of benefits were proposed by MBL developers but not investigated by educational researchers. A few research studies considered the following practical aspects raised by classroom science teachers: technical problems of MBL equipment; inaccuracy or incompleteness of presentation; efficient ways for handling class time with MBL instruction; and development of MBL curriculum materials for their own instruction. This lack of research related to the use of MBL in science classrooms resulted in educational research that was neither respected nor utilized by science teachers. Setting a research agenda based on the theoretical benefits and research findings is necessary for the effective use of MBL in science classrooms can help to maximize the prospects for successful school improvement projects while minimizing the innovation-related frustrations of individuals.

A Numerical Study on the Coupled Dynamics of Ship and Flooding Water (선박 운동과 내부 유동의 연성 운동에 관한 수치해석 연구)

  • Hong, Sa-Young;Kim, Jin;Park, Il-Ryong;Choi, Seok-Kyu
    • Journal of the Society of Naval Architects of Korea
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    • v.43 no.6 s.150
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    • pp.631-637
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    • 2006
  • This paper presents a numerical method to solve the ship motion coupled with internal fluid flow. Physically the internal fluid motion is coupled with the ship motion. Hitherto the previous numerical results of the coupled motion predict only the general tendency with experiments. The main reason of inaccuracy is that the coupled dynamics of ship motion and internal water motion is not accurately accounted. In this study CFD technique based on VOF is employed for the accurate analysis of flooding water motion. Some cases of the 24th ITTC stability committee's benchmark.study for tanker with internal fluid are analyzed by coupling the ship motion and sloshing dynamics. The calculated ship motion is compared with the experimental result to validate the coupled scheme and is in agreement with the experimental result.

Vibration Source Signal Identification of Structures Using ICA (ICA 기법을 이용한 구조물의 진동원 신호 규명)

  • Kim, Kookhyun;Kwon, Hyuk-Min;Cho, Dae-Seung;Kim, Jae-Ho;Jun, Jae-Jin
    • Journal of the Society of Naval Architects of Korea
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    • v.49 no.6
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    • pp.498-503
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    • 2012
  • Independent component analysis (ICA) technique based on statistical independency of the signals is known as suitable to identify the source signals by measuring and separating mixed signals through transfer paths and has successfully applied in the field of medical care, communications and so forth. In this study, the ICA technique is introduced for the identification of excitation sources from measured vibration signals of structures, which can be done by evaluating negentropy of centered and whitened vibration signals and correlation of separated signals. To validate the method, numerical analyses are carried out for a plate and a cylinder structure. The results show that the method can be applied efficiently to source identification of complex structures. Nevertheless, additional studies would be required to complement problems of occasional inaccuracy.

Content-based Image Retrieval Using Color and Shape (색상과 형태를 이용한 내용 기반 영상 검색)

  • Ha, Jeong-Yo;Choi, Mi-Young;Choi, Hyung-Il
    • Journal of the Korea Society of Computer and Information
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    • v.13 no.1
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    • pp.117-124
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    • 2008
  • We suggest CBIR(Content Based Image Retrieval) method using color and shape information. Using just one feature information may cause inaccuracy compared with using more than two feature information. Therefore many image retrieval system use many feature informations like color, shape and other features. We use two feature, HSI color information especially Hue value and CSS(Curvature Scale Space) as shape information. We search candidate image form DB which include feature information of many images. When we use two features, we could approach better result.

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Design & Implementation of an Item Ontology for maintaining the accuracy of data managed by ERP system (ERP 시스템의 데이터 정확성 유지를 위한 물품 온톨로지의 설계 및 구현)

  • Chung Hyun-Sook
    • Journal of Korea Society of Industrial Information Systems
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    • v.10 no.1
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    • pp.38-48
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    • 2005
  • ERP system is a fundamental system that is commonly adopted by most companies that intend to take part in e-business. However, few companies are running ERP systems successfully because of inaccuracy in data managed by ERP system. In this paper, we propose a model and the building process of item ontology which organize concepts describing all items managed by enterprises. In addition, we design and implement a system to create and manage item ontologies. We interface our system with a commercial ERP system, then install and run these systems on a manufacturing company. Our item ontologies and management system might help enterprises when they try to take part in e-business.

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Noise Source Ranking in an Automotive Vehicle Using the Inverse FRF Method (역주파수응답함수를 이용한 자동차 실내 소음 기여도 분석)

  • 전인열;이정권;김병훈;박봉현
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.05a
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    • pp.125-129
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    • 2003
  • The identification of location and strength distribution of extended noise sources is important in the practical noise control engineering, especially in the viewpoint of dealing with the inherent nature of noise problem in question. For noise source ranking inside an automotive vehicle, the window method has been mainly used due to its simplicity. However, time and cost drawbacks in the measurement and inaccuracy due to low-frequency tunneling and lack of phase information have been a serious problem in using this method. In this study, the inverse FRF method was employed to carry out the noise source ranking inside an automotive vehicle and it was also used to predict the interior sound pressure with the change of sound insulation materials. As a result, it was found that the source contribution of vehicle panels could be successfully identified in comparison with the window method. The sound pressure at driver's ear position was predicted based on the obtained data and was compared with the measured data. The agreement in spectral trends was acceptable and their difference in level was within 3㏈ above 500㎐.

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Development of Precise Localization System for Autonomous Mobile Robots using Multiple Ultrasonic Transmitters and Receivers in Indoor Environments (다수의 초음파 송수신기를 이용한 이동 로봇의 정밀 실내 위치인식 시스템의 개발)

  • Kim, Yong-Hwi;Song, Ui-Kyu;Kim, Byung-Kook
    • Journal of Institute of Control, Robotics and Systems
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    • v.17 no.4
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    • pp.353-361
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    • 2011
  • A precise embedded ultrasonic localization system is developed for autonomous mobile robots in indoor environments, which is essential for autonomous navigation of mobile robots with various tasks. Although ultrasonic sensors are more cost-effective than other sensors such as LRF (Laser Range Finder) and vision, they suffer inaccuracy and directional ambiguity. First, we apply the matched filter to measure the distance precisely. For resolving the computational complexity of the matched filter for embedded systems, we propose a new matched filter algorithm with fast computation in three points of view. Second, we propose an accurate ultrasonic localization system which consists of three ultrasonic receivers on the mobile robot and two or more transmitters on the ceiling. Last, we add an extended Kalman filter to estimate position and orientation. Various simulations and experimental results show the effectiveness of the proposed system.

Novel Push-Front Fibonacci Windows Model for Finding Emerging Patterns with Better Completeness and Accuracy

  • Akhriza, Tubagus Mohammad;Ma, Yinghua;Li, Jianhua
    • ETRI Journal
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    • v.40 no.1
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    • pp.111-121
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    • 2018
  • To find the emerging patterns (EPs) in streaming transaction data, the streaming is first divided into some time windows containing a number of transactions. Itemsets are generated from transactions in each window, and then the emergence of itemsets is evaluated between two windows. In the tilted-time windows model (TTWM), it is assumed that people need support data with finer accuracy from the most recent windows, while accepting coarser accuracy from older windows. Therefore, a limited array's elements are used to maintain all support data in a way that condenses old windows by merging them inside one element. The capacity of elements that accommodates the windows inside is modeled using a particular number sequence. However, in a stream, as new data arrives, the current array updating mechanisms lead to many null elements in the array and cause data incompleteness and inaccuracy problems. Two models derived from TTWM, logarithmic TTWM and Fibonacci windows model, also inherit the same problems. This article proposes a novel push-front Fibonacci windows model as a solution, and experiments are conducted to demonstrate its superiority in finding more EPs compared to other models.

A Study on the Ugliness Images Expressed in Modern Make-up -Focused on the Color Expressions- (현대 메이크업에 표현된 추 이미지에 관한 연구 -색채 표현을 중심으로-)

  • 변영희;채금석
    • Journal of the Korean Society of Costume
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    • v.54 no.5
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    • pp.27-39
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    • 2004
  • Since around 1990. some experimental and shocking ugliness images have been expressed in Fashion and Make-up as well as Fine arts. The purpose of this study is to investigate the trends of ugliness images expressed in Modern Make-up from 1995 to 2003, especially focusing on color, and to enlarge the expressions through formative elements and to anticipate the prospect of Make-up in the future. Ugliness is the most negative aesthetic value which is lack of beauty. The 20 century art trends representing the ugly shape have been distorted or deformed or destroyed and extremely exaggerated with yellow, red, black, blue, white, green. The image and color of ugliness can be summarized as historical, avant-garde, decadence, de-constructive, humorous, futuristic trend and Most of colors are the achromatic ones like black, white, dark gray and red. blue, dark brown and so on. These colors cause some negative attributes such as fear. anger, death, devil, Pain, bad, ill omen, sorrow, despair and the like. At the turning Point in 21C are to be extended the range of color according to the experimental attempts such as informal, collage, graphic and the forth. Lastly, The characteristics of ugliness images expressed in the color of Modern Make-up have been analyzed into formlessness and inaccuracy and deformation by Karl Rosenkranz's theory.