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Sequence-based clustering for Web usage mining: A new experimental framework and ANN-enhanced K-means algorithm 总被引:1,自引:0,他引:1
We develop a general sequence-based clustering method by proposing new sequence representation schemes in association with Markov models. The resulting sequence representations allow for calculation of vector-based distances (dissimilarities) between Web user sessions and thus can be used as inputs of various clustering algorithms. We develop an evaluation framework in which the performances of the algorithms are compared in terms of whether the clusters (groups of Web users who follow the same Markov process) are correctly identified using a replicated clustering approach. A series of experiments is conducted to investigate whether clustering performance is affected by different sequence representations and different distance measures as well as by other factors such as number of actual Web user clusters, number of Web pages, similarity between clusters, minimum session length, number of user sessions, and number of clusters to form. A new, fuzzy ART-enhanced K-means algorithm is also developed and its superior performance is demonstrated. 相似文献
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Organic Electronics: Self‐Assembled,Millimeter‐Sized TIPS‐Pentacene Spherulites Grown on Partially Crosslinked Polymer Gate Dielectric (Adv. Funct. Mater. 24/2015) 下载免费PDF全文
Hocheon Yoo Hyun Ho Choi Tae Joo Shin Taiuk Rim Kilwon Cho Sungjune Jung Jae‐Joon Kim 《Advanced functional materials》2015,25(24):3795-3795
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Yu-Jin Choi Seohee Park Won-Jin Yoon Seok-In Lim Jahyeon Koo Dong-Gue Kang Sungjune Park Namil Kim Kwang-Un Jeong 《Advanced materials (Deerfield Beach, Fla.)》2020,32(39):2003980
The development of smart inks that change color and transparency in response to external stimuli is very important for various fields, from modern art to safety and anticounterfeiting technology. A uniaxially oriented diacetylene thin film on a macroscopic area is obtained by coating, self-assembling and topochemical photopolymerizing of imidazolium-functionalized diacetylenes (M-DA and T-DA) and 4,6-decadiyne ink (70 wt%:20 wt%:10 wt%) exhibiting a lyotropic smectic A liquid-crystalline phase at room temperature. The color and transparency of letters and symbols written with the DA-based secret inks change reversibly from blue to red as well as from colorless transparent to black opaque depending on the temperature and polarization axis. A secret code written with thermoresponsive and polarization-dependent secret inks consisting of imidazolium-functionalized diacetylenes is successfully deciphered by wearing polaroid glasses and holding a burning torch. 相似文献
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Kyusuk Han Youngjoon Seo Sungjune Yoon James J. Park Taeshik Shon 《Journal of Network and Computer Applications》2011,34(6):1903-1907
Vertical handoff is one of the most important issues in the heterogeneous networks. While Lee et al. introduced a selective advance reservations and resource-aware handoff direction (SARAH) mechanism in order to provide a fast and efficient handoff with combination of layer 2 (L2) and layer 3 (L3) communications, there was a drawback that there was no consideration of handoff between heterogeneous network. In this paper, we improve the mechanism by providing security functions such as the neighbor-mapping server that binds IP address and MAC address with security support. At first, we discuss security issues in SARAH and proposed enhanced protocol. Finally, we show simple implementation results of our design in order to verify the practical aspects of our design. 相似文献
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Owing to the increasing environmental and climate changes globally, there is an increasing interest in the molecular-level understanding of environmental organic compound mixtures, that is, the pursuit of complete and detailed knowledge of the chemical compositions and related chemical reactions. Environmental organic molecule mixtures, including those in air, soil, rivers, and oceans, have extremely complex and heterogeneous chemical compositions. For their analyses, ultrahigh-resolution and sub-ppb level mass accuracy, achievable using Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), are important. FT-ICR MS has been successfully used to analyze complex environmental organic molecule mixtures such as natural, soil, particulate, and dissolved organic matter. Despite its success, many limitations still need to be overcome. Sample preparation, ionization, structural identification, chromatographic separation, and data interpretation are some key areas that have been the focus of numerous studies. This review describes key developments in analytical techniques in these areas to aid researchers seeking to start or continue investigations for the molecular-level understanding of environmental organic compound mixtures. 相似文献
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A fundamental study of pile-soil systems subjected to lateral loads in clay soil was conducted by using experimental tests and a lateral load-transfer approach. The emphasis was on an improved wedge failure model developed by considering three-dimensional combination forces and a new hyperbolic p-y criterion. A framework for determining the p-y curve on the basis of both theoretical analysis and experimental load test results is proposed. The proposed p-y method is shown to be capable of predicting the behavior of a large-diameter pile under lateral loading. The proposed p-y curves with an improved wedge model are more appropriate and realistic for representing a pile-soil interaction for laterally loaded piles in clay than the existing p-y method. 相似文献
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Inkjet-printed resistors with resistance values varying over five orders of magnitude were demonstrated on a flexible substrate. The resistivity of printed lines of poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) was altered by using different ink formulations and by employing an over-print technique, while the length of the printed resistor line remained unchanged. This technique was then applied to fabricate a printed read-only memory device that consisted of an array of resistors. The concept of printing reliable, visually identical resistors with controlled resistance values provides an important building block for low cost, printed electronic circuit applications. 相似文献