End User Architecting

End User Architecting

Vishal DwivediInstitute for Software ResearchCarnegie Mellon University

[email protected]

Advanced User Interface Software

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Carnegie Mellon University, School of Computer Science

If you build it, they will come…

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“Hundreds of end user programming tools have been created in this hope. Not every tool succeeds. Many of them are built at a high cost, and are impoverished…”

Life may have been much better if everyone did not start from scratch…


Agenda Motivation/Definitions End User Architecting Examples

Abstractions for dataflow, pub-sub, … Style and the user interface elements Analyses

Composition of user interfaces (and why it is a hard problem)

A framework for End User Architecting

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Definitions “Software Architecture”

‘‘The software architecture of a computing system is the set of structures needed to reason about the system, which comprise software elements, relations among them and properties of both.’’ – Garlan and Shaw

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• High level of design abstractions and analysis

• Emergent properties• Reuse of design styles, patterns,

and frameworks


Definitions “Architecture Style”

A style defines the computation model, vocabulary consisting of elements such as components and connectors, their interfaces, and the constraints that they must obey.

Examples: dataflow, pub-sub, client-server, pipe and filter

5Gregory R. Abowd, Robert Allen, David Garlan, Using Style to Understand Descriptions of Software Architecture,” SIGSOFT ’94:


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“Architecture Style” Factors out common infrastructure. Allows configuration with additional details. Captures the domain elements and constraints on their usage. Are translated into required technology-specific vocabulary.

Definitions


Recalling Brad’s Lecture “Layers of UI software”

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ApplicationHigher Level Tools

ToolkitWindowing System

Operating System


Recalling Brad’s Lecture For example: SUIT’s architecture

8Pausch, R., Conway, M., & DeLine, R. (1992). Lesson Learned from SUIT, the Simple User Interface Toolkit. ACM Transactions on Information Systems, 10(4), 320-344.


Architectural Layer

Adding an additional architecture Layer

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Execution Platform

Architectural Layer

User interface Visual Language

Domain-specific architectural styles

Platforms like SOA, SCA etc

Guidance Translation

Monitoring Adaptation

Analysis

Code Generation


End User Architecting Similar to end-user programming, it recognizes up front that the

key issue for end user programming is bridging the gap between available computational resources and the skill set of the users who must harness them

[Nardi,93]

But unlike end-user programming, it seeks to find higher-level abstractions that leverage architectural techniques for defining the domain, supporting compositions, and aiding in tradeoffs and analyses.

Three key elements to the approach An architecture layer between the user interface and execution

environment supports explicit representation of end‐user compositions A reusable style that can be specialized for specific domains A graphical front end for composition and for analyzing and executing

compositions

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Architecture layer between user interface and execution environment Raises level of abstraction, making it easier for users

to understand the vocabulary Provides a basis for architectural analysis, guidance,

composition

Architectural styles help domain specialization Styles define the vocabulary for compositions in a

domain. Domain-specific specializations for each domain

further refine vocabulary, rules, and concerns

End User Architecture Approach

Carnegie Mellon University, School of Computer ScienceExamplePub-Sub Style (Ozone Widgets)

12https://www.owfgoss.org


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Ozone provides a framework for creation and integration of HTML widgets Widgets can publish and subscribe to channels to

communicate messages. End users can specify which pairs of widgets can

send/receive messages

Widget A Widget C

Widget BPublish

Subscribe

Subscribe


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Key features of End User Architecting: Architectural Style: Compositions are defined using a variant

of a publish-subscribe style that takes into account the idea of restrictions.

Architecture Representation: Ozone widget configurations are represented as explicit architectural models, that indicate which widgets are involved in a composition and the communication topology.

Analysis: such as which widgets are communicating, whether there are data mismatches over publish-subscribe channels, how to restrict communication to minimize event messaging…

Reuse: Component based reuse User interface: Additional widgets to inform the user about

restrictions, widget communications and other analyses.

Carnegie Mellon University, School of Computer ScienceExampleDataflow based compositions

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Root Style

Specialization for Neuroscience

Specialization for Intelligence Analysis

ExampleDataflow style vocabulary (created by refinement)

Vishal Dwivedi et al. An Architectural Approach to End User Orchestrations. ECSA 2011: 370-378

Carnegie Mellon University, School of Computer ScienceExampleDataflow UI elements

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Workflow EditorYUI Layout

Perspective (Compose, Execute, Analyze)

YUI Layout

Palette

Module

Canvas

Service

(Container)

DataService

Multi Port Service

• YUI framework defines the GUI widgets, events and controls, utilities• A style maps these compositions to an architectural representation• This is analyzed for various quality attributes.

Carnegie Mellon University, School of Computer ScienceExampleDataflow analyses

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Architectural specification allows domain-specific analyses, such as:• Data mismatch• Security • Ordering• Domain-specific constraints (e.g. above diagram before a brain image is visualized it should be registered and converted in a specific format.)

Resolving Data Mismatches in End-User Compositions, ISEUD 2013

Carnegie Mellon University, School of Computer ScienceExampleDataflow Style (Widgets)

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Key features of End User Architecting: Architectural Style: Compositions are defined using a variant

of a dataflow style that is specialized for a domain Architecture Representation: Workflows are instances of the

style. Analysis: custom analyses for data-mismatch,

security/privacy violations, ordering analyses, etc. Reuse: Reuse of component vocabularies, compositions, etc. User interface: A dataflow based interface having element

vocabulary defined in a domain-specific style.


The Bigger Problem

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Creating compositions today is difficult for end users due to:

Complexity due to low-level details For example, parameters, file systems, paths, operating systems, etc

Lack of support for error resolution For example, Analyses for quality attributes such as security and

privacy and other syntactic and semantic problems.

Conceptual mismatch For example, “Remove Image Noise” as opposed to calling the

specific program(s) to perform this function.

Composing UI components is even harder!


Composing User interfaces with Interviews

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The premise: Object oriented User interface code Separate interactors Iconic interfaces Tradeoff at the level of GUI consistency.

Mark A. Linton, John M. Vlissides, Paul R. Calder: Composing User Interfaces with InterViews. IEEE Computer 22(2): 8-22 (1989)

But what if GUI objects have semantic meanings?


Building blocks for reusability

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Anders I. Mørch: Application Units: Basic Building Blocks of Tailorable Applications. EWHCI 1995: 45-62

Tailoring by:• Extension and refinement• Specialization of components and virtual binding

But who does that?


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But certain communities have handled this wellE-sciences (e.g. LONI pipeline, Taverna)

Things they did well:• Componentization of functionalities as services• Pluggable visual components, with search and discovery• And most importantly, creating an ecosystem with different developer roles.

Loni Pipeline demo

http://pipeline.loni.ucla.edu/products-services/pws


HALO: a framework for End User Architecting

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Current work HALO SDK (and plugins) for:

Architectural representation, Packaging and reuse Data reference Multiple analyses Component registry Execution-support

Hypotheses: Associating architectural specifications with user interfaces will allow a

greater level of analysis and reuse. Many tool capabilities will be provided by the framework. So this will lower

cost of tool development and improve quality.

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Questions?

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References Anders I. Mørch: Application Units: Basic Building Blocks of Tailorable Applications. EWHCI 1995:

45-62 David Garlan,Vishal Dwivedi,Ivan Ruchkin and Bradley Schmerl. Foundations and Tools for End-

User Architecting. In Proc. 17th Monterey Workshop, Oxford, 2012, UK David Garlan, Bradley Schmerl, Vishal Dwivedi, Aparup Banerjee, Laura Glendenning, Mai

Nakayama, and Nina Patel. Swift: A tool for constructing workflows for dynamic network analysis. http://acme.able.cs.cmu.edu/pubs/show.php?id=333, 2011.

Gregory R. Abowd, Robert Allen, David Garlan, Using Style to Understand Descriptions of Software Architecture,” SIGSOFT ’94:

Mark A. Linton, John M. Vlissides, Paul R. Calder: Composing User Interfaces with InterViews. IEEE Computer 22(2): 8-22 (1989)

Ozone Widget Framework https://www.owfgoss.org Pausch, R., Conway, M., & DeLine, R. (1992). Lesson Learned from SUIT, the Simple User

Interface Toolkit. ACM Transactions on Information Systems, 10(4), 320-344. Perla Velasco-Elizondo, Vishal Dwivedi, David Garlan, Bradley Schmerl and Jose Maria

Fernandes. Resolving Data Mismatches in End-User Compositions, In Fourth International Symposium on End-User Development (ISEUD), 2013, Denmark.

Vishal Dwivedi et al. An Architectural Approach to End User Orchestrations. ECSA 2011: 370-378

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End User Architecting

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