Access and Interfaces

Figure 23 shows the access and interfaces patterns.

IT Model

Simple Scripts & Control Functionality

Figure 23.:This is an overview of the e-Science access and interfaces patterns.

Name Single Sign-On

Classification IT Experiment Model

Intent Speeds up the research process and increases the acceptance of the eExperi-ment solution.

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Problem Users need to key in a username and a password for every IT system, which they use for the eExperiment. This takes too much time [94].

Context A user wants to access different IT systems within an eExperiment.

Solution Implement a mechanism, where the user has to sign on once. After that, this mechanism handles the sign-on to the different IT systems.

Example Riedel et al. describe a single sign-on solution, that is based on X.509 certifi-cates of scientists for authorization [94].

Relationships

-Name Role Based Access

Classification IT Experiment Model

Intent Ease of user access management.

Problem Scientists and stakeholders need to have access to IT Systems. Different people need to have similar access rights within the IT systems. It requires much effort to grant each user every single right.

Context Users, who require different access rights for an IT system. There exist several users, which require the same rights.

Solution Implement role based access. Rights are granted to roles first. Then a specific user gets the role and therefore the rights, that are granted to the role.

Example An example for role based access can be found in [109].

Relationships

-Name Graphical User Interface Classification IT Experiment Model

Intent Helps the scientist to interact with the eExperiment solution.

Problem How to interact with the eExperiment solution?

Context Scientists that want to perform an eExperiment and are used to GUIs.

Solution Provide the scientist with a GUI for conducting the eExperiment..

Example Biologists prefer Web-based portals [94].

Relationships

-Name Command Line Tools

Classification IT Experiment Model

Intent Helps the scientist to interact with the eExperiment solution.

Problem How to interact with the eExperiment solution?

Context Scientists that want to perform an eExperiment and are used to command line tools.

Solution Provide the scientists with command line tools for conducting the eExperi-ment.

Example Physicists like command-line interfaces in general and try to avoid GUIs [94].

Relationships

-4.4. IT Experiment Model

4.4.7. Miscellaneous

In Figure 24 an overview of the miscellaneous patterns on the level IT experiment model is given.

Simple Scripts & Control Functionality

Figure 24.:This is an overview of the miscellaneous patterns on the level IT experiment model.

Name Tight Coupling

Classification IT Experiment Model

Intent Helps to optimize the performance of applications, that are not frequently changed.

Problem How to optimize applications?

Context Scientists, that want to optimize the performance of the applications.

Solution Use tight coupling of components. This means the components make many assumptions about each other.

Example An example for a framework, that was build for tightly coupled, high perfor-mance simulations is the Cactus framework [43].

Relationships <Conflicts> Loose Coupling

Name Loose Coupling

Classification IT Experiment Model

Intent Helps to create a flexible and robust distributed application.

Problem How to reduce dependencies between distributed applications and their distinctive components [32]?.

Context Components in a distributed environment make assumptions about each other. These assumptions should be limited for flexibility and robustness reasons [32].

Solution Use an intermediary that handles format transformation, routing and ad-dressing [32].

Example The SimTech WfMS uses a service bus for simulation workflows. This service bus handles data transformation, message routing and service discovery and selection [51].

Relationships <Conflicts> Tight Coupling

Name Model Update Strategies Classification IT Experiment Model

Intent Helps to update the models within an eExperiment.

Problem The data flow within an eExperiment is continuous. The model of the IT system needs to be changed. In a standard procedure the analysis is stopped.

Then the model is updated. After this the analysis is started again. During the update, portions of the data flow cannot be analysed and get lost.

Context There is continuous data flow in an eExperiment. The model of the eExperi-ment needs to be updated.

Solution Implement a mechanism to reduce the downtime of the system during the update.

Example In [127], Wickramaarachchi et al. formalize different update models. In addition, they provide metrics for evaluating update strategies.

Relationships

-Name Communication Platform Classification IT Experiment Model

Intent Helps to improve the collaboration between the scientists.

Problem Scientists want to make comments and exchange thoughts about an eExperi-ment.

Context Scientists that conduct an eExperiment in a collaborative manner.

Solution Build a mechanism, that enables communication around an eExperiment.

Example Group-to-group communication is supported by the AccessGrid via high-speed networking and state of the art camera and display technology [49].

Relationships

-4.5. Infrastructure

This chapter comprises the patterns on the level infrastructure. Figure 25 shows the grouping of the patterns into concrete infrastructures and WfMS.

Infrastructure

Workflow Management

Systems Concrete Infrastructures

Used for Structuring Only Pattern

Figure 25.:This is an overview of the e-Science patterns on the level infrastructure.