93 research outputs found
Building On and Honoring Forty Years of PBL Scholarship from Howard Barrows: A Scientometric, Large-Scale Data, and Visualization-based Analysis
Get PDFOver the past forty years, Howard Barrows’ contributions to PBL research have influenced and guided educational research and practice in a diversity of domains. It is necessary to make visible to all PBL scholars what has been accomplished, what is perceived as significant, and what is the scope of applicability for Barrows’ groundbreaking findings. As more disciplines recognize Barrows’ efforts and adopt PBL in education, it becomes crucial but challenging to sustain community memory so that PBL scholars are kept well informed of research innovations in various domains. In this paper, we review Barrows’ scholarly efforts in PBL and reveal the impacts on subsequent studies in various domains. A bibliometrics analysis is conducted on Barrows’ PBL publications and the corresponding citations to quantitatively measure Barrows’ impact. Our findings demonstrate Barrows’ exceptional contributions to PBL and the disciplinary differences in conducting PBL studies based on Barrows’ work. It is also revealed that PBL scholars who share similar interests have rarely collaborated with each other. The PBL research community has a real opportunity to connect isolated research groups and reduce the fragmentation so that research innovations in one domain can be disseminated to inform other scholars
Quality Evaluation of Ginger from North East India and its Value Addition
No full textThis Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page
Discovering mentorship information from author collaboration networks
No full textResearchers are assessed from a researcher-centric perspective - by quantifying a researcher's contribution to the field. Citation and publication counts are some typical examples. We propose a student-centric measure to assess researchers on their mentoring abilities. Our approach quantifies benefits bestowed by researchers upon their students by characterizing the publication dynamics of research advisor-student interactions in author collaboration networks. We show that our measures could help aspiring students identify research advisors with proven mentoring skills. Our measures also help in stratification of researchers with similar ranks based on typical indices like publication and citation counts while being independent of their direct influences
Isomorphic immigrant effect in foreign entry
Get PDFThe key problem for commitment to international business activities
is the limited knowledge of a host country. A firm’s host country experience
and its history of entry patterns in other countries shapes entry preferences into
a foreign country (Pan and Tse, 2000; Chung and Enderwick, 2001; Yiu and
Makino, 2002; Li and Meyer, 2008). In the past decade, scholars became aware
of the effect of a specific kind of international experience within the firm: the
immigrant effect (Chung and Enderwick, 2001; Tadesse and White, 2008;
White and Tadesse, 2008; Madhavan and Iriyama, 2009). The present paper
reports on the role immigrants fulfil in foreign entry plans and how their
involvement relates to the outcome of the foreign entry go/no-go decision.
Findings confirm that among the firms that continue in entry, the presence of
immigrants in the firm is relatively high. But, and this is unexpected, the same
is true for firms that cancel entry plans (Oortwijn, 2010a)
How interrelated are MIST equity markets with the developed stock markets of the world?
No full textThis study explores the long-run and short-term relationship between the Mexico, Indonesia, South Korea, and Turkey (MIST) equity markets and the developed stock markets such as US, UK, Germany, Japan, Hong Kong, and Singapore. To start with, the author employs static bivariate and multivariate Johansen cointegration tests to test for long-run relationship between each of MIST equity markets and the developed stock markets. Subsequently, the author employs the recursive multivariate Johansen cointegration tests to garner a better understanding of the evolution of extent of integration between MIST and the developed stock markets. Static and Recursive Johansen Test findings reveal lack of consistent cointegrating relationship between MIST and developed markets (DM). Consequently, MIST equity markets do offer portfolio diversification avenues for international investors. On the short-term front, the time-varying correlations for each MIST-DM pair of stock indices were examined using the Dynamic Conditional Correlation (DCC) specification of the Multivariate GARCH. Of all the developed stock markets considered for this study, Mexico is found to exhibit high DCC with US and least amount of DCC with Japan while Indonesia is found to exhibit high DCC with Singapore and Hong Kong and least amount of DCC with US. Lastly, when it comes to South Korea, it exhibits the least amount of DCC with US and high DCC with Hong Kong, Singapore, and Japan
Characterizing low-frequency flame-front oscillations – An investigation into their origin and possible mitigation
No full textThis investigation focuses on the premixed conical flame, a mainstay of combustion diagnostics. While extensive studies have explored high-frequency oscillations in the canonical Bunsen flame, little attention has been given to low-frequency oscillations affecting flame fronts. This thesis aims to explain the origins of these oscillations and proposes mitigation strategies. The goal is to improve high-accuracy diagnostics of standard conical flames by generating stable flame plumes through oscillation reduction.The thesis explores two theories for low-frequency oscillations: buoyancy variations and flow rate fluctuations. Image chemiluminescence and CARS spectroscopy validate these hypotheses. Spatial oscillations are detected using flame front edge detection algorithms, while CARS analysis indirectly confirms fluctuations. Preliminary experiments establish reference data sets, followed by a primary experimental campaign spanning Reynolds numbers from 500 to 1000 for constant equivalence ratios. This isolates the effect of buoyancy variations. The report concludes by suggesting simple design changes for the flame holder to reduce instability amplitudes.Aerospace Engineerin
On the Security of Non-Linear HB (NLHB) Protocol Against Passive Attack
Get PDFAs a variant of the HB authentication protocol for RFID systems, which relies on the complexity of decoding linear codes against passive attacks, Madhavan et al. presented Non-Linear HB(NLHB) protocol. In contrast to HB, NLHB relies on the complexity of decoding a class of non-linear codes to render the passive attacks proposed against HB ineffective. Based on the fact that there has been no passive solution for the problem of decoding a random non-linear code, the authors have claimed that NLHB’s security margin is very close to its key size. In this paper, we show that passive attacks against HB protocol can still be applicable to NLHB and this protocol does not provide the desired security margin. In our attack, we first linearize the non-linear part of NLHB to obtain a HB equivalent for NLHB, and then exploit the passive attack techniques proposed for the HB to evaluate the security margin of NLHB. The results show that although NLHB’s security margin is relatively higher than HB against similar passive attack techniques, it has been overestimated and, in contrary to what is claimed, NLHB is vulnerable to passive attacks against HB, especially when the noise vector in the protocol has a low weight
Cluster Identification : Topic Models, Matrix Factorization And Concept Association Networks
Get PDFThe problem of identifying clusters arising in the context of topic models and related approaches is important in the area of machine learning. The problem concerning traversals on Concept Association Networks is of great interest in the area of cognitive modelling. Cluster identification is the problem of finding the right number of clusters in a given set of points(or a dataset) in different settings including topic models and matrix factorization algorithms. Traversals in Concept Association Networks provide useful insights into cognitive modelling and performance. First, We consider the problem of authorship attribution of stylometry and the problem of cluster identification for topic models. For the problem of authorship attribution we show empirically that by using stop-words as stylistic features of an author, vectors obtained from the Latent Dirichlet Allocation (LDA) , outperforms other classifiers. Topics obtained by this method are generally abstract and it may not be possible to identify the cohesiveness of words falling in the same topic by mere manual inspection. Hence it is difficult to determine if the chosen number of topics is optimal. We next address this issue. We propose a new measure for topics arising out of LDA based on the divergence between the singular value distribution and the L1 norm distribution of the document-topic and topic-word matrices, respectively. It is shown that under certain assumptions, this measure can be used to find the right number of topics. Next we consider the Non-negative Matrix Factorization(NMF) approach for clustering documents. We propose entropy based regularization for a variant of the NMF with row-stochastic constraints on the component matrices. It is shown that when topic-splitting occurs, (i.e when an extra topic is required) an existing topic vector splits into two and the divergence term in the cost function decreases whereas the entropy term increases leading to a regularization.
Next we consider the problem of clustering in Concept Association Networks(CAN). The CAN are generic graph models of relationships between abstract concepts. We propose a simple clustering algorithm which takes into account the complex network properties of CAN. The performance of the algorithm is compared with that of the graph-cut based spectral clustering algorithm. In addition, we study the properties of traversals by human participants on CAN. We obtain experimental results contrasting these traversals with those obtained from (i) random walk simulations and (ii) shortest path algorithms
Scanning tunneling microscopy studies of a tunable topological insulator and magnetic Weyl semimetal
Get PDFThe discovery of topological order with material systems, and the unique electronic states necessitated by non-trivial topology, has been a major thrust of condensed matter research for the past two decades. As exotic topological electronic states often manifest themselves at reduced dimensional interfaces, local experimental probes play an important role in the understanding and development of topological materials. In this thesis, I describe the construction of a Scanning Tunneling Microscope (STM) for the study of topological materials. After construction, the tunable topological insulator system Ge(Bix,Sb1-x)2Te4 and the magnetic Weyl semimetal Co3Sn2S2 were studied. In Ge(Bix,Sb1-x)2Te4, increasing Sb substitution effectively electron dopes the sample and moves the Dirac point from 300 meV below the Fermi energy to energies above the Fermi energy while remaining topological. As the topological surface states in this material are well isolated from the bulk bands, Dirac point tuning in this material system has interesting consequences for potential spintronic applications, as well as existing thermoelectric and phase change applications. In Co3Sn2S2, the seminal model of a magnetic Weyl semimetal as a stacking of Chern insulators is extended to step edges exposed upon cleavage. We find that for a large region of parameter space within this model, the chiral edge states present in the 2D limit can be recovered on surfaces where the inter-layer coupling is sufficiently reduced. Our subsequent STM study finds an edge state on the kagome Co3Sn surface, which is predicted to be a Chern insulator in the 2D limit. STM density of states maps on thin terraces of the Co3Sn surface show quantum well like bound states that have a linear dependence on the nth bound state and energy. By constructing a tight binding model of linearly dispersing states that can hybridize, we reproduce our results on the terrace. These results suggest that elusive chiral edge states could be studied by local probe measurements within bulk materials. Additionally, our experiments provide evidence that Co3Sn2S2 could host the quantum anomalous Hall effect at elevated temperatures in the 2D limit.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2022-05-01The student, Sean Howard, accepted the attached license on 2020-04-22 at 10:07.The student, Sean Howard, submitted this Dissertation for approval on 2020-04-22 at 10:16.This Dissertation was approved for publication on 2020-04-22 at 15:59.DSpace SAF Submission Ingestion Package generated from Vireo submission #15032 on 2020-08-25 at 17:27:57Made available in DSpace on 2020-08-26T23:54:36Z (GMT). No. of bitstreams: 2
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Previous issue date: 2020-04-22Embargo set by: Seth Robbins for item 115729
Lift date: 2022-08-26T23:54:40Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 115729
Lift date: 2022-08-26T23:55:59Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 115729
Lift date: 2022-08-26T23:57:28Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 115729
Lift date: 2022-08-26T23:58:55Z
Reason: Author requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemAuthor requested U of Illinois access only (OA after 2yrs) in Vireo ETD systemU of I Onl
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