159 research outputs found
Multivariate Gaussian Network Structure Learning
We consider a graphical model where a multivariate normal vector is
associated with each node of the underlying graph and estimate the graphical
structure. We minimize a loss function obtained by regressing the vector at
each node on those at the remaining ones under a group penalty. We show that
the proposed estimator can be computed by a fast convex optimization algorithm.
We show that as the sample size increases, the estimated regression
coefficients and the correct graphical structure are correctly estimated with
probability tending to one. By extensive simulations, we show the superiority
of the proposed method over comparable procedures. We apply the technique on
two real datasets. The first one is to identify gene and protein networks
showing up in cancer cell lines, and the second one is to reveal the
connections among different industries in the US.Comment: 30 pages, 17 figures, 3 table
Instructional changes instigated by university faculty during the COVID-19 pandemic: the effect of individual, course and institutional factors
The purpose of this study was to investigate instructional changes made by faculty for emergency online teaching necessitated by the COVID-19 pandemic, and hence to explore key factors related to those changes from an ecological systems perspective. Data on various individual, course, and institutional factors and instructional change variables were collected from 201 educators at higher education institutions. Results revealed that the level of instructional changes made by faculty was on average between substituting their existing course for an online one with some functional improvement (augmentation-level 3) and critical course redesign (modification-level 4), but that educators did not reach the level of the creation of new tasks which were previously inconceivable (redefinition-level 5). The biggest instructional change was found to be in teaching behaviors, followed by technology use, with only small changes in beliefs about online teaching. Factors that most highly correlated with instructional change were individual educators technology acceptance and innovation propensity, media synchronicity of the course, and the fidelity of institutional support. Recommendations are provided to aid strategic coping by universities facing a major crisis, with insights that may ultimately improve the quality of higher education in non-crisis contexts.This study was supported by the Ministry of Education (NRF-2020S1A5A8041947) and the Ministry of Science and ICT
(NRF-2021R1F1A1056465) of the Republic of Korea, and the National Research Foundation of Korea, and the 2019–2022
Grant-in Aid for Scientifc Research (Kakenhi) from the Japan Society for the Promotion of Society
Investigation of Advanced Cathode Contacting Solutions in SOFC
Contacting solutions for air electrode in Solid Oxide Cells stacks often implement a ceramic paste made of electronic conducting perovskite, comparable or same as the electro-active material. This contacting layer, is applied in a green state by wet-powder-spray or screen-printing, and in situ fired during stack commissioning. The low level of necking between ceramic particles causes increased ohmic losses. Moreover the shrinkage usually observed during long term operation in temperature of this layer, due to sintering effect, lead to cracks and contact losses which hinder the cell performance. Increasing cell’s footprint, performance and lifetime at the stack level requires appropriate contacting solution.
In this paper we reports the investigation of a new advanced monolithic contacting solution, easy to handle, soft and flexible, highly porous and highly conductive. Two different compositions have been investigated, with respect of their compatibility with Crofer (SEM, XRD). In addition, solid oxide cells contacted with this solution as well as with a ceramic paste have also been electrochemically tested up to 1000 hours in order to compare and assess the impact of this contacting solution on cell’s performance. Results will be presented and discussed
Difference in the epidemiologic and clinical characteristics by age groups of the children who visited a hand center emergency department with a hand injury requiring surgery
Purpose We aimed to describe the difference in the epidemiologic and clinical characteristics by age groups of the children with hand injuries requiring surgery who visited the emergency department (ED) of a community hospital that runs a hand center. Methods We reviewed 388 consecutive children with hand injuries requiring surgery, aged < 16 years, who visited the ED from January 2011 through September 2016. Information was obtained regarding age and gender of the children, seasonal and daily distribution of the visits, location, cause, site, and level of the injury, the diagnosis, and presence of serious injury. The children were classified into 3 age groups; toddlers (0 to 3 years), preschoolers (4 to 6 years), and schoolers (7 to 15 years). Severe injury was defined as amputation or crush injury. Results Mean age of the children was 7.4 ± 5.0 years and boys accounted for 65.7%. The most frequent visits occurred during the weekend (53.1%) and in spring (30.7%), and most children visited the ED with injuries that occurred at home and indoors (55.2% and 79.9%, respectively). The most common cause, site, and level of the injury were sharp object (34.8%), fingers other than the thumb and index finger (64.7%), and the distal phalanx (46.7%), respectively. In the toddler group, domestic, indoor, door-related, and distal phalanx injuries were more common than in the schooler group (P < 0.001). Physical contact or sharp object-related injuries increased with increasing age (P < 0.001). Severe injuries were more common among the toddlers than the schoolers (P < 0.001). Conclusion In the toddler group, domestic, indoor, door-related, distal phalanx, and severe injuries were more common than in the schooler group. These characteristics by age groups would aid in preventing hand injury in children, especially toddlers
Graphene quantum dots as anti-inflammatory therapy for colitis
While graphene and its derivatives have been suggested as a potential nanomedicine in several biomimetic models, their specific roles in immunological disorders still remain elusive. Graphene quantum dots (GQDs) may be suitable for treating intestinal bowel diseases (IBDs) because of their low toxicity in vivo and ease of clearance. Here, GQDs are intraperitoneally injected to dextran sulfate sodium (DSS)-induced chronic and acute colitis model, and its efficacy has been confirmed. In particular, GQDs effectively prevent tissue degeneration and ameliorate intestinal inflammation by inhibiting T(H)1/T(H)17 polarization. Moreover, GQDs switch the polarization of macrophages from classically activated M1 to M2 and enhance intestinal infiltration of regulatory T cells (T-regs). Therefore, GQDs effectively attenuate excessive inflammation by regulating immune cells, indicating that they can be used as promising alternative therapeutic agents for the treatment of autoimmune disorders, including IBDs.
Shining Light on the Shadow: Full-round Practical Distinguisher for Lightweight Block Cipher Shadow
Shadow is a lightweight block cipher proposed at IEEE IoT journal 2021. Shadow’s main design principle is adopting a variant 4- branch Feistel structure in order to provide a fast diffusion rate. We define such a structure as Shadow structure and prove that it is al- most identical to the Generalized Feistel Network, which invalidates the design principle. Moreover, we give a structural distinguisher that can distinguish Shadow structure from random permutation with only two plaintext/ciphertext pairs. By exploiting the key schedule, the distin- guisher can be extended to key recovery attack with only one plain- text/ciphertext pair. Furthermore, by considering Shadow’s round func- tion, only certain forms of monomials can appear in the ciphertext, re- sulting in an integral distinguisher of four plaintext/ciphertext pairs. Even more, the algebraic degree does not increase more than 12 for Shadow-32 and 20 for Shadow-64 regardless of rounds used. Our results show that Shadow is highly vulnerable to algebraic attacks, and that algebraic attacks should be carefully considered when designing ciphers with AND, rotation, and XOR operations
Nanogrooved microdiscs for bottom-up modulation of osteogenic differentiation
Grooved topographical features have effectively modulated cell differentiation on two-dimensional substrates. To transpose patterning into a 3D environmment, nanogrooved microdiscs, "topodiscs", are produced as cell carriers for bottom-up cell-mediated assembly. While enhancing cell proliferation, topodiscs led to the formation of bone-like aggregates, even in culture medium lacking osteoinductive factors.publishe
Development of procedural expertise to support multiattribute spatial decision-making
This study focuses on the development of process oriented support for planning support systems. To support exploration of ill-structured planning problems, planning support systems should be incorporated within planning processes, decision-oriented rather than just analysis-oriented, and able to provide effective procedural supports.To attain these claims about good planning support systems, a DSS Generator for multi-attribute judgment was developed. Complementary, synthetic use of four judgment methods--MAUT, AHP, CEA and ELECTRE--and heuristic rules was explored in constructing the judgment module. Procedural support strategies for ill-structured judgment methods were developed by Monte-Carlo simulation and implemented in the module. To demonstrate the effectiveness of this module, it was integrated into a DSS, PEGASUS, that also supports the design phase. A specific planning situation--a bus routing problem--was identified, and a module for alternative generation was constructed.Evaluation of the system showed that the system fulfilled what it was designed to do. Observations of use patterns of the system showed that access to multiple judgment methods and alternative generation methods allowed users to explore problems constructively and iteratively. The procedural supports were accepted by users on most occasions and allowed them to use the judgment methods spending less effort on procedural judgments. The system thus proved by example that some procedural expertise can be identified and that this expertise can be brought to bear in an operational system.A number of implications for future research were raised through this study. Suggested directions for future research include the application of PEGASUS to other planning domains, extension of procedural support for other phases of the decision making process, and exploration of more active use of value information in the design phase. Some perceptual observations--the different learning curves of the judgment methods and the complementary roles of multiple judgment methods--also deserve further exploration with an experimental design.U of I OnlyETDs are only available to UIUC Users without author permissio
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