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101.
Solving multi-granularity temporal constraint networks 总被引:6,自引:0,他引:6
Many problems in scheduling, planning, and natural language understanding have been formulated in terms of temporal constraint satisfaction problems (TCSP). These problems have been extensively investigated in the AI literature providing effective solutions for some fragments of the general model. Independently, there has been an effort in the data and knowledge management research community for the formalization of the concept of time granularity and for its applications. This paper considers a framework for integrating the notion of time granularity into TCSP, and investigates the problems of consistency and network solution, which, in this context, involve complex manipulation of the periodic sets representing time granularities. A sound and complete algorithm for consistency checking and for deriving a solution is presented. The paper also investigates the algorithm's computational complexity and several optimization techniques specific to the multi-granularity context. An application to e-commerce workflows illustrates the benefits of the framework and the need for specific reasoning tools. 相似文献
102.
Privacy in geo-social networks: proximity notification with untrusted service providers and curious buddies 总被引:2,自引:0,他引:2
Sergio Mascetti Dario Freni Claudio Bettini X. Sean Wang Sushil Jajodia 《The VLDB Journal The International Journal on Very Large Data Bases》2011,20(4):541-566
A major feature of the emerging geo-social networks is the ability to notify a user when any of his friends (also called buddies)
happens to be geographically in proximity. This proximity service is usually offered by the network itself or by a third party service provider (SP) using location data acquired from the
users. This paper provides a rigorous theoretical and experimental analysis of the existing solutions for the location privacy
problem in proximity services. This is a serious problem for users who do not trust the SP to handle their location data and
would only like to release their location information in a generalized form to participating buddies. The paper presents two
new protocols providing complete privacy with respect to the SP and controllable privacy with respect to the buddies. The
analytical and experimental analysis of the protocols takes into account privacy, service precision, and computation and communication
costs, showing the superiority of the new protocols compared to those appeared in the literature to date. The proposed protocols
have also been tested in a full system implementation of the proximity service. 相似文献
103.
Maureen T. Ross Rena Cruz Trent L. Brooks-Richards Louise M. Hafner Sean K. Powell Maria A. Woodruff 《Virtual and Physical Prototyping》2018,13(4):255-265
Congenital facial anomalies, such as microtia (malformation of the external ear), lead to significant psychosocial effects starting from early childhood. Three-dimensional (3D) scanning and advanced manufacturing are being investigated as a cheaper and more personalised method of fabricating reconstructive treatments for patients compared to traditional approaches. To date, most case studies have used expensive 3D scanners, yet, there is potential for low-cost devices to provide comparable results. This study aimed to investigate these different approaches. Both ears of 16 adult participants were scanned with three devices: Artec Spider (Artec Group), Intel® RealSense? (Intel), and the Apple iPhone® 7 (Apple Inc.) combined with photogrammetry using 90, 60 and 30 photographs. The scanning time, processing time, accuracy, completeness, resolution and repeatability of each technique were assessed using the Artec Spider as a reference scanner. Our results show that the iPhone had the longest processing time however, this decreased nine-fold when reducing the number of photos from 90 to 30. There was no significant difference in the accuracy, completeness or repeatability of the iPhone scans with 90 photographs (1.4?±?0.6?mm, 79.9%, 1.0?±?0.1?mm), 60 photographs (1.2?±?0.2, 79.3%, 0.9?±?0.2?mm) or 30 photographs (1.2?±?0.3?mm, 74.3%, 1.0?±?0.2?mm). The Intel RealSesne performed significantly worse in each parameter (1.8?±?03?mm; 46.6%, 1.4?±?0.5). Additionally, the RealSense had significantly lower resolution with not enough detail captured for the application. These results demonstrate that the ear can be accurately 3D scanned using iPhone photographs. We would recommend capturing between 30 and 60 photographs of the ear to create a scan that is accurate but without the downfall of long processing time. Using these methods we aim to provide a more comfortable setting for the patient and a lower-cost and more personalised ear prosthesis. 相似文献
104.
Hyunkyu Lee Pauline L. Baniqued Joshua Cosman Sean Mullen Edward McAuley Joan Severson Arthur F. Kramer 《Computers in human behavior》2012
Many studies conducted in a laboratory or university setting are limited by funding, personnel, space, and time constraints. In the present study, we introduce a method of data collection using a mobile application that circumvents these typical experiment administration issues. Using the application, we examined cross-sectional age differences in cognitive function. We obtained data from more than 15,000 participants and replicated specific patterns of age-related differences in cognition. Using a subset of these participants, we also examined the processing speed account of age-related cognitive differences, and the association of exercise and leisure activity with cognitive function across the lifespan. We discuss the relative advantages and disadvantages of data collection with a mobile application, and provide recommendations for the use of this method in research. 相似文献
105.
Effects of 3‐D microwell culture on initial fate specification in human embryonic stem cells 下载免费PDF全文
Cheston Hsiao Matthew Tomai Jeremy Glynn Sean P. Palecek 《American Institute of Chemical Engineers》2014,60(4):1225-1235
Several studies have demonstrated that three‐dimensional (3‐D) culture systems influence human embryonic stem cell (hESC) phenotypes and fate choices. However, the effect that these microenvironmental changes have on signaling pathways governing hESC behaviors is not well understood. Here, a 3‐D microwell array was used to investigate differences in activation of developmental pathways between 2‐D and 3‐D cultures of both undifferentiated hESCs and hESCs undergoing initial differentiation in embryoid bodies (EBs). An increased induction into mesoderm and endoderm and differences in expression of genes from multiple signaling pathways that regulate development, including Wnt/β‐catenin, TGF‐β superfamily, Notch, and FGF during EB‐mediated differentiation were observed in 3‐D microwells as compared with the 2‐D substrates. In undifferentiated hESCs, differences in epithelial‐mesenchymal transition phenotypes and the TGFβ/BMP pathway between cultures in 3‐D and 2‐D were also observed. These results illustrate that 3‐D culture influences multiple pathways that may regulate the differentiation trajectories of hESCs. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1225–1235, 2014 相似文献
106.
Terry D. Humphries Keelie T. Munroe Tamara M. DeWinter Craig M. Jensen G. Sean McGrady 《International Journal of Hydrogen Energy》2013
Aluminum hydride (alane; AlH3) has been identified as a leading hydrogen storage material by the US Department of Energy. With a high gravimetric hydrogen capacity of 10.1 wt.%, and a hydrogen density of 1.48 g/cm3, AlH3 decomposes cleanly to its elements above 60 °C with no side reactions. This study explores in detail the thermodynamic and spectroscopic properties of AlH3; in particular the α, α′ and γ polymorphs, of which α′-AlH3 is reported for the first time, free from traces of other polymorphs or side products. Thermal analysis of α-, α′-, and γ-AlH3 has been conducted, using DSC and TGA methods, and the results obtained compared with each other and with literature data. All three polymorphs were investigated by 1H MAS-NMR spectroscopy for the first time, and their 27Al MAS-NMR spectra were also measured and compared with literature values. AlH3·nEt2O has also been studied by 1H and 27Al MAS-NMR spectroscopy and DSC and TGA methods, and an accurate decomposition pathway has been established for this adduct. 相似文献
107.
Sean Poust James Piety Dr. Arren Bar‐Even Dr. Catherine Louw Prof. Dr. David Baker Prof. Dr. Jay D. Keasling Prof. Dr. Justin B. Siegel 《Chembiochem : a European journal of chemical biology》2015,16(13):1950-1954
An enzyme that catalyzes the formose reaction, termed “formolase”, was recently engineered through a combination of computational protein design and directed evolution. We have investigated the kinetic role of the computationally designed residues and further characterized the enzyme's product profile. Kinetic studies illustrated that the computationally designed mutations were synergistic in their contributions towards enhancing activity. Mass spectrometry revealed that the engineered enzyme produces two products of the formose reaction—dihydroxyacetone and glycolaldehyde—with the product profile dependent on the formaldehyde concentration. We further explored the effects of this product profile on the thermodynamics and yield of the overall carbon assimilation from the formolase pathway to help guide future efforts to engineer this pathway. 相似文献
108.
Cunningham Sean D.; Thomas Pamela Dixon; Warschausky Seth 《Canadian Metallurgical Quarterly》2007,52(3):331
Objective: To examine gender differences in the peer relations of children with congenital neurodevelopmental conditions (NDC). Participants: Thirty-four children with cerebral palsy or spina bifida and 41 typically developing (TD) children, ages 6-12. Measures: Personality Inventory for Children-Second Edition (PIC-2), Social Network Inventory for Children-Child Version, and the Friendship Quality Questionnaire-Revised (FQQ-R). Results: Children with NDC report smaller social networks and lower quality of friendships than TD peers. Group × Gender interaction effects were not significant. Conclusion: Prior to adolescence, the social differences and risks associated with NDC do not appear to be gender specific. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
109.
110.
Shi-Wen Jiang Haibin Chen Sean Dowdy Alex Fu John Attewell Eleftheria Kalogera Ronny Drapkin Karl Podratz Russell Broaddus Jinping Li 《International journal of molecular sciences》2013,14(11):22655-22677
We investigated the HE4 variant-specific expression patterns in various normal tissues as well as in normal and malignant endometrial tissues. The relationships between mRNA variants and age, body weight, or survival are analyzed. ICAT-labeled normal and endometrial cancer (EC) tissues were analyzed with multidimensional liquid chromatography followed by tandem mass spectrometry. Levels of HE4 mRNA variants were measured by real-time PCR. Mean mRNA levels were compared among 16 normal endometrial samples, 14 grade 1 and 14 grade 3 endometrioid EC, 15 papillary serous EC, and 14 normal human tissue samples. The relationship between levels of HE4 variants and EC patient characteristics was analyzed with the use of Pearson correlation test. We found that, although all five HE4 mRNA variants are detectable in normal tissue samples, their expression is highly tissue-specific, with epididymis, trachea, breast and endometrium containing the highest levels. HE4-V0, -V1, and -V3 are the most abundant variants in both normal and malignant tissues. All variants are significantly increased in both endometrioid and papillary serous EC, with higher levels observed in grade 3 endometrioid EC. In the EC group, HE4-V1, -V3, and -V4 levels inversely correlate with EC patient survival, whereas HE4-V0 levels positively correlate with age. HE4 variants exhibit tissue-specific expression, suggesting that each variant may exert distinct functions in normal and malignant cells. HE4 levels appear to correlate with EC patient survival in a variant-specific manner. When using HE4 as a biomarker for EC management, the effects of age should be considered. 相似文献