Irregular and multi--channel sampling of operators

The classical sampling theorem for bandlimited functions has recently been generalized to apply to so-called bandlimited operators, that is, to operators with band-limited Kohn-Nirenberg symbols. Here, we discuss operator sampling versions of two of the most central extensions to the classical sampling theorem. In irregular operator sampling, the sampling set is not periodic with uniform distance. In multi-channel operator sampling, we obtain complete information on an operator by multiple operator sampling outputs

Size effect of Ruderman-Kittel-Kasuya-Yosida interaction mediated by electrons in nanoribbons

We calculated the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between the magnetic impurities mediated by electrons in nanoribbons. It was shown that the RKKY interaction is strongly dependent on the width of the nanoribbon and the transverse positions of the impurities. The transverse confinement of electrons is responsible for the above size effect of the RKKY interaction. It provides a potential way to control the RKKY interaction by changing nanostructure geometry

A Cloud Authentication Protocol using One-Time Pad

There is a significant increase in the amount of data breaches in corporate servers in the cloud environments. This includes username and password compromise in the cloud and account hijacking, thus leading to severe vulnerabilities of the cloud service provisioning. Traditional authentication schemes rely on the users to use their credentials to gain access to cloud service. However once the credential is compromised, the attacker will gain access to the cloud service easily. This paper proposes a novel scheme that does not require the user to present his credentials, and yet is able to prove ownership of access to the cloud service using a variant of zero-knowledge proof. A challenge-response protocol is devised to authenticate the user, requiring the user to compute a one-time pad (OTP) to authenticate himself to the server without revealing password to the server. A prototype has been implemented to facilitate the authentication of the user when accessing Dropbox, and the experiment results showed that the overhead incurred is insignificant

PEN+: An Emotional expression device and a mobile application for emotional health

Emotional health is an essential element in advancing towards one\u27s life goals and is inextricably connected with physical and social well-being. Since emotions involve physiological, behavioral, and cognitive changes, emotional problems can cause serious problems throughout one\u27s life. Understanding one\u27s emotional states precisely and suitably expressing emotions are the most salient methods for maintaining emotional health. However, managing and comprehending complicated changes in emotions can be personally challenging and demanding. This thesis not only concentrates on the process of design thinking to determine how to enhance personal emotional intelligence but also proposes the use of both a digital device for expressing emotions properly and a mobile application for having a better awareness of one\u27s emotional state. The intent of this study is to offer these new designs through an integrated process to improve emotional health in daily life

Channel-Width Dependent Enhancement in Nanoscale Field Effect Transistor

We report the observation of channel-width dependent enhancement in nanoscale field effect transistors containing lithographically-patterned silicon nanowires as the conduction channel. These devices behave as conventional metal-oxide-semiconductor field-effect transistors in reverse source drain bias. Reduction of nanowire width below 200 nm leads to dramatic change in the threshold voltage. Due to increased surface-to-volume ratio, these devices show higher transconductance per unit width at smaller width. Our devices with nanoscale channel width demonstrate extreme sensitivity to surface field profile, and therefore can be used as logic elements in computation and as ultrasensitive sensors of surface-charge in chemical and biological species.Comment: 5 pages, 4 figures, two-column format. Related papers can be found at http://nano.bu.ed

Period and toroidal knot mosaics

Knot mosaic theory was introduced by Lomonaco and Kauffman in the paper on `Quantum knots and mosaics' to give a precise and workable definition of quantum knots, intended to represent an actual physical quantum system. A knot (m,n)-mosaic is an $m \! \times \! n$ matrix whose entries are eleven mosaic tiles, representing a knot or a link by adjoining properly. In this paper we introduce two variants of knot mosaics: period knot mosaics and toroidal knot mosaics, which are common features in physics and mathematics. We present an algorithm producing the exact enumeration of period knot (m,n)-mosaics for any positive integers m and n, toroidal knot (m,n)-mosaics for co-prime integers m and n, and furthermore toroidal knot (p,p)-mosaics for a prime number p. We also analyze the asymptotics of the growth rates of their cardinality

Crafting Reputation before Domestic and International Audiences: Autocratic Participation in the United Nations Human Rights Institutions.

Why do some autocracies actively participate in international human rights institutions while their autocratic peers prefer to keep their engagement at a minimum? I argue that autocrats are motivated to participate by a desire to craft good reputations before domestic and international audiences. Hampered by commitment and information problems in their power-sharing relationship with ruling coalitions, autocrats with different support bases from their predecessors seek popular support to deter potential challenges from their new allies. Such autocrats find multiple ratifications of human rights agreements (HRAs) an expedient policy tool either to signal a break from their repressive autocratic predecessors or to reassure citizens by demonstrating continuity with their democratic predecessors in human rights protections. Among many other liberalization policies under autocrats, HRA memberships help governments appear to care for “broad interests” while still granting concentrated benefits to a small circle of regime insiders. Such autocrats make their promises more credible by accepting extra monitoring/enforcement procedures in addition to ratifying the main treaty, as long as the treaties concern general rights protections and allow them some control over those procedures. Likewise, autocracies actively engage in the Universal Periodic Review when seeking an enhanced reputation on human rights, either on their own or in relation to a particular state under review, in the eyes of the international audience. In particular, autocratic states with high profile positions in other international human rights institutions issue more meaningful recommendations to peer states. Autocracies also issue more serious recommendations to their foreign policy adversaries. Last, the meaningful recommendations issued by autocratic states mostly refer to international HRAs, but stop short of encouraging specific domestic reforms, as the recommending autocracy commits to a higher number of HRAs. I find strong supporting evidence in a series of empirical analyses based on a newly created dataset of individual autocrats’ records of ratification and acceptance of optional monitoring/enforcement of core UN HRAs from 1966 to 2008 and on a newly created directed dyadic dataset on UPR recommendations from 2008 to 2011. Qualitative data from elite interviews and site observation further corroborate the main findings.PhDPolitical ScienceUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/133208/1/mhhong_1.pd

Detection of the melanoma biomarker TROY using silicon nanowire field-effect transistors

Antibody-functionalized silicon nanowire field-effect transistors have been shown to exhibit excellent analyte detection sensitivity enabling sensing of analyte concentrations at levels not readily accessible by other methods. One example where accurate measurement of small concentrations is necessary is detection of serum biomarkers, such as the recently discovered tumor necrosis factor receptor superfamily member TROY (TNFRSF19), which may serve as a biomarker for melanoma. TROY is normally only present in brain but it is aberrantly expressed in primary and metastatic melanoma cells and shed into the surrounding environment. In this study, we show the detection of different concentrations of TROY in buffer solution using top-down fabricated silicon nanowires. We demonstrate the selectivity of our sensors by comparing the signal with that obtained from bovine serum albumin in buffer solution. Both the signal size and the reaction kinetics serve to distinguish the two signals. Using a fast-mixing two-compartment reaction model, we are able to extract the association and dissociation rate constants for the reaction of TROY with the antibody immobilized on the sensor surface

Sensing of the melanoma biomarker TROY using silicon nanowire field-effect transistors

Antibody-functionalized silicon nanowire field-effect transistors have been shown to exhibit excellent analyte detection sensitivity enabling sensing of analyte concentrations at levels not readily accessible by other methods. One example where accurate measurement of small concentrations is necessary is detection of serum biomarkers, such as the recently discovered tumor necrosis factor receptor superfamily member TROY (TNFRSF19), which may serve as a biomarker for melanoma. TROY is normally only present in brain but it is aberrantly expressed in primary and metastatic melanoma cells and shed into the surrounding environment. In this study, we show the detection of different concentrations of TROY in buffer solution using top-down fabricated silicon nanowires. We demonstrate the selectivity of our sensors by comparing the signal with that obtained from bovine serum albumin in buffer solution. Both the signal size and the reaction kinetics serve to distinguish the two signals. Using a fast-mixing two-compartment reaction model we are able to extract the association and dissociation rate constants for the reaction of TROY with the antibody immobilized on the sensor surface.The authors thank Biosite Diagnostics (San Diego, CA) for providing TROY antibodies. The authors acknowledge NIH, NSF, and Battelle Memorial Institute for support of this work. (NIH; NSF; Battelle Memorial Institute)https://pubs.acs.org/doi/pdf/10.1021/acssensors.6b00017Accepted manuscrip