Mechanistic modeling of architectural vulnerability factor

Reliability to soft errors is a significant design challenge in modern microprocessors owing to an exponential increase in the number of transistors on chip and the reduction in operating voltages with each process generation. Architectural Vulnerability Factor (AVF) modeling using microarchitectural simulators enables architects to make informed performance, power, and reliability tradeoffs. However, such simulators are time-consuming and do not reveal the microarchitectural mechanisms that influence AVF. In this article, we present an accurate first-order mechanistic analytical model to compute AVF, developed using the first principles of an out-of-order superscalar execution. This model provides insight into the fundamental interactions between the workload and microarchitecture that together influence AVF. We use the model to perform design space exploration, parametric sweeps, and workload characterization for AVF

Optimizing soft error reliability through scheduling on heterogeneous multicore processors

Reliability to soft errors is an increasingly important issue as technology continues to shrink. In this paper, we show that applications exhibit different reliability characteristics on big, high-performance cores versus small, power-efficient cores, and that there is significant opportunity to improve system reliability through reliability-aware scheduling on heterogeneous multicore processors. We monitor the reliability characteristics of all running applications, and dynamically schedule applications to the different core types in a heterogeneous multicore to maximize system reliability. Reliability-aware scheduling improves reliability by 25.4 percent on average (and up to 60.2 percent) compared to performance-optimized scheduling on a heterogeneous multicore processor with two big cores and two small cores, while degrading performance by 6.3 percent only. We also introduce a novel system-level reliability metric for multiprogram workloads on (heterogeneous) multicores. We provide a trade-off analysis among reliability-, power- and performance-optimized scheduling, and evaluate reliability-aware scheduling under performance constraints and for unprotected L1 caches. In addition, we also extend our scheduling mechanisms to multithreaded programs. The hardware cost in support of our reliability-aware scheduler is limited to 296 bytes per core

Oncogenic senescence: a multi-functional perspective.

Cellular senescence is defined as an irreversible growth arrest with the acquisition of a distinctive secretome. The growth arrest is a potent anticancer mechanism whereas the secretome facilitates wound healing, tissue repair, and development. The senescence response has also become increasingly recognized as an important contributor to aging and age-related diseases, including cancer. Although oncogenic mutations are capable of inducing a beneficial senescence response that prevents the growth of premalignant cells and promotes cancer immune-surveillance, the secretome of senescent cells also includes factors with pro-tumorigenic properties. On June 23rd and 24th, 2016, the Division of Cancer Biology of the National Cancer Institute sponsored a workshop to discuss the complex role of cellular senescence in tumorigenesis with the goal to define the major challenges and opportunities within this important field of cancer research. Additionally, it was noted how the development of novel tools and technologies are required to accelerate research into a mechanistic understanding of senescent cells in carcinogenesis in order to overcome the current limitations in this exciting, yet ill-defined area

Impact of Seismic Risk on Lifetime Property Values

This report presents a methodology for establishing the uncertain net asset value, NAV, of a real-estate investment opportunity considering both market risk and seismic risk for the property. It also presents a decision-making procedure to assist in making real-estate investment choices under conditions of uncertainty and risk-aversion. It is shown that that market risk, as measured by the coefficient of variation of NAV, is at least 0.2 and may exceed 1.0. In a situation of such high uncertainty, where potential gains and losses are large relative to a decision-maker's risk tolerance, it is appropriate to adopt a decision-analysis approach to real-estate investment decision-making. A simple equation for doing so is presented. The decision-analysis approach uses the certainty equivalent, CE, as opposed to NAV as the basis for investment decision-making. That is, when faced with multiple investment alternatives, one should choose the alternative that maximizes CE. It is shown that CE is less than the expected value of NAV by an amount proportional to the variance of NAV and the inverse of the decision-maker's risk tolerance, [rho]. The procedure for establishing NAV and CE is illustrated in parallel demonstrations by CUREE and Kajima research teams. The CUREE demonstration is performed using a real 1960s-era hotel building in Van Nuys, California. The building, a 7-story non-ductile reinforced-concrete moment-frame building, is analyzed using the assembly-based vulnerability (ABV) method, developed in Phase III of the CUREE-Kajima Joint Research Program. The building is analyzed three ways: in its condition prior to the 1994 Northridge Earthquake, with a hypothetical shearwall upgrade, and with earthquake insurance. This is the first application of ABV to a real building, and the first time ABV has incorporated stochastic structural analyses that consider uncertainties in the mass, damping, and force-deformation behavior of the structure, along with uncertainties in ground motion, component damageability, and repair costs. New fragility functions are developed for the reinforced concrete flexural members using published laboratory test data, and new unit repair costs for these components are developed by a professional construction cost estimator. Four investment alternatives are considered: do not buy; buy; buy and retrofit; and buy and insure. It is found that the best alternative for most reasonable values of discount rate, risk tolerance, and market risk is to buy and leave the building as-is. However, risk tolerance and market risk (variability of income) both materially affect the decision. That is, for certain ranges of each parameter, the best investment alternative changes. This indicates that expected-value decision-making is inappropriate for some decision-makers and investment opportunities. It is also found that the majority of the economic seismic risk results from shaking of S[subscript a] < 0.3g, i.e., shaking with return periods on the order of 50 to 100 yr that cause primarily architectural damage, rather than from the strong, rare events of which common probable maximum loss (PML) measurements are indicative. The Kajima demonstration is performed using three Tokyo buildings. A nine-story, steel-reinforced-concrete building built in 1961 is analyzed as two designs: as-is, and with a steel-braced-frame structural upgrade. The third building is 29-story, 1999 steel-frame structure. The three buildings are intended to meet collapse-prevention, life-safety, and operational performance levels, respectively, in shaking with 10%exceedance probability in 50 years. The buildings are assessed using levels 2 and 3 of Kajima's three-level analysis methodology. These are semi-assembly based approaches, which subdivide a building into categories of components, estimate the loss of these component categories for given ground motions, and combine the losses for the entire building. The two methods are used to estimate annualized losses and to create curves that relate loss to exceedance probability. The results are incorporated in the input to a sophisticated program developed by the Kajima Corporation, called Kajima D, which forecasts cash flows for office, retail, and residential projects for purposes of property screening, due diligence, negotiation, financial structuring, and strategic planning. The result is an estimate of NAV for each building. A parametric study of CE for each building is presented, along with a simplified model for calculating CE as a function of mean NAV and coefficient of variation of NAV. The equation agrees with that developed in parallel by the CUREE team. Both the CUREE and Kajima teams collaborated with a number of real-estate investors to understand their seismic risk-management practices, and to formulate and to assess the viability of the proposed decision-making methodologies. Investors were interviewed to elicit their risk-tolerance, r, using scripts developed and presented here in English and Japanese. Results of 10 such interviews are presented, which show that a strong relationship exists between a decision-maker's annual revenue, R, and his or her risk tolerance, [rho is approximately equal to] 0.0075R[superscript 1.34]. The interviews show that earthquake risk is a marginal consideration in current investment practice. Probable maximum loss (PML) is the only earthquake risk parameter these investors consider, and they typically do not use seismic risk at all in their financial analysis of an investment opportunity. For competitive reasons, a public investor interviewed here would not wish to account for seismic risk in his financial analysis unless rating agencies required him to do so or such consideration otherwise became standard practice. However, in cases where seismic risk is high enough to significantly reduce return, a private investor expressed the desire to account for seismic risk via expected annualized loss (EAL) if it were inexpensive to do so, i.e., if the cost of calculating the EAL were not substantially greater than that of PML alone. The study results point to a number of interesting opportunities for future research, namely: improve the market-risk stochastic model, including comparison of actual long-term income with initial income projections; improve the risk-attitude interview; account for uncertainties in repair method and in the relationship between repair cost and loss; relate the damage state of structural elements with points on the force-deformation relationship; examine simpler dynamic analysis as a means to estimate vulnerability; examine the relationship between simplified engineering demand parameters and performance; enhance category-based vulnerability functions by compiling a library of building-specific ones; and work with lenders and real-estate industry analysts to determine the conditions under which seismic risk should be reflected in investors' financial analyses

Political ecology of adaptation: claiming a critical biomimicry for the Anthropocene

En este artículo los autores se apropian del concepto de adaptación en el marco de la ecología política, con el propósito de repensar críticamente el principio de biomímesis como una estrategia capaz de contribuir a la construcción de una sociedad sustentable, en una época plagada de efectos adversos generados por el sistema socioeconómico. Se utiliza el concepto de «sostenibilidad» como una práctica emancipatoria, no solo en lo que atañe a problemas medioambientales sino, principalmente, a asuntos políticos. Una ecología política de la adaptación debería permitir, entonces, comprender la adaptación en términos de los compromisos políticos involucrados y los intereses sociales en juego. Así, los autores proponen un criterio de adaptación que permita rediseñar la tecnosfera para armonizar los procesos biofísicos con el desarrollo social. Estos criterios no solo están orientados a proporcionar soluciones al problema del diseño, sino también deben contribuir a superar el desarrollo geográfico desigual y el cinismo que lo sustenta

Fine-grain circuit hardening through VHDL datatype substitution

Radiation effects can induce, amongst other phenomena, logic errors in digital circuits and systems. These logic errors corrupt the states of the internal memory elements of the circuits and can propagate to the primary outputs, affecting other onboard systems. In order to avoid this, Triple Modular Redundancy is typically used when full robustness against these phenomena is needed. When full triplication of the complete design is not required, selective hardening can be applied to the elements in which a radiation-induced upset is more likely to propagate to the main outputs of the circuit. The present paper describes a new approach for selectively hardening digital electronic circuits by design, which can be applied to digital designs described in the VHDL Hardware Description Language. When the designer changes the datatype of a signal or port to a hardened type, the necessary redundancy is automatically inserted. The automatically hardening features have been compiled into a VHDL package, and have been validated both in simulation and by means of fault injection.Ministerio de Economía y Competitividad ESP2015-68245-C4-2-PComisión Europea ID 687220

Would RC wide-beam buildings in Spain have survived Lorca earthquake (11-05-2011)?

Lorca earthquake (11-05-2011) is most destructive event recorded in Spain, causing nine fatalities and other severe consequences. Its important intensity was rather unexpected, and serious concern arose regarding risk of building stock in Spain. This paper analyzes performance, under Lorca earthquake, of RC buildings with one-way slabs with wide beams. This construction type is chosen for its high vulnerability and for being vastly widespread in Spain. This study is conducted on 3 and 6-story prototype representative buildings. These buildings are designed for three major seismic zones in Spain: low seismicity, moderate seismicity (as Lorca) and medium seismicity (as Granada). Seismic performance under Lorca earthquake is numerically investigated through nonlinear time-history analyses. Results show that buildings designed without any seismic provision (i.e. those in low seismicity zones) do not survive Lorca record, even with cooperation of masonry infill walls. Buildings with seismic design (i.e. those in Lorca and Granada zones) can survive Lorca earthquake only with collaboration of infill walls. To raise reliability of these conclusions, a sensitivity analysis to most influencing parameters is conducted.Postprint (author's final draft