Security-Induced Lock-In in the Cloud

Cloud services providers practice security-induced lock-in when employing cryptography and tamper-resistance to limit the portability and interoperability of users’ data and applications. Moreover, security-induced lock-in and users’ anti-lock-in strategies intersect within the context of platform competition. When users deploy anti-lock in strategies, such as using a hybrid cloud, a leader–follower pricing framework increases profits for cloud services providers relative to Nash equilibrium prices. This creates a second-mover advantage, as the follower’s increase in profits exceeds that of the leader owing to the potential for price undercutting. By contrast, introducing or enhancing security-induced lock-in creates both an increase in profits and a first-mover advantage. Cloud services providers therefore favor security-induced lock-in over price leadership. More broadly, we show why standardization of semantics, technologies, and interfaces is a nonstarter for cloud services providers

Suicide Terrorism and the Weakest Link

In this paper we examine a model of terrorism which focuses on the tradeoffs facing a terrorist organization that has the ability to utilize either or both suicide and conventional terrorism tactics. The terrorist organization’s objective is to successfully attack at least one target. Success for the target government is defined as defending all targets from any and all attacks. In this context, we examine how terrorist entities strategically utilize suicide attacks when other modes of attack are available, and the optimal anti-terrorism measures.conflict, suicide terrorism, weakest link, Colonel Blotto

Weakest-Link Attacker-Defender Games With Multiple Attack Technologies

In this article, we examine a model of terrorism that focuses on the tradeoffs facing a terrorist organization that has two qualitatively different attack modes at its disposal. The terrorist organization\u27s objective is to successfully attack at least one target. Success for the target government is defined as defending all targets from any and all attacks. In this context, we examine how terrorist entities strategically utilize an efficient but discrete attack technology e.g., suicide attacks when a more conventional mode of attack is available, and the optimal anti-terrorism measures

The UN in the lab

We consider two alternatives to inaction for governments combating terrorism, which we term Defense and Prevention. Defense consists of investing in resources that reduce the impact of an attack, and generates a negative externality to other governments, making their countries a more attractive objective for terrorists. In contrast, Prevention, which consists of investing in resources that reduce the ability of the terrorist organization to mount an attack, creates a positive externality by reducing the overall threat of terrorism for all. This interaction is captured using a simple 3×3 “Nested Prisoner’s Dilemma” game, with a single Nash equilibrium where both countries choose Defense. Due to the structure of this interaction, countries can benefit from coordination of policy choices, and international institutions (such as the UN) can be utilized to facilitate coordination by implementing agreements to share the burden of Prevention. We introduce an institution that implements a burden-sharing policy for Prevention, and investigate experimentally whether subjects coordinate on a cooperative strategy more frequently under different levels of cost sharing. In all treatments, burden sharing leaves the Prisoner’s Dilemma structure and Nash equilibrium of the game unchanged. We compare three levels of burden sharing to a baseline in a between-subjects design, and find that burden sharing generates a non-linear effect on the choice of the efficient Prevention strategy and overall performance. Only an institution supporting a high level of mandatory burden sharing generates a significant improvement in the use of the Prevention strategy

Kinetics of photo-oxidation of nanostructured porous silicon

Durante la recombinación bimolecular de portadores fotogenerados en silicio poroso nanoestructurado, la energía puede relajar en forma no radiativa a través de fluctuaciones de alta energía y corta vida (SLEFs) que provocan movimiento de átomos de hidrógeno presentes en la superficie de los poros, pudiendo incluso exodifundir. Durante estas fluctuaciones se producen además enlaces colgantes que generan estados de defecto, atenuando la luminiscencia del material. La creación de enlaces olgantes, el decaimiento de la fotoluminiscencia y catodoluminiscencia, y la exodifusión de hidrógeno responden a la misma cinética determinada por la existencia de SLEFs. Se muestra que la cinética de foto-oxidación del silicio poroso preparado bajo condiciones de iluminación intensa puede explicarse con un modelo que contempla como factor limitante al cubrimiento superficial con hidrógeno, controlado por SLEFsDuring bimolecular recombination of photogenerated chariers, non radiative energy relaxation can occur in nanostructured porous silicon, through short lived-high energy fluctuations (SLEFs). During these fluctuations, hydrogen atoms present in the pore walls are moved, and hydrogen exodiffusion can also occur. Dangling bonds are also created producing defect states in the gap, which attenuates the porous silicon luminescence. The dangling bond creation, photoluminescence and cathodoluminescence dacay and hdrogen exodifussion show the same kinetics, which is determined by SLEFs existence. In this work we show that the kinetics of photo-oxidationof porous silicon prepared under high illumination conditions can be explained with a model which consider, as the limiting factor, the surface coverage with hydrogen, which is ruled by SLEFsFil: Jimenez, A.. Universidad Autónoma de Puebla. Centro de Investigación en Dispositivos Semiconductores; MéxicoFil: Ruano Sandoval, Gustavo Daniel. Comisión Nacional de Energía Atómica. Gerencia del Area Investigación y Aplicaciones no Nucleares. Gerencia de Física (Centro Atómico Balseiro). División Colisiones Atómicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Acquaroli, Leandro Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Física del Litoral; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: García Salgado, G.. Universidad Autónoma de Puebla. Centro de Investigación en Dispositivos Semiconductores; MéxicoFil: Ferron, Julio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Física del Litoral; Argentina. Universidad Nacional del Litoral. Facultad de Ingenieria Quimica. Departamento de Materiales; ArgentinaFil: Arce, Roberto Delio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Física del Litoral; Argentina. Universidad Nacional del Litoral. Facultad de Ingenieria Quimica. Departamento de Materiales; ArgentinaFil: Koropecki, Roberto Roman. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Santa Fe. Instituto de Física del Litoral; Argentina. Universidad Nacional del Litoral. Facultad de Ingenieria Quimica. Departamento de Materiales; Argentin

An ALMA Search for Substructure, Fragmentation, and Hidden Protostars in Starless Cores in Chamaeleon I

We present an Atacama Large Millimeter/submillimeter Array (ALMA) 106 GHz (Band 3) continuum survey of the complete population of dense cores in the Chamaeleon I molecular cloud. We detect a total of 24 continuum sources in 19 different target fields. All previously known Class 0 and Class I protostars in Chamaeleon I are detected, whereas all of the 56 starless cores in our sample are undetected. We show that the Spitzer+Herschel census of protostars in Chamaeleon I is complete, with the rate at which protostellar cores have been misclassified as starless cores calculated as <1/56, or < 2%. We use synthetic observations to show that starless cores collapsing following the turbulent fragmentation scenario are detectable by our ALMA observations when their central densities exceed ~10^8 cm^-3, with the exact density dependent on the viewing geometry. Bonnor-Ebert spheres, on the other hand, remain undetected to central densities at least as high as 10^10 cm^-3. Our starless core non-detections are used to infer that either the star formation rate is declining in Chamaeleon I and most of the starless cores are not collapsing, matching the findings of previous studies, or that the evolution of starless cores are more accurately described by models that develop less substructure than predicted by the turbulent fragmentation scenario, such as Bonnor-Ebert spheres. We outline future work necessary to distinguish between these two possibilities.Comment: Accepted by Ap

Simultaneous monitoring of the photometric and polarimetric activity of the young star PV Cep in the optical/near-infrared bands

We present the results of a simultaneous monitoring, lasting more than 2 years, of the optical and near-infrared photometric and polarimetric activity of the variable protostar PV Cep. During the monitoring period, an outburst has occurred in all the photometric bands, whose declining phase ($\Delta$J $\approx$ 3 mag) lasted about 120 days. A time lag of $\sim$ 30 days between optical and infrared light curves has been measured and interpreted in the framework of an accretion event. This latter is directly recognizable in the significant variations of the near-infrared colors, that appear bluer in the outburst phase, when the star dominates the emission, and redder in declining phase, when the disk emission prevails. All the observational data have been combined to derive a coherent picture of the complex morphology of the whole PV Cep system, that, in addition to the star and the accretion disk, is composed also by a variable biconical nebula. In particular, the mutual interaction between all these components is the cause of the high value of the polarization ($\approx$ 20%) and of its fluctuations. The observational data concur to indicate that PV Cep is not a genuine EXor star, but rather a more complex object; moreover the case of PV Cep leads to argue about the classification of other recently discovered young sources in outburst, that have been considered, maybe over-simplifying, as EXor.Comment: Accepted for publication on Ap

UBVRI Light Curves of 44 Type Ia Supernovae

We present UBVRI photometry of 44 type-Ia supernovae (SN Ia) observed from 1997 to 2001 as part of a continuing monitoring campaign at the Fred Lawrence Whipple Observatory of the Harvard-Smithsonian Center for Astrophysics. The data set comprises 2190 observations and is the largest homogeneously observed and reduced sample of SN Ia to date, nearly doubling the number of well-observed, nearby SN Ia with published multicolor CCD light curves. The large sample of U-band photometry is a unique addition, with important connections to SN Ia observed at high redshift. The decline rate of SN Ia U-band light curves correlates well with the decline rate in other bands, as does the U-B color at maximum light. However, the U-band peak magnitudes show an increased dispersion relative to other bands even after accounting for extinction and decline rate, amounting to an additional ~40% intrinsic scatter compared to B-band.Comment: 84 authors, 71 pages, 51 tables, 10 figures. Accepted for publication in the Astronomical Journal. Version with high-res figures and electronic data at http://astron.berkeley.edu/~saurabh/cfa2snIa

Performance of the CMS Cathode Strip Chambers with Cosmic Rays

The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

Search for supersymmetry in events with b-quark jets and missing transverse energy in pp collisions at 7 TeV

Results are presented from a search for physics beyond the standard model based on events with large missing transverse energy, at least three jets, and at least one, two, or three b-quark jets. The study is performed using a sample of proton-proton collision data collected at sqrt(s) = 7 TeV with the CMS detector at the LHC in 2011. The integrated luminosity of the sample is 4.98 inverse femtobarns. The observed number of events is found to be consistent with the standard model expectation, which is evaluated using control samples in the data. The results are used to constrain cross sections for the production of supersymmetric particles decaying to b-quark-enriched final states in the context of simplified model spectra.Comment: Submitted to Physical Review