Configurable memory systems for embedded many-core processors

The memory system of a modern embedded processor con- sumes a large fraction of total system energy. We explore a range of different configuration options and show that a reconfigurable design can make better use of the resources available to it than any fixed implementation, and provide large improvements in both performance and energy con- sumption. Reconfigurability becomes increasingly useful as resources become more constrained, so is particularly rele- vant in the embedded space. For an optimised architectural configuration, we show that a configurable cache system performs an average of 20% (maximum 70%) better than the best fixed implementation when two programs are competing for the same resources, and reduces cache miss rate by an average of 70% (maximum 90%). We then present a case study of AES encryption and decryption, and find that a custom memory configuration can almost double performance, with further benefits being achieved by specialising the task of each core when parallelising the program

WH2 and proline-rich domains of WASP-family proteins collaborate to accelerate actin filament elongation.

WASP-family proteins are known to promote assembly of branched actin networks by stimulating the filament-nucleating activity of the Arp2/3 complex. Here, we show that WASP-family proteins also function as polymerases that accelerate elongation of uncapped actin filaments. When clustered on a surface, WASP-family proteins can drive branched actin networks to grow much faster than they could by direct incorporation of soluble monomers. This polymerase activity arises from the coordinated action of two regulatory sequences: (i) a WASP homology 2 (WH2) domain that binds actin, and (ii) a proline-rich sequence that binds profilin-actin complexes. In the absence of profilin, WH2 domains are sufficient to accelerate filament elongation, but in the presence of profilin, proline-rich sequences are required to support polymerase activity by (i) bringing polymerization-competent actin monomers in proximity to growing filament ends, and (ii) promoting shuttling of actin monomers from profilin-actin complexes onto nearby WH2 domains. Unoccupied WH2 domains transiently associate with free filament ends, preventing their growth and dynamically tethering the branched actin network to the WASP-family proteins that create it. Collaboration between WH2 and proline-rich sequences thus strikes a balance between filament growth and tethering. Our work expands the number of critical roles that WASP-family proteins play in the assembly of branched actin networks to at least three: (i) promoting dendritic nucleation; (ii) linking actin networks to membranes; and (iii) accelerating filament elongation

RC-Chord: Resource Clustering in a Large-Scale Hierarchical Peer-to-Peer System

Conducting data fusion and Command and Control (C2) in large-scale systems requires more than the presently available Peer-to-Peer (P2P) technologies provide. Resource Clustered Chord (RC-Chord) is an extension to the Chord protocol that incorporates elements of a hierarchical peer-to-peer architecture to facilitate coalition formation algorithms in large-scale systems. Each cluster in this hierarchy represents a particular resource available for allocation, and RC-Chord provides the capabilities to locate agents of a particular resource. This approach improves upon other strategies by including support for abundant resources, or those resources that most or all agents in the system possess. This scenario exists in large-scale coalition formation problems, and applies directly to the United States Air Force\u27s CyberCraft project. Simulations demonstrate that RC-Chord scales to systems of one million or more agents, and can be adapted to serve as a deployment environment for CyberCraft

Identifying and Quantifying Critical Information Streams for Tactical Combat Decision Modeling

It is often asserted that more information on the battlefield leads to greater situational awareness (SA) which, in turn, translates to enhanced mission performance and outcomes.  However, the volume of available information on the modern networked battlefield is extensive and growing, which induces risk of indecision due to cognitive overload.  The potential overload highlights the need to streamline the flow of information to those critical streams that provide the most value to a tactical leader’s decision process at particular points in time. The purpose of this study is to identify critical information streams required by tactical leaders within the various phases of a dismounted search and attack/react to contact scenario.  Domain Mapping Matrix methodology (DMM) is utilized to quantify the value of various information streams relative to the sub -phases within the scenario using a constructed nominal scale. The significance of the highlighted interactions is validated through the use of statistical analysis, with combat veterans serving as test cases. The findings of this study will facilitate the development of decision models that will eventually enable more accurate and realistic simulation of the leader’s decision processes that increased SA purportedly enhances

Seshat: The Global History Databank

The vast amount of knowledge about past human societies has not been systematically organized and, therefore, remains inaccessible for empirically testing theories about cultural evolution and historical dynamics. For example, what evolutionary mechanisms were involved in the transition from the small-scale, uncentralized societies, in which humans lived 10,000 years ago, to the large-scale societies with an extensive division of labor, great differentials in wealth and power, and elaborate governance structures of today? Why do modern states sometimes fail to meet the basic needs of their populations? Why do economies decline, or fail to grow? In this article, we describe the structure and uses of a massive databank of historical and archaeological information, Seshat: The Global History Databank. The data that we are currently entering in Seshat will allow us and others to test theories explaining how modern societies evolved from ancestral ones, and why modern societies vary so much in their capacity to satisfy their members’ basic human needsPeer reviewedFinal Published versio

Psychotropic Medication Use among Medicare Beneficiaries Following Traumatic Brain Injury

Objectives—To characterize psychotropic medication use before and after traumatic brain injury (TBI) hospitalization among older adults. A secondary objective is to determine how receipt of indicated pharmacologic treatment for anxiety and post-traumatic stress disorder (PTSD) differs following TBI. Design—Retrospective cohort Setting—United States Participants—Medicare beneficiaries age ≥65 hospitalized with TBI 2006-2010 with continuous drug coverage for 12 months before and after TBI (n=60,276). Measurements—We obtained monthly psychotropic medication use by drug class and specific drugs from Medicare Part D drug event files. International Classification of Disease, 9th Edition CM, codes were used to define anxiety (300.0x) and PTSD (309.81). Results—Average monthly prevalence of psychotropic medication use among all patients hospitalized for TBI was 44.8%; antidepressants comprised 73%. Prevalence of psychotropic medication use increased from 2006-2010. Following TBI, psychotropic medication use increased slightly (odds ratio (OR) 1.05; 95% confidence interval (CI) 1.03, 1.06.) Tricyclic antidepressant use decreased post-TBI (OR 0.76; 95% CI 0.73, 0.79) while use of the sedating antidepressants mirtazapine (OR 1.31; 95% CI 1.25, 1.37) and trazadone (OR 1.11; 95% CI 1.06, 1.17) increased. Antipsychotic (OR 1.15; 95% CI 1.12, 1.19) use also increased post-TBI. Beneficiaries newly diagnosed with anxiety (OR 0.42; 95% CI 0.36, 0.48) and/or PTSD (OR 0.39; 95% CI 0.18, 0.84) post-TBI were less likely to receive indicated pharmacologic treatment. Conclusions—Older adults hospitalized with TBI have a high prevalence of psychotropic medication use yet are less likely to receive indicated pharmacological treatment for newly diagnosed anxiety and PTSD following TBI