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951.
A co-location pattern is a group of spatial features/events that are frequently co-located in the same region. For example, human cases of West
Nile Virus often occur in regions with poor mosquito control and the presence of birds. For co-location pattern mining, previous
studies often emphasize the equal participation of every spatial feature. As a result, interesting patterns involving events
with substantially different frequency cannot be captured. In this paper, we address the problem of mining co-location patterns with rare spatial features. Specifically, we first propose a new measure called the maximal participation ratio (maxPR) and show that a co-location pattern with a relatively high maxPR value corresponds to a co-location pattern containing
rare spatial events. Furthermore, we identify a weak monotonicity property of the maxPR measure. This property can help to
develop an efficient algorithm to mine patterns with high maxPR values. As demonstrated by our experiments, our approach is
effective in identifying co-location patterns with rare events, and is efficient and scalable for large-scale data sets.
相似文献
Hui XiongEmail: |
952.
One-leg methods and linear multistep methods are two class of important numerical methods applied to stiff initial value
problems of ordinary differential equations. The purpose of this paper is to present some convergence results of A-stable
one-leg and linear multistep methods for one-parameter multiply stiff singular perturbation problems and their corresponding
reduced problems which are a class of stiff differential-algebraic equations.
Received April 14, 2000; revised June 30, 2000 相似文献
953.
一体化水下航行器仿真系统软件设计 总被引:5,自引:1,他引:4
文章研究了水下自动航行器仿真系统的一体化软件设计原则和方法,给出了仿真系统的软件结构及其关键的设计技术。 相似文献
954.
955.
本文从互连网发展的趋势入手,对路径模式发掘进行了研究。先简要介绍数据库发掘的概况及网上数据发掘的特点,后结合关联法和组合概率法,并以算法和实例详细对之进行分析。 相似文献
956.
Feature extraction in carpal-bone analysis 总被引:4,自引:0,他引:4
Hand-bone analysis with image processing techniques using a digital radiograph can be used to assess skeletal age. The analysis consists of two steps: phalangeal and carpal bone analysis. The carpal bone analysis is discussed. First, the carpal bone region of interest (CROI) is defined using a standard thresholding technique to separate the hand from the background. Then, a dynamic thresholding method with variable window sizes is used to differentiate between the bones and the soft tissue. Next, the radius, ulna, and metacarpals intersecting the borders of the CROI are removed by using mathematical morphology. Finally, all objects included in the corrected CROI are separated and described in terms of features. These features describe the size, shape, and location and include some gray-scale pixel value information. On the basis of this analysis, the separation of the noncarpal bone objects from the carpal bone is possible. The feature selection step removes features of low discriminant power and reduces the space dimension. The remaining carpal bone parameters are used for further analysis leading to skeletal age assessment. 相似文献
957.
M Pazianas M Zaidi CL Huang BS Moonga VS Shankar 《Canadian Metallurgical Quarterly》1993,192(3):1100-1105
We demonstrated previously that osteoclasts possess a divalent cation-sensitive "receptor", the Ca2+ receptor. Activation of the Ca2+ receptor by the surrogate cation Ni2+ was shown to elicit an increase in cytosolic [Ca2+] to a peak value followed by an exponential decline. In the present study we examined the influence of surface membrane voltage on the kinetics of Ca2+ receptor inactivation. The K+ ionophore, valinomycin was applied to intercept the declining phase of the cytosolic [Ca2+] transient elicited by application of between 50 microM- and 5 mM-[Ni2+]. This resulted in a sustained elevation of cytosolic [Ca2+] or even a 'hump' followed by a gradual decline. Such a kinetic alteration persisted in a Ca(2+)-free solution, but was abolished in high extracellular [K+] (105 mM). Thus, we demonstrate for the first time to our knowledge, a modulatory effect of membrane potential on the function of the osteoclast Ca2+ receptor. 相似文献
958.
959.
Huang S. Ren W. Chan S.C. 《IEEE transactions on systems, man, and cybernetics. Part A, Systems and humans : a publication of the IEEE Systems, Man, and Cybernetics Society》2000,30(6):661-673
We present a technology which allows manually controlled and automatically controlled vehicles to co-exist, thereby reducing much of the cost and infrastructure requirements in highway automation. An autonomous vehicle driving system (AVDS) is presented which only uses information from vehicle sensors, thereby eliminating the requirement that vehicles communicate with one another. This format allows gradual market penetration of AVDS, which makes the technology attractive from a systems implementation standpoint. To evaluate the performance of the mixed traffic, we simulate manual and automated vehicles together and show that our AVDS can lead to potentially large gains in capacity and smoother flow without the loss of safety 相似文献
960.