The work flow assistant (WFA) is an advanced technology project under the shuttle processing data management system (SPDMS) at Kennedy Space Center (KSC). It will be utilized for short range scheduling, controlling work flow on the floor, and providing near real-time status for all major space transportation systems (STS) work centers at KSC. It will increase personnel and STS safety and improve productivity through deeper active scheduling that includes tracking and correlation of STS and ground support equipment (GSE) configuration and work. It will also provide greater accessibility to this data. WFA defines a standards concept for scheduling data which permits both commercial off-the-shelf (COTS) scheduling tools and WFA developed applications to be reused. WFA will utilize industry standard languages and workstations to achieve a scalable, adaptable, and portable architecture which may be used at other sites

Johnson, Earl

Wilkinson, John

English

NASA Technical Reports Server

N91-20680
KSC'S WORK FLOW ASSISTANT
ABSTRACT
The Work Flow Assistant (WFA) is an advanced
technology project under the Shuttle Processing
Data Management System (SPDMS) at Kennedy
Space Center (KSC). It will be utilized for short
range scheduling, controlling work flow on the
floor, and providing near real-time status for all
major Space Transportation Systems (STS) work
centers at KSC. It will increase personnel and
STS safety and improve productivity through
deeper active scheduling that includes tracking
and correlation of STS and Ground Support
Equipment (GSE) configuration and work. It will
also provide greater accessibility to this data.
WFA defines a standards concept for scheduling
data which permit both commercial off-the-
shelf (COTS) scheduling tools and WFA developed
applications to be reused. WFA will utilize
industry standard languages and workstations to
achieve a scalable, adaptable, and portable
architecture which may be used at other sites.
John Wilkinson and Earl Johnson
Kennedy Space Center
Lockheed Space Operations Company
M.S. LSO-002
TitusvUle, Florida 32780
inspections, e.g. correcting tile damage incurred
during the previous mission. The limitation is
that re-scheduling is done as a one day delayed
reaction reconciling differences between
planned and actual schedules.
In response to this need, the Work Flow
Assistant (WFA) project of Kennedy Space
Center's Shuttle Processing Data Management
System (SPDMS) was initiated. This system is
envisioned as a knowledge-based scheduling
assistant acting primarily at the work center
level. WFA will include the capability to: track
schedule progress, the STS and ground support
equipment (GSE) configuration and critical path
on a near-real-time basis; and screen all work
for compatibility to configuration. It will also
provide the active scheduling and resource
balancing of open standard work and for
integration of non-recurring work into the
schedule.
STRUCTURE AND FUNCTION
1. INTRODUCTION
The task of preparing the Space Shuttle for
flight is complex and involves systematically
moving the shuttle through a series of work
centers. The preparation activities at each work
center involves coordination of a sizeable team
of personnel and materials as well as the
cumulative execution of some 25,000 operations
per shuttle flow. While this coordination effort
is scheduled daily in advance based on planned
work and durations, the actual work required
may vary by as much as 40% due to non-
recurring activities revealed by scheduled
Functional aspects of the WFA will include:
* Information collection, assimilation, and
dissemination.
• Multi-perspective user interface.
• Electronic signature capability.
• Tracking task events (e.g. enable, cancel,
start, stop, hold, and resume).
• Dynamic critical path projection.
317
https://ntrs.nasa.gov/search.jsp?R=19910011367 2020-03-19T19:06:06+00:00Z
• Interactive queries
Status (e.g. configuration, activities in
progress, etc.).
- What-if schedule assessments.
- Meta task event inquires (e.g. area close-
out}.
• Incorporation of non-recurring or non-
standard work into scheduled activities.
• Proposed scheduling data exchange format
Figure 1 presents the top level logical
organization of the WFA. Planning and
scheduling, ranging from multi-mission 5 year
planning to work center work package release for
the next 11 days, will be accomplished through
an integrated set of SPDMS host based
applications . WFA will then construct and
maintain a more in depth schedule taking
individual resources and work center GSE
configuration into consideration. WFA will receive
transactions to start, stop, hold, resume, cancel
and complete work. WFA uses this data to verify
that prerequisite tasks are complete and that the
current configuration is compatible before
allowing work to begin. WFA also tracks schedule
progress and configuration as the tasks are
received; and maintains schedule data, critical
paths and configuration in near real-time. WFA
assists floor supervisors in the work centers to
balance work and resources and to gain
increased visibility into work center status. It
assists flow managers and controllers of multi-
work-center resources , e.g. quality or safety
personnel, on a flow or multl-flow level to track
and manage tasks in their purview. Near real-
time status is also made available throughout KSC
to keep the NASA and contractor work force
informed on the progress of STS testing and the
effect on their respective organizations.
3. CENTRAL CONCEPTS
The following presents the hinge-pins upon
which WFA is founded. The approach to
standards and modularity takes on unusual
importance in that it determines whether WFA
will be a single-use application or a reusable tool.
Also information distribution and user
customization concepts will heavily affect how
well the many and varied user groups are served.
3. I Standards
Like all major government installations, KSC has
workstations, computer equipment and software
from many vendors. Data paths required by the
WFA span multiple vendor platforms and software
packages. Standards utilization will lessen the
implementation cost and have a positive effect on
the extent of reusability. Using standards as the
platform, rather than a single vendor model or
line, permits maximum use of existing equipment
and allows new acquisitions to be based on
benchmark and cost considerations uniquely for
each requirement.
Where no formal standard exists, ad hoc
standards supported by multiple vendors are
preferred.
Candidate multl-vendor standards or emerging
standards are available which cover most areas of
concern. One notable exception, for WFA's
purpose, is the absence of standards governing
the exchange of scheduling data between COTS
scheduling applications. The existence of such a
"standard", albeit ad hoc and limited in agency
scope, will reduce the need for further custom
developed software tools for WFA, and permit
WFA technology to be more easily reused.
Analogous to the definition of an Application
Portability Profile for Posix by the NIST, WFA
development will include a set of APP tests and
benchmarks to validate vendor independence
and vendor supportability of a WFA release.
3.1.1 Industry and Adhoc Standards
When the multi-vendor support requirement is
added to standards selection, the standards
picture changes significantly. But without multi-
vendor support, there is in effect no standard.
While project approval of selected standards has
not yet been secured, adequate candidate
"standards" appear available for the following
project roles: platform equivalent configurations,
operating system, network connectivity, database,
languages and graphical user interface.
3.1.2 Schedule Information Interchange Format
A unifying concept of the WFA is our proposed
Scheduling Information Interchange Format
(SIIF), which provides a logical common
communications medium for transmitting and
receiving scheduling information (Figure 1). The
318
_licatiOns
i
Short Range
Scheduling
(now-1 ldays)
Work
Status
Entry
Long Range, _ Intermediate
Planning Planning Range WFA/
(3mos-5yrs) (.5-3mos) Scheduling Floor
(.5-1mos) Supervisor
WFA/
Floor
Manager
SIIF: Scheduling Information Interchange Format
WFA/
Shared
Resource
Manager
WFA/
Scheduling WFA/ SI1F/ WFA/
Engines Planners Query Query WFA/Status
Transactions
Transactions
Status
(Advisory
Systems)
Figure 1: Work Flow Assistant Logical Organization
SIIF defines a standard method for storing
scheduling information in an SQL database form,
as well as interface protocols for requesting
services for each class of scheduling tool. Custom
applications requiring SIIF scheduling services
follow the SIIF protocol for requesting services
from any SIIF scheduling tool.
The primary benefit is to make scheduling data
readily accessible and scheduling tools
interchangeable. Standardization of data is the
next logical step for standards. After all, it is the
data itself upon which decisions are made.
In order to make the SIIF practical, all
participating data must be stored in SIIF rather
than in the internal format of a particular tool.
Also, each participating tool must be interfaced to
the SIIF and participating applications must
utilize the SIIF protocol. Naturally, this is not an
all or nothing affair. Benefits will accrue
proportional to usage. SIIF definition and
compliance represents a significant decision, not
yet made, that will require careful deliberation
and active commitment.
3.2 Mix N'Match Components
The SIIF will be used analogously to a computer
backplane for disseminating scheduling
information into which scheduling tools and
scheduling application can be installed (Figure 1).
Each tool or application is installed via an
interface program that maps the protocol and
format of that product to the protocol and format
of the SIIF. Tools are envisioned to be installed
by functional category and to appear to the SIIF
as having the same functional interface, as other
tools in the same category. New COTS scheduling
tools can then be installed by developing or
modifying an existing interface program.
Scheduling applications can use the installed
tools as building blocks. Users can utilize any tool
of a tool category to access any of the data
maintained in SIIF format.
WFA scheduling engines are tools of special
importance. They have a high level of
functionality permitting them to be used by most
scheduling applications and are scalable
permitting hardware platform performance to be
selected based on performance requirements.
319
3.3 Active Versus Reactive Scheduling
The traditional scheduling approach is reactive;
that is schedule, do the work, periodically review
progress versus the schedule, and then
reschedule to resolve discrepancies In
contrast, WFA will receive task progress
transactions (start, hold, complete, resource
assignment, etc.) electronically and immediately
update schedules and configuration status for
each work center. Critical paths and individual
resource utilization will also be tracked in near
real-tlme. WFA will also assist floor supervisors,
responsible for controlling work flow through a
work center, remain abreast of work status, and
in balancing resources and ordering tasks to
improve productivity and minimize schedule
impacts.
3.4 Configuration Based Scheduling and Safety
Assistants and direct support serve the personnel
actively working in and around a work center to
accomplish work. Assistants are planned to act as
intelligent aids to flow-strategic personnel
including floor supervisors, planners and flow
managers.
Interactive query and reports are provided to
meet special user group needs for access to
schedule and status information.
Advisory systems provide work and configuration
data in a broadcast mode to user workstations
that are primarily IBM PC compatible and utilize a
set of KSC developed tools supporting user
tailored display of that information. This
distribution service makes flow and configuration
information available efficiently throughout KSC in
a low overhead computational manner and can be
disseminated to other centers as well. A number
of other advisory systems are being constructed at
KSC that work in a similar manner using the same
resources and technology.
Scheduling and tracking at the work center level
will uUlize knowledge of the physical aspects and
current configuration of the work center and the
STS elements being processed as related to the
tasks being performed. Configuration data
includes considerations such as Orbiter power
status, position of test stands and STS flight
moveable surfaces, payload bay door configuration,
etc. With each task, any configuration
requirements or prerequisites must also be
identified by appropriate organizations. Using
this information, WFA schedules the work by
taking configuration into consideration. Current
configuration state will be gathered through
manual entry, completion of a scheduling task for
which a configuration effect is identified, or by
processing STS and GSE real-time measurement
data received from the firing rooms at KSC. WFA
also tracks the current configuration and verifies
that configuration requirements match
configuration computed state and that all
predecessor tasks are completed before
permitting work to commence. While this
method is not fool proof, it should significantly
improve safety to the work crew and the STS.
3.5 Information Distribution
Three levels of information distribution service
are provided by WFA. These services disseminate
near real-time status from work centers
supported by WFA. The three distribution levels
are: assistants and direct support; interactive
query and reports; and advisory systems.
3.6 Multi-perspective Malleable User Interface
Each work center and user group have different
needs for data content and form for the user
interface as well as queries and reports. "One
size fits all" is not appropriate in this context.
The WFA strategy is two fold. First, provide a
core capability that is independent of specific
work center or user group needs and provide
technology for user customization. Secondly, turn
over the customization responsibility and task to
user groups.
Since the SIIF is an SQL database, interactive
query and reports are readily generated via the
provided vendor SQL COTS tools. WFA does not
provide these reports and queries but rather,
ensures that all scheduling and status information
is accessible through them.
The user interface for the assistants alternately
presents information to the users as lists,
drawings and various scheduling charts, all user
selectable. The user can define as many drawings
as needed to tailor the interface to the work area
itself. Work center status can then be directly
depicted on these drawings. This capability is
presently being demonstrated to users and has
been well received. Figure 2 illustrates various
forms of the user interface for the assistants.
Advisory system displays are also fully defined by
the users.
320
Figure 2: Flexible User Interface
321 ORIGINAL PAGE IS
OF POOR QUALITY
4. PROJECT BENEFITS
Program benefits range from aspects as diverse as
technology insertion, and comparative
validation/assessment of new products, to system
maintenance. And as new products are
introduced, they may be evaluated in situ rather
than in a standalone mode.
The WFA will make information readily available
to a large segment of the KSC user community,
that has previously been assessable only via
personal contact with numerous individuals with
area specific knowledge.
Data sharing across tools, systems and
organizational groups is a natural outgrowth.
Consumers of scheduling information and
application developers as well should receive
something new in tool selection...a choice.
Near real-time interactive decision making aids
should improve productivity and permit more
timely informed decisions
Once the proposed SIIF standard is in place, a
synergistic effect may occur, and unforeseen
latent benefits may accrue.
If successful, SIIF may encourage others within
NASA or contractor organizations to undertake
data format standardization efforts in other areas.
and Planner; and,Bob Gargen, et al of the
Lockheed Artificial Intelligence Center, for their
addition of Configuration Based Scheduling to the
Ames project.
REFERENCES
Jamieson, J.R., Scarl, E.A., & Delaune, C.I., "A
Knowledge Based Expert System for Propellant
System Monitoring at the Kennedy Space Center",
Proc. 22nd Space Congress, Cocoa Beach, FL, pp.
1-9.
Wilkinson, J., Tulley, J., "Automated Analysis of
Shuttle Wiring Using SCAN", Proc. 25th Space
Congress, Cocoa Beach, FL
Zweben, M., Deale, M., Eskey, M., "Anytime
Rescheduling', Submitted to AAAI-90.
5. CONCLUSION
As reflected from user feedback of
demonstrations of the first phase prototype, WFA
is envisioned by users as a ground breaking
project with much promise. However the
challenge is also real'. WFA is being therefore
deployed in separate phases to mitigate that risk.
Each major phase also contains a prototyping step
to gain early user critique and permit project
mid-course corrections. The success of this
system and its extent are dependent upon factors
which to a large measure require the persistent
commitment and willingness of contractors,
vendors and NASA to make WFA an actuality
ACKNOWLEDGEMENTS
The authors wish to thank Monte Zweben,et al of
the NASA Ames Research Center for their
contributing work involving the Ames Scheduler
322


KSC's work flow assistant

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server