Stopping time signatures for some algorithms in cryptography

We consider the normalized distribution of the overall running times of some cryptographic algorithms, and what information they reveal about the algorithms. Recent work of Deift, Menon, Olver, Pfrang, and Trogdon has shown that certain numerical algorithms applied to large random matrices exhibit a characteristic distribution of running times, which depends only on the algorithm but are independent of the choice of probability distributions for the matrices. Different algorithms often exhibit different running time distributions, and so the histograms for these running time distributions provide a time-signature for the algorithms, making it possible, in many cases, to distinguish one algorithm from another. In this paper we extend this analysis to cryptographic algorithms, and present examples of such algorithms with time-signatures that are indistinguishable, and others with time-signatures that are clearly distinct.Comment: 20 page

A new hardware architecture for genomic and proteomic sequence alignment

Los Alamitos, US

DASH: localising dynamic programming for order of magnitude faster, accurate sequence alignment

Los Alamitos, US

Systematic Analysis of Clinical Outcomes Following Stereotactic Radiosurgery for Central Neurocytoma.

Central neurocytoma (CN) typically presents as an intraventricular mass causing obstructive hydrocephalus. The first line of treatment is surgical resection with adjuvant conventional radiotherapy. Stereotactic radiosurgery (SRS) was proposed as an alternative therapy for CN because of its lower risk profile. The objective of this systematic analysis is to assess the efficacy of SRS for CN. A systematic analysis for CN treated with SRS was conducted in PubMed. Baseline patient characteristics and outcomes data were extracted. Heterogeneity and publication bias were also assessed. Univariate and multivariate linear regressions were used to test for correlations to the primary outcome: local control (LC). The estimated cumulative rate of LC was 92.2% (95% confidence interval: 86.5-95.7%, p<0.001). Mean follow-up time was 62.4 months (range 3-149 months). Heterogeneity and publication bias were insignificant. The univariate linear regression models for both mean tumor volume and mean dose were significantly correlated with improved LC (p<0.001). Our data suggests that SRS may be an effective and safe therapy for CN. However, the rarity of CN still limits the efficacy of a quantitative analysis. Future multi-institutional, randomized trials of CN patients should be considered to further elucidate this therapy

Disability Rights Mandates: Federal and State Compliance with Employment Protection and Architectural Barrier Removal

The findings of this study indicate that the existence of national mandates does not necessarily eliminate the need for citizen groups to be attentive to state capitols and city halls. Ironically, one factor in the rise of regulatory federalism has been the desire of interest groups to concentrate their resources on one government, namely, the national government, rather than 50 different state governments. Yet, success in the national arena is often only partial, and sometimes only largely symbolic. It is the implementation of national rules that takes one back to states and localities. The findings of this study also suggest that problems of policy implementation that are often attributed to intergovernmental obstacles may be as much or more due to intragovernmental obstacles. The rise of regulatory federalism has been fueled by a belief that it is better to have one government rather than 50 governments perform functions. One government can presumably formulate rational and coherent policy, and then coordinate the efficient implementation of that policy, thus avoiding the fragmentation and diversity often said to be characteristic of intergovernmental policy implementation. Yet, the problem with this theory is that intergovernmental fragmentation, which may not be the real issue in every case, may simply be replaced by intragovernmental fragmentation. As more responsibilities are assigned to one government, intragovernmental fragmentation is likely to be exacerbated. What needs to be explored, then, is how intergovernmental policymaking may be, under many circumstances, a more effective way to achieve essential national objectives than purely national policymaking in which compliance requirements are more prominent than alliance incentives. Another issue to be addressed is whether the federal government is as equally willing and able to impose sanctions on its own agencies for noncompliance as it is to impose sanctions on state and local governments. Federal agencies and courts may levy fines, withhold grant funds, or compel state and local governments to alter funding priorities or raise new revenue in order to enforce compliance with national mandates. Would the Congress or the President be prepared, let us say, to withhold 10 percent of the Defense Department\u27s funding in order to compel compliance if the department were not in full compliance with certain mandates applicable to federal agencies? Is the U.S. Supreme Court prepared to compel the Congress and the President to raise taxes to ensure federal compliance with mandates? Does the Congress itself ensure that its own rules and procedures conform to legislated mandates? Finally, the findings of this study suggest that there is a continuing need to build consensus in the intergovernmental system in order to implement policy nationwide. It is not enough to enact mandates more or less unilaterally and to expect compliance to flow swiftly in their wake. Another factor in the rise of regulatory federalism has been the desire of pressure groups to circumvent or override the many veto points said to exist in the federal system. The price of this strategy, however, can be high, including policy ambiguity and the lack of a sufficiently strong consensus to follow through on vigorous implementation. Policy mandates need to be owned, or at least not disowned, by those who must implement them. Thus, bringing federalism back into the national policy-making process can improve the implementation of policy in what must necessarily be an intergovernmental process. The findings and recommendations were approved by the Commission at its meeting on March 10, 1989

The pinprick approach: Whitehall’s top-secret anti-communist committee and the evolution of British covert action strategy

This article examines Great Britain’s approach to covert action during the formative years of British Cold War intelligence operations, 1950–1951. Rather than shy away from such activity in the wake of the failure in Albania in the late 1940s, the British increased the number of operations they pursued. This was the start of a coherent strategy regarding covert activity that can be conceptualized as the “pinprick” approach. The strategy was overseen by a highly secretive Whitehall body, the Official Committee on Communism, which in effect became the government’s covert action committee. This article uses the commission’s recently declassified papers for the first time to assess the merits of this approach

Application of a single-objective, hybrid genetic algorithm approach to pharmacokinetic model building.

A limitation in traditional stepwise population pharmacokinetic model building is the difficulty in handling interactions between model components. To address this issue, a method was previously introduced which couples NONMEM parameter estimation and model fitness evaluation to a single-objective, hybrid genetic algorithm for global optimization of the model structure. In this study, the generalizability of this approach for pharmacokinetic model building is evaluated by comparing (1) correct and spurious covariate relationships in a simulated dataset resulting from automated stepwise covariate modeling, Lasso methods, and single-objective hybrid genetic algorithm approaches to covariate identification and (2) information criteria values, model structures, convergence, and model parameter values resulting from manual stepwise versus single-objective, hybrid genetic algorithm approaches to model building for seven compounds. Both manual stepwise and single-objective, hybrid genetic algorithm approaches to model building were applied, blinded to the results of the other approach, for selection of the compartment structure as well as inclusion and model form of inter-individual and inter-occasion variability, residual error, and covariates from a common set of model options. For the simulated dataset, stepwise covariate modeling identified three of four true covariates and two spurious covariates; Lasso identified two of four true and 0 spurious covariates; and the single-objective, hybrid genetic algorithm identified three of four true covariates and one spurious covariate. For the clinical datasets, the Akaike information criterion was a median of 22.3 points lower (range of 470.5 point decrease to 0.1 point decrease) for the best single-objective hybrid genetic-algorithm candidate model versus the final manual stepwise model: the Akaike information criterion was lower by greater than 10 points for four compounds and differed by less than 10 points for three compounds. The root mean squared error and absolute mean prediction error of the best single-objective hybrid genetic algorithm candidates were a median of 0.2 points higher (range of 38.9 point decrease to 27.3 point increase) and 0.02 points lower (range of 0.98 point decrease to 0.74 point increase), respectively, than that of the final stepwise models. In addition, the best single-objective, hybrid genetic algorithm candidate models had successful convergence and covariance steps for each compound, used the same compartment structure as the manual stepwise approach for 6 of 7 (86 %) compounds, and identified 54 % (7 of 13) of covariates included by the manual stepwise approach and 16 covariate relationships not included by manual stepwise models. The model parameter values between the final manual stepwise and best single-objective, hybrid genetic algorithm models differed by a median of 26.7 % (q₁ = 4.9 % and q₃ = 57.1 %). Finally, the single-objective, hybrid genetic algorithm approach was able to identify models capable of estimating absorption rate parameters for four compounds that the manual stepwise approach did not identify. The single-objective, hybrid genetic algorithm represents a general pharmacokinetic model building methodology whose ability to rapidly search the feasible solution space leads to nearly equivalent or superior model fits to pharmacokinetic data

Characteristics and treatments of large cystic brain metastasis: radiosurgery and stereotactic aspiration.

Brain metastasis represents one of the most common causes of intracranial tumors in adults, and the incidence of brain metastasis continues to rise due to the increasing survival of cancer patients. Yet, the development of cystic brain metastasis remains a relatively rare occurrence. In this review, we describe the characteristics of cystic brain metastasis and evaluate the combined use of stereotactic aspiration and radiosurgery in treating large cystic brain metastasis. The results of several studies show that stereotactic radiosurgery produces comparable local tumor control and survival rates as other surgery protocols. When the size of the tumor interferes with radiosurgery, stereotactic aspiration of the metastasis should be considered to reduce the target volume as well as decreasing the chance of radiation induced necrosis and providing symptomatic relief from mass effect. The combined use of stereotactic aspiration and radiosurgery has strong implications in improving patient outcomes