Algorithm-Directed Crash Consistence in Non-Volatile Memory for HPC

Fault tolerance is one of the major design goals for HPC. The emergence of non-volatile memories (NVM) provides a solution to build fault tolerant HPC. Data in NVM-based main memory are not lost when the system crashes because of the non-volatility nature of NVM. However, because of volatile caches, data must be logged and explicitly flushed from caches into NVM to ensure consistence and correctness before crashes, which can cause large runtime overhead. In this paper, we introduce an algorithm-based method to establish crash consistence in NVM for HPC applications. We slightly extend application data structures or sparsely flush cache blocks, which introduce ignorable runtime overhead. Such extension or cache flushing allows us to use algorithm knowledge to \textit{reason} data consistence or correct inconsistent data when the application crashes. We demonstrate the effectiveness of our method for three algorithms, including an iterative solver, dense matrix multiplication, and Monte-Carlo simulation. Based on comprehensive performance evaluation on a variety of test environments, we demonstrate that our approach has very small runtime overhead (at most 8.2\% and less than 3\% in most cases), much smaller than that of traditional checkpoint, while having the same or less recomputation cost.Comment: 12 page

Toward Smart Moving Target Defense for Linux Container Resiliency

This paper presents ESCAPE, an informed moving target defense mechanism for cloud containers. ESCAPE models the interaction between attackers and their target containers as a "predator searching for a prey" search game. Live migration of Linux-containers (prey) is used to avoid attacks (predator) and failures. The entire process is guided by a novel host-based behavior-monitoring system that seamlessly monitors containers for indications of intrusions and attacks. To evaluate ESCAPE effectiveness, we simulated the attack avoidance process based on a mathematical model mimicking the prey-vs-predator search game. Simulation results show high container survival probabilities with minimal added overhead.Comment: Published version is available on IEEE Xplore at http://ieeexplore.ieee.org/document/779685

Feasibility and preliminary efficacy of remotely delivering cognitive training to people with schizophrenia using tablets.

Limited access to Cognitive Training (CT) for people with schizophrenia (SZ) prevents widespread adoption of this intervention. Delivering CT remotely via tablets may increase accessibility, improve scheduling flexibility, and diminish patient burden.In this reanalysis of data from a larger trial of CT, we compared two samples of individuals with SZ who chose to complete 40 h of CT either on desktop computers in the laboratory (N = 33) or remotely via iPads (N = 41). We examined attrition rates and adherence to training, and investigated whether remote iPad-based CT and in-person desktop-based CT induced significantly different improvements in cognitive and real-world functioning.The attrition rate was 36.6%. On average, participants completed 3.06 h of CT per week. There were no significant between-group differences in attrition and adherence to CT requirements. Participants who completed iPad-based CT were significantly younger and had lower symptoms at baseline compared to participants who completed CT on the lab desktops. Controlling for age and symptom severity, rANCOVA showed that iPad-based and desktop-based CT similarly and significantly improved verbal learning and problem solving. Main effects of time, at trend level significance, were evident in global cognition, verbal memory, quality of life, and social functioning. All group by time interactions were non-significant except for verbal memory, where iPad users showed greater gains. Within-group effect sizes for changes in outcomes were in the small range.Although underpowered and not randomized, this study demonstrates that delivering CT remotely to people with SZ using tablets is feasible and results in retention rates, adherence, and cognitive and functional outcome improvements that are comparable to those observed when CT is delivered in the laboratory. This has important implications in terms of scalability and dissemination of CT. These results require confirmation in larger samples

Adverse Aftereffects of Methotrexate as Chemotherapy on Cognitive Deficits in Rat Models

Patients with acute lymphoblastic leukemia have a high five-year survival rate thanks to methotrexate (MTX). However, cognitive side effects are reported, characterized as chemo brain. The study investigated if impulsiveness is part of the aberrant cognitive functions after being exposed to MTX in the early stage of physical development. Adolescent rats were injected with either phosphate-buffered saline (PBS) or MTX. The novel object recognition (NOR) task was conducted a month after the injections to measure the memory deficits. The discounting task was performed after the rats completed training on a fixed-ratio one schedule for both levers. The NOR test showed both the PBS and MTX rats recognized the novel object; however, the PBS group spent more time inspecting the novel object than the MTX group. Initial results from two rats (one from each group) for the discounting task showed that the PBS-treated rat preferred the immediate reward at the beginning and had increased omissions during the later trials. The MTX rat showed a consistent preference for the immediate lever across the entire procedure. These composite findings suggested cognitive deficits are not apparent within one month of MTX treatment, yet the impulsiveness is more apparent after MTX exposure