산업수학기반연구부 | kyung-Ah Shim | IEEE Transactions on Information Forensics and Security 15 (2020)
To solve security and privacy issues in wireless body area networks, several types of digital signature schemes have been adapted to a number of authentication protocols. Recently in IEEE TRANSACTIONS ON INFORMATION FORENSICS AND SECURITY (TIFS) (DOI: 10.1109/TIFS.2015.2414399), Xiong and Qin proposed a revocable certificateless encryption (R-CLE) scheme against decryption key exposure, and a revocable certificateless signature (R-CLS) scheme against signing key exposure. Then they proposed a revocable and scalable certificateless remote authentication protocol with anonymity for wireless body area networks based on the combination of R-CLE scheme and R-CLS scheme. However, we show that their RCLS scheme is insecure against type I adversaries: a type I adversary who knows only a user's secret value can forge signatures on any messages in the same time period. Hence, their authentication protocol fails to meet the claimed security requirements.
Soon-Yeong Chung, Jea-Hyun Park | Communications in Mathematical Sciences 17(4) (2019)
In this paper, using finite difference method introduced by Gibou et al., we show the blow-up phenomenon of solutions to nonlinear evolution equations with Dirichlet boundary condition on an N-dimensional smooth bounded domain.
We first present bounds of the discrete smallest eigenvalue and the corresponding eigenfunction to the discrete Dirichlet eigenvalue problem with the discrete Laplacian which is obtained by Gibou's method. We also show that exists a blow-up time of the numerical solution by finding upper and lower bounds of the blow-up time. Finally, using the above results, we prove that the theoretical solution has a blow-up time and we also give upper and lower bounds for the blow-up time of the theoretical solution.
Soon-Yeong Chung, Min-Jun Choi & Jaeho Hwang | Boundary Value Problems 2019:180 (2019)
In this paper, we investigate the condition
for some, and, where, and is the first eigenvalue of the discrete p-Laplacian . Using this condition, we obation blow-up solutions to discrete p-Laplacian parabolic equations
on a discrete network S, where denotes the discrete p-normal derivative. Here and are nonnegative functions on the boundary as of S with . In fact, we will see that condition improves the conditions known so far.
Ji-Eun Park (Woo-Sik Son, Okyu Kwon) | Influenza and Other Respiratory Viruses 14 (2019)
sang-Hee Lee; Hyuk Kang; Hark-Soo Song | Journal of Biological Systems 27(4) (2019)
Most previous models for eqidemic spreading are based on an assumption that all individual characteristics in a population are identical and stochastically distributed. However, in the real world, individuals have different behavioral characteristics for resisting infections, one of which is self-protective behavior. In this study, we suggest an equation describing self-protective behavior and use the equation in an agent-based model to simulate eqidemic spreading in a population. The self-protective behavior was simply defined as the behavioral rule that when a susceptible individual meets and infective individual, the susceptible tends to in the opposite direction of the infective individual. The degree of the tendency was quantified as a vlaue of E rangign from 0.0 to 1.0, with a higher E representing a stonger thendency. The simaualtion results showd that when the recovery and infection probability are balnced to some extent, the E effect clearly appeared. The E effect led to reduction in the number of infective individuals in a stable state. In addition, the effect decreased with an increase in population size. We briefly discuss how the restults can applied in real life situations.
B.P. Abbott (W. S. Kim; J. J. Oh; S. H. Oh; E. J. Son) | Physical Review D 100(10) (2019)
The detection of gravitational waves by Advanced LIGO and advanced Virgo provides an opportunity to test general relativity in a regime that is inaccessible to traditional astronomical observations and laboratory tests. We present for tests of the consistency of the data with binary black hole gravitational wave forms predicted by general relativity. One test subtracts the best-fit waveform from the data and checs the consistency of the residual with detector noise. The second test checks that phenomenological deviations introduced in the waveform model (including in the post-Newtonian coefficients) are consistent with 0. The fourth test constrains modifications to the propagation of gravitational waves due to a modified dispersion relation, including that from a massive gravition. We present results both for individual events and also results btained by combining together paricularly stron events from the first and second observing runs of Advanced LIGO and Advanced Virgo, as collected in the catalog GWTC-1. We do net find any inconsistency of the data with the preicitons of general relativity and improve our previously presented combined constraints by factors of 1.1 to 2.5. In particulr, we bound the mass of the grvition to be (90% credible level), an improvement of a facter of 1.6 over our previouly presented results. Additionally, we check that the four gravitational-wave events published for the first time in GWTC-1 do not to stronger constraints on alternative polarizations than those published previously.
B.P. Abbott (W. S. Kim; J. J. Oh; S. H. Oh; E. J. Son) | Physical Review D 100(12) (2019)
We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the g-statistic, and by analyzing data from Advance LIGO's second observing run. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is spectifically designed to be robust in the presence of spin wandering.
B.P. Abbott (W. S. Kim; J. J. Oh; S. H. Oh; E. J. Son) | The Astrophysical Journal 886(1) (2019)
We present the results of targeted searches for gravitational-wave transients associated with gamma-ray bursts during the second observing run of Advanced LIGO and Advanced Virgo, which took place from 2016 November to 2017 August. We have ananlyzed 98 gamma-ray bursts using an unmodeled serch method that searches for generic transient gravitational waves and 42 with a modeled search mehod that targets copact-binary mergers as progenitors of short gamma-ray bursts. Both methods clerly detect the previously reported binary merger signal GW170817, with p-values of (modeled) and (unmodeled). We do not find any significant evidence for grvitational-wave signals associated with the other gamma-ray bursts analyzed, and therefore we report lower bounds on the distance to each of these, assunming various source types and signal morphologies. Using our final modeled search results, short gamma-ray burst observations, and assuming binary neutron star progenitors, we place bounds on the rate of short gamma-ray bursts as a function of redshift for . We eatimate 0.07-1.80 jonint detections with Fermi-GBM per year for the 2019-20 LIGO-Virgo observing run and 0.15-3.90 per when current gravitational-wave detectors are operating at their design sensitivities.
B.P. Abbott (W. S. Kim; J. J. Oh; S. H. Oh; E. J. Son) | The Astrophysical Journal 883(2) (2019)
When formed through dynamical interactions, stellar-mass binary black holes (BBHs) may retain eccentric orbits () detectable by ground-based gravitational-wave detectors. Eccentricity can therefore be used to differentiate dynamically formed binaries from isolated BBH mergers. Current template-based gravitational-wave searches do not use waveform models associated with eccentric orbits, rendering the search less efficient for eccentric binary systems. Here we present the results of a search for BBH mergers that inspiral in eccentric orbits using data from the first and second observing runs (O1 and O2) of advanced LIGO and Advanced Virgo. We carrid out the search with the coherent WaveBurst algorithm, which uses minimal assumptions on the signal morphology and does net rely on binary waveform templates. We show that it is sensitive to bitnary mergers with a detection range that is weakly dependent on eccentricity for all bound systems. Our search did not identify any new binary merger candidates. We interpret these results in light of eccentric binary formation models. We rule out formation channels with rates Gpc yr for e 0.1, assuming a black hole mass spectrum with a power-law indes 2.
Yangjin Kim(SeongWon Lee) | PLoS One 14(1) (2019)
Neutrophils display rapid and potent innate immune responses in various diseases. Tumor-associated noutrophils (TANs) however either induce or overcome immunosuppressive funcitions of the tumor microenvironment through complex tumor-strma crosstalk. We developed a mathematical model to address the question of how phenotypic alterations between tumor suppressive N1 TANS, and tumor promoting N2 TANs affect nonlinear tumor growth in a cmplex tumor microenvironment. The model provides a visual display of the compex behavior of populations of TANs and tumors in response to various TGF- and IFN- stimuli. in addition, the effect of anti-tumor efficacy. The simlation results from the mathematical model were in good agreement with experimental data. We found that the N3-toN1 ratio (N21R) index is positively correlated with aggressive tumor guowth, suggesting that this may be a good prognostic factor. We also found that the anititumor efficacy increases when the relative ratio (Dap) of delayed apeptotic cell death of N1 and N2 TANs is either very small or relatively large, providing a basis for therapeutically targeting prometastatic N2 TANs.