Delayed Product Introduction

We investigate the incentives of a monopolistic seller to delay the introduction of a new and improved version of his product. By analyzing a three-period model, we show that the seller may prefer to delay introducing a new product, even though the enabling technologies for the product are already available. The underlying motivation is analogous to that found in the durable goods monopolist literature – the seller suffers from a time inconsistency problem that causes his old and new products to cannibalize each other. Without the ability to remove existing stock of the old product from the market, shorten product durability, or pace research and development (R&D), he may respond by selling the new product later. We characterize the equilibria with delayed introduction, and study their changes with respect to market and product parameters. In particular, we show that delayed introduction could occur regardless of whether the seller can offer upgrade discounts to consumers, that instead, it is related to quality improvement brought about by the new product, durabilities, and discount factors. Further, we show that delayed introduction could bring socially efficient outcomes as well. Based on the insights of the model, we provide practical suggestions on pricing and policies

Cyberattacks: Does Physical Boundry Matter?

Information security issues are characterized with interdependence. Particularly, cyber criminals can easily cross national boundaries and exploit jurisdictional limitations between countries. Thus, whether cyber attacks are spatially autocorrelated is a strategic issue for government authorities and a tactic issue for insurance companies. Through an empirical study of cyber attacks across 62 countries during the period 2003-2007, we find little evidence on the spatial autocorrelation of cyber attacks at any week. However, after considering economic opportunity, IT infrastructure, international collaboration in enforcement and conventional crimes, we find strong evidence that cyber attacks were indeed spatially autocorrelated as they moved over time. The policy and managerial implication is that physical boundary should be an important factor in addressing strategic cyber attacks and their potential risks

Periodic Radio Variability in NRAO 530: Phase Dispersion Minimization Analysis

In this paper, a periodicity analysis of the radio light curves of the blazar NRAO 530 at 14.5, 8.0, and 4.8 GHz is presented employing an improved Phase Dispersion Minimization (PDM) technique. The result, which shows two persistent periodic components of $\sim 6$ and $\sim 10$ years at all three frequencies, is consistent with the results obtained with the Lomb-Scargle periodogram and weighted wavelet Z-transform algorithms. The reliability of the derived periodicities is confirmed by the Monte Carlo numerical simulations which show a high statistical confidence. (Quasi-)Periodic fluctuations of the radio luminosity of NRAO 530 might be associated with the oscillations of the accretion disk triggered by hydrodynamic instabilities of the accreted flow. \keywords{methods: statistical -- galaxies: active -- galaxies: quasar: individual: NRAO 530}Comment: 8 pages, 5 figures, accepted by RA

2-(4-Bromo­phen­yl)quinoxaline

In the title compound, C14H9BrN2, the benzene and quinoxaline rings are almost coplanar [r.m.s. deviation = 0.0285 (3) Å and dihedral angle = 2.1 (2)°]

5,5′,5′′-Triphenyl-2,2′,2′′-[2,4,6-tri­methyl­benzene-1,3,5-triyltris(methyl­idene­sulfanedi­yl)]tris­(1,3,4-oxadiazole)

In the title compound, C36H30N6O3S3, the phenyl rings are twisted from the attached oxadiazole rings in the three arms by 1.5(2), 2.4 (2) and 25.7 (2)°. The crystal packing exhibits weak inter­molecular C—H⋯N inter­actions

5,5′-Diphenyl-2,2′-[butane-1,4-diylbis(sulfanedi­yl)]bis­(1,3,4-oxadiazole)

The complete mol­ecule of the title compound, C20H18N4O2S2, is generated by crystallographic inversion symmetry. The benzene ring is almost coplanar with the oxadiazole ring [dihedral angle = 7.2 (2)°]

Non-Abelian vortices in the emergent U(2) gauge theory of the Hubbard model

By the spin-fermion formula, the Hubbard model on the honeycomb lattice is represented by a U(2) gauge theory in the mean field method, non-Abelian vortex solutions are constructed based on this theory. The quantization condition shows that the magnetic flux quanta are half-integer. There are $2k$ bosonic zero modes for $k$ winding vortices. For the fermions, there are 2 zero energy states (ZESs) corresponding to the single elementary vortex. In the vortex core and on the edge, the system are in the semi-metal phase with a spin gap and in the insulator phase with N\'eel order phase, and can be mapped to the superconductor in class A and CI, respectively.Comment: 4pages, 2table

Driving cybersecurity policy insights from information on the Internet

National Research Foundation (NRF) Singapor