• Title/Summary/Keyword: centroid algorithm

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A Successive Region Setting Algorithm Using Signal Strength Ranking from Anchor Nodes for Indoor Localization in the Wireless Sensor Networks (실내 무선 센서 네트워크에서의 측위를 위하여 고정 노드 신호들의 크기 순위를 사용한 순차적 구역 설정 알고리즘)

  • Han, Jun-Sang;Kim, Myoung-Jin
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.48 no.6
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    • pp.51-60
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    • 2011
  • Researches on indoor localization using the wireless sensor network have been actively carried out to be used for indoor area where GPS signal is not received. Computationally efficient WCL(Weighted Centroid Localization) algorithm is shown to perform relatively well. However, to get the best performance for WCL all the anchor nodes must send signal with power to cover 96% of the network. The fact that outside the transmission range of the fixed nodes drastic localization error occurs results in large mean error and deviation. Due to these problems the WCL algorithm is not easily applied for use in the real indoor environment. In this paper we propose SRS(Succesive Region Setting) algorithm which sequentially reduces the estimated location area using the signal strength from the anchor nodes. The proposed algorithm does not show significant performance degradation corresponding to transmission range of the anchor nodes. Simulation results show that the proposed SRS algorithm has mean localization error 5 times lower than that of the WCL under free space propagation environment.

Real-Time Automatic Target Tracking Using a Centroid of Moving Edges (이동경계의 무게중심에 의한 실시간 자동목표 추적)

  • 배정효;김남철
    • Proceedings of the Korean Institute of Communication Sciences Conference
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    • 1987.04a
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    • pp.42-45
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    • 1987
  • In this paper a target tracking algorithm of the centroid extraction from moving edges is proposed, It aims to avoid the difficulty of imahe segmentation in case of the centroid extraction from one frame. The performance of the proposed algorithmfor noisy and occluded images is discussed Finally it is also applied to a real time target tracker.

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A Performance Improvement Study On Hierarchical Clustering (Centroid Linkage) Using A Priority Queue (Priority Queue 를 이용한 Hierarchical Clustering (Centroid Linkage) 성능 개선)

  • Jeon, Yongkweon;Yoon, Sungroh
    • Proceedings of the Korea Information Processing Society Conference
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    • 2010.11a
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    • pp.1837-1838
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    • 2010
  • 기존 hierarchical clustering 은 Time complexity 와 space complexity 가 Large data set 을 clustering 하기에는 적당하지 못하며 이것을 일반 PC 의 메모리 내에서 해결하는데 어려움이 있다. 따라서 본 연구에서는 이러한 어려움을 극복하기 위해 기존 Hierarchical clustering 중 Centroid Linkage 에 새로운 Algorithm 을 제안하여 보다 적은 메모리를 사용하고 빠르게 처리하는 방법을 제안하고자 한다.

Localization using Centroid in Wireless Sensor Networks (무선 센서 네트워크에서 위치 측정을 위한 중점 기 법)

  • Kim Sook-Yeon;Kwon Oh-Heum
    • Journal of KIISE:Information Networking
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    • v.32 no.5
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    • pp.574-582
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    • 2005
  • Localization in wireless sensor networks is essential to important network functions such as event detection, geographic routing, and information tracking. Localization is to determine the locations of nodes when node connectivities are given. In this paper, centroid approach known as a distributed algorithm is extended to a centralized algorithm. The centralized algorithm has the advantage of simplicity. but does not have the disadvantage that each unknown node should be in transmission ranges of three fixed nodes at least. The algorithm shows that localization can be formulated to a linear system of equations. We mathematically show that the linear system have a unique solution. The unique solution indicates the locations of unknown nodes are capable of being uniquely determined.

Active Selection of Label Data for Semi-Supervised Learning Algorithm (준감독 학습 알고리즘을 위한 능동적 레이블 데이터 선택)

  • Han, Ji-Ho;Park, Eun-Ae;Park, Dong-Chul;Lee, Yunsik;Min, Soo-Young
    • Journal of IKEEE
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    • v.17 no.3
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    • pp.254-259
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    • 2013
  • The choice of labeled data in semi-supervised learning algorithm can result in effects on the performance of the resultant classifier. In order to select labeled data required for the training of a semi-supervised learning algorithm, VCNN(Vector Centroid Neural Network) is proposed in this paper. The proposed selection method of label data is evaluated on UCI dataset and caltech dataset. Experiments and results show that the proposed selection method outperforms conventional methods in terms of classification accuracy and minimum error rate.

A Study on the Comparison of 2-D Circular Object Tracking Algorithm Using Vision System (비젼 시스템을 이용한 2-D 원형 물체 추적 알고리즘의 비교에 관한 연구)

  • Han, Kyu-Bum;Kim, Jung-Hoon;Baek, Yoon-Su
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.7
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    • pp.125-131
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    • 1999
  • In this paper, the algorithms which can track the two dimensional moving circular object using simple vision system are described. In order to track the moving object, the process of finding the object feature points - such as centroid of the object, corner points, area - is indispensable. With the assumption of two-dimensional circular moving object, the centroid of the circular object is computed from three points on the object circumference. Different kinds of algorithms for computing three edge points - simple x directional detection method, stick method. T-shape method are suggested. Through the computer simulation and experiments, three algorithms are compared from the viewpoint of detection accuracy and computational time efficiency.

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Real-Time Automatic Target Tracking Using the Centroid Moving Edges (이동경계의 무게중심에 의한 실시간 자동목표추적)

  • Bae, Jeoung-Hyo;Kim, Nam-Chul
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.10
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    • pp.1234-1243
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    • 1988
  • In this paper, a target tracking algorithm using the centroid of moving edges is presented. It aims to avoid the difficulty of image segmentation in case of extracting the centroid from only one frame. The proposed algorithm can more easily segment the target than the conventional one in images with complex background. Moreover, it can track the target well when the target is occluded by an object. The result of applying it to a real-time target tracker is shown to be comparatively good.

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Intelligent Multimode Target Tracking Using Fuzzy Logic (퍼지 로직을 이용한 지능적인 다중모드 목표물 추적)

  • 조재수;박동조
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 1998.10a
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    • pp.468-473
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    • 1998
  • An intelligent multimode target tracking algorithm using fuzzy logic is presented. Multimode tracking represents a synergistic approach that utilizes a variety of tracking techniques(centroid, correlation, etc.) to overcome the limitations inherent in any single-mode tracker. The design challenge for this type of multimode tracker is the data fusion algorithm. designs for this algorithm are based on heuristic rather than analytical approaches. A correlation-tracking algorithm seeks to align the incoming target image with a reference in age of the target, but has a critical problem, so called drift phenomenon. In this paper we will suggest a robust correlation tracker with gradient preprocessor combined by centroid algorithm to overcome the drift problem.

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A New Item Recommendation Procedure Using Preference Boundary

  • Kim, Hyea-Kyeong;Jang, Moon-Kyoung;Kim, Jae-Kyeong;Cho, Yoon-Ho
    • Asia pacific journal of information systems
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    • v.20 no.1
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    • pp.81-99
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    • 2010
  • Lately, in consumers' markets the number of new items is rapidly increasing at an overwhelming rate while consumers have limited access to information about those new products in making a sensible, well-informed purchase. Therefore, item providers and customers need a system which recommends right items to right customers. Also, whenever new items are released, for instance, the recommender system specializing in new items can help item providers locate and identify potential customers. Currently, new items are being added to an existing system without being specially noted to consumers, making it difficult for consumers to identify and evaluate new products introduced in the markets. Most of previous approaches for recommender systems have to rely on the usage history of customers. For new items, this content-based (CB) approach is simply not available for the system to recommend those new items to potential consumers. Although collaborative filtering (CF) approach is not directly applicable to solve the new item problem, it would be a good idea to use the basic principle of CF which identifies similar customers, i,e. neighbors, and recommend items to those customers who have liked the similar items in the past. This research aims to suggest a hybrid recommendation procedure based on the preference boundary of target customer. We suggest the hybrid recommendation procedure using the preference boundary in the feature space for recommending new items only. The basic principle is that if a new item belongs within the preference boundary of a target customer, then it is evaluated to be preferred by the customer. Customers' preferences and characteristics of items including new items are represented in a feature space, and the scope or boundary of the target customer's preference is extended to those of neighbors'. The new item recommendation procedure consists of three steps. The first step is analyzing the profile of items, which are represented as k-dimensional feature values. The second step is to determine the representative point of the target customer's preference boundary, the centroid, based on a personal information set. To determine the centroid of preference boundary of a target customer, three algorithms are developed in this research: one is using the centroid of a target customer only (TC), the other is using centroid of a (dummy) big target customer that is composed of a target customer and his/her neighbors (BC), and another is using centroids of a target customer and his/her neighbors (NC). The third step is to determine the range of the preference boundary, the radius. The suggested algorithm Is using the average distance (AD) between the centroid and all purchased items. We test whether the CF-based approach to determine the centroid of the preference boundary improves the recommendation quality or not. For this purpose, we develop two hybrid algorithms, BC and NC, which use neighbors when deciding centroid of the preference boundary. To test the validity of hybrid algorithms, BC and NC, we developed CB-algorithm, TC, which uses target customers only. We measured effectiveness scores of suggested algorithms and compared them through a series of experiments with a set of real mobile image transaction data. We spilt the period between 1st June 2004 and 31st July and the period between 1st August and 31st August 2004 as a training set and a test set, respectively. The training set Is used to make the preference boundary, and the test set is used to evaluate the performance of the suggested hybrid recommendation procedure. The main aim of this research Is to compare the hybrid recommendation algorithm with the CB algorithm. To evaluate the performance of each algorithm, we compare the purchased new item list in test period with the recommended item list which is recommended by suggested algorithms. So we employ the evaluation metric to hit the ratio for evaluating our algorithms. The hit ratio is defined as the ratio of the hit set size to the recommended set size. The hit set size means the number of success of recommendations in our experiment, and the test set size means the number of purchased items during the test period. Experimental test result shows the hit ratio of BC and NC is bigger than that of TC. This means using neighbors Is more effective to recommend new items. That is hybrid algorithm using CF is more effective when recommending to consumers new items than the algorithm using only CB. The reason of the smaller hit ratio of BC than that of NC is that BC is defined as a dummy or virtual customer who purchased all items of target customers' and neighbors'. That is centroid of BC often shifts from that of TC, so it tends to reflect skewed characters of target customer. So the recommendation algorithm using NC shows the best hit ratio, because NC has sufficient information about target customers and their neighbors without damaging the information about the target customers.

A Study on Cooperative Based Location Estimation Algorithm in Wireless Sensor Networks (무선 센서 네트워크에서 상호 협력 기반 위치추정 알고리즘 연구)

  • Jeong, Seung-Heui;Lee, Hyun-Jae;Oh, Chang-Heon
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2008.05a
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    • pp.857-860
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    • 2008
  • In this paper, we proposed cooperative based localization algorithm for wireless sensor networks, which can estimate to unknown node position using received signal strength table set. The unknown nodes are monitor to RSS from neighbor nodes and exclude existence possibility area of sensor node in sensor field. Finally, we can calculate the centroid position for each unknown node with cooperative localization algorithm. Furthermore, these processes are applied iteratively about all nodes which is recorded to RSS table and can estimate for unknown nodes.

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