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71.
With the increasing popularity of cloud computing, there is increased motivation to outsource data services to the cloud to save money. An important problem in such an environment is to protect user privacy while querying data from the cloud. To address this problem, researchers have proposed several techniques. However, existing techniques incur heavy computational and bandwidth related costs, which will be unacceptable to users. In this paper, we propose a cooperative private searching (COPS) protocol that provides the same privacy protections as prior protocols, but with much lower overhead. Our protocol allows multiple users to combine their queries to reduce the querying cost while protecting their privacy. Extensive evaluations have been conducted on both analytical models and on a real cloud environment to examine the effectiveness of our protocol. Our simulation results show that the proposed protocol reduces computational costs by 80% and bandwidth cost by 37%, even when only five users query data. 相似文献
72.
This study examined whether evaluations (agreements, disagreements), knowledge content (new ideas, justifications), or social cues (SCs) in recent messages affected a current message’s positive or negative SC during asynchronous, online discussions. Using statistical discourse analysis, we modeled 894 messages by 183 participants on 60 high school mathematics topics (typically eight people posted per topic) on a mathematics problem solving website not connected to any class or school. Results showed that recent agreements increased the likelihood of positive SC, whereas justifications reduced it. Disagreements increased the likelihood of negative SC, whereas new ideas reduced it. Meanwhile, recent positive or negative SCs did not affect the likelihood of a subsequent SC. Together, these results suggest that judicious use of positive SCs rather than negative SCs during disagreements can help students both construct knowledge and maintain social relationships. 相似文献
73.
Du-Ming Tsai Ming-Chun Chen Wei-Chen Li Wei-Yao Chiu 《Machine Vision and Applications》2012,23(5):869-886
In this paper, we propose a fast regularity measure for defect detection in non-textured and homogeneously textured surfaces, with specific emphasis on ill-defined subtle defects. A small neighborhood window of proper size is first chosen and they slide over the entire inspection image in a pixel-by-pixel basis. The regularity measure for each image patch enclosed in the window is then derived from the eigenvalues of the covariance matrix formed by the variance–covariance of the x- and y-coordinates with the pixel gray levels as the weights for all pixel points in the window. The two eigenvalues of the weighted covariance matrix will be approximately the same when the image patch contains only a homogeneous region, whereas the two eigenvalues will be relatively different if the image patch in the window contains a defect. The smaller eigenvalue of the covariance matrix is then used as the regularity measure. The integral image technique is introduced to the computation of the regularity measure so that it is invariant to the neighborhood window size. The proposed method uses only one single discrimination feature for defect detection. It avoids the use of complicated classifiers in a high-dimensional feature space, and requires no learning process from a set of defective and defect-free training samples. Experimental results on a variety of material surfaces found in industry, including textured images of plastic surfaces and leather and non-textured images of backside solar wafers and LCD backlight panels, have shown the effectiveness of the proposed regularity measure for surface defect detection. It is computationally very fast, and takes only 0.032 s for a 400 × 400 image on a Pentium 3.00?GHz personal computer. In a test set of 73 backside solar wafer images involving 53 defect-free and 20 defective samples, the proposed regularity measure can correctly identify all the test images. 相似文献
74.
Singa Wang ChiuYuan-Shyi Peter Chiu Jyh-Chau Yang 《Expert systems with applications》2012,39(3):2578-2583
This paper combines an alternative multi-delivery policy into an imperfect economic production quantity (EPQ) model with partial rework, with the purpose of reducing supplier’s stock holding cost. We extend the problem examined by Chiu et al. [Chiu, Y.-S. P, Chiu, S. W., Li, C.-Y., & Ting, C.-K. (2009). Incorporating multi-delivery policy and quality assurance into economic production lot size problem. Journal of Scientific and Industrial Research, 68(6), 505-512] by considering an n + 1 delivery policy in lieu of n multi-delivery plan for the specific EPQ model with partial rework. Under such a policy, an initial delivery of perfect (finished) items is distributed to customer for satisfying product demand during manufacturer’s regular production time and rework time. At the end of rework, fixed quantity n installments of the finished products are delivered to customer at a fixed interval of time. As a result, a closed-form optimal replenishment batch size solution to the problem is obtained. A numerical example with analysis and comparison is provided to show practical usage of the proposed model and demonstrate its significant savings in stock holding cost. 相似文献
75.
Chiu Liu 《Canadian Metallurgical Quarterly》2005,131(2):161-166
Van der Waals force between neutral molecules is employed to characterize the interaction among molecules in asphalt cement. Several important consequences emerge from the consideration. The brittle strength of the asphalt binder is shown to be linked to the well depth of the Van der Waals potential and the mesoscopic cracks present within the asphalt binder. Moreover, the elastic modulus of asphalt binder is analytically related to the potential well depth. The strength of the asphalt concrete (AC) is estimated by considering aggregate surface characteristics and the adhesion strength between asphaltenes or resins and molecules of aggregates. These predictions can help design asphalt concrete pavement. Formulas for predicting the binder strength and the interfacial breaking strength between aggregates and binders are derived. These results are supported by reported data. Furthermore, an analytic expression for the strength of AC is given at temperature below the AC glass transition point. 相似文献
76.
A case-based expert support system for due-date assignment in a wafer fabrication factory 总被引:3,自引:1,他引:3
Chaochang Chiu Pei-Chann Chang Nan-Hsing Chiu 《Journal of Intelligent Manufacturing》2003,14(3-4):287-296
Owing to the complexity of wafer fabrication, the traditional human approach to assigning due-date is imprecise and very prone to failure, especially when the shop status is dynamically changing. Therefore, assigning a due date to each order becomes a challenge to the production planning and scheduling staff. Since most production orders are similar to those previously manufactured, the case based reasoning (CBR) approach provides a suitable means for solving the due-date assignment problem. This research proposes a CBR approach that employs the k-nearest neighbors concept with dynamic feature weights and non-linear similarity functions. The test results show that the proposed approach can more accurately predict order due dates than other approaches. 相似文献
77.
With the development of new technology and use of lightweight material such as composite laminates, new methods must be developed for in situ structural health monitoring of these materials. This paper introduces an approach for the detection of delamination present in GLARE aluminium specimens. The approach is based on the change in group velocity of Lamb waves with frequency–thickness product as the determinant parameter for the detection of delamination. Two methods are applied: a surface contact method, which utilises a wedge probe tuned to excite a single Lamb mode, and the embedded PZT method, which involves incorporating lead zirconate titanate (PZT) elements in the glass fibre reinforced resin matrix during the manufacture of the GLARE aluminium specimens. It was found that both methods enabled the detection of delaminations in the GLARE aluminium specimens, within certain limits, which are stated. 相似文献
78.
A bibliometric analysis was performed to assess the quantitative trend of Patent Ductus Arteriosus (PDA) treatment research,
including intravenous injection of indomethacin and surgery. The documents studied were retrieved from the Science Citation Index (SCI) for the period from 1991 to 2002. The publication pattern concerning authorship, collaboration, original countries,
citation frequency, document type, language of publication, distribution of journals, page count and the most frequently cited
papers were performed. The results indicated that either treatment was not the recent emphasis of PDA research. The publishing
countries of both treatments have also denoted that these researches were mostly done in Europe and North America. Both surgery
and drug treatments had few international collaboration papers. English was the dominant language, and collaboration of two
to six authors was the most popular level of co-authorship.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
79.
80.
In this study the fracture mechanics parameters, including the strain energy release rate, the stress intensity factors and
phase angles, along the curvilinear front of a three-dimensional bimaterial interface crack in electronic packages are considered
by using finite element method with the virtual crack closure technique (VCCT). In the numerical procedure normalized complex
stress intensity factors and the corresponding phase angles (Rice, J Appl Mech 55:98–103, 1988) are calculated from the crack
closure integrals for an opening interface crack tip. Alternative procedures are also described for the cases of crack under
inner pressure and crack faces under large-scale contact. Validation for the procedure is performed by comparing numerical
results to analytical solutions for the problems of interface crack subjected to either remote tension or mixed loading. The
numerical approach is then applied to study interface crack problems in electronic packages. Solutions for semi-circular surface
crack and quarter-circular corner crack on the interface of epoxy molding compound and silicon die under uniform temperature
excursion are presented. In addition, embedded corner delaminations on the interface of silicon die and underfill in flip-chip
package under thermomechanical load are investigated. Based on the distribution of the fracture mechanics parameters along
the interface crack front, qualitative predictions on the propensity of interface crack propagation under thermomechanical
loads are given. 相似文献