• Title, Summary, Keyword: Preprocessing

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Influence of Data Preprocessing

  • Zhu, Changming;Gao, Daqi
    • Journal of Computing Science and Engineering
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    • v.10 no.2
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    • pp.51-57
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    • 2016
  • In this paper, we research the influence of data preprocessing. We conclude that using different preprocessing methods leads to different classification performances. Moreover, not all data preprocessing methods are necessary, and a criterion is given to make sure which data preprocessing is necessary and which one is effective. Experiments on some real-world data sets validate that different data preprocessing methods result in different effects. Furthermore, experiments about some algorithms with different preprocessing methods also confirm that preprocessing has a great influence on the performance of a classifier.

Performance Analysis of Preprocessing Algorithm in Container Terminal and Suggestion for Optimum Selection (컨테이너 터미널의 선처리 알고리즘 성능분석과 최적선택 제안)

  • Park, Young-Kyu
    • The Journal of Distribution Science
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    • v.16 no.12
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    • pp.95-104
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    • 2018
  • Purpose - In order to gain the upper hand in competition between container terminals, efforts to improve container terminal productivity continue. Export containers arrive randomly in the container terminal and are carried in the container terminal yard according to the arrival order. On the other hand, containers are carried out of the container terminal yard in order based on container weight, not in order of arrival. Because the carry-in order and the carry-out order are different, rehandling may occur, which reduces the performance of the container terminals. In order to reduce rehandling number, containers can be moved in advance when they arrive, which is called preprocessing. This paper proposes an effective preprocessing algorithm and analyzes the factors that affect the productivity of the container terminals. It also provides a way to choose the best factors for preprocessing for a variety of situations. Research design, data, and methodology - To analyze the impact of factors affecting the performance of preprocessing algorithms presented in this paper, simulations are performed. The simulations are performed for two types of bays, 12 stacks with 8 tiers, and 8 stacks with 6 tiers. Results - The results of the factor analysis that affects the performance of the preprocessing algorithm were as follows. (1) As the LMF increased, preprocessing number increases and rehandling number decreased. (2) The LML effect was greatest when the LML changed from 0 to 1, and that the effect decreased when it changed above 1. (3) The sum of preprocessing number and rehandling number was then shown to be increased after decrease, as the LMF increased. (4) In the case of NCI, a decrease in NCI showed that the containers would become more grouped and thus the performance was improved. (5) There was a positive effect in the case of EFS. Conclusion - In this paper, preprocessing algorithm was proposed and it was possible to choose the best factors for preprocessing for a variety of situations through simulations. Further research related to this study needs to be carried out in the following topic : a study on the improvement of container performance by connecting the preprocessing with remarshalling.

Design of a real-time image preprocessing system with linescan camera interface (라인스캔 카메라 인터페이스를 갖는 실시간 영상 전처리 시스템의 설계)

  • Lyou, Kyeong;Kim, Kyeong-Min;Park, Gwi-Tae
    • Journal of Institute of Control, Robotics and Systems
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    • v.3 no.6
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    • pp.626-631
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    • 1997
  • This paper represents the design of a real-time image preprocessing system. The preprocessing system performs hardware-wise mask operations and thresholding operations at the speed of camera output single rate. The preprocessing system consists of the preprocessing board and the main processing board. The preprocessing board includes preprocessing unit that includes a $5\times5$ mask processor and LUT, and can perform mask and threshold operations in real-time. To achieve high-resolution image input data($20485\timesn$), the preprocessing board has a linescan camera interface. The main processing board includes the image processor unit and main processor unit. The image processor unit is equipped with TI's TMS320C32 DSP and can perform image processing algorithms at high speed. The main processor unit controls the operation of total system. The proposed system is faster than the conventional CPU based system.

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Preprocessing in large scale linear programming problems (대형선형계획문제의 사전처리)

  • 성명기;박순달
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • pp.285-288
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    • 1996
  • Generally MPS, standardized by IBM, is the input type of large scale linear programming problems, and there may be unnecessary variables or constraints. These can be discarded by preprocessing. As the size of a problem is reduced by preprocessing, the running time is reduced. And more, the infeasibility of a problem may be detected before using solution methods. When the preprocessing implemented by this paper is used in NETLIB problems, it removes unnecessary variables and constraints by 21%, 15%, respectively. The use of preprocessing gives in the average 21% reduction in running time by applying the interior point method. Preprocessing can detect 10 out of 30 infeasible NETLIB problems.

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An Implementation of Preprocessing for Interior Point Methods for Linear Programming (내부점 방법을 위한 사전처리의 구현)

  • 성명기;임성묵;박순달
    • Journal of the Korean Operations Research and Management Science Society
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    • v.24 no.1
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    • pp.1-11
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    • 1999
  • We classified preprocessing methods into (1) analytic methods, (2) methods for removing implied free variables, (3) methods using pivot or elementary row operations, (4) methods for removing linearly dependent rows and columns and (5) methods for dense columns. We noted some considerations to which should be paid attention when preprocessing methods are applied to interior point methods for linear programming. We proposed an efficient order of preprocessing methods and data structures. We also noted the recovery process for dual solutions. We implemented the proposed preprocessing methods. and tested it with 28 large scale problems of NETLIB. We compared the results of it with those of preprocessing routines of HOPDM, BPDPM and CPLEX.

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A Nonparametric Approach for Noisy Point Data Preprocessing

  • Xi, Yongjian;Duan, Ye;Zhao, Hongkai
    • International Journal of CAD/CAM
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    • v.9 no.1
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    • pp.31-36
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    • 2010
  • 3D point data acquired from laser scan or stereo vision can be quite noisy. A preprocessing step is often needed before a surface reconstruction algorithm can be applied. In this paper, we propose a nonparametric approach for noisy point data preprocessing. In particular, we proposed an anisotropic kernel based nonparametric density estimation method for outlier removal, and a hill-climbing line search approach for projecting data points onto the real surface boundary. Our approach is simple, robust and efficient. We demonstrate our method on both real and synthetic point datasets.

An Implementation of Preprocessing for the Simplex Method (단체법을 위한 사전처리의 구현)

  • Lim, Sung-Mook;Seong, Myeong-Ki;Park, Soon-Dal
    • Journal of Korean Institute of Industrial Engineers
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    • v.25 no.2
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    • pp.217-225
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    • 1999
  • Preprocessing is the essential technique in the implementation of the simplex method for large scale linear programming problems. In this research, we explained the effect of preprocessing in the simplex method, classified the techniques into four categories, and compared our results with those of HOPDM, CPLEX and Soplex by computational experiments. We also noted some implementing issues of preprocessing for the simplex method and the recovery of the optimal basis of the original problem from that of the preprocessed problem.

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A Study on a Analysis and Comparison of Preprocessing Technique for the Speech Compression (음성압축을 위한 전처리기법의 비교 분석에 관한 연구)

  • Jang, Kyung-A;Min, So-Yeon;Bae, Myung-Jin
    • Speech Sciences
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    • v.10 no.4
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    • pp.125-136
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    • 2003
  • Speech coding techniques have been studied to reduce the complexity and bit rate but also to improve the sound quality. CELP type vocoder, has used as a one of standard, supports the great sound quality even low bit rate. In this paper, the preprocessing of input speech to reduce the bit rate is the different with the conventional vocoder. The different kinds of parameter are used for the preprocessing so this paper is compared with theses parameters for finding the more appropriate parameter for the vocoder. The parameters are used to synthesize the speech not to encode or decode for coding technique so we proposed the simple algorithm not to have the influence on the processing time or the computation time. The parameters in used the preprocessing step are speaking rate, duration and PSOLA technique.

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Preprocessing Technique for Lane Detection Using Image Clustering and HSV Color Model (영상 클러스터링과 HSV 컬러 모델을 이용한 차선 검출 전처리 기법)

  • Choi, Na-Rae;Choi, Sang-Il
    • Journal of Korea Multimedia Society
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    • v.20 no.2
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    • pp.144-152
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    • 2017
  • Among the technologies for implementing autonomous vehicles, advanced driver assistance system is a key technology to support driver's safe driving. In the technology using the vision sensor having a high utility, various preprocessing methods are used prior to feature extraction for lane detection. However, in the existing methods, the unnecessary lane candidates such as cars, lawns, and road separator in the road area are false positive. In addition, there are cases where the lane candidate itself can not be extracted in the area under the overpass, the lane within the dark shadow, the center lane of yellow, and weak lane. In this paper, we propose an efficient preprocessing method using k-means clustering for image division and the HSV color model. When the proposed preprocessing method is applied, the true positive region is maximally maintained during the lane detection and many false positive regions are removed.

Preprocessing based Scheduling for Multi-Site Constraint Resources (전처리 방식의 복수지역 제약공정 스케줄링)

  • Hong, Min-Sun;Rim, Suk-Chul;Noh, Seung-J.
    • Journal of the Korean Operations Research and Management Science Society
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    • v.33 no.1
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    • pp.117-129
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    • 2008
  • Make-to-order manufacturers with multiple plants at multiple sites need to have the ability to quickly determine which plant will produce which customer order to meet the due date and minimize the transportation cost from the plants to the customer. Balancing the work loads and minimizing setups and make-span are also of great concern. Solving such scheduling problems usually takes a long time. We propose a new approach, which we call 'preprocessing', for resolving such complex problems. In preprocessing scheme, a 'good' a priori schedule is prepared and maintained using unconfirmed order information. Upon the confirmation of orders. the preprocessed schedule is quickly modified to obtain the final schedule. We present a preprocessing solution algorithm for multi-site constraint scheduling problem (MSCSP) using genetic algorithm; and conduct computational experiments to evaluate the performance of the algorithm.