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101.
Customer Retention via Data Mining 总被引:6,自引:0,他引:6
``Customer Retention' is an increasingly pressing issue intoday's ever-competitive commercial arena. This is especially relevantand important for sales and services related industries. Motivated by areal-world problem faced by a large company, we proposed a solution thatintegrates various techniques of data mining, such as featureselection via induction, deviation analysis, and mining multipleconcept-level association rules to form an intuitive and novel approachto gauging customer loyalty and predicting their likelihood ofdefection. Immediate action triggered by these ``early-warnings'resulting from data mining is often the key to eventual customerretention. 相似文献
102.
Once segmentation of 3D surface data of a rock pile has been performed, the next task is to determine the visibility of the surface rocks. A region boundary-following algorithm that accommodates irregularly spaced 3D coordinate data is presented for determining this visibility. We examine 3D surface segmentations of laboratory rock piles and determine which regions in the segmentation correspond to entirely visible rocks, and which correspond to overlapped or partially visible rocks. This is a significant distinction as it allows accurate size determination of entirely visible rocks, separate handling of partially visible rocks, and prevents erroneous bias resulting from mishandling partially visible rocks as smaller entirely visible rocks. Literature review indicates that other rock pile sizing techniques fail to make this distinction. The rock visibility results are quantified by comparison to manual surface classifications of the laboratory piles and the size results are quantified by comparison to the sieve size. 相似文献
103.
S Lareau A Boyle R Deslauriers WJ Keon T Kroft RS Labow 《Canadian Metallurgical Quarterly》1993,27(6):1009-1014
OBJECTIVES: The effect of Mg2+ on the developed force and concentrations of high energy phosphate metabolites in isolated human atrial trabeculae has been investigated. METHODS: Human atrial trabeculae, obtained from right atrial appendages of patients undergoing cardiac surgery requiring cardiopulmonary bypass, were dissected at room temperature in modified Krebs-Henseleit buffer containing 1.2 or 16 mM Mg2+, mounted on muscle stands, and rewarmed to 34 degrees C in the same buffer. After 30 minutes, their mechanical function was assessed. At the end of the protocol, trabeculae were fast frozen for measurement of concentrations of metabolites of high energy phosphates. RESULTS: Trabeculae collected and rewarmed in 16 mM Mg2+ Krebs-Henseleit buffer showed significantly higher mean developed force (0.59(SEM 0.10) g, p < 0.01) than those rewarmed in 1.2 mM Mg2+ Krebs-Henseleit buffer (0.32(0.03) g). Trabeculae that had a developed force > or = 0.8 g, a resting force < or = 0.7 g, and a cross sectional area < or = 1 mm2 ("functional" trabeculae) were selected for further comparison. New reverse phase high performance liquid chromatography techniques developed for the analysis of small samples (0.5-5 mg dry weight) were used to measure nucleotide, nucleoside, and creatine compounds. Total adenylate (ATP+ADP+AMP) concentrations in trabeculae revived in the presence of 16 mM Mg2+ (15.4(1.1) mumol.g-1 dry weight) were significantly higher (p < 0.01) than in those revived with 1.2 mM Mg2+ (11.8(1.0) mumol.g-1), but lower (p < 0.01) than in trabeculae fast frozen immediately after removal from the patient (22.6(1.0) mumol.g-1). There were no significant differences in NAD and total creatine (phosphocreatine+creatine) concentrations between the three groups. CONCLUSIONS: The presence of high Mg2+ during the rewarming of human atrial trabecular preparations maintains a significantly higher developed force and a significantly higher total adenylate pool than does collection and rewarming with normal concentrations of Mg2+. 相似文献
104.
H.V. Jagadish Olga Kapitskaia Raymond T. Ng Divesh Srivastava 《The VLDB Journal The International Journal on Very Large Data Bases》2000,9(3):214-230
With the increasing importance of XML, LDAP directories, and text-based information sources on the Internet, there is an
ever-greater need to evaluate queries involving (sub)string matching. In many cases, matches need to be on multiple attributes/dimensions,
with correlations between the multiple dimensions. Effective query optimization in this context requires good selectivity
estimates. In this paper, we use pruned count-suffix trees (PSTs) as the basic data structure for substring selectivity estimation.
For the 1-D problem, we present a novel technique called MO (Maximal Overlap). We then develop and analyze two 1-D estimation
algorithms, MOC and MOLC, based on MO and a constraint-based characterization of all possible completions of a given PST.
For the k-D problem, we first generalize PSTs to multiple dimensions and develop a space- and time-efficient probabilistic algorithm
to construct k-D PSTs directly. We then show how to extend MO to multiple dimensions. Finally, we demonstrate, both analytically and experimentally,
that MO is both practical and substantially superior to competing algorithms.
Received April 28, 2000 / Accepted July 11, 2000 相似文献
105.
A laser induced fluorescence system, in combination with a glass-frit nebulizer and a photo-voltaic cell detector, is described for single molecule detection. The glass-frit nebulizer continuously generates a large number of droplets with an average droplet size of three micrometers in diameter. Rhodamine 6G molecules were detected at the 10(-12) M level. Concentrations 10(-12)-10(-10) M would provide mostly single molecules (0, 1, 2, 3, ...) in the individual droplets, as determined by Poisson distribution. 相似文献
106.
In recent years, there has been much debate about the concept of digital natives, in particular the differences between the digital natives' knowledge and adoption of digital technologies in informal versus formal educational contexts. This paper investigates the knowledge about educational technologies of a group of undergraduate students studying the course Introduction to eLearning at a university in Australia and how they adopt unfamiliar technologies into their learning. The study explores the 'digital nativeness' of these students by investigating their degree of digital literacy and the ease with which they learn to make use of unfamiliar technologies. The findings show that the undergraduates were generally able to use unfamiliar technologies easily in their learning to create useful artefacts. They need, however to be made aware of what constitutes educational technologies and be provided with the opportunity to use them for meaningful purposes. The self-perception measures of the study indicated that digital natives can be taught digital literacy. 相似文献
107.
T.H. Ng 《Information and Software Technology》2012,54(1):99-118
Context
Practitioners may use design patterns to organize program code. Various empirical studies have investigated the effects of pattern deployment and work experience on the effectiveness and efficiency of program maintenance. However, results from these studies are not all consistent. Moreover, these studies have not considered some interesting factors, such as a maintainer’s prior exposure to the program under maintenance.Objective
This paper aims at identifying what factors may contribute to the productivity of maintainers in the context of making correct software changes when they work on programs with deployed design patterns.Method
We performed an empirical study involving 118 human subjects with three change tasks on a medium-sized program to explore the possible effects of a suite of six human and program factors on the productivity of maintainers, measured by the time taken to produce a correctly revised program in a course-based setting. The factors we studied include the deployment of design patterns and the presence of pattern-unaware solutions, as well as the maintainer’s prior exposure to design patterns, the subject program and the programming language, and prior work experience.Results
Among the factors under examination, we find that the deployment of design patterns, prior exposure to the program and the presence of pattern-unaware solutions are strongly correlated with the time taken to correctly complete maintenance tasks. We also report some interesting observations from the experiment.Conclusion
A new factor, namely, the presence of pattern-unaware solutions, contributes to the efficient completion of maintenance tasks of programs with deployed design patterns. Moreover, we conclude from the study that neither prior exposure to design patterns nor prior exposure to the programming language is supported by sufficient evidences to be significant factors, whereas the subjects’ exposure to the program under maintenance is notably more important. 相似文献108.
This paper presents a disturbance decoupled fault reconstruction (DDFR) scheme using cascaded sliding mode observers (SMOs). The processed signals from a SMO are found to be the output of a fictitious system which treats the faults and disturbances as inputs; the ‘outputs’ are then fed into the next SMO. This process is repeated until the attainment of a fictitious system which satisfies the conditions that guarantee DDFR. It is found that this scheme is less restrictive and enables DDFR for a wider class of systems compared to previous work when only one or two SMOs were used. This paper also presents a systematic routine to check for the feasibility of the scheme and to calculate the required number of SMOs from the outset and also to design the DDFR scheme. A design example verifies its effectiveness. 相似文献
109.
The lead free Sn–Ag–y%Cu (y = 0.0, 0.5, 1.0 and 2.0) interconnect interfacial microstructures and the microstructure evolution under thermal treatment (isothermal aging, 150 °C/1000 h) were studied in detail by using surface microetching microscopy and cross section microscopy. The corresponding mechanical and reliability behaviors were evaluated by performing shear test and fracture mode analysis before and after the thermal treatment. The results indicate: (i) The interconnects could have different microstructures and intermetallic compound (IMC), depending on the Cu content. The Cu–Sn IMC could have microstructures that were clusters or protrusion-like, Augustine grass leaf-like, scissor-like, tweezers-like, etc. (ii) Ag3Sn IMCs were not observed at time zero for any interconnect groups, but they occurred after the aging for all groups. The Ag3Sn IMC could have different microstructures, again depending on Cu content. For low Cu content, the Ag3Sn IMCs were granules or nodules; for higher Cu content, Ag3Sn IMCs were plate-like. (iii) The growth of Ag3Sn plates was promoted by the growth of Cu–Sn IMCs, but indirectly linked to the Cu content. (iv) High Cu content (1.0 wt% and higher) could degrade the mechanical and reliability performances of the LF interconnect by providing a brittle joint, which was mainly achieved through the substantial growth of Cu–Sn IMCs and Ag3Sn plates. 相似文献
110.
This letter presents the design and implementation of a dual-modulus (64/65) prescaler based upon the phase-switching technique. Low power consumption is achieved by using one dynamic flip-flop in the full-speed divide-by-four circuit and no power-hungry synchronizing circuits to tackle the glitch problem. The proposed design is fabricated using 0.35-/spl mu/m standard CMOS process and is measured to operate from 2.08-2.66GHz with power dissipation of less than 1mW. 相似文献