EasyScienceGateway: A new framework for providing reproducible user environments on science gateways

Science gateways have become a core part of the cyberinfrastructure ecosystem by increasing access to computational resources and providing community platforms for sharing and publishing education and research materials. While science gateways represent a promising solution for computational reproducibility, common methods for providing users with their user environments on gateways present challenges which are difficult to overcome. This article presents EasyScienceGateway: a new framework for providing user environments on science gateways to resolve these challenges, provides the technical details on implementing the framework on a science gateway based on Jupyter Notebook, and discusses our experience applying the framework to the CyberGIS-Jupyter and CyberGIS-Jupyter for Water gateways.     

From Lesson Learned to the Refactoring of the DRIHM Science Gateway for Hydro-meteorological Research

A full hydro-meteorological (HM) simulation, from rainfall to impact on urban areas, is a multidisciplinary activity which consists in the execution of a workflow composed by complex and heterogeneous model engines. Moreover an extensive set of configuration parameters have to be selected consistently among the models, otherwise the simulation can fail or produce unreliable results. The DRIHM portal is a Web-based science gateway aiming to support HM researchers in designing, executing and managing HM simulations. The first version of the portal was developed during the DRIHM project using the gUSE science gateway toolkit. The lesson we learned is guiding a refactoring process that, together with a review of the most relevant technologies for the development of a science gateway, represent the focus of this paper. Beside the technological aspects, the need of a strong interplay between ICT and other domain-specific communities clearly emerged, together with coherent policies in the management of data, computational resources and software components that represent the ecosystem of a science gateways.     

Enabling Workflow-Oriented Science Gateways to Access Multi-Cloud Systems

In this paper we present a solution to cloud-enable workflow-oriented science gateways. The integration mechanism described in the paper is a generic method that can be followed by other gateway developers. The paper describes the principles and the concrete ways to integrate science gateways with multi-cloud systems. The concrete example to demonstrate the integration principles builds on the integration of WS-PGRADE/gUSE and the CloudBroker Platform (CBP). The integration of WS-PGRADE and the CloudBroker Platform offers a complete cloud-enabled science gateway platform for a diverse set of use-cases and user communities, with the availability to use mainstream cloud middleware types and services (Amazon, IBM, OpenStack, OpenNebula). The advantage of the integrated WS-PGRADE and CloubBroker Platform system is that if a domain-specific science gateway is customized from WS-PGRADE gateway framework it immediately inherits this cloud access flexibility, i.e. the user community of that gateway can access all the cloud types enabled by the integrated system presented.     

TCP／IP网络远程互连研究

网络互连在目前是一个十分活跃的研究课题。网际互连通常采用网桥、路由器或网关实现，而这些网桥、路由器或网关之间有多种连接方式，Ｘ．２５ＰＤＮ是一个现实的选择。本文针对ＴＣＰ／ＩＰ局域网远程互连的需求，详细讨论了ＴＣＰ／ＩＰ局域网与Ｘ．２５公共数据网网关的协议配置及体系结构，并进而讨论了实用网关中的一些技术难点。     

Distributed Application Runtime Environment (DARE): A Standards-based Middleware Framework for Science-Gateways

Gateways have been able to provide efficient and simplified access to distributed and high-performance computing resources. Gateways have been shown to support many common and advanced requirements, as well as proving successful as a shared access mode to production cyberinfrastructure such as the TG/XSEDE. There are two primary challenges in the design of effective and broadly-usable gateways: the first revolves around the creation of interfaces that catpure existing and future usage modes so as to support desired scientific investigation. The second challenge and the focus of this paper, is concerned about the requirement to integrate the user-interfaces with computational resources and specialized cyberinfrastructure in an interoperable, extensible and scalable fashion. Currently, there does not exist a commonly usable middleware to that enables seamless integration of different gateways to a range of distributed and high-performance infrastructures. The development of multiple similar gateways that can work over a range of production cyberinfrastructures, usage modes and application requirements is not scalable without a effective and extensible middleware. Some of the challenges that make using production cyberinfrastructure as a collective resource difficult are also responsible for the absence of middleware that enables multiple gateways to utilize the collective capabilities. We introduce the SAGA-based, Distributed Application Runtime Environment (DARE) framework, using which gateways that seamlessly and effectively utilize scalable distributed infrastructure can be built. We discuss the architecture of DARE-based gateways, and show using several different prototypes—DARE-HTHP, DARE-NGS, how gateways can be constructed by utilizing the DARE middleware framework.     

基于通用家庭网关的智能家庭网络

本文先简要介绍了几种实现家度网络智能化的服务发现技术，分析了这几种技术在实现智能化家度网络时存在的弊端；其后针对这些弊端提出新的基于通用家庭网关实现智能家庭网络的方案，并重点研究了应用在通用家庭网关中的中间件技术。     

Assessing the Usability of a Science Gateway for Medical Knowledge Bases with TRENCADIS

Biomedical applications are often built on top of knowledge bases that contain medical images and clinical reports. Currently, these bases are being used to improve diagnosis, research and teaching, but in many cases, the infrastructure required has a prohibitive cost for many medical centres. However, resources can be attached from existing e-Science infrastructures. Therefore, many efforts have been made to establish best practices that allow the use of such infrastructures. However, e-Science relies on open, distributed, collaborative environments, built on top of very specialized technologies, such as Grid and Cloud computing, which require reasonable technical skills for their usage. Therefore, science gateways have become essential tools that assist users in interacting with e-Science applications. This paper describes TRENCADIS, a technology that supports the creation and operation of virtual knowledge bases. To this end, it provides developers with components and APIs for building secure data services that can be annotated and queried through ontology templates, based on DICOM and DICOM-SR. This technology was used in this paper to build a gateway for assisting diagnosis and research in breast cancer. We also present here the results of a study conducted to evaluate the gateway, from the point of view of the usability perceived by a group of physicians and radiologists.     

无线传感器网络与TD-SCDMA接入网关的设计与实现

根据目前无线传感器网络的发展趋势以及3G网络的大面积推广,本文将嵌入式技术、无线传感器网络、TD-SCDMA通信技术有机结合,选用基于32位ARM9核的S3C2440嵌入式微处理为核心,移植Linux操作系统,设计完成了WSN/TD-SCDMA网关,并应用多个无线传感器节点进行组网测试。测试结果验证了网关功能的完备性,实现了无线传感器网络与TD-SCDMA网络的信息接入与共享。     

Extending Science Gateway Frameworks to Support Big Data Applications in the Cloud

Cloud computing offers massive scalability and elasticity required by many scientific and commercial applications. Combining the computational and data handling capabilities of clouds with parallel processing also has the potential to tackle Big Data problems efficiently. Science gateway frameworks and workflow systems enable application developers to implement complex applications and make these available for end-users via simple graphical user interfaces. The integration of such frameworks with Big Data processing tools on the cloud opens new opportunities for application developers. This paper investigates how workflow systems and science gateways can be extended with Big Data processing capabilities. A generic approach based on infrastructure aware workflows is suggested and a proof of concept is implemented based on the WS-PGRADE/gUSE science gateway framework and its integration with the Hadoop parallel data processing solution based on the MapReduce paradigm in the cloud. The provided analysis demonstrates that the methods described to integrate Big Data processing with workflows and science gateways work well in different cloud infrastructures and application scenarios, and can be used to create massively parallel applications for scientific analysis of Big Data.     

The Essential Components of a Successful Galaxy Service

Driven by advances in data generation technologies and fuelled by radical reduction in costs, genomics has become a data science. Nonetheless the field of genomics has been restrained by the ability to analyse data. Science gateways, such as Galaxy, have the potential to enable bench biologists to analyse their own data without needing be familiar with the command line. Implementing a production scale Galaxy service, sufficiently well-featured and resourced to meet the needs of the end-users, is a significant undertaking and requires the consideration and combination of a number of factors to be successfully adopted by the community. In this paper, we describe the process that we undertook to implement a Galaxy service and describe what we consider to be the essential components of such a service. Our experience and insights will be of interest to those who are planning on implementing a science gateway service in a research organisation.     

Deconstructing and reconstructing: Transforming primary science learning via a mobilized curriculum

The history of science education reform has been fundamentally centered around science curriculum development and implementation. The advent of mobile technologies has necessitated a re-examination of how students could better learn science through these 21st century tools. Conventional teaching materials may not prepare students to learn the inquiry way and to become self-directed and social learners who could learn “everywhere and all the time (seamlessly)” using mobile technologies. This paper is based on our first year of work in our mobile learning research project in transforming primary three science lessons into a “mobilized” curriculum for a classroom context in which students routinely use mobile technologies. Using an exemplar fungi topic, we discuss our approach as well as experiences in deconstructing and reconstructing an existing curriculum through a co-design approach with teachers in a Singapore local school. In doing so, we make a contribution to the methodology for developing mobilized science curricula for in-class learning that also extends to out-of-class learning.     

Using Science Gateways for Bridging the Differences between Research Infrastructures

Researchers can perform large-scale analyses on diverse computing and data infrastructures such as NGIs (National Grid Infrastructures), XSEDE (Extreme Science and Engineering Discovery Environment) and PRACE (Partnership for Advanced Computing in Europe). Some are national like NGIs and XSEDE, some are international like PRACE and all of them require a more or less restrictive application process to get access to resources. Science gateways integrating diverse infrastructures provide the possibility to re-use methods independent of such underlying infrastructures and thus potentially deliver the technical prerequisite for creating reproducible science. To achieve this goal, science gateways have to be integrated seamlessly with security mechanisms and job, data as well as workflow management of the targeted resources. This paper gives an overview on general findings for porting science gateways as well as the challenges faced for porting the German MoSGrid science gateway (Molecular Simulation Grid) to exploit XSEDE and PRACE infrastructures.     

WS-PGRADE/gUSE Generic DCI Gateway Framework for a Large Variety of User Communities

The WS-PGRADE/gUSE generic DCI gateway framework has been developed to support a large variety of user communities. It provides a generic purpose, workflow-oriented graphical user interface to create and run workflows on various DCIs including clusters, Grids, desktop Grids and clouds. The framework can be used by NGIs to support small user communities who cannot afford to develop their own customized science gateway. The WS-PGRADE/gUSE framework also provides two API interfaces (Application Specific Module API and Remote API) to create application-specific science gateways according to the needs of different user communities. The paper describes in detail the workflow concept of WS-PGRADE, the DCI Bridge service that enables access to most of the popular European DCIs and the Application Specific Module and Remote API concepts to generate application-specific science gateways.     

The synergistic integration of mathematics, software engineering, and user-centred design: exploring new trends in education

There is an increasing recognition in the society that interdisciplinary challenges must be part of new educational practices. In this paper, we describe the key curriculum activities at the University of Southern Denmark that combine mathematical modelling, software engineering, and user-centred design courses. These three disciplines represent a core of our graduate program, aiming at educating the professionals that will be capable of not only using but also further developing new technologies, and therefore, will be capable of fostering further the progress in computational science and engineering. Finally, we show how the learning environment, with emphases on broadening the student experience by industrial links, affects the student career aspiration.     

A Duty Cycle-Based Gateway Selection Algorithm for LoRaWAN Downlink Communication

Long Range Wide Area Network (LoRaWAN) has been developed to meet the requirements for the enormous device-to-device communication of Internet of Things (IoT) networks, which consist of a large number of participating devices spread over large coverage areas with low data rates and low power consumption. It supports communications in both directions, uplink, and downlink directions. However, the downlink communication in the current LoRaWAN raises the bottleneck issue at gateways due to the used gateway selection algorithm. This paper proposes a novel gateway selection algorithm based on the duty cycle time-off values for the existing gateways, Duty Cycle Gateway Selection (DCGS), to direct acknowledgment packets as downlink traffic towards the most suitable gateway. Thus, the proposed system avoids subsequent retransmission of previously sent traffic that leads to excessive traffic overloading the network. The proposed system avoids exhausting a gateway duty cycle with downlink traffic by distributing the downlink traffic among available gateways based on the duty cycle time off. DCGS is evaluated using FloRa and INET frameworks in the well-known network simulator OMNeT++. The result shows the superior performance of the proposed approach over the existing Signal-to-Noise ratio (SNR) based selection mechanism. It clearly indicates that the DCGS maintains a better confirmed packet delivery rate while reducing number of retransmissions, collisions, and power consumption.     

Software architectures to integrate workflow engines in science gateways

Science gateways often rely on workflow engines to execute applications on distributed infrastructures. We investigate six software architectures commonly used to integrate workflow engines into science gateways. In tight integration, the workflow engine shares software components with the science gateway. In service invocation, the engine is isolated and invoked through a specific software interface. In task encapsulation, the engine is wrapped as a computing task executed on the infrastructure. In the pool model, the engine is bundled in an agent that connects to a central pool to fetch and execute workflows. In nested workflows, the engine is integrated as a child process of another engine. In workflow conversion, the engine is integrated through workflow language conversion. We describe and evaluate these architectures with metrics for assessment of integration complexity, robustness, extensibility, scalability and functionality. Tight integration and task encapsulation are the easiest to integrate and the most robust. Extensibility is equivalent in most architectures. The pool model is the most scalable one and meta-workflows are only available in nested workflows and workflow conversion. These results provide insights for science gateway architects and developers.     

有导向变异算子的无线Mesh网负载均衡算法研究*

为了提高无线Mesh网络(WMN)的传输性能,提出基于有导向变异算子的进化算法GM-EA(guidedmutation EA)来优化WMN网关负载均衡问题。在已有的WMN负载均衡算法基础上,GM-EA算法通过结合粒子群优化的方法,更好地利用种群中的全局信息,在较少迭代次数下可以达到网关数量和负载均衡两方面的优化。仿真实验表明,GM-EA算法以增加执行时间为代价下得到的网关数量与比其他算法得到的结果更优;在网关负载均衡方面,该算法也取得较好的结果。     

An architecture for residential Internet telephony service

Network gateways are used to set up calls between the public switched telephone network (PSTN) and the Internet, but existing gateways support a relatively small number of lines. To meet the scalability and availability requirements of mass-market deployment of carrier-grade telephony services, the authors propose an architecture based on the decomposition of Internet gateway functionality. The media transformation function of today's H.323 gateways is separated from the gateway control function, and intelligence is centralized in a call agent. The Media Gateway Control Protocol is introduced; MGCP is an Internet draft currently under discussion by the IETF for standardizing the interface between a call agent and the media transformation gateway     

基于PSO的无线Mesh网关优化部署算法

无线Mesh网关的优化部署目标是对一给定的无线Mesh网络,合理地确定网关部署的方案,在满足用户通信时延、通信带宽以及网关相关属性约束(如网关的度,簇度数)的前提下,使得网关数量最少、网关间负载均衡以及总体通信代价最小。利用粒子群算法在多目标寻优方面的优势,提出了基于粒子群的无线Mesh网关优化部署算法。对粒子的速度、速度的相关运算规则和粒子的运动方程进行了重新定义与设计,然后提出了基于网关启发式初步部署与优化的二阶段粒子群优化算法。理论分析与仿真实验表明,基于PSO的优化算法得到的网关数量不劣于其它算法得到的结果,而且在其它性能指标方面:通信代价、网关节点数量、负载均衡方面优势明显,与Recursive_DS算法的相比分别提高了38.15%,7.85%和7.3%。