A Generalized Architecture for A Generalized Architecture for Bookmark and Replay Bookmark and Replay TechniquesTechniques

Thesis ProposalBy

Napassaporn Likhitsajjakul

Outline

• Background• Problem statements• Objective• Methodology• Plan

BACKGROUND

Today’s Information system

• Information system is used to capture key information.

- Analysis component is the most important part since it will be used for decision making process or illustration

• Merit of information system is that, given some amount of data, it should yield meaningful analysis results.

Today’s Information system

• Information analysis is “iterative” in nature• But conventional systems mostly focus on the

final artifacts of analysis (e.g. report)- Static, lack of exploratory characteristics - Relevant information during the analysis process is lost

while it is useful

Why relevant information during analysis process is important?

• Exploratory Data Analysis (Tukey, 1977)

- Not only focus on dataset, but also the exploration process used to produce the results

• Analysis process is iterative (Goldstein et al, 1994)

- Analysts usually navigate back and forth to a point in time

- But mostly today’s interfaces does not support that since it just focuses on one state at a time

Bookmark and Replay State

• Analysis activities can be done in effective and efficient ways by keeping the history of exploration and analysis process along with reporting artifacts

- Freely navigate to an interested point in time- No need to start over from the beginning- Reusability of analysis context

• State must be saved in some way that can be reconstruct later

Bookmark and Replay State

• Bookmark and replay concept can be very easy in some static applications

- e.g. Website bookmarking in a web browser

• Can be very difficult in dynamic application- e.g. Simulation (results at every second, have to run the

whole simulation again)

• But it is possible in User Interface and Analysis- e.g. Statistical analysis, GIS application

Bookmark and Replay State

• There are 2 main approaches currently used in applications:

Bookmark Replay

Copying State • Save the snapshot of whole state

• Restore the milestone snapshot of state

Command pattern

• Ensure actions have corresponding “compensation action” that nullify effects

• Record sequence of command to reach the desired state

• Issue the compensation actions of recorded command to the current state

• Issue recorded command to the initial state

PROBLEM STATEMENTS

Problem #1

• Data exploration process is left behind after provided output artifacts.

- Analysts cannot backtrack /navigate to the interested point that has previously explored

- Exploration process cannot be reused- Limits the efficiency and effectiveness of analysis

Problem #2

• The currently used method for bookmark and replay introduced a lot of overhead in execution time and memory usage.

- Copying State: Overhead in saving and restoring state

- Command sequence: Overhead in restoring state Not possible for every commands Difficult to design and implement

OBJECTIVES

Objective

• To develop an architecture to support navigation to a point in the history of analysis in dynamic application

- Design and implement two alternative

• To analyze and evaluate resource required for typical interaction pattern in real case study for the alternatives

- Effectiveness, limitation- Optimization, improvement

Objective (cont.)

• To generalize the architecture for applying to other dynamic applications

- Develop a set of architectural patterns for different application domains

Scope and Limitation

• Focus on 2 alternatives for history navigation: state copying and command patterns

• Focus on GIS application (SavGIS) as an example of dynamic application

• Extend to support navigation to the history of analysis

RELATED WORKS

Time Travel Interface

• Extension of Visage software• Backtracking and investigating alternative scenarios

- Record history of events and modeled them as a tree- Decouple actions from states of application

(Derthick & Roth, 2001)

Drag the slider to go back to the history

Temporal model for undo/redo

• Record command history during a session • Command history is modeled as a directed graph in temporal order

• Undo/redo by invoke/reverse operations• Difficult to apply command object pattern (Flatland application)

- Effects of operation must be known in advance to enable undo- Difficulty in design and implementation

Linear timeline

(Edward et al., 2000)

METHODOLOGY

Overview

Methodology

• Step 1 Select alternative to be analyzed- Start with “Command pattern”- Followed by “State copying” after finished Step 3

• Step 2 Modify application to support alternative- Implement an extension to coordinate states, history

of commands, and images snapshot of state

• Linkage between screenshots and history of commands• Navigability between states in history

Command pattern• Navigability between states in history

State copying

Methodology (cont.)

• Step 3 Analyze alternative with a case study- Resource requirement- Interaction pattern- Limitation- Potential for improvement (optimization)

Methodology (cont.)

• Step 4 Generalize the architecture- Classify application domains- Develop a set of architectural pattern for different

application domains

PLAN

August Semester

Tasks Aug Sep Oct NovSelect alternative: Command pattern

• Study alternatives

Modify application to support “command pattern”

• Study SavGIS software

• Implement extensions

Analyze “command pattern” with case study

• Collect case study

• Analyze system

January Semester

Tasks Jan Feb Mar AprSelect alternative: State copying

• Study alternatives

Modify application to support “state copying”

• Study SavGIS software

• Implement extensions

Analyze “state copying” with case study

• Analyze system

Generalize architecture

References

• Edwards, W. K., T. Igarashi, et al. (2000). A temporal model for multi-level undo and redo. Proceedings of the 13th annual ACM symposium on User interface software and technology. San Diego, California, United States, ACM.

• Derthick, M. and S. F. Roth (2001). "Enhancing data exploration with a branching history of user operations." Knowledge-Based Systems 14(1-2): 65-74.

• Souris, M. (29 June 2010). "SavGIS - Geographical Information System". Retrieved 28 September, 2010, from http://www.savgis.org/.

• Unger, B. W., J. G. Cleary, et al. (1993). An external state management system for optimistic parallel simulation. Proceedings of the 25th conference on Winter simulation. Los Angeles, California, United States, ACM.

Q & A

Comments

• Change “dynamic apps” to “EDA apps”• Iteration = 1 month (implement, analyze)• Analyze 2 method [copy state + macro]at the same time

- Look for more alternative (combination of state copy + command)

• This semester 2 iterative with about 3 case study• Focus more on analysis not implementation

- How state is bookmark? Database?

• Make it like Visage• State in SavGIS = content of map not interface