Virtual Stack Research Articles

Becoming aWARE: The Development of a Web-Based Tool for Autism Research and the Environment.

A sharp rise in autism spectrum disorder (ASD) prevalence estimates, beginning in the 1990s, suggested factors additional to genetics were at play. This stimulated increased research investment in nongenetic factors, including the study of environmental chemical exposures, diet, nutrition, lifestyle, social factors, and maternal medical conditions. Consequently, both peer- and non-peer-reviewed bodies of evidence investigating environmental contributors to ASD etiology have grown significantly. The heterogeneity in the design and conduct of this research results in an inconclusive and unwieldy 'virtual stack' of publications. We propose to develop a Web-based tool for Autism Research and the Environment (aWARE) to comprehensively aggregate and assess these highly variable and often conflicting data. The interactive aWARE tool will use an approach for the development of systematic evidence maps (SEMs) to identify and display all available relevant published evidence, enabling users to explore multiple research questions within the scope of the SEM. Throughout tool development, listening sessions and workshops will be used to seek perspectives from the broader autism community. New evidence will be indexed in the tool annually, which will serve as a living resource to investigate the association between environmental factors and ASD.

Development and evaluation of a novel 3D simulation software for modelling wood stacks.

Assessing the solid wood content is crucial when acquiring stacked roundwood. A frequently used method for this is to multiply determined conversion factors by the measured gross volume. However, the conversion factors are influenced by several log and stack parameters. Although these parameters have been identified and studied, their individual influence has not yet been analyzed using a broad statistical basis. This is due to the considerable financial resources that the data collection entails. To overcome this shortcoming, a 3D-simulation model was developed. It generates virtual wood stacks of randomized composition based on one individual data set of logs, which may be real or defined by the user. In this study, the development and evaluation of the simulation model are presented. The model was evaluated by conducting a sensitivity and a quantitative analysis of the simulation outcomes based on real measurements of 405 logs of Norway spruce and 20 stacks constituted with these. The results of the simulation outcomes revealed a small overestimation of the net volume of real stacks: by 1.2% for net volume over bark and by 3.2% for net volume under bark. Furthermore, according to the calculated mean bias error (MBE), the model underestimates the gross volume by 0.02%. In addition, the results of the sensitivity analysis confirmed the capability of the model to adequately consider variations in the input parameters and to provide reliable outcomes.

Security Threat Modelling With Bayesian Networks and Sensitivity Analysis for IAAS Virtualization Stack

Designing security mechanisms for cloud computing infrastructures has assumed importance with the widespread adoption of public clouds. Virtualization security is a crucial component of the overall cloud infrastructure security. In this article, the authors employ the concept of Bayesian networks and attack graphs to carry out sensitivity analysis on the different components involved in virtualization security for infrastructure as a service (IaaS) cloud infrastructures. They evaluate the Bayesian attack graph (BAG) for the IaaS model to reveal the sensitive regions and thus help the administrators to secure the high risk components in the stack. They present a formal definition of the sensitivity analysis and then evaluate using the BAG model for IaaS stack. The model and analysis presented here can also be used by security analysts and designers to make a selection of the security solutions based on the risk profile of vulnerable nodes and the corresponding cost involved in adding a defense against the identified vulnerabilities.

Rapid perceptual processing in two- and three-dimensional prostate images.

Radiologists can identify whether a radiograph is abnormal or normal at above chance levels in breast and lung images presented for half a second or less. This early perceptual processing has only been demonstrated in static two-dimensional images (e.g., mammograms). Can radiologists rapidly extract the "gestalt" from more complex imaging modalities? For example, prostate multiparametric magnetic resonance imaging (mpMRI) displays a series of images as a virtual stack and comprises multiple imaging sequences: anatomical information from the T2-weighted (T2W) sequence, functional information from diffusion-weighted imaging, and apparent diffusion coefficient sequences. We first tested rapid perceptual processing in static T2W images then among the two functional sequences. Finally, we examined whether this rapid radiological perception could be observed using T2W multislice imaging. Readers with experience in prostate mpMRI could detect and localize lesions in all sequences after viewing a 500-ms static image. Experienced prostate readers could also detect and localize lesions when viewing multislice image stacks presented as brief movies, with image slices presented at either 48, 96, or 144ms. The ability to quickly extract the perceptual gestalt may be a general property of expert perception, even in complex imaging modalities.

Travel Time and Waveform Measurements of Global Multibounce Seismic Waves Using Virtual Station Seismogram Stacks

AbstractWe construct geographically localized bin stacks of waveforms, called virtual stations, to enhance signal‐to‐noise ratios (SNRs) for travel time and waveform measurements of multibounce S and ScS phases (S up to S6 and ScS up to ScS5), as well as direct S, ScS, and Sdiff, on tangential component data. Major arc S and ScS multibounce waves were also measured. Virtual station data are referenced to empirical wavelets constructed from direct S waves for each event. The virtual station approach is useful for low SNR data, bolstering wave path coverage in the southern hemisphere. Goodness of fit measurements between the adapted empirical wavelet and virtual station waveforms are documented, as well as SNRs, allowing for objective definition of travel time measurement quality. From a data set of 360 earthquakes and 8,407 seismographic stations, nearly 4 million records were utilized to construct 248,657 virtual station stacked seismograms, which were compared to best‐fitting empirical wavelets. After human inspection of virtual station results, 8,871 travel time measurements were retained from 19 different minor and major arc seismic wave types. Higher multibounce data improve sampling of the southern hemisphere. From 188,003 single seismograms, 3,331 multibounce wave measurements were also made. Comparisons of single seismogram and virtual station stack measurements show a consistent bias: Virtual stack onset times are systematically early due to a broadening effect from stacking records with arrival time differences, which we correct for. The travel time and waveform measurements are publicly available.

A Tour of the Virtual Stacks

Rows upon rows of “virtual stacks” now stretch as far as the eye can see. From JSTOR to the Library of Congress to Ancestry.com, unprecedented quantities of historical material are being added to the digital ether. In fact, you are probably reading these words on a screen right now. Search-box interfaces allow historians to instantly query vast quantities of historical material in order to pull out information about individuals, events, institutions, and locations. With just a few strokes of a keyboard, a historian can sift through millions of digitized pages of newspapers, government documents, or books. A process that would have once taken a lifetime of flipping through microfilm or archival folders can be conducted in just a few minutes. As historian Lara Putnam notes, this now “feels as revolutionary as oatmeal.” But, she argues, the “mass digitized turn” has nevertheless had a profound impact on the practice of history in ways that the discipline is only beginning to understand. This is especially true for a field like modern American history, where an abundance of easily scannable English-language sources has generated a wealth of online material.

Occlusion calculation algorithm for computer generated hologram based on ray tracing

Computer-generated holograms(CGHs) with occlusion information have a better sense of reality. There is also a reduction in the amount of calculation since the occluded part does not need to be calculated. We made adaptive changes to the traditional graphical ray tracing method and introduced it into CGH to get the correct occlusion effect of point cloud models and achieve fast intersection calculation. To realize the motion parallax effect, the hologram is divided into sub-holograms. A KD-Tree traversal algorithm for a GPU based on the virtual stack is proposed to implement efficient parallel computation in ray tracing. The effectiveness of the proposed algorithm was verified by several experiments in terms of the occlusion effect and motion parallax effect, and its temporal and spatial efficiency was proven.

Sharing Programming Resources Between Bio* Projects.

Open-source software encourages computer programmers to reuse software components written by others. In evolutionary bioinformatics, open-source software comes in a broad range of programming languages, including C/C++, Perl, Python, Ruby, Java, and R. To avoid writing the same functionality multiple times for different languages, it is possible to share components by bridging computer languages and Bio* projects, such as BioPerl, Biopython, BioRuby, BioJava, and R/Bioconductor.In this chapter, we compare the three principal approaches for sharing software between different programming languages: by remote procedure call (RPC), by sharing a local “call stack,” and by calling program to programs. RPC provides a language-independent protocol over a network interface; examples are SOAP and Rserve. The local call stack provides a between-language mapping, not over the network interface but directly in computer memory; examples are R bindings, RPy, and languages sharing the Java virtual machine stack. This functionality provides strategies for sharing of software between Bio* projects, which can be exploited more often.Here, we present cross-language examples for sequence translation and measure throughput of the different options. We compare calling into R through native R, RSOAP, Rserve, and RPy interfaces, with the performance of native BioPerl, Biopython, BioJava, and BioRuby implementations and with call stack bindings to BioJava and the European Molecular Biology Open Software Suite (EMBOSS).In general, call stack approaches outperform native Bio* implementations, and these, in turn, outperform “RPC”-based approaches. To test and compare strategies, we provide a downloadable Docker container with all examples, tools, and libraries included.

Image processing for precise three-dimensional registration and stitching of thick high-resolution laser-scanning microscopy image stacks

The possible depth of imaging of laser-scanning microscopy is limited not only by the working distances of objective lenses but also by image degradation caused by attenuation and diffraction of light passing through the specimen. To tackle this problem, one can either flip the sample to record images from both sides of the specimen or consecutively cut off shallow parts of the sample after taking serial images of certain thickness. Multiple image substacks acquired in these ways should be combined afterwards to generate a single stack. However, subtle movements of samples during image acquisition cause mismatch not only in the translation along x-, y-, and z-axes and rotation around z-axis but also tilting around x- and y-axes, making it difficult to register the substacks precisely. In this work, we developed a novel approach called 2D-SIFT-in-3D-Space using Scale Invariant Feature Transform (SIFT) to achieve robust three-dimensional matching of image substacks. Our method registers the substacks by separately fixing translation and rotation along x-, y-, and z-axes, through extraction and matching of stable features across two-dimensional sections of the 3D stacks. To validate the quality of registration, we developed a simulator of laser-scanning microscopy images to generate a virtual stack in which noise levels and rotation angles are controlled with known parameters. We illustrate quantitatively the performance of our approach by registering an entire brain of Drosophila melanogaster consisting of 800 sections. Our approach is also demonstrated to be extendable to other types of data that share large dimensions and need of fine registration of multiple image substacks. This method is implemented in Java and distributed as ImageJ/Fiji plugin. The source code is available via Github (http://www.creatis.insa-lyon.fr/site7/fr/MicroTools).

Complete simulation process chain for the manufacturing of braided composite parts

A complete simulation process chain has been used to predict the production and subsequent injection of over-braided textile preforms. A range of mandrel geometries and braiding configurations were used to illustrate how these factors affect the resin injection of the part. Braiding simulations were first completed, predicting the geometry of the braided textile throughout the mandrel. Following this, a range of multi-layered unit-cells were modelled, capturing the variations in geometry. These virtual stacks were produced with both no and maximum in-plane ply shift so as to capture the range of stacking configurations possible. Following a compaction simulation of these stacks, their in-plane permeability tensor was predicted and used to identify the permeability of the braided preform at different regions. This was used to predict the propagation of the resin flow front, highlighting the effects that the mandrel geometry, braiding process parameters and stacking method have on the resulting resin injection.

Abstractions for Practical Virtual Machine Replay

Efficient deterministic replay of whole operating systems is feasible and useful, so why isn't replay a default part of the software stack? While implementing deterministic replay is hard, we argue that the main reason is the lack of general abstractions for understanding and addressing the significant engineering challenges involved in the development of a replay engine for a modern VMM. We present a design blueprint---a set of abstractions, general principles, and low-level implementation details---for efficient deterministic replay in a modern hypervisor. We build and evaluate our architecture in Xen, a full-featured hypervisor. Our architecture can be readily followed and adopted, enabling replay as a ubiquitous part of a modern virtualization stack.

A Conceptual Design of Job Pre-processing Flow for Heterogeneous Batch Systems in Data Center

Processing a workflow (or a job) created by a user, who can be a researcher from a scientific laboratory or an analysis from a commercial organization, is the main functionality that a data center or a high-performance computing center is generally expected to provide. It can be accomplished with a single core processor and rather small amount of memory if the problem is adequately small while it may require thousands of nodes to solve a complicated problem and peta-bytes of storage for its output. Also specific applications on various platforms are required in general by users for resolving the problems appropriately. In this aspect, a data center should operate non-homogeneous systems for resource management, so-called batch system, in which it results in inefficient resource utilization due to stochastic behavior of user activity. Implementation of virtualization for resource management, e.g. Cloud Computing, is one of promising solutions recently arising, however, it results in the increase of complexity of the system itself as well as the system administration because it naturally implies the intervention of virtualization stack, e.g. hypervisor, between Operating System and applications for resource management. In this paper, we propose a new conceptual design to be implemented as a pre-scheduler capable to insert user submitted jobs dedicated to a specific batch system into available resources managed by other kind of batch systems. The proposed design features transparency in between clients and batch systems, accuracy in terms of monitoring and prediction on the available resources, and scalability for additional batch systems. We suggest the implementation example of the conceptual design based on the scenario established from our experience of operating a data center.

자동서고의 자료 수장 효율성에 관한 연구

This study aims to compare the retention efficiency of library materials of Automated Storage and Retrieval System(AS/RS) revealed by the literature review to other types of book stacks. Domestic and foreign academic libraries adopted AS/RS as part of a plan to improve the retention efficiency. Literature review reveals that in general, AS/RS is better in the retention efficiency in compare to other types of book stacks. This study compared the amount of library materials stored by the AS/RS of S University Library to the general book stack and the fixed-type and the mobile rack-type of virtual book stacks. The study reveals that AS/RS is up to 6 times more efficient than general book stacks, up to 3.61 times more efficient than fixed-type book stacks and up to 1.45 times more efficient than mobile rack-type book stacks. However, the study claims that the retention efficiency of library materials of AS/RS is lower than what is known.

Working in the Virtual Stacks: The New Library and Information Science

Working in the Virtual Stacks: The New Library and Information Science

Book review: Laura Townsend Kane, Working in the virtual stacks: The new library and information science

Book review: Laura Townsend Kane, Working in the virtual stacks: The new library and information science

Design and Analysis of AFDX Network Based High-Speed Avionics System of Civil Aircraft

Avionics Full Duplex Switched Ethernet (AFDX) standardized as ARINC 664 is a major upgrade for integrated avionics systems of civil aircraft. It becomes the current communication technology in the context of avionics and provides a backbone network for the civil avionics system. This paper focuses on features of AFDX network protocol. Architecture of AFDX switch based on shared memory is proposed to meet the requirements of avionics real-time system. In addition, frame filtering, traffic policing and frame schedule function are used to eliminate uncertainties in huge traffic flows. End System (ES) host-target architecture is also researched in this paper. Virtual link scheduler, redundancy management, and protocol stack in ES are designed to ensure determinism and reliability of data communication. AFDX switch and ES have been successfully developed, and configuration tool, ARINC 615A loader and simulation tool related to AFDX network are also provided as package solution to support avionics system construction. Finally, AFDX switch and ESes have passed ARINC 664 protocol conformance test and certification, the test results show that our AFDX products meet the requirements of real-time communication, determinism and reliability defined in ARINC 664

Asymptotically Reduced Model for a Proton Exchange Membrane Fuel Cell Stack: Automated Model Generation and Verification

A proton exchange membrane fuel cell (PEMFC) stack can comprise a large number of cells and coolant plates; the former, in turn, contain further functional layers and groups. The large number of transport phenomena that occur at differing length scales throughout the stack pose a challenging problem for mathematical modeling. In this context, we present a “bottom-up” approach to overcome the difficulties in the mathematical modeling of a PEMFC stack; in short, a fast and memory-efficient reduced model for a single PEMFC derived earlier is coupled to a model for heat and charge transfer in a coolant plate to form a numerical building block, which can be replicated to form a virtual stack having the required number of cells. This procedure is automated to avoid the time-consuming task of manually creating the stack, as well as to remove the possibility of human error during the setup phase. The automated, reduced stack model is verified for a 10-cell stack with the full set of equations; good agreement is found when perturbations between cells are “small.” We then study the computational efficiency of the reduced model for stacks comprising up to 400 cells: A typical run for a 10-cell and a 100-cell stack takes around 20 s and 3–4 min and requires 0.6 and 1.2 GB of random access memory, respectively. Finally, extensions to include the effects of perturbed flow, additional physics, external manifolds, and other types of flow fields are discussed.

Virtual machine showdown

Virtual machines (VMs) enable the distribution of programs in an architecture-neutral format, which can easily be interpreted or compiled. A long-running question in the design of VMs is whether a stack architecture or register architecture can be implemented more efficiently with an interpreter. We extend existing work on comparing virtual stack and virtual register architectures in three ways. First, our translation from stack to register code and optimization are much more sophisticated. The result is that we eliminate an average of more than 46% of executed VM instructions, with the bytecode size of the register machine being only 26% larger than that of the corresponding stack one. Second, we present a fully functional virtual-register implementation of the Java virtual machine (JVM), which supports Intel, AMD64, PowerPC and Alpha processors. This register VM supports inline-threaded, direct-threaded, token-threaded, and switch dispatch. Third, we present experimental results on a range of additional optimizations such as register allocation and elimination of redundant heap loads. On the AMD64 architecture the register machine using switch dispatch achieves an average speedup of 1.48 over the corresponding stack machine. Even using the more efficient inline-threaded dispatch, the register VM achieves a speedup of 1.15 over the equivalent stack-based VM.

모바일 코드를 이용한 최적적응 침입탐지시스템

A damage scale of information property has been increasing rapidly by various illegal actions of information systems, which result from dysfunction of a knowledge society. Reinforcement in criminal investigation requests of network security has accelerated research and development of Intrusion Detection Systems(IDSs), which report intrusion-detection about these illegal actions. Due to limited designs of early IDSs, it is hard for the IDSs to cope with tricks to go around IDS as well as false-positive and false-negative trials in various network environments. In this paper, we showed that this kind of problems can be solved by using a Virtual Protocol Stack(VPS) that possesses automatic learning ability through an optimum-adaptive mobile code. Therefore, the enhanced IDS adapts dynamically to various network environments in consideration of monitored and self-learned network status. Moreover, it is shown that Insertion/Evasion attacks can be actively detected. Finally, we discussed that this method can be expanded to an intrusion detection technique that possesses adaptability in the various mixed network environments.

Virtual stacks: Storing and using electronic journals

Although some interim de facto standards, such as the Internet interface and Portable Document Format(PDF), are emerging amongst the ever changing systems for the storage and dissemination of electronic information, many issues, including interoperability, metadata description and persistence in document identifiers, remain to be resolved. However, an information supplier like the British Library cannot wait for total system stability, and it has set up a trial document store, using both a local datastore and working with commercial suppliers on access to external data sources. Such co-operation may produce the practical solutions which are viable in the longer term.