Newspapers and the Internet: friends or foes? : evidence of concentration of choice in Korea

Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 27).Does the expansion of the Internet provide opportunities for newspapers to attract more readers, or does it threaten their sustainability by cannibalizing subscription revenue from print circulation? To examine these competing hypotheses, I analyzed a unique data set of the monthly number of clicks on the homepages of the Web sites of four economic newspapers in Korea between 2001 and 2009. Using a unique quasi-experimental observation of the Korean media industry, I illustrated the differential impact of the Internet on leading newspapers and their followers. By attracting people to a common "playground" and providing inference information-namely information on others' decisions-the Internet has a significant impact on consumer choice of information products, reinforcing informational cascades through the inference effect. My findings reveal that since the advent of the Internet, customer preference has consistently been dominated by market leaders, strengthening the brand image of the leaders. This phenomenon will, over time, widen the gap between leading newspaper groups and laggards, providing new opportunities for market leaders only. Thus, my findings point to significant marketing strategies based on consumer choice.by Jun Mo Park.M.B.A

Development Of Water Meter For Secure Communication In The Advanced Metering Infrastructure

The Advanced Metering Infrastructure (AMI) is one of the integral components of the smart water grid where water consumption data is collected, stored, and transferred to the utility Meter Data Management System (MDMS). The organizations which are directly involved in promoting and developing the Smart Water Grid have tried to figure out the operating scenarios in the overall domain from the smart meters up to MDMS, and logical/physical components that should be expected to exist to perform those operations in the full extent. One of the daunting tasks in realizing the services in the AMI is the security issue. Unlike the utility operation system which is almost isolated from the outside world from the communication point of view, the AMI will lie in the open domain. Since water metering devices are located in an open network domain, any cyber attack that is excruciating the services of the Internet could take a toll on the services in the Smart Water Grid at the same level. In order to understand cyber security threats and define security requirements we explain the logical model of the AMI, and then based on the logical model we analyze the information flows to provide the advanced services in this domain. Based on the characteristics of devices that consist of the customer domain and the information flows for providing advanced services, we analyze the possible security attacks which exploit the vulnerability of devices and information flows. Next we address the implementation issue of the water meter. We propose possible approaches for developing the smart water meter in which the security functions should be integrated into metering and communication functions in the same box in economic and efficient ways

Health Behaviors and Academic Performance Among Korean Adolescents

SummaryPurposeThis study aimed to examine the most prominent health-related behaviors impacting the academic performance of Korean adolescents.MethodsThe 2012 Korea Youth Risk Behavior Web-Based Survey data were analyzed using an ordinal regression analysis after adjusting for general and other health behaviors.ResultsBefore adjustment, all health behaviors were significantly associated with academic performance. After adjustment for other health behaviors and confounding factors, only smoking [odds ratio (OR) = 2.07, 95% confidence interval (CI) (1.98, 2.16), p < .001], alcohol consumption [OR = 1.22, 95% CI (1.18, 1.27), p < .001], and physical activity [OR = 1.09, 95% CI (1.06, 1.13), p < .001] were associated with lower academic performance, and engaging in a regular diet [OR = 0.65, 95% CI (0.65, 0.62), p < .001] was associated with higher academic performance.ConclusionsRegular diet, reducing smoking and alcohol drinking, and physical activity should be the target when designing health interventions for improving academic performance in Korean adolescents

Gaussian time-dependent variational principle for the finite-temperature anharmonic lattice dynamics

The anharmonic lattice is a representative example of an interacting bosonic many-body system. The self-consistent harmonic approximation has proven versatile for the study of the equilibrium properties of anharmonic lattices. However, the study of dynamical properties therewithin resorts to an ansatz, whose validity has not yet been theoretically proven. Here, we apply the time-dependent variational principle, a recently emerging useful tool for studying the dynamic properties of interacting many-body systems, to the anharmonic lattice Hamiltonian at finite temperature using the Gaussian states as the variational manifold. We derive an analytic formula for the position-position correlation function and the phonon self-energy, proving the dynamical ansatz of the self-consistent harmonic approximation. We establish a fruitful connection between time-dependent variational principle and the anharmonic lattice Hamiltonian, providing insights in both fields. Our work expands the range of applicability of time-dependent variational principle to first-principles lattice Hamiltonians and lays the groundwork for the study of dynamical properties of the anharmonic lattice using a fully variational framework.Comment: v2: Added a citation to L. Monacelli and F. Mauri, "Time-Dependent Self Consistent Harmonic Approximation: Anharmonic nuclear quantum dynamics and time correlation functions," arXiv:2011.14986 and a note on i

Bisphosphonate inhibits the expression of cyclin A2 at the transcriptional level in normal human oral keratinocytes.

Nitrogen-containing bisphosphonates (N-BPs) are the most widely used anti-resorptive agents in the treatment of bone-related diseases. N-BPs inhibit bone resorption by specifically targeting osteoclasts, bone-resorbing cells. However, soft tissue toxicity, such as oral or gastrointestinal (GI) ulcerations has frequently been reported in N-BP users, suggesting that N-BPs may also directly target cells other than osteoclasts. Previously, we reported that BPs inhibit proliferation without inducing the apoptosis of normal human oral keratinocytes (NHOKs). However, the molecular mechanisms through which N-BPs inhibit the proliferation of NHOKs are not yet fully understood. In this study, we performed gene expression profiling in N-BP-treated NHOKs and identified cyclin A2 as one of the most commonly downregulated genes. When the NHOKs were treated with N-BPs, we found that the level of cyclin A2 was suppressed in a dose- and time-dependent manner. In addition, the protein level of cyclin A2 was also significantly lower in oral epithelial cells in N-BP-treated oral mucosal tissue constructs. Cyclin A2 promoter reporter assay revealed that N-BPs inhibited the luciferase activity, indicating that the inhibition of cyclin A2 expression occurs at the transcriptional level. Furthermore, N-BPs did not alter the expression of cyclin A2 in normal human oral fibroblasts (NHOFs), suggesting that the effect of N-BPs on cyclin A2 expression may be cell-type specific. Thus, the findings of our study demonstrate that the inhibition of NHOK proliferation by N-BPs is mediated, at least in part, by the suppression of cyclin A2 expression at the transcriptional level, which may explain the underlying mechanisms of soft tissue toxicity by N-BPs

Factorization of the 3d superconformal index

We prove that 3d superconformal index for general =2 U(N) gauge group with fundamentals and anti-fundmentals with/without Chern-Simons terms is factorized into vortex and anti-vortex partition function. We show that for simple cases, 3d vortex partition function coincides with a suitable topological open string partition function. We provide much more elegant derivation at the index level for =2 Seiberg-like dualities of unitary gauge groups with fundamantal matters and =4 mirror symmetry1114sciescopu

Cosmic Mach Number as a Function of Overdensity and Galaxy Age

We carry out an extensive study of the cosmic Mach number (\mach) on scales of R=5, 10 and 20h^-1Mpc using an LCDM hydrodynamical simulation. We particularly put emphasis on the environmental dependence of \mach on overdensity, galaxy mass, and galaxy age. We start by discussing the difference in the resulting \mach according to different definitions of \mach and different methods of calculation. The simulated Mach numbers are slightly lower than the linear theory predictions even when a non-linear power spectrum was used in the calculation, reflecting the non-linear evolution in the simulation. We find that the observed \mach is higher than the simulated mean by more than 2-standard deviations, which suggests either that the Local Group is in a relatively low-density region or that the true value of \Omega_m is ~ 0.2, significantly lower than the simulated value of 0.37. We show from our simulation that the Mach number is a weakly decreasing function of overdensity. We also investigate the correlations between galaxy age, overdensity and \mach for two different samples of galaxies --- DWARFs and GIANTs. Older systems cluster in higher density regions with lower \mach, while younger ones tend to reside in lower density regions with larger \mach, as expected from the hierarchical structure formation scenario. However, for DWARFs, the correlation is weakened by the fact that some of the oldest DWARFs are left over in low-density regions during the structure formation history. For giant systems, one expects blue-selected samples to have higher \mach than red-selected ones. We briefly comment on the effect of the warm dark matter on the expected Mach number.Comment: 43 pages, including 15 figures. Accepted version in ApJ. Included correlation function of different samples of galaxies, and the cumulative number fraction distribution as a fcn. of overdensity. Reorganized figures and added some reference