When is a container a comonad?

Abbott, Altenkirch, Ghani and others have taught us that many parameterized datatypes (set functors) can be usefully analyzed via container representations in terms of a set of shapes and a set of positions in each shape. This paper builds on the observation that datatypes often carry additional structure that containers alone do not account for. We introduce directed containers to capture the common situation where every position in a data-structure determines another data-structure, informally, the sub-data-structure rooted by that position. Some natural examples are non-empty lists and node-labelled trees, and data-structures with a designated position (zippers). While containers denote set functors via a fully-faithful functor, directed containers interpret fully-faithfully into comonads. But more is true: every comonad whose underlying functor is a container is represented by a directed container. In fact, directed containers are the same as containers that are comonads. We also describe some constructions of directed containers. We have formalized our development in the dependently typed programming language Agda

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

Method prevents secondary radiation in radiographic inspection

Thin-walled neoprene containers prevent secondary radiation, scatter, and undercut during radiographic inspection. The containers are filled with a mixture of barium sulfate, red lead, and petroleum jelly that achieves the required absorption rate

Software Architecture Risk Containers

Our motivation is to determine whether risks such as im- plementation error-proneness can be isolated into three types of con- tainers at design time. This paper identifies several container candidates in other research that fit the risk container concept. Two industrial case studies were used to determine which of three container types tested is most effective at isolating and predicting at design time the risk of im- plementation error-proneness. We found that Design Rule Containers were more effective than Use Case and Resource Containers

Evaluation of containers as a virtualisation alternative for HEP workloads

In this paper the emerging technology of Linux containers is examined and evaluated for use in the High Energy Physics (HEP) community. Key technologies required to enable containerisation will be discussed along with emerging technologies used to manage container images. An evaluation of the requirements for containers within HEP will be made and benchmarking will be carried out to asses performance over a range of HEP workflows. The use of containers will be placed in a broader context and recommendations on future work will be given

Compact assembly generates plastic foam, inflates flotation bag

Device for generating plastic foam consists of an elastomeric bag and two containers with liquid resin and a liquid catalyst. When the walls of the containers are ruptured the liquids come into contact producing foam which inflates the elastomeric bag

High-density support matrices: Key to the deep borehole disposal of spent nuclear fuel

Deep (4–5 km) boreholes are emerging as a safe, secure, environmentally sound and potentially cost-effective option for disposal of high-level radioactive wastes, including plutonium. One reason this option has not been widely accepted for spent fuel is because stacking the containers in a borehole could create load stresses threatening their integrity with potential for releasing highly mobile radionuclides like 129I before the borehole is filled and sealed. This problem can be overcome by using novel high-density support matrices deployed as fine metal shot along with the containers. Temperature distributions in and around the disposal are modelled to show how decay heat from the fuel can melt the shot within weeks of disposal to give a dense liquid in which the containers are almost weightless. Finally, within a few decades, this liquid will cool and solidify, entombing the waste containers in a base metal sarcophagus sealed into the host rock

Second report on containers

In our first report on containers published in January,1967, we tried to summarise progress in this new mode of transportation and to define some of the problems which existed